8000 Reduce HT_MAX_SIZE to account for the max load factor of 0.5 by arnaud-lb · Pull Request #10242 · php/php-src · GitHub
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Reduce HT_MAX_SIZE to account for the max load factor of 0.5 #10242

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Merged
merged 3 commits into from
Jan 13, 2023
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Reduce HT_MAX_SIZE to account for the max load factor of 0.5 #10242

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0a654fd
Reduce HT_MAX_SIZE to account for the max load factor of 0.5
arnaud-lb Jan 6, 2023
2465dfa
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arnaud-lb Jan 7, 2023
1772783
Avoid overflow when nTableMask is (uint32_t)INT32_MAX+1
arnaud-lb Jan 7, 2023
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@arnaud-lb
arnaud-lb committed Jan 7, 2023
commit 2465dfa1e2af1c49e33d78a8b33fc786d7f2ccb8
9 changes: 8 additions & 1 deletion Zend/zend_types.h
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Expand Up @@ -400,8 +400,15 @@ struct _zend_array {
#define HT_MIN_MASK ((uint32_t) -2)
#define HT_MIN_SIZE 8

/* HT_MAX_SIZE is chosen to satisfy the following constraints:
* - HT_SIZE_TO_MASK(HT_MAX_SIZE) != 0
* - HT_SIZE_EX(HT_MAX_SIZE, HT_SIZE_TO_MASK(HT_MAX_SIZE)) does not overflow or
* wrapparound, and is <= the addressable space size
* - HT_MAX_SIZE must be a power of two:
* (nTableSize<HT_MAX_SIZE ? nTableSize+nTableSize : nTableSize) <= HT_MAX_SIZE
*/
#if SIZEOF_SIZE_T == 4
# define HT_MAX_SIZE 0x02000000 /* small enough to avoid overflow checks */
# define HT_MAX_SIZE 0x02000000
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This is SSIZE_MAX/(sizeof(Bucket)+2*sizeof(uint32_t)) (0x3ffffff) rounded down to the closest power of two

# define HT_HASH_TO_BUCKET_EX(data, idx) \
((Bucket*)((char*)(data) + (idx)))
# define HT_IDX_TO_HASH(idx) \
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