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gh-122854: Add Py_HashBuffer() function (#122855)

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Victor Stinner 2024-08-30 17:42:27 +02:00 • committed by GitHub
parent 3d60dfbe17
commit d8e69b2c1b
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17 changed files with 80 additions and 25 deletions
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15
Python/pyhash.c
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@ -22,7 +22,7 @@ extern PyHash_FuncDef PyHash_Func;
static PyHash_FuncDef PyHash_Func;
#endif
/* Count _Py_HashBytes() calls */
/* Count Py_HashBuffer() calls */
#ifdef Py_HASH_STATS
#define Py_HASH_STATS_MAX 32
static Py_ssize_t hashstats[Py_HASH_STATS_MAX + 1] = {0};
@ -146,9 +146,8 @@ PyObject_GenericHash(PyObject *obj)
}
Py_hash_t
_Py_HashBytes(const void *src, Py_ssize_t len)
Py_HashBuffer(const void *ptr, Py_ssize_t len)
{
Py_hash_t x;
/*
We make the hash of the empty string be 0, rather than using
(prefix ^ suffix), since this slightly obfuscates the hash secret
@ -161,11 +160,12 @@ _Py_HashBytes(const void *src, Py_ssize_t len)
hashstats[(len <= Py_HASH_STATS_MAX) ? len : 0]++;
#endif
Py_hash_t x;
#if Py_HASH_CUTOFF > 0
if (len < Py_HASH_CUTOFF) {
/* Optimize hashing of very small strings with inline DJBX33A. */
Py_uhash_t hash;
const unsigned char *p = src;
const unsigned char *p = ptr;
hash = 5381; /* DJBX33A starts with 5381 */
switch(len) {
@ -186,10 +186,13 @@ _Py_HashBytes(const void *src, Py_ssize_t len)
}
else
#endif /* Py_HASH_CUTOFF */
x = PyHash_Func.hash(src, len);
{
x = PyHash_Func.hash(ptr, len);
}
if (x == -1)
if (x == -1) {
return -2;
}
return x;
}