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#include "common.h"
namespace {
#include "farmhashsu.cc"
}
namespace farmhashsa {
#if !can_use_sse42
uint32_t Hash32(const char *s, size_t len) {
FARMHASH_DIE_IF_MISCONFIGURED;
return s == NULL ? 0 : len;
}
uint32_t Hash32WithSeed(const char *s, size_t len, uint32_t seed) {
FARMHASH_DIE_IF_MISCONFIGURED;
return seed + Hash32(s, len);
}
#else
#undef Fetch
#define Fetch Fetch32
#undef Rotate
#define Rotate Rotate32
#undef Bswap
#define Bswap Bswap32
// Helpers for data-parallel operations (4x 32-bits).
STATIC_INLINE __m128i Add(__m128i x, __m128i y) { return _mm_add_epi32(x, y); }
STATIC_INLINE __m128i Xor(__m128i x, __m128i y) { return _mm_xor_si128(x, y); }
STATIC_INLINE __m128i Or(__m128i x, __m128i y) { return _mm_or_si128(x, y); }
STATIC_INLINE __m128i Mul(__m128i x, __m128i y) { return _mm_mullo_epi32(x, y); }
STATIC_INLINE __m128i Mul5(__m128i x) { return Add(x, _mm_slli_epi32(x, 2)); }
STATIC_INLINE __m128i Rotate(__m128i x, int c) {
return Or(_mm_slli_epi32(x, c),
_mm_srli_epi32(x, 32 - c));
}
STATIC_INLINE __m128i Rot17(__m128i x) { return Rotate(x, 17); }
STATIC_INLINE __m128i Rot19(__m128i x) { return Rotate(x, 19); }
STATIC_INLINE __m128i Shuffle0321(__m128i x) {
return _mm_shuffle_epi32(x, (0 << 6) + (3 << 4) + (2 << 2) + (1 << 0));
}
uint32_t Hash32(const char *s, size_t len) {
const uint32_t seed = 81;
if (len <= 24) {
return len <= 12 ?
(len <= 4 ?
farmhashmk::Hash32Len0to4(s, len) :
farmhashmk::Hash32Len5to12(s, len)) :
farmhashmk::Hash32Len13to24(s, len);
}
if (len < 40) {
uint32_t a = len, b = seed * c2, c = a + b;
a += Fetch(s + len - 4);
b += Fetch(s + len - 20);
c += Fetch(s + len - 16);
uint32_t d = a;
a = NAMESPACE_FOR_HASH_FUNCTIONS::Rotate32(a, 21);
a = Mur(a, Mur(b, Mur(c, d)));
a += Fetch(s + len - 12);
b += Fetch(s + len - 8);
d += a;
a += d;
b = Mur(b, d) * c2;
a = _mm_crc32_u32(a, b + c);
return farmhashmk::Hash32Len13to24(s, (len + 1) / 2, a) + b;
}
#undef Mulc1
#define Mulc1(x) Mul((x), cc1)
#undef Mulc2
#define Mulc2(x) Mul((x), cc2)
#undef Murk
#define Murk(a, h) \
Add(k, \
Mul5( \
Rot19( \
Xor( \
Mulc2( \
Rot17( \
Mulc1(a))), \
(h)))))
const __m128i cc1 = _mm_set1_epi32(c1);
const __m128i cc2 = _mm_set1_epi32(c2);
__m128i h = _mm_set1_epi32(seed);
__m128i g = _mm_set1_epi32(c1 * seed);
__m128i f = g;
__m128i k = _mm_set1_epi32(0xe6546b64);
if (len < 80) {
__m128i a = Fetch128(s);
__m128i b = Fetch128(s + 16);
__m128i c = Fetch128(s + (len - 15) / 2);
__m128i d = Fetch128(s + len - 32);
__m128i e = Fetch128(s + len - 16);
h = Add(h, a);
g = Add(g, b);
g = Shuffle0321(g);
f = Add(f, c);
__m128i be = Add(b, Mulc1(e));
h = Add(h, f);
f = Add(f, h);
h = Add(Murk(d, h), e);
k = Xor(k, _mm_shuffle_epi8(g, f));
g = Add(Xor(c, g), a);
f = Add(Xor(be, f), d);
k = Add(k, be);
k = Add(k, _mm_shuffle_epi8(f, h));
f = Add(f, g);
g = Add(g, f);
g = Add(_mm_set1_epi32(len), Mulc1(g));
} else {
// len >= 80
// The following is loosely modelled after farmhashmk::Hash32.
size_t iters = (len - 1) / 80;
len -= iters * 80;
#undef Chunk
#define Chunk() do { \
__m128i a = Fetch128(s); \
__m128i b = Fetch128(s + 16); \
__m128i c = Fetch128(s + 32); \
__m128i d = Fetch128(s + 48); \
__m128i e = Fetch128(s + 64); \
h = Add(h, a); \
g = Add(g, b); \
g = Shuffle0321(g); \
f = Add(f, c); \
__m128i be = Add(b, Mulc1(e)); \
h = Add(h, f); \
f = Add(f, h); \
h = Add(Murk(d, h), e); \
k = Xor(k, _mm_shuffle_epi8(g, f)); \
g = Add(Xor(c, g), a); \
f = Add(Xor(be, f), d); \
k = Add(k, be); \
k = Add(k, _mm_shuffle_epi8(f, h)); \
f = Add(f, g); \
g = Add(g, f); \
f = Mulc1(f); \
} while (0)
while (iters-- != 0) {
Chunk();
s += 80;
}
if (len != 0) {
h = Add(h, _mm_set1_epi32(len));
s = s + len - 80;
Chunk();
}
}
g = Shuffle0321(g);
k = Xor(k, g);
f = Mulc1(f);
k = Mulc2(k);
g = Mulc1(g);
h = Mulc2(h);
k = Add(k, _mm_shuffle_epi8(g, f));
h = Add(h, f);
f = Add(f, h);
g = Add(g, k);
k = Add(k, g);
k = Xor(k, _mm_shuffle_epi8(f, h));
__m128i buf[4];
buf[0] = f;
buf[1] = g;
buf[2] = k;
buf[3] = h;
s = reinterpret_cast<char*>(buf);
uint32_t x = Fetch(s);
uint32_t y = Fetch(s+4);
uint32_t z = Fetch(s+8);
x = _mm_crc32_u32(x, Fetch(s+12));
y = _mm_crc32_u32(y, Fetch(s+16));
z = _mm_crc32_u32(z * c1, Fetch(s+20));
x = _mm_crc32_u32(x, Fetch(s+24));
y = _mm_crc32_u32(y * c1, Fetch(s+28));
uint32_t o = y;
z = _mm_crc32_u32(z, Fetch(s+32));
x = _mm_crc32_u32(x * c1, Fetch(s+36));
y = _mm_crc32_u32(y, Fetch(s+40));
z = _mm_crc32_u32(z * c1, Fetch(s+44));
x = _mm_crc32_u32(x, Fetch(s+48));
y = _mm_crc32_u32(y * c1, Fetch(s+52));
z = _mm_crc32_u32(z, Fetch(s+56));
x = _mm_crc32_u32(x, Fetch(s+60));
return (o - x + y - z) * c1;
}
#undef Chunk
#undef Murk
#undef Mulc2
#undef Mulc1
uint32_t Hash32WithSeed(const char *s, size_t len, uint32_t seed) {
if (len <= 24) {
if (len >= 13) return farmhashmk::Hash32Len13to24(s, len, seed * c1);
else if (len >= 5) return farmhashmk::Hash32Len5to12(s, len, seed);
else return farmhashmk::Hash32Len0to4(s, len, seed);
}
uint32_t h = farmhashmk::Hash32Len13to24(s, 24, seed ^ len);
return _mm_crc32_u32(Hash32(s + 24, len - 24) + seed, h);
}
#endif
} // namespace farmhashsa
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