From e8835df9d34b87c31d769913dcf0340d66ab7a1c Mon Sep 17 00:00:00 2001 From: Chris Dyer Date: Thu, 26 Apr 2012 00:06:09 -0400 Subject: mostly implemented rampion optimizer --- utils/city.cc | 467 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 467 insertions(+) create mode 100644 utils/city.cc (limited to 'utils/city.cc') diff --git a/utils/city.cc b/utils/city.cc new file mode 100644 index 00000000..f1301ce4 --- /dev/null +++ b/utils/city.cc @@ -0,0 +1,467 @@ +// Copyright (c) 2011 Google, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. +// +// CityHash, by Geoff Pike and Jyrki Alakuijala +// +// This file provides CityHash64() and related functions. +// +// It's probably possible to create even faster hash functions by +// writing a program that systematically explores some of the space of +// possible hash functions, by using SIMD instructions, or by +// compromising on hash quality. + +#include "config.h" +#include + +#include +#include // for memcpy and memset + +using namespace std; + +static uint64 UNALIGNED_LOAD64(const char *p) { + uint64 result; + memcpy(&result, p, sizeof(result)); + return result; +} + +static uint32 UNALIGNED_LOAD32(const char *p) { + uint32 result; + memcpy(&result, p, sizeof(result)); + return result; +} + +#if !defined(WORDS_BIGENDIAN) + +#define uint32_in_expected_order(x) (x) +#define uint64_in_expected_order(x) (x) + +#else + +#ifdef _MSC_VER +#include +#define bswap_32(x) _byteswap_ulong(x) +#define bswap_64(x) _byteswap_uint64(x) + +#elif defined(__APPLE__) +// Mac OS X / Darwin features +#include +#define bswap_32(x) OSSwapInt32(x) +#define bswap_64(x) OSSwapInt64(x) + +#else +#include +#endif + +#define uint32_in_expected_order(x) (bswap_32(x)) +#define uint64_in_expected_order(x) (bswap_64(x)) + +#endif // WORDS_BIGENDIAN + +#if !defined(LIKELY) +#if HAVE_BUILTIN_EXPECT +#define LIKELY(x) (__builtin_expect(!!(x), 1)) +#else +#define LIKELY(x) (x) +#endif +#endif + +static uint64 Fetch64(const char *p) { + return uint64_in_expected_order(UNALIGNED_LOAD64(p)); +} + +static uint32 Fetch32(const char *p) { + return uint32_in_expected_order(UNALIGNED_LOAD32(p)); +} + +// Some primes between 2^63 and 2^64 for various uses. +static const uint64 k0 = 0xc3a5c85c97cb3127ULL; +static const uint64 k1 = 0xb492b66fbe98f273ULL; +static const uint64 k2 = 0x9ae16a3b2f90404fULL; +static const uint64 k3 = 0xc949d7c7509e6557ULL; + +// Bitwise right rotate. Normally this will compile to a single +// instruction, especially if the shift is a manifest constant. +static uint64 Rotate(uint64 val, int shift) { + // Avoid shifting by 64: doing so yields an undefined result. + return shift == 0 ? val : ((val >> shift) | (val << (64 - shift))); +} + +// Equivalent to Rotate(), but requires the second arg to be non-zero. +// On x86-64, and probably others, it's possible for this to compile +// to a single instruction if both args are already in registers. +static uint64 RotateByAtLeast1(uint64 val, int shift) { + return (val >> shift) | (val << (64 - shift)); +} + +static uint64 ShiftMix(uint64 val) { + return val ^ (val >> 47); +} + +static uint64 HashLen16(uint64 u, uint64 v) { + return Hash128to64(uint128(u, v)); +} + +static uint64 HashLen0to16(const char *s, size_t len) { + if (len > 8) { + uint64 a = Fetch64(s); + uint64 b = Fetch64(s + len - 8); + return HashLen16(a, RotateByAtLeast1(b + len, len)) ^ b; + } + if (len >= 4) { + uint64 a = Fetch32(s); + return HashLen16(len + (a << 3), Fetch32(s + len - 4)); + } + if (len > 0) { + uint8 a = s[0]; + uint8 b = s[len >> 1]; + uint8 c = s[len - 1]; + uint32 y = static_cast(a) + (static_cast(b) << 8); + uint32 z = len + (static_cast(c) << 2); + return ShiftMix(y * k2 ^ z * k3) * k2; + } + return k2; +} + +// This probably works well for 16-byte strings as well, but it may be overkill +// in that case. +static uint64 HashLen17to32(const char *s, size_t len) { + uint64 a = Fetch64(s) * k1; + uint64 b = Fetch64(s + 8); + uint64 c = Fetch64(s + len - 8) * k2; + uint64 d = Fetch64(s + len - 16) * k0; + return HashLen16(Rotate(a - b, 43) + Rotate(c, 30) + d, + a + Rotate(b ^ k3, 20) - c + len); +} + +// Return a 16-byte hash for 48 bytes. Quick and dirty. +// Callers do best to use "random-looking" values for a and b. +static pair WeakHashLen32WithSeeds( + uint64 w, uint64 x, uint64 y, uint64 z, uint64 a, uint64 b) { + a += w; + b = Rotate(b + a + z, 21); + uint64 c = a; + a += x; + a += y; + b += Rotate(a, 44); + return make_pair(a + z, b + c); +} + +// Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty. +static pair WeakHashLen32WithSeeds( + const char* s, uint64 a, uint64 b) { + return WeakHashLen32WithSeeds(Fetch64(s), + Fetch64(s + 8), + Fetch64(s + 16), + Fetch64(s + 24), + a, + b); +} + +// Return an 8-byte hash for 33 to 64 bytes. +static uint64 HashLen33to64(const char *s, size_t len) { + uint64 z = Fetch64(s + 24); + uint64 a = Fetch64(s) + (len + Fetch64(s + len - 16)) * k0; + uint64 b = Rotate(a + z, 52); + uint64 c = Rotate(a, 37); + a += Fetch64(s + 8); + c += Rotate(a, 7); + a += Fetch64(s + 16); + uint64 vf = a + z; + uint64 vs = b + Rotate(a, 31) + c; + a = Fetch64(s + 16) + Fetch64(s + len - 32); + z = Fetch64(s + len - 8); + b = Rotate(a + z, 52); + c = Rotate(a, 37); + a += Fetch64(s + len - 24); + c += Rotate(a, 7); + a += Fetch64(s + len - 16); + uint64 wf = a + z; + uint64 ws = b + Rotate(a, 31) + c; + uint64 r = ShiftMix((vf + ws) * k2 + (wf + vs) * k0); + return ShiftMix(r * k0 + vs) * k2; +} + +uint64 CityHash64(const char *s, size_t len) { + if (len <= 32) { + if (len <= 16) { + return HashLen0to16(s, len); + } else { + return HashLen17to32(s, len); + } + } else if (len <= 64) { + return HashLen33to64(s, len); + } + + // For strings over 64 bytes we hash the end first, and then as we + // loop we keep 56 bytes of state: v, w, x, y, and z. + uint64 x = Fetch64(s + len - 40); + uint64 y = Fetch64(s + len - 16) + Fetch64(s + len - 56); + uint64 z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24)); + pair v = WeakHashLen32WithSeeds(s + len - 64, len, z); + pair w = WeakHashLen32WithSeeds(s + len - 32, y + k1, x); + x = x * k1 + Fetch64(s); + + // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks. + len = (len - 1) & ~static_cast(63); + do { + x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1; + y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1; + x ^= w.second; + y += v.first + Fetch64(s + 40); + z = Rotate(z + w.first, 33) * k1; + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16)); + std::swap(z, x); + s += 64; + len -= 64; + } while (len != 0); + return HashLen16(HashLen16(v.first, w.first) + ShiftMix(y) * k1 + z, + HashLen16(v.second, w.second) + x); +} + +uint64 CityHash64WithSeed(const char *s, size_t len, uint64 seed) { + return CityHash64WithSeeds(s, len, k2, seed); +} + +uint64 CityHash64WithSeeds(const char *s, size_t len, + uint64 seed0, uint64 seed1) { + return HashLen16(CityHash64(s, len) - seed0, seed1); +} + +// A subroutine for CityHash128(). Returns a decent 128-bit hash for strings +// of any length representable in signed long. Based on City and Murmur. +static uint128 CityMurmur(const char *s, size_t len, uint128 seed) { + uint64 a = Uint128Low64(seed); + uint64 b = Uint128High64(seed); + uint64 c = 0; + uint64 d = 0; + signed long l = len - 16; + if (l <= 0) { // len <= 16 + a = ShiftMix(a * k1) * k1; + c = b * k1 + HashLen0to16(s, len); + d = ShiftMix(a + (len >= 8 ? Fetch64(s) : c)); + } else { // len > 16 + c = HashLen16(Fetch64(s + len - 8) + k1, a); + d = HashLen16(b + len, c + Fetch64(s + len - 16)); + a += d; + do { + a ^= ShiftMix(Fetch64(s) * k1) * k1; + a *= k1; + b ^= a; + c ^= ShiftMix(Fetch64(s + 8) * k1) * k1; + c *= k1; + d ^= c; + s += 16; + l -= 16; + } while (l > 0); + } + a = HashLen16(a, c); + b = HashLen16(d, b); + return uint128(a ^ b, HashLen16(b, a)); +} + +uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed) { + if (len < 128) { + return CityMurmur(s, len, seed); + } + + // We expect len >= 128 to be the common case. Keep 56 bytes of state: + // v, w, x, y, and z. + pair v, w; + uint64 x = Uint128Low64(seed); + uint64 y = Uint128High64(seed); + uint64 z = len * k1; + v.first = Rotate(y ^ k1, 49) * k1 + Fetch64(s); + v.second = Rotate(v.first, 42) * k1 + Fetch64(s + 8); + w.first = Rotate(y + z, 35) * k1 + x; + w.second = Rotate(x + Fetch64(s + 88), 53) * k1; + + // This is the same inner loop as CityHash64(), manually unrolled. + do { + x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1; + y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1; + x ^= w.second; + y += v.first + Fetch64(s + 40); + z = Rotate(z + w.first, 33) * k1; + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16)); + std::swap(z, x); + s += 64; + x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1; + y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1; + x ^= w.second; + y += v.first + Fetch64(s + 40); + z = Rotate(z + w.first, 33) * k1; + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16)); + std::swap(z, x); + s += 64; + len -= 128; + } while (LIKELY(len >= 128)); + x += Rotate(v.first + z, 49) * k0; + z += Rotate(w.first, 37) * k0; + // If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s. + for (size_t tail_done = 0; tail_done < len; ) { + tail_done += 32; + y = Rotate(x + y, 42) * k0 + v.second; + w.first += Fetch64(s + len - tail_done + 16); + x = x * k0 + w.first; + z += w.second + Fetch64(s + len - tail_done); + w.second += v.first; + v = WeakHashLen32WithSeeds(s + len - tail_done, v.first + z, v.second); + } + // At this point our 56 bytes of state should contain more than + // enough information for a strong 128-bit hash. We use two + // different 56-byte-to-8-byte hashes to get a 16-byte final result. + x = HashLen16(x, v.first); + y = HashLen16(y + z, w.first); + return uint128(HashLen16(x + v.second, w.second) + y, + HashLen16(x + w.second, y + v.second)); +} + +uint128 CityHash128(const char *s, size_t len) { + if (len >= 16) { + return CityHash128WithSeed(s + 16, + len - 16, + uint128(Fetch64(s) ^ k3, + Fetch64(s + 8))); + } else if (len >= 8) { + return CityHash128WithSeed(NULL, + 0, + uint128(Fetch64(s) ^ (len * k0), + Fetch64(s + len - 8) ^ k1)); + } else { + return CityHash128WithSeed(s, len, uint128(k0, k1)); + } +} + +#ifdef __SSE4_2__ +#include +#include + +// Requires len >= 240. +static void CityHashCrc256Long(const char *s, size_t len, + uint32 seed, uint64 *result) { + uint64 a = Fetch64(s + 56) + k0; + uint64 b = Fetch64(s + 96) + k0; + uint64 c = result[0] = HashLen16(b, len); + uint64 d = result[1] = Fetch64(s + 120) * k0 + len; + uint64 e = Fetch64(s + 184) + seed; + uint64 f = seed; + uint64 g = 0; + uint64 h = 0; + uint64 i = 0; + uint64 j = 0; + uint64 t = c + d; + + // 240 bytes of input per iter. + size_t iters = len / 240; + len -= iters * 240; + do { +#define CHUNK(multiplier, z) \ + { \ + uint64 old_a = a; \ + a = Rotate(b, 41 ^ z) * multiplier + Fetch64(s); \ + b = Rotate(c, 27 ^ z) * multiplier + Fetch64(s + 8); \ + c = Rotate(d, 41 ^ z) * multiplier + Fetch64(s + 16); \ + d = Rotate(e, 33 ^ z) * multiplier + Fetch64(s + 24); \ + e = Rotate(t, 25 ^ z) * multiplier + Fetch64(s + 32); \ + t = old_a; \ + } \ + f = _mm_crc32_u64(f, a); \ + g = _mm_crc32_u64(g, b); \ + h = _mm_crc32_u64(h, c); \ + i = _mm_crc32_u64(i, d); \ + j = _mm_crc32_u64(j, e); \ + s += 40 + + CHUNK(1, 1); CHUNK(k0, 0); + CHUNK(1, 1); CHUNK(k0, 0); + CHUNK(1, 1); CHUNK(k0, 0); + } while (--iters > 0); + + while (len >= 40) { + CHUNK(k0, 0); + len -= 40; + } + if (len > 0) { + s = s + len - 40; + CHUNK(k0, 0); + } + j += i << 32; + a = HashLen16(a, j); + h += g << 32; + b += h; + c = HashLen16(c, f) + i; + d = HashLen16(d, e + result[0]); + j += e; + i += HashLen16(h, t); + e = HashLen16(a, d) + j; + f = HashLen16(b, c) + a; + g = HashLen16(j, i) + c; + result[0] = e + f + g + h; + a = ShiftMix((a + g) * k0) * k0 + b; + result[1] += a + result[0]; + a = ShiftMix(a * k0) * k0 + c; + result[2] = a + result[1]; + a = ShiftMix((a + e) * k0) * k0; + result[3] = a + result[2]; +} + +// Requires len < 240. +static void CityHashCrc256Short(const char *s, size_t len, uint64 *result) { + char buf[240]; + memcpy(buf, s, len); + memset(buf + len, 0, 240 - len); + CityHashCrc256Long(buf, 240, ~static_cast(len), result); +} + +void CityHashCrc256(const char *s, size_t len, uint64 *result) { + if (LIKELY(len >= 240)) { + CityHashCrc256Long(s, len, 0, result); + } else { + CityHashCrc256Short(s, len, result); + } +} + +uint128 CityHashCrc128WithSeed(const char *s, size_t len, uint128 seed) { + if (len <= 900) { + return CityHash128WithSeed(s, len, seed); + } else { + uint64 result[4]; + CityHashCrc256(s, len, result); + uint64 u = Uint128High64(seed) + result[0]; + uint64 v = Uint128Low64(seed) + result[1]; + return uint128(HashLen16(u, v + result[2]), + HashLen16(Rotate(v, 32), u * k0 + result[3])); + } +} + +uint128 CityHashCrc128(const char *s, size_t len) { + if (len <= 900) { + return CityHash128(s, len); + } else { + uint64 result[4]; + CityHashCrc256(s, len, result); + return uint128(result[2], result[3]); + } +} + +#endif -- cgit v1.2.3