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Diffstat (limited to '')
-rwxr-xr-x | other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp b/other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp new file mode 100755 index 0000000000..f34777eb84 --- /dev/null +++ b/other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp @@ -0,0 +1,322 @@ +// 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 Version 1, 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 "city.h" + +#include <algorithm> + +using namespace std; + +#if __sparc__ +#include <string.h> +static inline uint64 UNALIGNED_LOAD64(const char *p) { + uint64 val; + memcpy(&val, p, sizeof(uint64)); + return val; +} + +static inline uint32 UNALIGNED_LOAD32(const char *p) { + uint32 val; + memcpy(&val, p, sizeof(uint32)); + return val; +} +#else +#define UNALIGNED_LOAD64(p) (*(const uint64*)(p)) +#define UNALIGNED_LOAD32(p) (*(const uint32*)(p)) +#endif + +#if !defined(LIKELY) +#if defined(__GNUC__) +#define LIKELY(x) (__builtin_expect(!!(x), 1)) +#else +#define LIKELY(x) (x) +#endif +#endif + +// Some primes between 2^63 and 2^64 for various uses. +static const uint64 k0 = 0xc3a5c85c97cb3127; +static const uint64 k1 = 0xb492b66fbe98f273; +static const uint64 k2 = 0x9ae16a3b2f90404f; +static const uint64 k3 = 0xc949d7c7509e6557; + +// 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 = UNALIGNED_LOAD64(s); + uint64 b = UNALIGNED_LOAD64(s + len - 8); + return HashLen16(a, RotateByAtLeast1(b + len, len)) ^ b; + } + if (len >= 4) { + uint64 a = UNALIGNED_LOAD32(s); + return HashLen16(len + (a << 3), UNALIGNED_LOAD32(s + len - 4)); + } + if (len > 0) { + uint8 a = s[0]; + uint8 b = s[len >> 1]; + uint8 c = s[len - 1]; + uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8); + uint32 z = len + (static_cast<uint32>(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 = UNALIGNED_LOAD64(s) * k1; + uint64 b = UNALIGNED_LOAD64(s + 8); + uint64 c = UNALIGNED_LOAD64(s + len - 8) * k2; + uint64 d = UNALIGNED_LOAD64(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<uint64, uint64> 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<uint64, uint64> WeakHashLen32WithSeeds( + const char* s, uint64 a, uint64 b) { + return WeakHashLen32WithSeeds(UNALIGNED_LOAD64(s), + UNALIGNED_LOAD64(s + 8), + UNALIGNED_LOAD64(s + 16), + UNALIGNED_LOAD64(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 = UNALIGNED_LOAD64(s + 24); + uint64 a = UNALIGNED_LOAD64(s) + (len + UNALIGNED_LOAD64(s + len - 16)) * k0; + uint64 b = Rotate(a + z, 52); + uint64 c = Rotate(a, 37); + a += UNALIGNED_LOAD64(s + 8); + c += Rotate(a, 7); + a += UNALIGNED_LOAD64(s + 16); + uint64 vf = a + z; + uint64 vs = b + Rotate(a, 31) + c; + a = UNALIGNED_LOAD64(s + 16) + UNALIGNED_LOAD64(s + len - 32); + z = UNALIGNED_LOAD64(s + len - 8); + b = Rotate(a + z, 52); + c = Rotate(a, 37); + a += UNALIGNED_LOAD64(s + len - 24); + c += Rotate(a, 7); + a += UNALIGNED_LOAD64(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 = UNALIGNED_LOAD64(s); + uint64 y = UNALIGNED_LOAD64(s + len - 16) ^ k1; + uint64 z = UNALIGNED_LOAD64(s + len - 56) ^ k0; + pair<uint64, uint64> v = WeakHashLen32WithSeeds(s + len - 64, len, y); + pair<uint64, uint64> w = WeakHashLen32WithSeeds(s + len - 32, len * k1, k0); + z += ShiftMix(v.second) * k1; + x = Rotate(z + x, 39) * k1; + y = Rotate(y, 33) * k1; + + // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks. + len = (len - 1) & ~static_cast<size_t>(63); + do { + x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1; + y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1; + x ^= w.second; + y ^= v.first; + z = Rotate(z ^ w.first, 33); + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y); + 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 an int. 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; + int l = len - 16; + if (l <= 0) { // len <= 16 + c = b * k1 + HashLen0to16(s, len); + d = Rotate(a + (len >= 8 ? UNALIGNED_LOAD64(s) : c), 32); + } else { // len > 16 + c = HashLen16(UNALIGNED_LOAD64(s + len - 8) + k1, a); + d = HashLen16(b + len, c + UNALIGNED_LOAD64(s + len - 16)); + a += d; + do { + a ^= ShiftMix(UNALIGNED_LOAD64(s) * k1) * k1; + a *= k1; + b ^= a; + c ^= ShiftMix(UNALIGNED_LOAD64(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<uint64, uint64> v, w; + uint64 x = Uint128Low64(seed); + uint64 y = Uint128High64(seed); + uint64 z = len * k1; + v.first = Rotate(y ^ k1, 49) * k1 + UNALIGNED_LOAD64(s); + v.second = Rotate(v.first, 42) * k1 + UNALIGNED_LOAD64(s + 8); + w.first = Rotate(y + z, 35) * k1 + x; + w.second = Rotate(x + UNALIGNED_LOAD64(s + 88), 53) * k1; + + // This is the same inner loop as CityHash64(), manually unrolled. + do { + x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1; + y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1; + x ^= w.second; + y ^= v.first; + z = Rotate(z ^ w.first, 33); + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y); + std::swap(z, x); + s += 64; + x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1; + y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1; + x ^= w.second; + y ^= v.first; + z = Rotate(z ^ w.first, 33); + v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first); + w = WeakHashLen32WithSeeds(s + 32, z + w.second, y); + std::swap(z, x); + s += 64; + len -= 128; + } while (LIKELY(len >= 128)); + y += Rotate(w.first, 37) * k0 + z; + x += Rotate(v.first + z, 49) * 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(y - x, 42) * k0 + v.second; + w.first += UNALIGNED_LOAD64(s + len - tail_done + 16); + x = Rotate(x, 49) * k0 + w.first; + w.first += v.first; + v = WeakHashLen32WithSeeds(s + len - tail_done, v.first, v.second); + } + // At this point our 48 bytes of state should contain more than + // enough information for a strong 128-bit hash. We use two + // different 48-byte-to-8-byte hashes to get a 16-byte final result. + x = HashLen16(x, v.first); + y = HashLen16(y, 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(UNALIGNED_LOAD64(s) ^ k3, + UNALIGNED_LOAD64(s + 8))); + } else if (len >= 8) { + return CityHash128WithSeed(NULL, + 0, + uint128(UNALIGNED_LOAD64(s) ^ (len * k0), + UNALIGNED_LOAD64(s + len - 8) ^ k1)); + } else { + return CityHash128WithSeed(s, len, uint128(k0, k1)); + } +} |