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Remove unused cityhash32 code

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This commit is contained in:
Lucas S. Vieira 2024-07-22 02:19:58 -03:00
parent dff43d7654
commit d730a6a119
1 changed files with 0 additions and 97 deletions
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97
src/util.c
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@ -118,100 +118,3 @@ adler32(const char *s)
}
return (b << 16) | a;
}
/* cityhash32 */
#define ROTATE32(v, n) (n == 0 ? v : ((v >> n) | (v << (32 - n))))
// This macro expects a big endian value, which we already have
#define FETCH32(p) ((uint32_t)(*p))
#define MAGIC_C1 0xcc9e2d51
#define MAGIC_C2 0x1b873593
uint32_t
_ch32_mur(uint32_t a, uint32_t h)
{
a *= MAGIC_C1;
a = ROTATE32(a, 17);
a *= MAGIC_C2;
h ^= a;
h = ROTATE32(h, 19);
return h * 5 + 0xe6546b64;
}
uint32_t
_ch32_fmix(uint32_t h)
{
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
uint32_t
_ch32_0_4(const char *s, size_t len)
{
uint32_t b = 0, c = 9;
for(size_t i = 0; i < len; i++) {
int8_t v = (int8_t)s[i];
b = b * MAGIC_C1 + ((uint32_t)v);
c ^= b;
}
return _ch32_fmix(_ch32_mur(b, _ch32_mur((uint32_t)len, c)));
}
uint32_t
_ch32_5_12(const char *s, size_t len)
{
uint32_t
a = (uint32_t)len,
b = a * 5,
c = 9,
d = b;
a += FETCH32(s);
b += FETCH32(s + len - 4);
c += FETCH32(s + ((len >> 1) & 4));
return _ch32_fmix(_ch32_mur(c, _ch32_mur(b, _ch32_mur(a, d))));
}
uint32_t
_ch32_13_24(const char *s, size_t len)
{
uint32_t
a = FETCH32(s - 4 + (len >> 1)),
b = FETCH32(s + 4),
c = FETCH32(s + len - 8),
d = FETCH32(s + (len >> 1)),
e = FETCH32(s),
f = FETCH32(s + len - 4),
h = (uint32_t)len;
return _ch32_fmix(
_ch32_mur(
f,
_ch32_mur(
e,
_ch32_mur(
d,
_ch32_mur(
c,
_ch32_mur(
b,
_ch32_mur(a, h)))))));
}
// Perform cityhash32 on a string. Notice that this quick variant
// expects a string below 24 characters.
// Source:
// https://github.com/google/cityhash/blob/f5dc54147fcce12cefd16548c8e760d68ac04226/src/city.cc#L189
uint32_t
cityhash32_sub24(const char *s)
{
size_t len = strlen(s);
len = (len > 24) ? 24 : len;
return (len <= 12)
? (len <= 4 ? _ch32_0_4(s, len) : _ch32_5_12(s, len))
: _ch32_13_24(s, len);
}