aboutsummaryrefslogtreecommitdiffstats
path: root/erts/emulator/beam/erl_bif_lists.c
blob: e006d5712452d8f2823460523db4342532ed67ee (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 1999-2011. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 */

/*
 * BIFs logically belonging to the lists module.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include "sys.h"
#include "erl_vm.h"
#include "global.h"
#include "erl_process.h"
#include "error.h"
#include "bif.h"

static Eterm keyfind(int Bif, Process* p, Eterm Key, Eterm Pos, Eterm List);

static BIF_RETTYPE append(Process* p, Eterm A, Eterm B)
{
    Eterm list;
    Eterm copy;
    Eterm last;
    size_t need;
    Eterm* hp;
    int i;

    if ((i = erts_list_length(A)) < 0) {
	BIF_ERROR(p, BADARG);
    }
    if (i == 0) {
	BIF_RET(B);
    } else if (is_nil(B)) {
	BIF_RET(A);
    }

    need = 2*i;
    hp = HAlloc(p, need);
    list = A;
    copy = last = CONS(hp, CAR(list_val(list)), make_list(hp+2));
    list = CDR(list_val(list));
    hp += 2;
    i--;
    while(i--) {
	Eterm* listp = list_val(list);
	last = CONS(hp, CAR(listp), make_list(hp+2));
	list = CDR(listp);
	hp += 2;
    }
    CDR(list_val(last)) = B;
    BIF_RET(copy);
}

/*
 * erlang:'++'/2
 */

Eterm
ebif_plusplus_2(BIF_ALIST_2)
{
    return append(BIF_P, BIF_ARG_1, BIF_ARG_2);
}

BIF_RETTYPE append_2(BIF_ALIST_2)
{
    return append(BIF_P, BIF_ARG_1, BIF_ARG_2);
}

/*
 * erlang:'--'/2
 */

#define SMALL_VEC_SIZE 10
static Eterm subtract(Process* p, Eterm A, Eterm B)
{
    Eterm  list;
    Eterm* hp;
    Uint  need;
    Eterm  res;
    Eterm small_vec[SMALL_VEC_SIZE];	/* Preallocated memory for small lists */
    Eterm* vec_p;
    Eterm* vp;
    int     i;
    int     n;
    int     m;
    
    if ((n = erts_list_length(A)) < 0) {
	BIF_ERROR(p, BADARG);
    }
    if ((m = erts_list_length(B)) < 0) {
	BIF_ERROR(p, BADARG);
    }
    
    if (n == 0)
	BIF_RET(NIL);
    if (m == 0)
	BIF_RET(A);
    
    /* allocate element vector */
    if (n <= SMALL_VEC_SIZE)
	vec_p = small_vec;
    else
	vec_p = (Eterm*) erts_alloc(ERTS_ALC_T_TMP, n * sizeof(Eterm));
    
    /* PUT ALL ELEMENTS IN VP */
    vp = vec_p;
    list = A;
    i = n;
    while(i--) {
	Eterm* listp = list_val(list);
	*vp++ = CAR(listp);
	list = CDR(listp);
    }
    
    /* UNMARK ALL DELETED CELLS */
    list = B;
    m = 0;  /* number of deleted elements */
    while(is_list(list)) {
	Eterm* listp = list_val(list);
	Eterm  elem = CAR(listp);
	i = n;
	vp = vec_p;
	while(i--) {
	    if (is_value(*vp) && eq(*vp, elem)) {
		*vp = THE_NON_VALUE;
		m++;
		break;
	    }
	    vp++;
	}
	list = CDR(listp);
    }
    
    if (m == n)      /* All deleted ? */
	res = NIL;
    else if (m == 0)  /* None deleted ? */
	res = A;
    else {			/* REBUILD LIST */
	res = NIL;
	need = 2*(n - m);
	hp = HAlloc(p, need);
	vp = vec_p + n - 1;
	while(vp >= vec_p) {
	    if (is_value(*vp)) {
		res = CONS(hp, *vp, res);
		hp += 2;
	    }
	    vp--;
	}
    }
    if (vec_p != small_vec)
	erts_free(ERTS_ALC_T_TMP, (void *) vec_p);
    BIF_RET(res);
}

BIF_RETTYPE ebif_minusminus_2(BIF_ALIST_2)
{
    return subtract(BIF_P, BIF_ARG_1, BIF_ARG_2);
}

BIF_RETTYPE subtract_2(BIF_ALIST_2)
{
    return subtract(BIF_P, BIF_ARG_1, BIF_ARG_2);
}

BIF_RETTYPE lists_member_2(BIF_ALIST_2)
{
    Eterm term;
    Eterm list;
    Eterm item;
    int non_immed_key;
    int max_iter = 10 * CONTEXT_REDS;

    if (is_nil(BIF_ARG_2)) {
	BIF_RET(am_false);
    } else if (is_not_list(BIF_ARG_2)) {
	BIF_ERROR(BIF_P, BADARG);
    }
    
    term = BIF_ARG_1;
    non_immed_key = is_not_immed(term);
    list = BIF_ARG_2;
    while (is_list(list)) {
	if (--max_iter < 0) {
	    BUMP_ALL_REDS(BIF_P);
	    BIF_TRAP2(bif_export[BIF_lists_member_2], BIF_P, term, list);
	}
	item = CAR(list_val(list));
	if ((item == term) || (non_immed_key && eq(item, term))) {
	    BIF_RET2(am_true, CONTEXT_REDS - max_iter/10);
	}
	list = CDR(list_val(list));
    }
    if (is_not_nil(list))  {
	BIF_ERROR(BIF_P, BADARG);
    }
    BIF_RET2(am_false, CONTEXT_REDS - max_iter/10);
}

BIF_RETTYPE lists_reverse_2(BIF_ALIST_2)
{
    Eterm list;
    Eterm tmp_list;
    Eterm result;
    Eterm* hp;
    Uint n;
    int max_iter;
    
    /*
     * Handle legal and illegal non-lists quickly.
     */
    if (is_nil(BIF_ARG_1)) {
	BIF_RET(BIF_ARG_2);
    } else if (is_not_list(BIF_ARG_1)) {
    error:
	BIF_ERROR(BIF_P, BADARG);
    }

    /*
     * First use the rest of the remaning heap space.
     */
    list = BIF_ARG_1;
    result = BIF_ARG_2;
    hp = HEAP_TOP(BIF_P);
    n = HeapWordsLeft(BIF_P) / 2;
    while (n != 0 && is_list(list)) {
	Eterm* pair = list_val(list);
	result = CONS(hp, CAR(pair), result);
	list = CDR(pair);
	hp += 2;
	n--;
    }
    HEAP_TOP(BIF_P) = hp;
    if (is_nil(list)) {
	BIF_RET(result);
    }

    /*
     * Calculate length of remaining list (up to a suitable limit).
     */
    max_iter = CONTEXT_REDS * 40;
    n = 0;
    tmp_list = list;
    while (max_iter-- > 0 && is_list(tmp_list)) {
	tmp_list = CDR(list_val(tmp_list));
	n++;
    }
    if (is_not_nil(tmp_list) && is_not_list(tmp_list)) {
	goto error;
    }

    /*
     * Now do one HAlloc() and continue reversing.
     */
    hp = HAlloc(BIF_P, 2*n);
    while (n != 0 && is_list(list)) {
	Eterm* pair = list_val(list);
	result = CONS(hp, CAR(pair), result);
	list = CDR(pair);
	hp += 2;
	n--;
    }
    if (is_nil(list)) {
	BIF_RET(result);
    } else {
	BUMP_ALL_REDS(BIF_P);
	BIF_TRAP2(bif_export[BIF_lists_reverse_2], BIF_P, list, result);
    }
}

BIF_RETTYPE
lists_keymember_3(BIF_ALIST_3)
{
    Eterm res;

    res = keyfind(BIF_lists_keymember_3, BIF_P,
		  BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
    if (is_value(res) && is_tuple(res)) {
	return am_true;
    } else {
	return res;
    }
}

BIF_RETTYPE
lists_keysearch_3(BIF_ALIST_3)
{
    Eterm res;
    
    res = keyfind(BIF_lists_keysearch_3, BIF_P,
		  BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
    if (is_non_value(res) || is_not_tuple(res)) {
	return res;
    } else {			/* Tuple */
	Eterm* hp = HAlloc(BIF_P, 3);
	return TUPLE2(hp, am_value, res);
    }
}

BIF_RETTYPE
lists_keyfind_3(BIF_ALIST_3)
{
    return keyfind(BIF_lists_keyfind_3, BIF_P,
		   BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
}

static Eterm
keyfind(int Bif, Process* p, Eterm Key, Eterm Pos, Eterm List)
{
    int max_iter = 10 * CONTEXT_REDS;
    Sint pos;
    Eterm term;

    if (!is_small(Pos) || (pos = signed_val(Pos)) < 1) {
	BIF_ERROR(p, BADARG);
    }

    if (is_small(Key)) {
	double float_key = (double) signed_val(Key);

	while (is_list(List)) {
	    if (--max_iter < 0) {
		BUMP_ALL_REDS(p);
		BIF_TRAP3(bif_export[Bif], p, Key, Pos, List);
	    }
	    term = CAR(list_val(List));
	    List = CDR(list_val(List));
	    if (is_tuple(term)) {
		Eterm *tuple_ptr = tuple_val(term);
		if (pos <= arityval(*tuple_ptr)) {
		    Eterm element = tuple_ptr[pos];
		    if (Key == element) {
			return term;
		    } else if (is_float(element)) {
			FloatDef f;

			GET_DOUBLE(element, f);
			if (f.fd == float_key) {
			    return term;
			}
		    }
		}
	    }
	}
    } else if (is_immed(Key)) {
	while (is_list(List)) {
	    if (--max_iter < 0) {
		BUMP_ALL_REDS(p);
		BIF_TRAP3(bif_export[Bif], p, Key, Pos, List);
	    }
	    term = CAR(list_val(List));
	    List = CDR(list_val(List));
	    if (is_tuple(term)) {
		Eterm *tuple_ptr = tuple_val(term);
		if (pos <= arityval(*tuple_ptr)) {
		    Eterm element = tuple_ptr[pos];
		    if (Key == element) {
			return term;
		    }
		}
	    }
	}
    } else {
	while (is_list(List)) {
	    if (--max_iter < 0) {
		BUMP_ALL_REDS(p);
		BIF_TRAP3(bif_export[Bif], p, Key, Pos, List);
	    }
	    term = CAR(list_val(List));
	    List = CDR(list_val(List));
	    if (is_tuple(term)) {
		Eterm *tuple_ptr = tuple_val(term);
		if (pos <= arityval(*tuple_ptr)) {
		    Eterm element = tuple_ptr[pos];
		    if (CMP_EQ(Key, element)) {
			return term;
		    }
		}
	    }
	}
    }

    if (is_not_nil(List))  {
	BIF_ERROR(p, BADARG);
    }
    return am_false;
}