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/**
* ***** BEGIN GPL LICENSE BLOCK *****
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The Original Code is Copyright (C) 2008 Blender Foundation.
* All rights reserved.
*
* The Original Code is: all of this file.
*
* Contributor(s): Joseph Eagar.
*
* ***** END GPL LICENSE BLOCK *****
*/
#ifndef BLI_SMALLHASH_H
#define BLI_SMALLHASH_H
/*******a light stack-friendly hash library******
* (it uses stack space for smallish hash tables) */
/*based on a doubling non-chaining approach */
#include "MEM_guardedalloc.h"
#include "BLO_sys_types.h"
#include "BLI_utildefines.h"
extern unsigned int hashsizes[];
#define NONHASH -25436536
typedef struct entry {intptr_t key; void *val;} entry;
#define SMSTACKSIZE 521
typedef struct SmallHash {
entry *table, _stacktable[SMSTACKSIZE], _copytable[SMSTACKSIZE];
entry *stacktable, *copytable;
int used;
int curhash;
int size;
} SmallHash;
/*CELL_UNUSED means this cell is inside a key series, while CELL_FREE
means this cell terminates a key series.
no chance of anyone shoving INT32_MAX-2 into a *val pointer, I
imagine. hopefully. */
#define CELL_UNUSED ((void*)0x7FFFFFFF)
#define CELL_FREE ((void*)0x7FFFFFFD)
#define NONZERO(n) ((n) + !(n))
#define HASHNEXT(h, hoff) ABS(((h) + ((hoff=NONZERO(hoff*2)+1), hoff)))
BM_INLINE void BLI_smallhash_init(SmallHash *hash)
{
int i;
memset(hash, 0, sizeof(*hash));
hash->table = hash->_stacktable;
hash->curhash = 2;
hash->size = hashsizes[hash->curhash];
hash->copytable = hash->_copytable;
hash->stacktable = hash->_stacktable;
for (i=0; i<hash->size; i++) {
hash->table[i].val = CELL_FREE;
}
}
/*NOTE: does *not* free *hash itself! only the direct data!*/
BM_INLINE void BLI_smallhash_release(SmallHash *hash)
{
if (!hash)
return;
if (hash->table != hash->stacktable)
MEM_freeN(hash->table);
}
BM_INLINE void BLI_smallhash_insert(SmallHash *hash, intptr_t key, void *item)
{
int h, hoff=1;
key = ABS(key);
if (hash->size < hash->used*3) {
int newsize = hashsizes[++hash->curhash];
entry *tmp;
int i = 0;
if (hash->table != hash->stacktable || newsize > SMSTACKSIZE) {
tmp = MEM_callocN(sizeof(*hash->table)*newsize, "new hashkeys");
} else {
SWAP(entry*, hash->stacktable, hash->copytable);
tmp = hash->stacktable;
}
SWAP(entry*, tmp, hash->table);
hash->size = newsize;
for (i=0; i<hash->size; i++) {
hash->table[i].val = CELL_FREE;
}
for (i=0; i<hashsizes[hash->curhash-1]; i++) {
if (ELEM(tmp[i].val, CELL_UNUSED, CELL_FREE))
continue;
h = tmp[i].key; hoff = 1;
while (!ELEM(hash->table[h % newsize].val, CELL_UNUSED, CELL_FREE))
h = HASHNEXT(h, hoff);
h %= newsize;
hash->table[h].key = tmp[i].key;
hash->table[h].val = tmp[i].val;
}
if (tmp != hash->stacktable && tmp != hash->copytable) {
MEM_freeN(tmp);
}
}
h = key; hoff = 1;
while (!ELEM(hash->table[h % hash->size].val, CELL_UNUSED, CELL_FREE))
h = HASHNEXT(h, hoff);
h %= hash->size;
hash->table[h].key = key;
hash->table[h].val = item;
hash->used++;
}
BM_INLINE void BLI_smallhash_remove(SmallHash *hash, intptr_t key)
{
int h, hoff=1;
key = ABS(key);
h = key;
while (hash->table[h % hash->size].key != key
|| hash->table[h % hash->size].val == CELL_UNUSED)
{
if (hash->table[h % hash->size].val == CELL_FREE)
return;
h = HASHNEXT(h, hoff);
}
h %= hash->size;
hash->table[h].key = 0;
hash->table[h].val = CELL_UNUSED;
}
BM_INLINE void *BLI_smallhash_lookup(SmallHash *hash, intptr_t key)
{
int h, hoff=1;
key = ABS(key);
h = key;
if (!hash->table)
return NULL;
while (hash->table[h % hash->size].key != key
|| hash->table[h % hash->size].val == CELL_UNUSED)
{
if (hash->table[h % hash->size].val == CELL_FREE)
return NULL;
h = HASHNEXT(h, hoff);
}
return hash->table[h % hash->size].val;
}
BM_INLINE int BLI_smallhash_haskey(SmallHash *hash, intptr_t key)
{
int h = ABS(key), hoff=1;
key = ABS(key);
if (!hash->table)
return 0;
while (hash->table[h % hash->size].key != key
|| hash->table[h % hash->size].val == CELL_UNUSED)
{
if (hash->table[h % hash->size].val == CELL_FREE)
return 0;
h = HASHNEXT(h, hoff);
}
return 1;
}
BM_INLINE int BLI_smallhash_count(SmallHash *hash)
{
return hash->used;
}
#endif // BLI_SMALLHASH_H
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