path: root/erts/emulator/beam/erl_nif.c

/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2009-2014. 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%
 */
/* Erlang Native InterFace
 */

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

#include "erl_nif.h"

#include "sys.h"
#include "global.h"
#include "erl_binary.h"
#include "bif.h"
#include "error.h"
#include "big.h"
#include "erl_map.h"
#include "beam_bp.h"
#include "erl_thr_progress.h"
#include "dtrace-wrapper.h"
#include "erl_process.h"
#include "erl_bif_unique.h"
#if defined(USE_DYNAMIC_TRACE) && (defined(USE_DTRACE) || defined(USE_SYSTEMTAP))
#define HAVE_USE_DTRACE 1
#endif

#include <limits.h>
#include <stddef.h> /* offsetof */


/* Information about a loaded nif library.
 * Each successful call to erlang:load_nif will allocate an instance of
 * erl_module_nif. Two calls opening the same library will thus have the same
 * 'handle'.
 */
struct erl_module_nif {
    void* priv_data;
    void* handle;             /* "dlopen" */
    struct enif_entry_t* entry;
    erts_refc_t rt_cnt;       /* number of resource types */
    erts_refc_t rt_dtor_cnt;  /* number of resource types with destructors */
    Module* mod;           /* Can be NULL if orphan with dtor-resources left */ 
};

#ifdef DEBUG
#  define READONLY_CHECK
#endif
#ifdef READONLY_CHECK
#  define ADD_READONLY_CHECK(ENV,PTR,SIZE) add_readonly_check(ENV,PTR,SIZE)
static void add_readonly_check(ErlNifEnv*, unsigned char* ptr, unsigned sz);
#else
#  define ADD_READONLY_CHECK(ENV,PTR,SIZE) ((void)0)
#endif

#ifdef DEBUG
static int is_offheap(const ErlOffHeap* off_heap);
#endif

#ifdef USE_VM_PROBES
void dtrace_nifenv_str(ErlNifEnv *, char *);
#endif

#define MIN_HEAP_FRAG_SZ 200
static Eterm* alloc_heap_heavy(ErlNifEnv* env, unsigned need, Eterm* hp);

static ERTS_INLINE Eterm* alloc_heap(ErlNifEnv* env, unsigned need)
{
    Eterm* hp = env->hp;
    env->hp += need;
    if (env->hp <= env->hp_end) {
	return hp;
    }
    return alloc_heap_heavy(env, need, hp);
}

static Eterm* alloc_heap_heavy(ErlNifEnv* env, unsigned need, Eterm* hp)
{    
    env->hp = hp;
    if (env->heap_frag == NULL) {       
	ASSERT(HEAP_LIMIT(env->proc) == env->hp_end);
	HEAP_TOP(env->proc) = env->hp;	
    }
    else {
	env->heap_frag->used_size = hp - env->heap_frag->mem;
	ASSERT(env->heap_frag->used_size <= env->heap_frag->alloc_size);
    }
    hp = erts_heap_alloc(env->proc, need, MIN_HEAP_FRAG_SZ);
    env->heap_frag = MBUF(env->proc);
    env->hp = hp + need;
    env->hp_end = env->heap_frag->mem + env->heap_frag->alloc_size;

    return hp;
}

#if SIZEOF_LONG != ERTS_SIZEOF_ETERM
static ERTS_INLINE void ensure_heap(ErlNifEnv* env, unsigned may_need)
{
    if (env->hp + may_need > env->hp_end) {
	alloc_heap_heavy(env, may_need, env->hp);
	env->hp -= may_need;
    }
}
#endif

void erts_pre_nif(ErlNifEnv* env, Process* p, struct erl_module_nif* mod_nif)
{
    env->mod_nif = mod_nif;
    env->proc = p;
    env->hp = HEAP_TOP(p);
    env->hp_end = HEAP_LIMIT(p);
    env->heap_frag = NULL;
    env->fpe_was_unmasked = erts_block_fpe();
    env->tmp_obj_list = NULL;
    env->exception_thrown = 0;
}

static void pre_nif_noproc(ErlNifEnv* env, struct erl_module_nif* mod_nif)
{
    env->mod_nif = mod_nif;
    env->proc = NULL;
    env->hp = NULL;
    env->hp_end = NULL;
    env->heap_frag = NULL;
    env->fpe_was_unmasked = erts_block_fpe();
    env->tmp_obj_list = NULL;
}

/* Temporary object header, auto-deallocated when NIF returns
 * or when independent environment is cleared.
 */
struct enif_tmp_obj_t {
    struct enif_tmp_obj_t* next;
    void (*dtor)(struct enif_tmp_obj_t*);
    ErtsAlcType_t allocator;
    /*char data[];*/
};

static ERTS_INLINE void free_tmp_objs(ErlNifEnv* env)
{
    while (env->tmp_obj_list != NULL) {
	struct enif_tmp_obj_t* free_me = env->tmp_obj_list;
	env->tmp_obj_list = free_me->next;
	free_me->dtor(free_me);
    }
}

void erts_post_nif(ErlNifEnv* env)
{
    erts_unblock_fpe(env->fpe_was_unmasked);
    if (env->heap_frag == NULL) {
	ASSERT(env->hp_end == HEAP_LIMIT(env->proc));
	ASSERT(env->hp >= HEAP_TOP(env->proc));
	ASSERT(env->hp <= HEAP_LIMIT(env->proc));	
	HEAP_TOP(env->proc) = env->hp;
    }
    else {
	ASSERT(env->hp_end != HEAP_LIMIT(env->proc));
	ASSERT(env->hp_end - env->hp <= env->heap_frag->alloc_size);
	env->heap_frag->used_size = env->hp - env->heap_frag->mem;
	ASSERT(env->heap_frag->used_size <= env->heap_frag->alloc_size);
    }
    free_tmp_objs(env);
}

static void post_nif_noproc(ErlNifEnv* env)
{
    erts_unblock_fpe(env->fpe_was_unmasked);
    free_tmp_objs(env);
}


/* Flush out our cached heap pointers to allow an ordinary HAlloc
*/
static void flush_env(ErlNifEnv* env)
{
    if (env->heap_frag == NULL) {
	ASSERT(env->hp_end == HEAP_LIMIT(env->proc));
	ASSERT(env->hp >= HEAP_TOP(env->proc));
	ASSERT(env->hp <= HEAP_LIMIT(env->proc));	
	HEAP_TOP(env->proc) = env->hp;
    }
    else {
	ASSERT(env->hp_end != HEAP_LIMIT(env->proc));
	ASSERT(env->hp_end - env->hp <= env->heap_frag->alloc_size);
	env->heap_frag->used_size = env->hp - env->heap_frag->mem;
	ASSERT(env->heap_frag->used_size <= env->heap_frag->alloc_size);
    }
}

/* Restore cached heap pointers to allow alloc_heap again.
*/
static void cache_env(ErlNifEnv* env)
{
    if (env->heap_frag == NULL) {
	ASSERT(env->hp_end == HEAP_LIMIT(env->proc));
	ASSERT(env->hp <= HEAP_TOP(env->proc));
	ASSERT(env->hp <= HEAP_LIMIT(env->proc));	
	env->hp = HEAP_TOP(env->proc);
    }
    else {
	ASSERT(env->hp_end != HEAP_LIMIT(env->proc));
	ASSERT(env->hp_end - env->hp <= env->heap_frag->alloc_size);       
	env->heap_frag = MBUF(env->proc);
	ASSERT(env->heap_frag != NULL);
	env->hp = env->heap_frag->mem + env->heap_frag->used_size;
	env->hp_end = env->heap_frag->mem + env->heap_frag->alloc_size;
    }
}
void* enif_priv_data(ErlNifEnv* env)
{
    return env->mod_nif->priv_data;
}

void* enif_alloc(size_t size)
{
    return erts_alloc_fnf(ERTS_ALC_T_NIF, (Uint) size);
}

void* enif_realloc(void* ptr, size_t size)
{
    return erts_realloc_fnf(ERTS_ALC_T_NIF, ptr, size);
}

void enif_free(void* ptr)
{
    erts_free(ERTS_ALC_T_NIF, ptr);
}

struct enif_msg_environment_t
{
    ErlNifEnv env;
    Process phony_proc;
};

ErlNifEnv* enif_alloc_env(void)
{
    struct enif_msg_environment_t* msg_env =
	erts_alloc_fnf(ERTS_ALC_T_NIF, sizeof(struct enif_msg_environment_t));
    Eterm* phony_heap = (Eterm*) msg_env; /* dummy non-NULL ptr */
	
    msg_env->env.hp = phony_heap; 
    msg_env->env.hp_end = phony_heap;
    msg_env->env.heap_frag = NULL;
    msg_env->env.mod_nif = NULL;
    msg_env->env.tmp_obj_list = NULL;
    msg_env->env.proc = &msg_env->phony_proc;
    memset(&msg_env->phony_proc, 0, sizeof(Process));
    HEAP_START(&msg_env->phony_proc) = phony_heap;
    HEAP_TOP(&msg_env->phony_proc) = phony_heap;
    HEAP_LIMIT(&msg_env->phony_proc) = phony_heap;
    HEAP_END(&msg_env->phony_proc) = phony_heap;
    MBUF(&msg_env->phony_proc) = NULL;
    msg_env->phony_proc.common.id = ERTS_INVALID_PID;
#ifdef FORCE_HEAP_FRAGS
    msg_env->phony_proc.space_verified = 0;
    msg_env->phony_proc.space_verified_from = NULL;
#endif
    return &msg_env->env;
}
void enif_free_env(ErlNifEnv* env)
{
    enif_clear_env(env);
    erts_free(ERTS_ALC_T_NIF, env);
}

static ERTS_INLINE void clear_offheap(ErlOffHeap* oh)
{
    oh->first = NULL;
    oh->overhead = 0;
}

void enif_clear_env(ErlNifEnv* env)
{
    struct enif_msg_environment_t* menv = (struct enif_msg_environment_t*)env;
    Process* p = &menv->phony_proc;
    ASSERT(p == menv->env.proc);
    ASSERT(p->common.id == ERTS_INVALID_PID);
    ASSERT(MBUF(p) == menv->env.heap_frag);
    if (MBUF(p) != NULL) {
	erts_cleanup_offheap(&MSO(p));
	clear_offheap(&MSO(p));
	free_message_buffer(MBUF(p));
	MBUF(p) = NULL;
	menv->env.heap_frag = NULL;
    }
    ASSERT(HEAP_TOP(p) == HEAP_END(p));
    menv->env.hp = menv->env.hp_end = HEAP_TOP(p);
    
    ASSERT(!is_offheap(&MSO(p)));
    free_tmp_objs(env);
}
int enif_send(ErlNifEnv* env, const ErlNifPid* to_pid,
	      ErlNifEnv* msg_env, ERL_NIF_TERM msg)
{
    struct enif_msg_environment_t* menv = (struct enif_msg_environment_t*)msg_env;
    ErtsProcLocks rp_locks = 0;
    Process* rp;
    Process* c_p;
    ErlHeapFragment* frags;
    Eterm receiver = to_pid->pid;
    int flush_me = 0;
    int scheduler = erts_get_scheduler_id() != 0;

    if (env != NULL) {
	c_p = env->proc;
	if (receiver == c_p->common.id) {
	    rp_locks = ERTS_PROC_LOCK_MAIN;
	    flush_me = 1;
	}
    }
    else {
#ifdef ERTS_SMP
	c_p = NULL;
#else
	erts_exit(ERTS_ABORT_EXIT,"enif_send: env==NULL on non-SMP VM");
#endif
    }    

    rp = (scheduler
	  ? erts_proc_lookup(receiver)
	  : erts_pid2proc_opt(c_p, ERTS_PROC_LOCK_MAIN,
			      receiver, rp_locks, ERTS_P2P_FLG_INC_REFC));
    if (rp == NULL) {
	ASSERT(env == NULL || receiver != c_p->common.id);
	return 0;
    }
    flush_env(msg_env);
    frags = menv->env.heap_frag; 
    ASSERT(frags == MBUF(&menv->phony_proc));
    if (frags != NULL) {
	/* Move all offheap's from phony proc to the first fragment.
	   Quick and dirty, but erts_move_msg_mbuf_to_heap doesn't care. */
	ASSERT(!is_offheap(&frags->off_heap));
	frags->off_heap = MSO(&menv->phony_proc);
	clear_offheap(&MSO(&menv->phony_proc));
	menv->env.heap_frag = NULL; 
	MBUF(&menv->phony_proc) = NULL;
    }
    ASSERT(!is_offheap(&MSO(&menv->phony_proc)));

    if (flush_me) {	
	flush_env(env); /* Needed for ERTS_HOLE_CHECK */ 
    }
    erts_queue_message(rp, &rp_locks, frags, msg, am_undefined);
    if (c_p == rp)
	rp_locks &= ~ERTS_PROC_LOCK_MAIN;
    if (rp_locks)
	erts_smp_proc_unlock(rp, rp_locks);
    if (!scheduler)
	erts_proc_dec_refc(rp);
    if (flush_me) {
	cache_env(env);
    }
    return 1;
}

ERL_NIF_TERM enif_make_copy(ErlNifEnv* dst_env, ERL_NIF_TERM src_term)
{
    Uint sz;
    Eterm* hp;
    sz = size_object(src_term);
    hp = alloc_heap(dst_env, sz);
    return copy_struct(src_term, sz, &hp, &MSO(dst_env->proc));
}


#ifdef DEBUG
static int is_offheap(const ErlOffHeap* oh)
{
    return oh->first != NULL;
}
#endif

ErlNifPid* enif_self(ErlNifEnv* caller_env, ErlNifPid* pid)
{
    pid->pid = caller_env->proc->common.id;
    return pid;
}
int enif_get_local_pid(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifPid* pid)
{
    return is_internal_pid(term) ? (pid->pid=term, 1) : 0;
}

int enif_is_atom(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_atom(term);
}

int enif_is_binary(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_binary(term) && (binary_bitsize(term) % 8 == 0);
}

int enif_is_empty_list(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_nil(term);
}

int enif_is_fun(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_fun(term);
}

int enif_is_pid(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_pid(term);
}

int enif_is_port(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_port(term);
}

int enif_is_ref(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_ref(term);
}

int enif_is_tuple(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_tuple(term);
}

int enif_is_list(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_list(term) || is_nil(term);
}

int enif_is_exception(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return env->exception_thrown && term == THE_NON_VALUE;
}

int enif_is_number(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_number(term);
}

static ERTS_INLINE int is_proc_bound(ErlNifEnv* env)
{
    return env->mod_nif != NULL;
}

static void aligned_binary_dtor(struct enif_tmp_obj_t* obj)
{
    erts_free_aligned_binary_bytes_extra((byte*)obj, obj->allocator);
}

int enif_inspect_binary(ErlNifEnv* env, Eterm bin_term, ErlNifBinary* bin)
{
    ErtsAlcType_t allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF;
    union {
	struct enif_tmp_obj_t* tmp;
	byte* raw_ptr;
    }u;

    if (is_boxed(bin_term) && *binary_val(bin_term) == HEADER_SUB_BIN) {
	ErlSubBin* sb = (ErlSubBin*) binary_val(bin_term);
	if (sb->is_writable) {
	    ProcBin* pb = (ProcBin*) binary_val(sb->orig);
	    ASSERT(pb->thing_word == HEADER_PROC_BIN);
	    if (pb->flags) {
		erts_emasculate_writable_binary(pb);
		sb->is_writable = 0;
	    }
	}
    }
    u.tmp = NULL;
    bin->data = erts_get_aligned_binary_bytes_extra(bin_term, &u.raw_ptr, allocator,
						    sizeof(struct enif_tmp_obj_t));
    if (bin->data == NULL) {
	return 0;
    }
    if (u.tmp != NULL) {
	u.tmp->allocator = allocator;
	u.tmp->next = env->tmp_obj_list;
	u.tmp->dtor = &aligned_binary_dtor;
	env->tmp_obj_list = u.tmp;
    }
    bin->bin_term = bin_term;
    bin->size = binary_size(bin_term);
    bin->ref_bin = NULL;
    ADD_READONLY_CHECK(env, bin->data, bin->size); 
    return 1;
}

static void tmp_alloc_dtor(struct enif_tmp_obj_t* obj)
{
    erts_free(obj->allocator,  obj);
}

int enif_inspect_iolist_as_binary(ErlNifEnv* env, Eterm term, ErlNifBinary* bin)
{
    struct enif_tmp_obj_t* tobj;
    ErtsAlcType_t allocator;
    ErlDrvSizeT sz;
    if (is_binary(term)) {
	return enif_inspect_binary(env,term,bin);
    }
    if (is_nil(term)) {
	bin->data = (unsigned char*) &bin->data; /* dummy non-NULL */
	bin->size = 0;
	bin->bin_term = THE_NON_VALUE;
	bin->ref_bin = NULL;
	return 1;
    }
    if (erts_iolist_size(term, &sz)) {
	return 0;
    }

    allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF;
    tobj = erts_alloc(allocator, sz + sizeof(struct enif_tmp_obj_t));
    tobj->allocator = allocator;
    tobj->next = env->tmp_obj_list;
    tobj->dtor = &tmp_alloc_dtor;
    env->tmp_obj_list = tobj;

    bin->data = (unsigned char*) &tobj[1]; 
    bin->size = sz;
    bin->bin_term = THE_NON_VALUE;
    bin->ref_bin = NULL;
    erts_iolist_to_buf(term, (char*) bin->data, sz);
    ADD_READONLY_CHECK(env, bin->data, bin->size); 
    return 1;
}

int enif_alloc_binary(size_t size, ErlNifBinary* bin)
{
    Binary* refbin;

    refbin = erts_bin_drv_alloc_fnf(size); /* BUGBUG: alloc type? */
    if (refbin == NULL) {
	return 0; /* The NIF must take action */
    }
    erts_refc_init(&refbin->refc, 1);

    bin->size = size;
    bin->data = (unsigned char*) refbin->orig_bytes;
    bin->bin_term = THE_NON_VALUE;
    bin->ref_bin = refbin;
    return 1;
}

int enif_realloc_binary(ErlNifBinary* bin, size_t size)
{
    if (bin->ref_bin != NULL) {
	Binary* oldbin;
	Binary* newbin;
    
	oldbin = (Binary*) bin->ref_bin; 
	newbin = (Binary *) erts_bin_realloc_fnf(oldbin, size);
	if (!newbin) {
	    return 0;
	}    
	bin->ref_bin = newbin;
	bin->data = (unsigned char*) newbin->orig_bytes;
	bin->size = size;
    }
    else {
	unsigned char* old_data = bin->data;
	size_t cpy_sz = (size < bin->size ? size : bin->size);  
	enif_alloc_binary(size, bin);
	sys_memcpy(bin->data, old_data, cpy_sz); 
    }
    return 1;
}


void enif_release_binary(ErlNifBinary* bin)
{
    if (bin->ref_bin != NULL) {
	Binary* refbin = bin->ref_bin;
	ASSERT(bin->bin_term == THE_NON_VALUE);
	if (erts_refc_dectest(&refbin->refc, 0) == 0) {
	    erts_bin_free(refbin);
	}
    }
#ifdef DEBUG
    bin->data = NULL;
    bin->bin_term = THE_NON_VALUE;
    bin->ref_bin = NULL;
#endif
}

unsigned char* enif_make_new_binary(ErlNifEnv* env, size_t size,
				    ERL_NIF_TERM* termp)
{
    flush_env(env);
    *termp = new_binary(env->proc, NULL, size);
    cache_env(env);
    return binary_bytes(*termp);
}

int enif_is_identical(Eterm lhs, Eterm rhs)
{
    return EQ(lhs,rhs);
}

int enif_compare(Eterm lhs, Eterm rhs)
{
    Sint result = CMP(lhs,rhs);

    if (result < 0) {
        return -1;
    } else if (result > 0) {
        return 1;
    }

    return result;
}

int enif_get_tuple(ErlNifEnv* env, Eterm tpl, int* arity, const Eterm** array)
{
    Eterm* ptr;
    if (is_not_tuple(tpl)) {
	return 0;
    }
    ptr = tuple_val(tpl);
    *arity = arityval(*ptr);
    *array = ptr+1;
    return 1;
}

int enif_get_string(ErlNifEnv *env, ERL_NIF_TERM list, char* buf, unsigned len,
		    ErlNifCharEncoding encoding)
{
    Eterm* listptr;
    int n = 0;

    ASSERT(encoding == ERL_NIF_LATIN1);
    if (len < 1) {
	return 0;
    }
    while (is_not_nil(list)) { 	    
	if (is_not_list(list)) {
	    buf[n] = '\0';
	    return 0;
	}
	listptr = list_val(list);
    
	if (!is_byte(*listptr)) {
	    buf[n] = '\0';
	    return 0;
	}
	buf[n++] = unsigned_val(*listptr);
	if (n >= len) {
	    buf[n-1] = '\0'; /* truncate */
	    return -len;
	}
	list = CDR(listptr);
    }
    buf[n] = '\0';
    return n + 1;
}

Eterm enif_make_binary(ErlNifEnv* env, ErlNifBinary* bin)
{
    if (bin->bin_term != THE_NON_VALUE) {
	return bin->bin_term;
    }
    else if (bin->ref_bin != NULL) {
	Binary* bptr = bin->ref_bin;
	ProcBin* pb;
	Eterm bin_term;
	
	/* !! Copy-paste from new_binary() !! */
	pb = (ProcBin *) alloc_heap(env, PROC_BIN_SIZE);
	pb->thing_word = HEADER_PROC_BIN;
	pb->size = bptr->orig_size;
	pb->next = MSO(env->proc).first;
	MSO(env->proc).first = (struct erl_off_heap_header*) pb;
	pb->val = bptr;
	pb->bytes = (byte*) bptr->orig_bytes;
	pb->flags = 0;
	
	OH_OVERHEAD(&(MSO(env->proc)), pb->size / sizeof(Eterm));
	bin_term = make_binary(pb);	
	if (erts_refc_read(&bptr->refc, 1) == 1) {
	    /* Total ownership transfer */
	    bin->ref_bin = NULL;
	    bin->bin_term = bin_term;
	}
	return bin_term;
    }
    else {
	flush_env(env);
	bin->bin_term = new_binary(env->proc, bin->data, bin->size);
	cache_env(env);
	return bin->bin_term;
    }
}

Eterm enif_make_sub_binary(ErlNifEnv* env, ERL_NIF_TERM bin_term,
			   size_t pos, size_t size)
{
    ErlSubBin* sb;
    Eterm orig;
    Uint offset, bit_offset, bit_size; 
#ifdef DEBUG
    unsigned src_size;

    ASSERT(is_binary(bin_term));
    src_size = binary_size(bin_term);
    ASSERT(pos <= src_size);
    ASSERT(size <= src_size);
    ASSERT(pos + size <= src_size);   
#endif
    sb = (ErlSubBin*) alloc_heap(env, ERL_SUB_BIN_SIZE);
    ERTS_GET_REAL_BIN(bin_term, orig, offset, bit_offset, bit_size);
    sb->thing_word = HEADER_SUB_BIN;
    sb->size = size;
    sb->offs = offset + pos;
    sb->orig = orig;
    sb->bitoffs = bit_offset;
    sb->bitsize = 0;
    sb->is_writable = 0;
    return make_binary(sb);
}


Eterm enif_make_badarg(ErlNifEnv* env)
{
    return enif_raise_exception(env, am_badarg);
}

Eterm enif_raise_exception(ErlNifEnv* env, ERL_NIF_TERM reason)
{
    env->exception_thrown = 1;
    env->proc->fvalue = reason;
    BIF_ERROR(env->proc, EXC_ERROR);
}

int enif_has_pending_exception(ErlNifEnv* env, ERL_NIF_TERM* reason)
{
    if (env->exception_thrown && reason != NULL) {
	*reason = env->proc->fvalue;
    }
    return env->exception_thrown;
}

int enif_get_atom(ErlNifEnv* env, Eterm atom, char* buf, unsigned len,
		  ErlNifCharEncoding encoding)
{
    Atom* ap;
    ASSERT(encoding == ERL_NIF_LATIN1);
    if (is_not_atom(atom) || len==0) {
	return 0;
    }
    ap = atom_tab(atom_val(atom));

    if (ap->latin1_chars < 0 || ap->latin1_chars >= len) {
	return 0;
    }
    if (ap->latin1_chars == ap->len) {
	sys_memcpy(buf, ap->name, ap->len);
    }
    else {
	int dlen = erts_utf8_to_latin1((byte*)buf, ap->name, ap->len);
	ASSERT(dlen == ap->latin1_chars); (void)dlen;
    }
    buf[ap->latin1_chars] = '\0';
    return ap->latin1_chars + 1;
}

int enif_get_int(ErlNifEnv* env, Eterm term, int* ip)
{
#if SIZEOF_INT ==  ERTS_SIZEOF_ETERM
    return term_to_Sint(term, (Sint*)ip);
#elif (SIZEOF_LONG ==  ERTS_SIZEOF_ETERM) || \
  (SIZEOF_LONG_LONG ==  ERTS_SIZEOF_ETERM)
    Sint i;
    if (!term_to_Sint(term, &i) || i < INT_MIN || i > INT_MAX) {
	return 0;
    }
    *ip = (int) i;
    return 1;
#else
#  error Unknown word size 
#endif     
}

int enif_get_uint(ErlNifEnv* env, Eterm term, unsigned* ip)
{
#if SIZEOF_INT == ERTS_SIZEOF_ETERM
    return term_to_Uint(term, (Uint*)ip);
#elif (SIZEOF_LONG == ERTS_SIZEOF_ETERM) || \
  (SIZEOF_LONG_LONG ==  ERTS_SIZEOF_ETERM)
    Uint i;
    if (!term_to_Uint(term, &i) || i > UINT_MAX) {
	return 0;
    }
    *ip = (unsigned) i;
    return 1;
#endif     
}

int enif_get_long(ErlNifEnv* env, Eterm term, long* ip)
{
#if SIZEOF_LONG == ERTS_SIZEOF_ETERM
    return term_to_Sint(term, ip);
#elif SIZEOF_LONG == 8
    return term_to_Sint64(term, ip);
#elif SIZEOF_LONG == SIZEOF_INT
    int tmp,ret;
    ret = enif_get_int(env,term,&tmp);
    if (ret) {
      *ip = (long) tmp;
    }
    return ret;
#else
#  error Unknown long word size 
#endif     
}

int enif_get_ulong(ErlNifEnv* env, Eterm term, unsigned long* ip)
{
#if SIZEOF_LONG == ERTS_SIZEOF_ETERM
    return term_to_Uint(term, ip);
#elif SIZEOF_LONG == 8
    return term_to_Uint64(term, ip);
#elif SIZEOF_LONG == SIZEOF_INT
    int ret;
    unsigned int tmp;
    ret = enif_get_uint(env,term,&tmp);
    if (ret) {
      *ip = (unsigned long) tmp;
    }
    return ret;
#else
#  error Unknown long word size 
#endif     
}

#if HAVE_INT64 && SIZEOF_LONG != 8
int enif_get_int64(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifSInt64* ip)
{
    return term_to_Sint64(term, ip);
}

int enif_get_uint64(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifUInt64* ip)
{
    return term_to_Uint64(term, ip);
}
#endif /* HAVE_INT64 && SIZEOF_LONG != 8 */

int enif_get_double(ErlNifEnv* env, ERL_NIF_TERM term, double* dp)
{
    FloatDef f;
    if (is_not_float(term)) {
	return 0;
    }
    GET_DOUBLE(term, f);
    *dp = f.fd;
    return 1;
}

int enif_get_atom_length(ErlNifEnv* env, Eterm atom, unsigned* len,
			 ErlNifCharEncoding enc)
{
    Atom* ap;
    ASSERT(enc == ERL_NIF_LATIN1);
    if (is_not_atom(atom)) return 0;
    ap = atom_tab(atom_val(atom));
    if (ap->latin1_chars < 0) {
	return 0;
    }
    *len = ap->latin1_chars;
    return 1;
}

int enif_get_list_cell(ErlNifEnv* env, Eterm term, Eterm* head, Eterm* tail)
{
    Eterm* val;
    if (is_not_list(term)) return 0;
    val = list_val(term);
    *head = CAR(val);
    *tail = CDR(val);
    return 1;
}

int enif_get_list_length(ErlNifEnv* env, Eterm term, unsigned* len)
{
    if (is_not_list(term) && is_not_nil(term)) return 0;
    *len = erts_list_length(term);
    return 1;
}

ERL_NIF_TERM enif_make_int(ErlNifEnv* env, int i)
{
#if SIZEOF_INT == ERTS_SIZEOF_ETERM
    return IS_SSMALL(i) ? make_small(i) : small_to_big(i,alloc_heap(env,2));
#elif (SIZEOF_LONG == ERTS_SIZEOF_ETERM) || \
  (SIZEOF_LONG_LONG == ERTS_SIZEOF_ETERM)
    return make_small(i);
#endif
}

ERL_NIF_TERM enif_make_uint(ErlNifEnv* env, unsigned i)
{
#if SIZEOF_INT == ERTS_SIZEOF_ETERM
    return IS_USMALL(0,i) ? make_small(i) : uint_to_big(i,alloc_heap(env,2));
#elif (SIZEOF_LONG ==  ERTS_SIZEOF_ETERM) || \
  (SIZEOF_LONG_LONG ==  ERTS_SIZEOF_ETERM)
    return make_small(i);
#endif
}

ERL_NIF_TERM enif_make_long(ErlNifEnv* env, long i)
{
    if (IS_SSMALL(i)) {
	return make_small(i);
    }
#if SIZEOF_LONG == ERTS_SIZEOF_ETERM
    return small_to_big(i, alloc_heap(env,2));
#elif SIZEOF_LONG_LONG ==  ERTS_SIZEOF_ETERM
    return make_small(i);
#elif SIZEOF_LONG == 8
    ensure_heap(env,3);
    return erts_sint64_to_big(i, &env->hp);
#endif
}

ERL_NIF_TERM enif_make_ulong(ErlNifEnv* env, unsigned long i)
{
    if (IS_USMALL(0,i)) {
	return make_small(i);
    }
#if SIZEOF_LONG == ERTS_SIZEOF_ETERM
    return uint_to_big(i,alloc_heap(env,2));
#elif SIZEOF_LONG_LONG ==  ERTS_SIZEOF_ETERM
    return make_small(i);
#elif SIZEOF_LONG == 8
    ensure_heap(env,3);
    return erts_uint64_to_big(i, &env->hp);    
#endif
}

#if HAVE_INT64 && SIZEOF_LONG != 8
ERL_NIF_TERM enif_make_int64(ErlNifEnv* env, ErlNifSInt64 i)
{
    Uint* hp;
    Uint need = 0;
    erts_bld_sint64(NULL, &need, i);
    hp = alloc_heap(env, need);
    return erts_bld_sint64(&hp, NULL, i);
}

ERL_NIF_TERM enif_make_uint64(ErlNifEnv* env, ErlNifUInt64 i)
{
    Uint* hp;
    Uint need = 0;
    erts_bld_uint64(NULL, &need, i);
    hp = alloc_heap(env, need);
    return erts_bld_uint64(&hp, NULL, i);
}
#endif /* HAVE_INT64 && SIZEOF_LONG != 8 */

ERL_NIF_TERM enif_make_double(ErlNifEnv* env, double d)
{
    Eterm* hp;
    FloatDef f;

    if (!erts_isfinite(d))
        return enif_make_badarg(env);
    hp = alloc_heap(env,FLOAT_SIZE_OBJECT);
    f.fd = d;
    PUT_DOUBLE(f, hp);
    return make_float(hp);
}

ERL_NIF_TERM enif_make_atom(ErlNifEnv* env, const char* name)
{
    return enif_make_atom_len(env, name, sys_strlen(name));
}

ERL_NIF_TERM enif_make_atom_len(ErlNifEnv* env, const char* name, size_t len)
{
    if (len > MAX_ATOM_CHARACTERS)
        return enif_make_badarg(env);
    return erts_atom_put((byte*)name, len, ERTS_ATOM_ENC_LATIN1, 1);
}

int enif_make_existing_atom(ErlNifEnv* env, const char* name, ERL_NIF_TERM* atom,
			    ErlNifCharEncoding enc)
{
    return enif_make_existing_atom_len(env, name, sys_strlen(name), atom, enc);
}

int enif_make_existing_atom_len(ErlNifEnv* env, const char* name, size_t len,
				ERL_NIF_TERM* atom, ErlNifCharEncoding encoding)
{
    ASSERT(encoding == ERL_NIF_LATIN1);
    if (len > MAX_ATOM_CHARACTERS)
        return 0;
    return erts_atom_get(name, len, atom, ERTS_ATOM_ENC_LATIN1);
}

ERL_NIF_TERM enif_make_tuple(ErlNifEnv* env, unsigned cnt, ...)
{
    Eterm* hp = alloc_heap(env,cnt+1);
    Eterm ret = make_tuple(hp);
    va_list ap;

    *hp++ = make_arityval(cnt);
    va_start(ap,cnt);
    while (cnt--) {
	*hp++ = va_arg(ap,Eterm);	   
    }
    va_end(ap);
    return ret;
}

ERL_NIF_TERM enif_make_tuple_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)
{
    Eterm* hp = alloc_heap(env,cnt+1);
    Eterm ret = make_tuple(hp);
    const Eterm* src = arr;

    *hp++ = make_arityval(cnt);
    while (cnt--) {
	*hp++ = *src++;	   
    }
    return ret;
}

ERL_NIF_TERM enif_make_list_cell(ErlNifEnv* env, Eterm car, Eterm cdr)
{
    Eterm* hp = alloc_heap(env,2);
    Eterm ret = make_list(hp);

    CAR(hp) = car;
    CDR(hp) = cdr;
    return ret;
}

ERL_NIF_TERM enif_make_list(ErlNifEnv* env, unsigned cnt, ...)
{
    if (cnt == 0) {
	return NIL;
    }
    else {
	Eterm* hp = alloc_heap(env,cnt*2);
	Eterm ret = make_list(hp);
	Eterm* last = &ret;
	va_list ap;

	va_start(ap,cnt);
	while (cnt--) {
	    *last = make_list(hp);
	    *hp = va_arg(ap,Eterm);
	    last = ++hp;
	    ++hp;
	}
	va_end(ap);
	*last = NIL;
	return ret;
    }
}

ERL_NIF_TERM enif_make_list_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)
{
    Eterm* hp = alloc_heap(env,cnt*2);
    Eterm ret = make_list(hp);
    Eterm* last = &ret;
    const Eterm* src = arr;

    while (cnt--) {
	*last = make_list(hp);
	*hp = *src++;
	last = ++hp;
	++hp;
    }
    *last = NIL;
    return ret;
}

ERL_NIF_TERM enif_make_string(ErlNifEnv* env, const char* string,
			      ErlNifCharEncoding encoding)
{
    return enif_make_string_len(env, string, sys_strlen(string), encoding);
}

ERL_NIF_TERM enif_make_string_len(ErlNifEnv* env, const char* string,
				  size_t len, ErlNifCharEncoding encoding)
{
    Eterm* hp = alloc_heap(env,len*2);
    ASSERT(encoding == ERL_NIF_LATIN1);
    return erts_bld_string_n(&hp,NULL,string,len);
}

ERL_NIF_TERM enif_make_ref(ErlNifEnv* env)
{
    Eterm* hp = alloc_heap(env, REF_THING_SIZE);
    return erts_make_ref_in_buffer(hp);
}

void enif_system_info(ErlNifSysInfo *sip, size_t si_size)
{
    driver_system_info(sip, si_size);
}

int enif_make_reverse_list(ErlNifEnv* env, ERL_NIF_TERM term, ERL_NIF_TERM *list) {
    Eterm *listptr, ret = NIL, *hp;

    if (is_nil(term)) {
	*list = term;
        return 1;
    }

    ret = NIL;

    while (is_not_nil(term)) {
	if (is_not_list(term)) {
	    return 0;
	}
	hp = alloc_heap(env, 2);
	listptr = list_val(term);
	ret = CONS(hp, CAR(listptr), ret);
	term = CDR(listptr);
    }
    *list = ret;
    return 1;
}


ErlNifMutex* enif_mutex_create(char *name) { return erl_drv_mutex_create(name); }
void enif_mutex_destroy(ErlNifMutex *mtx) {  erl_drv_mutex_destroy(mtx); }
int enif_mutex_trylock(ErlNifMutex *mtx) { return erl_drv_mutex_trylock(mtx); }
void enif_mutex_lock(ErlNifMutex *mtx) { erl_drv_mutex_lock(mtx); }
void enif_mutex_unlock(ErlNifMutex *mtx) { erl_drv_mutex_unlock(mtx); }
ErlNifCond* enif_cond_create(char *name) { return erl_drv_cond_create(name); }
void enif_cond_destroy(ErlNifCond *cnd) { erl_drv_cond_destroy(cnd); }
void enif_cond_signal(ErlNifCond *cnd) { erl_drv_cond_signal(cnd); }
void enif_cond_broadcast(ErlNifCond *cnd) { erl_drv_cond_broadcast(cnd); }
void enif_cond_wait(ErlNifCond *cnd, ErlNifMutex *mtx) { erl_drv_cond_wait(cnd,mtx); }
ErlNifRWLock* enif_rwlock_create(char *name) { return erl_drv_rwlock_create(name); }
void enif_rwlock_destroy(ErlNifRWLock *rwlck) { erl_drv_rwlock_destroy(rwlck); }
int enif_rwlock_tryrlock(ErlNifRWLock *rwlck) { return erl_drv_rwlock_tryrlock(rwlck); }
void enif_rwlock_rlock(ErlNifRWLock *rwlck) { erl_drv_rwlock_rlock(rwlck); }
void enif_rwlock_runlock(ErlNifRWLock *rwlck) { erl_drv_rwlock_runlock(rwlck); }
int enif_rwlock_tryrwlock(ErlNifRWLock *rwlck) { return erl_drv_rwlock_tryrwlock(rwlck); }
void enif_rwlock_rwlock(ErlNifRWLock *rwlck) { erl_drv_rwlock_rwlock(rwlck); }
void enif_rwlock_rwunlock(ErlNifRWLock *rwlck) { erl_drv_rwlock_rwunlock(rwlck); }
int enif_tsd_key_create(char *name, ErlNifTSDKey *key) { return erl_drv_tsd_key_create(name,key); }
void enif_tsd_key_destroy(ErlNifTSDKey key) { erl_drv_tsd_key_destroy(key); }
void enif_tsd_set(ErlNifTSDKey key, void *data) { erl_drv_tsd_set(key,data); }
void* enif_tsd_get(ErlNifTSDKey key) { return erl_drv_tsd_get(key); }
ErlNifThreadOpts* enif_thread_opts_create(char *name) { return (ErlNifThreadOpts*) erl_drv_thread_opts_create(name); }
void enif_thread_opts_destroy(ErlNifThreadOpts *opts) { erl_drv_thread_opts_destroy((ErlDrvThreadOpts*)opts); }
int enif_thread_create(char *name, ErlNifTid *tid, void* (*func)(void *),
		       void *args, ErlNifThreadOpts *opts) {
    return erl_drv_thread_create(name,tid,func,args,(ErlDrvThreadOpts*)opts);
}
ErlNifTid enif_thread_self(void) { return erl_drv_thread_self(); }
int enif_equal_tids(ErlNifTid tid1, ErlNifTid tid2) { return erl_drv_equal_tids(tid1,tid2); }
void enif_thread_exit(void *resp) { erl_drv_thread_exit(resp); }
int enif_thread_join(ErlNifTid tid, void **respp) { return erl_drv_thread_join(tid,respp); }
int enif_getenv(const char *key, char *value, size_t *value_size) { return erl_drv_getenv(key, value, value_size); }

ErlNifTime enif_monotonic_time(ErlNifTimeUnit time_unit)
{
    return (ErlNifTime) erts_napi_monotonic_time((int) time_unit);
}

ErlNifTime enif_time_offset(ErlNifTimeUnit time_unit)
{
    return (ErlNifTime) erts_napi_time_offset((int) time_unit);
}

ErlNifTime
enif_convert_time_unit(ErlNifTime val,
		       ErlNifTimeUnit from,
		       ErlNifTimeUnit to)
{
    return (ErlNifTime) erts_napi_convert_time_unit((ErtsMonotonicTime) val,
						    (int) from,
						    (int) to);
}

int enif_fprintf(void* filep, const char* format, ...) 
{ 
    int ret;
    va_list arglist;
    va_start(arglist, format);
    ret = erts_vfprintf((FILE*)filep, format, arglist);
    va_end(arglist);
    return ret;
}    

/***********************************************************
 **       Memory managed (GC'ed) "resource" objects       **
 ***********************************************************/


struct enif_resource_type_t
{
    struct enif_resource_type_t* next;   /* list of all resource types */
    struct enif_resource_type_t* prev;    
    struct erl_module_nif* owner;  /* that created this type and thus implements the destructor*/
    ErlNifResourceDtor* dtor;      /* user destructor function */
    erts_refc_t refc;  /* num of resources of this type (HOTSPOT warning)
                          +1 for active erl_module_nif */
    Eterm module;
    Eterm name;
};

/* dummy node in circular list */
struct enif_resource_type_t resource_type_list; 

typedef struct enif_resource_t
{
    struct enif_resource_type_t* type;
#ifdef DEBUG
    erts_refc_t nif_refc;
# ifdef ARCH_32
    byte align__[4];
# endif
#endif

    char data[1];
}ErlNifResource;

#define SIZEOF_ErlNifResource(SIZE) (offsetof(ErlNifResource,data) + (SIZE))
#define DATA_TO_RESOURCE(PTR) ((ErlNifResource*)((char*)(PTR) - offsetof(ErlNifResource,data)))

static ErlNifResourceType* find_resource_type(Eterm module, Eterm name)
{
    ErlNifResourceType* type;
    for (type = resource_type_list.next;
	 type != &resource_type_list;
	 type = type->next) {

	if (type->module == module && type->name == name) {
	    return type;
	}
    }
    return NULL;
}

#define in_area(ptr,start,nbytes) \
    ((UWord)((char*)(ptr) - (char*)(start)) < (nbytes))


static void close_lib(struct erl_module_nif* lib)
{
    ASSERT(lib != NULL);
    ASSERT(lib->handle != NULL);
    ASSERT(erts_refc_read(&lib->rt_dtor_cnt,0) == 0);

    if (lib->entry != NULL && lib->entry->unload != NULL) {
	ErlNifEnv env;
	pre_nif_noproc(&env, lib);
	lib->entry->unload(&env, lib->priv_data);
	post_nif_noproc(&env);
    }
    if (!erts_is_static_nif(lib->handle))
      erts_sys_ddll_close(lib->handle);
    lib->handle = NULL;
}

static void steal_resource_type(ErlNifResourceType* type)
{
    struct erl_module_nif* lib = type->owner;

    if (type->dtor != NULL
	&& erts_refc_dectest(&lib->rt_dtor_cnt, 0) == 0
	&& lib->mod == NULL) {
	/* last type with destructor gone, close orphan lib */

	close_lib(lib);
    }
    if (erts_refc_dectest(&lib->rt_cnt, 0) == 0
	&& lib->mod == NULL) {
	erts_free(ERTS_ALC_T_NIF, lib);
    }
}

/* The opened_rt_list is used by enif_open_resource_type()
 * in order to rollback "creates" and "take-overs" in case the load fails.
 */
struct opened_resource_type
{
    struct opened_resource_type* next;

    ErlNifResourceFlags op;
    ErlNifResourceType* type;
    ErlNifResourceDtor* new_dtor;
};
static struct opened_resource_type* opened_rt_list = NULL;

ErlNifResourceType*
enif_open_resource_type(ErlNifEnv* env,
			const char* module_str, 
			const char* name_str, 
			ErlNifResourceDtor* dtor,
			ErlNifResourceFlags flags,
			ErlNifResourceFlags* tried)
{
    ErlNifResourceType* type = NULL;
    ErlNifResourceFlags op = flags;
    Eterm module_am, name_am;

    ASSERT(erts_smp_thr_progress_is_blocking());
    ASSERT(module_str == NULL); /* for now... */
    module_am = make_atom(env->mod_nif->mod->module);
    name_am = enif_make_atom(env, name_str);

    type = find_resource_type(module_am, name_am);
    if (type == NULL) {
	if (flags & ERL_NIF_RT_CREATE) {
	    type = erts_alloc(ERTS_ALC_T_NIF,
			      sizeof(struct enif_resource_type_t));
	    type->module = module_am;
	    type->name = name_am;
	    erts_refc_init(&type->refc, 1);
	    op = ERL_NIF_RT_CREATE;
	#ifdef DEBUG
	    type->dtor = (void*)1;
	    type->owner = (void*)2;
	    type->prev = (void*)3;
	    type->next = (void*)4;
	#endif
	}
    }
    else {
	if (flags & ERL_NIF_RT_TAKEOVER) {
	    op = ERL_NIF_RT_TAKEOVER;
	}
	else {
	    type = NULL;
	}
    }
    if (type != NULL) {
	struct opened_resource_type* ort = erts_alloc(ERTS_ALC_T_TMP,
						sizeof(struct opened_resource_type));
	ort->op = op;
	ort->type = type;
	ort->new_dtor = dtor;
	ort->next = opened_rt_list;
	opened_rt_list = ort;
    }
    if (tried != NULL) {
	*tried = op;
    }
    return type;
}

static void commit_opened_resource_types(struct erl_module_nif* lib)
{
    while (opened_rt_list) {
	struct opened_resource_type* ort = opened_rt_list;

	ErlNifResourceType* type = ort->type;

	if (ort->op == ERL_NIF_RT_CREATE) {
	    type->prev = &resource_type_list;
	    type->next = resource_type_list.next;
	    type->next->prev = type;
	    type->prev->next = type;
	}
	else { /* ERL_NIF_RT_TAKEOVER */
	    steal_resource_type(type);
	}

	type->owner = lib;
	type->dtor = ort->new_dtor;

	if (type->dtor != NULL) {
	    erts_refc_inc(&lib->rt_dtor_cnt, 1);
	}
	erts_refc_inc(&lib->rt_cnt, 1);

	opened_rt_list = ort->next;
	erts_free(ERTS_ALC_T_TMP, ort);
    }
}

static void rollback_opened_resource_types(void)
{
    while (opened_rt_list) {
	struct opened_resource_type* ort = opened_rt_list;

	if (ort->op == ERL_NIF_RT_CREATE) {
	    erts_free(ERTS_ALC_T_NIF, ort->type);
	}

	opened_rt_list = ort->next;
	erts_free(ERTS_ALC_T_TMP, ort);
    }
}


static void nif_resource_dtor(Binary* bin)
{
    ErlNifResource* resource = (ErlNifResource*) ERTS_MAGIC_BIN_UNALIGNED_DATA(bin);
    ErlNifResourceType* type = resource->type;
    ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);

    if (type->dtor != NULL) {
	ErlNifEnv env;
	pre_nif_noproc(&env, type->owner);
	type->dtor(&env,resource->data);
	post_nif_noproc(&env);
    }
    if (erts_refc_dectest(&type->refc, 0) == 0) {
	ASSERT(type->next == NULL);
	ASSERT(type->owner != NULL);
	ASSERT(type->owner->mod == NULL);
	steal_resource_type(type);
	erts_free(ERTS_ALC_T_NIF, type);
    }
}

void* enif_alloc_resource(ErlNifResourceType* type, size_t size)
{
    Binary* bin = erts_create_magic_binary_x(SIZEOF_ErlNifResource(size),
                                             &nif_resource_dtor,
                                             1); /* unaligned */
    ErlNifResource* resource = ERTS_MAGIC_BIN_UNALIGNED_DATA(bin);

    ASSERT(type->owner && type->next && type->prev); /* not allowed in load/upgrade */
    resource->type = type;
    erts_refc_inc(&bin->refc, 1);
#ifdef DEBUG
    erts_refc_init(&resource->nif_refc, 1);
#endif
    erts_refc_inc(&resource->type->refc, 2);
    return resource->data;
}

void enif_release_resource(void* obj)
{
    ErlNifResource* resource = DATA_TO_RESOURCE(obj);
    ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);

    ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);
#ifdef DEBUG
    erts_refc_dec(&resource->nif_refc, 0);
#endif
    if (erts_refc_dectest(&bin->binary.refc, 0) == 0) {
	erts_bin_free(&bin->binary);
    }
}

void enif_keep_resource(void* obj)
{
    ErlNifResource* resource = DATA_TO_RESOURCE(obj);
    ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);

    ASSERT(ERTS_MAGIC_BIN_DESTRUCTOR(bin) == &nif_resource_dtor);
#ifdef DEBUG
    erts_refc_inc(&resource->nif_refc, 1);
#endif
    erts_refc_inc(&bin->binary.refc, 2);
}

ERL_NIF_TERM enif_make_resource(ErlNifEnv* env, void* obj)
{
    ErlNifResource* resource = DATA_TO_RESOURCE(obj);
    ErtsBinary* bin = ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource);
    Eterm* hp = alloc_heap(env,PROC_BIN_SIZE);
    return erts_mk_magic_binary_term(&hp, &MSO(env->proc), &bin->binary);
}

ERL_NIF_TERM enif_make_resource_binary(ErlNifEnv* env, void* obj,
				       const void* data, size_t size)
{
    Eterm bin = enif_make_resource(env, obj);
    ProcBin* pb = (ProcBin*) binary_val(bin);
    pb->bytes = (byte*) data;
    pb->size = size;
    return bin;
}

int enif_get_resource(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifResourceType* type,
		      void** objp)
{
    ProcBin* pb;
    Binary* mbin;
    ErlNifResource* resource;
    if (!ERTS_TERM_IS_MAGIC_BINARY(term)) {
	return 0;
    }
    pb = (ProcBin*) binary_val(term);
    /*if (pb->size != 0) {	
	return 0; / * Or should we allow "resource binaries" as handles? * /
    }*/
    mbin = pb->val;
    resource = (ErlNifResource*) ERTS_MAGIC_BIN_UNALIGNED_DATA(mbin);
    if (ERTS_MAGIC_BIN_DESTRUCTOR(mbin) != &nif_resource_dtor
	|| resource->type != type) {	
	return 0;
    }
    *objp = resource->data;
    return 1;
}

size_t enif_sizeof_resource(void* obj)
{
    ErlNifResource* resource = DATA_TO_RESOURCE(obj);
    Binary* bin = &ERTS_MAGIC_BIN_FROM_UNALIGNED_DATA(resource)->binary;
    return ERTS_MAGIC_BIN_UNALIGNED_DATA_SIZE(bin) - offsetof(ErlNifResource,data);
}


void* enif_dlopen(const char* lib,
		  void (*err_handler)(void*,const char*), void* err_arg)
{
    ErtsSysDdllError errdesc = ERTS_SYS_DDLL_ERROR_INIT;
    void* handle;
    void* init_func;
    if (erts_sys_ddll_open(lib, &handle, &errdesc) == ERL_DE_NO_ERROR) {
	if (erts_sys_ddll_load_nif_init(handle, &init_func, &errdesc) == ERL_DE_NO_ERROR) {
	    erts_sys_ddll_call_nif_init(init_func);
	}
    }
    else {
	if (err_handler != NULL) {
	    (*err_handler)(err_arg, errdesc.str);
	}
	handle = NULL;
    }
    erts_sys_ddll_free_error(&errdesc);
    return handle;
}

void* enif_dlsym(void* handle, const char* symbol,
		 void (*err_handler)(void*,const char*), void* err_arg)
{
    ErtsSysDdllError errdesc = ERTS_SYS_DDLL_ERROR_INIT;
    void* ret;
    if (erts_sys_ddll_sym2(handle, symbol, &ret, &errdesc) != ERL_DE_NO_ERROR) {
	if (err_handler != NULL) {
	    (*err_handler)(err_arg, errdesc.str);
	}
	erts_sys_ddll_free_error(&errdesc);
	return NULL;
    }
    return ret;
}

int enif_consume_timeslice(ErlNifEnv* env, int percent)
{
    Sint reds;

    ASSERT(is_proc_bound(env) && percent >= 1 && percent <= 100);
    if (percent < 1) percent = 1;
    else if (percent > 100) percent = 100;

    reds = ((CONTEXT_REDS+99) / 100) * percent;
    ASSERT(reds > 0 && reds <= CONTEXT_REDS);
    BUMP_REDS(env->proc, reds);
    return ERTS_BIF_REDS_LEFT(env->proc) == 0;
}

/*
 * NIF exports need a few more items than the Export struct provides,
 * including the erl_module_nif* and a NIF function pointer, so the
 * NifExport below adds those. The Export member must be first in the
 * struct. The saved_mfa, exception_thrown, saved_argc, rootset_extra, and
 * rootset members are used to track the MFA, any pending exception, and
 * arguments of the top NIF in case a chain of one or more
 * enif_schedule_nif() calls results in an exception, since in that case
 * the original MFA and registers have to be restored before returning to
 * Erlang to ensure stacktrace information associated with the exception is
 * correct.
 */
typedef ERL_NIF_TERM (*NativeFunPtr)(ErlNifEnv*, int, const ERL_NIF_TERM[]);

typedef struct {
    Export exp;
    struct erl_module_nif* m;
    NativeFunPtr fp;
    Eterm saved_mfa[3];
    int exception_thrown;
    int saved_argc;
    int rootset_extra;
    Eterm rootset[1];
} NifExport;

/*
 * If a process has saved arguments, they need to be part of the GC
 * rootset. The function below is called from setup_rootset() in
 * erl_gc.c. This function is declared in erl_process.h. Any exception term
 * saved in the NifExport is also made part of the GC rootset here; it
 * always resides in rootset[0].
 */
int
erts_setup_nif_gc(Process* proc, Eterm** objv, int* nobj)
{
    NifExport* ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    int gc = ep && (ep->saved_argc > 0 || ep->rootset[0] != NIL);

    if (gc) {
	*objv = ep->rootset;
	*nobj = 1 + ep->saved_argc;
    }
    return gc;
}

/*
 * Allocate a NifExport and set it in proc specific data
 */
static NifExport*
allocate_nif_sched_data(Process* proc, int argc)
{
    NifExport* ep;
    size_t total;
    int i;

    total = sizeof(NifExport) + argc*sizeof(Eterm);
    ep = erts_alloc(ERTS_ALC_T_NIF_TRAP_EXPORT, total);
    sys_memset((void*) ep, 0, total);
    ep->rootset_extra = argc;
    ep->rootset[0] = NIL;
    for (i=0; i<ERTS_NUM_CODE_IX; i++) {
	ep->exp.addressv[i] = &ep->exp.code[3];
    }
    ep->exp.code[3] = (BeamInstr) em_call_nif;
    (void) ERTS_PROC_SET_NIF_TRAP_EXPORT(proc, ERTS_PROC_LOCK_MAIN, ep);
    return ep;
}

static ERTS_INLINE void
destroy_nif_export(NifExport *nif_export)
{
    erts_free(ERTS_ALC_T_NIF_TRAP_EXPORT, (void *) nif_export);
}

void
erts_destroy_nif_export(void *nif_export)
{
    destroy_nif_export((NifExport *) nif_export);
}

/*
 * Initialize a NifExport struct. Create it if needed and store it in the
 * proc. The direct_fp function is what will be invoked by op_call_nif, and
 * the indirect_fp function, if not NULL, is what the direct_fp function
 * will call. If the allocated NifExport isn't enough to hold all of argv,
 * allocate a larger one. Save MFA and registers only if the need_save
 * parameter is true.
 */
static ERL_NIF_TERM
init_nif_sched_data(ErlNifEnv* env, NativeFunPtr direct_fp, NativeFunPtr indirect_fp,
		    int need_save, int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;
    NifExport* ep;
    int i;

    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    if (!ep)
	ep = allocate_nif_sched_data(proc, argc);
    else if (need_save && ep->rootset_extra < argc) {
	NifExport* new_ep = allocate_nif_sched_data(proc, argc);
	destroy_nif_export(ep);
	ep = new_ep;
    }
    if (env->exception_thrown) {
	ep->exception_thrown = 1;
	ep->rootset[0] = env->proc->fvalue;
    } else {
	ep->exception_thrown = 0;
	ep->rootset[0] = NIL;
    }
    ERTS_VBUMP_ALL_REDS(proc);
    for (i = 0; i < argc; i++) {
	if (need_save)
	    ep->rootset[i+1] = reg[i];
	reg[i] = (Eterm) argv[i];
    }
    if (need_save) {
	ep->saved_mfa[0] = proc->current[0];
	ep->saved_mfa[1] = proc->current[1];
	ep->saved_mfa[2] = proc->current[2];
	ep->saved_argc = argc;
    }
    proc->i = (BeamInstr*) ep->exp.addressv[0];
    ep->exp.code[0] = (BeamInstr) proc->current[0];
    ep->exp.code[1] = (BeamInstr) proc->current[1];
    ep->exp.code[2] = argc;
    ep->exp.code[4] = (BeamInstr) direct_fp;
    ep->m = env->mod_nif;
    ep->fp = indirect_fp;
    proc->freason = TRAP;
    proc->arity = argc;
    return THE_NON_VALUE;
}

/*
 * Restore saved MFA and registers. Registers are restored only when the
 * exception flag is true.
 */
static void
restore_nif_mfa(Process* proc, NifExport* ep, int exception)
{
    int i;
    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;

    proc->current[0] = ep->saved_mfa[0];
    proc->current[1] = ep->saved_mfa[1];
    proc->current[2] = ep->saved_mfa[2];
    if (exception)
	for (i = 0; i < ep->saved_argc; i++)
	    reg[i] = ep->rootset[i+1];
    ep->saved_argc = 0;
    ep->saved_mfa[0] = THE_NON_VALUE;
}

#ifdef ERTS_DIRTY_SCHEDULERS

/*
 * Finalize a dirty NIF call. This function is scheduled to cause the VM to
 * switch the process off a dirty scheduler thread and back onto a regular
 * scheduler thread, and then return the result from the dirty NIF. It also
 * restores the original NIF MFA when necessary based on the value of
 * ep->fp set by execute_dirty_nif via init_nif_sched_data -- non-NULL
 * means restore, NULL means do not restore.
 */
static ERL_NIF_TERM
dirty_nif_finalizer(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    NifExport* ep;

    ASSERT(argc == 1);
    ASSERT(!ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    ASSERT(!ep->exception_thrown);
    if (ep->fp)
	restore_nif_mfa(proc, ep, 0);
    return argv[0];
}

/* Finalize a dirty NIF call that raised an exception.  Otherwise same as
 * the dirty_nif_finalizer() function.
 */
static ERL_NIF_TERM
dirty_nif_exception(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    NifExport* ep;

    ASSERT(!ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    ASSERT(ep->exception_thrown);
    if (ep->fp)
	restore_nif_mfa(proc, ep, 1);
    return enif_raise_exception(env, ep->rootset[0]);
}

/*
 * Dirty NIF execution wrapper function. Invoke an application's dirty NIF,
 * then check the result and schedule the appropriate finalizer function
 * where needed. Also restore the original NIF MFA when appropriate.
 */
static ERL_NIF_TERM
execute_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
    NifExport* ep;
    ERL_NIF_TERM result;

    ASSERT(ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));

    /*
     * Set ep->fp to NULL before the native call so we know later whether it scheduled another NIF for execution
     */
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    ep->fp = NULL;
    result = (*fp)(env, argc, argv);
    erts_smp_atomic32_read_band_mb(&proc->state,
				   ~(ERTS_PSFLG_DIRTY_CPU_PROC
				     |ERTS_PSFLG_DIRTY_IO_PROC
				     |ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q
				     |ERTS_PSFLG_DIRTY_IO_PROC_IN_Q));
    if (erts_refc_dectest(&env->mod_nif->rt_dtor_cnt, 0) == 0 && env->mod_nif->mod == NULL)
	close_lib(env->mod_nif);
    /*
     * If no more NIFs were scheduled by the native call via
     * enif_schedule_nif(), then ep->fp will still be NULL as set above, in
     * which case we need to restore the original NIF calling
     * context. Reuse fp essentially as a boolean for this, passing it to
     * init_nif_sched_data below. Both dirty_nif_exception and
     * dirty_nif_finalizer then check ep->fp to decide whether or not to
     * restore the original calling context.
     */
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    if (ep->fp)
	fp = NULL;
    if (is_non_value(result) || env->exception_thrown) {
	if (proc->freason != TRAP) {
	    return init_nif_sched_data(env, dirty_nif_exception, fp, 0, argc, argv);
	} else {
	    if (ep->fp == NULL)
		restore_nif_mfa(proc, ep, 1);
	    return THE_NON_VALUE;
	}
    }
    else
	return init_nif_sched_data(env, dirty_nif_finalizer, fp, 0, 1, &result);
}

/*
 * Dirty NIF scheduling wrapper function. Schedule a dirty NIF to execute
 * via the execute_dirty_nif() wrapper function. The dirty scheduler thread
 * type (CPU or I/O) is indicated in flags parameter.
 */
static ERTS_INLINE ERL_NIF_TERM
schedule_dirty_nif(ErlNifEnv* env, int flags, int argc, const ERL_NIF_TERM argv[])
{
    erts_aint32_t state, n, a;
    Process* proc = env->proc;
    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
    NifExport* ep;
    int need_save;

    ASSERT(flags==ERL_NIF_DIRTY_JOB_IO_BOUND || flags==ERL_NIF_DIRTY_JOB_CPU_BOUND);

    a = erts_smp_atomic32_read_acqb(&proc->state);
    while (1) {
	n = state = a;
	/*
	 * clear any current dirty flags and dirty queue indicators,
	 * in case the application is shifting a job from one type
	 * of dirty scheduler to the other
	 */
	n &= ~(ERTS_PSFLG_DIRTY_CPU_PROC|ERTS_PSFLG_DIRTY_IO_PROC
	       |ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q|ERTS_PSFLG_DIRTY_IO_PROC_IN_Q);
	if (flags == ERL_NIF_DIRTY_JOB_CPU_BOUND)
	    n |= ERTS_PSFLG_DIRTY_CPU_PROC;
	else
	    n |= ERTS_PSFLG_DIRTY_IO_PROC;
	a = erts_smp_atomic32_cmpxchg_mb(&proc->state, n, state);
	if (a == state)
	    break;
    }
    erts_refc_inc(&env->mod_nif->rt_dtor_cnt, 1);
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    need_save = (ep == NULL || is_non_value(ep->saved_mfa[0]));
    return init_nif_sched_data(env, execute_dirty_nif, fp, need_save, argc, argv);
}

static ERL_NIF_TERM
schedule_dirty_io_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    return schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_IO_BOUND, argc, argv);
}

static ERL_NIF_TERM
schedule_dirty_cpu_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    return schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_CPU_BOUND, argc, argv);
}

#endif /* ERTS_DIRTY_SCHEDULERS */

/*
 * NIF execution wrapper used by enif_schedule_nif() for regular NIFs. It
 * calls the actual NIF, restores original NIF MFA if necessary, and
 * then returns the NIF result.
 */
static ERL_NIF_TERM
execute_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
    NifExport* ep;
    ERL_NIF_TERM result;

    ASSERT(!env->exception_thrown);
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    ep->fp = NULL;
    result = (*fp)(env, argc, argv);
    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    /*
     * If no NIFs were scheduled by the native call via
     * enif_schedule_nif(), then ep->fp will still be NULL as set above, in
     * which case we need to restore the original NIF MFA.
     */
    if (ep->fp == NULL)
	restore_nif_mfa(proc, ep, env->exception_thrown);
    return result;
}

ERL_NIF_TERM
enif_schedule_nif(ErlNifEnv* env, const char* fun_name, int flags,
		  ERL_NIF_TERM (*fp)(ErlNifEnv*, int, const ERL_NIF_TERM[]),
		  int argc, const ERL_NIF_TERM argv[])
{
    Process* proc = env->proc;
    NifExport* ep;
    ERL_NIF_TERM fun_name_atom, result;
    int need_save;

    if (argc > MAX_ARG)
	return enif_make_badarg(env);
    fun_name_atom = enif_make_atom(env, fun_name);
    if (enif_is_exception(env, fun_name_atom))
	return fun_name_atom;

    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    need_save = (ep == NULL || is_non_value(ep->saved_mfa[0]));

    if (flags) {
#ifdef ERTS_DIRTY_SCHEDULERS
	NativeFunPtr sched_fun;
	int chkflgs = (flags & (ERL_NIF_DIRTY_JOB_IO_BOUND|ERL_NIF_DIRTY_JOB_CPU_BOUND));
	if (chkflgs == ERL_NIF_DIRTY_JOB_IO_BOUND)
	    sched_fun = schedule_dirty_io_nif;
	else if (chkflgs == ERL_NIF_DIRTY_JOB_CPU_BOUND)
	    sched_fun = schedule_dirty_cpu_nif;
	else
	    return enif_make_badarg(env);
	result = init_nif_sched_data(env, sched_fun, fp, need_save, argc, argv);
#else
	return enif_make_badarg(env);
#endif
    }
    else
	result = init_nif_sched_data(env, execute_nif, fp, need_save, argc, argv);

    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
    ASSERT(ep);
    ep->exp.code[1] = (BeamInstr) fun_name_atom;
    return result;
}

#ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT

int
enif_is_on_dirty_scheduler(ErlNifEnv* env)
{
    return ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data);
}

#endif /* ERL_NIF_DIRTY_SCHEDULER_SUPPORT */

/* Maps */

int enif_is_map(ErlNifEnv* env, ERL_NIF_TERM term)
{
    return is_map(term);
}

int enif_get_map_size(ErlNifEnv* env, ERL_NIF_TERM term, size_t *size)
{
    if (is_flatmap(term)) {
	flatmap_t *mp;
	mp    = (flatmap_t*)flatmap_val(term);
	*size = flatmap_get_size(mp);
	return 1;
    }
    else if (is_hashmap(term)) {
        *size = hashmap_size(term);
        return 1;
    }
    return 0;
}

ERL_NIF_TERM enif_make_new_map(ErlNifEnv* env)
{
    Eterm* hp = alloc_heap(env,MAP_HEADER_FLATMAP_SZ+1);
    Eterm tup;
    flatmap_t *mp;

    tup   = make_tuple(hp);
    *hp++ = make_arityval(0);
    mp    = (flatmap_t*)hp;
    mp->thing_word = MAP_HEADER_FLATMAP;
    mp->size = 0;
    mp->keys = tup;

    return make_flatmap(mp);
}

int enif_make_map_put(ErlNifEnv* env,
	              Eterm map_in,
		      Eterm key,
		      Eterm value,
		      Eterm *map_out)
{
    if (!is_map(map_in)) {
	return 0;
    }
    flush_env(env);
    *map_out = erts_maps_put(env->proc, key, value, map_in);
    cache_env(env);
    return 1;
}

int enif_get_map_value(ErlNifEnv* env,
	               Eterm map,
		       Eterm key,
		       Eterm *value)
{
    const Eterm *ret;
    if (!is_map(map)) {
	return 0;
    }
    ret = erts_maps_get(key, map);
    if (ret) {
        *value = *ret;
        return 1;
    }
    return 0;
}

int enif_make_map_update(ErlNifEnv* env,
	                 Eterm map_in,
			 Eterm key,
			 Eterm value,
			 Eterm *map_out)
{
    int res;
    if (!is_map(map_in)) {
	return 0;
    }

    flush_env(env);
    res = erts_maps_update(env->proc, key, value, map_in, map_out);
    cache_env(env);
    return res;
}

int enif_make_map_remove(ErlNifEnv* env,
	                 Eterm map_in,
			 Eterm key,
			 Eterm *map_out)
{
    int res;
    if (!is_map(map_in)) {
	return 0;
    }
    flush_env(env);
    res = erts_maps_remove(env->proc, key, map_in, map_out);
    cache_env(env);
    return res;
}

int enif_map_iterator_create(ErlNifEnv *env,
	                     Eterm map,
			     ErlNifMapIterator *iter,
			     ErlNifMapIteratorEntry entry)
{
    if (is_flatmap(map)) {
	flatmap_t *mp = (flatmap_t*)flatmap_val(map);
	size_t offset;

	switch (entry) {
	    case ERL_NIF_MAP_ITERATOR_FIRST: offset = 0; break;
	    case ERL_NIF_MAP_ITERATOR_LAST: offset = flatmap_get_size(mp) - 1; break;
	    default: goto error;
	}

	/* empty maps are ok but will leave the iterator
	 * in bad shape.
	 */

	iter->map     = map;
	iter->u.flat.ks = ((Eterm *)flatmap_get_keys(mp)) + offset;
	iter->u.flat.vs = ((Eterm *)flatmap_get_values(mp)) + offset;
	iter->size    = flatmap_get_size(mp);
	iter->idx     = offset + 1;

	return 1;
    }
    else if (is_hashmap(map)) {
        iter->map = map;
        iter->size = hashmap_size(map);
        iter->u.hash.wstack = erts_alloc(ERTS_ALC_T_NIF, sizeof(ErtsDynamicWStack));
        WSTACK_INIT(iter->u.hash.wstack, ERTS_ALC_T_NIF);

        switch (entry) {
	    case ERL_NIF_MAP_ITERATOR_FIRST:
                iter->idx = 1;
                hashmap_iterator_init(&iter->u.hash.wstack->ws, map, 0);
                iter->u.hash.kv = hashmap_iterator_next(&iter->u.hash.wstack->ws);
                break;
	    case ERL_NIF_MAP_ITERATOR_LAST:
                iter->idx = hashmap_size(map);
                hashmap_iterator_init(&iter->u.hash.wstack->ws, map, 1);
                iter->u.hash.kv = hashmap_iterator_prev(&iter->u.hash.wstack->ws);
                break;
	    default:
                goto error;
	}
        ASSERT(!!iter->u.hash.kv == (iter->idx >= 1 &&
                                     iter->idx <= iter->size));
        return 1;
    }
error:
#ifdef DEBUG
    iter->map = THE_NON_VALUE;
#endif
    return 0;
}

void enif_map_iterator_destroy(ErlNifEnv *env, ErlNifMapIterator *iter)
{
    if (is_hashmap(iter->map)) {
        WSTACK_DESTROY(iter->u.hash.wstack->ws);
        erts_free(ERTS_ALC_T_NIF, iter->u.hash.wstack);
    }
    else
        ASSERT(is_flatmap(iter->map));

#ifdef DEBUG
    iter->map = THE_NON_VALUE;
#endif
}

int enif_map_iterator_is_tail(ErlNifEnv *env, ErlNifMapIterator *iter)
{
    ASSERT(iter);
    if (is_flatmap(iter->map)) {
        ASSERT(iter->idx >= 0);
        ASSERT(iter->idx <= flatmap_get_size(flatmap_val(iter->map)) + 1);
        return (iter->size == 0 || iter->idx > iter->size);
    }
    else {
        ASSERT(is_hashmap(iter->map));
        return iter->idx > iter->size;
    }
}

int enif_map_iterator_is_head(ErlNifEnv *env, ErlNifMapIterator *iter)
{
    ASSERT(iter);
    if (is_flatmap(iter->map)) {
        ASSERT(iter->idx >= 0);
        ASSERT(iter->idx <= flatmap_get_size(flatmap_val(iter->map)) + 1);
        return (iter->size == 0 || iter->idx == 0);
    }
    else {
        ASSERT(is_hashmap(iter->map));
        return iter->idx == 0;
    }
}


int enif_map_iterator_next(ErlNifEnv *env, ErlNifMapIterator *iter)
{
    ASSERT(iter);
    if (is_flatmap(iter->map)) {
        if (iter->idx <= iter->size) {
            iter->idx++;
            iter->u.flat.ks++;
            iter->u.flat.vs++;
        }
        return (iter->idx <= iter->size);
    }
    else {
        ASSERT(is_hashmap(iter->map));

        if (iter->idx <= hashmap_size(iter->map)) {
            if (iter->idx < 1) {
                hashmap_iterator_init(&iter->u.hash.wstack->ws, iter->map, 0);
            }
            iter->u.hash.kv = hashmap_iterator_next(&iter->u.hash.wstack->ws);
            iter->idx++;
            ASSERT(!!iter->u.hash.kv == (iter->idx <= iter->size));
        }
        return iter->idx <= iter->size;
    }
}

int enif_map_iterator_prev(ErlNifEnv *env, ErlNifMapIterator *iter)
{
    ASSERT(iter);
    if (is_flatmap(iter->map)) {
        if (iter->idx > 0) {
            iter->idx--;
            iter->u.flat.ks--;
            iter->u.flat.vs--;
        }
        return iter->idx > 0;
    }
    else {
        ASSERT(is_hashmap(iter->map));

        if (iter->idx > 0) {
            if (iter->idx > iter->size) {
                hashmap_iterator_init(&iter->u.hash.wstack->ws, iter->map, 1);
            }
            iter->u.hash.kv = hashmap_iterator_prev(&iter->u.hash.wstack->ws);
            iter->idx--;
            ASSERT(!!iter->u.hash.kv == (iter->idx > 0));
        }
        return iter->idx > 0;
    }
}

int enif_map_iterator_get_pair(ErlNifEnv *env,
			       ErlNifMapIterator *iter,
			       Eterm *key,
			       Eterm *value)
{
    ASSERT(iter);
    if (is_flatmap(iter->map)) {
        if (iter->idx > 0 && iter->idx <= iter->size) {
            ASSERT(iter->u.flat.ks >= flatmap_get_keys(flatmap_val(iter->map)) &&
                   iter->u.flat.ks  < (flatmap_get_keys(flatmap_val(iter->map)) + flatmap_get_size(flatmap_val(iter->map))));
            ASSERT(iter->u.flat.vs >= flatmap_get_values(flatmap_val(iter->map)) &&
                   iter->u.flat.vs  < (flatmap_get_values(flatmap_val(iter->map)) + flatmap_get_size(flatmap_val(iter->map))));
            *key   = *(iter->u.flat.ks);
            *value = *(iter->u.flat.vs);
            return 1;
        }
    }
    else {
        ASSERT(is_hashmap(iter->map));
        if (iter->idx > 0 && iter->idx <= iter->size) {
            *key   = CAR(iter->u.hash.kv);
            *value = CDR(iter->u.hash.kv);
            return 1;
        }
    }
    return 0;
}

/***************************************************************************
 **                              load_nif/2                               **
 ***************************************************************************/


static BeamInstr** get_func_pp(BeamInstr* mod_code, Eterm f_atom, unsigned arity)
{
    int n = (int) mod_code[MI_NUM_FUNCTIONS];
    int j;
    for (j = 0; j < n; ++j) {
	BeamInstr* code_ptr = (BeamInstr*) mod_code[MI_FUNCTIONS+j];
	ASSERT(code_ptr[0] == (BeamInstr) BeamOp(op_i_func_info_IaaI));
	if (f_atom == ((Eterm) code_ptr[3])
	    && arity == ((unsigned) code_ptr[4])) {

	    return (BeamInstr**) &mod_code[MI_FUNCTIONS+j];
	}
    }
    return NULL;
}

static Eterm mkatom(const char *str)
{
    return am_atom_put(str, sys_strlen(str));
}

static struct tainted_module_t
{
    struct tainted_module_t* next;
    Eterm module_atom;
}*first_tainted_module = NULL;

static void add_taint(Eterm mod_atom)
{
    struct tainted_module_t* t;
    for (t=first_tainted_module ; t!=NULL; t=t->next) {
	if (t->module_atom == mod_atom) {
	    return;
	}
    }
    t = erts_alloc_fnf(ERTS_ALC_T_TAINT, sizeof(*t));
    if (t != NULL) {
	t->module_atom = mod_atom;
	t->next = first_tainted_module;
	first_tainted_module = t;
    }
}

Eterm erts_nif_taints(Process* p)
{
    struct tainted_module_t* t;
    unsigned cnt = 0;
    Eterm list = NIL;
    Eterm* hp;
    for (t=first_tainted_module ; t!=NULL; t=t->next) {
	cnt++;
    }
    hp = HAlloc(p,cnt*2);
    for (t=first_tainted_module ; t!=NULL; t=t->next) {
	list = CONS(hp, t->module_atom, list);
	hp += 2;
    }
    return list;
}

void erts_print_nif_taints(int to, void* to_arg)
{
    struct tainted_module_t* t;
    const char* delim = "";
    for (t=first_tainted_module ; t!=NULL; t=t->next) {
	const Atom* atom = atom_tab(atom_val(t->module_atom));
	erts_print(to,to_arg,"%s%.*s", delim, atom->len, atom->name);
	delim = ",";
    }
    erts_print(to,to_arg,"\n");
}


static Eterm load_nif_error(Process* p, const char* atom, const char* format, ...)
{
    erts_dsprintf_buf_t* dsbufp = erts_create_tmp_dsbuf(0);
    Eterm ret;
    Eterm* hp;
    Eterm** hpp = NULL;
    Uint sz = 0;
    Uint* szp = &sz;
    va_list arglist;   

    va_start(arglist, format);
    erts_vdsprintf(dsbufp, format, arglist);
    va_end(arglist);
    
    for (;;) {
	Eterm txt = erts_bld_string_n(hpp, &sz, dsbufp->str, dsbufp->str_len);
	ret = erts_bld_tuple(hpp, szp, 2, am_error,
			     erts_bld_tuple(hpp, szp, 2, mkatom(atom), txt));
	if (hpp != NULL) {
	    break;
	}
	hp = HAlloc(p,sz);
	hpp = &hp;
	szp = NULL;
    }
    erts_destroy_tmp_dsbuf(dsbufp);
    return ret;
}

/*
 * The function below is for looping through ErlNifFunc arrays, helping
 * provide backwards compatibility across the version 2.7 change that added
 * the "flags" field to ErlNifFunc.
 */
static ErlNifFunc* next_func(ErlNifEntry* entry, int* incrp, ErlNifFunc* func)
{
    ASSERT(incrp);
    if (!*incrp) {
	if (entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
	    *incrp = sizeof(ErlNifFunc);
	else {
	    /*
	     * ErlNifFuncV1 below is what ErlNifFunc was before the
	     * addition of the flags field for 2.7, and is needed to handle
	     * backward compatibility.
	     */
	    typedef struct {
		const char* name;
		unsigned arity;
		ERL_NIF_TERM (*fptr)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
	    }ErlNifFuncV1;
	    *incrp = sizeof(ErlNifFuncV1);
	}
    }
    return (ErlNifFunc*) ((char*)func + *incrp);
}


BIF_RETTYPE load_nif_2(BIF_ALIST_2)
{
    static const char bad_lib[] = "bad_lib";
    static const char reload[] = "reload";
    static const char upgrade[] = "upgrade";
    char* lib_name = NULL;
    void* handle = NULL;
    void* init_func = NULL;
    ErlNifEntry* entry = NULL;
    ErlNifEnv env;
    int i, err, encoding;
    Module* mod;
    Eterm mod_atom;
    const Atom* mod_atomp;
    Eterm f_atom;
    BeamInstr* caller;
    ErtsSysDdllError errdesc = ERTS_SYS_DDLL_ERROR_INIT;
    Eterm ret = am_ok;
    int veto;
    struct erl_module_nif* lib = NULL;
    int reload_warning = 0;

    encoding = erts_get_native_filename_encoding();
    if (encoding == ERL_FILENAME_WIN_WCHAR) {
        /* Do not convert the lib name to utf-16le yet, do that in win32 specific code */
        /* since lib_name is used in error messages */
        encoding = ERL_FILENAME_UTF8;
    }
    lib_name = erts_convert_filename_to_encoding(BIF_ARG_1, NULL, 0,
                                                 ERTS_ALC_T_TMP, 1, 0, encoding,
						 NULL, 0);
    if (!lib_name) {
	BIF_ERROR(BIF_P, BADARG);
    }

    if (!erts_try_seize_code_write_permission(BIF_P)) {
	erts_free(ERTS_ALC_T_TMP, lib_name);
	ERTS_BIF_YIELD2(bif_export[BIF_load_nif_2],
			BIF_P, BIF_ARG_1, BIF_ARG_2);
    }

    /* Block system (is this the right place to do it?) */
    erts_smp_proc_unlock(BIF_P, ERTS_PROC_LOCK_MAIN);
    erts_smp_thr_progress_block();

    /* Find calling module */
    ASSERT(BIF_P->current != NULL);
    ASSERT(BIF_P->current[0] == am_erlang
	   && BIF_P->current[1] == am_load_nif 
	   && BIF_P->current[2] == 2);
    caller = find_function_from_pc(BIF_P->cp);
    ASSERT(caller != NULL);
    mod_atom = caller[0];
    ASSERT(is_atom(mod_atom));
    mod=erts_get_module(mod_atom, erts_active_code_ix());
    ASSERT(mod != NULL);

    mod_atomp = atom_tab(atom_val(mod_atom));
    init_func = erts_static_nif_get_nif_init((char*)mod_atomp->name, mod_atomp->len);
    if (init_func != NULL)
      handle = init_func;

    if (!in_area(caller, mod->curr.code, mod->curr.code_length)) {
	ASSERT(in_area(caller, mod->old.code, mod->old.code_length));

	ret = load_nif_error(BIF_P, "old_code", "Calling load_nif from old "
			     "module '%T' not allowed", mod_atom);
    }    
    else if (init_func == NULL &&
	     (err=erts_sys_ddll_open(lib_name, &handle, &errdesc)) != ERL_DE_NO_ERROR) {
	const char slogan[] = "Failed to load NIF library";
	if (strstr(errdesc.str, lib_name) != NULL) {
	    ret = load_nif_error(BIF_P, "load_failed", "%s: '%s'", slogan, errdesc.str);
	}
	else {
	    ret = load_nif_error(BIF_P, "load_failed", "%s %s: '%s'", slogan, lib_name, errdesc.str);
	}
    }
    else if (init_func == NULL &&
	     erts_sys_ddll_load_nif_init(handle, &init_func, &errdesc) != ERL_DE_NO_ERROR) {
	ret  = load_nif_error(BIF_P, bad_lib, "Failed to find library init"
			      " function: '%s'", errdesc.str);
	
    }
    else if ((add_taint(mod_atom),
	      (entry = erts_sys_ddll_call_nif_init(init_func)) == NULL)) {
	ret = load_nif_error(BIF_P, bad_lib, "Library init-call unsuccessful");
    }
    else if (entry->major < ERL_NIF_MIN_REQUIRED_MAJOR_VERSION_ON_LOAD
	     || (ERL_NIF_MAJOR_VERSION < entry->major
		 || (ERL_NIF_MAJOR_VERSION == entry->major
		     && ERL_NIF_MINOR_VERSION < entry->minor))
	     || (entry->major==2 && entry->minor == 5)) { /* experimental maps */
	
	ret = load_nif_error(BIF_P, bad_lib, "Library version (%d.%d) not compatible (with %d.%d).",
			     entry->major, entry->minor, ERL_NIF_MAJOR_VERSION, ERL_NIF_MINOR_VERSION);
    }   
    else if (entry->minor >= 1
	     && sys_strcmp(entry->vm_variant, ERL_NIF_VM_VARIANT) != 0) {
	ret = load_nif_error(BIF_P, bad_lib, "Library (%s) not compiled for "
			     "this vm variant (%s).",
			     entry->vm_variant, ERL_NIF_VM_VARIANT);
    }
    else if (!erts_is_atom_str((char*)entry->name, mod_atom, 1)) {
	ret = load_nif_error(BIF_P, bad_lib, "Library module name '%s' does not"
			     " match calling module '%T'", entry->name, mod_atom);
    }
    else {
	/*erts_fprintf(stderr, "Found module %T\r\n", mod_atom);*/

	int maybe_dirty_nifs = ((entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
				&& (entry->options & ERL_NIF_DIRTY_NIF_OPTION));
	int incr = 0;
	ErlNifFunc* f = entry->funcs;
	for (i=0; i < entry->num_of_funcs && ret==am_ok; i++) {
	    BeamInstr** code_pp;
	    if (!erts_atom_get(f->name, sys_strlen(f->name), &f_atom, ERTS_ATOM_ENC_LATIN1)
		|| (code_pp = get_func_pp(mod->curr.code, f_atom, f->arity))==NULL) {
		ret = load_nif_error(BIF_P,bad_lib,"Function not found %T:%s/%u",
				     mod_atom, f->name, f->arity);
	    }
	    else if (maybe_dirty_nifs && f->flags) {
		/*
		 * If the flags field is non-zero and this emulator was
		 * built with dirty scheduler support, check that the flags
		 * value is legal. But if this emulator was built without
		 * dirty scheduler support, treat a non-zero flags field as
		 * a load error.
		 */
#ifdef ERTS_DIRTY_SCHEDULERS
		if (f->flags != ERL_NIF_DIRTY_JOB_IO_BOUND && f->flags != ERL_NIF_DIRTY_JOB_CPU_BOUND)
		    ret = load_nif_error(BIF_P, bad_lib, "Illegal flags field value %d for NIF %T:%s/%u",
					 f->flags, mod_atom, f->name, f->arity);
#else
		ret = load_nif_error(BIF_P, bad_lib, "NIF %T:%s/%u requires a runtime with dirty scheduler support.",
				     mod_atom, f->name, f->arity);
#endif
	    }
#ifdef ERTS_DIRTY_SCHEDULERS
	    else if (code_pp[1] - code_pp[0] < (5+4))
#else
	    else if (code_pp[1] - code_pp[0] < (5+3))
#endif
	    {
		ret = load_nif_error(BIF_P,bad_lib,"No explicit call to load_nif"
				     " in module (%T:%s/%u too small)",
				     mod_atom, f->name, f->arity);
	    }
	    /*erts_fprintf(stderr, "Found NIF %T:%s/%u\r\n",
	      mod_atom, f->name, f->arity);*/
	    f = next_func(entry, &incr, f);
	}
    }

    if (ret != am_ok) {
	goto error;
    }

    /* Call load, reload or upgrade:
     */


    lib = erts_alloc(ERTS_ALC_T_NIF, sizeof(struct erl_module_nif));
    lib->handle = handle;
    lib->entry = entry;
    erts_refc_init(&lib->rt_cnt, 0);
    erts_refc_init(&lib->rt_dtor_cnt, 0);
    ASSERT(opened_rt_list == NULL);
    lib->mod = mod;
    env.mod_nif = lib;
    if (mod->curr.nif != NULL) { /*************** Reload ******************/
	/*
	 * Repeated load_nif calls from same Erlang module instance ("reload")
	 * is deprecated and was only ment as a development feature not to
	 * be used in production systems. (See warning below)
	 */
	int k, old_incr = 0;
	ErlNifFunc* old_func;
        lib->priv_data = mod->curr.nif->priv_data;

	ASSERT(mod->curr.nif->entry != NULL);
	if (entry->reload == NULL) {
	    ret = load_nif_error(BIF_P,reload,"Reload not supported by this NIF library.");
	    goto error;
	}
	/* Check that no NIF is removed */
	old_func = mod->curr.nif->entry->funcs;
	for (k=0; k < mod->curr.nif->entry->num_of_funcs; k++) {
	    int incr = 0;
	    ErlNifFunc* f = entry->funcs;
	    for (i=0; i < entry->num_of_funcs; i++) {
		if (old_func->arity == f->arity
		    && sys_strcmp(old_func->name, f->name) == 0) {
		    break;
		}
		f = next_func(entry, &incr, f);
	    }
	    if (i == entry->num_of_funcs) {
		ret = load_nif_error(BIF_P,reload,"Reloaded library missing "
				     "function %T:%s/%u\r\n", mod_atom,
				     old_func->name, old_func->arity);
		goto error;
	    }
	    old_func = next_func(mod->curr.nif->entry, &old_incr, old_func);
	}
	erts_pre_nif(&env, BIF_P, lib);
	veto = entry->reload(&env, &lib->priv_data, BIF_ARG_2);
	erts_post_nif(&env);
	if (veto) {
	    ret = load_nif_error(BIF_P, reload, "Library reload-call unsuccessful.");
	}
	else {
	    commit_opened_resource_types(lib);
	    mod->curr.nif->entry = NULL; /* to prevent 'unload' callback */
	    erts_unload_nif(mod->curr.nif);
	    reload_warning = 1;
	}
    }
    else {
	lib->priv_data = NULL;
	if (mod->old.nif != NULL) { /**************** Upgrade ***************/
	    void* prev_old_data = mod->old.nif->priv_data;
	    if (entry->upgrade == NULL) {
		ret = load_nif_error(BIF_P, upgrade, "Upgrade not supported by this NIF library.");
		goto error;
	    }
	    erts_pre_nif(&env, BIF_P, lib);
	    veto = entry->upgrade(&env, &lib->priv_data, &mod->old.nif->priv_data, BIF_ARG_2);
	    erts_post_nif(&env);
	    if (veto) {
		mod->old.nif->priv_data = prev_old_data;
		ret = load_nif_error(BIF_P, upgrade, "Library upgrade-call unsuccessful.");
	    }
	    else
		commit_opened_resource_types(lib);
	}
	else if (entry->load != NULL) { /********* Initial load ***********/
	    erts_pre_nif(&env, BIF_P, lib);
	    veto = entry->load(&env, &lib->priv_data, BIF_ARG_2);
	    erts_post_nif(&env);
	    if (veto) {
		ret = load_nif_error(BIF_P, "load", "Library load-call unsuccessful.");
	    }
	    else
		commit_opened_resource_types(lib);
	}
    }
    if (ret == am_ok) {
	/*
	** Everything ok, patch the beam code with op_call_nif
	*/

	int incr = 0;
	ErlNifFunc* f = entry->funcs;

	mod->curr.nif = lib;
	for (i=0; i < entry->num_of_funcs; i++)
	{
	    BeamInstr* code_ptr;
	    erts_atom_get(f->name, sys_strlen(f->name), &f_atom, ERTS_ATOM_ENC_LATIN1);
	    code_ptr = *get_func_pp(mod->curr.code, f_atom, f->arity);

	    if (code_ptr[1] == 0) {
		code_ptr[5+0] = (BeamInstr) BeamOp(op_call_nif);
	    }
	    else { /* Function traced, patch the original instruction word */
		GenericBp* g = (GenericBp *) code_ptr[1];
		ASSERT(code_ptr[5+0] ==
		       (BeamInstr) BeamOp(op_i_generic_breakpoint));
		g->orig_instr = (BeamInstr) BeamOp(op_call_nif);
	    }
	    if ((entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
		&& (entry->options & ERL_NIF_DIRTY_NIF_OPTION) && f->flags) {
#ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
		code_ptr[5+3] = (BeamInstr) f->fptr;
		code_ptr[5+1] = (f->flags == ERL_NIF_DIRTY_JOB_IO_BOUND) ?
		    (BeamInstr) schedule_dirty_io_nif :
		    (BeamInstr) schedule_dirty_cpu_nif;
#endif
	    }
	    else
		code_ptr[5+1] = (BeamInstr) f->fptr;
	    code_ptr[5+2] = (BeamInstr) lib;
	    f = next_func(entry, &incr, f);
	}
    }
    else {
    error:
	rollback_opened_resource_types();
	ASSERT(ret != am_ok);
        if (lib != NULL) {
	    erts_free(ERTS_ALC_T_NIF, lib);
	}
	if (handle != NULL && !erts_is_static_nif(handle)) {
	    erts_sys_ddll_close(handle);
	}
	erts_sys_ddll_free_error(&errdesc);
    }

    erts_smp_thr_progress_unblock();
    erts_smp_proc_lock(BIF_P, ERTS_PROC_LOCK_MAIN);
    erts_release_code_write_permission();
    erts_free(ERTS_ALC_T_TMP, lib_name);

    if (reload_warning) {
	erts_dsprintf_buf_t* dsbufp = erts_create_logger_dsbuf();
	erts_dsprintf(dsbufp,
		      "Repeated calls to erlang:load_nif from module '%T'.\n\n"
		      "The NIF reload mechanism is deprecated and must not "
		      "be used in production systems.\n", mod_atom);
	erts_send_warning_to_logger(BIF_P->group_leader, dsbufp);
    }
    BIF_RET(ret);
}


void
erts_unload_nif(struct erl_module_nif* lib)
{
    ErlNifResourceType* rt;
    ErlNifResourceType* next;
    ASSERT(erts_smp_thr_progress_is_blocking());
    ASSERT(lib != NULL);
    ASSERT(lib->mod != NULL);
    for (rt = resource_type_list.next;
	 rt != &resource_type_list;
	 rt = next) {

	next = rt->next;
	if (rt->owner == lib) {
	    rt->next->prev = rt->prev;
	    rt->prev->next = rt->next;
	    rt->next = NULL;
	    rt->prev = NULL;
	    if (erts_refc_dectest(&rt->refc, 0) == 0) {
		if (rt->dtor != NULL) {
		    erts_refc_dec(&lib->rt_dtor_cnt, 0);
		}
		erts_refc_dec(&lib->rt_cnt, 0);
		erts_free(ERTS_ALC_T_NIF, rt);
	    }
	}
    }
    if (erts_refc_read(&lib->rt_dtor_cnt, 0) == 0) {
	close_lib(lib);
	if (erts_refc_read(&lib->rt_cnt, 0) == 0) {
	    erts_free(ERTS_ALC_T_NIF, lib);
	    return;
	}
    }
    else {
	ASSERT(erts_refc_read(&lib->rt_cnt, 1) > 0);
    }
    lib->mod = NULL;   /* orphan lib */
}	

void erl_nif_init()
{
    ERTS_CT_ASSERT((offsetof(ErlNifResource,data) % 8) == ERTS_MAGIC_BIN_BYTES_TO_ALIGN);

    resource_type_list.next = &resource_type_list;
    resource_type_list.prev = &resource_type_list;
    resource_type_list.dtor = NULL;
    resource_type_list.owner = NULL;
    resource_type_list.module = THE_NON_VALUE;
    resource_type_list.name = THE_NON_VALUE;
}

#ifdef USE_VM_PROBES
void dtrace_nifenv_str(ErlNifEnv *env, char *process_buf)
{
    dtrace_pid_str(env->proc->common.id, process_buf);
}
#endif

#ifdef READONLY_CHECK
/* Use checksums to assert that NIFs do not write into inspected binaries
*/
static void readonly_check_dtor(struct enif_tmp_obj_t*);
static unsigned calc_checksum(unsigned char* ptr, unsigned size);

struct readonly_check_t
{
    struct enif_tmp_obj_t hdr;
    unsigned char* ptr;
    unsigned size;
    unsigned checksum;
};
static void add_readonly_check(ErlNifEnv* env, unsigned char* ptr, unsigned sz)
{
    ErtsAlcType_t allocator = is_proc_bound(env) ? ERTS_ALC_T_TMP : ERTS_ALC_T_NIF;
    struct readonly_check_t* obj = erts_alloc(allocator, 
					      sizeof(struct readonly_check_t));
    obj->hdr.allocator = allocator;
    obj->hdr.next = env->tmp_obj_list;
    env->tmp_obj_list = &obj->hdr;
    obj->hdr.dtor = &readonly_check_dtor;
    obj->ptr = ptr;
    obj->size = sz;
    obj->checksum = calc_checksum(ptr, sz);    
}
static void readonly_check_dtor(struct enif_tmp_obj_t* o)
{
    struct readonly_check_t* obj = (struct readonly_check_t*) o;
    unsigned chksum = calc_checksum(obj->ptr, obj->size);
    if (chksum != obj->checksum) { 
	fprintf(stderr, "\r\nReadonly data written by NIF, checksums differ"
		" %x != %x\r\nABORTING\r\n", chksum, obj->checksum);
	abort();
    }
    erts_free(obj->hdr.allocator,  obj);
}
static unsigned calc_checksum(unsigned char* ptr, unsigned size)
{
    unsigned i, sum = 0;
    for (i=0; i<size; i++) {
	sum ^= ptr[i] << ((i % 4)*8);
    }
    return sum;
}

#endif /* READONLY_CHECK */

#ifdef HAVE_USE_DTRACE

#define MESSAGE_BUFSIZ 1024

static void get_string_maybe(ErlNifEnv *env, const ERL_NIF_TERM term,
		      char **ptr, char *buf, int bufsiz)
{
    ErlNifBinary str_bin;

    if (!enif_inspect_iolist_as_binary(env, term, &str_bin) ||
        str_bin.size > bufsiz) {
        *ptr = NULL;
    } else {
        memcpy(buf, (char *) str_bin.data, str_bin.size);
        buf[str_bin.size] = '\0';
        *ptr = buf;
    }
}

ERL_NIF_TERM erl_nif_user_trace_s1(ErlNifEnv* env, int argc,
                                   const ERL_NIF_TERM argv[])
{
    ErlNifBinary message_bin;
    DTRACE_CHARBUF(messagebuf, MESSAGE_BUFSIZ + 1);

    if (DTRACE_ENABLED(user_trace_s1)) {
	if (!enif_inspect_iolist_as_binary(env, argv[0], &message_bin) ||
	    message_bin.size > MESSAGE_BUFSIZ) {
	    return am_badarg;
	}
	memcpy(messagebuf, (char *) message_bin.data, message_bin.size);
        messagebuf[message_bin.size] = '\0';
	DTRACE1(user_trace_s1, messagebuf);
	return am_true;
    } else {
	return am_false;
    }
}

ERL_NIF_TERM erl_nif_user_trace_i4s4(ErlNifEnv* env, int argc,
                                     const ERL_NIF_TERM argv[])
{
    DTRACE_CHARBUF(procbuf, 32 + 1);
    DTRACE_CHARBUF(user_tagbuf, MESSAGE_BUFSIZ + 1);
    char *utbuf = NULL;
    ErlNifSInt64 i1, i2, i3, i4;
    DTRACE_CHARBUF(messagebuf1, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf2, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf3, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf4, MESSAGE_BUFSIZ + 1);
    char *mbuf1 = NULL, *mbuf2 = NULL, *mbuf3 = NULL, *mbuf4 = NULL;
    
    if (DTRACE_ENABLED(user_trace_i4s4)) {
	dtrace_nifenv_str(env, procbuf);
        get_string_maybe(env, argv[0], &utbuf, user_tagbuf, MESSAGE_BUFSIZ);
        if (! enif_get_int64(env, argv[1], &i1))
            i1 = 0;
        if (! enif_get_int64(env, argv[2], &i2))
            i2 = 0;
        if (! enif_get_int64(env, argv[3], &i3))
            i3 = 0;
        if (! enif_get_int64(env, argv[4], &i4))
            i4 = 0;
        get_string_maybe(env, argv[5], &mbuf1, messagebuf1, MESSAGE_BUFSIZ);
        get_string_maybe(env, argv[6], &mbuf2, messagebuf2, MESSAGE_BUFSIZ);
        get_string_maybe(env, argv[7], &mbuf3, messagebuf3, MESSAGE_BUFSIZ);
        get_string_maybe(env, argv[8], &mbuf4, messagebuf4, MESSAGE_BUFSIZ);
	DTRACE10(user_trace_i4s4, procbuf, utbuf,
		 i1, i2, i3, i4, mbuf1, mbuf2, mbuf3, mbuf4);
	return am_true;
    } else {
	return am_false;
    }
}

#define DTRACE10_LABEL(name, label, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) \
    erlang_##name##label((a0), (a1), (a2), (a3), (a4), (a5), (a6), (a7), (a8), (a9))
#define N_STATEMENT(the_label) \
   case the_label: \
      if (DTRACE_ENABLED(user_trace_n##the_label)) { \
          dtrace_nifenv_str(env, procbuf); \
          get_string_maybe(env, argv[1], &utbuf, user_tagbuf, MESSAGE_BUFSIZ); \
          if (! enif_get_int64(env, argv[2], &i1)) \
              i1 = 0; \
          if (! enif_get_int64(env, argv[3], &i2)) \
              i2 = 0; \
          if (! enif_get_int64(env, argv[4], &i3)) \
              i3 = 0; \
          if (! enif_get_int64(env, argv[5], &i4)) \
              i4 = 0; \
          get_string_maybe(env, argv[6], &mbuf1, messagebuf1, MESSAGE_BUFSIZ); \
          get_string_maybe(env, argv[7], &mbuf2, messagebuf2, MESSAGE_BUFSIZ); \
          get_string_maybe(env, argv[8], &mbuf3, messagebuf3, MESSAGE_BUFSIZ); \
          get_string_maybe(env, argv[9], &mbuf4, messagebuf4, MESSAGE_BUFSIZ); \
          DTRACE10_LABEL(user_trace_n, the_label, procbuf, utbuf,    \
                         i1, i2, i3, i4, mbuf1, mbuf2, mbuf3, mbuf4); \
          return am_true; \
      } else { \
          return am_false; \
      } \
      break

ERL_NIF_TERM erl_nif_user_trace_n(ErlNifEnv* env, int argc,
				  const ERL_NIF_TERM argv[])
{
    DTRACE_CHARBUF(procbuf, 32 + 1);
    DTRACE_CHARBUF(user_tagbuf, MESSAGE_BUFSIZ + 1);
    char *utbuf = NULL;
    ErlNifSInt64 i1, i2, i3, i4;
    DTRACE_CHARBUF(messagebuf1, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf2, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf3, MESSAGE_BUFSIZ + 1);
    DTRACE_CHARBUF(messagebuf4, MESSAGE_BUFSIZ + 1);
    char *mbuf1 = NULL, *mbuf2 = NULL, *mbuf3 = NULL, *mbuf4 = NULL;
    ErlNifSInt64 label = 0;

    if (! enif_get_int64(env, argv[0], &label) || label < 0 || label > 1023) {
	return am_badarg;
    }
    switch (label) {
        N_STATEMENT(0);
        N_STATEMENT(1);
        N_STATEMENT(2);
        N_STATEMENT(3);
        N_STATEMENT(4);
        N_STATEMENT(5);
        N_STATEMENT(6);
        N_STATEMENT(7);
        N_STATEMENT(8);
        N_STATEMENT(9);
        N_STATEMENT(10);
        N_STATEMENT(11);
        N_STATEMENT(12);
        N_STATEMENT(13);
        N_STATEMENT(14);
        N_STATEMENT(15);
        N_STATEMENT(16);
        N_STATEMENT(17);
        N_STATEMENT(18);
        N_STATEMENT(19);
        N_STATEMENT(20);
        N_STATEMENT(21);
        N_STATEMENT(22);
        N_STATEMENT(23);
        N_STATEMENT(24);
        N_STATEMENT(25);
        N_STATEMENT(26);
        N_STATEMENT(27);
        N_STATEMENT(28);
        N_STATEMENT(29);
        N_STATEMENT(30);
        N_STATEMENT(31);
        N_STATEMENT(32);
        N_STATEMENT(33);
        N_STATEMENT(34);
        N_STATEMENT(35);
        N_STATEMENT(36);
        N_STATEMENT(37);
        N_STATEMENT(38);
        N_STATEMENT(39);
        N_STATEMENT(40);
        N_STATEMENT(41);
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        N_STATEMENT(44);
        N_STATEMENT(45);
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        N_STATEMENT(48);
        N_STATEMENT(49);
        N_STATEMENT(50);
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        N_STATEMENT(55);
        N_STATEMENT(56);
        N_STATEMENT(57);
        N_STATEMENT(58);
        N_STATEMENT(59);
        N_STATEMENT(60);
        N_STATEMENT(61);
        N_STATEMENT(62);
        N_STATEMENT(63);
        N_STATEMENT(64);
        N_STATEMENT(65);
        N_STATEMENT(66);
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        N_STATEMENT(69);
        N_STATEMENT(70);
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        N_STATEMENT(78);
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        N_STATEMENT(80);
        N_STATEMENT(81);
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        N_STATEMENT(84);
        N_STATEMENT(85);
        N_STATEMENT(86);
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        N_STATEMENT(88);
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        N_STATEMENT(90);
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        N_STATEMENT(93);
        N_STATEMENT(94);
        N_STATEMENT(95);
        N_STATEMENT(96);
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        N_STATEMENT(98);
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        N_STATEMENT(101);
        N_STATEMENT(102);
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        N_STATEMENT(105);
        N_STATEMENT(106);
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        N_STATEMENT(109);
        N_STATEMENT(110);
        N_STATEMENT(111);
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        N_STATEMENT(113);
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        N_STATEMENT(115);
        N_STATEMENT(116);
        N_STATEMENT(117);
        N_STATEMENT(118);
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        N_STATEMENT(120);
        N_STATEMENT(121);
        N_STATEMENT(122);
        N_STATEMENT(123);
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        N_STATEMENT(125);
        N_STATEMENT(126);
        N_STATEMENT(127);
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        N_STATEMENT(133);
        N_STATEMENT(134);
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        N_STATEMENT(136);
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        N_STATEMENT(138);
        N_STATEMENT(139);
        N_STATEMENT(140);
        N_STATEMENT(141);
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        N_STATEMENT(145);
        N_STATEMENT(146);
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        N_STATEMENT(178);
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        N_STATEMENT(186);
        N_STATEMENT(187);
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        N_STATEMENT(191);
        N_STATEMENT(192);
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        N_STATEMENT(195);
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        N_STATEMENT(198);
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        N_STATEMENT(200);
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        N_STATEMENT(202);
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        N_STATEMENT(205);
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        N_STATEMENT(210);
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        N_STATEMENT(215);
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        N_STATEMENT(455);
        N_STATEMENT(456);
        N_STATEMENT(457);
        N_STATEMENT(458);
        N_STATEMENT(459);
        N_STATEMENT(460);
        N_STATEMENT(461);
        N_STATEMENT(462);
        N_STATEMENT(463);
        N_STATEMENT(464);
        N_STATEMENT(465);
        N_STATEMENT(466);
        N_STATEMENT(467);
        N_STATEMENT(468);
        N_STATEMENT(469);
        N_STATEMENT(470);
        N_STATEMENT(471);
        N_STATEMENT(472);
        N_STATEMENT(473);
        N_STATEMENT(474);
        N_STATEMENT(475);
        N_STATEMENT(476);
        N_STATEMENT(477);
        N_STATEMENT(478);
        N_STATEMENT(479);
        N_STATEMENT(480);
        N_STATEMENT(481);
        N_STATEMENT(482);
        N_STATEMENT(483);
        N_STATEMENT(484);
        N_STATEMENT(485);
        N_STATEMENT(486);
        N_STATEMENT(487);
        N_STATEMENT(488);
        N_STATEMENT(489);
        N_STATEMENT(490);
        N_STATEMENT(491);
        N_STATEMENT(492);
        N_STATEMENT(493);
        N_STATEMENT(494);
        N_STATEMENT(495);
        N_STATEMENT(496);
        N_STATEMENT(497);
        N_STATEMENT(498);
        N_STATEMENT(499);
        N_STATEMENT(500);
        N_STATEMENT(501);
        N_STATEMENT(502);
        N_STATEMENT(503);
        N_STATEMENT(504);
        N_STATEMENT(505);
        N_STATEMENT(506);
        N_STATEMENT(507);
        N_STATEMENT(508);
        N_STATEMENT(509);
        N_STATEMENT(510);
        N_STATEMENT(511);
        N_STATEMENT(512);
        N_STATEMENT(513);
        N_STATEMENT(514);
        N_STATEMENT(515);
        N_STATEMENT(516);
        N_STATEMENT(517);
        N_STATEMENT(518);
        N_STATEMENT(519);
        N_STATEMENT(520);
        N_STATEMENT(521);
        N_STATEMENT(522);
        N_STATEMENT(523);
        N_STATEMENT(524);
        N_STATEMENT(525);
        N_STATEMENT(526);
        N_STATEMENT(527);
        N_STATEMENT(528);
        N_STATEMENT(529);
        N_STATEMENT(530);
        N_STATEMENT(531);
        N_STATEMENT(532);
        N_STATEMENT(533);
        N_STATEMENT(534);
        N_STATEMENT(535);
        N_STATEMENT(536);
        N_STATEMENT(537);
        N_STATEMENT(538);
        N_STATEMENT(539);
        N_STATEMENT(540);
        N_STATEMENT(541);
        N_STATEMENT(542);
        N_STATEMENT(543);
        N_STATEMENT(544);
        N_STATEMENT(545);
        N_STATEMENT(546);
        N_STATEMENT(547);
        N_STATEMENT(548);
        N_STATEMENT(549);
        N_STATEMENT(550);
        N_STATEMENT(551);
        N_STATEMENT(552);
        N_STATEMENT(553);
        N_STATEMENT(554);
        N_STATEMENT(555);
        N_STATEMENT(556);
        N_STATEMENT(557);
        N_STATEMENT(558);
        N_STATEMENT(559);
        N_STATEMENT(560);
        N_STATEMENT(561);
        N_STATEMENT(562);
        N_STATEMENT(563);
        N_STATEMENT(564);
        N_STATEMENT(565);
        N_STATEMENT(566);
        N_STATEMENT(567);
        N_STATEMENT(568);
        N_STATEMENT(569);
        N_STATEMENT(570);
        N_STATEMENT(571);
        N_STATEMENT(572);
        N_STATEMENT(573);
        N_STATEMENT(574);
        N_STATEMENT(575);
        N_STATEMENT(576);
        N_STATEMENT(577);
        N_STATEMENT(578);
        N_STATEMENT(579);
        N_STATEMENT(580);
        N_STATEMENT(581);
        N_STATEMENT(582);
        N_STATEMENT(583);
        N_STATEMENT(584);
        N_STATEMENT(585);
        N_STATEMENT(586);
        N_STATEMENT(587);
        N_STATEMENT(588);
        N_STATEMENT(589);
        N_STATEMENT(590);
        N_STATEMENT(591);
        N_STATEMENT(592);
        N_STATEMENT(593);
        N_STATEMENT(594);
        N_STATEMENT(595);
        N_STATEMENT(596);
        N_STATEMENT(597);
        N_STATEMENT(598);
        N_STATEMENT(599);
        N_STATEMENT(600);
        N_STATEMENT(601);
        N_STATEMENT(602);
        N_STATEMENT(603);
        N_STATEMENT(604);
        N_STATEMENT(605);
        N_STATEMENT(606);
        N_STATEMENT(607);
        N_STATEMENT(608);
        N_STATEMENT(609);
        N_STATEMENT(610);
        N_STATEMENT(611);
        N_STATEMENT(612);
        N_STATEMENT(613);
        N_STATEMENT(614);
        N_STATEMENT(615);
        N_STATEMENT(616);
        N_STATEMENT(617);
        N_STATEMENT(618);
        N_STATEMENT(619);
        N_STATEMENT(620);
        N_STATEMENT(621);
        N_STATEMENT(622);
        N_STATEMENT(623);
        N_STATEMENT(624);
        N_STATEMENT(625);
        N_STATEMENT(626);
        N_STATEMENT(627);
        N_STATEMENT(628);
        N_STATEMENT(629);
        N_STATEMENT(630);
        N_STATEMENT(631);
        N_STATEMENT(632);
        N_STATEMENT(633);
        N_STATEMENT(634);
        N_STATEMENT(635);
        N_STATEMENT(636);
        N_STATEMENT(637);
        N_STATEMENT(638);
        N_STATEMENT(639);
        N_STATEMENT(640);
        N_STATEMENT(641);
        N_STATEMENT(642);
        N_STATEMENT(643);
        N_STATEMENT(644);
        N_STATEMENT(645);
        N_STATEMENT(646);
        N_STATEMENT(647);
        N_STATEMENT(648);
        N_STATEMENT(649);
        N_STATEMENT(650);
        N_STATEMENT(651);
        N_STATEMENT(652);
        N_STATEMENT(653);
        N_STATEMENT(654);
        N_STATEMENT(655);
        N_STATEMENT(656);
        N_STATEMENT(657);
        N_STATEMENT(658);
        N_STATEMENT(659);
        N_STATEMENT(660);
        N_STATEMENT(661);
        N_STATEMENT(662);
        N_STATEMENT(663);
        N_STATEMENT(664);
        N_STATEMENT(665);
        N_STATEMENT(666);
        N_STATEMENT(667);
        N_STATEMENT(668);
        N_STATEMENT(669);
        N_STATEMENT(670);
        N_STATEMENT(671);
        N_STATEMENT(672);
        N_STATEMENT(673);
        N_STATEMENT(674);
        N_STATEMENT(675);
        N_STATEMENT(676);
        N_STATEMENT(677);
        N_STATEMENT(678);
        N_STATEMENT(679);
        N_STATEMENT(680);
        N_STATEMENT(681);
        N_STATEMENT(682);
        N_STATEMENT(683);
        N_STATEMENT(684);
        N_STATEMENT(685);
        N_STATEMENT(686);
        N_STATEMENT(687);
        N_STATEMENT(688);
        N_STATEMENT(689);
        N_STATEMENT(690);
        N_STATEMENT(691);
        N_STATEMENT(692);
        N_STATEMENT(693);
        N_STATEMENT(694);
        N_STATEMENT(695);
        N_STATEMENT(696);
        N_STATEMENT(697);
        N_STATEMENT(698);
        N_STATEMENT(699);
        N_STATEMENT(700);
        N_STATEMENT(701);
        N_STATEMENT(702);
        N_STATEMENT(703);
        N_STATEMENT(704);
        N_STATEMENT(705);
        N_STATEMENT(706);
        N_STATEMENT(707);
        N_STATEMENT(708);
        N_STATEMENT(709);
        N_STATEMENT(710);
        N_STATEMENT(711);
        N_STATEMENT(712);
        N_STATEMENT(713);
        N_STATEMENT(714);
        N_STATEMENT(715);
        N_STATEMENT(716);
        N_STATEMENT(717);
        N_STATEMENT(718);
        N_STATEMENT(719);
        N_STATEMENT(720);
        N_STATEMENT(721);
        N_STATEMENT(722);
        N_STATEMENT(723);
        N_STATEMENT(724);
        N_STATEMENT(725);
        N_STATEMENT(726);
        N_STATEMENT(727);
        N_STATEMENT(728);
        N_STATEMENT(729);
        N_STATEMENT(730);
        N_STATEMENT(731);
        N_STATEMENT(732);
        N_STATEMENT(733);
        N_STATEMENT(734);
        N_STATEMENT(735);
        N_STATEMENT(736);
        N_STATEMENT(737);
        N_STATEMENT(738);
        N_STATEMENT(739);
        N_STATEMENT(740);
        N_STATEMENT(741);
        N_STATEMENT(742);
        N_STATEMENT(743);
        N_STATEMENT(744);
        N_STATEMENT(745);
        N_STATEMENT(746);
        N_STATEMENT(747);
        N_STATEMENT(748);
        N_STATEMENT(749);
        N_STATEMENT(750);
        N_STATEMENT(751);
        N_STATEMENT(752);
        N_STATEMENT(753);
        N_STATEMENT(754);
        N_STATEMENT(755);
        N_STATEMENT(756);
        N_STATEMENT(757);
        N_STATEMENT(758);
        N_STATEMENT(759);
        N_STATEMENT(760);
        N_STATEMENT(761);
        N_STATEMENT(762);
        N_STATEMENT(763);
        N_STATEMENT(764);
        N_STATEMENT(765);
        N_STATEMENT(766);
        N_STATEMENT(767);
        N_STATEMENT(768);
        N_STATEMENT(769);
        N_STATEMENT(770);
        N_STATEMENT(771);
        N_STATEMENT(772);
        N_STATEMENT(773);
        N_STATEMENT(774);
        N_STATEMENT(775);
        N_STATEMENT(776);
        N_STATEMENT(777);
        N_STATEMENT(778);
        N_STATEMENT(779);
        N_STATEMENT(780);
        N_STATEMENT(781);
        N_STATEMENT(782);
        N_STATEMENT(783);
        N_STATEMENT(784);
        N_STATEMENT(785);
        N_STATEMENT(786);
        N_STATEMENT(787);
        N_STATEMENT(788);
        N_STATEMENT(789);
        N_STATEMENT(790);
        N_STATEMENT(791);
        N_STATEMENT(792);
        N_STATEMENT(793);
        N_STATEMENT(794);
        N_STATEMENT(795);
        N_STATEMENT(796);
        N_STATEMENT(797);
        N_STATEMENT(798);
        N_STATEMENT(799);
        N_STATEMENT(800);
        N_STATEMENT(801);
        N_STATEMENT(802);
        N_STATEMENT(803);
        N_STATEMENT(804);
        N_STATEMENT(805);
        N_STATEMENT(806);
        N_STATEMENT(807);
        N_STATEMENT(808);
        N_STATEMENT(809);
        N_STATEMENT(810);
        N_STATEMENT(811);
        N_STATEMENT(812);
        N_STATEMENT(813);
        N_STATEMENT(814);
        N_STATEMENT(815);
        N_STATEMENT(816);
        N_STATEMENT(817);
        N_STATEMENT(818);
        N_STATEMENT(819);
        N_STATEMENT(820);
        N_STATEMENT(821);
        N_STATEMENT(822);
        N_STATEMENT(823);
        N_STATEMENT(824);
        N_STATEMENT(825);
        N_STATEMENT(826);
        N_STATEMENT(827);
        N_STATEMENT(828);
        N_STATEMENT(829);
        N_STATEMENT(830);
        N_STATEMENT(831);
        N_STATEMENT(832);
        N_STATEMENT(833);
        N_STATEMENT(834);
        N_STATEMENT(835);
        N_STATEMENT(836);
        N_STATEMENT(837);
        N_STATEMENT(838);
        N_STATEMENT(839);
        N_STATEMENT(840);
        N_STATEMENT(841);
        N_STATEMENT(842);
        N_STATEMENT(843);
        N_STATEMENT(844);
        N_STATEMENT(845);
        N_STATEMENT(846);
        N_STATEMENT(847);
        N_STATEMENT(848);
        N_STATEMENT(849);
        N_STATEMENT(850);
        N_STATEMENT(851);
        N_STATEMENT(852);
        N_STATEMENT(853);
        N_STATEMENT(854);
        N_STATEMENT(855);
        N_STATEMENT(856);
        N_STATEMENT(857);
        N_STATEMENT(858);
        N_STATEMENT(859);
        N_STATEMENT(860);
        N_STATEMENT(861);
        N_STATEMENT(862);
        N_STATEMENT(863);
        N_STATEMENT(864);
        N_STATEMENT(865);
        N_STATEMENT(866);
        N_STATEMENT(867);
        N_STATEMENT(868);
        N_STATEMENT(869);
        N_STATEMENT(870);
        N_STATEMENT(871);
        N_STATEMENT(872);
        N_STATEMENT(873);
        N_STATEMENT(874);
        N_STATEMENT(875);
        N_STATEMENT(876);
        N_STATEMENT(877);
        N_STATEMENT(878);
        N_STATEMENT(879);
        N_STATEMENT(880);
        N_STATEMENT(881);
        N_STATEMENT(882);
        N_STATEMENT(883);
        N_STATEMENT(884);
        N_STATEMENT(885);
        N_STATEMENT(886);
        N_STATEMENT(887);
        N_STATEMENT(888);
        N_STATEMENT(889);
        N_STATEMENT(890);
        N_STATEMENT(891);
        N_STATEMENT(892);
        N_STATEMENT(893);
        N_STATEMENT(894);
        N_STATEMENT(895);
        N_STATEMENT(896);
        N_STATEMENT(897);
        N_STATEMENT(898);
        N_STATEMENT(899);
        N_STATEMENT(900);
        N_STATEMENT(901);
        N_STATEMENT(902);
        N_STATEMENT(903);
        N_STATEMENT(904);
        N_STATEMENT(905);
        N_STATEMENT(906);
        N_STATEMENT(907);
        N_STATEMENT(908);
        N_STATEMENT(909);
        N_STATEMENT(910);
        N_STATEMENT(911);
        N_STATEMENT(912);
        N_STATEMENT(913);
        N_STATEMENT(914);
        N_STATEMENT(915);
        N_STATEMENT(916);
        N_STATEMENT(917);
        N_STATEMENT(918);
        N_STATEMENT(919);
        N_STATEMENT(920);
        N_STATEMENT(921);
        N_STATEMENT(922);
        N_STATEMENT(923);
        N_STATEMENT(924);
        N_STATEMENT(925);
        N_STATEMENT(926);
        N_STATEMENT(927);
        N_STATEMENT(928);
        N_STATEMENT(929);
        N_STATEMENT(930);
        N_STATEMENT(931);
        N_STATEMENT(932);
        N_STATEMENT(933);
        N_STATEMENT(934);
        N_STATEMENT(935);
        N_STATEMENT(936);
        N_STATEMENT(937);
        N_STATEMENT(938);
        N_STATEMENT(939);
        N_STATEMENT(940);
        N_STATEMENT(941);
        N_STATEMENT(942);
        N_STATEMENT(943);
        N_STATEMENT(944);
        N_STATEMENT(945);
        N_STATEMENT(946);
        N_STATEMENT(947);
        N_STATEMENT(948);
        N_STATEMENT(949);
        N_STATEMENT(950);
    }
    return am_error;          /* NOTREACHED, shut up the compiler */
}

#endif /* HAVE_USE_DTRACE */