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

/*
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2014. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 *
 * Author: Björn-Egil Dahlberg
 */

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

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

#include "erl_map.h"
#include "erl_hashmap.h"

/* BIFs
 *
 * DONE:
 * - erlang:is_map/1
 * - erlang:map_size/1
 *
 * - maps:find/2
 * - maps:from_list/1
 * - maps:get/2
 * - maps:is_key/2
 * - maps:keys/1
 * - maps:merge/2
 * - maps:new/0
 * - maps:put/3
 * - maps:remove/2
 * - maps:to_list/1
 * - maps:update/3
 * - maps:values/1
 *
 * TODO:
 * - maps:foldl/3
 * - maps:foldr/3
 * - maps:map/3
 * - maps:size/1
 * - maps:without/2
 *
 * DEBUG: for sharing calculation
 * - erts_internal:map_to_tuple_keys/1
 */

static const Eterm *hashmap_get(Uint32 hx, Eterm key, Eterm node);
static Eterm hashmap_insert(Process *p, Uint32 hx, Eterm key, Eterm value, Eterm node, int is_update);
static Eterm hashmap_to_list(Process *p, Eterm map);
static Eterm hashmap_keys(Process *p, Eterm map);
static Eterm hashmap_values(Process *p, Eterm map);
static Eterm hashmap_delete(Process *p, Uint32 hx, Eterm key, Eterm node);

/* erlang:map_size/1
 * the corresponding instruction is implemented in:
 *     beam/erl_bif_guard.c
 */

BIF_RETTYPE map_size_1(BIF_ALIST_1) {
    if (is_map(BIF_ARG_1)) {
	Eterm *hp;
	Uint hsz  = 0;
	map_t *mp = (map_t*)map_val(BIF_ARG_1);
	Uint n    = map_get_size(mp);

	erts_bld_uint(NULL, &hsz, n);
	hp = HAlloc(BIF_P, hsz);
	BIF_RET(erts_bld_uint(&hp, NULL, n));
    } else if (is_hashmap(BIF_ARG_1)) {
	Eterm *head, *hp, res;
	Uint size, hsz=0;

	head = hashmap_val(BIF_ARG_1);
	size = head[1];
	(void) erts_bld_uint(NULL, &hsz, size);
	hp = HAlloc(BIF_P, hsz);
	res = erts_bld_uint(&hp, NULL, size);
	BIF_RET(res);
    }

    BIF_ERROR(BIF_P, BADARG);
}

/* maps:to_list/1 */

BIF_RETTYPE maps_to_list_1(BIF_ALIST_1) {
    if (is_map(BIF_ARG_1)) {
	Uint n;
	Eterm* hp;
	Eterm *ks,*vs, res, tup;
	map_t *mp = (map_t*)map_val(BIF_ARG_1);

	ks  = map_get_keys(mp);
	vs  = map_get_values(mp);
	n   = map_get_size(mp);
	hp  = HAlloc(BIF_P, (2 + 3) * n);
	res = NIL;

	while(n--) {
	    tup = TUPLE2(hp, ks[n], vs[n]); hp += 3;
	    res = CONS(hp, tup, res); hp += 2;
	}

	BIF_RET(res);
    } else if (is_hashmap(BIF_ARG_1)) {
	return hashmap_to_list(BIF_P, BIF_ARG_1);
    }

    BIF_ERROR(BIF_P, BADARG);
}

/* maps:find/2
 * return value if key *matches* a key in the map
 */

const Eterm *
#if HALFWORD_HEAP
erts_maps_get_rel(Eterm key, Eterm map, Eterm *map_base)
#else
erts_maps_get(Eterm key, Eterm map)
#endif
{
    Uint32 hx;
    if (is_map(map)) {
	Eterm *ks, *vs;
	map_t *mp;
	Uint n, i;

	mp  = (map_t *)map_val_rel(map, map_base);
	n   = map_get_size(mp);

	if (n == 0) {
	    return NULL;
	}

	ks  = (Eterm *)tuple_val_rel(mp->keys, map_base) + 1;
	vs  = map_get_values(mp);

	if (is_immed(key)) {
	    for (i = 0; i < n; i++) {
		if (ks[i] == key) {
		    return &vs[i];
		}
	    }
	}

	for (i = 0; i < n; i++) {
	    if (eq_rel(ks[i], NULL, key, map_base)) {
		return &vs[i];
	    }
	}
	return NULL;
    }
    ASSERT(is_hashmap(map));
    hx = hashmap_make_hash(key);

    return hashmap_get(hx, key, map);
}

BIF_RETTYPE maps_find_2(BIF_ALIST_2) {
    if (is_map(BIF_ARG_2) || is_hashmap(BIF_ARG_2)) {
        Eterm *hp, res;
        const Eterm *value;

        value = erts_maps_get(BIF_ARG_1, BIF_ARG_2);
	if (value) {
	    hp    = HAlloc(BIF_P, 3);
	    res   = make_tuple(hp);
	    *hp++ = make_arityval(2);
	    *hp++ = am_ok;
            *hp++ = *value;
	    BIF_RET(res);
	}
	BIF_RET(am_error);
    }
    BIF_ERROR(BIF_P, BADARG);
}

/* maps:get/2
 * return value if key *matches* a key in the map
 * exception bad_key if none matches
 */

BIF_RETTYPE maps_get_2(BIF_ALIST_2) {
    if (is_map(BIF_ARG_2) || is_hashmap(BIF_ARG_2)) {
	Eterm *hp;
        Eterm error;
        const Eterm *value;
	char *s_error;

        value = erts_maps_get(BIF_ARG_1, BIF_ARG_2);
        if (value) {
            BIF_RET(*value);
	}

	s_error = "bad_key";
	error = am_atom_put(s_error, sys_strlen(s_error));

	hp = HAlloc(BIF_P, 3);
	BIF_P->fvalue = TUPLE2(hp, error, BIF_ARG_1);
	BIF_ERROR(BIF_P, EXC_ERROR_2);
    }
    BIF_ERROR(BIF_P, BADARG);
}

/* maps:from_list/1
 * List may be unsorted [{K,V}]
 */

BIF_RETTYPE maps_from_list_1(BIF_ALIST_1) {
    Eterm *kv, item = BIF_ARG_1;
    Eterm *hp, *thp,*vs, *ks, keys, res;
    map_t *mp;
    Uint  size = 0, unused_size = 0;
    Sint  c = 0;
    Sint  idx = 0;

    if (is_list(item) || is_nil(item)) {

	/* Calculate size and check validity */

	while(is_list(item)) {
	    res = CAR(list_val(item));
	    if (is_not_tuple(res))
		goto error;

	    kv = tuple_val(res);
	    if (*kv != make_arityval(2))
		goto error;

	    size++;
	    item = CDR(list_val(item));
	}

	if (is_not_nil(item))
	    goto error;

	hp    = HAlloc(BIF_P, 3 + 1 + (2 * size));
	thp   = hp;
	keys  = make_tuple(hp);
	*hp++ = make_arityval(size);
	ks    = hp;
	hp   += size;
	mp    = (map_t*)hp;
	res   = make_map(mp);
	hp   += MAP_HEADER_SIZE;
	vs    = hp;

	mp->thing_word = MAP_HEADER;
	mp->size = size; /* set later, might shrink*/
	mp->keys = keys;

	if (size == 0)
	    BIF_RET(res);

	item  = BIF_ARG_1;

	/* first entry */
	kv    = tuple_val(CAR(list_val(item)));
	ks[0] = kv[1];
	vs[0] = kv[2];
	size  = 1;
	item  = CDR(list_val(item));

	/* insert sort key/value pairs */
	while(is_list(item)) {

	    kv = tuple_val(CAR(list_val(item)));

	    /* compare ks backwards
	     * idx represent word index to be written (hole position).
	     * We cannot copy the elements when searching since we might
	     * have an equal key. So we search for just the index first =(
	     *
	     * It is perhaps faster to move the values in the first pass.
	     * Check for uniqueness during insert phase and then have a
	     * second phace compacting the map if duplicates are found
	     * during insert. .. or do someother sort .. shell-sort perhaps.
	     */

	    idx = size;

	    while(idx > 0 && (c = CMP_TERM(kv[1],ks[idx-1])) < 0) { idx--; }

	    if (c == 0) {
		/* last compare was equal,
		 * i.e. we have to release memory
		 * and overwrite that key/value
		 */
		ks[idx-1] = kv[1];
		vs[idx-1] = kv[2];
		unused_size++;
	    } else {
		Uint i = size;
		while(i > idx) {
		    ks[i] = ks[i-1];
		    vs[i] = vs[i-1];
		    i--;
		}
		ks[idx] = kv[1];
		vs[idx] = kv[2];
		size++;
	    }
	    item = CDR(list_val(item));
	}

	if (unused_size) {
	    /* the key tuple is embedded in the heap
	     * write a bignum to clear it.
	     */
	    /* release values as normal since they are on the top of the heap */

	    ks[size] = make_pos_bignum_header(unused_size - 1);
	    HRelease(BIF_P, vs + size + unused_size, vs + size);
	}

	*thp = make_arityval(size);
	mp->size = size;
	BIF_RET(res);
    }

error:

    BIF_ERROR(BIF_P, BADARG);
}

/* maps:is_key/2
 */

BIF_RETTYPE maps_is_key_2(BIF_ALIST_2) {
    if (is_map(BIF_ARG_2) || is_hashmap(BIF_ARG_2)) {
	BIF_RET(erts_maps_get(BIF_ARG_1, BIF_ARG_2) ? am_true : am_false);
    }
    BIF_ERROR(BIF_P, BADARG);
}

/* maps:keys/1
 */

BIF_RETTYPE maps_keys_1(BIF_ALIST_1) {
    if (is_map(BIF_ARG_1)) {
	Eterm *hp, *ks, res = NIL;
	map_t *mp;
	Uint n;

	mp  = (map_t*)map_val(BIF_ARG_1);
	n   = map_get_size(mp);

	if (n == 0)
	    BIF_RET(res);

	hp  = HAlloc(BIF_P, (2 * n));
	ks  = map_get_keys(mp);

	while(n--) {
	    res = CONS(hp, ks[n], res); hp += 2;
	}

	BIF_RET(res);
    } else if (is_hashmap(BIF_ARG_1)) {
	BIF_RET(hashmap_keys(BIF_P, BIF_ARG_1));
    }
    BIF_ERROR(BIF_P, BADARG);
}
/* maps:merge/2
 */

BIF_RETTYPE maps_merge_2(BIF_ALIST_2) {
    if (is_map(BIF_ARG_1) && is_map(BIF_ARG_2)) {
	Eterm *hp,*thp;
	Eterm tup;
	Eterm *ks,*vs,*ks1,*vs1,*ks2,*vs2;
	map_t *mp1,*mp2,*mp_new;
	Uint n1,n2,i1,i2,need,unused_size=0;
	int c = 0;

	mp1  = (map_t*)map_val(BIF_ARG_1);
	mp2  = (map_t*)map_val(BIF_ARG_2);
	n1   = map_get_size(mp1);
	n2   = map_get_size(mp2);

	need = MAP_HEADER_SIZE + 1 + 2*(n1 + n2);

	hp     = HAlloc(BIF_P, need);
	thp    = hp;
	tup    = make_tuple(thp);
	ks     = hp + 1; hp += 1 + n1 + n2;
	mp_new = (map_t*)hp; hp += MAP_HEADER_SIZE;
	vs     = hp; hp += n1 + n2;

	mp_new->thing_word = MAP_HEADER;
	mp_new->size = 0;
	mp_new->keys = tup;

	i1  = 0; i2 = 0;
	ks1 = map_get_keys(mp1);
	vs1 = map_get_values(mp1);
	ks2 = map_get_keys(mp2);
	vs2 = map_get_values(mp2);

	while(i1 < n1 && i2 < n2) {
	    c = CMP_TERM(ks1[i1],ks2[i2]);
	    if ( c == 0) {
		/* use righthand side arguments map value,
		 * but advance both maps */
		*ks++ = ks2[i2];
		*vs++ = vs2[i2];
		i1++, i2++, unused_size++;
	    } else if ( c < 0) {
		*ks++ = ks1[i1];
		*vs++ = vs1[i1];
		i1++;
	    } else {
		*ks++ = ks2[i2];
		*vs++ = vs2[i2];
		i2++;
	    }
	}

	/* copy remaining */
	while (i1 < n1) {
	    *ks++ = ks1[i1];
	    *vs++ = vs1[i1];
	    i1++;
	}

	while (i2 < n2) {
	    *ks++ = ks2[i2];
	    *vs++ = vs2[i2];
	    i2++;
	}

	if (unused_size) {
	    /* the key tuple is embedded in the heap, write a bignum to clear it.
	     *
	     * release values as normal since they are on the top of the heap
	     * size = n1 + n1 - unused_size
	     */

	    *ks = make_pos_bignum_header(unused_size - 1);
	    HRelease(BIF_P, vs + unused_size, vs);
	}

	mp_new->size = n1 + n2 - unused_size;
	*thp = make_arityval(n1 + n2 - unused_size);

	BIF_RET(make_map(mp_new));
    }
    BIF_ERROR(BIF_P, BADARG);
}
/* maps:new/2
 */

BIF_RETTYPE maps_new_0(BIF_ALIST_0) {
    Eterm* hp;
    Eterm tup;
    map_t *mp;

    hp    = HAlloc(BIF_P, (MAP_HEADER_SIZE + 1));
    tup   = make_tuple(hp);
    *hp++ = make_arityval(0);

    mp    = (map_t*)hp;
    mp->thing_word = MAP_HEADER;
    mp->size = 0;
    mp->keys = tup;

    BIF_RET(make_map(mp));
}

/* maps:put/3 */

BIF_RETTYPE maps_put_3(BIF_ALIST_3) {
    if (is_map(BIF_ARG_3) || is_hashmap(BIF_ARG_3)) {
	BIF_RET(erts_maps_put(BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3));
    }
    BIF_ERROR(BIF_P, BADARG);
}

/* maps:remove/3 */

int erts_maps_remove(Process *p, Eterm key, Eterm map, Eterm *res) {
    Uint32 hx;
    if (is_map(map)) {
	Sint n;
	Uint need;
	Eterm *hp_start;
	Eterm *thp, *mhp;
	Eterm *ks, *vs, tup;
	map_t *mp = (map_t*)map_val(map);

	n = map_get_size(mp);

	if (n == 0) {
	    *res = map;
	    return 1;
	}

	ks = map_get_keys(mp);
	vs = map_get_values(mp);

	/* Assume key exists.
	 * Release allocated if it didn't.
	 * Allocate key tuple first.
	 */

	need   = n + 1 - 1 + 3 + n - 1; /* tuple - 1 + map - 1 */
	hp_start = HAlloc(p, need);
	thp    = hp_start;
	mhp    = thp + n;               /* offset with tuple heap size */

	tup    = make_tuple(thp);
	*thp++ = make_arityval(n - 1);

	*res   = make_map(mhp);
	*mhp++ = MAP_HEADER;
	*mhp++ = n - 1;
	*mhp++ = tup;

	if (is_immed(key)) {
	    while (1) {
		if (*ks == key) {
		    goto found_key;
		} else if (--n) {
		    *mhp++ = *vs++;
		    *thp++ = *ks++;
		} else
		    break;
	    }
	} else {
	    while(1) {
		if (EQ(*ks, key)) {
		    goto found_key;
		} else if (--n) {
		    *mhp++ = *vs++;
		    *thp++ = *ks++;
		} else
		    break;
	    }
	}

	/* Not found, remove allocated memory
	 * and return previous map.
	 */
	HRelease(p, hp_start + need, hp_start);

	*res = map;
	return 1;

found_key:
	/* Copy rest of keys and values */
	if (--n) {
	    sys_memcpy(mhp, vs+1, n*sizeof(Eterm));
	    sys_memcpy(thp, ks+1, n*sizeof(Eterm));
	}
	return 1;
    }
    ASSERT(is_hashmap(map));
    hx = hashmap_make_hash(key);
    *res = hashmap_delete(p, hx, key, map);
    return 1;
}

BIF_RETTYPE maps_remove_2(BIF_ALIST_2) {
    if (is_map(BIF_ARG_2) || is_hashmap(BIF_ARG_2)) {
	Eterm res;
	if (erts_maps_remove(BIF_P, BIF_ARG_1, BIF_ARG_2, &res)) {
	    BIF_RET(res);
	}
    }
    BIF_ERROR(BIF_P, BADARG);
}

int erts_maps_update(Process *p, Eterm key, Eterm value, Eterm map, Eterm *res) {
    Uint32 hx;
    if (is_map(map)) {
	Sint n,i;
	Eterm* hp,*shp;
	Eterm *ks,*vs;
	map_t *mp = (map_t*)map_val(map);

	if ((n = map_get_size(mp)) == 0) {
	    return 0;
	}

	ks  = map_get_keys(mp);
	vs  = map_get_values(mp);

	/* only allocate for values,
	 * assume key-tuple will be intact
	 */

	hp  = HAlloc(p, MAP_HEADER_SIZE + n);
	shp = hp;
	*hp++ = MAP_HEADER;
	*hp++ = n;
	*hp++ = mp->keys;

	if (is_immed(key)) {
	    for( i = 0; i < n; i ++) {
		if (ks[i] == key) {
		    goto found_key;
		} else {
		    *hp++ = *vs++;
		}
	    }
	} else {
	    for( i = 0; i < n; i ++) {
		if (EQ(ks[i], key)) {
		    goto found_key;
		} else {
		    *hp++ = *vs++;
		}
	    }
	}

	HRelease(p, shp + MAP_HEADER_SIZE + n, shp);
	return 0;

found_key:
	*hp++ = value;
	vs++;
	if (++i < n)
	    sys_memcpy(hp, vs, (n - i)*sizeof(Eterm));
	*res = make_map(shp);
	return 1;
    }

    ASSERT(is_hashmap(map));
    hx = hashmap_make_hash(key);
    *res = hashmap_insert(p, hx, key, value, map, 1);
    if (is_value(*res))
	return 1;

    return 0;
}

Eterm erts_maps_put(Process *p, Eterm key, Eterm value, Eterm map) {
    Uint32 hx;
    Eterm res;
    if (is_map(map)) {
	Sint n,i;
	Sint c = 0;
	Eterm* hp, *shp;
	Eterm *ks, *vs, tup;
	map_t *mp = (map_t*)map_val(map);

	n = map_get_size(mp);

	if (n == 0) {
	    hp    = HAlloc(p, MAP_HEADER_SIZE + 1 + 2);
	    tup   = make_tuple(hp);
	    *hp++ = make_arityval(1);
	    *hp++ = key;
	    res   = make_map(hp);
	    *hp++ = MAP_HEADER;
	    *hp++ = 1;
	    *hp++ = tup;
	    *hp++ = value;

	    return res;
	}

	ks = map_get_keys(mp);
	vs = map_get_values(mp);

	/* only allocate for values,
	 * assume key-tuple will be intact
	 */

	hp  = HAlloc(p, MAP_HEADER_SIZE + n);
	shp = hp; /* save hp, used if optimistic update fails */
	res = make_map(hp);
	*hp++ = MAP_HEADER;
	*hp++ = n;
	*hp++ = mp->keys;

	if (is_immed(key)) {
	    for( i = 0; i < n; i ++) {
		if (ks[i] == key) {
		    *hp++ = value;
		    vs++;
		    c = 1;
		} else {
		    *hp++ = *vs++;
		}
	    }
	} else {
	    for( i = 0; i < n; i ++) {
		if (EQ(ks[i], key)) {
		    *hp++ = value;
		    vs++;
		    c = 1;
		} else {
		    *hp++ = *vs++;
		}
	    }
	}

	if (c)
	    return res;

	/* the map will grow */

	if (n >= MAP_SMALL_MAP_LIMIT) {
	    hxnode_t *hxns;
	    Uint32 sw, hx;
	    Eterm tmp[2];

	    HRelease(p, shp + MAP_HEADER_SIZE + n, shp);
	    hp = HAlloc(p, (2 * (n + 1)));
	    ks = map_get_keys(mp);
	    vs = map_get_values(mp);

	    /* create tmp hx values and leaf ptrs */
	    hxns = (hxnode_t *)erts_alloc(ERTS_ALC_T_TMP, (n + 1) * sizeof(hxnode_t));

	    for (i = 0; i < n; i++) {
		hx = hashmap_restore_hash(tmp,0,ks[i]);
		swizzle32(sw,hx);
		hxns[i].hx   = sw;
		hxns[i].val  = CONS(hp, ks[i], vs[i]); hp += 2;
		hxns[i].skip = 1;
		hxns[i].i    = i;
	    }

	    hx = hashmap_restore_hash(tmp,0,key);
	    swizzle32(sw,hx);
	    hxns[i].hx   = sw;
	    hxns[i].val  = CONS(hp, key, value); hp += 2;
	    hxns[i].skip = 1;
	    hxns[i].i    = n;

	    res = hashmap_from_unsorted_array(p, hxns, n + 1);

	    erts_free(ERTS_ALC_T_TMP, (void *) hxns);
	    ERTS_VERIFY_UNUSED_TEMP_ALLOC(p);

	    return res;
	}

	/* still a small map. need to make a new tuple,
	 * use old hp since it needs to be recreated anyway. */

	tup    = make_tuple(shp);
	*shp++ = make_arityval(n+1);

	hp    = HAlloc(p, 3 + n + 1);
	res   = make_map(hp);
	*hp++ = MAP_HEADER;
	*hp++ = n + 1;
	*hp++ = tup;

	ks = map_get_keys(mp);
	vs = map_get_values(mp);

	ASSERT(n >= 0);

	/* copy map in order */
	while (n && ((c = CMP_TERM(*ks, key)) < 0)) {
	    *shp++ = *ks++;
	    *hp++  = *vs++;
	    n--;
	}

	*shp++ = key;
	*hp++  = value;

	ASSERT(n >= 0);

	while(n--) {
	    *shp++ = *ks++;
	    *hp++  = *vs++;
	}
	/* we have one word remaining
	 * this will work out fine once we get the size word
	 * in the header.
	 */
	*shp = make_pos_bignum_header(0);
	return res;
    }
    ASSERT(is_hashmap(map));

    hx  = hashmap_make_hash(key);
    res = hashmap_insert(p, hx, key, value, map, 0);
    ASSERT(is_hashmap(res));

    return res;
}

/* maps:update/3 */

BIF_RETTYPE maps_update_3(BIF_ALIST_3) {
    if (is_map(BIF_ARG_3) || is_hashmap(BIF_ARG_3)) {
	Eterm res;
	if (erts_maps_update(BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3, &res)) {
	    BIF_RET(res);
	}
    }
    BIF_ERROR(BIF_P, BADARG);
}


/* maps:values/1 */

BIF_RETTYPE maps_values_1(BIF_ALIST_1) {
    if (is_map(BIF_ARG_1)) {
	Eterm *hp, *vs, res = NIL;
	map_t *mp;
	Uint n;

	mp  = (map_t*)map_val(BIF_ARG_1);
	n   = map_get_size(mp);

	if (n == 0)
	    BIF_RET(res);

	hp  = HAlloc(BIF_P, (2 * n));
	vs  = map_get_values(mp);

	while(n--) {
	    res = CONS(hp, vs[n], res); hp += 2;
	}

	BIF_RET(res);
    } else if (is_hashmap(BIF_ARG_1)) {
	BIF_RET(hashmap_values(BIF_P, BIF_ARG_1));
    }
    BIF_ERROR(BIF_P, BADARG);
}

static Eterm hashmap_to_list(Process *p, Eterm node) {
    DECLARE_WSTACK(stack);
    Eterm *hp, *kv;
    Eterm res = NIL;

    hp  = HAlloc(p, hashmap_size(node) * (2 + 3));
    hashmap_iterator_init(&stack, node);
    while ((kv=hashmap_iterator_next(&stack)) != NULL) {
	Eterm tup = TUPLE2(hp, CAR(kv), CDR(kv));
	hp += 3;
	res = CONS(hp, tup, res);
	hp += 2;
    }
    DESTROY_WSTACK(stack);
    return res;
}

void hashmap_iterator_init(ErtsWStack* s, Eterm node) {
    WSTACK_PUSH((*s), (UWord)THE_NON_VALUE);  /* end marker */
    WSTACK_PUSH((*s), (UWord)node);
}

Eterm* hashmap_iterator_next(ErtsWStack* s) {
    Eterm node, *ptr, hdr;
    Uint32 sz;

    for (;;) {
        ASSERT(!WSTACK_ISEMPTY((*s)));
	node = (Eterm) WSTACK_POP((*s));
        if (is_non_value(node)) {
            return NULL;
        }
        switch (primary_tag(node)) {
        case TAG_PRIMARY_LIST:
            return list_val(node);

        case TAG_PRIMARY_BOXED:
            ptr = boxed_val(node);
            hdr = *ptr;
            ASSERT(is_header(hdr));
            switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
            case HAMT_SUBTAG_HEAD_ARRAY:
                ptr++;
            case HAMT_SUBTAG_NODE_ARRAY:
                ptr++;
                sz = 16;
                while(sz--) { WSTACK_PUSH((*s), (UWord)ptr[sz]); }
                break;
            case HAMT_SUBTAG_HEAD_BITMAP:
                ptr++;
            case HAMT_SUBTAG_NODE_BITMAP:
                sz = hashmap_bitcount(MAP_HEADER_VAL(hdr));
                ASSERT(sz < 17);
                ptr++;
                while(sz--) { WSTACK_PUSH((*s), (UWord)ptr[sz]); }
                break;
            default:
                erl_exit(1, "bad header");
            }
            break;

        default:
            erl_exit(1, "bad hamt node");
	}
    }
}

static const Eterm *hashmap_get(Uint32 hx, Eterm key, Eterm node) {
    Eterm *ptr, hdr;
    Eterm th[2];
    Uint ix,slot, lvl = 0;
    Uint32 hval,bp;

    for (;;) {
	switch(primary_tag(node)) {
	    case TAG_PRIMARY_LIST: /* LEAF NODE [K|V] */
		ptr = list_val(node);
		if (EQ(CAR(ptr), key)) {
		    return &(CDR(ptr));
		}
		return NULL;
	    case TAG_PRIMARY_BOXED:
		ptr = boxed_val(node);
		hdr = *ptr;
		ASSERT(is_header(hdr));

		switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
		    case HAMT_SUBTAG_NODE_ARRAY:
			ix   = hashmap_index(hx);
			hx   = hashmap_shift_hash(th,hx,lvl,key);
			node = ptr[ix+1];
			break;
		    case HAMT_SUBTAG_HEAD_ARRAY:
			ix   = hashmap_index(hx);
			hx   = hashmap_shift_hash(th,hx,lvl,key);
			node = ptr[ix+2];
			break;
		    case HAMT_SUBTAG_NODE_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+1];
			    break;
			}
			/* not occupied */
			return NULL;
		    case HAMT_SUBTAG_HEAD_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+2];
			    break;
			}
			/* not occupied */
			return NULL;
		    default:
			erl_exit(1, "bad header tag %ld\r\n", hdr & _HEADER_MAP_SUBTAG_MASK);
			break;
		}
		break;
	    default:
		erl_exit(1, "bad primary tag %p\r\n", node);
		break;
	}
    }
    return NULL;
}

static Eterm hashmap_insert(Process *p, Uint32 hx, Eterm key, Eterm value,
			    Eterm node, int is_update) {
    Eterm *hp = NULL, *nhp = NULL;
    Eterm *ptr;
    Eterm hdr,res,ckey,fake;
    Eterm th[2];
    Uint32 ix, cix, bp, hval, chx;
    Uint slot, lvl = 0, clvl;
    Uint size = 0, n = 0, update_size = 1;
    DECLARE_ESTACK(stack);

    for (;;) {
	switch(primary_tag(node)) {
	    case TAG_PRIMARY_LIST: /* LEAF NODE [K|V] */
		ptr  = list_val(node);
		ckey = CAR(ptr);
		if (EQ(ckey, key)) {
		    update_size = 0;
		    goto unroll;
		}
		if (is_update) {
		    res = THE_NON_VALUE;
		    goto bail_out;
		}
		goto insert_subnodes;
	    case TAG_PRIMARY_BOXED:
		ptr = boxed_val(node);
		hdr = *ptr;
		ASSERT(is_header(hdr));

		switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
		    case HAMT_SUBTAG_NODE_ARRAY:
			ix    = hashmap_index(hx);
			hx    = hashmap_shift_hash(th,hx,lvl,key);
			size += HAMT_NODE_ARRAY_SZ;
			ESTACK_PUSH2(stack, ix, node);
			node  = ptr[ix+1];
			break;
		    case HAMT_SUBTAG_HEAD_ARRAY:
			ix    = hashmap_index(hx);
			hx    = hashmap_shift_hash(th,hx,lvl,key);
			size += HAMT_HEAD_ARRAY_SZ;
			ESTACK_PUSH2(stack, ix, node);
			node  = ptr[ix+2];
			break;
		    case HAMT_SUBTAG_NODE_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));
			n    = hashmap_bitcount(hval);

			ESTACK_PUSH(stack, n);
			ESTACK_PUSH3(stack, bp, slot, node);

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+1];
			    ASSERT(HAMT_NODE_BITMAP_SZ(n) <= 17);
			    size += HAMT_NODE_BITMAP_SZ(n);
			    break;
			}
			/* not occupied */
			if (is_update) {
			    res = THE_NON_VALUE;
			    goto bail_out;
			}
			size += HAMT_NODE_BITMAP_SZ(n+1);
			goto unroll;
		    case HAMT_SUBTAG_HEAD_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));
			n    = hashmap_bitcount(hval);

			ESTACK_PUSH(stack, n);
			ESTACK_PUSH3(stack, bp, slot, node);

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+2];
			    ASSERT(HAMT_HEAD_BITMAP_SZ(n) <= 18);
			    size += HAMT_HEAD_BITMAP_SZ(n);
			    break;
			}
			/* not occupied */
			if (is_update) {
			    res = THE_NON_VALUE;
			    goto bail_out;
			}
			size += HAMT_HEAD_BITMAP_SZ(n+1);
			goto unroll;
		    default:
			erl_exit(1, "bad header tag %ld\r\n", hdr & _HEADER_MAP_SUBTAG_MASK);
			break;
		}
		break;
	    default:
		erl_exit(1, "bad primary tag %p\r\n", node);
		break;
	}
    }
insert_subnodes:
    clvl  = lvl;
    chx   = hashmap_restore_hash(th,clvl,ckey);
    size += HAMT_NODE_BITMAP_SZ(2);
    ix    = hashmap_index(hx);
    cix   = hashmap_index(chx);

    while (cix == ix) {
	ESTACK_PUSH(stack, 0);
	ESTACK_PUSH3(stack, 1 << ix, 0, MAP_HEADER_HAMT_NODE_BITMAP(0));
	size += HAMT_NODE_BITMAP_SZ(1);
	hx    = hashmap_shift_hash(th,hx,lvl,key);
	chx   = hashmap_shift_hash(th,chx,clvl,ckey);
	ix    = hashmap_index(hx);
	cix   = hashmap_index(chx);
    }
    ESTACK_PUSH3(stack, cix, ix, node);

unroll:
    size += 2;
    hp  = HAlloc(p, size);
    res = CONS(hp, key, value); hp += 2;

    do {
	node = ESTACK_POP(stack);
	switch(primary_tag(node)) {
	    case TAG_PRIMARY_LIST:
		ix   = (Uint32) ESTACK_POP(stack);
		cix  = (Uint32) ESTACK_POP(stack);

		nhp   = hp;
		*hp++ = MAP_HEADER_HAMT_NODE_BITMAP((1 << ix) | (1 << cix));
		if (ix < cix) {
		    *hp++ = res;
		    *hp++ = node;
		} else {
		    *hp++ = node;
		    *hp++ = res;
		}
		res = make_hashmap(nhp);
		break;
	    case TAG_PRIMARY_HEADER:
		/* subnodes, fake it */
		fake = node;
		node = make_boxed(&fake);
	    case TAG_PRIMARY_BOXED:
		ptr = boxed_val(node);
		hdr = *ptr;
		ASSERT(is_header(hdr));

		switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
		    case HAMT_SUBTAG_NODE_ARRAY:
			slot  = (Uint)   ESTACK_POP(stack);
			nhp   = hp;
			n     = HAMT_NODE_ARRAY_SZ;
			while(n--) { *hp++ = *ptr++; }
			nhp[slot+1] = res;
			res = make_hashmap(nhp);
			break;
		    case HAMT_SUBTAG_HEAD_ARRAY:
			slot  = (Uint)   ESTACK_POP(stack);
			nhp   = hp;
			n     = HAMT_HEAD_ARRAY_SZ - 2;
			*hp++ = MAP_HEADER_HAMT_HEAD_ARRAY; ptr++;
			*hp++ = (*ptr++) + update_size;
			while(n--) { *hp++ = *ptr++; }
			nhp[slot+2] = res;
			res = make_hashmap(nhp);
			break;
		    case HAMT_SUBTAG_NODE_BITMAP:
			slot  = (Uint)   ESTACK_POP(stack);
			bp    = (Uint32) ESTACK_POP(stack);
			n     = (Uint32) ESTACK_POP(stack);
			hval  = MAP_HEADER_VAL(hdr);
			nhp   = hp;
			*hp++ = MAP_HEADER_HAMT_NODE_BITMAP(hval | bp); ptr++;

			n -= slot;
			while(slot--) { *hp++ = *ptr++; }
			*hp++ = res;
			if (hval & bp) { ptr++; n--; }
			while(n--) { *hp++ = *ptr++; }

			if ((hval | bp) == 0xffff) {
			    *nhp = make_arityval(16);
			}
			res = make_hashmap(nhp);
			break;
		    case HAMT_SUBTAG_HEAD_BITMAP:
			slot  = (Uint)   ESTACK_POP(stack);
			bp    = (Uint32) ESTACK_POP(stack);
			n     = (Uint32) ESTACK_POP(stack);
			hval  = MAP_HEADER_VAL(hdr);
			nhp   = hp;
			*hp++ = MAP_HEADER_HAMT_HEAD_BITMAP(hval | bp); ptr++;
			*hp++ = (*ptr++) + update_size;

			n -= slot;
			while(slot--) { *hp++ = *ptr++; }
			*hp++ = res;
			if (hval & bp) { ptr++; n--; }
			while(n--) { *hp++ = *ptr++; }

			if ((hval | bp) == 0xffff) {
			    *nhp = MAP_HEADER_HAMT_HEAD_ARRAY;
			}
			res = make_hashmap(nhp);
			break;
		    default:
			erl_exit(1, "bad header tag %x\r\n", hdr & _HEADER_MAP_SUBTAG_MASK);
			break;
		}
		break;
	    default:
		erl_exit(1, "bad primary tag %x\r\n", primary_tag(node));
		break;
	}

    } while(!ESTACK_ISEMPTY(stack));

bail_out:
    DESTROY_ESTACK(stack);
    ERTS_VERIFY_UNUSED_TEMP_ALLOC(p);
    ERTS_HOLE_CHECK(p);
    return res;
}

static Eterm hashmap_keys(Process* p, Eterm node) {
    DECLARE_WSTACK(stack);
    hashmap_head_t* root;
    Eterm *hp, *kv;
    Eterm res = NIL;

    root = (hashmap_head_t*) boxed_val(node);
    hp  = HAlloc(p, root->size * 2);
    hashmap_iterator_init(&stack, node);
    while ((kv=hashmap_iterator_next(&stack)) != NULL) {
	res = CONS(hp, CAR(kv), res);
	hp += 2;
    }
    DESTROY_WSTACK(stack);
    return res;
}

static Eterm hashmap_values(Process* p, Eterm node) {
    DECLARE_WSTACK(stack);
    hashmap_head_t* root;
    Eterm *hp, *kv;
    Eterm res = NIL;

    root = (hashmap_head_t*) boxed_val(node);
    hp  = HAlloc(p, root->size * 2);
    hashmap_iterator_init(&stack, node);
    while ((kv=hashmap_iterator_next(&stack)) != NULL) {
	res = CONS(hp, CDR(kv), res);
	hp += 2;
    }
    DESTROY_WSTACK(stack);
    return res;
}

static Eterm hashmap_delete(Process *p, Uint32 hx, Eterm key, Eterm map) {
    Eterm *hp = NULL, *nhp = NULL, *hp_end = NULL;
    Eterm th[2];
    Eterm *ptr;
    Eterm hdr, res = map, node = map;
    Uint32 ix, bp, hval;
    Uint slot, lvl = 0;
    Uint size = 0, n = 0;
    DECLARE_ESTACK(stack);

    for (;;) {
	switch(primary_tag(node)) {
	    case TAG_PRIMARY_LIST:
		if (EQ(CAR(list_val(node)), key)) {
		    goto unroll;
		}
		goto not_found;
	    case TAG_PRIMARY_BOXED:
		ptr = boxed_val(node);
		hdr = *ptr;
		ASSERT(is_header(hdr));

		switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
		    case HAMT_SUBTAG_NODE_ARRAY:
			ix    = hashmap_index(hx);
			hx    = hashmap_shift_hash(th,hx,lvl,key);
			size += HAMT_NODE_ARRAY_SZ;
			ESTACK_PUSH2(stack, ix, node);
			node  = ptr[ix+1];
			break;
		    case HAMT_SUBTAG_HEAD_ARRAY:
			ix    = hashmap_index(hx);
			hx    = hashmap_shift_hash(th,hx,lvl,key);
			size += HAMT_HEAD_ARRAY_SZ;
			ESTACK_PUSH2(stack, ix, node);
			node  = ptr[ix+2];
			break;
		    case HAMT_SUBTAG_NODE_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));
			n    = hashmap_bitcount(hval);

			ESTACK_PUSH(stack, n);
			ESTACK_PUSH3(stack, bp, slot, node);

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+1];
			    ASSERT(HAMT_NODE_BITMAP_SZ(n) <= 17);
			    size += HAMT_NODE_BITMAP_SZ(n);
			    break;
			}
			/* not occupied */
			goto not_found;
		    case HAMT_SUBTAG_HEAD_BITMAP:
			hval = MAP_HEADER_VAL(hdr);
			ix   = hashmap_index(hx);
			bp   = 1 << ix;
			slot = hashmap_bitcount(hval & (bp - 1));
			n    = hashmap_bitcount(hval);

			ESTACK_PUSH(stack, n);
			ESTACK_PUSH3(stack, bp, slot, node);

			/* occupied */
			if (bp & hval) {
			    hx    = hashmap_shift_hash(th,hx,lvl,key);
			    node  = ptr[slot+2];
			    ASSERT(HAMT_HEAD_BITMAP_SZ(n) <= 18);
			    size += HAMT_HEAD_BITMAP_SZ(n);
			    break;
			}
			/* not occupied */
			goto not_found;
		    default:
			erl_exit(1, "bad header tag %ld\r\n", hdr & _HEADER_MAP_SUBTAG_MASK);
			break;
		}
		break;
	    default:
		erl_exit(1, "bad primary tag %p\r\n", node);
		break;
	}
    }

unroll:
    /* the size is bounded and atleast one less than the previous size */
    size -= 1;
    n     = hashmap_size(map) - 1;

    if (n <= MAP_SMALL_MAP_LIMIT) {
	DECLARE_WSTACK(wstack);
	Eterm *kv, *ks, *vs;
	map_t *mp;
	Eterm keys;

	DESTROY_ESTACK(stack);

	/* build flat structure */
	hp    = HAlloc(p, 3 + 1 + (2 * n));
	keys  = make_tuple(hp);
	*hp++ = make_arityval(n);
	ks    = hp;
	hp   += n;
	mp    = (map_t*)hp;
	hp   += MAP_HEADER_SIZE;
	vs    = hp;

	mp->thing_word = MAP_HEADER;
	mp->size = n;
	mp->keys = keys;

	hashmap_iterator_init(&wstack, map);

	while ((kv=hashmap_iterator_next(&wstack)) != NULL) {
	    if (EQ(CAR(kv),key))
		continue;
	    *ks++ = CAR(kv);
	    *vs++ = CDR(kv);
	}

	/* it cannot have multiple keys */
	erts_validate_and_sort_map(mp);

	DESTROY_WSTACK(wstack);
	return make_map(mp);
    }

    hp     = HAlloc(p, size);
    hp_end = hp + size;
    res    = THE_NON_VALUE;

    do {
	node = ESTACK_POP(stack);

	/* all nodes are things */
	ptr = boxed_val(node);
	hdr = *ptr;
	ASSERT(is_header(hdr));

	switch(hdr & _HEADER_MAP_SUBTAG_MASK) {
	    case HAMT_SUBTAG_NODE_ARRAY:
		ix  = (Uint) ESTACK_POP(stack);
		nhp = hp;
		if (res == THE_NON_VALUE) {
		    *hp++ = MAP_HEADER_HAMT_NODE_BITMAP(0xffff ^ (1 << ix)); ptr++;
		    n     = 16;
		    n    -= ix;
		    while(ix--) { *hp++ = *ptr++; }
		    ptr++; n--;
		    while(n--) { *hp++ = *ptr++; }
		    res = make_hashmap(nhp);
		} else {
		    n = HAMT_NODE_ARRAY_SZ;
		    while(n--) { *hp++ = *ptr++; }
		    nhp[ix+1] = res;
		    res = make_hashmap(nhp);
		}
		break;
	    case HAMT_SUBTAG_HEAD_ARRAY:
		ix  = (Uint) ESTACK_POP(stack);
		nhp = hp;
		if (res == THE_NON_VALUE) {
		    n     = 16;
		    n    -= ix;
		    *hp++ = MAP_HEADER_HAMT_HEAD_BITMAP(0xffff ^ (1 << ix)); ptr++;
		    *hp++ = (*ptr++) - 1;
		    while(ix--) { *hp++ = *ptr++; }
		    ptr++; n--;
		    while(n--) { *hp++ = *ptr++; }
		    res = make_hashmap(nhp);
		} else {
		    n     = 16;
		    *hp++ = MAP_HEADER_HAMT_HEAD_ARRAY; ptr++;
		    *hp++ = (*ptr++) - 1;
		    while(n--) { *hp++ = *ptr++; }
		    nhp[ix+2] = res;
		    res = make_hashmap(nhp);
		}
		break;
	    case HAMT_SUBTAG_NODE_BITMAP:
		slot = (Uint)   ESTACK_POP(stack);
		bp   = (Uint32) ESTACK_POP(stack);
		n    = (Uint32) ESTACK_POP(stack);
		nhp  = hp;

		/* bitmap change matrix
		 * res | none    leaf    bitmap
		 * ----------------------------
		 * n=1 | remove  remove  keep
		 * n=2 | other   keep    keep
		 * n>2 | shrink  keep    keep
		 *
		 * other: (remember, n is 2)
		 *   shrink if the other bitmap value is a bitmap node
		 *   remove if the other bitmap value is a leaf
		 *
		 * remove:
		 *   this bitmap node is removed, res is moved up in tree (could be none)
		 *   this is a special case of shrink
		 *
		 * keep:
		 *   the current path index is still used down in the tree, need to keep it
		 *   copy as usual with the updated res
		 *
		 * shrink:
		 *   the current path index is no longer used down in the tree, remove it (shrink)
		 */
		if (res == THE_NON_VALUE) {
		    if (n == 1) {
			break;
		    } else if (n == 2) {
			if (slot == 0) {
			    ix = 2; /* off by one 'cause hdr */
			} else {
			    ix = 1; /* off by one 'cause hdr */
			}
			if (primary_tag(ptr[ix]) == TAG_PRIMARY_LIST) {
			    res = ptr[ix];
			} else {
			    hval  = MAP_HEADER_VAL(hdr);
			    *hp++ = MAP_HEADER_HAMT_NODE_BITMAP(hval ^ bp);
			    *hp++ = ptr[ix];
			    res = make_hashmap(nhp);
			}
		    } else {
			/* n > 2 */
			hval  = MAP_HEADER_VAL(hdr);
			*hp++ = MAP_HEADER_HAMT_NODE_BITMAP(hval ^ bp); ptr++;
			n    -= slot;
			while(slot--) { *hp++ = *ptr++; }
			ptr++; n--;
			while(n--) { *hp++ = *ptr++; }
			res = make_hashmap(nhp);
		    }
		} else if (primary_tag(res) == TAG_PRIMARY_LIST && n == 1) {
		    break;
		} else {
		    /* res is bitmap or leaf && n > 1, keep */
		    n    -= slot;
		    *hp++ = *ptr++;
		    while(slot--) { *hp++ = *ptr++; }
		    *hp++ = res;
		    ptr++; n--;
		    while(n--) { *hp++ = *ptr++; }
		    res = make_hashmap(nhp);
		}
		break;
	    case HAMT_SUBTAG_HEAD_BITMAP:
		slot = (Uint)   ESTACK_POP(stack);
		bp   = (Uint32) ESTACK_POP(stack);
		n    = (Uint32) ESTACK_POP(stack);
		nhp  = hp;

		if (res != THE_NON_VALUE) {
		    *hp++ = *ptr++;
		    *hp++ = (*ptr++) - 1;
		    n    -= slot;
		    while(slot--) { *hp++ = *ptr++; }
		    *hp++ = res;
		    ptr++; n--;
		    while(n--) { *hp++ = *ptr++; }
		} else {
		    hval  = MAP_HEADER_VAL(hdr);
		    *hp++ = MAP_HEADER_HAMT_HEAD_BITMAP(hval ^ bp); ptr++;
		    *hp++ = (*ptr++) - 1;
		    n    -= slot;
		    while(slot--) { *hp++ = *ptr++; }
		    ptr++; n--;
		    while(n--) { *hp++ = *ptr++; }
		}
		res = make_hashmap(nhp);
		break;
	    default:
		erl_exit(1, "bad header tag %x\r\n", hdr & _HEADER_MAP_SUBTAG_MASK);
		break;
	}
    } while(!ESTACK_ISEMPTY(stack));
    HRelease(p, hp_end, hp);
not_found:
    DESTROY_ESTACK(stack);
    ERTS_VERIFY_UNUSED_TEMP_ALLOC(p);
    ERTS_HOLE_CHECK(p);
    return res;
}


int erts_validate_and_sort_map(map_t* mp)
{
    Eterm *ks  = map_get_keys(mp);
    Eterm *vs  = map_get_values(mp);
    Uint   sz  = map_get_size(mp);
    Uint   ix,jx;
    Eterm  tmp;
    int c;

    /* sort */

    for (ix = 1; ix < sz; ix++) {
	jx = ix;
	while( jx > 0 && (c = CMP_TERM(ks[jx],ks[jx-1])) <= 0 ) {
	    /* identical key -> error */
	    if (c == 0) return 0;

	    tmp = ks[jx];
	    ks[jx] = ks[jx - 1];
	    ks[jx - 1] = tmp;

	    tmp = vs[jx];
	    vs[jx] = vs[jx - 1];
	    vs[jx - 1] = tmp;

	    jx--;
	}
    }
    return 1;
}

/*
 * erts_internal:map_to_tuple_keys/1
 *
 * Used in erts_debug:size/1
 */

BIF_RETTYPE erts_internal_map_to_tuple_keys_1(BIF_ALIST_1) {
    if (is_map(BIF_ARG_1)) {
	map_t *mp = (map_t*)map_val(BIF_ARG_1);
	BIF_RET(mp->keys);
    }
    BIF_ERROR(BIF_P, BADARG);
}