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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Contributor(s): Daniel Dunbar, Joseph Eagar
*
* ***** END GPL LICENSE BLOCK *****
*/
/** \file blender/blenlib/intern/edgehash.c
* \ingroup bli
*
* A general (pointer -> pointer) hash table ADT
*
* \note Based on 'BLI_ghash.c', make sure these stay in sync.
*/
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "MEM_guardedalloc.h"
#include "BLI_utildefines.h"
#include "BLI_edgehash.h"
#include "BLI_mempool.h"
#include "BLI_strict_flags.h"
/**************inlined code************/
static const unsigned int _ehash_hashsizes[] = {
1, 3, 5, 11, 17, 37, 67, 131, 257, 521, 1031, 2053, 4099, 8209,
16411, 32771, 65537, 131101, 262147, 524309, 1048583, 2097169,
4194319, 8388617, 16777259, 33554467, 67108879, 134217757,
268435459
};
/* internal flag to ensure sets values aren't used */
#ifndef NDEBUG
# define EDGEHASH_FLAG_IS_SET (1 << 8)
# define IS_EDGEHASH_ASSERT(eh) BLI_assert((eh->flag & EDGEHASH_FLAG_IS_SET) == 0)
// # define IS_EDGESET_ASSERT(es) BLI_assert((es->flag & EDGEHASH_FLAG_IS_SET) != 0)
#else
# define IS_EDGEHASH_ASSERT(eh)
// # define IS_EDGESET_ASSERT(es)
#endif
/* ensure v0 is smaller */
#define EDGE_ORD(v0, v1) \
if (v0 > v1) { \
SWAP(unsigned int, v0, v1); \
} (void)0
/***/
typedef struct EdgeEntry {
struct EdgeEntry *next;
unsigned int v0, v1;
void *val;
} EdgeEntry;
struct EdgeHash {
EdgeEntry **buckets;
BLI_mempool *epool;
unsigned int nbuckets, nentries;
unsigned int cursize, flag;
};
/* -------------------------------------------------------------------- */
/* EdgeHash API */
/** \name Internal Utility API
* \{ */
/**
* Get the hash for a key.
*/
BLI_INLINE unsigned int edgehash_keyhash(EdgeHash *eh, unsigned int v0, unsigned int v1)
{
BLI_assert(v0 < v1);
return ((v0 * 65) ^ (v1 * 31)) % eh->nbuckets;
}
/**
* Check if the number of items in the GHash is large enough to require more buckets.
*/
BLI_INLINE bool edgehash_test_expand_buckets(const unsigned int nentries, const unsigned int nbuckets)
{
return (nentries > nbuckets * 3);
}
/**
* Expand buckets to the next size up.
*/
BLI_INLINE void edgehash_resize_buckets(EdgeHash *eh, const unsigned int nbuckets)
{
EdgeEntry **buckets_old = eh->buckets;
EdgeEntry **buckets_new;
const unsigned int nbuckets_old = eh->nbuckets;
unsigned int i;
EdgeEntry *e;
BLI_assert(eh->nbuckets != nbuckets);
eh->nbuckets = nbuckets;
buckets_new = MEM_callocN(eh->nbuckets * sizeof(*eh->buckets), "eh buckets");
for (i = 0; i < nbuckets_old; i++) {
EdgeEntry *e_next;
for (e = buckets_old[i]; e; e = e_next) {
const unsigned hash = edgehash_keyhash(eh, e->v0, e->v1);
e_next = e->next;
e->next = buckets_new[hash];
buckets_new[hash] = e;
}
}
eh->buckets = buckets_new;
MEM_freeN(buckets_old);
}
/**
* Increase initial bucket size to match a reserved amount.
*/
BLI_INLINE void edgehash_buckets_reserve(EdgeHash *eh, const unsigned int nentries_reserve)
{
while (edgehash_test_expand_buckets(nentries_reserve, eh->nbuckets)) {
eh->nbuckets = _ehash_hashsizes[++eh->cursize];
}
}
/**
* Internal lookup function.
* Takes a hash argument to avoid calling #ghash_keyhash multiple times.
*/
BLI_INLINE EdgeEntry *edgehash_lookup_entry_ex(EdgeHash *eh, unsigned int v0, unsigned int v1,
const unsigned int hash)
{
EdgeEntry *e;
BLI_assert(v0 < v1);
for (e = eh->buckets[hash]; e; e = e->next) {
if (UNLIKELY(v0 == e->v0 && v1 == e->v1)) {
return e;
}
}
return NULL;
}
/**
* Internal lookup function. Only wraps #edgehash_lookup_entry_ex
*/
BLI_INLINE EdgeEntry *edgehash_lookup_entry(EdgeHash *eh, unsigned int v0, unsigned int v1)
{
unsigned int hash;
EDGE_ORD(v0, v1); /* ensure v0 is smaller */
hash = edgehash_keyhash(eh, v0, v1);
return edgehash_lookup_entry_ex(eh, v0, v1, hash);
}
static EdgeHash *edgehash_new(const char *info,
const unsigned int nentries_reserve,
const unsigned int entry_size)
{
EdgeHash *eh = MEM_mallocN(sizeof(*eh), info);
eh->nbuckets = _ehash_hashsizes[0]; /* eh->cursize */
eh->nentries = 0;
eh->cursize = 0;
eh->flag = 0;
/* if we have reserved the number of elements that this hash will contain */
if (nentries_reserve) {
edgehash_buckets_reserve(eh, nentries_reserve);
}
eh->buckets = MEM_callocN(eh->nbuckets * sizeof(*eh->buckets), "eh buckets");
eh->epool = BLI_mempool_create(entry_size, nentries_reserve, 512, BLI_MEMPOOL_NOP);
return eh;
}
/**
* Internal insert function.
* Takes a hash argument to avoid calling #edgehash_keyhash multiple times.
*/
BLI_INLINE void edgehash_insert_ex(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val,
unsigned int hash)
{
EdgeEntry *e = BLI_mempool_alloc(eh->epool);
BLI_assert((eh->flag & EDGEHASH_FLAG_ALLOW_DUPES) || (BLI_edgehash_haskey(eh, v0, v1) == 0));
IS_EDGEHASH_ASSERT(eh);
/* this helps to track down errors with bad edge data */
BLI_assert(v0 < v1);
BLI_assert(v0 != v1);
e->next = eh->buckets[hash];
e->v0 = v0;
e->v1 = v1;
e->val = val;
eh->buckets[hash] = e;
if (UNLIKELY(edgehash_test_expand_buckets(++eh->nentries, eh->nbuckets))) {
edgehash_resize_buckets(eh, _ehash_hashsizes[++eh->cursize]);
}
}
/**
* Insert function that doesn't set the value (use for EdgeSet)
*/
BLI_INLINE void edgehash_insert_ex_keyonly(EdgeHash *eh, unsigned int v0, unsigned int v1,
unsigned int hash)
{
EdgeEntry *e = BLI_mempool_alloc(eh->epool);
BLI_assert((eh->flag & EDGEHASH_FLAG_ALLOW_DUPES) || (BLI_edgehash_haskey(eh, v0, v1) == 0));
/* this helps to track down errors with bad edge data */
BLI_assert(v0 < v1);
BLI_assert(v0 != v1);
e->next = eh->buckets[hash];
e->v0 = v0;
e->v1 = v1;
/* intentionally leave value unset */
eh->buckets[hash] = e;
if (UNLIKELY(edgehash_test_expand_buckets(++eh->nentries, eh->nbuckets))) {
edgehash_resize_buckets(eh, _ehash_hashsizes[++eh->cursize]);
}
}
BLI_INLINE void edgehash_insert(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val)
{
unsigned int hash;
EDGE_ORD(v0, v1); /* ensure v0 is smaller */
hash = edgehash_keyhash(eh, v0, v1);
edgehash_insert_ex(eh, v0, v1, val, hash);
}
/**
* Run free callbacks for freeing entries.
*/
static void edgehash_free_cb(EdgeHash *eh, EdgeHashFreeFP valfreefp)
{
unsigned int i;
BLI_assert(valfreefp);
for (i = 0; i < eh->nbuckets; i++) {
EdgeEntry *e;
for (e = eh->buckets[i]; e; ) {
EdgeEntry *e_next = e->next;
valfreefp(e->val);
e = e_next;
}
}
}
/** \} */
/** \name Public API
* \{ */
/* Public API */
EdgeHash *BLI_edgehash_new_ex(const char *info,
const unsigned int nentries_reserve)
{
return edgehash_new(info,
nentries_reserve,
sizeof(EdgeEntry));
}
EdgeHash *BLI_edgehash_new(const char *info)
{
return BLI_edgehash_new_ex(info, 0);
}
/**
* Insert edge (\a v0, \a v1) into hash with given value, does
* not check for duplicates.
*/
void BLI_edgehash_insert(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val)
{
edgehash_insert(eh, v0, v1, val);
}
/**
* Assign a new value to a key that may already be in edgehash.
*/
bool BLI_edgehash_reinsert(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val)
{
unsigned int hash;
EdgeEntry *e;
IS_EDGEHASH_ASSERT(eh);
EDGE_ORD(v0, v1); /* ensure v0 is smaller */
hash = edgehash_keyhash(eh, v0, v1);
e = edgehash_lookup_entry_ex(eh, v0, v1, hash);
if (e) {
e->val = val;
return false;
}
else {
edgehash_insert_ex(eh, v0, v1, val, hash);
return true;
}
}
/**
* Return pointer to value for given edge (\a v0, \a v1),
* or NULL if key does not exist in hash.
*/
void **BLI_edgehash_lookup_p(EdgeHash *eh, unsigned int v0, unsigned int v1)
{
EdgeEntry *e = edgehash_lookup_entry(eh, v0, v1);
IS_EDGEHASH_ASSERT(eh);
return e ? &e->val : NULL;
}
/**
* Return value for given edge (\a v0, \a v1), or NULL if
* if key does not exist in hash. (If need exists
* to differentiate between key-value being NULL and
* lack of key then see BLI_edgehash_lookup_p().
*/
void *BLI_edgehash_lookup(EdgeHash *eh, unsigned int v0, unsigned int v1)
{
EdgeEntry *e = edgehash_lookup_entry(eh, v0, v1);
IS_EDGEHASH_ASSERT(eh);
return e ? e->val : NULL;
}
/**
* A version of #BLI_edgehash_lookup which accepts a fallback argument.
*/
void *BLI_edgehash_lookup_default(EdgeHash *eh, unsigned int v0, unsigned int v1, void *val_default)
{
EdgeEntry *e = edgehash_lookup_entry(eh, v0, v1);
IS_EDGEHASH_ASSERT(eh);
return e ? e->val : val_default;
}
/**
* Return boolean true/false if edge (v0,v1) in hash.
*/
bool BLI_edgehash_haskey(EdgeHash *eh, unsigned int v0, unsigned int v1)
{
return (edgehash_lookup_entry(eh, v0, v1) != NULL);
}
/**
* Return number of keys in hash.
*/
int BLI_edgehash_size(EdgeHash *eh)
{
return (int)eh->nentries;
}
/**
* Remove all edges from hash.
*/
void BLI_edgehash_clear_ex(EdgeHash *eh, EdgeHashFreeFP valfreefp,
const unsigned int nentries_reserve)
{
if (valfreefp)
edgehash_free_cb(eh, valfreefp);
eh->nbuckets = _ehash_hashsizes[0]; /* eh->cursize */
eh->nentries = 0;
eh->cursize = 0;
if (nentries_reserve) {
edgehash_buckets_reserve(eh, nentries_reserve);
}
MEM_freeN(eh->buckets);
eh->buckets = MEM_callocN(eh->nbuckets * sizeof(*eh->buckets), "eh buckets");
BLI_mempool_clear_ex(eh->epool, nentries_reserve ? (int)nentries_reserve : -1);
}
void BLI_edgehash_free(EdgeHash *eh, EdgeHashFreeFP valfreefp)
{
BLI_assert((int)eh->nentries == BLI_mempool_count(eh->epool));
if (valfreefp)
edgehash_free_cb(eh, valfreefp);
BLI_mempool_destroy(eh->epool);
MEM_freeN(eh->buckets);
MEM_freeN(eh);
}
void BLI_edgehash_flag_set(EdgeHash *eh, unsigned int flag)
{
eh->flag |= flag;
}
void BLI_edgehash_flag_clear(EdgeHash *eh, unsigned int flag)
{
eh->flag &= ~flag;
}
/** \} */
/* -------------------------------------------------------------------- */
/* EdgeHash Iterator API */
/** \name Iterator API
* \{ */
/**
* Create a new EdgeHashIterator. The hash table must not be mutated
* while the iterator is in use, and the iterator will step exactly
* BLI_edgehash_size(gh) times before becoming done.
*/
EdgeHashIterator *BLI_edgehashIterator_new(EdgeHash *eh)
{
EdgeHashIterator *ehi = MEM_mallocN(sizeof(*ehi), "eh iter");
BLI_edgehashIterator_init(ehi, eh);
return ehi;
}
/**
* Init an already allocated EdgeHashIterator. The hash table must not
* be mutated while the iterator is in use, and the iterator will
* step exactly BLI_edgehash_size(eh) times before becoming done.
*
* \param ehi The EdgeHashIterator to initialize.
* \param eh The EdgeHash to iterate over.
*/
void BLI_edgehashIterator_init(EdgeHashIterator *ehi, EdgeHash *eh)
{
ehi->eh = eh;
ehi->curEntry = NULL;
ehi->curBucket = UINT_MAX; /* wraps to zero */
if (eh->nentries) {
do {
ehi->curBucket++;
if (UNLIKELY(ehi->curBucket == ehi->eh->nbuckets)) {
break;
}
ehi->curEntry = ehi->eh->buckets[ehi->curBucket];
} while (!ehi->curEntry);
}
}
/**
* Steps the iterator to the next index.
*/
void BLI_edgehashIterator_step(EdgeHashIterator *ehi)
{
if (ehi->curEntry) {
ehi->curEntry = ehi->curEntry->next;
while (!ehi->curEntry) {
ehi->curBucket++;
if (UNLIKELY(ehi->curBucket == ehi->eh->nbuckets)) {
break;
}
ehi->curEntry = ehi->eh->buckets[ehi->curBucket];
}
}
}
/**
* Free an EdgeHashIterator.
*/
void BLI_edgehashIterator_free(EdgeHashIterator *ehi)
{
MEM_freeN(ehi);
}
/* inline functions now */
#if 0
/**
* Retrieve the key from an iterator.
*/
void BLI_edgehashIterator_getKey(EdgeHashIterator *ehi, unsigned int *r_v0, unsigned int *r_v1)
{
*r_v0 = ehi->curEntry->v0;
*r_v1 = ehi->curEntry->v1;
}
/**
* Retrieve the value from an iterator.
*/
void *BLI_edgehashIterator_getValue(EdgeHashIterator *ehi)
{
return ehi->curEntry->val;
}
/**
* Retrieve the pointer to the value from an iterator.
*/
void **BLI_edgehashIterator_getValue_p(EdgeHashIterator *ehi)
{
return &ehi->curEntry->val;
}
/**
* Set the value for an iterator.
*/
void BLI_edgehashIterator_setValue(EdgeHashIterator *ehi, void *val)
{
ehi->curEntry->val = val;
}
/**
* Determine if an iterator is done.
*/
bool BLI_edgehashIterator_isDone(EdgeHashIterator *ehi)
{
return (ehi->curEntry == NULL);
}
#endif
/** \} */
/* -------------------------------------------------------------------- */
/* EdgeSet API */
/* Use edgehash API to give 'set' functionality */
/** \name EdgeSet Functions
* \{ */
EdgeSet *BLI_edgeset_new_ex(const char *info,
const unsigned int nentries_reserve)
{
EdgeSet *es = (EdgeSet *)edgehash_new(info,
nentries_reserve,
sizeof(EdgeEntry) - sizeof(void *));
#ifndef NDEBUG
((EdgeHash *)es)->flag |= EDGEHASH_FLAG_IS_SET;
#endif
return es;
}
EdgeSet *BLI_edgeset_new(const char *info)
{
return BLI_edgeset_new_ex(info, 0);
}
int BLI_edgeset_size(EdgeSet *es)
{
return (int)((EdgeHash *)es)->nentries;
}
/**
* Adds the key to the set (no checks for unique keys!).
* Matching #BLI_edgehash_insert
*/
void BLI_edgeset_insert(EdgeSet *es, unsigned int v0, unsigned int v1)
{
unsigned int hash;
EDGE_ORD(v0, v1); /* ensure v0 is smaller */
hash = edgehash_keyhash((EdgeHash *)es, v0, v1);
edgehash_insert_ex_keyonly((EdgeHash *)es, v0, v1, hash);
}
/**
* A version of BLI_edgeset_insert which checks first if the key is in the set.
* \returns true if a new key has been added.
*
* \note EdgeHash has no equivalent to this because typically the value would be different.
*/
bool BLI_edgeset_add(EdgeSet *es, unsigned int v0, unsigned int v1)
{
unsigned int hash;
EdgeEntry *e;
EDGE_ORD(v0, v1); /* ensure v0 is smaller */
hash = edgehash_keyhash((EdgeHash *)es, v0, v1);
e = edgehash_lookup_entry_ex((EdgeHash *)es, v0, v1, hash);
if (e) {
return false;
}
else {
edgehash_insert_ex_keyonly((EdgeHash *)es, v0, v1, hash);
return true;
}
}
bool BLI_edgeset_haskey(EdgeSet *es, unsigned int v0, unsigned int v1)
{
return (edgehash_lookup_entry((EdgeHash *)es, v0, v1) != NULL);
}
void BLI_edgeset_free(EdgeSet *es)
{
BLI_edgehash_free((EdgeHash *)es, NULL);
}
/** \} */
/** \name Debugging & Introspection
* \{ */
#ifdef DEBUG
/**
* Measure how well the hash function performs
* (1.0 is approx as good as random distribution).
*/
double BLI_edgehash_calc_quality(EdgeHash *eh)
{
uint64_t sum = 0;
unsigned int i;
if (eh->nentries == 0)
return -1.0;
for (i = 0; i < eh->nbuckets; i++) {
uint64_t count = 0;
EdgeEntry *e;
for (e = eh->buckets[i]; e; e = e->next) {
count += 1;
}
sum += count * (count + 1);
}
return ((double)sum * (double)eh->nbuckets /
((double)eh->nentries * (eh->nentries + 2 * eh->nbuckets - 1)));
}
double BLI_edgeset_calc_quality(EdgeSet *es)
{
return BLI_edgehash_calc_quality((EdgeHash *)es);
}
#endif
/** \} */
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