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Optimized HashTable size calculation

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This commit is contained in:
Dmitry Stogov
2014-10-23 00:26:32 +04:00
parent 958c6d1c5d
commit 8793aa407e
1 changed files with 18 additions and 17 deletions
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Zend/zend_hash.c
+18 -17
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@@ -99,29 +99,34 @@ static const uint32_t uninitialized_bucket = {INVALID_IDX};
ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC)
{
SET_INCONSISTENT(HT_OK);
/* Use big enough power of 2 */
#ifdef PHP_WIN32
if (nSize >= 0x80000000) {
/* prevent overflow */
ht->nTableSize = 0x80000000;
} else if (nSize <= 8) {
ht->nTableSize = 8;
} else {
#ifdef PHP_WIN32
ht->nTableSize = 1U << __lzcnt(nSize);
if (ht->nTableSize < nSize) {
ht->nTableSize <<= 1;
}
#else
uint32_t i = 4;
while ((1U << i) < nSize) {
i++;
}
ht->nTableSize = 1 << i;
#endif
}
#else
/* size should be between 8 and 0x80000000 */
nSize = (nSize <= 8 ? 8 : (nSize >= 0x80000000 ? 0x80000000 : nSize));
# if defined(__GNUC__)
ht->nTableSize = 0x2 << (__builtin_clz(nSize - 1) ^ 0x1f);
# else
nSize -= 1;
nSize |= (nSize >> 1);
nSize |= (nSize >> 2);
nSize |= (nSize >> 4);
nSize |= (nSize >> 8);
nSize |= (nSize >> 16);
ht->nTableSize = nSize + 1;
# endif
#endif
ht->nTableMask = 0; /* 0 means that ht->arBuckets is uninitialized */
ht->nNumUsed = 0;
@@ -131,11 +136,7 @@ ZEND_API void _zend_hash_init(HashTable *ht, uint32_t nSize, dtor_func_t pDestru
ht->arHash = (uint32_t*)&uninitialized_bucket;
ht->pDestructor = pDestructor;
ht->nInternalPointer = INVALID_IDX;
if (persistent) {
ht->u.flags = HASH_FLAG_PERSISTENT | HASH_FLAG_APPLY_PROTECTION;
} else {
ht->u.flags = HASH_FLAG_APPLY_PROTECTION;
}
ht->u.flags = (persistent ? HASH_FLAG_PERSISTENT : 0) | HASH_FLAG_APPLY_PROTECTION;
}
static void zend_hash_packed_grow(HashTable *ht)