aboutsummaryrefslogblamecommitdiffstats
path: root/lib/asn1/src/asn1ct_check.erl
blob: 321f4147f566d7d76f4eb27872a5204cc15493ba (plain) (tree)
1
2
3
4
5
6
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
                              

                   
  
                                                        
  










                                                                           
  







                                               
                                              

































                                              
                                                                   
                             
                                                                    

                                                                                                                         

















                                                                        
                                                                                           

                                                                   

                                            

 
                              






                                                              
                                                                                      







                                                               
                                   



























                                                                  
                                                             
                                                          

                                                                     





                                                                        
                                               




                                                  



                                                                 











                                                                          
            
                             






































































                                                                
                          
                         




                                                         

                           


                                                                         

        



                                                       
        
                                                                                         
                                    









                                                                             
 










                                                               
                               













                                                                     
                   





                                 


















                                                          







                                                                         
                                



                                                             
                                                             


                                  
                                                  


                         
                   



                                 
                          





                                                                         
                                                       

                            
 


                                          
 
                                                          
                             






                                                            
                   




                                 
 



                                          
                            







                                                         

        
                                          


                                                           
                                                             









                                                                         







                                                      
    


                                               





                                                     



                                                                    
                                                                 
                               













                                                          
                               




                                                            
                               



                                               

















                                                                        
                                                         
                                                                 
                                      


                                                            
                                                      

                                                       

                                   











                                                                
                                                                     












                                                                                   









                                                                         


                                                                     
                                                          













                                                                  





                                                                 






                                                                                 
                                                                          
                                                                      





















                                                                                                                             



                                                                     
                                                                   


                                                           












































































                                                                                         






                                                                        



                                                                        




                                                                  
                                                                    






                                                                             


                         
                               












                                                                                
                                                                    
                  


                                                                    


                                              
            

                                                             
                                                   


                                                                     


                                                                 

                                             
























                                                                      











                                                            

















                                                                            




































                                                                            

                                             










                                                                        



                                          












































                                                                               



                                                           
                                                       
                                                




                                         
                                                            


                                                  
                                                     





                                                           
                                                 







































































                                                                   
 
                                                
           
                                                            
                                                                    






                                                    
 














                                                                                          
                                                 
                                               







                                                         

        












                                                                            

                           
            
                                        






















                                                                              




                                                                   
                                                         





                                                
        


                                     























                                                               







                                                 
 
                                                           





                                      
                                                 


                            
                                




                                                                         
                                                
        
                                                 
                         




                                                   
    







                                                                                                            
                                           








                                                                                

                                             


                                                                      

                                                         
                                           
































                                                                                  
                                                                         















                                                         
                                                     














                                                                           

                                             
                  
                 















                                                                          
                                                 






                                         






                                                               

                                        
                                                        
                                        










                                                         

        





                                                            










                                                       
                





























                                                                          

                                      





                                                                             
                
                                                        















                                                            

































                                                                   
                   




































                                                                                  
                                                  























































                                                                                        
                                                                    

















                                                                           
                                                        











                                                                

                                                           







                                                             


















                                                                              




                                                                             
                                                                               


                                                          



                                                            
                                           

                                  
 
                                              
                               
                                   
                                         
































                                                                          




                                                                 
                          



                                          
                                                       




                                                              
                                                                 
        
 
                                                   
                                              

                                                                    

                                                              
 

















                                                                        
 













                                                                     

                                                            

                                                                             



                                                                              
                

                                                                        
        






















                                                                   
                                                                






                                                                                     
                                              
                                                                            



                                                                            








                                                                         



                                      
              




                                                       
                                                                     
                                  
                                                                       
                         
                             






                                                                     
                                                       
                                                                  















                                                                              
                           






                                                                   
                                                                      
                                       
                                                                      
                        
                                                               
                                                                            

                                                                          










                                                          


                                                      
 








                                                                                 
            
                                                
        






















                                                                          
                    
                                                            

                
























                                                                        

                                                                             
                                                                
                        
                                                        

               















                                                          





































                                                      










                                                      













                                                          
 
                                    



                                                         

                                                      






                              










                                                                                       
                                          
 



                                                                             
                                  
                           
                                          








                                                         
                                                        



                                                   
                                               

                                               
                               
                                            











                                                
                                                














                                                              
                                                                                          
                                                                               




                                                     





                                                                  

                                              
 
                                                     
        






                                                                       
                        
                    
                                                        

                          
                                                        
               
        
                                                                       



                                                    
                                                
        

                                         
 



                                                                     

                                                
                                         
                                                

                                         






                                                      
                                                                
                

                                                                  

                                   

               
                                                        

        


                                                                    
                                                             



                                                   
                                                 
 











                                        




                                          
 

                                                     






                                                                              
                                  

                           
                                      
                           
                                      













                                                             
            
                                                     

        
                                       
                                              
 

                                                 






                                    




                                            
                             






                                                                 
                
                                         

        





                                                                       
                                         
        
                                                       
                       
                                                     
                                            
                                                

























                                                                             













                                                                  











                                                                           
                
                                         
                                                                                   






                                                            
        
 






                                                                        
                                                                                

                                                                       


                                








                                                               

                                                 
                                                                   
                                      
                 






                                                           

                                                           
                                                            

                                          
                                                                       






                                                                   


                                                   
                                 


                                                                





















                                                                        
















                                                               

























                                                                 

                                                                           


























                                                                                         
                                                              



















                                                                              
                                                                        




                                                                

                                                                       


















                                                   

                                   



















                                                                
                                                   
























                                                                            







                                                        

                                                                   

                                                       
                              







                                                                                  
                                               










                                                                           
                                                                      

                                                                      
                                                                   
                            
                                                                      
                                       
                                                                      
                                       
                                                                      







                                                              
                                                       




                                                             


                                                                 














                                                                                  


















                                                                                        
                                                                  
                                                                             
                                                                       





                                                                                   

                                                                              









                                                                                                 
                                                                

                    
                                                                   

                                                              
                                                                   

                                                              



                                                                            
                                                                                  



                                                                            
 

                                                                             
                                                           






























                                                                                      
                                                                       





































































































                                                                                              
                                                                





















                                                                                        






                                                                         
                                                            





                                                                      
                                                              

                                                                      

                                                                     








                                                                                         
                                                                                


                                     


                                                              




                                                                    


                                                               





                                                                      



                                                                      
                               
                          
            


                                                                               
                                                                        


                                                                  
                                         
 













                                                                       
                                                               
                 


                                                                          



             



























                                                                      

                                                                                  
                                                     

                                                    
                                                     

                                    
       

                       
    
                                           

                                     
                                                      

























                                                                                      




                                                                          
                          


                                                        



                                                             

                                                               
                                                                         
                                                   
                                










                                                                       






                                                                           




































                                                               


                                                     




                                                                 
                                                                   

                                                                   

                                 


































































                                                                            

                                                   




                                                                           




                                                                        
                                                  
                                                    
                                                 
                                                       
        









                                                                          
         




                                                                           
                
        





                                                                     
                                                   
                        

                                                    
 
                                                

                                                               
                              










                                                                               
                          

                                                         
                  
          
 
                                        



                                                                     










                                                                  

                                                                        








                                                                              






















































































































































































































































































































































































































                                                                              
 























                                                  




                                                           
                                  
                                 
                                    
 

                                                                          

                               

                                                                      
        

                                          
                                   
                    
                 
                                                
        

                                          
                                   
                    
                 
                                                
        
                                                                              
                                                
                                                        
      

                                                                    
                                                
                                                 

                                               
                          
      
 
                                               
               
                                  
                                                     
                               
                                                     
            
                     
        
 
                                           
       
                                                        




                                                            
 


                               





















































































                                                                                                            







                                                                    
                            


                                     
                                        


                                                                         


                    
 

                                  













                                                           










                                                               















                                                                             
                                                                   





                                                     
                                                                      





















                                                               
                                                                    


                                                
                                                                    











                                                                                      

































































                                                                      

                                                                 

        


                                            
                                             












                                                                         



                                                                        
                      

                                                                 
                                      

                                                                                       


























                                                                                    

                                                
 

                                                 
 

                                

                                                                   

                                                                      
            

                                                                          
            

                                                                        
            

                                                                            
            

                                                                            
         


                                                                              
            


                                                                              
                     

                                                                              


                                                           
                                                                



                                                                  
















                                                                                                                 
                                                    
        
 
                                                     




                                                                     















                                                                                        
 

                                                              
       




                                                      







                                                                                     
                                                     

                
                                                    

        

                                                       

                                                
 

                                    
 

                                           
                                                   

                                     
 

                         









                                                              





                                                                      
                                                                          

                                                                     
                                                      







                                                                   
                                                     
























                                                                      




                                        














                                                                        
                    















                                                                   
                                                  
                                    
                                                          



                                                                      




                                                                   

                                     









                                                                             

                                                              






                                                                  

















































































                                                                      
 










                                                   





















                                                                        


                                                                 












                                                                            

                                                          
                                                  
                                                         
                                    
               
                                                                        

        

                                                  
 



                                                                  






                                                    
                       
                                              
                                            
                                               

                                                                











                                                                          
                                       





                                                            
                                       








                                                                                              
                                                      

                                                                              

                                                              
 





                                            
 
                                         
                                                  













                                                                         
                                                                 


                                                         















                                                                                
                                                  


                                                                  
                                                                



                                                                             
                                                 





                                                                             







                                                                  





                                                                    
                                      






                                                       
                                               
                    
                                                    





                                   
                                      



                                                       
                                          
            
                                               

        








                                                                        


















































                                                                                                                                         



                                                                   
































                                                               
                                                  





                                                     


                                                       



                                         

                                              

                                                            


                                                            








                                                                            
                                                               
        











                                                                            
            













                                                           

                                                            


                                                             







                                                                               

                                                  
                                         
               
                                                                       
























                                                                        
                                                




                                 
                                                    










                                          

                                               

                                                       

                                                             



















                                                                                     
                                                                              
                                                   

                                                                                        


                                 








                                                                        
         

                           







                                              



                                               

                
                                       

        














                                                                        












                                                                       
 









                                                                                 















                                                                           





                                                                                  

                       

                                                     

                                                

                                              
 



                                                                         




                                             

                                                                           
                                       
 
                                                              
                                                  
            



                                                                                  

                       
 



                                                                   







                                                                       
                                                
                               

                                                                    

        









                                                                                                 








                                                                      
                                                               
                                       
                                                                        
                                                                                    
                                                                                   




















                                                                                 

                                                                                    





                                                                      

                                                                 

                                                                             






                                                                            
                                                           



                                                                                            




















                                                                      


                                                                           















                                                                 
                                                                    













                                                                        










                                                                               
               
                                             
                
                                                          
        
                                                                         
                                                    










                                                                         



                                                                       
 
















                                                            
                                                   
                                                          










                                                                      
                                                                                                
              

                                                                         







                                                                    
                    





                                                                      
 

                                                         











                                                                               

                                                                         

                                                         
                    





                                                                      
                                                        




                                                                     





                                                                                 


                                       
































                                                                                                 
                                                             













                                                                    
                       
                                          
                       
                                  
                       









                                                                     






                                          

                                                                         

















                                                                            

                                                               









                                                                             
                    








































































                                                                              

                                                         









                                                                             
                    


































































                                                                           
                                                         


















                                                                          
                                           
 


                                                  





                                                                      









                                                                               












                                                                 
                                                                                   


































                                                                                 


                                                      


                                                 

                                                   



















                                                                                        
                                                                          




                                                                    
                                                                          






                                                               
                                                                




                                                                 







                                                


                                      






                                                                            

                    























































                                                                                     








                                                                       

                                                                       




                            











                                                                    

                                                


                                               
                                           
       
 









                                                                
 









                                                               






































                                                                                  


                                                            
                                                      
                                      

                                                 
                                      


                                               


                                                                    

                                                                      


                                                       








                                                                         

                                                  

                                                        

                                                                                                                                                             

                                                               

                                       

                                                                
                                                                                      
                           

                                      

                               

                                                      



                                      

                                                                     

                                                                                                          

                                                                       
                              


                                                  

                                                                   

                                                           

                                                

                                  





                                           


                                                      


                                                                                                                                                               

                                                                 

                                                                                                             

                                                                           

                                                                

                                                             

                                                

                                               


                                                               

                                          





                                                                                                  





                                                                                    

                                                                    

                                                                

                                                               

                                                                


                                                                              

                                                                  

                                                                                               

                                 
 
                     
                                      
                       

                                                
 




                                                          
































































































































































                                                                              

                                                       
                                              
           
 

                                                
                    









                                                                      
 
                       
                        

                                                
                                                                             








                                                           
                        

                                                
                                                                             





                                                           
                                                                      











                                                                  


























                                                                  
 


                                            






                                                          
 













                                                           

                                                     
%% vim: tabstop=8:shiftwidth=4
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%
-module(asn1ct_check).

%% Main Module for ASN.1 compile time functions

%-compile(export_all).
-export([check/2,storeindb/2,format_error/1]).
%-define(debug,1).
-include("asn1_records.hrl").
%%% The tag-number for universal types
-define(N_BOOLEAN, 1). 
-define(N_INTEGER, 2). 
-define(N_BIT_STRING, 3).
-define(N_OCTET_STRING, 4).
-define(N_NULL, 5). 
-define(N_OBJECT_IDENTIFIER, 6). 
-define(N_OBJECT_DESCRIPTOR, 7). 
-define(N_EXTERNAL, 8). % constructed
-define(N_INSTANCE_OF,8).
-define(N_REAL, 9). 
-define(N_ENUMERATED, 10).   
-define(N_EMBEDDED_PDV, 11). % constructed
-define(N_UTF8String, 12).
-define('N_RELATIVE-OID',13).
-define(N_SEQUENCE, 16). 
-define(N_SET, 17). 
-define(N_NumericString, 18).
-define(N_PrintableString, 19).
-define(N_TeletexString, 20).
-define(N_VideotexString, 21).
-define(N_IA5String, 22).
-define(N_UTCTime, 23). 
-define(N_GeneralizedTime, 24). 
-define(N_GraphicString, 25).
-define(N_VisibleString, 26).
-define(N_GeneralString, 27).
-define(N_UniversalString, 28).
-define(N_CHARACTER_STRING, 29). % constructed
-define(N_BMPString, 30).

-define(TAG_PRIMITIVE(Num),
	#tag{class='UNIVERSAL',number=Num,type='IMPLICIT',form=0}).
-define(TAG_CONSTRUCTED(Num),
	#tag{class='UNIVERSAL',number=Num,type='IMPLICIT',form=32}).

-record(newt,{type=unchanged,tag=unchanged,constraint=unchanged,inlined=no}). % used in check_type to update type and tag
 
check(S,{Types,Values,ParameterizedTypes,Classes,Objects,ObjectSets}) ->
    %%Predicates used to filter errors
    TupleIs = fun({T,_},T) -> true;
		 (_,_) -> false
	      end,
    IsClass = fun(X) -> TupleIs(X,asn1_class) end,
    IsObjSet = fun(X) -> TupleIs(X,objectsetdef) end,
    IsPObjSet = fun(X) -> TupleIs(X,pobjectsetdef) end,
    IsObject = fun(X) -> TupleIs(X,objectdef) end,
    IsValueSet = fun(X) -> TupleIs(X,valueset) end,
    Element2 = fun(X) -> element(2,X) end,
    Element1 = fun(X) -> element(1,X) end,

    %% initialize internal book keeping
    save_asn1db_uptodate(S,S#state.erule,S#state.mname),
    put(top_module,S#state.mname),

    ParamError = checkp(S, ParameterizedTypes), %must do this before the templates are used
    
    %% table to save instances of parameterized objects,object sets
    asn1ct_table:new(parameterized_objects),
    asn1ct_table:new(inlined_objects),


    Terror = checkt(S, Types),
    ?dbg("checkt finished with errors:~n~p~n~n",[Terror]),

    %% get parameterized object sets sent to checkt/3
    %% and update Terror

    {PObjSetNames1,Terror2} = filter_errors(IsPObjSet,Terror),

    Verror = checkv(S, Values ++ ObjectSets), %value sets may be parsed as object sets
    ?dbg("checkv finished with errors:~n~p~n~n",[Verror]),
     %% get information object classes wrongly sent to checkt/3
     %% and update Terror2

    {AddClasses,Terror3} = filter_errors(IsClass,Terror2),

    NewClasses = Classes++AddClasses,

    Cerror = checkc(S, NewClasses),
    ?dbg("checkc finished with errors:~n~p~n~n",[Cerror]),
     %% get object sets incorrectly sent to checkv/3
     %% and update Verror

    {ObjSetNames,Verror2} = filter_errors(IsObjSet,Verror),

     %% get parameterized object sets incorrectly sent to checkv/3
     %% and update Verror2

    {PObjSetNames,Verror3} = filter_errors(IsPObjSet,Verror2),

     %% get objects incorrectly sent to checkv/3
     %% and update Verror3

    {ObjectNames,Verror4} = filter_errors(IsObject,Verror3),

    NewObjects = Objects++ObjectNames,
    NewObjectSets = ObjSetNames ++ PObjSetNames ++ PObjSetNames1,

     %% get value sets
     %% and update Verror4

    {ValueSetNames,Verror5} = filter_errors(IsValueSet,Verror4),

    {Oerror,ExclO,ExclOS} = checko(S,NewObjects ++
				   NewObjectSets,
				   [],[],[]),
    ?dbg("checko finished with errors:~n~p~n~n",[Oerror]),
    InlinedObjTuples = asn1ct_table:to_list(inlined_objects),
    InlinedObjects = lists:map(Element2,InlinedObjTuples),
    asn1ct_table:delete(inlined_objects),
    ParameterizedElems = asn1ct_table:to_list(parameterized_objects),
    ParObjectSets = lists:filter(fun({_OSName,objectset,_}) -> true;
				    (_)-> false end,ParameterizedElems),
    ParObjectSetNames = lists:map(Element1,ParObjectSets),
    ParTypes = lists:filter(fun({_TypeName,type,_}) -> true;
			       (_) -> false end, ParameterizedElems),
    ParTypesNames = lists:map(Element1,ParTypes),
    asn1ct_table:delete(parameterized_objects),
    put(asn1_reference,undefined),

    Exporterror = check_exports(S,S#state.module),
    ImportError = check_imports(S,S#state.module),

    AllErrors = lists:flatten([ParamError,Terror3,Verror5,Cerror,
			       Oerror,Exporterror,ImportError]),
    case AllErrors of
	[] ->
	    ContextSwitchTs = context_switch_in_spec(),
	    InstanceOf = instance_of_in_spec(S#state.mname),
	    NewTypes = lists:subtract(Types,AddClasses) ++ ContextSwitchTs
		++ InstanceOf ++ ParTypesNames,
	    NewValues = lists:subtract(Values,PObjSetNames++ObjectNames++
				       ValueSetNames),
	    {ok,
	     {NewTypes,NewValues,ParameterizedTypes,
	      NewClasses,NewObjects,NewObjectSets},
	     {NewTypes,NewValues,ParameterizedTypes,NewClasses,
	      lists:subtract(NewObjects,ExclO)++InlinedObjects,
	      lists:subtract(NewObjectSets,ExclOS)++ParObjectSetNames}};
	_ ->
	    {error,AllErrors}
    end.

context_switch_in_spec() ->
    L = [{external,'EXTERNAL'},
	 {embedded_pdv,'EMBEDDED PDV'},
	 {character_string,'CHARACTER STRING'}],
    F = fun({T,TName},Acc) ->
		case get(T) of
		    generate -> erase(T),
				[TName|Acc];
		    _ -> Acc
		end
	end,
    lists:foldl(F,[],L).

instance_of_in_spec(ModName) ->
    case get(instance_of) of
	L when is_list(L) ->
	    case lists:member(ModName,L) of
		true ->
		    erase(instance_of),
		    ['INSTANCE OF'];
		_ ->
		    erase(instance_of),
		    []
	    end;
	_ ->
	    []
    end.
instance_of_decl(ModName) ->
    Mods = get_instance_of(),
    case lists:member(ModName,Mods) of
	true ->
	    ok;
	_ ->
	    put(instance_of,[ModName|Mods])
    end.
get_instance_of() ->
    case get(instance_of) of
	undefined ->
	    [];
	L ->
	    L
    end.

put_once(T,State) ->
    %% state is one of undefined, unchecked, generate
    %% undefined > unchecked > generate
    case get(T) of
	PrevS when PrevS > State ->
	    put(T,State);
	_ ->
	    ok
    end.

filter_errors(Pred,ErrorList) ->
    Element2 = fun(X) -> element(2,X) end,
    RemovedTupleElements = lists:filter(Pred,ErrorList),
    RemovedNames = lists:map(Element2,RemovedTupleElements),
    %% remove value set name tuples from Verror
    RestErrors = lists:subtract(ErrorList,RemovedTupleElements),
    {RemovedNames,RestErrors}.

    
check_exports(S,Module = #module{}) ->
    case Module#module.exports of
	{exports,[]} ->
	    [];
	{exports,all} ->
	    [];
	{exports,ExportList} when is_list(ExportList) ->
	    IsNotDefined =
		fun(X) ->
			try
			    _ = get_referenced_type(S,X),
			    false
			catch {error,_} ->
				true
			end
		end,
	    [return_asn1_error(S, Ext, {undefined_export, Undef}) ||
		Ext = #'Externaltypereference'{type=Undef} <- ExportList,
		IsNotDefined(Ext)]
    end.

check_imports(S, #module{imports={imports,Imports}}) ->
    check_imports_1(S, Imports, []).

check_imports_1(_S, [], Acc) ->
    Acc;
check_imports_1(S, [#'SymbolsFromModule'{symbols=Imports,module=ModuleRef}|SFMs], Acc) ->
    Module = name_of_def(ModuleRef),
    Refs = [{try get_referenced_type(S, Ref)
	     catch throw:Error -> Error end,
	     Ref}
	    || Ref <- Imports],
    CreateError = fun(Ref) ->
			  Error = {undefined_import,name_of_def(Ref),Module},
			  return_asn1_error(S, Ref, Error)
		  end,
    Errors = [CreateError(Ref) || {{error, _}, Ref} <- Refs],
    check_imports_1(S, SFMs, Errors ++ Acc).

checkt(S0, Names) ->
    Check = fun do_checkt/3,

    %% NOTE: check_type/3 will store information in the process
    %% dictionary if context switching types are encountered;
    %% therefore we must force the evaluation order.
    Types = check_fold(S0, Names, Check),
    CtxtSwitch = check_contextswitchingtypes(S0, []),
    check_fold(S0, lists:reverse(CtxtSwitch), Check) ++ Types.

do_checkt(S, Name, #typedef{typespec=TypeSpec}=Type0) ->
    NewS = S#state{tname=Name},
    try check_type(NewS, Type0, TypeSpec) of
	#type{}=Ts ->
	    case Type0#typedef.checked of
		true ->			 %already checked and updated
		    ok;
		_ ->
		    Type = Type0#typedef{checked=true,
					 typespec=Ts},
		    asn1_db:dbput(NewS#state.mname,
				  Name, Type),
		    ok
	    end
    catch
	{error,Reason} ->
	    Reason;
	{asn1_class,_ClassDef} ->
	    {asn1_class,Name};
	pobjectsetdef ->
	    {pobjectsetdef,Name};
	pvalueset ->
	    {pvalueset,Name}
    end.

check_contextswitchingtypes(S,Acc) ->
    CSTList=[{external,'EXTERNAL'},
	     {embedded_pdv,'EMBEDDED PDV'},
	     {character_string,'CHARACTER STRING'}],
    check_contextswitchingtypes(S,CSTList,Acc).

check_contextswitchingtypes(S,[{T,TName}|Ts],Acc) ->
     case get(T) of
	unchecked ->
	    put(T,generate),
	    check_contextswitchingtypes(S,Ts,[TName|Acc]);
	_ ->
	    check_contextswitchingtypes(S,Ts,Acc)
     end;
check_contextswitchingtypes(_,[],Acc) ->
    Acc.

checkv(S, Names) ->
    check_fold(S, Names, fun do_checkv/3).

do_checkv(S, Name, Value)
  when is_record(Value, valuedef);
       is_record(Value, typedef); %Value set may be parsed as object set.
       is_record(Value, pvaluedef);
       is_record(Value, pvaluesetdef) ->
    try check_value(S, Value) of
	{valueset,VSet} ->
	    Pos = asn1ct:get_pos_of_def(Value),
	    CheckedVSDef = #typedef{checked=true,pos=Pos,
				    name=Name,typespec=VSet},
	    asn1_db:dbput(S#state.mname, Name, CheckedVSDef),
	    {valueset,Name};
	V ->
	    %% update the valuedef
	    asn1_db:dbput(S#state.mname, Name, V),
	    ok
    catch
	{error,Reason} ->
	    Reason;
	{pobjectsetdef} ->
	    {pobjectsetdef,Name};
	{objectsetdef} ->
	    {objectsetdef,Name};
	{asn1_class, _} ->
	    %% this is an object, save as typedef
	    #valuedef{checked=C,pos=Pos,name=N,type=Type,
		      value=Def} = Value,
	    ClassName = Type#type.def,
	    NewSpec = #'Object'{classname=ClassName,def=Def},
	    NewDef = #typedef{checked=C,pos=Pos,name=N,typespec=NewSpec},
	    asn1_db:dbput(S#state.mname, Name, NewDef),
	    {objectdef,Name}
    end.

%% Check parameterized types.
checkp(S, Names) ->
    check_fold(S, Names, fun do_checkp/3).

do_checkp(S0, Name, #ptypedef{typespec=TypeSpec}=Type0) ->
    S = S0#state{tname=Name},
    try check_ptype(S, Type0, TypeSpec) of
	#type{}=Ts ->
	    Type = Type0#ptypedef{checked=true,typespec=Ts},
	    asn1_db:dbput(S#state.mname, Name, Type),
	    ok
    catch
	{error,Reason} ->
	    Reason;
	{asn1_class,_ClassDef} ->
	    {asn1_class,Name};
	{asn1_param_class,_} ->
	    ok
    end.

%% Check class definitions.
checkc(S, Names) ->
    check_fold(S, Names, fun do_checkc/3).

do_checkc(S, Name, Class) ->
    try
	case is_classname(Name) of
	    false ->
		asn1_error(S, {illegal_class_name,Name});
	    true ->
		do_checkc_1(S, Name, Class)
	end
    catch {error,Reason} -> Reason
    end.

do_checkc_1(S, Name, #classdef{}=Class) ->
    C = check_class(S, Class),
    store_class(S, true, Class#classdef{typespec=C}, Name),
    ok;
do_checkc_1(S, Name, #typedef{typespec=#type{def=Def}=TS}) ->
    C = check_class(S, TS),
    {Mod,Pos} = case Def of
		    #'Externaltypereference'{module=M, pos=P} ->
			{M,P};
		    {pt, #'Externaltypereference'{module=M, pos=P}, _} ->
			{M,P}
		end,
    Class = #classdef{name=Name, typespec=C, pos=Pos, module=Mod},
    store_class(S, true, Class, Name),
    ok.

%% is_classname(Atom) -> true|false.
is_classname(Name) when is_atom(Name) ->
    lists:all(fun($-) -> true;
		 (D) when $0 =< D, D =< $9 -> true;
		 (UC) when $A =< UC, UC =< $Z -> true;
		 (_) -> false
	      end, atom_to_list(Name)).
    
checko(S0,[Name|Os],Acc,ExclO,ExclOS) ->
    Item = asn1_db:dbget(S0#state.mname, Name),
    S = S0#state{error_context=Item},
    try checko_1(S, Item, Name, ExclO, ExclOS) of
	{NewExclO,NewExclOS} ->
	    checko(S, Os, Acc, NewExclO, NewExclOS)
    catch
	throw:{error, Error} ->
	    checko(S, Os, [Error|Acc], ExclO, ExclOS)
    end;
checko(_S,[],Acc,ExclO,ExclOS) ->
    {lists:reverse(Acc),lists:reverse(ExclO),lists:reverse(ExclOS)}.

checko_1(S, #typedef{typespec=TS}=Object, Name, ExclO, ExclOS) ->
    NewS = S#state{tname=Name},
    O = check_object(NewS, Object, TS),
    NewObj = Object#typedef{checked=true,typespec=O},
    asn1_db:dbput(NewS#state.mname, Name, NewObj),
    case O of
	#'Object'{gen=true} ->
	    {ExclO,ExclOS};
	#'Object'{gen=false} ->
	    {[Name|ExclO],ExclOS};
	#'ObjectSet'{gen=true} ->
	    {ExclO,ExclOS};
	#'ObjectSet'{gen=false} ->
	    {ExclO,[Name|ExclOS]}
    end;
checko_1(S, #pobjectdef{}=PObject, Name, ExclO, ExclOS) ->
    NewS = S#state{tname=Name},
    PO = check_pobject(NewS, PObject),
    NewPObj = PObject#pobjectdef{def=PO},
    asn1_db:dbput(NewS#state.mname, Name, NewPObj),
    {[Name|ExclO],ExclOS};
checko_1(S, #pvaluesetdef{}=PObjSet, Name, ExclO, ExclOS) ->
    NewS = S#state{tname=Name},
    POS = check_pobjectset(NewS, PObjSet),
    asn1_db:dbput(NewS#state.mname, Name, POS),
    {ExclO,[Name|ExclOS]}.

check_class(S,CDef=#classdef{checked=Ch,name=Name,typespec=TS}) ->
    case Ch of
	true -> TS;
	idle -> TS;
	_ ->
	    store_class(S,idle,CDef,Name),
	    CheckedTS = check_class(S,TS),
	    store_class(S,true,CDef#classdef{typespec=CheckedTS},Name),
	    CheckedTS
    end;
check_class(S = #state{mname=M,tname=T},ClassSpec) 
  when is_record(ClassSpec,type) ->
    Def = ClassSpec#type.def,
    case Def of
	#'Externaltypereference'{module=M,type=T} ->
	    #objectclass{fields=Def}; % in case of recursive definitions
	Tref = #'Externaltypereference'{type=TName} ->
	    {MName,RefType} = get_referenced_type(S,Tref),
	    #classdef{} = CD = get_class_def(S, RefType),
	    NewState = update_state(S#state{tname=TName}, MName),
	    check_class(NewState, CD);
	{pt,ClassRef,Params} ->
	    %% parameterized class
	    {_,PClassDef} = get_referenced_type(S,ClassRef),
	    NewParaList = match_parameters(S, Params),
	    instantiate_pclass(S,PClassDef,NewParaList)
    end;
check_class(S, #objectclass{}=C) ->
    check_objectclass(S, C);
check_class(S,ClassName) ->
    {RefMod,Def} = get_referenced_type(S,ClassName),
    case Def of
	ClassDef when is_record(ClassDef,classdef) ->
	    case ClassDef#classdef.checked of
		true ->
		    ClassDef#classdef.typespec;
		idle ->
		    ClassDef#classdef.typespec;
		false ->
		    Name=ClassName#'Externaltypereference'.type,
		    store_class(S,idle,ClassDef,Name),
		    NewS = update_state(S#state{tname=Name}, RefMod),
		    CheckedTS = check_class(NewS,ClassDef#classdef.typespec),
		    store_class(S,true,ClassDef#classdef{typespec=CheckedTS},Name),
		    CheckedTS
	    end;
	TypeDef when is_record(TypeDef,typedef) ->
	    %% this case may occur when a definition is a reference 
	    %% to a class definition.
	    case TypeDef#typedef.typespec of
		#type{def=Ext} when is_record(Ext,'Externaltypereference') ->
		    check_class(S,Ext)
	    end
    end.

check_objectclass(S, #objectclass{fields=Fs0,syntax=Syntax0}=C) ->
    Fs = check_class_fields(S, Fs0),
    case Syntax0 of
	{'WITH SYNTAX',Syntax1} ->
	    Syntax = preprocess_syntax(S, Syntax1, Fs),
	    C#objectclass{fields=Fs,syntax={preprocessed_syntax,Syntax}};
	_ ->
	    C#objectclass{fields=Fs}
    end.

instantiate_pclass(S=#state{parameters=_OldArgs},PClassDef,Params) ->
    #ptypedef{args=Args,typespec=Type} = PClassDef,
    MatchedArgs = match_args(S,Args, Params, []),
    NewS = S#state{parameters=MatchedArgs,abscomppath=[]},
    check_class(NewS,#classdef{name=S#state.tname,typespec=Type}).

store_class(S,Mode,ClassDef,ClassName) ->
    NewCDef = ClassDef#classdef{checked=Mode},
    asn1_db:dbput(S#state.mname,ClassName,NewCDef).

check_class_fields(S,Fields) ->
    check_class_fields(S,Fields,[]).

check_class_fields(S,[F|Fields],Acc) ->
    NewField = 
	case element(1,F) of
	    fixedtypevaluefield ->
		{_,Name,Type,Unique,OSpec} = F,
		case {Unique,OSpec} of
		    {'UNIQUE',{'DEFAULT',_}} ->
			asn1_error(S, {unique_and_default,Name});
		    {_,_} ->
			ok
		end,
		RefType = check_type(S,#typedef{typespec=Type},Type),
		{fixedtypevaluefield,Name,RefType,Unique,OSpec};
	    object_or_fixedtypevalue_field ->
		{_,Name,Type,Unique,OSpec} = F,
		Type2 = maybe_unchecked_OCFT(S,Type),
		Cat = 
		    case asn1ct_gen:type(asn1ct_gen:get_inner(Type2#type.def)) of
			Def when is_record(Def,'Externaltypereference') ->
			    {_,D} = get_referenced_type(S, Def, true),
			    D;
			{undefined,user} -> 
			    %% neither of {primitive,bif} or {constructed,bif}
				    
			    {_,D} = get_referenced_type(S,#'Externaltypereference'{module=S#state.mname,type=Type#type.def}),
			    D;
			_ ->
			    Type
		    end,
		case Cat of
		    Class when is_record(Class,classdef) ->
			%% Type must be a referenced type => change it
			%% to an external reference.
			ToExt = fun(#type{def= CE = #'Externaltypereference'{}}) -> CE; (T) -> T end,
			{objectfield,Name,ToExt(Type),Unique,OSpec};
		    _ ->
			RefType = check_type(S,#typedef{typespec=Type},Type),	
			{fixedtypevaluefield,Name,RefType,Unique,OSpec}
		end;
	    objectset_or_fixedtypevalueset_field ->
		{_,Name,Type,OSpec} = F,
		RefType =
		    try check_type(S,#typedef{typespec=Type},Type) of
			#type{} = CheckedType ->
			    CheckedType
		    catch {asn1_class,_ClassDef} ->
			    case if_current_checked_type(S,Type) of
				true -> Type#type.def;
				_ ->    check_class(S,Type)
			    end
		    end,
		if
		    is_record(RefType,'Externaltypereference') ->
			{objectsetfield,Name,Type,OSpec};
		    is_record(RefType,classdef) ->
			{objectsetfield,Name,Type,OSpec};
		    is_record(RefType,objectclass) ->
			{objectsetfield,Name,Type,OSpec};
		    true ->
			{fixedtypevaluesetfield,Name,RefType,OSpec}
		end;
	    typefield ->
		case F of
		    {TF,Name,{'DEFAULT',Type}} ->
			{TF,Name,{'DEFAULT',check_type(S,#typedef{typespec=Type},Type)}};
		    _ -> F
		end;
	    _ -> F
	end,
    check_class_fields(S,Fields,[NewField|Acc]);
check_class_fields(_S,[],Acc) ->
    lists:reverse(Acc).

maybe_unchecked_OCFT(S,Type) ->
    case Type#type.def of
	#'ObjectClassFieldType'{type=undefined} ->
	    check_type(S,#typedef{typespec=Type},Type);
	_ ->
	    Type
    end.

if_current_checked_type(S,#type{def=Def}) ->
    CurrentModule = S#state.mname,
    CurrentCheckedName = S#state.tname,
    MergedModules = S#state.inputmodules,
 %   CurrentCheckedModule = S#state.mname,
    case Def of
	#'Externaltypereference'{module=CurrentModule,
				 type=CurrentCheckedName} ->
	    true;
	#'Externaltypereference'{module=ModuleName,
				 type=CurrentCheckedName} ->
	    case MergedModules of
		undefined ->
		    false;
		_ ->
		    lists:member(ModuleName,MergedModules)
	    end;
	_ ->
	    false
    end.

			  

check_pobject(_S,PObject) when is_record(PObject,pobjectdef) ->
    Def = PObject#pobjectdef.def,
    Def.
    

check_pobjectset(S,PObjSet) ->
    #pvaluesetdef{pos=Pos,name=Name,args=Args,type=Type,
		  valueset=ValueSet}=PObjSet,
    {Mod,Def} = get_referenced_type(S,Type#type.def),
    case Def of
	#classdef{} ->
	    ClassName = #'Externaltypereference'{module=Mod,
						 type=get_datastr_name(Def)},
	    {valueset,Set} = ValueSet,
%	    ObjectSet = #'ObjectSet'{class={objectclassname,ClassName},
	    ObjectSet = #'ObjectSet'{class=ClassName,
				     set=Set},
	    #pobjectsetdef{pos=Pos,name=Name,args=Args,class=Type#type.def,
			   def=ObjectSet};
	_ ->
	    PObjSet
    end.

-record(osi,					%Object set information.
	{st,
	 classref,
	 uniq,
	 ext
	}).

check_object(_S,ObjDef,ObjSpec) when (ObjDef#typedef.checked == true) ->
    ObjSpec;
check_object(S,_ObjDef,#'Object'{classname=ClassRef,def=ObjectDef}) ->
    ?dbg("check_object ~p~n",[ObjectDef]),
    _ = check_externaltypereference(S,ClassRef),
    {ClassDef, NewClassRef} =
	case get_referenced_type(S, ClassRef, true) of
	    {MName,#classdef{checked=false, name=CLName}=ClDef} ->
		Type = ClassRef#'Externaltypereference'.type,
		NewState = update_state(S#state{tname=Type}, MName),
		ObjClass = check_class(NewState, ClDef),
		{ClDef#classdef{checked=true, typespec=ObjClass},
		 #'Externaltypereference'{module=MName, type=CLName}};
	    {MName,#classdef{name=CLName}=ClDef} ->
		{ClDef, #'Externaltypereference'{module=MName, type=CLName}};
	    _ ->
		asn1_error(S, illegal_object)
	end,
    NewObj =
	case ObjectDef of
	    {object,_,_}=Def ->
		NewSettingList = check_objectdefn(S,Def,ClassDef),
		#'Object'{def=NewSettingList};
	    {po,{object,DefObj},ArgsList} ->
		{_,Object} = get_referenced_type(S,DefObj),%DefObj is a 
		%%#'Externalvaluereference' or a #'Externaltypereference'
		%% Maybe this call should be catched and in case of an exception
		%% a not initialized parameterized object should be returned.
		instantiate_po(S,ClassDef,Object,ArgsList);
	    {pv,{simpledefinedvalue,ObjRef},ArgList} ->
		{_,Object} = get_referenced_type(S,ObjRef),
		instantiate_po(S,ClassDef,Object,ArgList);
	    #'Externalvaluereference'{} ->
		{_,Object} = get_referenced_type(S,ObjectDef),
		check_object(S, Object, object_to_check(S, Object));
	    [] -> 
		%% An object with no fields (parsed as a value).
		Def = {object,defaultsyntax,[]},
		NewSettingList = check_objectdefn(S, Def, ClassDef),
		#'Object'{def=NewSettingList};
	    _ ->
		asn1_error(S, illegal_object)
	end,
    Fields = (ClassDef#classdef.typespec)#objectclass.fields,
    Gen = gen_incl(S,NewObj#'Object'.def, Fields),
    NewObj#'Object'{classname=NewClassRef,gen=Gen};
check_object(S, _, #'ObjectSet'{class=ClassRef0,set=Set0}=ObjSet0) ->
    {_,ClassDef} = get_referenced_type(S, ClassRef0),
    ClassRef = check_externaltypereference(S, ClassRef0),
    {UniqueFieldName,UniqueInfo} =
	case get_unique_fieldname(S, ClassDef) of
	    no_unique -> {{unique,undefined},{unique,undefined}};
	    Other -> {element(1,Other),Other}
	end,
    OSI0 = #osi{st=S,classref=ClassRef,uniq=UniqueInfo,ext=false},
    {Set1,OSI1} = if
		      is_list(Set0) ->
			  check_object_set_list(Set0, OSI0);
		      true ->
			  check_object_set(Set0, OSI0)
		  end,
    Ext = case Set1 of
	      [] ->
		  %% FIXME: X420 does not compile unless we force
		  %% empty sets to be extensible. There should be
		  %% a better way.
		  true;
	      [_|_] ->
		  OSI1#osi.ext
	  end,
    Set2 = remove_duplicate_objects(S, Set1),
    Set = case Ext of
	      false -> Set2;
	      true -> Set2 ++ ['EXTENSIONMARK']
	  end,
    ObjSet = ObjSet0#'ObjectSet'{uniquefname=UniqueFieldName,set=Set},
    Gen = gen_incl_set(S, Set, ClassDef),
    ObjSet#'ObjectSet'{class=ClassRef,gen=Gen}.

check_object_set({element_set,Root0,Ext0}, OSI0) ->
    OSI = case Ext0 of
	      none -> OSI0;
	      _ -> OSI0#osi{ext=true}
	  end,
    case {Root0,Ext0} of
	{empty,empty} -> {[],OSI};
	{empty,Ext} -> check_object_set(Ext, OSI);
	{Root,none} -> check_object_set(Root, OSI);
	{Root,empty} -> check_object_set(Root, OSI);
	{Root,Ext} -> check_object_set_list([Root,Ext], OSI)
    end;
check_object_set(#'Externaltypereference'{}=Ref, #osi{st=S}=OSI) ->
    {_,#typedef{typespec=OSdef}=OS} = get_referenced_type(S, Ref),
    ObjectSet = check_object(S, OS, OSdef),
    check_object_set_objset(ObjectSet, OSI);
check_object_set(#'Externalvaluereference'{}=Ref, #osi{st=S}=OSI) ->
    {RefedMod,ObjName,#'Object'{def=Def}} = check_referenced_object(S, Ref),
    ObjList = check_object_set_mk(RefedMod, ObjName, Def, OSI),
    {ObjList,OSI};
check_object_set({'EXCEPT',Incl0,Excl0}, OSI) ->
    {Incl1,_} = check_object_set(Incl0, OSI),
    {Excl1,_} = check_object_set(Excl0, OSI),
    Exclude = sofs:set([N || {N,_} <- Excl1], [name]),
    Incl2 = [{Name,Obj} || {Name,_,_}=Obj <- Incl1],
    Incl3 = sofs:relation(Incl2, [{name,object}]),
    Incl4 = sofs:drestriction(Incl3, Exclude),
    Incl5 = sofs:to_external(Incl4),
    Incl = [Obj || {_,Obj} <- Incl5],
    {Incl,OSI};
check_object_set({object,_,_}=Obj0, OSI) ->
    #osi{st=S,classref=ClassRef} = OSI,
    #'Object'{def=Def} =
	check_object(S, #typedef{typespec=Obj0},
		     #'Object'{classname=ClassRef,def=Obj0}),
    ObjList = check_object_set_mk(Def, OSI),
    {ObjList,OSI};
check_object_set(#'ObjectClassFieldType'{classname=ObjName,
					 fieldname=FieldNames},
		 #osi{st=S}=OSI) ->
    Set = check_ObjectSetFromObjects(S, ObjName, FieldNames),
    check_object_set_objset_list(Set, OSI);
check_object_set({'ObjectSetFromObjects',Obj,FieldNames}, #osi{st=S}=OSI) ->
    ObjName = element(tuple_size(Obj), Obj),
    Set = check_ObjectSetFromObjects(S, ObjName, FieldNames),
    check_object_set_objset_list(Set, OSI);
check_object_set({pt,DefinedObjSet,ParamList0}, OSI) ->
    #osi{st=S,classref=ClassRef} = OSI,
    {_,PObjSetDef} = get_referenced_type(S, DefinedObjSet),
    ParamList = match_parameters(S, ParamList0),
    ObjectSet = instantiate_pos(S, ClassRef, PObjSetDef, ParamList),
    check_object_set_objset(ObjectSet, OSI);
check_object_set({pos,{objectset,_,DefinedObjSet},Params0}, OSI) ->
    #osi{st=S,classref=ClassRef} = OSI,
    {_,PObjSetDef} = get_referenced_type(S, DefinedObjSet),
    Params = match_parameters(S, Params0),
    ObjectSet = instantiate_pos(S, ClassRef, PObjSetDef, Params),
    check_object_set_objset(ObjectSet, OSI);
check_object_set({pv,{simpledefinedvalue,DefinedObject},Params}=PV, OSI) ->
    #osi{st=S,classref=ClassRef} = OSI,
    Args = match_parameters(S, Params),
    #'Object'{def=Def} =
	check_object(S, PV,
		     #'Object'{classname=ClassRef ,
			       def={po,{object,DefinedObject},Args}}),
    ObjList = check_object_set_mk(Def, OSI),
    {ObjList,OSI};
check_object_set({'SingleValue',Val}, OSI) ->
    check_object_set(Val, OSI);
check_object_set({'ValueFromObject',{object,Object},FieldNames}, OSI) ->
    #osi{st=S} = OSI,
    case extract_field(S, Object, FieldNames) of
	#'Object'{def=Def} ->
	    ObjList = check_object_set_mk(Def, OSI),
	    {ObjList,OSI};
	_ ->
	    asn1_error(S, illegal_object)
    end;
check_object_set(#type{def=Def}, OSI) ->
    check_object_set(Def, OSI);
check_object_set({union,A0,B0}, OSI0) ->
    {A,OSI1} = check_object_set(A0, OSI0),
    {B,OSI} = check_object_set(B0, OSI1),
    {A++B,OSI}.

check_object_set_list([H|T], OSI0) ->
    {Set0,OSI1} = check_object_set(H, OSI0),
    {Set1,OSI2} = check_object_set_list(T, OSI1),
    {Set0++Set1,OSI2};
check_object_set_list([], OSI) ->
    {[],OSI}.

check_object_set_objset(#'ObjectSet'{set=Set}, OSI) ->
    check_object_set_objset_list(Set, OSI).

check_object_set_objset_list(Set, OSI) ->
    check_object_set_objset_list_1(Set, OSI, []).

check_object_set_objset_list_1(['EXTENSIONMARK'|T], OSI, Acc) ->
    check_object_set_objset_list_1(T, OSI#osi{ext=true}, Acc);
check_object_set_objset_list_1([H|T], OSI, Acc) ->
    check_object_set_objset_list_1(T, OSI, [H|Acc]);
check_object_set_objset_list_1([], OSI, Acc) ->
    {Acc,OSI}.

check_object_set_mk(Fields, OSI) ->
    check_object_set_mk(no_mod, no_name, Fields, OSI).

check_object_set_mk(M, N, Def, #osi{uniq={unique,undefined}}) ->
    {_,_,Fields} = Def,
    [{{M,N},no_unique_value,Fields}];
check_object_set_mk(M, N, Def, #osi{uniq={UniqField,_}}) ->
    {_,_,Fields} = Def,
    case lists:keyfind(UniqField, 1, Fields) of
	{UniqField,#valuedef{value=Val}} ->
	    [{{M,N},Val,Fields}];
	false ->
	    case Fields of
		[{_,#typedef{typespec=#'ObjectSet'{set=['EXTENSIONMARK']}}}] ->
		    %% FIXME: If object is missing the unique field and
		    %% only contains a reference to an empty object set,
		    %% we will remove the entire object as a workaround
		    %% to get X420 to compile. There should be a better
		    %% way.
		    [];
		_ ->
		    [{{M,N},no_unique_value,Fields}]
	    end
    end.

%% remove_duplicate_objects/1 remove duplicates of objects.
%% For instance may Set contain objects of same class from
%% different object sets that in fact might be duplicates.
remove_duplicate_objects(S, Set0) when is_list(Set0) ->
    Set1 = [{Id,Orig} || {_,Id,_}=Orig <- Set0],
    Set2 = sofs:relation(Set1),
    Set3 = sofs:relation_to_family(Set2),
    Set = sofs:to_external(Set3),
    remove_duplicate_objects_1(S, Set).

remove_duplicate_objects_1(S, [{no_unique_value,Objs}|T]) ->
    Objs ++ remove_duplicate_objects_1(S, T);
remove_duplicate_objects_1(S, [{_,[_]=Objs}|T]) ->
    Objs ++ remove_duplicate_objects_1(S, T);
remove_duplicate_objects_1(S, [{Id,[_|_]=Objs}|T]) ->
    MakeSortable = fun(What) -> sortable_type(S, What) end,
    Tagged = order_tag_set(Objs, MakeSortable),
    case lists:ukeysort(1, Tagged) of
	[{_,Obj}] ->
	    [Obj|remove_duplicate_objects_1(S, T)];
	[_|_] ->
	    asn1_error(S, {non_unique_object,Id})
    end;
remove_duplicate_objects_1(_, []) ->
    [].

order_tag_set([{_, _, Fields}=Orig|Fs], Fun) ->
    Pair = {[{FId, traverse(F, Fun)} || {FId, F} <- Fields], Orig},
    [Pair|order_tag_set(Fs, Fun)];
order_tag_set([], _) -> [].

sortable_type(S, #'Externaltypereference'{}=ERef) ->
    try get_referenced_type(S, ERef) of
	 {_,#typedef{}=OI} ->
	    OI#typedef{pos=undefined,name=undefined}
    catch
	_:_ ->
	    ERef
    end;
sortable_type(_, #typedef{}=TD) ->
    asn1ct:unset_pos_mod(TD#typedef{name=undefined});
sortable_type(_, Type) ->
    asn1ct:unset_pos_mod(Type).

traverse(Structure0, Fun) ->
    Structure = Fun(Structure0),
    traverse_1(Structure, Fun).

traverse_1(#typedef{typespec=TS0} = TD, Fun) ->
    TS = traverse(TS0, Fun),
    TD#typedef{typespec=TS};
traverse_1(#valuedef{type=TS0} = VD, Fun) ->
    TS = traverse(TS0, Fun),
    VD#valuedef{type=TS};
traverse_1(#type{def=TS0} = TD, Fun) ->
    TS = traverse(TS0, Fun),
    TD#type{def=TS};
traverse_1(#'SEQUENCE'{components=Cs0} = Seq, Fun) ->
    Cs = traverse_seq_set(Cs0, Fun),
    Seq#'SEQUENCE'{components=Cs};
traverse_1({'SEQUENCE OF',Type0}, Fun) ->
    Type = traverse(Type0, Fun),
    {'SEQUENCE OF',Type};
traverse_1({'SET OF',Type0}, Fun) ->
    Type = traverse(Type0, Fun),
    {'SET OF',Type};
traverse_1(#'SET'{components=Cs0} = Set, Fun) ->
    Cs = traverse_seq_set(Cs0, Fun),
    Set#'SET'{components=Cs};
traverse_1({'CHOICE', Cs0}, Fun) ->
    Cs = traverse_seq_set(Cs0, Fun),
    {'CHOICE', Cs};
traverse_1(Leaf, _) ->
    Leaf.

traverse_seq_set(List, Fun) when is_list(List) ->
    traverse_seq_set_1(List, Fun);
traverse_seq_set({Set, Ext}, Fun) ->
    {traverse_seq_set_1(Set, Fun), traverse_seq_set_1(Ext, Fun)};
traverse_seq_set({Set1, Set2, Set3}, Fun) ->
    {traverse_seq_set_1(Set1, Fun),
     traverse_seq_set_1(Set2, Fun),
     traverse_seq_set_1(Set3, Fun)}.

traverse_seq_set_1([#'ComponentType'{} = CT0|Cs], Fun) ->
    CT = #'ComponentType'{typespec=TS0} = Fun(CT0),
    TS = traverse(TS0, Fun),
    [CT#'ComponentType'{typespec=TS}|traverse_seq_set_1(Cs, Fun)];
traverse_seq_set_1([{'COMPONENTS OF', _} = CO0|Cs], Fun) ->
    {'COMPONENTS OF', TS0} = Fun(CO0),
    TS = traverse(TS0, Fun),
    [{'COMPONENTS OF', TS}|traverse_seq_set_1(Cs, Fun)];
traverse_seq_set_1([], _) ->
    [].

object_to_check(_, #typedef{typespec=ObjDef}) ->
    ObjDef;
object_to_check(S, #valuedef{type=Class,value=ObjectRef}) ->
    %% If the object definition is parsed as an object the ClassName
    %% is parsed as a type.
    case Class of
	#type{def=#'Externaltypereference'{}=Def} ->
	    #'Object'{classname=Def,def=ObjectRef};
	_ ->
	    asn1_error(S, illegal_object)
    end.

check_referenced_object(S,ObjRef) 
  when is_record(ObjRef,'Externalvaluereference')->
    case get_referenced_type(S,ObjRef) of
	{RefedMod,ObjectDef} when is_record(ObjectDef,valuedef) ->	
	    ?dbg("Externalvaluereference, ObjectDef: ~p~n",[ObjectDef]),
	    #type{def=ClassRef} = ObjectDef#valuedef.type,
	    Def = ObjectDef#valuedef.value,
	    {RefedMod,get_datastr_name(ObjectDef),
	     check_object(update_state(S,RefedMod),ObjectDef,#'Object'{classname=ClassRef,
						def=Def})};
	{RefedMod,ObjectDef} when is_record(ObjectDef,typedef) ->
	    {RefedMod,get_datastr_name(ObjectDef),
	     check_object(update_state(S,RefedMod),ObjectDef,ObjectDef#typedef.typespec)}
    end.

check_ObjectSetFromObjects(S, ObjName, Fields) ->
    {_,Obj0} = get_referenced_type(S, ObjName),
    case check_object(S, Obj0, Obj0#typedef.typespec) of
	#'ObjectSet'{}=Obj1 ->
	    get_fieldname_set(S, Obj1, Fields);
	#'Object'{classname=Class,
		  def={object,_,ObjFs}} ->
	    ObjSet = #'ObjectSet'{class=Class,
				  set=[{'_','_',ObjFs}]},
	    get_fieldname_set(S, ObjSet, Fields)
    end.

%%  get_type_from_object(State, ObjectOrObjectSet, [{RefType,FieldName}]) ->
%%    Type
get_type_from_object(S, Object, FieldNames)
  when is_record(Object, 'Externaltypereference');
       is_record(Object, 'Externalvaluereference') ->
    extract_field(S, Object, FieldNames).

%% get_value_from_object(State, ObjectOrObjectSet, [{RefType,FieldName}]) ->
%%    UntaggedValue
get_value_from_object(S, Def, FieldNames) ->
    case extract_field(S, Def, FieldNames) of
	#valuedef{value=Val} ->
	    Val;
	{valueset,_}=Val ->
	    Val;
	_ ->
	    asn1_error(S, illegal_value)
    end.

%% extract_field(State, ObjectOrObjectSet, [{RefType,FieldName}])
%%   RefType = typefieldreference | valuefieldreference
%%
%%   Get the type, value, object, object set, or value set from the
%%   referenced object or object set. The list of field name tuples
%%   may have more than one element.  All field names but the last
%%   refers to either an object or object set.

extract_field(S, Def0, FieldNames) ->
    {_,Def1} = get_referenced_type(S, Def0),
    Def2 = check_object(S, Def1, Def1#typedef.typespec),
    Def = Def1#typedef{typespec=Def2},
    get_fieldname_element(S, Def, FieldNames).

%% get_fieldname_element(State, Element, [{RefType,FieldName}]
%%   RefType = typefieldreference | valuefieldreference
%%
%%   Get the type, value, object, object set, or value set from the referenced
%%   element. The list of field name tuples may have more than one element.
%%   All field names but the last refers to either an object or object set.

get_fieldname_element(S, Object0, [{_RefType,FieldName}|Fields]) ->
    Object = case Object0 of
		 #typedef{typespec=#'Object'{def=Obj}} -> Obj;
		 {_,_,_}=Obj -> Obj
	     end,
    case check_fieldname_element(S, FieldName, Object) of
	#'Object'{def=D} when Fields =/= [] ->
	    get_fieldname_element(S, D, Fields);
	#'ObjectSet'{}=Set ->
	    get_fieldname_set(S, Set, Fields);
	Result when Fields =:= [] ->
	    Result
    end;
get_fieldname_element(_S, Def, []) ->
    Def.

get_fieldname_set(S, #'ObjectSet'{set=Set0}, T) ->
    get_fieldname_set_1(S, Set0, T, []).

get_fieldname_set_1(S, ['EXTENSIONMARK'=Ext|T], Fields, Acc) ->
    get_fieldname_set_1(S, T, Fields, [Ext|Acc]);
get_fieldname_set_1(S, [H|T], Fields, Acc) ->
    try get_fieldname_element(S, H, Fields) of
	L when is_list(L) ->
	    get_fieldname_set_1(S, T, Fields, L++Acc);
	{valueset,L} ->
	    get_fieldname_set_1(S, T, Fields, L++Acc);
	Other ->
	    get_fieldname_set_1(S, T, Fields, [Other|Acc])
    catch
	throw:{error,_} ->
	    get_fieldname_set_1(S, T, Fields, Acc)
    end;
get_fieldname_set_1(_, [], _Fields, Acc) ->
    case Acc of
	[#valuedef{}|_] ->
	    {valueset,Acc};
	_ ->
	    Acc
    end.

check_fieldname_element(S, Name, {_,_,Fields}) ->
    case lists:keyfind(Name, 1, Fields) of
	{Name,Def} ->
	    check_fieldname_element_1(S, Def);
	false ->
	    asn1_error(S, {undefined_field,Name})
    end.

check_fieldname_element_1(S, #typedef{typespec=Ts}=TDef) ->
    case Ts of
	#'Object'{} ->
	    check_object(S, TDef, Ts);
	_ ->
	    check_type(S, TDef, Ts)
    end;
check_fieldname_element_1(S, #valuedef{}=VDef) ->
    try
	check_value(S, VDef)
    catch
	throw:{asn1_class, _} ->
	    #valuedef{checked=C,pos=Pos,name=N,type=Type,
		      value=Def} = VDef,
	    ClassName = Type#type.def,
	    NewSpec = #'Object'{classname=ClassName,def=Def},
	    NewDef = #typedef{checked=C,pos=Pos,name=N,typespec=NewSpec},
	    check_fieldname_element_1(S, NewDef)
    end;
check_fieldname_element_1(_S, {value_tag,Val}) ->
    #valuedef{value=Val};
check_fieldname_element_1(S, Eref)
  when is_record(Eref, 'Externaltypereference');
       is_record(Eref, 'Externalvaluereference') ->
    {_,TDef} = get_referenced_type(S, Eref),
    check_fieldname_element_1(S, TDef).
    
%% instantiate_po/4
%% ClassDef is the class of Object,
%% Object is the Parameterized object, which is referenced,
%% ArgsList is the list of actual parameters
%% returns an #'Object' record.
instantiate_po(S=#state{parameters=_OldArgs},_ClassDef,Object,ArgsList) when is_record(Object,pobjectdef) ->
    FormalParams = get_pt_args(Object),
    MatchedArgs = match_args(S,FormalParams,ArgsList,[]),
    NewS = S#state{parameters=MatchedArgs},
    check_object(NewS,Object,#'Object'{classname=Object#pobjectdef.class,
				    def=Object#pobjectdef.def}).

%% instantiate_pos/4
%% ClassDef is the class of ObjectSetDef,
%% ObjectSetDef is the Parameterized object set, which is referenced 
%% on the right side of the assignment,
%% ArgsList is the list of actual parameters, i.e. real objects
instantiate_pos(S=#state{parameters=_OldArgs},ClassRef,ObjectSetDef,ArgsList) ->
    FormalParams = get_pt_args(ObjectSetDef),
    OSet = case get_pt_spec(ObjectSetDef) of
	       {valueset,Set} -> #'ObjectSet'{class=ClassRef,set=Set};
	       Set when is_record(Set,'ObjectSet') -> Set;
	       _ -> asn1_error(S, invalid_objectset)
	   end,
    MatchedArgs = match_args(S,FormalParams,ArgsList,[]),
    NewS = S#state{parameters=MatchedArgs},
    check_object(NewS,ObjectSetDef,OSet).

    
%% gen_incl -> boolean()
%% If object with Fields has any of the corresponding class' typefields
%% then return value is true otherwise it is false.
%% If an object lacks a typefield but the class has a type field that
%% is OPTIONAL then we want gen to be true
gen_incl(S,{_,_,Fields},CFields)->
    gen_incl1(S,Fields,CFields).

gen_incl1(_,_,[]) ->
    false;
gen_incl1(S,Fields,[C|CFields]) ->
    case element(1,C) of
	typefield ->
	    true; %% should check that field is OPTIONAL or DEFUALT if
                  %% the object lacks this field
	objectfield ->
	    case lists:keysearch(element(2,C),1,Fields) of
		{value,Field} ->
		    ClassRef = case element(3,C) of
			      #type{def=Ref} -> Ref;
			      Eref when is_record(Eref,'Externaltypereference') ->
				  Eref
			  end,
		    ClassFields = get_objclass_fields(S,ClassRef),
		    ObjDef = 
			case element(2,Field) of
			    TDef when is_record(TDef,typedef) -> 
				check_object(S,TDef,TDef#typedef.typespec);
			    ERef ->
				{_,T} = get_referenced_type(S,ERef),
				check_object(S, T, object_to_check(S, T))
			end,
		    case gen_incl(S,ObjDef#'Object'.def,
				  ClassFields) of
			true ->
			    true;
			_ ->
			    gen_incl1(S,Fields,CFields)
		    end;
		_ ->
		    gen_incl1(S,Fields,CFields)
	    end;
	_ -> 
	    gen_incl1(S,Fields,CFields)
    end.

get_objclass_fields(S,Eref=#'Externaltypereference'{}) ->
    {_,ClassDef} = get_referenced_type(S,Eref, true),
    get_objclass_fields(S,ClassDef);
get_objclass_fields(S,CD=#classdef{typespec=#'Externaltypereference'{}}) ->
    get_objclass_fields(S,CD#classdef.typespec);
get_objclass_fields(_,#classdef{typespec=CDef}) 
  when is_record(CDef,objectclass) ->
    CDef#objectclass.fields.
    

%% first if no unique field in the class return false.(don't generate code)
gen_incl_set(S,Fields,#typedef{typespec=#type{def=Eref}}) 
  when is_record(Eref,'Externaltypereference') ->
    %% When a Defined class is a reference toanother class definition
    {_,CDef} = get_referenced_type(S,Eref),
    gen_incl_set(S,Fields,CDef);
gen_incl_set(S,Fields,ClassDef) ->
    case get_unique_fieldname(S, ClassDef) of
	no_unique ->
	    false;
	{_, _} ->
	    gen_incl_set1(S,Fields,
			  (ClassDef#classdef.typespec)#objectclass.fields)
    end.


%% if any of the existing or potentially existing objects has a typefield
%% then return true.
gen_incl_set1(_,[],_CFields)->
    false;
gen_incl_set1(_,['EXTENSIONMARK'],_) ->
    true;
%% Fields are the fields of an object in the object set.
%% CFields are the fields of the class of the object set.
gen_incl_set1(_,['EXTENSIONMARK'|_],_) ->
    true;
gen_incl_set1(S,[Object|Rest],CFields)->
    Fields = element(tuple_size(Object), Object),
    case gen_incl1(S,Fields,CFields) of
	true ->
	    true;
	false ->
	    gen_incl_set1(S,Rest,CFields)
    end.


%%%
%%% Check an object definition.
%%%

check_objectdefn(S, Def, #classdef{typespec=ObjClass}) ->
    #objectclass{syntax=Syntax0,fields=ClassFields} = ObjClass,
    case Def of
	{object,defaultsyntax,Fields} ->
	    check_defaultfields(S, Fields, ClassFields);
	{object,definedsyntax,Fields} ->
	    Syntax = get_syntax(S, Syntax0, ClassFields),
	    case match_syntax(S, Syntax, Fields, []) of
		{match,NewFields,[]} ->
		    {object,defaultsyntax,NewFields};
		{match,_,[What|_]} ->
		    syntax_match_error(S, What);
		{nomatch,[What|_]} ->
		    syntax_match_error(S, What);
		{nomatch,[]} ->
		    syntax_match_error(S)
	    end
    end.


%%%
%%% Pre-process the simplified syntax so that it can be more
%%% easily matched.
%%%

get_syntax(_, {preprocessed_syntax,Syntax}, _) ->
    Syntax;
get_syntax(S, {'WITH SYNTAX',Syntax}, ClassFields) ->
    preprocess_syntax(S, Syntax, ClassFields).

preprocess_syntax(S, Syntax0, Cs) ->
    Syntax = preprocess_syntax_1(S, Syntax0, Cs, true),
    Present0 = preprocess_get_fields(Syntax, []),
    Present1 = lists:sort(Present0),
    Present = ordsets:from_list(Present1),
    case Present =:= Present1 of
	false ->
	    Dupl = Present1 -- Present,
	    asn1_error(S, {syntax_duplicated_fields,Dupl});
	true ->
	    ok
    end,
    Mandatory0 = get_mandatory_class_fields(Cs),
    Mandatory = ordsets:from_list(Mandatory0),
    case ordsets:subtract(Mandatory, Present) of
	[] ->
	    Syntax;
	[_|_]=Missing ->
	    asn1_error(S, {syntax_missing_mandatory_fields,Missing})
    end.

preprocess_syntax_1(S, [H|T], Cs, Mandatory) when is_list(H) ->
    [{optional,preprocess_syntax_1(S, H, Cs, false)}|
     preprocess_syntax_1(S, T, Cs, Mandatory)];
preprocess_syntax_1(S, [{valuefieldreference,Name}|T], Cs, Mandatory) ->
    F = preprocess_check_field(S, Name, Cs, Mandatory),
    [F|preprocess_syntax_1(S, T, Cs, Mandatory)];
preprocess_syntax_1(S, [{typefieldreference,Name}|T], Cs, Mandatory) ->
    F = preprocess_check_field(S, Name, Cs, Mandatory),
    [F|preprocess_syntax_1(S, T, Cs, Mandatory)];
preprocess_syntax_1(S,[{Token,_}|T], Cs, Mandatory) when is_atom(Token) ->
    [{token,Token}|preprocess_syntax_1(S, T, Cs, Mandatory)];
preprocess_syntax_1(S, [Token|T], Cs, Mandatory) when is_atom(Token) ->
    [{token,Token}|preprocess_syntax_1(S, T, Cs, Mandatory)];
preprocess_syntax_1(_, [], _, _) -> [].

preprocess_check_field(S, Name, Cs, Mandatory) ->
    case lists:keyfind(Name, 2, Cs) of
	Tuple when is_tuple(Tuple) ->
	    case not Mandatory andalso is_mandatory_class_field(Tuple) of
		true ->
		    asn1_error(S, {syntax_mandatory_in_optional_group,Name});
		false ->
		    {field,Tuple}
	    end;
	false ->
	    asn1_error(S, {syntax_undefined_field,Name})
    end.

preprocess_get_fields([{field,F}|T], Acc) ->
    Name = element(2, F),
    preprocess_get_fields(T, [Name|Acc]);
preprocess_get_fields([{optional,L}|T], Acc) ->
    preprocess_get_fields(T, preprocess_get_fields(L, Acc));
preprocess_get_fields([_|T], Acc) ->
    preprocess_get_fields(T, Acc);
preprocess_get_fields([], Acc) ->
    Acc.

%%%
%%% Match the actual fields in the object definition to
%%% the pre-processed simplified syntax.
%%%

match_syntax(S, [{token,Token}|T], [A|As]=Args, Acc) ->
    case A of
	{word_or_setting,_,#'Externaltypereference'{type=Token}} ->
	    match_syntax(S, T, As, Acc);
	{Token,Line} when is_integer(Line) ->
	    match_syntax(S, T, As, Acc);
	_ ->
	    {nomatch,Args}
    end;
match_syntax(S, [{field,Field}|T]=Fs, [A|As0]=Args0, Acc) ->
    try match_syntax_type(S, Field, A) of
	{match,Match} ->
	    match_syntax(S, T, As0, lists:reverse(Match)++Acc);
	{params,_Name,#ptypedef{args=Params}=P,Ref} ->
	    {Args,As} = lists:split(length(Params), As0),
	    Val = match_syntax_params(S, P, Ref, Args),
	    match_syntax(S, Fs, [Val|As], Acc)
    catch
	_:_ ->
	    {nomatch,Args0}
    end;
match_syntax(S, [{optional,L}|T], As0, Acc)         ->
    case match_syntax(S, L, As0, []) of
	{match,Match,As} ->
	    match_syntax(S, T, As, lists:reverse(Match)++Acc);
	{nomatch,As0} ->
	    match_syntax(S, T, As0, Acc);
	{nomatch,_}=NoMatch ->
	    NoMatch
    end;
match_syntax(_, [_|_], [], _Acc)                    ->
    {nomatch,[]};
match_syntax(_, [], As, Acc)                        ->
    {match,Acc,As}.

match_syntax_type(S, Type, {value_tag,Val})         ->
    match_syntax_type(S, Type, Val);
match_syntax_type(S, Type, {setting,_,Val})         ->
    match_syntax_type(S, Type, Val);
match_syntax_type(S, Type, {word_or_setting,_,Val}) ->
    match_syntax_type(S, Type, Val);
match_syntax_type(_S, _Type, {Atom,Line})
  when is_atom(Atom), is_integer(Line) ->
    throw(nomatch);
match_syntax_type(S, {fixedtypevaluefield,Name,#type{}=T,_,_}=Type,
		  #'Externalvaluereference'{}=ValRef0) ->
    try get_referenced_type(S, ValRef0) of
	{M,#valuedef{}=ValDef} ->
	    match_syntax_type(update_state(S, M), Type, ValDef)
    catch
	throw:{error,_} ->
	    ValRef = #valuedef{name=Name,
			       type=T,
			       value=ValRef0,
			       module=S#state.mname},
	    match_syntax_type(S, Type, ValRef)
    end;
match_syntax_type(S, {fixedtypevaluefield,Name,#type{},_,_}, #valuedef{}=Val0) ->
    Val = check_value(S, Val0),
    {match,[{Name,Val}]};
match_syntax_type(S, {fixedtypevaluefield,Name,#type{},_,_},
		  {'ValueFromObject',{object,Object},FieldNames}) ->
    Val = extract_field(S, Object, FieldNames),
    {match,[{Name,Val}]};
match_syntax_type(S, {fixedtypevaluefield,Name,#type{}=T,_,_}=Type, Any) ->
    ValDef = #valuedef{name=Name,type=T,value=Any,module=S#state.mname},
    match_syntax_type(S, Type, ValDef);
match_syntax_type(_S, {fixedtypevaluesetfield,Name,#type{},_}, Any) ->
    {match,[{Name,Any}]};
match_syntax_type(S, {objectfield,Name,_,_,_}, #'Externalvaluereference'{}=Ref) ->
    {M,Obj} = get_referenced_type(S, Ref),
    check_object(S, Obj, object_to_check(S, Obj)),
    {match,[{Name,Ref#'Externalvaluereference'{module=M}}]};
match_syntax_type(S, {objectfield,Name,Class,_,_}, {object,_,_}=ObjDef) ->
    InlinedObjName = list_to_atom(lists:concat([S#state.tname,
						'_',Name])),
    ObjSpec = #'Object'{classname=Class,def=ObjDef},
    CheckedObj = check_object(S, #typedef{typespec=ObjSpec}, ObjSpec),
    InlObj = #typedef{checked=true,name=InlinedObjName,typespec=CheckedObj},
    ObjKey = {InlinedObjName, InlinedObjName},
    insert_once(S, inlined_objects, ObjKey),
    %% Which module to use here? Could it be other than top_module?
    asn1_db:dbput(get(top_module), InlinedObjName, InlObj),
    {match,[{Name,InlObj}]};
match_syntax_type(_S, {objectfield,Name,_,_,_}, Any) ->
    {match,[{Name,Any}]};
match_syntax_type(S, {objectsetfield,Name,CDef0,_}, Any) ->
    CDef = case CDef0 of
	       #type{def=CDef1} -> CDef1;
	       CDef1 -> CDef1
	   end,
    case match_syntax_objset(S, Any, CDef) of
	#typedef{typespec=#'ObjectSet'{}=Ts0}=Def ->
	    Ts = check_object(S, Def, Ts0),
	    {match,[{Name,Def#typedef{checked=true,typespec=Ts}}]};
	_ ->
	    syntax_match_error(S, Any)
    end;
match_syntax_type(S, {typefield,Name0,_}, #type{def={pt,_,_}=Def}=Actual) ->
    %% This is an inlined type. If constructed type, save in data base.
    T = check_type(S, #typedef{typespec=Actual}, Actual),
    #'Externaltypereference'{type=PtName} = element(2, Def),
    NameList = [PtName,S#state.tname],
    Name = list_to_atom(asn1ct_gen:list2name(NameList)),
    NewTDef = #typedef{checked=true,name=Name,typespec=T},
    asn1_db:dbput(S#state.mname, Name, NewTDef),
    insert_once(S, parameterized_objects, {Name,type,NewTDef}),
    {match,[{Name0,NewTDef}]};
match_syntax_type(S, {typefield,Name,_}, #type{def=#'ObjectClassFieldType'{}}=Actual) ->
    T = check_type(S, #typedef{typespec=Actual}, Actual),
    {match,[{Name,ocft_def(T)}]};
match_syntax_type(S, {typefield,Name,_}, #type{def=#'Externaltypereference'{}=Ref}) ->
    match_syntax_external(S, Name, Ref);
match_syntax_type(S, {typefield,Name,_}, #type{def=Def}=Actual) ->
    T = check_type(S, #typedef{typespec=Actual}, Actual),
    TypeName = asn1ct_gen:type(asn1ct_gen:get_inner(Def)),
    {match,[{Name,#typedef{checked=true,name=TypeName,typespec=T}}]};
match_syntax_type(S, {typefield,Name,_}, #'Externaltypereference'{}=Ref) ->
    match_syntax_external(S, Name, Ref);
match_syntax_type(_S, {variabletypevaluefield,Name,_,_}, Any) ->
    {match,[{Name,Any}]};
match_syntax_type(_S, {variabletypevaluesetfield,Name,_,_}, Any) ->
    {match,[{Name,Any}]};
match_syntax_type(_S, _Type, _Actual) ->
    throw(nomatch).

match_syntax_params(S0, #ptypedef{name=Name}=PtDef,
		    #'Externaltypereference'{module=M,type=N}=ERef0, Args) ->
    S = S0#state{mname=M,module=load_asn1_module(S0, M),tname=Name},
    Type = check_type(S, PtDef, #type{def={pt,ERef0,Args}}),
    ERefName = new_reference_name(N),
    ERef = #'Externaltypereference'{type=ERefName,module=S0#state.mname},
    TDef = #typedef{checked=true,name=ERefName,typespec=Type},
    insert_once(S0, parameterized_objects, {ERefName,type,TDef}),
    asn1_db:dbput(S0#state.mname, ERef#'Externaltypereference'.type, TDef),
    ERef.

match_syntax_external(#state{mname=Mname}=S0, Name, Ref0) ->
    {M,T0} = get_referenced_type(S0, Ref0),
    Ref1 = Ref0#'Externaltypereference'{module=M},
    case T0 of
	#ptypedef{} ->
	    {params,Name,T0,Ref1};
	#typedef{checked=false}=TDef0 when Mname =/= M  ->
	    %% This typedef is an imported type (or maybe a set.asn
	    %% compilation).
	    S = S0#state{mname=M,module=load_asn1_module(S0, M),
			 tname=get_datastr_name(TDef0)},
	    Type = check_type(S, TDef0, TDef0#typedef.typespec),
	    TDef = TDef0#typedef{checked=true,typespec=Type},
	    asn1_db:dbput(M, get_datastr_name(TDef), TDef),
	    {match,[{Name,merged_name(S, Ref1)}]};
	TDef ->
	    %% This might be a renamed type in a set of specs,
	    %% so rename the ref.
	    Type = asn1ct:get_name_of_def(TDef),
	    Ref = Ref1#'Externaltypereference'{type=Type},
	    {match,[{Name,Ref}]}
    end.

match_syntax_objset(_S, {element_set,_,_}=Set, ClassDef) ->
    make_objset(ClassDef, Set);
match_syntax_objset(S, #'Externaltypereference'{}=Ref, _) ->
    {_,T} = get_referenced_type(S, Ref),
    T;
match_syntax_objset(S, #'Externalvaluereference'{}=Ref, _) ->
    {_,T} = get_referenced_type(S, Ref),
    T;
match_syntax_objset(_, [_|_]=Set, ClassDef) ->
    make_objset(ClassDef, Set);
match_syntax_objset(S, {object,definedsyntax,Words}, ClassDef) ->
    case Words of
	[Word] ->
	    match_syntax_objset_1(S, Word, ClassDef);
	[_|_] ->
	    %% More than one word does not make sense.
	    none
    end;
match_syntax_objset(S, #type{def=#'Externaltypereference'{}=Set}, ClassDef) ->
    match_syntax_objset(S, Set, ClassDef);
match_syntax_objset(_, #type{}, _) ->
    none.

match_syntax_objset_1(S, {setting,_,Set}, ClassDef) ->
    %% Word that starts with an uppercase letter.
    match_syntax_objset(S, Set, ClassDef);
match_syntax_objset_1(S, {word_or_setting,_,Set}, ClassDef) ->
    %% Word in uppercase/hyphens only.
    match_syntax_objset(S, Set, ClassDef);
match_syntax_objset_1(S, #type{def={'TypeFromObject', {object,Object}, FNs}},
		      ClassDef) ->
    Set = extract_field(S, Object, FNs),
    [_|_] = Set,
    #typedef{checked=true,typespec=#'ObjectSet'{class=ClassDef,set=Set}};
match_syntax_objset_1(_, #type{def=#'ObjectClassFieldType'{}}=Set, ClassDef) ->
    make_objset(ClassDef, Set);
match_syntax_objset_1(_, {object,_,_}=Object, ClassDef) ->
    make_objset(ClassDef, [Object]).

make_objset(ClassDef, Set) ->
    #typedef{typespec=#'ObjectSet'{class=ClassDef,set=Set}}.

-spec syntax_match_error(_) -> no_return().
syntax_match_error(S) ->
    asn1_error(S, syntax_nomatch).

-spec syntax_match_error(_, _) -> no_return().
syntax_match_error(S, What0) ->
    What = printable_string(What0),
    asn1_error(S, {syntax_nomatch,What}).

printable_string(Def) ->
    printable_string_1(Def).

printable_string_1({word_or_setting,_,Def}) ->
    printable_string_1(Def);
printable_string_1({value_tag,V}) ->
    printable_string_1(V);
printable_string_1({#seqtag{val=Val1},Val2}) ->
    atom_to_list(Val1) ++ " " ++ printable_string_1(Val2);
printable_string_1(#type{def=Def}) ->
    atom_to_list(asn1ct_gen:get_inner(Def));
printable_string_1(#'Externaltypereference'{type=Type}) ->
    atom_to_list(Type);
printable_string_1(#'Externalvaluereference'{value=Type}) ->
    atom_to_list(Type);
printable_string_1({Atom,Line}) when is_atom(Atom), is_integer(Line) ->
    q(Atom);
printable_string_1({object,definedsyntax,L}) ->
    q(string:join([printable_string_1(Item) || Item <- L], " "));
printable_string_1([_|_]=Def) ->
    case lists:all(fun is_integer/1, Def) of
	true ->
	    lists:flatten(io_lib:format("~p", [Def]));
	false ->
	    q(string:join([printable_string_1(Item) || Item <- Def], " "))
    end;
printable_string_1(Def) ->
    lists:flatten(io_lib:format("~p", [Def])).

q(S) ->
    lists:concat(["\"",S,"\""]).

check_defaultfields(S, Fields, ClassFields) ->
    Present = ordsets:from_list([F || {F,_} <- Fields]),
    Mandatory0 = get_mandatory_class_fields(ClassFields),
    Mandatory = ordsets:from_list(Mandatory0),
    All = ordsets:from_list([element(2, F) || F <- ClassFields]),
    #state{tname=Obj} = S,
    case ordsets:subtract(Present, All) of
	[] ->
	    ok;
	[_|_]=Invalid ->
	    asn1_error(S, {invalid_fields,Invalid,Obj})
    end,
    case ordsets:subtract(Mandatory, Present) of
	[] ->
	    check_defaultfields_1(S, Fields, ClassFields, []);
	[_|_]=Missing ->
	    asn1_error(S, {missing_mandatory_fields,Missing,Obj})
    end.

check_defaultfields_1(_S, [], _ClassFields, Acc) ->
    {object,defaultsyntax,lists:reverse(Acc)};
check_defaultfields_1(S, [{FName,Spec}|Fields], ClassFields, Acc) ->
    CField = lists:keyfind(FName, 2, ClassFields),
    {match,Match} = match_syntax_type(S, CField, Spec),
    check_defaultfields_1(S, Fields, ClassFields, Match++Acc).

get_mandatory_class_fields(ClassFields) ->
    [element(2, F) || F <- ClassFields,
		      is_mandatory_class_field(F)].

is_mandatory_class_field({fixedtypevaluefield,_,_,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field({objectfield,_,_,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field({objectsetfield,_,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field({typefield,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field({variabletypevaluefield,_,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field({variabletypevaluesetfield,_,_,'MANDATORY'}) ->
    true;
is_mandatory_class_field(_) ->
    false.

merged_name(#state{inputmodules=[]},ERef) ->
    ERef;
merged_name(S,ERef=#'Externaltypereference'{module=M}) ->
    case {S#state.mname,lists:member(M,S#state.inputmodules)} of
	{M,_} ->
	    ERef;
	{MergeM,true} -> 
	    %% maybe the reference is renamed
	    NewName = renamed_reference(S,ERef),
	    ERef#'Externaltypereference'{module=MergeM,type=NewName};
	{_,_} -> % i.e. M /= MergeM, not an inputmodule
	    ERef
    end.

ocft_def(#type{def=#'ObjectClassFieldType'{type=OCFT}}=T) ->
    case OCFT of
	{fixedtypevaluefield,_,InnerType} ->
	    case asn1ct_gen:type(asn1ct_gen:get_inner(InnerType#type.def)) of
		Bif when Bif =:= {primitive,bif}; Bif =:= {constructed,bif} ->
		    #typedef{checked=true,name=Bif,typespec=InnerType};
		#'Externaltypereference'{}=Ref ->
		    Ref
	    end;
	'ASN1_OPEN_TYPE' ->
	    #typedef{checked=true,typespec=T#type{def='ASN1_OPEN_TYPE'}}
    end.

check_value(OldS,V) when is_record(V,pvaluesetdef) ->
    #pvaluesetdef{checked=Checked,type=Type} = V,
    case Checked of
	true -> V;
	{error,_} -> V;
	false ->
	    case get_referenced_type(OldS,Type#type.def) of
		{_,Class} when is_record(Class,classdef) ->
		    throw({pobjectsetdef});
		_ -> continue
	    end
    end;
check_value(_OldS,V) when is_record(V,pvaluedef) ->
    %% Fix this case later
    V;
check_value(OldS,V) when is_record(V,typedef) ->
    %% This case when a value set has been parsed as an object set.
    %% It may be a value set
    ?dbg("check_value, V: ~p~n",[V]),
    #typedef{typespec=TS} = V,
    case TS of 
	#'ObjectSet'{class=ClassRef} ->
	    {_RefM,TSDef} = get_referenced_type(OldS, ClassRef),
	    case TSDef of
		#classdef{} -> throw({objectsetdef});
		#typedef{typespec=#type{def=Eref}} when 
		      is_record(Eref,'Externaltypereference') ->
		    %% This case if the class reference is a defined
		    %% reference to class
		    check_value(OldS,V#typedef{typespec=TS#'ObjectSet'{class=Eref}});
		#typedef{typespec=HostType} ->
		    % an ordinary value set with a type in #typedef.typespec
		    ValueSet0 = TS#'ObjectSet'.set,
		    Constr = check_constraints(OldS, HostType, [ValueSet0]),
		    Type = check_type(OldS,TSDef,TSDef#typedef.typespec),
		    {valueset,Type#type{constraint=Constr}}
	    end;
	_ ->
	    throw({objectsetdef})
    end;
check_value(S,#valuedef{pos=Pos,name=Name,type=Type,
			  value={valueset,Constr}}) ->
    NewType = Type#type{constraint=[Constr]},
    {valueset,
     check_type(S,#typedef{pos=Pos,name=Name,typespec=NewType},NewType)};
check_value(S, #valuedef{}=V) ->
    ?dbg("check_value, V: ~p~n",[V0]),
    case V of
	#valuedef{checked=true} ->
	    V;
	#valuedef{checked=false} ->
	    check_valuedef(S, V)
    end.

check_valuedef(#state{recordtopname=TopName}=S0, V0) ->
    #valuedef{name=Name,type=Vtype0,value=Value,module=ModName} = V0,
    V = V0#valuedef{checked=true},
    Vtype = check_type(S0, #typedef{name=Name,typespec=Vtype0},Vtype0),
    Def = Vtype#type.def,
    S1 = S0#state{tname=Def},
    SVal = update_state(S1, ModName),
    case Def of
	#'Externaltypereference'{type=RecName}=Ext ->
	    {RefM,Type} = get_referenced_type(S1, Ext),
	    %% If V isn't a value but an object Type is a #classdef{}
	    S2 = update_state(S1, RefM),
	    case Type of
		#typedef{typespec=TypeSpec0}=TypeDef ->
		    TypeSpec = check_type(S2, TypeDef, TypeSpec0),
		    S3 = case is_contextswitchtype(Type) of
			     true ->
				 S2;
			     false ->
				 S2#state{recordtopname=[RecName|TopName]}
			 end,
		    #valuedef{value=CheckedVal} =
			check_value(S3, V0#valuedef{type=TypeSpec}),
		    V#valuedef{value=CheckedVal};
		#type{} ->
		    %% A parameter that couldn't be categorized.
		    #valuedef{value=CheckedVal} =
			check_value(S2#state{recordtopname=[RecName|TopName]},
				    V#valuedef{type=Type}),
		    V#valuedef{value=CheckedVal}
	    end;
	'ASN1_OPEN_TYPE' ->
	    {opentypefieldvalue,ANYType,ANYValue} = Value,
	    CheckedV = check_value(SVal,#valuedef{name=Name,
						  type=ANYType,
						  value=ANYValue,
						  module=ModName}),
	    V#valuedef{value=CheckedV#valuedef.value};
	'INTEGER' ->
	    V#valuedef{value=normalize_value(SVal, Vtype, Value, [])};
	{'INTEGER',_NamedNumberList} ->
	    V#valuedef{value=normalize_value(SVal, Vtype, Value, [])};
	#'SEQUENCE'{} ->
	    {ok,SeqVal} = convert_external(SVal, Vtype, Value),
	    V#valuedef{value=normalize_value(SVal, Vtype, SeqVal, TopName)};
	_ ->
	    V#valuedef{value=normalize_value(SVal, Vtype, Value, TopName)}
    end.

is_contextswitchtype(#typedef{name='EXTERNAL'})->
    true;
is_contextswitchtype(#typedef{name='EMBEDDED PDV'}) ->
    true;
is_contextswitchtype(#typedef{name='CHARACTER STRING'}) ->
    true;
is_contextswitchtype(_) ->
    false.

%%%
%%% Start of OBJECT IDENTFIER/RELATIVE-OID validation.
%%%

validate_objectidentifier(S, OidType, #'Externalvaluereference'{}=Id) ->
    %% Must be an OBJECT IDENTIFIER or RELATIVE-OID depending on OidType.
    get_oid_value(S, OidType, false, Id);
validate_objectidentifier(S, OidType, {'ValueFromObject',{object,Obj},Fields}) ->
    %% Must be an OBJECT IDENTIFIER/RELATIVE-OID depending on OidType.
    case extract_field(S, Obj, Fields) of
	#valuedef{checked=true,value=Value,type=Type} when is_tuple(Value) ->
	    _ = get_oid_type(S, OidType, Type),
	    Value;
	_ ->
	    asn1_error(S, {illegal_oid,OidType})
    end;
validate_objectidentifier(S, OidType,
			  [{#seqtag{module=Mod,pos=Pos,val=Atom},Val}]) ->
    %% This case is when an OBJECT IDENTIFIER value has been parsed as a
    %% SEQUENCE value.
    Rec = #'Externalvaluereference'{pos=Pos,
				    module=Mod,
				    value=Atom},
    validate_oid(S, OidType, [Rec,Val], []);
validate_objectidentifier(S, OidType, [_|_]=L0) ->
    validate_oid(S, OidType, L0, []);
validate_objectidentifier(S, OidType, _) ->
    asn1_error(S, {illegal_oid,OidType}).

get_oid_value(S, OidType, AllowInteger, #'Externalvaluereference'{}=Id) ->
    case get_referenced_type(S, Id) of
	{_,#valuedef{checked=Checked,type=Type,value=V}} ->
	    case get_oid_type(S, OidType, Type) of
		'INTEGER' when not AllowInteger ->
		    asn1_error(S, {illegal_oid,OidType});
		_ when Checked ->
		    V;
		'INTEGER' ->
		    V;
		_ ->
		    validate_objectidentifier(S, OidType, V)
	    end;
	_ ->
	    asn1_error(S, {illegal_oid,OidType})
    end.

validate_oid(S, OidType, [], Acc) ->
    Oid = lists:reverse(Acc),
    validate_oid_path(S, OidType, Oid),
    list_to_tuple(Oid);
validate_oid(S, OidType, [Value|Vrest], Acc) when is_integer(Value) ->
    validate_oid(S, OidType, Vrest, [Value|Acc]);
validate_oid(S, OidType, [{'NamedNumber',_Name,Value}|Vrest], Acc)
  when is_integer(Value) ->
    validate_oid(S, OidType, Vrest, [Value|Acc]);
validate_oid(S, OidType, [#'Externalvaluereference'{}=Id|Vrest], Acc) ->
    NeededOidType = case Acc of
			[] -> o_id;
			[_|_] -> rel_oid
		    end,
    try get_oid_value(S, NeededOidType, true, Id) of
	Val when is_integer(Val) ->
	    validate_oid(S, OidType, Vrest, [Val|Acc]);
	Val when is_tuple(Val) ->
	    L = tuple_to_list(Val),
	    validate_oid(S, OidType, Vrest, lists:reverse(L, Acc))
    catch
	_:_ ->
	    case reserved_objectid(Id#'Externalvaluereference'.value, Acc) of
		Value when is_integer(Value) ->
		    validate_oid(S, OidType,Vrest, [Value|Acc]);
		false ->
		    asn1_error(S, {illegal_oid,OidType})
	    end
    end;
validate_oid(S, OidType, _V, _Acc) ->
    asn1_error(S, {illegal_oid,OidType}).

get_oid_type(S, OidType, #type{def=Def}) ->
    get_oid_type(S, OidType, Def);
get_oid_type(S, OidType, #'Externaltypereference'{}=Id) ->
    {_,OI} = get_referenced_type(S, Id),
    get_oid_type(S, OidType, OI#typedef.typespec);
get_oid_type(_S, o_id, 'OBJECT IDENTIFIER'=T) ->
    T;
get_oid_type(_S, rel_oid, 'RELATIVE-OID'=T) ->
    T;
get_oid_type(_S, _, 'INTEGER'=T) ->
    T;
get_oid_type(S, OidType, _) ->
    asn1_error(S, {illegal_oid,OidType}).

%% ITU-T Rec. X.680 Annex B - D
reserved_objectid('itu-t',[]) -> 0;
reserved_objectid('ccitt',[]) -> 0;
%% arcs below "itu-t" 
reserved_objectid('recommendation',[0]) -> 0;
reserved_objectid('question',[0]) -> 1;
reserved_objectid('administration',[0]) -> 2;
reserved_objectid('network-operator',[0]) -> 3;
reserved_objectid('identified-organization',[0]) -> 4;
%% arcs below "recommendation"
reserved_objectid('a',[0,0]) -> 1;
reserved_objectid('b',[0,0]) -> 2;
reserved_objectid('c',[0,0]) -> 3;
reserved_objectid('d',[0,0]) -> 4;
reserved_objectid('e',[0,0]) -> 5;
reserved_objectid('f',[0,0]) -> 6;
reserved_objectid('g',[0,0]) -> 7;
reserved_objectid('h',[0,0]) -> 8;
reserved_objectid('i',[0,0]) -> 9;
reserved_objectid('j',[0,0]) -> 10;
reserved_objectid('k',[0,0]) -> 11;
reserved_objectid('l',[0,0]) -> 12;
reserved_objectid('m',[0,0]) -> 13;
reserved_objectid('n',[0,0]) -> 14;
reserved_objectid('o',[0,0]) -> 15;
reserved_objectid('p',[0,0]) -> 16;
reserved_objectid('q',[0,0]) -> 17;
reserved_objectid('r',[0,0]) -> 18;
reserved_objectid('s',[0,0]) -> 19;
reserved_objectid('t',[0,0]) -> 20;
reserved_objectid('u',[0,0]) -> 21;
reserved_objectid('v',[0,0]) -> 22;
reserved_objectid('w',[0,0]) -> 23;
reserved_objectid('x',[0,0]) -> 24;
reserved_objectid('y',[0,0]) -> 25;
reserved_objectid('z',[0,0]) -> 26;

reserved_objectid(iso,[]) -> 1;
%% arcs below "iso", note that number 1 is not used
reserved_objectid('standard',[1]) -> 0;
reserved_objectid('member-body',[1]) -> 2;
reserved_objectid('identified-organization',[1]) -> 3;

reserved_objectid('joint-iso-itu-t',[]) -> 2;
reserved_objectid('joint-iso-ccitt',[]) -> 2;

reserved_objectid(_,_) -> false.

validate_oid_path(_, rel_oid, _) ->
    ok;
validate_oid_path(_, o_id, [0,I|_]) when 0 =< I, I =< 9 ->
    ok;
validate_oid_path(_, o_id, [1,I|_]) when 0 =< I, I =< 3 ->
    ok;
validate_oid_path(_, o_id, [2|_]) ->
    ok;
validate_oid_path(S, o_id=OidType, _) ->
    asn1_error(S, {illegal_oid,OidType}).

%%%
%%% End of OBJECT IDENTFIER/RELATIVE-OID validation.
%%%

convert_external(S, Vtype, Value) ->
    case Vtype of
	#type{tag=[{tag,'UNIVERSAL',8,'IMPLICIT',32}]} ->
	    %% this is an 'EXTERNAL' (or INSTANCE OF)
	    case Value of
		[{#seqtag{val=identification},_}|_] ->
		    {ok,to_EXTERNAL1990(S, Value)};
		_ ->
		    {ok,Value}
	    end;
	_ ->
	    {ok,Value}
    end.

to_EXTERNAL1990(S, [{#seqtag{val=identification}=T,
		     {'CHOICE',{syntax,Stx}}}|Rest]) ->
    to_EXTERNAL1990(S, Rest, [{T#seqtag{val='direct-reference'},Stx}]);
to_EXTERNAL1990(S, [{#seqtag{val=identification}=T,
		     {'CHOICE',{'presentation-context-id',I}}}|Rest]) ->
    to_EXTERNAL1990(S, Rest, [{T#seqtag{val='indirect-reference'},I}]);
to_EXTERNAL1990(S, [{#seqtag{val=identification}=T,
		     {'CHOICE',{'context-negotiation',[{_,PCid},{_,TrStx}]}}}|Rest]) ->
    to_EXTERNAL1990(S, Rest, [{T#seqtag{val='indirect-reference'},PCid},
			      {T#seqtag{val='direct-reference'},TrStx}]);
to_EXTERNAL1990(S, _) ->
    asn1_error(S, illegal_external_value).

to_EXTERNAL1990(S, [V={#seqtag{val='data-value-descriptor'},_}|Rest], Acc) ->
    to_EXTERNAL1990(S, Rest, [V|Acc]);
to_EXTERNAL1990(_S, [{#seqtag{val='data-value'}=T,Val}], Acc) ->
    Encoding = {T#seqtag{val=encoding},{'CHOICE',{'octet-aligned',Val}}},
    lists:reverse([Encoding|Acc]);
to_EXTERNAL1990(S, _, _) ->
    asn1_error(S, illegal_external_value).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Functions to normalize the default values of SEQUENCE 
%% and SET components into Erlang valid format
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
normalize_value(_,_,mandatory,_) ->
    mandatory;
normalize_value(_,_,'OPTIONAL',_) ->
    'OPTIONAL';
normalize_value(S, Type, {'DEFAULT',Value}, NameList) ->
    case catch get_canonic_type(S,Type,NameList) of
	{'BOOLEAN',CType,_} ->
	    normalize_boolean(S,Value,CType);
	{'INTEGER',CType,_} ->
	    normalize_integer(S, Value, CType);
	{'BIT STRING',CType,_} ->
	    normalize_bitstring(S,Value,CType);
	{'OCTET STRING',_,_} ->
	    normalize_octetstring(S, Value);
	{'NULL',_CType,_} ->
	    %%normalize_null(Value);
	    'NULL';
	{'RELATIVE-OID',_,_} ->
	    normalize_relative_oid(S,Value);
	{'OBJECT IDENTIFIER',_,_} ->
	    normalize_objectidentifier(S,Value);
	{'ObjectDescriptor',_,_} ->
	    normalize_objectdescriptor(Value);
	{'REAL',_,_} ->
	    normalize_real(Value);
	{'ENUMERATED',CType,_} ->
	    normalize_enumerated(S,Value,CType);
	{'CHOICE',CType,NewNameList} ->
	    normalize_choice(S,Value,CType,NewNameList);
	{'SEQUENCE',CType,NewNameList} ->
	    normalize_sequence(S,Value,CType,NewNameList);
	{'SEQUENCE OF',CType,NewNameList} ->
	    normalize_seqof(S,Value,CType,NewNameList);
	{'SET',CType,NewNameList} ->
	    normalize_set(S,Value,CType,NewNameList);
	{'SET OF',CType,NewNameList} ->
	    normalize_setof(S,Value,CType,NewNameList);
	{restrictedstring,CType,_} ->
	    normalize_restrictedstring(S,Value,CType);
	{'ASN1_OPEN_TYPE',{typefield,_TF},NL} -> %an open type
	    normalize_objectclassfieldvalue(S,Value,NL);
	Err ->
	    asn1ct:warning("could not check default value ~p~nType:~n~p~nNameList:~n~p~n",
			   [Value,Type,Err],S,"could not check default value"),
	    Value
    end;
normalize_value(S,Type,Val,NameList) ->
    normalize_value(S,Type,{'DEFAULT',Val},NameList).

normalize_boolean(_,true,_) ->
    true;
normalize_boolean(_,false,_) ->
    false;
normalize_boolean(S,Bool=#'Externalvaluereference'{},CType) ->
    get_normalized_value(S,Bool,CType,fun normalize_boolean/3,[]);
normalize_boolean(S, _, _) ->
    asn1_error(S, {illegal_value, "BOOLEAN"}).

normalize_integer(_S, Int, _) when is_integer(Int) ->
    Int;
normalize_integer(S, #'Externalvaluereference'{value=Name}=Ref, NNL) ->
    case lists:keyfind(Name, 1, NNL) of
	{Name,Val} ->
	    Val;
	false ->
	    try get_referenced_value(S, Ref) of
		Val when is_integer(Val) ->
		    Val;
		_ ->
		    asn1_error(S, illegal_integer_value)
	    catch
		throw:_ ->
		    asn1_error(S, illegal_integer_value)
	    end
    end;
normalize_integer(S, {'ValueFromObject',{object,Obj},FieldNames}, _) ->
    case extract_field(S, Obj, FieldNames) of
	#valuedef{value=Val} when is_integer(Val) ->
	    Val;
	_ ->
	    asn1_error(S, illegal_integer_value)
    end;
normalize_integer(S, _, _) ->
    asn1_error(S, illegal_integer_value).

%% normalize_bitstring(S, Value, Type) -> bitstring()
%%  Convert a literal value for a BIT STRING to an Erlang bit string.
%%
normalize_bitstring(S, Value, Type)->
    case Value of
	{hstring,String} when is_list(String) ->
	    hstring_to_bitstring(String);
	{bstring,String} when is_list(String) ->
	    bstring_to_bitstring(String);
	#'Externalvaluereference'{} ->
	    Val = get_referenced_value(S, Value),
	    normalize_bitstring(S, Val, Type);
	{'ValueFromObject',{object,Obj},FieldNames} ->
	    case extract_field(S, Obj, FieldNames) of
		#valuedef{value=Val} ->
		    normalize_bitstring(S, Val, Type);
		_ ->
		    asn1_error(S, {illegal_value, "BIT STRING"})
	    end;
	RecList when is_list(RecList) ->
	    [normalize_bs_item(S, Item, Type) || Item <- RecList];
	Bs when is_bitstring(Bs) ->
	    %% Already normalized.
	    Bs;
	_ ->
	    asn1_error(S, {illegal_value, "BIT STRING"})
    end.

normalize_bs_item(S, #'Externalvaluereference'{value=Name}, Type) ->
    case lists:keymember(Name, 1, Type) of
	true -> Name;
	false -> asn1_error(S, {illegal_value, "BIT STRING"})
    end;
normalize_bs_item(_, Atom, _) when is_atom(Atom) ->
    Atom;
normalize_bs_item(S, _, _) ->
    asn1_error(S, {illegal_value, "BIT STRING"}).

hstring_to_binary(L) ->
    byte_align(hstring_to_bitstring(L)).

bstring_to_binary(L) ->
    byte_align(bstring_to_bitstring(L)).

byte_align(Bs) ->
    case bit_size(Bs) rem 8 of
	0 -> Bs;
	N -> <<Bs/bitstring,0:(8-N)>>
    end.

hstring_to_bitstring(L) ->
    << <<(hex_to_int(D)):4>> || D <- L >>.

bstring_to_bitstring(L) ->
    << <<(D-$0):1>> || D <- L >>.

hex_to_int(D) when $0 =< D, D =< $9 -> D - $0;
hex_to_int(D) when $A =< D, D =< $F -> D - ($A - 10).

%% normalize_octetstring/1 changes representation of input Value to a 
%% list of octets.
%% Format of Value is one of:
%% {bstring,String} each element in String corresponds to one bit in an octet
%% {hstring,String} each element in String corresponds to one byte in an octet
%% #'Externalvaluereference'
normalize_octetstring(S, Value) ->
    case Value of
	{bstring,String} ->
	    bstring_to_binary(String);
	{hstring,String} ->
	    hstring_to_binary(String);
	#'Externalvaluereference'{} ->
	    case get_referenced_value(S, Value) of
		String when is_binary(String) ->
		    String;
		Other ->
		    normalize_octetstring(S, Other)
	    end;
	{'ValueFromObject',{object,Obj},FieldNames} ->
	    case extract_field(S, Obj, FieldNames) of
		#valuedef{value=Val} when is_binary(Val) ->
		    Val;
		_ ->
		    asn1_error(S, illegal_octet_string_value)
	    end;
	_ ->
	    asn1_error(S, illegal_octet_string_value)
    end.

normalize_objectidentifier(S, Value) ->
    validate_objectidentifier(S, o_id, Value).

normalize_relative_oid(S, Value) ->
    validate_objectidentifier(S, rel_oid, Value).

normalize_objectdescriptor(Value) ->
    Value.

normalize_real(Value) ->
    Value.

normalize_enumerated(S, Id0, NNL) ->
    {Id,_} = lookup_enum_value(S, Id0, NNL),
    Id.

lookup_enum_value(S, Id, {Base,Ext}) ->
    %% Extensible ENUMERATED.
    lookup_enum_value(S, Id, Base++Ext);
lookup_enum_value(S, #'Externalvaluereference'{value=Id}, NNL) ->
    lookup_enum_value(S, Id, NNL);
lookup_enum_value(S, Id, NNL) when is_atom(Id) ->
    case lists:keyfind(Id, 1, NNL) of
	{_,_}=Ret ->
	    Ret;
	false ->
	    asn1_error(S, {undefined,Id})
    end.

normalize_choice(S, {'CHOICE',{C,V}}, CType, NameList)
  when is_atom(C) ->
    case lists:keyfind(C, #'ComponentType'.name, CType) of
	#'ComponentType'{typespec=CT,name=Name} ->
	    {C,normalize_value(S, CT, {'DEFAULT',V}, [Name|NameList])};
	false ->
	    asn1_error(S, {illegal_id,C})
    end;
normalize_choice(S,CV={Name,_ChoiceVal},CType,NameList)
  when is_atom(Name) ->
    normalize_choice(S,{'CHOICE',CV},CType,NameList);
normalize_choice(S, V, _CType, _NameList) ->
    asn1_error(S, {illegal_id, error_value(V)}).

normalize_sequence(S,Value,Components,NameList) 
  when is_tuple(Components) ->
    normalize_sequence(S,Value,lists:flatten(tuple_to_list(Components)),
		       NameList); 
normalize_sequence(S,{Name,Value},Components,NameList) 
  when is_atom(Name),is_list(Value) ->
    normalize_sequence(S,Value,Components,NameList);
normalize_sequence(S,Value,Components,NameList) ->
    normalized_record('SEQUENCE',S,Value,Components,NameList).

normalize_set(S,Value,Components,NameList) when is_tuple(Components) ->
    normalize_set(S,Value,lists:flatten(tuple_to_list(Components)),NameList);
normalize_set(S,{Name,Value},Components,NameList) 
  when is_atom(Name),is_list(Value) ->
    normalized_record('SET',S,Value,Components,NameList);
normalize_set(S,Value,Components,NameList) ->
    NewName = list_to_atom(asn1ct_gen:list2name(NameList)),
    case is_record_normalized(S,NewName,Value,length(Components)) of
	true ->
	    Value;
	_ ->
	    SortedVal = sort_value(Components,Value),
	    normalized_record('SET',S,SortedVal,Components,NameList)
    end.

sort_value(Components, Value0) when is_list(Value0) ->
    {Keys0,_} = lists:mapfoldl(fun(#'ComponentType'{name=N}, I) ->
				       {{N,I},I+1}
			       end, 0, Components),
    Keys = gb_trees:from_orddict(orddict:from_list(Keys0)),
    Value1 = [{case gb_trees:lookup(N, Keys) of
		   {value,K} -> K;
		   none -> 'end'
	       end,Pair} || {#seqtag{val=N},_}=Pair <- Value0],
    Value = lists:sort(Value1),
    [Pair || {_,Pair} <- Value];
sort_value(_Components, #'Externalvaluereference'{}=Value) ->
    %% Sort later.
    Value.

sort_val_if_set(['SET'|_],Val,Type) ->
    sort_value(Type,Val);
sort_val_if_set(_,Val,_) ->
    Val.

normalized_record(SorS,S,Value,Components,NameList) ->
    NewName = list_to_atom(lists:concat([get_record_prefix_name(S),
					 asn1ct_gen:list2name(NameList)])),
    case is_record_normalized(S,NewName,Value,length(Components)) of
	true ->
	    Value;
	false ->
	    NoComps = length(Components),
	    ListOfVals = normalize_seq_or_set(SorS,S,Value,Components,NameList,[]),
	    NoComps = length(ListOfVals),       %Assertion.
            case use_maps(S) of
                false ->
                    list_to_tuple([NewName|ListOfVals]);
                true ->
                    create_map_value(Components, ListOfVals)
            end
    end.

is_record_normalized(S,Name,V = #'Externalvaluereference'{},NumComps) ->
    case get_referenced_type(S,V) of
	{_M,#valuedef{type=_T1,value=V2}} ->
	    is_record_normalized(S,Name,V2,NumComps);
	_ -> false
    end;
is_record_normalized(_S,Name,Value,NumComps) when is_tuple(Value) ->
    (tuple_size(Value) =:= (NumComps + 1)) andalso (element(1, Value) =:= Name);
is_record_normalized(_S, _Name, Value, _NumComps) when is_map(Value) ->
    true;
is_record_normalized(_,_,_,_) ->
    false.

use_maps(#state{options=Opts}) ->
    lists:member(maps, Opts).

create_map_value(Components, ListOfVals) ->
    Zipped = lists:zip(Components, ListOfVals),
    L = [{Name,V} || {#'ComponentType'{name=Name},V} <- Zipped,
                     V =/= asn1_NOVALUE],
    maps:from_list(L).

normalize_seq_or_set(SorS, S,
		     [{#seqtag{val=Cname},V}|Vs],
		     [#'ComponentType'{name=Cname,typespec=TS}|Cs],
		     NameList, Acc) ->
    NewNameList =
	case TS#type.def of
	    #'Externaltypereference'{type=TName} ->
		[TName];
	    _ -> [Cname|NameList]
	end,
    NVal = normalize_value(S,TS,{'DEFAULT',V},NewNameList),
    normalize_seq_or_set(SorS,S,Vs,Cs,NameList,[NVal|Acc]);
normalize_seq_or_set(SorS, S,
		     Values=[{#seqtag{val=Cname0},_V}|_Vs],
		     [#'ComponentType'{prop='OPTIONAL'}|Cs],
		     NameList, Acc) ->
    verify_valid_component(S, Cname0, Cs),
    normalize_seq_or_set(SorS,S,Values,Cs,NameList,[asn1_NOVALUE|Acc]);
normalize_seq_or_set(SorS, S,
		     Values=[{#seqtag{val=Cname0},_V}|_Vs],
		     [#'ComponentType'{name=Cname,typespec=TS,
				       prop={'DEFAULT',Value}}|Cs],
		    NameList, Acc) ->
    verify_valid_component(S, Cname0, Cs),
    NewNameList =
	case TS#type.def of
	    #'Externaltypereference'{type=TName} ->
		[TName];
	    _ -> [Cname|NameList]
	end,
    NVal =  normalize_value(S,TS,{'DEFAULT',Value},NewNameList),
    normalize_seq_or_set(SorS,S,Values,Cs,NameList,[NVal|Acc]);
%% If default value is {} ComponentTypes in SEQUENCE are marked DEFAULT 
%% or OPTIONAL (or the type is defined SEQUENCE{}, which is handled by
%% the previous case).
normalize_seq_or_set(SorS,S,[],
		     [#'ComponentType'{name=Name,typespec=TS,
				       prop={'DEFAULT',Value}}|Cs],
		     NameList,Acc) ->
    NewNameList =
	case TS#type.def of
	    #'Externaltypereference'{type=TName} ->
		[TName];
	    _ -> [Name|NameList]
	end,
    NVal =  normalize_value(S,TS,{'DEFAULT',Value},NewNameList),
    normalize_seq_or_set(SorS,S,[],Cs,NameList,[NVal|Acc]);
normalize_seq_or_set(SorS,S,[],[#'ComponentType'{prop='OPTIONAL'}|Cs],
		     NameList,Acc) ->
    normalize_seq_or_set(SorS,S,[],Cs,NameList,[asn1_NOVALUE|Acc]);
normalize_seq_or_set(SorS,S,Value=#'Externalvaluereference'{},
		     Cs,NameList,Acc) ->
    get_normalized_value(S,Value,Cs,fun normalize_seq_or_set/6,
			 [SorS,NameList,Acc]);
normalize_seq_or_set(_SorS, _S, [], [], _, Acc) ->
    lists:reverse(Acc);
normalize_seq_or_set(_SorS, S, V, Cs, _, _) ->
    case V of
	[{#seqtag{val=Name},_}|_] ->
	    asn1_error(S, {illegal_id,error_value(Name)});
	[] ->
	    [#'ComponentType'{name=Name}|_] = Cs,
	    asn1_error(S, {missing_id,error_value(Name)})
    end.

verify_valid_component(S, Name, Cs) ->
    case lists:keyfind(Name, #'ComponentType'.name, Cs) of
	false -> asn1_error(S, {illegal_id,error_value(Name)});
	#'ComponentType'{} -> ok
    end.

normalize_seqof(S,Value,Type,NameList) ->
    normalize_s_of('SEQUENCE OF',S,Value,Type,NameList).

normalize_setof(S,Value,Type,NameList) ->
    normalize_s_of('SET OF',S,Value,Type,NameList).

normalize_s_of(SorS,S,Value,Type,NameList) when is_list(Value) ->
    DefValueList = lists:map(fun(X) -> {'DEFAULT',X} end,Value),
    Suffix = asn1ct_gen:constructed_suffix(SorS,Type),
    Def = Type#type.def,
    InnerType = asn1ct_gen:get_inner(Def),
    WhatKind = asn1ct_gen:type(InnerType),
    NewNameList =
	case WhatKind of
	    {constructed,bif} ->
		[Suffix|NameList];
	    #'Externaltypereference'{type=Name} ->
		[Name];
	    _ -> []
	end,
    NormFun = 	fun (X) -> normalize_value(S,Type,X,
					   NewNameList) end,
    case catch lists:map(NormFun, DefValueList) of
	List when is_list(List) ->
	    List;
	_ ->
	    asn1ct:warning("~p could not handle value ~p~n",[SorS,Value],S,
			   "could not handle value"),
	    Value
    end;
normalize_s_of(SorS,S,Value,Type,NameList) 
  when is_record(Value,'Externalvaluereference') ->
    get_normalized_value(S,Value,Type,fun normalize_s_of/5,
			 [SorS,NameList]).


%% normalize_restrictedstring handles all format of restricted strings.
%% tuple case
% normalize_restrictedstring(_S,[Int1,Int2],_) when is_integer(Int1),is_integer(Int2) ->
%     {Int1,Int2};
% %% quadruple case
% normalize_restrictedstring(_S,[Int1,Int2,Int3,Int4],_) when is_integer(Int1),
% 							   is_integer(Int2),
% 							   is_integer(Int3),
% 							   is_integer(Int4) ->
%     {Int1,Int2,Int3,Int4};
%% character string list case
normalize_restrictedstring(S,[H|T],CType) when is_list(H);is_tuple(H) ->
    [normalize_restrictedstring(S,H,CType)|normalize_restrictedstring(S,T,CType)];
%% character sting case
normalize_restrictedstring(_S,CString,_) when is_list(CString) ->
    CString;
%% definedvalue case or argument in a parameterized type
normalize_restrictedstring(S,ERef,CType) when is_record(ERef,'Externalvaluereference') ->
    get_normalized_value(S,ERef,CType,
			 fun normalize_restrictedstring/3,[]).

normalize_objectclassfieldvalue(S,{opentypefieldvalue,Type,Value},NameList) ->
    %% An open type has per definition no type. Thus should the type
    %% information of the default type be available at
    %% encode/decode. But as encoding the default value causes special
    %% treatment (no encoding) whatever type is used the type
    %% information is not necessary in encode/decode.
    normalize_value(S,Type,Value,NameList);
normalize_objectclassfieldvalue(_S,Other,_NameList) ->
    %% If the type info was thrown away in an earlier step the value
    %% is already normalized.
     Other.

get_normalized_value(S,Val,Type,Func,AddArg) ->
    case catch get_referenced_type(S,Val) of
	{ExtM,_VDef = #valuedef{type=_T1,value=V}} -> 
	    %% should check that Type and T equals
 	    V2 = sort_val_if_set(AddArg,V,Type),
	    call_Func(update_state(S,ExtM),V2,Type,Func,AddArg);
	{error,_} ->
	    asn1ct:warning("default value not comparable ~p~n",[Val],S),
	    Val;
	{ExtM,NewVal} ->
	    V2 = sort_val_if_set(AddArg,NewVal,Type),
	    call_Func(update_state(S,ExtM),V2,Type,Func,AddArg);
	_ ->
	    asn1ct:warning("default value not comparable ~p~n",[Val],S,
			   "default value not comparable"),
	    Val
    end.

call_Func(S,Val,Type,Func,ArgList) ->	    
    case ArgList of
	[] ->
	    Func(S,Val,Type);
	[LastArg] ->
	    Func(S,Val,Type,LastArg);
	[Arg1,LastArg1] ->
	    Func(Arg1,S,Val,Type,LastArg1);
	[Arg1,LastArg1,LastArg2] ->
	    Func(Arg1,S,Val,Type,LastArg1,LastArg2)
    end.

    
get_canonic_type(S,Type,NameList) ->
    {InnerType,NewType,NewNameList} =
	case Type#type.def of
	    'INTEGER'=Name ->
		{Name,[],NameList};
	    Name when is_atom(Name) ->
		{Name,Type,NameList};
	    Ref when is_record(Ref,'Externaltypereference') ->
		{_,#typedef{name=Name,typespec=RefedType}} =
		    get_referenced_type(S,Ref),
		get_canonic_type(S,RefedType,[Name]);
	    {Name,T} when is_atom(Name) -> 
		{Name,T,NameList};
	    Seq when is_record(Seq,'SEQUENCE') -> 
		{'SEQUENCE',Seq#'SEQUENCE'.components,NameList};
	    Set when is_record(Set,'SET') -> 
		{'SET',Set#'SET'.components,NameList};
	    #'ObjectClassFieldType'{type=T} ->
		{'ASN1_OPEN_TYPE',T,NameList}
	end,
    {asn1ct_gen:unify_if_string(InnerType),NewType,NewNameList}.



check_ptype(S,Type,Ts) when is_record(Ts,type) ->
    check_formal_parameters(S, Type#ptypedef.args),
    Def = Ts#type.def,
    NewDef= 
	case Def of 
	    Seq when is_record(Seq,'SEQUENCE') ->
		Components = expand_components(S,Seq#'SEQUENCE'.components),
		#newt{type=Seq#'SEQUENCE'{pname=get_datastr_name(Type),
					  components = Components}};
	    Set when is_record(Set,'SET') ->
		Components = expand_components(S,Set#'SET'.components),
		#newt{type=Set#'SET'{pname=get_datastr_name(Type),
				     components = Components}};
	    _Other ->
		#newt{}
	end,
    Ts2 = case NewDef of
	      #newt{type=unchanged} ->
		  Ts;
	      #newt{type=TDef}->
		  Ts#type{def=TDef}
	  end,
    Ts2;
%parameterized class
check_ptype(_S,_PTDef,Ts) when is_record(Ts,objectclass) ->
    throw({asn1_param_class,Ts}).

check_formal_parameters(S, Args) ->
    _ = [check_formal_parameter(S, A) || A <- Args],
    ok.

check_formal_parameter(_, {_,_}) ->
    ok;
check_formal_parameter(_, #'Externaltypereference'{}) ->
    ok;
check_formal_parameter(S, #'Externalvaluereference'{value=Name}) ->
    asn1_error(S, {illegal_typereference,Name}).

% check_type(S,Type,ObjSpec={{objectclassname,_},_}) ->
 %     check_class(S,ObjSpec);
check_type(_S,Type,Ts) when is_record(Type,typedef),
			   (Type#typedef.checked==true) ->
    Ts;
check_type(_S,Type,Ts) when is_record(Type,typedef),
			   (Type#typedef.checked==idle) -> % the check is going on
    Ts;
check_type(S=#state{recordtopname=TopName},Type,Ts) when is_record(Ts,type) ->
    {Def,Tag,Constr,IsInlined} = 
	case match_parameter(S, Ts#type.def) of
	    #type{tag=PTag,constraint=_Ctmp,def=Dtmp,inlined=Inl} ->
		{Dtmp,merge_tags(Ts#type.tag,PTag),Ts#type.constraint,Inl};
	    #typedef{typespec=#type{tag=PTag,def=Dtmp,inlined=Inl}} ->
		{Dtmp,merge_tags(Ts#type.tag,PTag),Ts#type.constraint,Inl};
	    Dtmp ->
		{Dtmp,Ts#type.tag,Ts#type.constraint,Ts#type.inlined}
	end,
    TempNewDef = #newt{type=Def,tag=Tag,constraint=Constr,
		       inlined=IsInlined},
    TestFun = 
	fun(Tref) ->
		{_, MaybeChoice} = get_referenced_type(S, Tref, true),
		case catch((MaybeChoice#typedef.typespec)#type.def) of
		    {'CHOICE',_} ->
			maybe_illicit_implicit_tag(S, choice, Tag);
		    'ANY' ->
			maybe_illicit_implicit_tag(S, open_type, Tag);
		    'ANY DEFINED BY' ->
			maybe_illicit_implicit_tag(S, open_type, Tag);
		    'ASN1_OPEN_TYPE' ->
			maybe_illicit_implicit_tag(S, open_type, Tag);
		    _ ->
			Tag
		end
	end,
    NewDef= 
	case Def of 
	    Ext when is_record(Ext,'Externaltypereference') ->
		{RefMod,RefTypeDef,IsParamDef} = 
		    case get_referenced_type(S, Ext) of
			{undefined,TmpTDef} -> %% A parameter
			    {get(top_module),TmpTDef,true};
			{TmpRefMod,TmpRefDef} ->
			    {TmpRefMod,TmpRefDef,false}
		    end,
		case get_class_def(S, RefTypeDef) of
		    none -> ok;
		    #classdef{} -> throw({asn1_class,RefTypeDef})
		end,
		Ct = TestFun(Ext),
		{RefType,ExtRef} = 
		    case RefTypeDef#typedef.checked of
			true ->
			    {RefTypeDef#typedef.typespec,Ext};
			_ ->  
			    %% Put as idle to prevent recursive loops
			    NewRefTypeDef1 = RefTypeDef#typedef{checked=idle},
			    asn1_db:dbput(RefMod,
					  get_datastr_name(NewRefTypeDef1),
					  NewRefTypeDef1), 
			    NewS = S#state{mname=RefMod,
					   module=load_asn1_module(S,RefMod),
					   tname=get_datastr_name(NewRefTypeDef1),
					   abscomppath=[],recordtopname=[]},
			    RefType1 = 
				check_type(NewS,RefTypeDef,RefTypeDef#typedef.typespec),
			    %% update the type and mark as checked
			    NewRefTypeDef2 = 
				RefTypeDef#typedef{checked=true,typespec = RefType1},
			    TmpName = get_datastr_name(NewRefTypeDef2),
			    asn1_db:dbput(RefMod,
					  TmpName,
					  NewRefTypeDef2),
			    case {RefMod == get(top_module),IsParamDef} of
				{true,true} ->
				    Key = {TmpName,
					   type,
					   NewRefTypeDef2},
				    asn1ct_gen:insert_once(parameterized_objects,
							   Key);
				_ -> ok
			    end,
			    Pos = Ext#'Externaltypereference'.pos,
			    {RefType1,#'Externaltypereference'{module=RefMod,
							       pos=Pos,
							       type=TmpName}}
		    end,

		case asn1ct_gen:prim_bif(asn1ct_gen:get_inner(RefType#type.def)) of
		    true ->
			%% Here we expand to a built in type and inline it
			NewC = check_constraints(S, RefType, Constr ++
						     RefType#type.constraint),
			TempNewDef#newt{
			  type = RefType#type.def, 
			  tag = merge_tags(Ct,RefType#type.tag),
			  constraint = NewC};
		    _ ->
			%% Here we only expand the tags and keep the ext ref.
			    
			NewExt = ExtRef#'Externaltypereference'{module=merged_mod(S,RefMod,Ext)},
			TempNewDef#newt{
			  type = check_externaltypereference(S,NewExt),
			  tag = merge_tags(Ct,RefType#type.tag)}
		end;
	    'ANY' ->
		Ct = maybe_illicit_implicit_tag(S, open_type, Tag),
		TempNewDef#newt{type='ASN1_OPEN_TYPE',tag=Ct};
	    {'ANY_DEFINED_BY',_} ->
		Ct = maybe_illicit_implicit_tag(S, open_type, Tag),
		TempNewDef#newt{type='ASN1_OPEN_TYPE',tag=Ct};
	    'INTEGER' ->
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_INTEGER))};

	    {'INTEGER',NamedNumberList} ->
		TempNewDef#newt{type={'INTEGER',check_integer(S,NamedNumberList)},
				tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_INTEGER))};
	    'REAL' ->
		check_real(S,Constr),

		TempNewDef#newt{tag=merge_tags(Tag,?TAG_PRIMITIVE(?N_REAL))};
	    {'BIT STRING',NamedNumberList} ->
		NewL = check_bitstring(S, NamedNumberList),
		TempNewDef#newt{type={'BIT STRING',NewL},
				tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_BIT_STRING))};
	    'NULL' ->
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_NULL))};
	    'OBJECT IDENTIFIER' ->
		check_objectidentifier(S,Constr),
		TempNewDef#newt{tag=
			       merge_tags(Tag,?TAG_PRIMITIVE(?N_OBJECT_IDENTIFIER))};
	    'ObjectDescriptor' ->
		TempNewDef#newt{tag=
			       merge_tags(Tag,?TAG_PRIMITIVE(?N_OBJECT_DESCRIPTOR))};
	    'EXTERNAL' ->
		put_once(external,unchecked),
		TempNewDef#newt{type=
				#'Externaltypereference'{module=S#state.mname,
							 type='EXTERNAL'},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_EXTERNAL))};
	    {'INSTANCE OF',DefinedObjectClass,Constraint} ->
		%% check that DefinedObjectClass is of TYPE-IDENTIFIER class
		%% If Constraint is empty make it the general INSTANCE OF type
		%% If Constraint is not empty make an inlined type
		%% convert INSTANCE OF to the associated type
		IOFDef=check_instance_of(S,DefinedObjectClass,Constraint),
		TempNewDef#newt{type=IOFDef,
				tag=merge_tags(Tag,?TAG_CONSTRUCTED(?N_INSTANCE_OF))};
	    {'ENUMERATED',NamedNumberList} ->
		TempNewDef#newt{type=
				{'ENUMERATED',
				 check_enumerated(S, NamedNumberList)},
				tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_ENUMERATED)),
				constraint=[]};
	    'EMBEDDED PDV' ->
		put_once(embedded_pdv,unchecked),
		TempNewDef#newt{type=
				#'Externaltypereference'{module=S#state.mname,
							 type='EMBEDDED PDV'},
				tag= 
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_EMBEDDED_PDV))};
	    'BOOLEAN'->
		check_boolean(S,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_BOOLEAN))};
	    'OCTET STRING' ->
		check_octetstring(S,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_OCTET_STRING))};
	    'NumericString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_NumericString))};
	    TString when TString =:= 'TeletexString'; 
			 TString =:= 'T61String' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_TeletexString))};
	    'VideotexString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_VideotexString))};
	    'UTCTime' ->
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_UTCTime))};
	    'GeneralizedTime' ->
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_GeneralizedTime))};
	    'GraphicString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_GraphicString))};
	    'VisibleString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_VisibleString))};
	    'GeneralString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_GeneralString))};
	    'PrintableString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_PrintableString))};
	    'IA5String' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_IA5String))};
	    'BMPString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_BMPString))};
	    'UniversalString' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_UniversalString))};
	    'UTF8String' ->
		check_restrictedstring(S,Def,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?N_UTF8String))};
	    'RELATIVE-OID' ->
		check_relative_oid(S,Constr),
		TempNewDef#newt{tag=
				merge_tags(Tag,?TAG_PRIMITIVE(?'N_RELATIVE-OID'))};
	    'CHARACTER STRING' ->
		put_once(character_string,unchecked),
		TempNewDef#newt{type=
				#'Externaltypereference'{module=S#state.mname,
							 type='CHARACTER STRING'},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_CHARACTER_STRING))};
	    Seq when is_record(Seq,'SEQUENCE') ->
		RecordName = 
		    case TopName of
			[] ->
			    [get_datastr_name(Type)];
%			    [Type#typedef.name];
			_ -> 
			    TopName
		    end,
		{TableCInf,Components} =
		    check_sequence(S#state{recordtopname=
					   RecordName},
					   Type,Seq#'SEQUENCE'.components),
		TempNewDef#newt{type=Seq#'SEQUENCE'{tablecinf=tablecinf_choose(Seq,TableCInf),
					  components=Components},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_SEQUENCE))};
	    {'SEQUENCE OF',Components} ->
		TempNewDef#newt{type={'SEQUENCE OF',check_sequenceof(S,Type,Components)},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_SEQUENCE))};
	    {'CHOICE',Components} ->
		Ct = maybe_illicit_implicit_tag(S, choice, Tag),
		TempNewDef#newt{type={'CHOICE',check_choice(S,Type,Components)},tag=Ct};
	    Set when is_record(Set,'SET') ->
		RecordName=
		    case TopName of
			[] ->
			    [get_datastr_name(Type)];
%			    [Type#typedef.name];
			_ -> 
			    TopName
		    end,
		{Sorted,TableCInf,Components} =
		    check_set(S#state{recordtopname=RecordName},
			      Type,Set#'SET'.components),
		TempNewDef#newt{type=Set#'SET'{sorted=Sorted,
				     tablecinf=tablecinf_choose(Set,TableCInf),
				     components=Components},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_SET))};
	    {'SET OF',Components} ->
		TempNewDef#newt{type={'SET OF',check_setof(S,Type,Components)},
				tag=
				merge_tags(Tag,?TAG_CONSTRUCTED(?N_SET))};

	    {pt,Ptype,ParaList} ->
		%% Ptype might be a parameterized - type, object set or
		%% value set. If it isn't a parameterized type notify the
		%% calling function.
		{_RefMod,Ptypedef} = get_referenced_type(S,Ptype),
		notify_if_not_ptype(S,Ptypedef),
		NewParaList = match_parameters(S, ParaList),
		Instance = instantiate_ptype(S,Ptypedef,NewParaList),
		TempNewDef#newt{type=Instance#type.def,
				tag=merge_tags(Tag,Instance#type.tag),
				constraint=Instance#type.constraint,
				inlined=yes};

	    #'ObjectClassFieldType'{classname=ClRef0}=OCFT0 ->
		%% this case occures in a SEQUENCE when 
		%% the type of the component is a ObjectClassFieldType
		ClRef = match_parameter(S, ClRef0),
		OCFT = OCFT0#'ObjectClassFieldType'{classname=ClRef},
		ClassSpec = check_class(S,ClRef),
		NewTypeDef = 
		    maybe_open_type(S,ClassSpec,
				    OCFT#'ObjectClassFieldType'{class=ClassSpec},Constr),
		InnerTag = get_innertag(S,NewTypeDef),
		MergedTag = merge_tags(Tag,InnerTag),
		Ct =
		    case is_open_type(NewTypeDef) of
			true ->
			    maybe_illicit_implicit_tag(S, open_type, MergedTag);
			_ ->
			    MergedTag
		    end,
		case TopName of
		    [] when Type#typedef.name =/= undefined ->
			%% This is a top-level type.
			#type{constraint=C,def=Simplified} =
			    simplify_type(#type{def=NewTypeDef,
						constraint=Constr}),
			TempNewDef#newt{type=Simplified,tag=Ct,
					constraint=C};
		    _ ->
			TempNewDef#newt{type=NewTypeDef,tag=Ct}
		end;

	    {'TypeFromObject',{object,Object},TypeField} ->
		CheckedT = get_type_from_object(S,Object,TypeField),
		TempNewDef#newt{tag=merge_tags(Tag,CheckedT#type.tag),
				type=CheckedT#type.def};

	    {'SelectionType',Name,T} ->
		CheckedT = check_selectiontype(S,Name,T),
		TempNewDef#newt{tag=merge_tags(Tag,CheckedT#type.tag),
				type=CheckedT#type.def};
	    'ASN1_OPEN_TYPE' ->
		TempNewDef
	end,
    #newt{type=TDef,tag=NewTags,constraint=NewConstr,inlined=Inlined} = NewDef,
    Ts#type{def=TDef,
	    inlined=Inlined,
	    constraint=check_constraints(S, #type{def=TDef}, NewConstr),
	    tag=lists:map(fun(#tag{type={default,TTx}}=TempTag) ->
				  TempTag#tag{type=TTx};
			     (Other) -> Other
			  end, NewTags)}.


%%
%% Simplify the backends by getting rid of an #'ObjectClassFieldType'{}
%% with a type known at compile time.
%%

simplify_comps(Comps) ->
    [simplify_comp(Comp) || Comp <- Comps].

simplify_comp(#'ComponentType'{typespec=Type0}=C) ->
    Type = simplify_type(Type0),
    C#'ComponentType'{typespec=Type};
simplify_comp(Other) -> Other.

simplify_type(#type{tag=Tag,def=Inner,constraint=Constr0}=T) ->
    case Inner of
	#'ObjectClassFieldType'{type={fixedtypevaluefield,_,Type}}=OCFT ->
	    Constr = [{ocft,OCFT}|Type#type.constraint++Constr0],
	    Type#type{tag=Tag,constraint=Constr};
	_ ->
	    T
    end.

%% tablecinf_choose. A SEQUENCE or SET may be inserted in another
%% SEQUENCE or SET by the COMPONENTS OF directive. If this inserted
%% type is a referenced type that already has been checked it already
%% has its tableconstraint information. Furthermore this information
%% may be lost in the analysis in the new environment. Assume this
%% SEQUENCE/SET has a simpletable constraint and a componentrelation
%% constraint whose atlist points to the outermost component of its
%% "standalone" definition. This will cause the analysis to fail as it
%% will not find the right atlist component in the outermost
%% environment in the new inlined environment.
tablecinf_choose(SetOrSeq,false) ->
    tablecinf_choose(SetOrSeq);
tablecinf_choose(_, TableCInf) ->
    TableCInf.
tablecinf_choose(#'SET'{tablecinf=TCI}) -> 
    TCI;
tablecinf_choose(#'SEQUENCE'{tablecinf=TCI}) ->
    TCI.

get_innertag(_S,#'ObjectClassFieldType'{type=Type}) ->
    case Type of
%	#type{tag=Tag} -> Tag;
%	{fixedtypevaluefield,_,#type{tag=[]}=T} -> get_taglist(S,T);
	{fixedtypevaluefield,_,#type{tag=Tag}} -> Tag;
	{TypeFieldName,_} when is_atom(TypeFieldName) -> [];
	_ -> []
    end.
    
%% get_class_def(S, Type) -> #classdef{} | 'none'.
get_class_def(S, #typedef{typespec=#type{def=#'Externaltypereference'{}=Eref}}) ->
    {_,NextDef} = get_referenced_type(S, Eref, true),
    get_class_def(S, NextDef);
get_class_def(S, #'Externaltypereference'{}=Eref) ->
    {_,NextDef} = get_referenced_type(S, Eref, true),
    get_class_def(S, NextDef);
get_class_def(_S, #classdef{}=CD) ->
    CD;
get_class_def(_S, _) ->
    none.
    
maybe_illicit_implicit_tag(S, Kind, Tag) ->
    case Tag of
	[#tag{type='IMPLICIT'}|_T] ->
	    asn1_error(S, {implicit_tag_before,Kind});
	[ChTag = #tag{type={default,_}}|T] -> 
	    case Kind of
		open_type ->
		    [ChTag#tag{type='EXPLICIT',form=32}|T]; %X.680 30.6c, X.690 8.14.2
		choice ->
		    [ChTag#tag{type='EXPLICIT',form=32}|T] % X.680 28.6 c, 30.6c
	    end;
	_ -> 
	    Tag % unchanged
    end.


merged_mod(S,RefMod,Ext) ->
    case S of
	#state{inputmodules=[]} ->
	    RefMod;
	_ ->
	    Ext#'Externaltypereference'.module
    end.

%% maybe_open_type/2 -> #ObjectClassFieldType with updated fieldname and
%% type 
%% if the FieldRefList points out a typefield and the class don't have
%% any UNIQUE field, so that a component relation constraint cannot specify
%% the type of a typefield, return 'ASN1_OPEN_TYPE'.
%% 
maybe_open_type(_, _, #'ObjectClassFieldType'{fieldname={_,_}}=OCFT, _) ->
    %% Already converted.
    OCFT;
maybe_open_type(S, #objectclass{fields=Fs}=ClassSpec,
		#'ObjectClassFieldType'{fieldname=FieldRefList}=OCFT,
		Constr) ->
    Type = get_OCFType(S, Fs, FieldRefList),
    FieldNames = get_referenced_fieldname(FieldRefList),
    case lists:last(FieldRefList) of
	{valuefieldreference,_} ->
	    OCFT#'ObjectClassFieldType'{fieldname=FieldNames,
					type=Type};
	{typefieldreference,_} ->
	    %% Note: The constraints have not been checked yet,
	    %% so we must use a special lookup routine.
	    case {get_unique_fieldname(S, #classdef{typespec=ClassSpec}),
		  get_componentrelation(Constr)} of
		{no_unique,_} ->
		    OCFT#'ObjectClassFieldType'{fieldname=FieldNames,
						type='ASN1_OPEN_TYPE'};
		{_,no} ->
		    OCFT#'ObjectClassFieldType'{fieldname=FieldNames,
						type='ASN1_OPEN_TYPE'};
		_ ->
		    OCFT#'ObjectClassFieldType'{fieldname=FieldNames,
						type=Type}
	    end
    end.

get_componentrelation([{element_set,{componentrelation,_,_}=Cr,none}|_]) ->
    Cr;
get_componentrelation([_|T]) ->
    get_componentrelation(T);
get_componentrelation([]) ->
    no.

is_open_type(#'ObjectClassFieldType'{type='ASN1_OPEN_TYPE'}) ->
    true;
is_open_type(#'ObjectClassFieldType'{}) ->
    false.


notify_if_not_ptype(S,#pvaluesetdef{type=Type}) ->
    case Type#type.def of
	Ref when is_record(Ref,'Externaltypereference') ->
	    case get_referenced_type(S,Ref) of
		{_,#classdef{}} ->
		    throw(pobjectsetdef);
		{_,#typedef{}} ->
		    throw(pvalueset)
	    end;
	T when is_record(T,type) -> % this must be a value set
	    throw(pvalueset)
    end;
notify_if_not_ptype(_S,PT=#ptypedef{}) ->
    %% this may be a parameterized CLASS, in that case throw an
    %% asn1_class exception
    case PT#ptypedef.typespec of
	#objectclass{} -> throw({asn1_class,PT});
	_ -> ok
    end;
notify_if_not_ptype(S,#pobjectsetdef{class=Cl}) ->
    case Cl of
	#'Externaltypereference'{} ->
	    case get_referenced_type(S,Cl) of
		{_,#classdef{}} ->
		    throw(pobjectsetdef);
		{_,#typedef{}} ->
		    throw(pvalueset)
	    end;
	_ ->
	    throw(pobjectsetdef)
    end;
notify_if_not_ptype(S, PT) ->
    asn1_error(S, {param_bad_type, error_value(PT)}).

instantiate_ptype(S,Ptypedef,ParaList) ->
    #ptypedef{args=Args,typespec=Type} = Ptypedef,
    NewType = check_ptype(S,Ptypedef,Type#type{inlined=yes}),    
    MatchedArgs = match_args(S,Args, ParaList, []),
    OldArgs = S#state.parameters,
    NewS = S#state{parameters=MatchedArgs++OldArgs,abscomppath=[]},
    check_type(NewS, Ptypedef#ptypedef{typespec=NewType}, NewType).

get_datastr_name(Type) ->
    asn1ct:get_name_of_def(Type).

get_pt_args(#ptypedef{args=Args}) ->
    Args;
get_pt_args(#pvaluesetdef{args=Args}) ->
    Args;
get_pt_args(#pvaluedef{args=Args}) ->
    Args;
get_pt_args(#pobjectdef{args=Args}) ->
    Args;
get_pt_args(#pobjectsetdef{args=Args}) ->
    Args.

get_pt_spec(#ptypedef{typespec=Type}) ->
    Type;
get_pt_spec(#pvaluedef{value=Value}) ->
    Value;
get_pt_spec(#pvaluesetdef{valueset=VS}) ->
    VS;
get_pt_spec(#pobjectdef{def=Def}) ->
    Def;
get_pt_spec(#pobjectsetdef{def=Def}) ->
    Def.
	   
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% match_args(S,FormalArgs, ActualArgs, Accumulator) -> Result
%% S = #state{}
%% FormalArgs = [term()] | [{Governor,Parameter}]
%% ActualArgs = [term()]
%% Accumulator = [term()]
%% Result = [{term(),term()}] | throw()
%% Governor = #type{} | Reference | 'TYPE-IDENTIFIER' | 'ABSTRACT-SYNTAX'
%% Parameter = Reference | {Governor,Reference}
%% Reference = #'Externaltypereference'{} | #'Externalvaluerference'{}
%%
%% Different categories of parameters and governors (Dubuisson p.382) 
%% +----------------+-------------------------------+----------------------+
%% |Governor is	    | 	Parameter name style   	    |  	Parameter is	   |
%% +----------------+-------------------------------+----------------------+
%% | absent    	    |  	begins with uppercase,(bu)  |  	a type 		   |
%% |   	       	    |  	       	       	       	    |  	       		   |
%% | a type	    | 	begins with a lowercase,(bl)|  	a value		   |
%% |   	       	    |  	       	       	       	    |  	       		   |
%% | a type	    | 	begins with an uppercase    | 	a value set	   |
%% |		    | 				    |  		   	   |
%% | absent    	    |  	entirely in uppercase, (eu) |  	a class (or type)  |
%% |		    | 				    |  			   |
%% | a class name   |  	begins with a lowercase	    |  	an object      	   |
%% |		    | 				    |  		 	   |
%% | a class name   |  	begins with an uppercase    |  	an object set	   |
%% +----------------+-------------------------------+----------------------+
%%
%% Matches each of the formal parameters to corresponding actual
%% parameter, and changes format of the actual parameter according to
%% above table if necessary.
match_args(S,FA = [FormArg|Ft], AA = [ActArg|At], Acc) ->
    OldParams = S#state.parameters,
    case categorize_arg(S,FormArg,ActArg) of
	[CategorizedArg] -> 
	    match_args(S#state{parameters=
			       [{FormArg,CategorizedArg}|OldParams]},
		       Ft, At, [{FormArg,CategorizedArg}|Acc]);
	CategorizedArgs ->
	    match_args(S#state{parameters=CategorizedArgs++OldParams},
		       FA, CategorizedArgs ++ AA, Acc)
    end;
match_args(_S,[], [], Acc) ->
    lists:reverse(Acc);
match_args(S, _, _, _) ->
    asn1_error(S, param_wrong_number_of_arguments).

%%%%%%%%%%%%%%%%%
%% categorize_arg(S,FormalArg,ActualArg) -> {FormalArg,CatgorizedActualArg}
%%
categorize_arg(S,{Governor,Param},ActArg) ->
    case {governor_category(S, Governor),parameter_name_style(Param)} of
	{type,beginning_lowercase} ->		%a value
	    categorize(S, value, Governor, ActArg);
	{type,beginning_uppercase} ->		%a value set
	    categorize(ActArg);
	{{class,ClassRef},beginning_lowercase} -> 
	    categorize(S, object, ActArg, ClassRef);
	{{class,ClassRef},beginning_uppercase} ->
	    categorize(S, object_set, ActArg, ClassRef)
    end;
categorize_arg(_S, _FormalArg, ActualArg) ->
    %% Governor is absent -- must be a type or a class. We have already
    %% checked that the FormalArg begins with an uppercase letter.
    categorize(ActualArg).

%% governor_category(S, Item) -> type | {class,#'Externaltypereference'{}}
%%  Determine whether Item is a type or a class.
governor_category(S, #type{def=#'Externaltypereference'{}=Eref}) ->
    governor_category(S, Eref);
governor_category(_S, #type{}) ->
    type;
governor_category(S, #'Externaltypereference'{}=Ref) ->
    case get_class_def(S, Ref) of
	#classdef{pos=Pos,module=Mod,name=Name} ->
	    {class,#'Externaltypereference'{pos=Pos,module=Mod,type=Name}};
	none ->
	    type
    end.

%% parameter_name_style(Param,Data) -> Result
%% gets the Parameter and the name of the Data and if it exists tells
%% whether it begins with a lowercase letter or is partly or entirely
%% spelled with uppercase letters. Otherwise returns undefined
%%
parameter_name_style(#'Externaltypereference'{}) ->
    beginning_uppercase;
parameter_name_style(#'Externalvaluereference'{}) ->
    beginning_lowercase.

%% categorize(Parameter) -> CategorizedParameter
%% If Parameter has an abstract syntax of another category than
%% Category, transform it to a known syntax.
categorize({object,_,Type}) ->
    %% One example of this case is an object with a parameterized type
    %% having a locally defined type as parameter.
    Def = fun(D = #type{}) ->
		  #typedef{name = new_reference_name("type_argument"),
			   typespec = D#type{inlined=yes}};
	     ({setting,_,Eref}) when is_record(Eref,'Externaltypereference') ->
		  Eref;
	     (D) ->
		  D
	  end,
    [Def(X)||X<-Type];
categorize(#type{}=Def) ->
    [#typedef{name = new_reference_name("type_argument"),
	      typespec = Def#type{inlined=yes}}];
categorize(Def) ->
    [Def].

categorize(S,object_set,Def,ClassRef) ->
    NewObjSetSpec = 
	check_object(S,Def,#'ObjectSet'{class = ClassRef,
					set = parse_objectset(Def)}),
    Name = new_reference_name("object_set_argument"),
    [save_object_set_instance(S,Name,NewObjSetSpec)];
categorize(_S,object,Def,_ClassRef) ->
    %% should be handled
    [Def];
categorize(_S,value,_Type,Value) when is_record(Value,valuedef) ->
    [Value];
categorize(S,value,Type,Value) ->
%%    [check_value(S,#valuedef{type=Type,value=Value})].
    [#valuedef{type=Type,value=Value,module=S#state.mname}].


parse_objectset({valueset,#type{def=#'Externaltypereference'{}=Ref}}) ->
    Ref;
parse_objectset({valueset,Set}) ->
    Set;
parse_objectset(#type{def=Ref}) when is_record(Ref,'Externaltypereference') ->
    Ref;
parse_objectset(Set) ->
    %% extend this later
    Set.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%
%% Check and simplify constraints.
%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

check_constraints(_S, _HostType, []) ->
    [];
check_constraints(S, HostType0, [_|_]=Cs0) ->
    HostType = get_real_host_type(HostType0, Cs0),
    Cs1 = top_level_intersections(Cs0),
    Cs2 = [coalesce_constraints(C) || C <- Cs1],
    {_,Cs3} = filter_extensions(Cs2),
    Cs = simplify_element_sets(S, HostType, Cs3),
    finish_constraints(Cs).

get_real_host_type(HostType, Cs) ->
    case lists:keyfind(ocft, 1, Cs) of
	false -> HostType;
	{_,OCFT} -> HostType#type{def=OCFT}
    end.

top_level_intersections([{element_set,{intersection,_,_}=C,none}]) ->
    top_level_intersections_1(C);
top_level_intersections(Cs) ->
    Cs.

top_level_intersections_1({intersection,A,B}) ->
    [{element_set,A,none}|top_level_intersections_1(B)];
top_level_intersections_1(Other) ->
    [{element_set,Other,none}].

coalesce_constraints({element_set,
		  {Tag,{element_set,A,_}},
		  {Tag,{element_set,B,_}}}) ->
    %% (SIZE (C1), ..., (SIZE (C2)) => (SIZE (C1, ..., C2))
    {element_set,{Tag,{element_set,A,B}},none};
coalesce_constraints(Other) ->
    Other.

%% Remove all outermost extensions except the last.

filter_extensions([H0|T0]) ->
    case filter_extensions(T0) of
	{true,T} ->
	    H = remove_extension(H0),
	    {true,[H|T]};
	{false,T} ->
	    {any_extension(H0),[H0|T]}
    end;
filter_extensions([]) ->
    {false,[]}.

remove_extension({element_set,Root,_}) ->
    {element_set,remove_extension(Root),none};
remove_extension(Tuple) when is_tuple(Tuple) ->
    L = [remove_extension(El) || El <- tuple_to_list(Tuple)],
    list_to_tuple(L);
remove_extension(Other) -> Other.

any_extension({element_set,_,Ext}) when Ext =/= none ->
    true;
any_extension(Tuple) when is_tuple(Tuple) ->
    any_extension_tuple(1, Tuple);
any_extension(_) -> false.

any_extension_tuple(I, T) when I =< tuple_size(T) ->
    any_extension(element(I, T)) orelse any_extension_tuple(I+1, T);
any_extension_tuple(_, _) -> false.

simplify_element_sets(S, HostType, [{element_set,R0,E0}|T0]) ->
    R1 = simplify_element_set(S, HostType, R0),
    E1 = simplify_element_set(S, HostType, E0),
    case simplify_element_sets(S, HostType, T0) of
	[{element_set,R2,E2}] ->
	    [{element_set,cs_intersection(S, R1, R2),
	      cs_intersection(S, E1, E2)}];
	L when is_list(L) ->
	    [{element_set,R1,E1}|L]
    end;
simplify_element_sets(S, HostType, [H|T]) ->
    [H|simplify_element_sets(S, HostType, T)];
simplify_element_sets(_, _, []) ->
    [].

simplify_element_set(_S, _HostType, empty) ->
    {set,[]};
simplify_element_set(S, HostType, {'SingleValue',Vs0}) when is_list(Vs0) ->
    Vs1 = [resolve_value(S, HostType, V) || V <- Vs0],
    Vs = make_constr_set_vs(Vs1),
    simplify_element_set(S, HostType, Vs);
simplify_element_set(S, HostType, {'SingleValue',V0}) ->
    V1 = resolve_value(S, HostType, V0),
    V = {set,[{range,V1,V1}]},
    simplify_element_set(S, HostType, V);
simplify_element_set(S, HostType, {'ValueRange',{Lb0,Ub0}}) ->
    Lb = resolve_value(S, HostType, Lb0),
    Ub = resolve_value(S, HostType, Ub0),
    V = make_constr_set(S, Lb, Ub),
    simplify_element_set(S, HostType, V);
simplify_element_set(S, HostType, {'ALL-EXCEPT',Set0}) ->
    Set = simplify_element_set(S, HostType, Set0),
    {'ALL-EXCEPT',Set};
simplify_element_set(S, HostType, {intersection,A0,B0}) ->
    A = simplify_element_set(S, HostType, A0),
    B = simplify_element_set(S, HostType, B0),
    cs_intersection(S, A, B);
simplify_element_set(S, HostType, {union,A0,B0}) ->
    A = simplify_element_set(S, HostType, A0),
    B = simplify_element_set(S, HostType, B0),
    cs_union(S, A, B);
simplify_element_set(S, HostType, {simpletable,{element_set,Type,_}}) ->
    check_simpletable(S, HostType, Type);
simplify_element_set(S, _, {componentrelation,R,Id}) ->
    check_componentrelation(S, R, Id);
simplify_element_set(S, HostType, {Tag,{element_set,_,_}=El0}) ->
    [El1] = simplify_element_sets(S, HostType, [El0]),
    {Tag,El1};
simplify_element_set(S, HostType, #type{}=Type) ->
    simplify_element_set_type(S, HostType, Type);
simplify_element_set(_, _, C) ->
    C.

simplify_element_set_type(S, HostType, #type{def=Def0}=Type0) ->
    #'Externaltypereference'{} = Def0,		%Assertion.
    case get_referenced_type(S, Def0) of
	{_,#valuedef{checked=false,value={valueset,Vs0}}} ->
	    [Vs1] = simplify_element_sets(S, HostType, [Vs0]),
	    case Vs1 of
		{element_set,Set,none} ->
		    Set;
		{element_set,Set,{set,[]}} ->
		    Set
	    end;
	{_,{valueset,#type{def=#'Externaltypereference'{}}=Type}} ->
	    simplify_element_set_type(S, HostType, Type);
	_ ->
	    case HostType of
		#type{def=#'ObjectClassFieldType'{}} ->
		    %% Open type.
		    #type{def=Def} = check_type(S, HostType, Type0),
		    Def;
		_ ->
		    #type{constraint=Cs} = check_type(S, HostType, Type0),
		    C = convert_back(Cs),
		    simplify_element_set(S, HostType, C)
	    end
    end.

convert_back([H1,H2|T]) ->
   {intersection,H1,convert_back([H2|T])};
convert_back([H]) ->
    H;
convert_back([]) ->
    none.

check_simpletable(S, HostType, Type) ->
    case HostType of
	#type{def=#'ObjectClassFieldType'{}} ->
	    ok;
	_ ->
	    %% Table constraints may only be applied to
	    %% CLASS.&field constructs.
	    asn1_error(S, illegal_table_constraint)
    end,
    Def = case Type of
	      #type{def=D} -> D;
	      {'SingleValue',#'Externalvaluereference'{}=ObjRef} ->
		  ObjRef;
	      _ ->
		  asn1_error(S, invalid_table_constraint)
	  end,
    C = match_parameter(S, Def),
    case C of
	#'Externaltypereference'{} ->
	    ERef = check_externaltypereference(S, C),
	    {simpletable,ERef#'Externaltypereference'.type};
	#'Externalvaluereference'{} ->
	    %% This is an object set with a referenced object
	    {_,TorVDef} = get_referenced_type(S, C),
	    Set = case TorVDef of
		      #typedef{typespec=#'Object'{classname=ClassName}} ->
			  #'ObjectSet'{class=ClassName,
				       set={'SingleValue',C}};
		      #valuedef{type=#type{def=ClassDef},
				value=#'Externalvaluereference'{}=Obj} ->
			  %% an object might reference another object
			  #'ObjectSet'{class=ClassDef,
				       set={'SingleValue',Obj}}
		  end,
	    {simpletable,check_object(S, Type, Set)};
	{'ValueFromObject',{_,Object},FieldNames} ->
	    %% This is an ObjectFromObject.
	    {simpletable,extract_field(S, Object, FieldNames)}
    end.

check_componentrelation(S, {objectset,Opos,Objset0}, Id) ->
    %% Objset is an 'Externaltypereference' record, since Objset is
    %% a DefinedObjectSet.
    ObjSet = match_parameter(S, Objset0),
    Ext = check_externaltypereference(S, ObjSet),
    {componentrelation,{objectset,Opos,Ext},Id}.

%%%
%%% Internal set representation.
%%%
%%% We represent sets as a union of strictly disjoint ranges:
%%%
%%%   {set,[Range]}
%%%
%%% A range is represented as:
%%%
%%%   Range = {a_range,UpperBound} | {range,LowerBound,UpperBound}
%%%
%%% We don't use the atom 'MIN' to represent MIN, because atoms
%%% compare higher than integer. Instead we use {a_range,UpperBound}
%%% to represent MIN..UpperBound. We represent MAX as 'MAX' because
%%% 'MAX' compares higher than any integer.
%%%
%%% The ranges are sorted in term order. The ranges must not overlap
%%% or be adjacent to each other. This invariant is established when
%%% creating sets, and maintained by the intersection and union
%%% operators.
%%%
%%% Example of invalid set representaions:
%%%
%%%   [{range,0,10},{range,5,10}]    %Overlapping ranges
%%%   [{range,0,5},{range,6,10}]     %Adjancent ranges
%%%   [{range,10,20},{a_range,100}]  %Not sorted
%%%

make_constr_set(_, 'MIN', Ub) ->
    {set,[{a_range,make_constr_set_val(Ub)}]};
make_constr_set(_, Lb, Ub) when Lb =< Ub ->
    {set,[{range,make_constr_set_val(Lb),
	   make_constr_set_val(Ub)}]};
make_constr_set(S, _, _) ->
    asn1_error(S, reversed_range).

make_constr_set_val([C]) when is_integer(C) -> C;
make_constr_set_val(Val) -> Val.

make_constr_set_vs(Vs) ->
    {set,make_constr_set_vs_1(Vs)}.

make_constr_set_vs_1([]) ->
    [];
make_constr_set_vs_1([V]) ->
    [{range,V,V}];
make_constr_set_vs_1([V0|Vs]) ->
    V1 = make_constr_set_vs_1(Vs),
    range_union([{range,V0,V0}], V1).

%%%
%%% Set operators.
%%%

cs_intersection(_S, Other, none) ->
    Other;
cs_intersection(_S, none, Other) ->
    Other;
cs_intersection(_S, {set,SetA}, {set,SetB}) ->
    {set,range_intersection(SetA, SetB)};
cs_intersection(_S, A, B) ->
    {intersection,A,B}.

range_intersection([], []) ->
    [];
range_intersection([_|_], []) ->
    [];
range_intersection([], [_|_]) ->
    [];
range_intersection([H1|_]=A, [H2|_]=B) when H1 > H2 ->
    range_intersection(B, A);
range_intersection([H1|T1], [H2|T2]=B) ->
    %% Now H1 =< H2.
    case {H1,H2} of
	{{a_range,Ub0},{a_range,Ub1}} when Ub0 < Ub1 ->
	    %% Ub0 =/= 'MAX'
	    [H1|range_intersection(T1, [{range,Ub0+1,Ub1}|T2])];
	{{a_range,_},{a_range,_}} ->
	    %% Must be equal.
	    [H1|range_intersection(T1, T2)];
	{{a_range,Ub0},{range,Lb1,_Ub1}} when Ub0 < Lb1 ->
	    %% No intersection.
	    range_intersection(T1, B);
	{{a_range,Ub0},{range,Lb1,Ub1}} when Ub0 < Ub1 ->
	    %% Ub0 =/= 'MAX'
	    [{range,Lb1,Ub0}|range_intersection(T1, [{range,Ub0+1,Ub1}|T2])];
	{{a_range,Ub},{range,_Lb1,Ub}} ->
	    %% The first range covers the second range, but does not
	    %% go beyond. We handle this case specially because Ub may
	    %% be 'MAX', and evaluating 'MAX'+1 will fail.
	    [H2|range_intersection(T1, T2)];
	{{a_range,Ub0},{range,_Lb1,Ub1}} ->
	    %% Ub0 > Ub1, Ub1 =/= 'MAX'. The first range completely
	    %% covers and extends beyond the second range.
	    [H2|range_intersection([{range,Ub1+1,Ub0}|T1], T2)];
	{{range,_Lb0,Ub0},{range,Lb1,_Ub1}} when Ub0 < Lb1 ->
	    %% Lb0 < Lb1. No intersection.
	    range_intersection(T1, B);
	{{range,_Lb0,Ub0},{range,Lb1,Ub1}} when Ub0 < Ub1 ->
	    %% Ub0 >= Lb1, Ub0 =/= 'MAX'. Partial overlap.
	    [{range,Lb1,Ub0}|range_intersection(T1, [{range,Ub0+1,Ub1}|T2])];
	{{range,_Lb0,Ub},{range,_Lb1,Ub}} ->
	    %% The first range covers the second range, but does not
	    %% go beyond. We handle this case specially because Ub may
	    %% be 'MAX', and evaluating 'MAX'+1 will fail.
	    [H2|range_intersection(T1, T2)];
	{{range,_Lb0,Ub0},{range,_Lb1,Ub1}} ->
	    %% Ub1 =/= MAX. The first range completely covers and
	    %% extends beyond the second.
	    [H2|range_intersection([{range,Ub1+1,Ub0}|T1], T2)]
    end.

cs_union(_S, {set,SetA}, {set,SetB}) ->
    {set,range_union(SetA, SetB)};
cs_union(_S, A, B) ->
    {union,A,B}.

range_union(A, B) ->
    range_union_1(lists:merge(A, B)).

range_union_1([{a_range,Ub0},{a_range,Ub1}|T]) ->
    range_union_1([{a_range,max(Ub0, Ub1)}|T]);
range_union_1([{a_range,Ub0},{range,Lb1,Ub1}|T]) when Lb1-1 =< Ub0 ->
    range_union_1([{a_range,max(Ub0, Ub1)}|T]);
range_union_1([{a_range,_}=H|T]) ->
    %% Ranges are disjoint.
    [H|range_union_1(T)];
range_union_1([{range,Lb0,Ub0},{range,Lb1,Ub1}|T]) when Lb1-1 =< Ub0 ->
    range_union_1([{range,Lb0,max(Ub0, Ub1)}|T]);
range_union_1([{range,_,_}=H|T]) ->
    %% Ranges are disjoint.
    [H|range_union_1(T)];
range_union_1([]) ->
    [].

%%%
%%% Finish up constrains, making them suitable for the back-ends.
%%%
%%% A 'PermittedAlphabet' (FROM) constraint will be reduced to:
%%%
%%%   {'SingleValue',[integer()]}
%%%
%%% A 'SizeConstraint' (SIZE) constraint will be reduced to:
%%%
%%%   {Lb,Ub}
%%%
%%% All other constraints will be reduced to:
%%%
%%%   {'SingleValue',[integer()]} | {'ValueRange',Lb,Ub}
%%%

finish_constraints(Cs) ->
    finish_constraints_1(Cs, fun smart_collapse/1).

finish_constraints_1([{element_set,{Tag,{element_set,_,_}=Set0},none}|T],
		     Collapse0) ->
    Collapse = collapse_fun(Tag),
    case finish_constraints_1([Set0], Collapse) of
	[] ->
	    finish_constraints_1(T, Collapse0);
	[Set] ->
	    [{Tag,Set}|finish_constraints_1(T, Collapse0)]
    end;
finish_constraints_1([{element_set,{set,[{a_range,'MAX'}]},_}|T], Collapse) ->
    finish_constraints_1(T, Collapse);
finish_constraints_1([{element_set,{intersection,A0,B0},none}|T], Collapse) ->
    A = {element_set,A0,none},
    B = {element_set,B0,none},
    finish_constraints_1([A,B|T], Collapse);
finish_constraints_1([{element_set,Root,Ext}|T], Collapse) ->
    case finish_constraint(Root, Ext, Collapse) of
	none ->
	    finish_constraints_1(T, Collapse);
	Constr ->
	    [Constr|finish_constraints_1(T, Collapse)]
    end;
finish_constraints_1([H|T], Collapse) ->
    [H|finish_constraints_1(T, Collapse)];
finish_constraints_1([], _) ->
    [].

finish_constraint({set,Root0}, Ext, Collapse) ->
    case Collapse(Root0) of
	none -> none;
	Root -> finish_constraint(Root, Ext, Collapse)
    end;
finish_constraint(Root, Ext, _Collapse) ->
    case Ext of
	none -> Root;
	_ -> {Root,[]}
    end.

collapse_fun('SizeConstraint') ->
    fun size_constraint_collapse/1;
collapse_fun('PermittedAlphabet') ->
    fun single_value_collapse/1.

single_value_collapse(V) ->
    {'SingleValue',ordsets:from_list(single_value_collapse_1(V))}.

single_value_collapse_1([{range,Lb,Ub}|T]) when is_integer(Lb),
					      is_integer(Ub) ->
    lists:seq(Lb, Ub) ++ single_value_collapse_1(T);
single_value_collapse_1([]) ->
    [].

smart_collapse([{a_range,Ub}]) ->
    {'ValueRange',{'MIN',Ub}};
smart_collapse([{a_range,_}|T]) ->
    {range,_,Ub} = lists:last(T),
    {'ValueRange',{'MIN',Ub}};
smart_collapse([{range,Lb,Ub}]) ->
    {'ValueRange',{Lb,Ub}};
smart_collapse([_|_]=L) ->
    V = lists:foldr(fun({range,Lb,Ub}, A) ->
			    seq(Lb, Ub) ++ A
		    end, [], L),
    {'SingleValue',V}.

size_constraint_collapse([{range,0,'MAX'}]) ->
    none;
size_constraint_collapse(Root) ->
    [{range,Lb,_}|_] = Root,
    {range,_,Ub} = lists:last(Root),
    {Lb,Ub}.

seq(Same, Same) ->
    [Same];
seq(Lb, Ub) when is_integer(Lb), is_integer(Ub) ->
    lists:seq(Lb, Ub).

%%%-----------------------------------------
%% If the constraint value is a defined value the valuename
%% is replaced by the actual value
%%
resolve_value(S, HostType, Val) ->
    Id = match_parameter(S, Val),
    resolve_value1(S, HostType, Id).

resolve_value1(S, HostType, #'Externalvaluereference'{value=Name}=ERef) ->
    case resolve_namednumber(S, HostType, Name) of
	V when is_integer(V) ->
	    V;
	not_named ->
	    resolve_value1(S, HostType, get_referenced_value(S, ERef))
    end;
resolve_value1(S, HostType, {gt,V}) ->
    case resolve_value1(S, HostType, V) of
	Int when is_integer(Int) ->
	    Int + 1;
	_Other ->
	    asn1_error(S, illegal_integer_value)
    end;
resolve_value1(S, HostType, {lt,V}) ->
    case resolve_value1(S, HostType, V) of
	Int when is_integer(Int) ->
	    Int - 1;
	_Other ->
	    asn1_error(S, illegal_integer_value)
    end;
resolve_value1(S, _HostType, {'ValueFromObject',{object,Object},FieldName}) ->
    get_value_from_object(S, Object, FieldName);
resolve_value1(_, _, #valuedef{checked=true,value=V}) ->
    V;
resolve_value1(S, _, #valuedef{value={'ValueFromObject',
				     {object,Object},FieldName}}) ->
    get_value_from_object(S, Object, FieldName);
resolve_value1(S, _HostType, #valuedef{}=VDef) ->
    #valuedef{value=Val} = check_value(S,VDef),
    Val;
resolve_value1(_, _, V) ->
    V.

resolve_namednumber(S, #type{def=Def}, Name) ->
    case Def of
	{'ENUMERATED',NameList} ->
	    resolve_namednumber_1(S, Name, NameList);
	{'INTEGER',NameList} ->
	    resolve_namednumber_1(S, Name, NameList);
	_ ->
	    not_named
    end.

resolve_namednumber_1(S, Name, NameList) ->
    try
	NamedNumberList = check_enumerated(S, NameList),
	{_,N} = lookup_enum_value(S, Name, NamedNumberList),
	N
    catch _:_ ->
	    not_named
    end.

%%%
%%% End of constraint handling.
%%%

check_imported(S,Imodule,Name) ->
    check_imported(S,Imodule,Name,false).
check_imported(S,Imodule,Name,IsParsed) ->
    case asn1_db:dbget(Imodule,'MODULE') of
	undefined when IsParsed == true ->
	    ErrStr = io_lib:format("Type ~s imported from non existing module ~s~n",[Name,Imodule]),
	    error({imported,ErrStr,S});
	undefined ->
	    parse_and_save(S,Imodule),
	    check_imported(S,Imodule,Name,true);
	Im when is_record(Im,module) ->
	    case is_exported(Im,Name) of
		false ->
		    ErrStr = io_lib:format("Imported type ~s not exported from module ~s~n",[Name,Imodule]),
		    error({imported,ErrStr,S});
		_ ->
		    ok
	    end
    end,
    ok.

is_exported(Module,Name) when is_record(Module,module) ->
    {exports,Exports} = Module#module.exports,
    case Exports of
	all ->
	    true;
	[] ->
	    false;
	L when is_list(L) -> 
	    case lists:keysearch(Name,#'Externaltypereference'.type,Exports) of
		false -> false;
		_ -> true
	    end
    end.
    

check_externaltypereference(S,Etref=#'Externaltypereference'{module=Emod})->
    Currmod = S#state.mname,
    MergedMods = S#state.inputmodules,
    case Emod of
	Currmod ->
	    %% reference to current module or to imported reference
		check_reference(S,Etref);
	 _ ->
	    %% io:format("Type ~s IMPORTED FROM ~s~n",[Etype,Emod]),
	    case lists:member(Emod,MergedMods) of
		true ->
		    check_reference(S,Etref);
		false ->
		    {NewMod,_} = get_referenced_type(S,Etref),
		    Etref#'Externaltypereference'{module=NewMod}
	    end
    end.

check_reference(S,#'Externaltypereference'{pos=Pos,module=Emod,type=Name}) ->
    ModName = S#state.mname,
    case asn1_db:dbget(ModName,Name) of
	undefined ->
	    case imported(S,Name) of
		{ok,Imodule} ->
		    check_imported(S,Imodule,Name),
		    #'Externaltypereference'{module=Imodule,type=Name};
%% 		    case check_imported(S,Imodule,Name) of
%% 			ok ->
%% 			    #'Externaltypereference'{module=Imodule,type=Name};
%% 			Err ->
%% 			    Err
%% 		    end;
		_ ->
		    %may be a renamed type in multi file compiling!
		    {M,T}=get_renamed_reference(S,Name,Emod),
		    NewName = asn1ct:get_name_of_def(T),
		    NewPos = asn1ct:get_pos_of_def(T),
		    #'Externaltypereference'{pos=NewPos,
					     module=M,
					     type=NewName}
	    end;
	_ ->
	    %% cannot do check_type here due to recursive definitions, like
	    %% S ::= SEQUENCE {a INTEGER, b S}. This implies that references
	    %% that appear before the definition will be an 
	    %% Externaltypereference in the abstract syntax tree
	    #'Externaltypereference'{pos=Pos,module=ModName,type=Name}
    end.

get_referenced_value(S, T) ->
    case get_referenced_type(S, T) of
	{ExtMod,#valuedef{value=#'Externalvaluereference'{}=Ref}} ->
	    get_referenced_value(update_state(S, ExtMod), Ref);
	{_,#valuedef{value=Val}} ->
	    Val
    end.

get_referenced_type(S, T) ->
    get_referenced_type(S, T, false).

get_referenced_type(S, T, Recurse) ->
    case do_get_referenced_type(S, T) of
	{_,#typedef{typespec=#type{def=#'Externaltypereference'{}=ERef}}}
	  when Recurse ->
	    get_referenced_type(S, ERef, Recurse);
	{_,_}=Res ->
	    Res
    end.

do_get_referenced_type(S, T0) ->
    case match_parameter(S, T0) of
	T0 ->
	    do_get_ref_type_1(S, T0);
	T ->
	    do_get_referenced_type(S, T)
    end.

do_get_ref_type_1(S, #'Externaltypereference'{pos=P,
					      module=M,
					      type=T}) ->
    do_get_ref_type_2(S, P, M, T);
do_get_ref_type_1(S, #'Externalvaluereference'{pos=P,
					       module=M,
					       value=V}) ->
    do_get_ref_type_2(S, P, M, V);
do_get_ref_type_1(_, T) ->
    {undefined,T}.

do_get_ref_type_2(#state{mname=Current,inputmodules=Modules}=S,
		  Pos, M, T) ->
    case M =:= Current orelse lists:member(M, Modules) of
	true ->
	    get_referenced1(S, M, T, Pos);
	false ->
	    get_referenced(S, M, T, Pos)
    end.

%% get_referenced/3
%% The referenced entity Ename may in case of an imported parameterized
%% type reference imported entities in the other module, which implies that
%% asn1_db:dbget will fail even though the referenced entity exists. Thus
%% Emod may be the module that imports the entity Ename and not holds the
%% data about Ename. 
get_referenced(S,Emod,Ename,Pos) ->
    ?dbg("get_referenced: ~p~n",[Ename]),
    parse_and_save(S,Emod),
    ?dbg("get_referenced,parse_and_save ~n",[]),
    case asn1_db:dbget(Emod,Ename) of
	undefined ->
	    %% May be an imported entity in module Emod or Emod may not exist
	    case asn1_db:dbget(Emod,'MODULE') of
		undefined ->
		    asn1_error(S, {undefined_import, Ename, Emod});
		_ ->
		    NewS = update_state(S,Emod),
		    get_imported(NewS,Ename,Emod,Pos)
	    end;
	T when is_record(T,typedef) ->
	    ?dbg("get_referenced T: ~p~n",[T]),
	    {Emod,T};	    % should add check that T is exported here
	V ->
	    ?dbg("get_referenced V: ~p~n",[V]),
	    {Emod,V}
    end.

get_referenced1(S,ModuleName,Name,Pos) ->
    case asn1_db:dbget(S#state.mname,Name) of
	undefined ->
	    %% ModuleName may be other than S#state.mname when 
	    %% multi file compiling is used.
	    get_imported(S,Name,ModuleName,Pos);
	T ->
	    {S#state.mname,T}
    end.

get_imported(S,Name,Module,Pos) ->
    ?dbg("get_imported, Module: ~p, Name: ~p~n",[Module,Name]),
    case imported(S,Name) of
	{ok,Imodule} ->
	    parse_and_save(S,Imodule),
	    case asn1_db:dbget(Imodule,'MODULE') of
		undefined ->
		    asn1_error(S, {undefined_import, Name, Module});
		Im when is_record(Im,module) ->
		    case is_exported(Im,Name) of
			false ->
			    asn1_error(S, {undefined_export, Name});
			_ ->
			    ?dbg("get_imported, is_exported ~p, ~p~n",[Imodule,Name]),
			    get_referenced_type(S,
						#'Externaltypereference'
						{module=Imodule,
						 type=Name,pos=Pos})
		    end
	    end;
	_ ->
	    get_renamed_reference(S,Name,Module)
    end.

save_object_set_instance(S,Name,ObjSetSpec) 
  when is_record(ObjSetSpec,'ObjectSet') ->
    NewObjSet = #typedef{checked=true,name=Name,typespec=ObjSetSpec},
    asn1_db:dbput(S#state.mname,Name,NewObjSet),
    case ObjSetSpec of
	#'ObjectSet'{uniquefname={unique,undefined}} ->
	    ok;
	_ ->
	    %% Should be generated iff 
	    %% ObjSpec#'ObjectSet'.uniquefname /= {unique,undefined}
	    ObjSetKey = {Name,objectset,NewObjSet},
	    %% asn1ct_gen:insert_once(parameterized_objects,ObjSetKey)
	    insert_once(S,parameterized_objects,ObjSetKey)
    end,
    #'Externaltypereference'{module=S#state.mname,type=Name}.
    
%% load_asn1_module do not check that the module is saved.
%% If get_referenced_type is called before the module must
%% be saved. 
load_asn1_module(#state{mname=M,module=Mod},M)->
    Mod;
load_asn1_module(_,M) ->
    asn1_db:dbget(M,'MODULE').

parse_and_save(S,Module) when is_record(S,state) ->
    Erule = S#state.erule,
    case asn1db_member(S,Erule,Module) of
	true ->
	    ok;
	_ ->
	    case asn1ct:parse_and_save(Module,S) of
		ok ->
		    save_asn1db_uptodate(S,Erule,Module);    
		Err ->
		    Err
	    end
    end.

asn1db_member(S,Erule,Module) ->
    Asn1dbUTL = get_asn1db_uptodate(S),
    lists:member({Erule,Module},Asn1dbUTL).

save_asn1db_uptodate(S,Erule,Module) ->
    Asn1dbUTL = get_asn1db_uptodate(S),
    Asn1dbUTL2 = lists:keydelete(Module,2,Asn1dbUTL),
    put_asn1db_uptodate([{Erule,Module}|Asn1dbUTL2]).
	    
get_asn1db_uptodate(S) ->
    case get(asn1db_uptodate) of
	undefined -> [{S#state.erule,S#state.mname}]; %initialize
	L -> L
    end.

put_asn1db_uptodate(L) ->
    put(asn1db_uptodate,L).

update_state(S,undefined) ->
    S;
update_state(S=#state{mname=ModuleName},ModuleName) ->
    S;
update_state(S,ModuleName) ->
    case lists:member(ModuleName,S#state.inputmodules) of
	true ->
	    S;
	_ ->
	    parse_and_save(S,ModuleName),
	    Mod = #module{} = asn1_db:dbget(ModuleName,'MODULE'),
	    S#state{mname=ModuleName,module=Mod}
    end.

get_renamed_reference(S,Name,Module) ->
    case renamed_reference(S,Name,Module) of
	undefined ->
	    asn1_error(S, {undefined, Name});
	NewTypeName when NewTypeName =/= Name ->
	    get_referenced1(S,Module,NewTypeName,undefined)
    end.
renamed_reference(S,#'Externaltypereference'{type=Name,module=Module}) ->
    case renamed_reference(S,Name,Module) of
	undefined ->
	    Name;
	Other ->
	    Other
    end.
renamed_reference(S,Name,Module) ->
    %% first check if there is a renamed type in this module
    %% second check if any type was imported with this name
    case asn1ct_table:exists(renamed_defs) of
	false -> undefined;
	true ->
	    case asn1ct_table:match(renamed_defs, {'$1',Name,Module}) of
		[] -> 
		    case asn1ct_table:exists(original_imports) of
			false ->
			    undefined;
			true  ->
			    case asn1ct_table:match(original_imports, {Module,'$1'}) of
				[] ->
				    undefined;
				[[ImportsList]] ->
				    case get_importmoduleoftype(ImportsList,Name) of
					undefined ->
					    undefined;
					NextMod ->
					    renamed_reference(S,Name,NextMod)
				    end
			    end
		    end;
		[[NewTypeName]] ->
		    NewTypeName
	    end
    end.

get_importmoduleoftype([I|Is],Name) ->
    Index = #'Externaltypereference'.type,
    case lists:keysearch(Name,Index,I#'SymbolsFromModule'.symbols) of
	{value,_Ref} ->
	    (I#'SymbolsFromModule'.module)#'Externaltypereference'.type;
	_ ->
	    get_importmoduleoftype(Is,Name)
    end;
get_importmoduleoftype([],_) ->
    undefined.
		     
match_parameters(S, Names) ->
    [match_parameter(S, Name) || Name <- Names].

match_parameter(#state{parameters=Ps}=S, Name) ->
    match_parameter(S, Name, Ps).

match_parameter(_S, Name, []) ->
    Name;
match_parameter(S, {valueset,{element_set,#type{}=Ts,none}}, Ps) ->
    match_parameter(S, {valueset,Ts}, Ps);
match_parameter(_S, #'Externaltypereference'{type=Name},
		[{#'Externaltypereference'{type=Name},NewName}|_T]) ->
    NewName;
match_parameter(_S, #'Externaltypereference'{type=Name},
		[{{_,#'Externaltypereference'{type=Name}},NewName}|_T]) ->
    NewName;
match_parameter(_S, #'Externalvaluereference'{value=Name},
		[{#'Externalvaluereference'{value=Name},NewName}|_T]) ->
    NewName;
match_parameter(_S, #'Externalvaluereference'{value=Name},
		[{{_,#'Externalvaluereference'{value=Name}},NewName}|_T]) ->
    NewName;
match_parameter(_S, #type{def=#'Externaltypereference'{module=M,type=Name}},
		[{#'Externaltypereference'{module=M,type=Name},Type}]) ->
    Type;
match_parameter(_S, {valueset,#type{def=#'Externaltypereference'{type=Name}}},
		[{{_,#'Externaltypereference'{type=Name}},
		  {valueset,#type{def=NewName}}}|_T]) ->
    NewName;
match_parameter(_S, {valueset,#type{def=#'Externaltypereference'{type=Name}}},
		[{{_,#'Externaltypereference'{type=Name}},
		  NewName=#type{def=#'Externaltypereference'{}}}|_T]) ->
    NewName#type.def;
match_parameter(_S, {valueset,#type{def=#'Externaltypereference'{type=Name}}},
		[{{_,#'Externaltypereference'{type=Name}},NewName}|_T]) ->
    NewName;
%% When a parameter is a parameterized element it has to be
%% instantiated now!
match_parameter(S, {valueset,T=#type{def={pt,_,_Args}}}, _Ps) ->
    try check_type(S,#typedef{name=S#state.tname,typespec=T},T) of
	#type{def=Ts} ->
	    Ts
    catch pobjectsetdef ->
 	    {_,ObjRef,_Params} = T#type.def,
 	    {_,ObjDef}=get_referenced_type(S,ObjRef),
	    %%ObjDef is a pvaluesetdef where the type field holds the class
	    ClassRef = 
		case ObjDef of
		    #pvaluesetdef{type=TDef} ->
			TDef#type.def;
		    #pobjectsetdef{class=ClRef} -> ClRef
		end,
	    %% The reference may not have the home module of the class
	    {HomeMod,_} = get_referenced_type(S,ClassRef),
	    RightClassRef = 
		ClassRef#'Externaltypereference'{module=HomeMod},

	    ObjectSet = #'ObjectSet'{class=RightClassRef,set=T},
 	    ObjSpec = check_object(S,#typedef{typespec=ObjectSet},ObjectSet),
	    Name = list_to_atom(asn1ct_gen:list2name([get_datastr_name(ObjDef)|S#state.recordtopname])),	 
	    save_object_set_instance(S,Name,ObjSpec)
    end;

%% same as previous, only depends on order of parsing
match_parameter(S, {valueset,{pos,{objectset,_,POSref},Args}}, Ps) ->
    match_parameter(S, {valueset,#type{def={pt,POSref,Args}}}, Ps);
match_parameter(S, Name, [_H|T]) ->
    %%io:format("match_parameter(~p,~p)~n",[Name,[H|T]]),
    match_parameter(S, Name, T).

imported(S,Name) ->
    {imports,Ilist} = (S#state.module)#module.imports,
    imported1(Name,Ilist).

imported1(Name,
	  [#'SymbolsFromModule'{symbols=Symlist,
				module=#'Externaltypereference'{type=ModuleName}}|T]) ->
    case lists:keysearch(Name,#'Externaltypereference'.type,Symlist) of
	{value,_V} ->
	    {ok,ModuleName};
	_ ->
	    imported1(Name,T)
    end;
imported1(_Name,[]) ->
    false.

%% Check the named number list for an INTEGER or a BIT STRING.
check_named_number_list(_S, []) ->
    [];
check_named_number_list(_S, [{_,_}|_]=NNL) ->
    %% The named number list has already been checked.
    NNL;
check_named_number_list(S, NNL0) ->
    %% Check that the names are unique.
    case check_unique(NNL0, 2) of
	[] ->
	    NNL1 = [{Id,resolve_valueref(S, Val)} || {'NamedNumber',Id,Val} <- NNL0],
	    NNL = lists:keysort(2, NNL1),
	    case check_unique(NNL, 2) of
		[] ->
		    NNL;
		[Val|_] ->
		    asn1_error(S, {value_reused,Val})
	    end;
	[H|_] ->
	    asn1_error(S, {namelist_redefinition,H})
    end.

resolve_valueref(S, #'Externalvaluereference'{} = T) ->
    get_referenced_value(S, T);
resolve_valueref(_, Val) when is_integer(Val) ->
    Val.

check_integer(S, NNL) ->
    check_named_number_list(S, NNL).

check_bitstring(S, NNL0) ->
    NNL = check_named_number_list(S, NNL0),
    _ = [asn1_error(S, {invalid_bit_number,Bit}) ||
	    {_,Bit} <- NNL, Bit < 0],
    NNL.

check_real(_S,_Constr) ->
    ok.
    
%% Check INSTANCE OF
%% check that DefinedObjectClass is of TYPE-IDENTIFIER class
%% If Constraint is empty make it the general INSTANCE OF type
%% If Constraint is not empty make an inlined type
%% convert INSTANCE OF to the associated type
check_instance_of(S,DefinedObjectClass,Constraint) ->
    check_type_identifier(S,DefinedObjectClass),
    iof_associated_type(S,Constraint).
    
check_type_identifier(S, Eref=#'Externaltypereference'{type=Class}) ->
    case get_referenced_type(S, Eref) of
	{_,#classdef{name='TYPE-IDENTIFIER'}} ->
	    ok;
	{_,#classdef{typespec=#'Externaltypereference'{}=NextEref}} ->
	    check_type_identifier(S, NextEref);
	{_,TD=#typedef{typespec=#type{def=#'Externaltypereference'{}}}} ->
	    check_type_identifier(S, (TD#typedef.typespec)#type.def);
	_ ->
	    asn1_error(S, {illegal_instance_of,Class})
    end.

iof_associated_type(S,[]) ->
    %% in this case encode/decode functions for INSTANCE OF must be
    %% generated
    case get(instance_of) of
	undefined ->
	    AssociateSeq = iof_associated_type1(S,[]),
	    Tag = [?TAG_CONSTRUCTED(?N_INSTANCE_OF)],
	    TypeDef=#typedef{checked=true,
			     name='INSTANCE OF',
			     typespec=#type{tag=Tag,
					    def=AssociateSeq}},
	    asn1_db:dbput(S#state.mname,'INSTANCE OF',TypeDef),
	    instance_of_decl(S#state.mname);
%%	    put(instance_of,{generate,S#state.mname});
	_ ->
	    instance_of_decl(S#state.mname),
	    ok
    end,
    #'Externaltypereference'{module=S#state.mname,type='INSTANCE OF'};
iof_associated_type(S,C) ->
    iof_associated_type1(S,C).

iof_associated_type1(S,C) ->
    {TableCInf,Comp1Cnstr,Comp2Cnstr,Comp2tablecinf}=
	instance_of_constraints(S,C),

    ModuleName = S#state.mname,
    Typefield_type=
	case C of
	    [] -> 'ASN1_OPEN_TYPE';
	    _ -> {typefield,'Type'}
	end,
    ObjIdTag = [{'UNIVERSAL',8}],
    C1TypeTag = [#tag{class='UNIVERSAL',
		      number=6,
		      type='IMPLICIT',
		      form=0}],
    TypeIdentifierRef=#'Externaltypereference'{module=ModuleName,
					       type='TYPE-IDENTIFIER'},
    ObjectIdentifier =
	#'ObjectClassFieldType'{classname=TypeIdentifierRef,
				class=[],
%%				fieldname=[{valuefieldreference,id}],
				fieldname={id,[]},
				type={fixedtypevaluefield,id,
				      #type{def='OBJECT IDENTIFIER'}}},
    Typefield =
	#'ObjectClassFieldType'{classname=TypeIdentifierRef,
				class=[],
%%				fieldname=[{typefieldreference,'Type'}],
				fieldname={'Type',[]},
				type=Typefield_type},
    IOFComponents0 =
	[#'ComponentType'{name='type-id',
			  typespec=#type{tag=C1TypeTag,
					 def=ObjectIdentifier,
					 constraint=Comp1Cnstr},
			  prop=mandatory,
			  tags=ObjIdTag},
	 #'ComponentType'{name=value,
			  typespec=#type{tag=[#tag{class='CONTEXT',
						   number=0,
						   type='EXPLICIT',
						   form=32}],
					 def=Typefield,
					 constraint=Comp2Cnstr,
					 tablecinf=Comp2tablecinf},
			  prop=mandatory,
			  tags=[{'CONTEXT',0}]}],
    IOFComponents = textual_order(IOFComponents0),
    #'SEQUENCE'{tablecinf=TableCInf,
		components=simplify_comps(IOFComponents)}.
	   

%% returns the leading attribute, the constraint of the components and
%% the tablecinf value for the second component.
instance_of_constraints(_, []) ->
    {false,[],[],[]};
instance_of_constraints(S, [{element_set,{simpletable,C},none}]) ->
    {element_set,Type,none} = C,
    instance_of_constraints_1(S, Type).

instance_of_constraints_1(S, Type) ->
    #type{def=#'Externaltypereference'{type=Name}} = Type,
    ModuleName = S#state.mname,
    ObjectSetRef=#'Externaltypereference'{module=ModuleName,
					  type=Name},
    CRel=[{componentrelation,{objectset,
			      undefined, %% pos
			      ObjectSetRef},
			      [{innermost,
				[#'Externalvaluereference'{module=ModuleName,
							   value=type}]}]}],
    Mod = S#state.mname,
    TableCInf=#simpletableattributes{objectsetname={Mod,Name},
				     c_name='type-id',
				     c_index=1,
				     usedclassfield=id,
				     uniqueclassfield=id,
				     valueindex=[]},
    {TableCInf,[{simpletable,Name}],CRel,[{objfun,ObjectSetRef}]}.

%%%
%%% Check ENUMERATED.
%%%

check_enumerated(_S, [{Name,Number}|_]=NNL)
  when is_atom(Name), is_integer(Number) ->
    %% Already checked.
    NNL;
check_enumerated(_S, {[{Name,Number}|_],L}=NNL)
  when is_atom(Name), is_integer(Number), is_list(L) ->
    %% Already checked (with extension).
    NNL;
check_enumerated(S, NNL) ->
    check_enum_ids(S, NNL, gb_sets:empty()),
    check_enum(S, NNL, gb_sets:empty(), []).

check_enum_ids(S, [{'NamedNumber',Id,_}|T], Ids0) ->
    Ids = check_enum_update_ids(S, Id, Ids0),
    check_enum_ids(S, T, Ids);
check_enum_ids(S, ['EXTENSIONMARK'|T], Ids) ->
    check_enum_ids(S, T, Ids);
check_enum_ids(S, [Id|T], Ids0) when is_atom(Id) ->
    Ids = check_enum_update_ids(S, Id, Ids0),
    check_enum_ids(S, T, Ids);
check_enum_ids(_, [], _) ->
    ok.

check_enum(S, [{'NamedNumber',Id,N}|T], Used0, Acc) ->
    Used = check_enum_update_used(S, Id, N, Used0),
    check_enum(S, T, Used, [{Id,N}|Acc]);
check_enum(S, ['EXTENSIONMARK'|Ext0], Used0, Acc0) ->
    Acc = lists:reverse(Acc0),
    {Root,Used,Cnt} = check_enum_number_root(Acc, Used0, 0, []),
    Ext = check_enum_ext(S, Ext0, Used, Cnt, []),
    {Root,Ext};
check_enum(S, [Id|T], Used, Acc) when is_atom(Id) ->
    check_enum(S, T, Used, [Id|Acc]);
check_enum(_, [], Used, Acc0) ->
    Acc = lists:reverse(Acc0),
    {Root,_,_} = check_enum_number_root(Acc, Used, 0, []),
    lists:keysort(2, Root).

check_enum_number_root([Id|T]=T0, Used0, Cnt, Acc) when is_atom(Id) ->
    case gb_sets:is_element(Cnt, Used0) of
	false ->
	    Used = gb_sets:insert(Cnt, Used0),
	    check_enum_number_root(T, Used, Cnt+1, [{Id,Cnt}|Acc]);
	true ->
	    check_enum_number_root(T0, Used0, Cnt+1, Acc)
    end;
check_enum_number_root([H|T], Used, Cnt, Acc) ->
    check_enum_number_root(T, Used, Cnt, [H|Acc]);
check_enum_number_root([], Used, Cnt, Acc) ->
    {lists:keysort(2, Acc),Used,Cnt}.

check_enum_ext(S, [{'NamedNumber',Id,N}|T], Used0, C, Acc) ->
    Used = check_enum_update_used(S, Id, N, Used0),
    if
	N < C ->
	    asn1_error(S, {enum_not_ascending,Id,N,C-1});
	true ->
	    ok
    end,
    check_enum_ext(S, T, Used, N+1, [{Id,N}|Acc]);
check_enum_ext(S, [Id|T]=T0, Used0, C, Acc) when is_atom(Id) ->
    case gb_sets:is_element(C, Used0) of
	true ->
	    check_enum_ext(S, T0, Used0, C+1, Acc);
	false ->
	    Used = gb_sets:insert(C, Used0),
	    check_enum_ext(S, T, Used, C+1, [{Id,C}|Acc])
    end;
check_enum_ext(_, [], _, _, Acc) ->
    lists:keysort(2, Acc).

check_enum_update_ids(S, Id, Ids) ->
    case gb_sets:is_element(Id, Ids) of
	false ->
	    gb_sets:insert(Id, Ids);
	true ->
	    asn1_error(S, {enum_illegal_redefinition,Id})
    end.

check_enum_update_used(S, Id, N, Used) ->
    case gb_sets:is_element(N, Used) of
	false ->
	    gb_sets:insert(N, Used);
	true ->
	    asn1_error(S, {enum_reused_value,Id,N})
    end.

%%%
%%% End of ENUMERATED checking.
%%%

check_boolean(_S,_Constr) ->
    ok.

check_octetstring(_S,_Constr) ->
    ok.

% check all aspects of a SEQUENCE
% - that all component names are unique
% - that all TAGS are ok (when TAG default is applied)
% - that each component is of a valid type
% - that the extension marks are valid

check_sequence(S,Type,Comps)  ->
    Components = expand_components(S,Comps),    
    case check_unique([C||C <- Components ,is_record(C,'ComponentType')]
		      ,#'ComponentType'.name) of
	[] ->
	    %% sort_canonical(Components),
	    Components2 = maybe_automatic_tags(S,Components),
	    %% check the table constraints from here. The outermost type
	    %% is Type, the innermost is Comps (the list of components)
	    NewComps = check_each_component2(S,Type,Components2),
	    check_unique_sequence_tags(S,NewComps),

	    %% CRelInf is the "leading attribute" information
	    %% necessary for code generating of the look up in the
	    %% object set table,
	    %% i.e. getenc_ObjectSet/getdec_ObjectSet.
	    %% {objfun,ERef} tuple added in NewComps2 in tablecinf
	    %% field in type record of component relation constrained
	    %% type
	    {CRelInf,NewComps2} = componentrelation_leadingattr(S,NewComps),

	    %% CompListWithTblInf has got a lot unecessary info about
	    %% the involved class removed, as the class of the object
	    %% set.
	    CompListWithTblInf = get_tableconstraint_info(S,Type,NewComps2),

	    NewComps3 = textual_order(CompListWithTblInf),
	    NewComps4 = simplify_comps(NewComps3),
	    CompListTuple = complist_as_tuple(NewComps4),
	    {CRelInf,CompListTuple};
	Dupl ->
	    asn1_error(S, {duplicate_identifier, error_value(hd(Dupl))})
    end.

complist_as_tuple(CompList) ->
    complist_as_tuple(CompList, [], [], [], root).

complist_as_tuple([#'EXTENSIONMARK'{}|T], Acc, Ext, Acc2, root) ->
    complist_as_tuple(T, Acc, Ext, Acc2, ext);
complist_as_tuple([#'EXTENSIONMARK'{}|T], Acc, Ext, Acc2, ext) ->
    complist_as_tuple(T, Acc, Ext, Acc2, root2);
complist_as_tuple([C|T], Acc, Ext, Acc2, root) ->
    complist_as_tuple(T, [C|Acc], Ext, Acc2, root);
complist_as_tuple([C|T], Acc, Ext, Acc2, ext) ->
    complist_as_tuple(T, Acc, [C|Ext], Acc2, ext);
complist_as_tuple([C|T], Acc, Ext, Acc2, root2) ->
    complist_as_tuple(T, Acc, Ext, [C|Acc2], root2);
complist_as_tuple([], Acc, _Ext, _Acc2, root) ->
    lists:reverse(Acc);
complist_as_tuple([], Acc, Ext, _Acc2, ext) ->
    {lists:reverse(Acc),lists:reverse(Ext)};
complist_as_tuple([], Acc, Ext, Acc2, root2) ->
    {lists:reverse(Acc),lists:reverse(Ext),lists:reverse(Acc2)}.

expand_components(S, [{'COMPONENTS OF',Type}|T]) ->
    CompList = expand_components2(S,get_referenced_type(S,Type#type.def)),
    expand_components(S,CompList) ++ expand_components(S,T);
expand_components(S,[H|T]) ->
    [H|expand_components(S,T)];
expand_components(_,[]) ->
    [].
expand_components2(_S,{_,#typedef{typespec=#type{def=Seq}}}) 
  when is_record(Seq,'SEQUENCE') ->
    case Seq#'SEQUENCE'.components of
	{R1,_Ext,R2} -> R1 ++ R2;
	{Root,_Ext} -> Root;
	Root -> take_only_rootset(Root)
    end;
expand_components2(_S,{_,#typedef{typespec=#type{def=Set}}})
  when is_record(Set,'SET') ->
    case Set#'SET'.components of
	{R1,_Ext,R2} -> R1 ++ R2;
	{Root,_Ext} -> Root;
	Root -> take_only_rootset(Root)
    end;
expand_components2(_S,{_,#typedef{typespec=RefType=#type{def=#'Externaltypereference'{}}}}) ->
    [{'COMPONENTS OF',RefType}];
expand_components2(S,{_,PT={pt,_,_}}) ->
    PTType = check_type(S,PT,#type{def=PT}),
    expand_components2(S,{dummy,#typedef{typespec=PTType}});
expand_components2(S,{_,OCFT = #'ObjectClassFieldType'{}}) ->
    UncheckedType = #type{def=OCFT},
    Type = check_type(S,#typedef{typespec=UncheckedType},UncheckedType),
    expand_components2(S, {undefined,ocft_def(Type)});
expand_components2(S,{_,ERef}) when is_record(ERef,'Externaltypereference') ->
    expand_components2(S,get_referenced_type(S,ERef));
expand_components2(S,{_, What}) ->
    asn1_error(S, {illegal_COMPONENTS_OF, error_value(What)}).

take_only_rootset([])->
    [];
take_only_rootset([#'EXTENSIONMARK'{}|_T])->
    [];
take_only_rootset([H|T]) ->
    [H|take_only_rootset(T)].

check_unique_sequence_tags(S,CompList) ->
    TagComps = case complist_as_tuple(CompList) of
		   {R1,Ext,R2} ->
		       R1 ++ [C#'ComponentType'{prop='OPTIONAL'}||
				 C = #'ComponentType'{} <- Ext]++R2;
		   {R1,Ext} ->
		       R1 ++ [C#'ComponentType'{prop='OPTIONAL'}||
				 C = #'ComponentType'{} <- Ext];
		   _ ->
		       CompList
	       end,
    check_unique_sequence_tags0(S,TagComps).

check_unique_sequence_tags0(S,[#'ComponentType'{prop=mandatory}|Rest]) ->
    check_unique_sequence_tags0(S,Rest);
check_unique_sequence_tags0(S,[C=#'ComponentType'{}|Rest]) ->
    check_unique_sequence_tags1(S,Rest,[C]);% optional or default
check_unique_sequence_tags0(S,[_ExtensionMarker|Rest]) ->
    check_unique_sequence_tags0(S,Rest);
check_unique_sequence_tags0(_S,[]) ->
    true.

check_unique_sequence_tags1(S,[C|Rest],Acc) when is_record(C,'ComponentType') ->
    case C#'ComponentType'.prop of
	mandatory ->
	    check_unique_tags(S,lists:reverse([C|Acc])),
	    check_unique_sequence_tags(S,Rest);
	_  ->
	    check_unique_sequence_tags1(S,Rest,[C|Acc]) % default or optional
    end;
check_unique_sequence_tags1(S,[H|Rest],Acc) ->
    check_unique_sequence_tags1(S,Rest,[H|Acc]);
check_unique_sequence_tags1(S,[],Acc) ->
    check_unique_tags(S,lists:reverse(Acc)).

check_sequenceof(S,Type,Component) when is_record(Component,type) ->
    simplify_type(check_type(S, Type, Component)).

check_set(S,Type,Components) ->
    {TableCInf,NewComponents} = check_sequence(S,Type,Components),
    check_unique_tags(S, collect_components(NewComponents), []),
    case {lists:member(der,S#state.options),S#state.erule} of
	{true,_} ->
	    {Sorted,SortedComponents} = sort_components(der,S,NewComponents),
	    {Sorted,TableCInf,SortedComponents};
	{_,PER} when PER =:= per; PER =:= uper ->
	    {Sorted,SortedComponents} = sort_components(per,S,NewComponents),
	    {Sorted,TableCInf,SortedComponents};
	_ ->
	    {false,TableCInf,NewComponents}
    end.

collect_components({C1,C2,C3}) ->
    collect_components(C1++C2++C3);
collect_components({C1,C2}) ->
    collect_components(C1++C2);
collect_components(Cs) ->
    %% Assert that tags are not empty
    [] = [EmptyTag || EmptyTag = #'ComponentType'{tags=[]} <- Cs],
    Cs.

%% sorting in canonical order according to X.680 8.6, X.691 9.2
%% DER: all components shall be sorted in canonical order.
%% PER: only root components shall be sorted in canonical order. The
%%      extension components shall remain in textual order.
%%
sort_components(der, S, Components) ->
    {R1,Ext,R2} = extension(textual_order(Components)),
    CompsList = case Ext of
		    noext -> R1;
		    _ -> R1 ++ Ext ++ R2
		end,
    case {untagged_choice(S,CompsList),Ext} of
	{false,noext} ->
	    {true,sort_components1(CompsList)};
	{false,_} ->
	    {true,{sort_components1(CompsList),[]}};
	{true,noext} ->
	    %% sort in run-time
	    {dynamic,R1};
	_ ->
	    {dynamic,{R1, Ext, R2}}
    end;
sort_components(per, S, Components) ->
    {R1,Ext,R2} = extension(textual_order(Components)),
    Root = tag_untagged_choice(S,R1++R2),
    case Ext of
	noext ->
	    {true,sort_components1(Root)};
	_ ->
	    {true,{sort_components1(Root),Ext}}
    end.

sort_components1(Cs0) ->
    Cs1 = [{tag_key(Tag),C} || #'ComponentType'{tags=[Tag|_]}=C <- Cs0],
    Cs = lists:sort(Cs1),
    [C || {_,C} <- Cs].

tag_key({'UNIVERSAL',Tag}) ->   {0,Tag};
tag_key({'APPLICATION',Tag}) -> {1,Tag};
tag_key({'CONTEXT',Tag}) ->     {2,Tag};
tag_key({'PRIVATE',Tag}) ->     {3,Tag}.

untagged_choice(_S,[#'ComponentType'{typespec=#type{tag=[],def={'CHOICE',_}}}|_Rest]) ->
    true;
untagged_choice(S,[#'ComponentType'{typespec=#type{tag=[],def=ExRef}}|Rest])
  when is_record(ExRef,'Externaltypereference')->
    case get_referenced_type(S,ExRef) of
	{_,#typedef{typespec=#type{tag=[],
				   def={'CHOICE',_}}}} -> true;
	_ -> untagged_choice(S,Rest)
    end;
untagged_choice(S,[_|Rest]) ->
    untagged_choice(S,Rest);
untagged_choice(_,[]) ->
    false.
    
    
tag_untagged_choice(S,Cs) ->
    tag_untagged_choice(S,Cs,[]).
tag_untagged_choice(S,[C = #'ComponentType'{typespec=#type{tag=[],def={'CHOICE',_}}}|Rest],Acc) ->
    TagList = C#'ComponentType'.tags,
    TaggedC = C#'ComponentType'{tags=get_least_tag(TagList)},
    tag_untagged_choice(S,Rest,[TaggedC|Acc]);
tag_untagged_choice(S,[C = #'ComponentType'{typespec=#type{tag=[],def=ExRef}}|Rest],Acc) when is_record(ExRef,'Externaltypereference') ->
    case get_referenced_type(S,ExRef) of
	{_,#typedef{typespec=#type{tag=[],
				   def={'CHOICE',_}}}} -> 
	    TagList = C#'ComponentType'.tags,
	    TaggedC = C#'ComponentType'{tags = get_least_tag(TagList)},
	    tag_untagged_choice(S,Rest,[TaggedC|Acc]);
	_ -> 
	    tag_untagged_choice(S,Rest,[C|Acc])
    end;
tag_untagged_choice(S,[C|Rest],Acc) ->
    tag_untagged_choice(S,Rest,[C|Acc]);
tag_untagged_choice(_S,[],Acc) ->
    Acc.
get_least_tag([]) ->
    [];
get_least_tag(TagList) ->
    %% The smallest tag 'PRIVATE' < 'CONTEXT' < 'APPLICATION' < 'UNIVERSAL'
    Pred = fun({'PRIVATE',_},{'CONTEXT',_}) -> true;
	      ({'CONTEXT',_},{'APPLICATION',_}) -> true; 
	      ({'APPLICATION',_},{'UNIVERSAL',_}) -> true; 
	      ({A,T1},{A,T2}) when T1 =< T2 -> true; (_,_) -> false 
	   end,
    [T|_] = lists:sort(Pred,TagList),
    [T].

%% adds the textual order to the components to keep right order of
%% components in the asn1-value.
textual_order(Cs) ->
    Fun = fun(C=#'ComponentType'{},Index) ->
		  {C#'ComponentType'{textual_order=Index},Index+1};
	     (Other,Index) ->
		  {Other,Index}
	  end,
    {NewCs,_} = textual_order(Cs,Fun,1),
    NewCs.
textual_order(Cs,Fun,IxIn) when is_list(Cs) ->
    lists:mapfoldl(Fun,IxIn,Cs);
textual_order({Root,Ext},Fun,IxIn) ->
    {NewRoot,IxR} = textual_order(Root,Fun,IxIn),
    {NewExt,_} = textual_order(Ext,Fun,IxR),
    {{NewRoot,NewExt},dummy};
textual_order({Root1,Ext,Root2},Fun,IxIn) ->
    {NewRoot1,IxR} = textual_order(Root1,Fun,IxIn),
    {NewExt,IxE} = textual_order(Ext,Fun,IxR),
    {NewRoot2,_} = textual_order(Root2,Fun,IxE),
    {{NewRoot1,NewExt,NewRoot2},dummy}.

extension(Components) when is_list(Components) ->
    {Components,noext,[]};
extension({Root,ExtList}) ->
    ToOpt = fun(mandatory) ->
		    'OPTIONAL';
	       (X) -> X
	    end,
    {Root, [X#'ComponentType'{prop=ToOpt(Y)}||
	       X = #'ComponentType'{prop=Y}<-ExtList],[]};
extension({Root1,ExtList,Root2}) ->
    ToOpt = fun(mandatory) ->
		    'OPTIONAL';
	       (X) -> X
	    end,
    {Root1, [X#'ComponentType'{prop=ToOpt(Y)}||
		X = #'ComponentType'{prop=Y}<-ExtList], Root2}.

check_setof(S,Type,Component) when is_record(Component,type) ->
    simplify_type(check_type(S, Type, Component)).

check_selectiontype(S,Name,#type{def=Eref}) 
  when is_record(Eref,'Externaltypereference') ->
    {RefMod,TypeDef} = get_referenced_type(S,Eref),
    NewS = S#state{module=load_asn1_module(S,RefMod),
		   mname=RefMod,
		   tname=get_datastr_name(TypeDef)},
    check_selectiontype2(NewS,Name,TypeDef);
check_selectiontype(S,Name,Type=#type{def={pt,_,_}}) ->
    TName = case S#state.recordtopname of
		[] -> S#state.tname;
		N -> N
	    end,
    TDef = #typedef{name=TName,typespec=Type},
    check_selectiontype2(S,Name,TDef);
check_selectiontype(S, _Name, Type) ->
    asn1_error(S, {illegal_choice_type, error_value(Type)}).

check_selectiontype2(S,Name,TypeDef) ->
    NewS = S#state{recordtopname=get_datastr_name(TypeDef)},
    Components =
	try
	    CheckedType = check_type(NewS,TypeDef,TypeDef#typedef.typespec),
	    get_choice_components(S,CheckedType#type.def)
	catch error:_ ->
		asn1_error(S, {illegal_choice_type, error_value(TypeDef)})
	end,
    case lists:keyfind(Name, #'ComponentType'.name, Components) of
	#'ComponentType'{typespec=TS} -> TS;
	false -> asn1_error(S, {illegal_id, error_value(Name)})
    end.


get_choice_components(_S,{'CHOICE',Components}) when is_list(Components)->
    Components;
get_choice_components(_S,{'CHOICE',{C1,C2}}) when is_list(C1),is_list(C2) ->
    C1++C2;
get_choice_components(S,ERef=#'Externaltypereference'{}) ->
    {_RefMod,TypeDef}=get_referenced_type(S,ERef),
    #typedef{typespec=TS} = TypeDef,
    get_choice_components(S,TS#type.def).


	    
check_restrictedstring(_S,_Def,_Constr) ->
    ok.

check_objectidentifier(_S,_Constr) ->
    ok.

check_relative_oid(_S,_Constr) ->
    ok.
% check all aspects of a CHOICE
% - that all alternative names are unique
% - that all TAGS are ok (when TAG default is applied)
% - that each alternative is of a valid type
% - that the extension marks are valid
check_choice(S,Type,Components) when is_list(Components) ->
    Components1 = [C||C = #'ComponentType'{} <- Components],
    case check_unique(Components1,#'ComponentType'.name) of
	[] -> 
    %%    sort_canonical(Components),
	    Components2 = maybe_automatic_tags(S,Components),
	    NewComps = check_each_alternative2(S,Type,Components2),
	    %% ExtensionAdditionGroup markers i.e '[[' ']]' are not
	    %% significant for encoding/decoding a choice
	    %% therefore we remove them here
	    NewComps2 = lists:filter(fun(#'ExtensionAdditionGroup'{}) -> false;
					('ExtensionAdditionGroupEnd') -> false;
					(_) -> true
				     end,NewComps),
	    NewComps3 = simplify_comps(NewComps2),
	    check_unique_tags(S, NewComps3),
	    complist_as_tuple(NewComps3);
	Dupl ->
	    asn1_error(S, {duplicate_identifier,error_value(hd(Dupl))})
    end;
check_choice(_S,_,[]) -> 
    [].

maybe_automatic_tags(S,C) ->
    TagNos = tag_nums(C),
    case (S#state.module)#module.tagdefault of
	'AUTOMATIC' ->
	    generate_automatic_tags(S,C,TagNos);
	_ ->
	    %% maybe is the module a multi file module were only some of
	    %% the modules have defaulttag AUTOMATIC TAGS then the names
	    %% of those types are saved in the table automatic_tags
	    Name= S#state.tname,
	    case is_automatic_tagged_in_multi_file(Name) of
		true ->
		    generate_automatic_tags(S,C,TagNos);
		false ->
		    C
	    end
    end.

%% Pos == 1 for Root1, 2 for Ext, 3 for Root2
tag_nums(Cl) ->
    tag_nums(Cl,0,0).
tag_nums([#'EXTENSIONMARK'{}|Rest],Ext,Root2) ->
    tag_nums_ext(Rest,Ext,Root2);
tag_nums([_|Rest],Ext,Root2) ->
    tag_nums(Rest,Ext+1,Root2+1);
tag_nums([],Ext,Root2) ->
    [0,Ext,Root2].
tag_nums_ext([#'EXTENSIONMARK'{}|Rest],Ext,Root2) ->
    tag_nums_root2(Rest,Ext,Root2);
tag_nums_ext([_|Rest],Ext,Root2) ->
    tag_nums_ext(Rest,Ext,Root2);
tag_nums_ext([],Ext,_Root2) ->
    [0,Ext,0].
tag_nums_root2([_|Rest],Ext,Root2) ->
    tag_nums_root2(Rest,Ext+1,Root2);
tag_nums_root2([],Ext,Root2) ->
    [0,Ext,Root2].
    
is_automatic_tagged_in_multi_file(Name) ->
    case asn1ct_table:exists(automatic_tags) of
	false ->
	    %% this case when not multifile compilation
	    false;
	true ->
	    case asn1ct_table:lookup(automatic_tags, Name) of
		[] -> false;
		_ -> true
	    end
    end.

generate_automatic_tags(_S,C,TagNo) ->
    case any_manual_tag(C) of
	true ->
	    C;
	false ->
	    generate_automatic_tags1(C,TagNo)
    end.

generate_automatic_tags1([H|T],[TagNo|TagNos]) when is_record(H,'ComponentType') ->
    #'ComponentType'{typespec=Ts} = H,
    NewTs = Ts#type{tag=[#tag{class='CONTEXT',
			     number=TagNo,
			     type={default,'IMPLICIT'},
			     form= 0 }]}, % PRIMITIVE
    [H#'ComponentType'{typespec=NewTs}|generate_automatic_tags1(T,[TagNo+1|TagNos])];
generate_automatic_tags1([ExtMark = #'EXTENSIONMARK'{}|T],[_TagNo|TagNos]) -> 
    [ExtMark | generate_automatic_tags1(T,TagNos)];
generate_automatic_tags1([H|T],TagList) -> % ExtensionAdditionGroup etc are just ignored
    [H | generate_automatic_tags1(T,TagList)];
generate_automatic_tags1([],_) ->
    [].

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Returns true if there is at least one ComponentType with a manually 
%% specified tag. No manual tag is indicated by typespec=#type{tag=[]}
%% so we check if we find a tag =/= [] and return true in that case
%% all other things in the componentlist like (EXTENSIONMARK, 
%% ExtensionAdditionGroup,...) except ComponentType is simply
%% ignored/skipped
any_manual_tag([#'ComponentType'{typespec=#type{tag=Tag}}|_Rest]) 
  when Tag =/= []->
    true;
any_manual_tag([_|Rest]) ->
    any_manual_tag(Rest);
any_manual_tag([]) ->
    false.


check_unique_tags(S,C) ->
    case (S#state.module)#module.tagdefault of
	'AUTOMATIC' ->
	    case any_manual_tag(C) of
		false ->
		    true;
		true ->
		    check_unique_tags(S, C, [])
	    end;
	_ ->
	    check_unique_tags(S, C, [])
    end.

check_unique_tags(S, [#'ComponentType'{name=Name,tags=Tags0}|T], Acc) ->
    Tags = [{Tag,Name} || Tag <- Tags0],
    check_unique_tags(S, T, Tags ++ Acc);
check_unique_tags(S, [_|T], Acc) ->
    check_unique_tags(S, T, Acc);
check_unique_tags(S, [], Acc) ->
    R0 = sofs:relation(Acc),
    R1 = sofs:relation_to_family(R0),
    R2 = sofs:to_external(R1),
    Dup = [Els || {_,[_,_|_]=Els} <- R2],
    case Dup of
	[] ->
	    ok;
	[FirstDupl|_] ->
	    asn1_error(S, {duplicate_tags,FirstDupl})
    end.

check_unique(L,Pos) ->
    Slist = lists:keysort(Pos,L),
    check_unique2(Slist,Pos,[]).

check_unique2([A,B|T],Pos,Acc) when element(Pos,A) == element(Pos,B) ->
    check_unique2([B|T],Pos,[element(Pos,B)|Acc]);
check_unique2([_|T],Pos,Acc) ->
    check_unique2(T,Pos,Acc);
check_unique2([],_,Acc) ->
    lists:reverse(Acc).


%% Replaces check_each_component and does the same work except that
%% it keeps the complist as a flat list and does not create a tuple with root and
%% extensions separated
check_each_component2(S,Type,Components) ->
    check_each_component2(S,Type,Components,[]).

check_each_component2(S = #state{abscomppath=Path,recordtopname=TopName},
		     Type,
		     [C = #'ComponentType'{name=Cname,typespec=Ts,prop=Prop}|Ct],
		     Acc) ->
    NewAbsCPath = 
	case Ts#type.def of
	    #'Externaltypereference'{} -> [];
	    _ -> [Cname|Path]
	end,%%XXX Cname = 'per-message-indicators'
    CheckedTs = check_type(S#state{abscomppath=NewAbsCPath,
				   recordtopname=[Cname|TopName]},Type,Ts),
    NewTags = get_taglist(S,CheckedTs),

    NewProp =
	case normalize_value(S,CheckedTs,Prop,[Cname|TopName]) of
	    mandatory -> mandatory;
	    'OPTIONAL' -> 'OPTIONAL';
	    DefaultValue -> {'DEFAULT',DefaultValue}
	end,
    NewC = C#'ComponentType'{typespec=CheckedTs,prop=NewProp,tags=NewTags},
    check_each_component2(S,Type,Ct,[NewC|Acc]);

check_each_component2(S,Type,[OtherMarker|Ct],Acc) ->
    %% let 'EXTENSIONMARK' and 'ExtensionAdditionGroup' markers pass through as is
    check_each_component2(S,Type,Ct,[OtherMarker|Acc]);
check_each_component2(_S,_,[],Acc) ->
    lists:reverse(Acc).


%% check_each_alternative2(S,Type,{Rlist,ExtList}) ->
%%     {check_each_alternative(S,Type,Rlist),
%%      check_each_alternative(S,Type,ExtList)};
check_each_alternative2(S,Type,[C|Ct]) ->
    check_each_alternative2(S,Type,[C|Ct],[]).

check_each_alternative2(S=#state{abscomppath=Path,recordtopname=TopName},
		       Type,
		       [C = #'ComponentType'{name=Cname,typespec=Ts}|Ct],
		       Acc) ->
    NewAbsCPath = 
	case Ts#type.def of
	    #'Externaltypereference'{} -> [];
	    _ -> [Cname|Path]
	end,
    CheckedTs = check_type(S#state{abscomppath=NewAbsCPath,
				   recordtopname=[Cname|TopName]},Type,Ts),
    NewTags = get_taglist(S,CheckedTs),

    NewC = C#'ComponentType'{typespec=CheckedTs,tags=NewTags},
    check_each_alternative2(S,Type,Ct,[NewC|Acc]);
	    
check_each_alternative2(S,Type,[OtherMarker|Ct],Acc) ->
    %% let 'EXTENSIONMARK' and 'ExtensionAdditionGroup' markers pass through as is
    check_each_alternative2(S,Type,Ct,[OtherMarker|Acc]);
check_each_alternative2(_S,_,[],Acc) ->
    lists:reverse(Acc).


%% componentrelation_leadingattr/2 searches the structure for table
%% constraints, if any is found componentrelation_leadingattr/5 is
%% called.
componentrelation_leadingattr(S,CompList) ->

    %% get_simple_table_if_used/2 should find out whether there are any
    %% component relation constraints in the entire tree of Cs1 that
    %% relates to this level. It returns information about the simple
    %% table constraint necessary for the the call to
    %% componentrelation_leadingattr/6. The step when the leading
    %% attribute and the syntax tree is modified to support the code
    %% generating.
    case get_simple_table_if_used(S,CompList) of
	[] -> {false,CompList};
	_ ->
	    componentrelation_leadingattr(S,CompList,CompList,[],[])
    end.


%%FIXME expand_ExtAddGroups([C#'ExtensionAdditionGroup'{components=ExtAdds}|T],
%% 		    CurrPos,PosAcc,CompAcc) ->
%%     expand_ExtAddGroups(T,CurrPos+ L = lenght(ExtAdds),[{CurrPos,L}|PosAcc],ExtAdds++CompAcc);
%% expand_ExtAddGroups([C|T],CurrPos,PosAcc,CompAcc) ->
%%     expand_ExtAddGroups(T,CurrPos+ 1,PosAcc,[C|CompAcc]);
%% expand_ExtAddGroups([],_CurrPos,PosAcc,CompAcc) ->
%%     {lists:reverse(PosAcc),lists:reverse(CompAcc)}.


%% componentrelation_leadingattr/6 when all components are searched
%% the new modified components are returned together with the "leading
%% attribute" information, which later is stored in the tablecinf
%% field in the SEQUENCE/SET record. The "leading attribute"
%% information is used to generate the lookup in the object set
%% table. The other information gathered in the #type.tablecinf field
%% is used in code generating phase too, to recognice the proper
%% components for "open type" encoding and to propagate the result of
%% the object set lookup when needed.
componentrelation_leadingattr(_,[],_CompList,[],NewCompList) ->
    {false,lists:reverse(NewCompList)};
componentrelation_leadingattr(_,[],_CompList,LeadingAttr,NewCompList) ->
    {lists:last(LeadingAttr),lists:reverse(NewCompList)}; %send all info in Ts later
componentrelation_leadingattr(S,[C= #'ComponentType'{}|Cs],CompList,Acc,CompAcc) ->
    {LAAcc,NewC} =
	case catch componentrelation1(S,C#'ComponentType'.typespec,
				      [C#'ComponentType'.name]) of
	    {'EXIT',_} ->
		{[],C};
	    {CRI=[{_A1,_B1,_C1,_D1}|_Rest],NewTSpec} ->
		%% {ObjectSet,AtPath,ClassDef,Path}
		%% _A1 is a reference to the object set of the
		%% component relation constraint.
		%% _B1 is the path of names in the at-list of the
		%% component relation constraint.
		%% _C1 is the class definition of the
		%% ObjectClassFieldType.
		%% _D1 is the path of components that was traversed to
		%% find this constraint.
		case leading_attr_index(S,CompList,CRI,
					lists:reverse(S#state.abscomppath),[]) of
		    [] ->
			{[],C};
		    [{ObjSet,Attr,N,ClassDef,_Path,ValueIndex}|_NewRest] ->
			OS = object_set_mod_name(S,ObjSet),
			UniqFN = get_unique_fieldname(S,
						      #classdef{typespec=ClassDef}),
			%% Res should be done differently: even though
			%% a unique field name exists it is not
			%% certain that the ObjectClassFieldType of
			%% the simple table constraint picks that
			%% class field.
			Res = #simpletableattributes{objectsetname=OS,
						     c_name=Attr,
						     c_index=N,
						     usedclassfield=UniqFN,
						     uniqueclassfield=UniqFN,
						     valueindex=ValueIndex},
			{[Res],C#'ComponentType'{typespec=NewTSpec}}
		end;
	    _ ->
		%% no constraint was found
		{[],C}
	end,
    componentrelation_leadingattr(S,Cs,CompList,LAAcc++Acc,
				  [NewC|CompAcc]);
componentrelation_leadingattr(S,[NotComponentType|Cs],CompList,LeadingAttr,NewCompList) ->
    componentrelation_leadingattr(S,Cs,CompList,LeadingAttr,[NotComponentType|NewCompList]).


object_set_mod_name(_S,ObjSet) when is_atom(ObjSet) ->
    ObjSet;
object_set_mod_name(#state{mname=M},
		    #'Externaltypereference'{module=M,type=T}) ->
    {M,T};
object_set_mod_name(S,#'Externaltypereference'{module=M,type=T}) ->
    case lists:member(M,S#state.inputmodules) of
	true -> 
	    T;
	false ->
	    {M,T}
    end.


%% get_simple_table_if_used/2 searches the structure of Cs for any
%% component relation constraints due to the present level of the
%% structure. If there are any, the necessary information for code
%% generation of the look up functionality in the object set table are
%% returned.
get_simple_table_if_used(S,Cs) ->
    CNames = [Name||#'ComponentType'{name=Name}<-Cs],
    JustComponents = [C || C = #'ComponentType'{}<-Cs],
    RefedSimpleTable=any_component_relation(S,JustComponents,CNames,[],[]),
    get_simple_table_info(S,Cs,remove_doubles(RefedSimpleTable)).

remove_doubles(L) ->
    remove_doubles(L,[]).
remove_doubles([H|T],Acc) ->
    NewT = remove_doubles1(H,T),
    remove_doubles(NewT,[H|Acc]);
remove_doubles([],Acc) ->
    Acc.

remove_doubles1(El,L) ->
    case lists:delete(El,L) of
	L -> L;
	NewL -> remove_doubles1(El,NewL)
    end.

%% get_simple_table_info searches the components Cs by the path from
%% an at-list (third argument), and follows into a component of it if
%% necessary, to get information needed for code generating.
%%
%% Returns a list of tuples with three elements. It holds a list of
%% atoms that is the path, the name of the field of the class that are
%% referred to in the ObjectClassFieldType, and the name of the unique
%% field of the class of the ObjectClassFieldType. 
%%
% %% The level information outermost/innermost must be kept. There are
% %% at least two possibilities to cover here for an outermost case: 1)
% %% Both the simple table and the component relation have a common path
% %% at least one step below the outermost level, i.e. the leading
% %% information shall be on a sub level. 2) They don't have any common
% %% path.
get_simple_table_info(S, Cs, AtLists) ->
    [get_simple_table_info1(S, Cs, AtList, []) || AtList <- AtLists].

get_simple_table_info1(S, Cs, [Cname|Cnames], Path) ->
    #'ComponentType'{} = C =
	lists:keyfind(Cname, #'ComponentType'.name, Cs),
    get_simple_table_info2(S, C, Cnames, [Cname|Path]).

get_simple_table_info2(S, #'ComponentType'{name=Name,typespec=TS}, [], Path) ->
    OCFT = simple_table_get_ocft(S, Name, TS),
    case lists:keymember(simpletable, 1, TS#type.constraint) of
	true ->
	    simple_table_info(S, OCFT, Path);
	false ->
	    asn1_error(S, {missing_table_constraint,Name})
    end;
get_simple_table_info2(S, #'ComponentType'{typespec=TS}, Cnames, Path) ->
    Components = get_atlist_components(TS#type.def),
    get_simple_table_info1(S, Components, Cnames, Path).

simple_table_get_ocft(_, _, #type{def=#'ObjectClassFieldType'{}=OCFT}) ->
    OCFT;
simple_table_get_ocft(S, Component, #type{constraint=Constr}) ->
    case lists:keyfind(ocft, 1, Constr) of
	{ocft,OCFT} ->
	    OCFT;
	false ->
	    asn1_error(S, {missing_ocft,Component})
    end.

simple_table_info(S,#'ObjectClassFieldType'{classname=ClRef,
					    class=ObjectClass,
					  fieldname=FieldName},Path) ->

    ObjectClassFieldName =
	case FieldName of
	    {LastFieldName,[]} -> LastFieldName;
	    {_FirstFieldName,FieldNames} ->
		lists:last(FieldNames)
	end,
    %%ObjectClassFieldName is the last element in the dotted
    %%list of the ObjectClassFieldType. The last element may
    %%be of another class, that is referenced from the class
    %%of the ObjectClassFieldType
    ClassDef =
	case ObjectClass of
	    [] ->
		{_,CDef}=get_referenced_type(S,ClRef),
		CDef;
	    _ -> #classdef{typespec=ObjectClass}
	end,
    UniqueName = get_unique_fieldname(S, ClassDef),
    {lists:reverse(Path),ObjectClassFieldName,UniqueName}.

%% any_component_relation searches for all component relation
%% constraints that refers to the actual level and returns a list of
%% the "name path" in the at-list to the component relation constraint
%% that must refer to a simple table constraint. The list is empty if
%% no component relation constraints were found.
%% 
%% NamePath has the names of all components that are followed from the
%% beginning of the search. CNames holds the names of all components
%% of the start level, this info is used if an outermost at-notation
%% is found to check the validity of the at-list.
any_component_relation(S,[#'ComponentType'{name=CName,typespec=Type}|Cs],CNames,NamePath,Acc) ->
    CRelPath =
	case lists:keyfind(componentrelation, 1, Type#type.constraint) of
	    {_,_,AtNotation} ->
		%% Found component relation constraint, now check
		%% whether this constraint is relevant for the level
		%% where the search started
		AtNot = extract_at_notation(AtNotation),
		%% evaluate_atpath returns the relative path to the
		%% simple table constraint from where the component
		%% relation is found.
		evaluate_atpath(S,NamePath,CNames,AtNot);
	    false ->
		[]
	end,
    InnerAcc =
	case {Type#type.inlined,
	      asn1ct_gen:type(asn1ct_gen:get_inner(Type#type.def))} of
	    {no,{constructed,bif}} ->

		{InnerCs,NewNamePath} = 
		    case get_components(Type#type.def) of
			T when is_record(T,type) -> {T,NamePath};
			IC -> {IC,[CName|NamePath]}
		    end,
		%% here we are interested in components of an
		%% SEQUENCE/SET OF as well as SEQUENCE, SET and CHOICE
		any_component_relation(S,InnerCs,CNames,NewNamePath,[]);
	    _ ->
		[]
	end,
    any_component_relation(S,Cs,CNames,NamePath,InnerAcc++CRelPath++Acc);
any_component_relation(S,Type,CNames,NamePath,Acc) when is_record(Type,type) ->
    CRelPath =
	case lists:keyfind(componentrelation, 1, Type#type.constraint) of
	    {_,_,AtNotation} ->
		AtNot = extract_at_notation(AtNotation),
		evaluate_atpath(S,NamePath,CNames,AtNot);
	    false ->
		[]
	end,
    InnerAcc =
	case {Type#type.inlined,
	      asn1ct_gen:type(asn1ct_gen:get_inner(Type#type.def))} of
	    {no,{constructed,bif}} ->
		InnerCs = get_components(Type#type.def),
		any_component_relation(S,InnerCs,CNames,NamePath,[]);
	    _ ->
		[]
	end,
    InnerAcc  ++ CRelPath ++ Acc;
%% Just skip the markers for ExtensionAdditionGroup start and end
%% in this function
any_component_relation(S,[#'ExtensionAdditionGroup'{}|Cs],CNames,NamePath,Acc) ->
    any_component_relation(S,Cs,CNames,NamePath,Acc);
any_component_relation(S,['ExtensionAdditionGroupEnd'|Cs],CNames,NamePath,Acc) ->
    any_component_relation(S,Cs,CNames,NamePath,Acc);
any_component_relation(_,[],_,_,Acc) ->
    Acc.

%% evaluate_atpath/4 finds out whether the at notation refers to the
%% search level. The list of referenced names in the AtNot list shall
%% begin with a name that exists on the level it refers to. If the
%% found AtPath is refering to the same sub-branch as the simple table
%% has, then there shall not be any leading attribute info on this
%% level.
evaluate_atpath(_,[],Cnames,{innermost,AtPath=[Ref|_Refs]}) ->
    %% any innermost constraint found deeper in the structure is
    %% ignored.
    case lists:member(Ref,Cnames) of
	true -> [AtPath];
	false -> []
    end;
%% In this case must check that the AtPath doesn't step any step of
%% the NamePath, in that case the constraint will be handled in an
%% inner level.
evaluate_atpath(S=#state{abscomppath=TopPath},NamePath,Cnames,{outermost,AtPath=[_Ref|_Refs]}) ->
    AtPathBelowTop =
	case TopPath of
	    [] -> AtPath;
	    _ ->
		case lists:prefix(TopPath,AtPath) of
		    true ->
			lists:subtract(AtPath,TopPath);
		    _ -> []
		end
	end,
    case {NamePath,AtPathBelowTop} of
	{[H|_T1],[H|_T2]} -> []; % this must be handled in lower level
	{_,[]} -> [];% this must be handled in an above level
	{_,[H|_T]} ->
	    case lists:member(H,Cnames) of
		true -> [AtPathBelowTop];
		_ -> asn1_error(S, {invalid_at_path, AtPath})
	    end
    end;
evaluate_atpath(_,_,_,_) ->
    [].
    
%% Type may be any of SEQUENCE, SET, CHOICE, SEQUENCE OF, SET OF but
%% only the three first have valid components.
get_atlist_components(Def) ->
    get_components(atlist,Def).

get_components(Def) ->
    get_components(any,Def).

get_components(_,#'SEQUENCE'{components=Cs}) ->
    tuple2complist(Cs);
get_components(_,#'SET'{components=Cs}) ->
    tuple2complist(Cs);
get_components(_,{'CHOICE',Cs}) ->
    tuple2complist(Cs);
%do not step in inlined structures
get_components(any,{'SEQUENCE OF',T = #type{def=_Def,inlined=no}}) ->
%    get_components(any,Def);
    T;
get_components(any,{'SET OF',T = #type{def=_Def,inlined=no}}) ->
%    get_components(any,Def);
    T;
get_components(_,_) ->
    [].

tuple2complist({R,E}) ->
    R ++ E;
tuple2complist({R1,E,R2}) ->
    R1 ++ E ++ R2;
tuple2complist(List) when is_list(List) ->
    List.

extract_at_notation([{Level,ValueRefs}]) ->
    {Level,[Name || #'Externalvaluereference'{value=Name} <- ValueRefs]}.
    
%% componentrelation1/1 identifies all componentrelation constraints
%% that exist in C or in the substructure of C. Info about the found
%% constraints are returned in a list. It is ObjectSet, the reference
%% to the object set, AttrPath, the name atoms extracted from the
%% at-list in the component relation constraint, ClassDef, the
%% objectclass record of the class of the ObjectClassFieldType, Path,
%% that is the component name "path" from the searched level to this
%% constraint.
%%
%% The function is called with one component of the type in turn and
%% with the component name in Path at the first call. When called from
%% within, the name of the inner component is added to Path.
componentrelation1(S,C = #type{def=Def,constraint=Constraint,tablecinf=TCI},
		   Path) ->
    Ret =
%	case Constraint of
%	    [{componentrelation,{_,_,ObjectSet},AtList}|_Rest] ->
	case lists:keyfind(componentrelation, 1, Constraint) of
	    {_,{_,_,ObjectSet},AtList} ->
		[{_,AL=[#'Externalvaluereference'{}|_R1]}|_R2] = AtList,
		%% Note: if Path is longer than one,i.e. it is within
		%% an inner type of the actual level, then the only
		%% relevant at-list is of "outermost" type.
%%		#'ObjectClassFieldType'{class=ClassDef} = Def,
		ClassDef = get_ObjectClassFieldType_classdef(S,Def),
		AtPath = 
		    lists:map(fun(#'Externalvaluereference'{value=V})->V end,
			      AL),
		{[{ObjectSet,AtPath,ClassDef,Path}],Def};
	    false ->
		%% check the inner type of component
		innertype_comprel(S,Def,Path)
	end,
    case Ret of
	nofunobj ->
	    nofunobj; %% ignored by caller
	{CRelI=[{ObjSet,_,_,_}],NewDef} -> %%
	    TCItmp = lists:subtract(TCI,[{objfun,ObjSet}]),
	    {CRelI,C#type{tablecinf=[{objfun,ObjSet}|TCItmp],def=NewDef}};
	{CompRelInf,NewDef} -> %% more than one tuple in CompRelInf
	    TCItmp = lists:subtract(TCI,[{objfun,anyset}]),
	    {CompRelInf,C#type{tablecinf=[{objfun,anyset}|TCItmp],def=NewDef}}
    end.

innertype_comprel(S,{'SEQUENCE OF',Type},Path) ->
    case innertype_comprel1(S,Type,Path) of
	nofunobj ->
	    nofunobj;
	{CompRelInf,NewType} ->
	    {CompRelInf,{'SEQUENCE OF',NewType}}
    end;
innertype_comprel(S,{'SET OF',Type},Path) ->
    case innertype_comprel1(S,Type,Path) of
	nofunobj ->
	    nofunobj;
	{CompRelInf,NewType} ->
	    {CompRelInf,{'SET OF',NewType}}
    end;
innertype_comprel(S,{'CHOICE',CTypeList},Path) ->
    case componentlist_comprel(S,CTypeList,[],Path,[]) of
	nofunobj ->
	    nofunobj;
	{CompRelInf,NewCs} ->
	    {CompRelInf,{'CHOICE',NewCs}}
    end;
innertype_comprel(S,Seq = #'SEQUENCE'{components=Cs},Path) ->
    case componentlist_comprel(S,Cs,[],Path,[]) of
	nofunobj ->
	    nofunobj;
	{CompRelInf,NewCs} ->
	    {CompRelInf,Seq#'SEQUENCE'{components=NewCs}}
    end;
innertype_comprel(S,Set = #'SET'{components=Cs},Path) ->
    case componentlist_comprel(S,Cs,[],Path,[]) of
	nofunobj ->
	    nofunobj;
	{CompRelInf,NewCs} ->
	    {CompRelInf,Set#'SET'{components=NewCs}}
    end;
innertype_comprel(_,_,_) ->
    nofunobj.

componentlist_comprel(S,[C = #'ComponentType'{name=Name,typespec=Type}|Cs],
		      Acc,Path,NewCL) ->
    case catch componentrelation1(S,Type,Path++[Name]) of
	{'EXIT',_} ->
	    componentlist_comprel(S,Cs,Acc,Path,[C|NewCL]);
	nofunobj ->
	    componentlist_comprel(S,Cs,Acc,Path,[C|NewCL]);
	{CRelInf,NewType} ->
	    componentlist_comprel(S,Cs,CRelInf++Acc,Path,
				  [C#'ComponentType'{typespec=NewType}|NewCL])
    end;
componentlist_comprel(_,[],Acc,_,NewCL) ->
    case Acc of
	[] ->
	    nofunobj;
	_ ->
	    {Acc,lists:reverse(NewCL)}
    end.

innertype_comprel1(S,T = #type{def=Def,constraint=Cons,tablecinf=TCI},Path) ->
    Ret =
	case lists:keyfind(componentrelation, 1, Cons) of
	    {_,{_,_,ObjectSet},AtList} ->
		%% This AtList must have an "outermost" at sign to be
		%% relevent here.
		[{_,AL=[#'Externalvaluereference'{value=_Attr}|_R1]}|_R2] 
		    = AtList,
%%		#'ObjectClassFieldType'{class=ClassDef} = Def,
		ClassDef = get_ObjectClassFieldType_classdef(S,Def),
		AtPath = 
		    lists:map(fun(#'Externalvaluereference'{value=V})->V end,
			      AL),
		[{ObjectSet,AtPath,ClassDef,Path}];
	    false ->
		innertype_comprel(S,Def,Path)
	end,
    case Ret of
	nofunobj -> nofunobj;
	L = [{ObjSet,_,_,_}] ->
	    TCItmp = lists:subtract(TCI,[{objfun,ObjSet}]),
	    {L,T#type{tablecinf=[{objfun,ObjSet}|TCItmp]}};
	{CRelInf,NewDef} ->
	    TCItmp = lists:subtract(TCI,[{objfun,anyset}]),
	    {CRelInf,T#type{def=NewDef,tablecinf=[{objfun,anyset}|TCItmp]}}
    end.


%% leading_attr_index counts the index and picks the name of the
%% component that is at the actual level in the at-list of the
%% component relation constraint (AttrP).  AbsP is the path of
%% component names from the top type level to the actual level. AttrP
%% is a list with the atoms from the at-list.
leading_attr_index(S,Cs,[H={_,AttrP,_,_}|T],AbsP,Acc) ->
    AttrInfo = 
	case lists:prefix(AbsP,AttrP) of
	    %% why this ?? It is necessary when in same situation as
	    %% TConstrChoice, there is an inner structure with an
	    %% outermost at-list and the "leading attribute" code gen
	    %% may be at a level some steps below the outermost level.
	    true ->
		RelativAttrP = lists:subtract(AttrP,AbsP),
		%% The header is used to calculate the index of the
		%% component and to give the fun, received from the
		%% object set look up, an unique name. The tail is
		%% used to match the proper value input to the fun.
		{hd(RelativAttrP),tl(RelativAttrP)};
	    false ->
		{hd(AttrP),tl(AttrP)}
	end,
    case leading_attr_index1(S,Cs,H,AttrInfo,1) of
	0 ->
	    leading_attr_index(S,Cs,T,AbsP,Acc);
	Res ->
	    leading_attr_index(S,Cs,T,AbsP,[Res|Acc])
    end;
leading_attr_index(_,_Cs,[],_,Acc) ->
    lists:reverse(Acc).

leading_attr_index1(_,[],_,_,_) ->
    0;
leading_attr_index1(S,[C|Cs],Arg={ObjectSet,_,CDef,P},
		    AttrInfo={Attr,SubAttr},N) ->
    case C#'ComponentType'.name of
	Attr ->
	    ValueMatch = value_match(S,C,Attr,SubAttr),
	    {ObjectSet,Attr,N,CDef,P,ValueMatch};
	_ ->
	    leading_attr_index1(S,Cs,Arg,AttrInfo,N+1)
    end.

%% value_math gathers information for a proper value match in the
%% generated encode function. For a SEQUENCE or a SET the index of the
%% component is counted. For a CHOICE the index is 2.
value_match(S,C,Name,SubAttr) ->
    value_match(S,C,Name,SubAttr,[]). % C has name Name
value_match(_S,#'ComponentType'{},_Name,[],Acc) ->
    Acc;% do not reverse, indexes in reverse order
value_match(S,#'ComponentType'{typespec=Type},Name,[At|Ats],Acc) ->
    InnerType = asn1ct_gen:get_inner(Type#type.def),
    Components =
	case get_atlist_components(Type#type.def) of
	    [] -> asn1_error(S, {invalid_element, Name});
	    Comps -> Comps
	end,
    {Index,ValueIndex} = component_value_index(S,InnerType,At,Components),
    value_match(S,lists:nth(Index,Components),At,Ats,[ValueIndex|Acc]).

component_value_index(S,'CHOICE',At,Components) ->
    {component_index(S,At,Components),2};
component_value_index(S,_,At,Components) ->
    %% SEQUENCE or SET
    Index = component_index(S,At,Components),
    {Index,{Index+1,At}}.

component_index(S,Name,Components) ->
    component_index1(S,Name,Components,1).
component_index1(_S,Name,[#'ComponentType'{name=Name}|_Cs],N) ->
    N;
component_index1(S,Name,[_C|Cs],N) ->
    component_index1(S,Name,Cs,N+1);
component_index1(S,Name,[],_) ->
    asn1_error(S, {invalid_at_list, Name}).

get_unique_fieldname(S, #classdef{typespec=TS}) ->
    Fields = TS#objectclass.fields,
    get_unique_fieldname1(S, Fields, []);
get_unique_fieldname(S,#typedef{typespec=#type{def=ClassRef}}) ->
    %% A class definition may be referenced as
    %% REFED-CLASS ::= DEFINED-CLASS and then REFED-CLASS is a typedef
    {_M,ClassDef} = get_referenced_type(S,ClassRef),
    get_unique_fieldname(S,ClassDef).

get_unique_fieldname1(S, [{fixedtypevaluefield,Name,_,'UNIQUE',Opt}|T], Acc) ->
    get_unique_fieldname1(S, T, [{Name,Opt}|Acc]);
get_unique_fieldname1(S, [_|T], Acc) ->
    get_unique_fieldname1(S, T, Acc);
get_unique_fieldname1(S, [], Acc) ->
    case Acc of
	[] -> no_unique;
	[Name] -> Name;
	[_|_] -> asn1_error(S, multiple_uniqs)
    end.

get_tableconstraint_info(S,Type,{CheckedTs,EComps,CheckedTs2}) ->
    {get_tableconstraint_info(S,Type,CheckedTs,[]),
     get_tableconstraint_info(S,Type,EComps,[]),
     get_tableconstraint_info(S,Type,CheckedTs2,[])};
get_tableconstraint_info(S,Type,{CheckedTs,EComps}) ->
    {get_tableconstraint_info(S,Type,CheckedTs,[]),
     get_tableconstraint_info(S,Type,EComps,[])};
get_tableconstraint_info(S,Type,CheckedTs) ->
    get_tableconstraint_info(S,Type,CheckedTs,[]).

get_tableconstraint_info(_S,_Type,[],Acc) ->
    lists:reverse(Acc);
get_tableconstraint_info(S,Type,[C=#'ComponentType'{typespec=CheckedTs}|Cs],Acc) ->
    AccComp = 
	case CheckedTs#type.def of 
	    %% ObjectClassFieldType
	    OCFT=#'ObjectClassFieldType'{} ->
		NewOCFT =
		    OCFT#'ObjectClassFieldType'{class=[]},
		C#'ComponentType'{typespec=
				  CheckedTs#type{
				    def=NewOCFT
				    }};
%				    constraint=[{tableconstraint_info,
%						 FieldRef}]}};
	    {'SEQUENCE OF',SOType} when is_record(SOType,type),
					(element(1,SOType#type.def)=='CHOICE') ->
		CTypeList = element(2,SOType#type.def),
		NewInnerCList = 
		    get_tableconstraint_info(S,Type,CTypeList),
		C#'ComponentType'{typespec=
				  CheckedTs#type{
				    def={'SEQUENCE OF',
					 SOType#type{def={'CHOICE',
							  NewInnerCList}}}}};
	    {'SET OF',SOType} when is_record(SOType,type),
				   (element(1,SOType#type.def)=='CHOICE') ->
		CTypeList = element(2,SOType#type.def),
		NewInnerCList = 
		    get_tableconstraint_info(S,Type,CTypeList),
		C#'ComponentType'{typespec=
				  CheckedTs#type{
				    def={'SET OF',
					 SOType#type{def={'CHOICE',
							  NewInnerCList}}}}};
	    _ ->
		C
	end,
    get_tableconstraint_info(S,Type,Cs,[AccComp|Acc]);
get_tableconstraint_info(S,Type,[C|Cs],Acc) ->
    get_tableconstraint_info(S,Type,Cs,[C|Acc]).

get_referenced_fieldname([{_,FirstFieldname}]) ->
    {FirstFieldname,[]};
get_referenced_fieldname([{_,FirstFieldname}|T]) ->
    {FirstFieldname,[element(2, X) || X <- T]}.

%% get_ObjectClassFieldType_classdef gets the def of the class of the
%% ObjectClassFieldType, i.e. the objectclass record. If the type has
%% been checked (it may be a field type of an internal SEQUENCE) the
%% class field = [], then the classdef has to be fetched by help of
%% the class reference in the classname field.
get_ObjectClassFieldType_classdef(S,#'ObjectClassFieldType'{classname=Name,class=[]}) ->
    {_,#classdef{typespec=TS}} = get_referenced_type(S,Name),
    TS;
get_ObjectClassFieldType_classdef(_,#'ObjectClassFieldType'{class=Cl}) ->
    Cl.

get_OCFType(S,Fields,FieldnameList=[{_FieldType,_PrimFieldName}|_]) ->
    get_OCFType(S,Fields,[PFN||{_,PFN} <- FieldnameList]);
get_OCFType(S,Fields,[PrimFieldName|Rest]) ->
    case lists:keysearch(PrimFieldName,2,Fields) of
	{value,{fixedtypevaluefield,_,Type,_Unique,_OptSpec}} ->
	    {fixedtypevaluefield,PrimFieldName,Type};
	{value,{objectfield,_,ClassRef,_Unique,_OptSpec}} ->
	    {MName,ClassDef} = get_referenced_type(S,ClassRef),
	    NewS = update_state(S#state{tname=get_datastr_name(ClassDef)},
				MName),
	    CheckedCDef = check_class(NewS,ClassDef),
	    get_OCFType(S,CheckedCDef#objectclass.fields,Rest);
	{value,{objectsetfield,_,Type,_OptSpec}} ->
	    {MName,ClassDef} = get_referenced_type(S,Type#type.def),
	    NewS = update_state(S#state{tname=get_datastr_name(ClassDef)},
				MName),
	    CheckedCDef = check_class(NewS,ClassDef),
	    get_OCFType(S,CheckedCDef#objectclass.fields,Rest);

	{value,Other} ->
	    {element(1,Other),PrimFieldName};
	_  ->
	    asn1_error(S, {illegal_object_field, PrimFieldName})
    end.

get_taglist(S,Ext) when is_record(Ext,'Externaltypereference') ->
    {_,T} = get_referenced_type(S,Ext),
    get_taglist(S,T#typedef.typespec);
get_taglist(S,Type) when is_record(Type,type) ->
    case Type#type.tag of
	[] ->
	    get_taglist(S,Type#type.def);
	[Tag|_]  ->
	    [asn1ct_gen:def_to_tag(Tag)]
    end;
get_taglist(S,{'CHOICE',{Rc,Ec}}) ->
    get_taglist1(S,Rc ++ Ec);
get_taglist(S,{'CHOICE',{R1,E,R2}}) ->
    get_taglist1(S,R1 ++ E ++ R2);
get_taglist(S,{'CHOICE',Components}) ->
    get_taglist1(S,Components);
%% ObjectClassFieldType OTP-4390
get_taglist(_S,#'ObjectClassFieldType'{type={typefield,_}}) ->
    [];
get_taglist(S,#'ObjectClassFieldType'{type={fixedtypevaluefield,_,Type}}) ->
    get_taglist(S,Type);
get_taglist(_, _) ->
    [].

get_taglist1(S,[#'ComponentType'{name=_Cname,tags=TagL}|Rest]) when is_list(TagL) -> 
    %% tag_list has been here , just return TagL and continue with next alternative
    TagL ++ get_taglist1(S,Rest);
get_taglist1(S,[#'ComponentType'{typespec=Ts,tags=undefined}|Rest]) ->
    get_taglist(S,Ts) ++ get_taglist1(S,Rest);
get_taglist1(S,[_H|Rest]) -> % skip EXTENSIONMARK
    get_taglist1(S,Rest);
get_taglist1(_S,[]) ->
    [].

%% def_to_tag(S,Def) ->
%%     case asn1ct_gen:def_to_tag(Def) of
%% 	{'UNIVERSAL',T} ->
%% 	    case asn1ct_gen:prim_bif(T) of
%% 		true ->
%% 		    ?TAG_PRIMITIVE(tag_number(T));
%% 		_ ->
%% 		    ?TAG_CONSTRUCTED(tag_number(T))
%% 	    end;
%% 	_ -> []
%%     end.
%% tag_number('BOOLEAN') -> 1;
%% tag_number('INTEGER') -> 2;
%% tag_number('BIT STRING') -> 3;
%% tag_number('OCTET STRING') -> 4;
%% tag_number('NULL') -> 5;
%% tag_number('OBJECT IDENTIFIER') -> 6;
%% tag_number('ObjectDescriptor') -> 7;
%% tag_number('EXTERNAL') -> 8;
%% tag_number('INSTANCE OF') -> 8;
%% tag_number('REAL') -> 9;
%% tag_number('ENUMERATED') -> 10;
%% tag_number('EMBEDDED PDV') -> 11;
%% tag_number('UTF8String') -> 12;
%% %%tag_number('RELATIVE-OID') -> 13;
%% tag_number('SEQUENCE') -> 16;
%% tag_number('SEQUENCE OF') -> 16;
%% tag_number('SET') -> 17;
%% tag_number('SET OF') -> 17;
%% tag_number('NumericString') -> 18;
%% tag_number('PrintableString') -> 19;
%% tag_number('TeletexString') -> 20;
%% %%tag_number('T61String') -> 20;
%% tag_number('VideotexString') -> 21;
%% tag_number('IA5String') -> 22;
%% tag_number('UTCTime') -> 23;
%% tag_number('GeneralizedTime') -> 24;
%% tag_number('GraphicString') -> 25;
%% tag_number('VisibleString') -> 26;
%% %%tag_number('ISO646String') -> 26;
%% tag_number('GeneralString') -> 27;
%% tag_number('UniversalString') -> 28;
%% tag_number('CHARACTER STRING') -> 29;
%% tag_number('BMPString') -> 30.

merge_tags(T1, T2) when is_list(T2) ->
    merge_tags2(T1 ++ T2, []);
merge_tags(T1, T2) ->
    merge_tags2(T1 ++ [T2], []).

merge_tags2([T1= #tag{type='IMPLICIT'}, T2 |Rest], Acc) ->
    merge_tags2([T1#tag{type=T2#tag.type, form=T2#tag.form}|Rest],Acc);
merge_tags2([T1= #tag{type={default,'IMPLICIT'}}, T2 |Rest], Acc) ->
    merge_tags2([T1#tag{type=T2#tag.type, form=T2#tag.form}|Rest],Acc);
merge_tags2([T1= #tag{type={default,'AUTOMATIC'}}, T2 |Rest], Acc) ->
    merge_tags2([T1#tag{type=T2#tag.type, form=T2#tag.form}|Rest],Acc);
merge_tags2([H|T],Acc) ->
    merge_tags2(T, [H|Acc]);
merge_tags2([], Acc) ->
    lists:reverse(Acc).

storeindb(S0, #module{name=ModName,typeorval=TVlist0}=M) ->
    S = S0#state{mname=ModName},
    TVlist1 = [{asn1ct:get_name_of_def(Def),Def} || Def <- TVlist0],
    case check_duplicate_defs(S, TVlist1) of
	ok ->
	    storeindb_1(S, M, TVlist0, TVlist1);
	{error,_}=Error ->
	    Error
    end.

storeindb_1(S, #module{name=ModName}=M, TVlist0, TVlist) ->
    NewM = M#module{typeorval=findtypes_and_values(TVlist0)},
    Maps = lists:member(maps, S#state.options),
    asn1_db:dbnew(ModName, S#state.erule, Maps),
    asn1_db:dbput(ModName, 'MODULE',  NewM),
    asn1_db:dbput(ModName, TVlist),
    include_default_class(S, NewM#module.name),
    include_default_type(NewM#module.name),
    ok.

check_duplicate_defs(S, Defs) ->
    Set0 = sofs:relation(Defs),
    Set1 = sofs:relation_to_family(Set0),
    Set = sofs:to_external(Set1),
    case [duplicate_def(S, N, Dup) || {N,[_,_|_]=Dup} <- Set] of
	[] ->
	    ok;
	[_|_]=E ->
	    {error,lists:append(E)}
    end.

duplicate_def(S, Name, Dups0) ->
    Dups1 = [{asn1ct:get_pos_of_def(Def),Def} || Def <- Dups0],
    [{Prev,_}|Dups] = lists:sort(Dups1),
    duplicate_def_1(S, Dups, Name, Prev).

duplicate_def_1(S, [{_,Def}|T], Name, Prev) ->
    E = return_asn1_error(S, Def, {already_defined,Name,Prev}),
    [E|duplicate_def_1(S, T, Name, Prev)];
duplicate_def_1(_, [], _, _) ->
    [].

findtypes_and_values(TVList) ->
    findtypes_and_values(TVList,[],[],[],[],[],[]).%% Types,Values,
%% Parameterizedtypes,Classes,Objects and ObjectSets

findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,typedef),is_record(H#typedef.typespec,'Object') ->
    findtypes_and_values(T,Tacc,Vacc,Pacc,Cacc,[H#typedef.name|Oacc],OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,typedef),is_record(H#typedef.typespec,'ObjectSet') ->
    findtypes_and_values(T,Tacc,Vacc,Pacc,Cacc,Oacc,[H#typedef.name|OSacc]);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,typedef) ->
    findtypes_and_values(T,[H#typedef.name|Tacc],Vacc,Pacc,Cacc,Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,valuedef) ->
    findtypes_and_values(T,Tacc,[H#valuedef.name|Vacc],Pacc,Cacc,Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,ptypedef) ->
    findtypes_and_values(T,Tacc,Vacc,[H#ptypedef.name|Pacc],Cacc,Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) 
  when is_record(H,classdef) ->
    findtypes_and_values(T,Tacc,Vacc,Pacc,[H#classdef.name|Cacc],Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc)
  when is_record(H,pvaluedef) ->
    findtypes_and_values(T,Tacc,[H#pvaluedef.name|Vacc],Pacc,Cacc,Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc)
  when is_record(H,pvaluesetdef) ->
    findtypes_and_values(T,Tacc,[H#pvaluesetdef.name|Vacc],Pacc,Cacc,Oacc,OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc)
  when is_record(H,pobjectdef) ->
    findtypes_and_values(T,Tacc,Vacc,Pacc,Cacc,[H#pobjectdef.name|Oacc],OSacc);
findtypes_and_values([H|T],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc)
  when is_record(H,pobjectsetdef) ->
    findtypes_and_values(T,Tacc,Vacc,Pacc,Cacc,Oacc,[H#pobjectsetdef.name|OSacc]);
findtypes_and_values([],Tacc,Vacc,Pacc,Cacc,Oacc,OSacc) ->
    {lists:reverse(Tacc),lists:reverse(Vacc),lists:reverse(Pacc),
     lists:reverse(Cacc),lists:reverse(Oacc),lists:reverse(OSacc)}.
    
return_asn1_error(#state{error_context=Context}=S, Error) ->
    return_asn1_error(S, Context, Error).

return_asn1_error(#state{mname=Where}, Item, Error) ->
    Pos = asn1ct:get_pos_of_def(Item),
    {structured_error,{Where,Pos},?MODULE,Error}.

-spec asn1_error(_, _) -> no_return().
asn1_error(S, Error) ->
    throw({error,return_asn1_error(S, Error)}).

format_error({already_defined,Name,PrevLine}) ->
    io_lib:format("the name ~p has already been defined at line ~p",
		  [Name,PrevLine]);
format_error({duplicate_identifier,Ids}) ->
    io_lib:format("the identifier '~p' has already been used", [Ids]);
format_error({duplicate_tags,Elements}) ->
    io_lib:format("duplicate tags in the elements: ~s",
		  [format_elements(Elements)]);
format_error({enum_illegal_redefinition,Id}) ->
    io_lib:format("'~s' must not be redefined", [Id]);
format_error({enum_not_ascending,Id,N,Prev}) ->
    io_lib:format("the values for enumerations which follow '...' must "
		  "be in ascending order, but '~p(~p)' is less than the "
		  "previous value '~p'", [Id,N,Prev]);
format_error({enum_reused_value,Id,Val}) ->
    io_lib:format("'~s' has the value '~p' which is used more than once",
		  [Id,Val]);
format_error({illegal_id, Id}) ->
    io_lib:format("illegal identifier: ~p", [Id]);
format_error({illegal_choice_type, Ref}) ->
    io_lib:format("expecting a CHOICE type: ~p", [Ref]);
format_error({illegal_class_name,Class}) ->
    io_lib:format("the class name '~s' is illegal (it must start with an uppercase letter and only contain uppercase letters, digits, or hyphens)", [Class]);
format_error({illegal_COMPONENTS_OF, Ref}) ->
    io_lib:format("expected a SEQUENCE or SET got: ~p", [Ref]);
format_error(illegal_external_value) ->
    "illegal value in EXTERNAL type";
format_error({illegal_instance_of,Class}) ->
    io_lib:format("using INSTANCE OF on class '~s' is illegal, "
		  "because INSTANCE OF may only be used on the class TYPE-IDENTIFIER",
		  [Class]);
format_error(illegal_integer_value) ->
    "expecting an integer value";
format_error(illegal_object) ->
    "expecting an object";
format_error({illegal_object_field, Id}) ->
    io_lib:format("expecting a class field: ~p",[Id]);
format_error({illegal_oid,o_id}) ->
    "illegal OBJECT IDENTIFIER";
format_error({illegal_oid,rel_oid}) ->
    "illegal RELATIVE-OID";
format_error(illegal_octet_string_value) ->
    "expecting a bstring or an hstring as value for an OCTET STRING";
format_error({illegal_typereference,Name}) ->
    io_lib:format("'~p' is used as a typereference, but does not start with an uppercase letter", [Name]);
format_error(illegal_table_constraint) ->
    "table constraints may only be applied to CLASS.&field constructs";
format_error(illegal_value) ->
    "expecting a value";
format_error({illegal_value, TYPE}) ->
    io_lib:format("expecting a ~s value", [TYPE]);
format_error({invalid_fields,Fields,Obj}) ->
    io_lib:format("invalid ~s in ~p", [format_fields(Fields),Obj]);
format_error({invalid_bit_number,Bit}) ->
    io_lib:format("the bit number '~p' is invalid", [Bit]);
format_error(invalid_table_constraint) ->
    "the table constraint is not an object set";
format_error(invalid_objectset) ->
    "expecting an object set";
format_error({implicit_tag_before,Kind}) ->
    "illegal implicit tag before " ++
	case Kind of
	    choice -> "'CHOICE'";
	    open_type -> "open type"
	end;
format_error({missing_mandatory_fields,Fields,Obj}) ->
    io_lib:format("missing mandatory ~s in ~p",
		  [format_fields(Fields),Obj]);
format_error({missing_table_constraint,Component}) ->
    io_lib:format("the component '~s' is referenced by a component relation constraint using the '@field-name' notation, but does not have a table constraint",
		  [Component]);
format_error({missing_id,Id}) ->
    io_lib:format("expected the mandatory component '~p'", [Id]);
format_error({missing_ocft,Component}) ->
    io_lib:format("the component '~s' must be an ObjectClassFieldType (CLASSNAME.&field-name)", [Component]);
format_error(multiple_uniqs) ->
    "implementation limitation: only one UNIQUE field is allowed in CLASS";
format_error({namelist_redefinition,Name}) ->
    io_lib:format("the name '~s' can not be redefined", [Name]);
format_error({param_bad_type, Ref}) ->
    io_lib:format("'~p' is not a parameterized type", [Ref]);
format_error(param_wrong_number_of_arguments) ->
    "wrong number of arguments";
format_error(reversed_range) ->
    "ranges must be given in increasing order";
format_error({syntax_duplicated_fields,Fields}) ->
    io_lib:format("~s must only occur once in the syntax list",
		  [format_fields(Fields)]);
format_error(syntax_nomatch) ->
    "unexpected end of object definition";
format_error({syntax_mandatory_in_optional_group,Name}) ->
    io_lib:format("the field '&~s' must not be within an optional group since it is not optional",
		  [Name]);
format_error({syntax_missing_mandatory_fields,Fields}) ->
    io_lib:format("missing mandatory ~s in the syntax list",
		  [format_fields(Fields)]);
format_error({syntax_nomatch,Actual}) ->
    io_lib:format("~s is not the next item allowed according to the defined syntax",
		  [Actual]);
format_error({syntax_undefined_field,Field}) ->
    io_lib:format("'&~s' is not a field of the class being defined",
		  [Field]);
format_error({undefined,Name}) ->
    io_lib:format("'~s' is referenced, but is not defined", [Name]);
format_error({undefined_export,Ref}) ->
    io_lib:format("'~s' is exported but is not defined", [Ref]);
format_error({undefined_field,FieldName}) ->
    io_lib:format("the field '&~s' is undefined", [FieldName]);
format_error({undefined_import,Ref,Module}) ->
    io_lib:format("'~s' is not exported from ~s", [Ref,Module]);
format_error({unique_and_default,Field}) ->
    io_lib:format("the field '&~s' must not have both 'UNIQUE' and 'DEFAULT'",
		  [Field]);
format_error({value_reused,Val}) ->
    io_lib:format("the value '~p' is used more than once", [Val]);
format_error({non_unique_object,Id}) ->
    io_lib:format("object set with a UNIQUE field value of '~p' is used more than once", [Id]);
format_error(Other) ->
    io_lib:format("~p", [Other]).

format_fields([F]) ->
    io_lib:format("field '&~s'", [F]);
format_fields([H|T]) ->
    [io_lib:format("fields '&~s'", [H])|
     [io_lib:format(", '&~s'", [F]) || F <- T]].

format_elements([H1,H2|T]) ->
    [io_lib:format("~p, ", [H1])|format_elements([H2|T])];
format_elements([H]) ->
    io_lib:format("~p", [H]).

include_default_type(Module) ->
    NameAbsList = default_type_list(),
    include_default_type1(Module,NameAbsList).

include_default_type1(_,[]) ->
    ok;
include_default_type1(Module,[{Name,TS}|Rest]) ->
    case asn1_db:dbget(Module,Name) of
	undefined ->
	    T = #typedef{name=Name,
			 typespec=TS},
		asn1_db:dbput(Module,Name,T);
	_ -> ok
    end,
    include_default_type1(Module,Rest).

default_type_list() ->
    %% The EXTERNAL type is represented, according to ASN.1 1997, 
    %% as a SEQUENCE with components: identification, data-value-descriptor
    %% and data-value.
    Syntax = 
	#'ComponentType'{name=syntax,
			 typespec=#type{def='OBJECT IDENTIFIER'},
			 prop=mandatory},
    Presentation_Cid =
	#'ComponentType'{name='presentation-context-id',
			 typespec=#type{def='INTEGER'},
			 prop=mandatory},
    Transfer_syntax =
	#'ComponentType'{name='transfer-syntax',
			 typespec=#type{def='OBJECT IDENTIFIER'},
			 prop=mandatory},
    Negotiation_items = 
	#type{def=
	      #'SEQUENCE'{components=
			  [Presentation_Cid,
			   Transfer_syntax#'ComponentType'{prop=mandatory}]}},
    Context_negot = 
	#'ComponentType'{name='context-negotiation',
			 typespec=Negotiation_items,
			 prop=mandatory},

    Data_value_descriptor =
	#'ComponentType'{name='data-value-descriptor',
			 typespec=#type{def='ObjectDescriptor'},
			 prop='OPTIONAL'},
    Data_value =
	#'ComponentType'{name='data-value',
			 typespec=#type{def='OCTET STRING'},
			 prop=mandatory},

    %% The EXTERNAL type is represented, according to ASN.1 1990, 
    %% as a SEQUENCE with components: direct-reference, indirect-reference,
    %% data-value-descriptor and encoding.

    Direct_reference = 
	#'ComponentType'{name='direct-reference',
			 typespec=#type{def='OBJECT IDENTIFIER'},
			 prop='OPTIONAL',
			 tags=[{'UNIVERSAL',6}]},

    Indirect_reference = 
	#'ComponentType'{name='indirect-reference',
			 typespec=#type{def='INTEGER'},
			 prop='OPTIONAL',
			 tags=[{'UNIVERSAL',2}]},

    Single_ASN1_type =
	#'ComponentType'{name='single-ASN1-type',
			 typespec=#type{tag=[{tag,'CONTEXT',0,
					      'EXPLICIT',32}],
					def='ANY'},
			 prop=mandatory,
			 tags=[{'CONTEXT',0}]},

    Octet_aligned =
	#'ComponentType'{name='octet-aligned',
			 typespec=#type{tag=[{tag,'CONTEXT',1,
					      'IMPLICIT',0}],
					def='OCTET STRING'},
			 prop=mandatory,
			 tags=[{'CONTEXT',1}]},

    Arbitrary =
	#'ComponentType'{name=arbitrary,
			 typespec=#type{tag=[{tag,'CONTEXT',2,
					      'IMPLICIT',0}],
					def={'BIT STRING',[]}},
			 prop=mandatory,
			 tags=[{'CONTEXT',2}]},

    Encoding =
	#'ComponentType'{name=encoding,
			 typespec=#type{def={'CHOICE',
					     [Single_ASN1_type,Octet_aligned,
					      Arbitrary]}},
			 prop=mandatory},

    EXTERNAL_components1990 =
	[Direct_reference,Indirect_reference,Data_value_descriptor,Encoding],
    
    %% The EMBEDDED PDV type is represented by a SEQUENCE type
    %% with components: identification and data-value
    Abstract = 
	#'ComponentType'{name=abstract,
			 typespec=#type{def='OBJECT IDENTIFIER'},
			 prop=mandatory},
    Transfer =
	#'ComponentType'{name=transfer,
			 typespec=#type{def='OBJECT IDENTIFIER'},
			 prop=mandatory},
    AbstractTrSeq =
	#'SEQUENCE'{components=[Abstract,Transfer]},
    Syntaxes =
	#'ComponentType'{name=syntaxes,
			 typespec=#type{def=AbstractTrSeq},
			 prop=mandatory},
    Fixed = #'ComponentType'{name=fixed,
			     typespec=#type{def='NULL'},
			     prop=mandatory},
    Negotiations =
	[Syntaxes,Syntax,Presentation_Cid,Context_negot,
	 Transfer_syntax,Fixed],
    Identification2 =
	#'ComponentType'{name=identification,
			 typespec=#type{def={'CHOICE',Negotiations}},
			 prop=mandatory},
    EmbeddedPdv_components =
	[Identification2,Data_value],
    
    %% The CHARACTER STRING type is represented by a SEQUENCE type
    %% with components: identification and string-value
    String_value = 
	#'ComponentType'{name='string-value',
			 typespec=#type{def='OCTET STRING'},
			 prop=mandatory},
    CharacterString_components =
	[Identification2,String_value],

    [{'EXTERNAL',
      #type{tag=[#tag{class='UNIVERSAL',
		      number=8,
		      type='IMPLICIT',
		      form=32}],
	    def=#'SEQUENCE'{components=
			    EXTERNAL_components1990}}},
     {'EMBEDDED PDV',
      #type{tag=[#tag{class='UNIVERSAL',
		      number=11,
		      type='IMPLICIT',
		      form=32}],
	    def=#'SEQUENCE'{components=EmbeddedPdv_components}}},
     {'CHARACTER STRING',
      #type{tag=[#tag{class='UNIVERSAL',
		      number=29,
		      type='IMPLICIT',
		      form=32}],
	    def=#'SEQUENCE'{components=CharacterString_components}}}
     ].


include_default_class(S, Module) ->
    _ = [include_default_class1(S, Module, ClassDef) ||
	    ClassDef <- default_class_list()],
	ok.

include_default_class1(S, Module, {Name,Ts0}) ->
    case asn1_db:dbget(Module, Name) of
	undefined ->
	    #objectclass{fields=Fields,
			 syntax={'WITH SYNTAX',Syntax0}} = Ts0,
	    Syntax = preprocess_syntax(S, Syntax0, Fields),
	    Ts = Ts0#objectclass{syntax={preprocessed_syntax,Syntax}},
	    C = #classdef{checked=true,module=Module,
			  name=Name,typespec=Ts},
	    asn1_db:dbput(Module, Name, C);
	_ ->
	    ok
    end.

default_class_list() ->
    [{'TYPE-IDENTIFIER',
      #objectclass{fields=[{fixedtypevaluefield,
			    id,
			    #type{tag=[?TAG_PRIMITIVE(?N_OBJECT_IDENTIFIER)],
				  def='OBJECT IDENTIFIER'},
			    'UNIQUE',
			    'MANDATORY'},
			   {typefield,'Type','MANDATORY'}],
		   syntax={'WITH SYNTAX',
			   [{typefieldreference,'Type'},
			    'IDENTIFIED',
			    'BY',
			    {valuefieldreference,id}]}}},
     {'ABSTRACT-SYNTAX',
      #objectclass{fields=[{fixedtypevaluefield,
			    id,
			    #type{tag=[?TAG_PRIMITIVE(?N_OBJECT_IDENTIFIER)],
				  def='OBJECT IDENTIFIER'},
			    'UNIQUE',
			    'MANDATORY'},
			   {typefield,'Type','MANDATORY'},
			   {fixedtypevaluefield,
			    property,
			    #type{tag=[?TAG_PRIMITIVE(?N_BIT_STRING)],
				  def={'BIT STRING',[]}},
			    undefined,
			    {'DEFAULT',
			     [0,1,0]}}],
		   syntax={'WITH SYNTAX',
			   [{typefieldreference,'Type'},
			    'IDENTIFIED',
			    'BY',
			    {valuefieldreference,id},
			    ['HAS',
			     'PROPERTY',
			     {valuefieldreference,property}]]}}}].

new_reference_name(Name) ->
    case get(asn1_reference) of
	undefined ->
	    put(asn1_reference,1),
	    list_to_atom(lists:concat([internal_,Name,"_",1]));
	Num when is_integer(Num) ->
	    put(asn1_reference,Num+1),
	    list_to_atom(lists:concat([internal_,Name,"_",Num+1]))
    end.

get_record_prefix_name(S) ->
    case lists:keysearch(record_name_prefix,1,S#state.options) of
	{value,{_,Prefix}} ->
	    Prefix;
	_ ->
	    ""
    end.

insert_once(S,Tab,Key) ->
    case get(top_module) of
	M when M == S#state.mname ->
	    asn1ct_gen:insert_once(Tab,Key),
	    ok;
	_ ->
	    skipped
    end.

check_fold(S0, [H|T], Check) ->
    Type = asn1_db:dbget(S0#state.mname, H),
    S = S0#state{error_context=Type},
    case Check(S, H, Type) of
	ok ->
	    check_fold(S, T, Check);
	Error ->
	    [Error|check_fold(S, T, Check)]
    end;
check_fold(_, [], Check) when is_function(Check, 3) -> [].

error_value(Value) when is_integer(Value) -> Value;
error_value(Value) when is_atom(Value) -> Value;
error_value(#type{def=Value}) when is_atom(Value) -> Value;
error_value(#type{def=Value}) -> error_value(Value);
error_value(RefOrType) ->
    try name_of_def(RefOrType) of
	Name -> Name
    catch _:_ ->
	    case get_datastr_name(RefOrType) of
		undefined -> RefOrType;
		Name -> Name
	    end
    end.

name_of_def(#'Externaltypereference'{type=N}) -> N;
name_of_def(#'Externalvaluereference'{value=N}) -> N.