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common: Port cityhash code from Citra.
This commit is contained in:
bunnei
parent
da1114ca59
commit
45fd7c4a37
@ -32,6 +32,8 @@ add_library(common STATIC
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break_points.cpp
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break_points.h
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chunk_file.h
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cityhash.cpp
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cityhash.h
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code_block.h
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color.h
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common_funcs.h
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@ -39,7 +41,6 @@ add_library(common STATIC
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common_types.h
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file_util.cpp
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file_util.h
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hash.cpp
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hash.h
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linear_disk_cache.h
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logging/backend.cpp
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340
src/common/cityhash.cpp
Normal file
340
src/common/cityhash.cpp
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@ -0,0 +1,340 @@
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// Copyright (c) 2011 Google, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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// CityHash, by Geoff Pike and Jyrki Alakuijala
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//
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// This file provides CityHash64() and related functions.
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//
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// It's probably possible to create even faster hash functions by
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// writing a program that systematically explores some of the space of
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// possible hash functions, by using SIMD instructions, or by
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// compromising on hash quality.
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#include <algorithm>
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#include <string.h> // for memcpy and memset
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#include "cityhash.h"
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#include "common/swap.h"
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// #include "config.h"
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#ifdef __GNUC__
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#define HAVE_BUILTIN_EXPECT 1
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#endif
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#ifdef COMMON_BIG_ENDIAN
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#define WORDS_BIGENDIAN 1
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#endif
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using namespace std;
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typedef uint8_t uint8;
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typedef uint32_t uint32;
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typedef uint64_t uint64;
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namespace Common {
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static uint64 UNALIGNED_LOAD64(const char* p) {
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uint64 result;
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memcpy(&result, p, sizeof(result));
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return result;
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}
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static uint32 UNALIGNED_LOAD32(const char* p) {
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uint32 result;
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memcpy(&result, p, sizeof(result));
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return result;
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}
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#ifdef WORDS_BIGENDIAN
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#define uint32_in_expected_order(x) (swap32(x))
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#define uint64_in_expected_order(x) (swap64(x))
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#else
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#define uint32_in_expected_order(x) (x)
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#define uint64_in_expected_order(x) (x)
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#endif
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#if !defined(LIKELY)
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#if HAVE_BUILTIN_EXPECT
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#define LIKELY(x) (__builtin_expect(!!(x), 1))
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#else
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#define LIKELY(x) (x)
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#endif
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#endif
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static uint64 Fetch64(const char* p) {
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return uint64_in_expected_order(UNALIGNED_LOAD64(p));
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}
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static uint32 Fetch32(const char* p) {
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return uint32_in_expected_order(UNALIGNED_LOAD32(p));
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}
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// Some primes between 2^63 and 2^64 for various uses.
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static const uint64 k0 = 0xc3a5c85c97cb3127ULL;
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static const uint64 k1 = 0xb492b66fbe98f273ULL;
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static const uint64 k2 = 0x9ae16a3b2f90404fULL;
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// Bitwise right rotate. Normally this will compile to a single
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// instruction, especially if the shift is a manifest constant.
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static uint64 Rotate(uint64 val, int shift) {
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// Avoid shifting by 64: doing so yields an undefined result.
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return shift == 0 ? val : ((val >> shift) | (val << (64 - shift)));
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}
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static uint64 ShiftMix(uint64 val) {
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return val ^ (val >> 47);
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}
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static uint64 HashLen16(uint64 u, uint64 v) {
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return Hash128to64(uint128(u, v));
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}
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static uint64 HashLen16(uint64 u, uint64 v, uint64 mul) {
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// Murmur-inspired hashing.
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uint64 a = (u ^ v) * mul;
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a ^= (a >> 47);
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uint64 b = (v ^ a) * mul;
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b ^= (b >> 47);
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b *= mul;
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return b;
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}
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static uint64 HashLen0to16(const char* s, size_t len) {
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if (len >= 8) {
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uint64 mul = k2 + len * 2;
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uint64 a = Fetch64(s) + k2;
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uint64 b = Fetch64(s + len - 8);
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uint64 c = Rotate(b, 37) * mul + a;
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uint64 d = (Rotate(a, 25) + b) * mul;
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return HashLen16(c, d, mul);
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}
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if (len >= 4) {
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uint64 mul = k2 + len * 2;
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uint64 a = Fetch32(s);
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return HashLen16(len + (a << 3), Fetch32(s + len - 4), mul);
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}
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if (len > 0) {
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uint8 a = s[0];
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uint8 b = s[len >> 1];
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uint8 c = s[len - 1];
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uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
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uint32 z = static_cast<uint32>(len) + (static_cast<uint32>(c) << 2);
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return ShiftMix(y * k2 ^ z * k0) * k2;
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}
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return k2;
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}
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// This probably works well for 16-byte strings as well, but it may be overkill
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// in that case.
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static uint64 HashLen17to32(const char* s, size_t len) {
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uint64 mul = k2 + len * 2;
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uint64 a = Fetch64(s) * k1;
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uint64 b = Fetch64(s + 8);
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uint64 c = Fetch64(s + len - 8) * mul;
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uint64 d = Fetch64(s + len - 16) * k2;
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return HashLen16(Rotate(a + b, 43) + Rotate(c, 30) + d, a + Rotate(b + k2, 18) + c, mul);
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}
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// Return a 16-byte hash for 48 bytes. Quick and dirty.
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// Callers do best to use "random-looking" values for a and b.
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static pair<uint64, uint64> WeakHashLen32WithSeeds(uint64 w, uint64 x, uint64 y, uint64 z, uint64 a,
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uint64 b) {
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a += w;
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b = Rotate(b + a + z, 21);
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uint64 c = a;
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a += x;
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a += y;
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b += Rotate(a, 44);
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return make_pair(a + z, b + c);
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}
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// Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.
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static pair<uint64, uint64> WeakHashLen32WithSeeds(const char* s, uint64 a, uint64 b) {
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return WeakHashLen32WithSeeds(Fetch64(s), Fetch64(s + 8), Fetch64(s + 16), Fetch64(s + 24), a,
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b);
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}
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// Return an 8-byte hash for 33 to 64 bytes.
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static uint64 HashLen33to64(const char* s, size_t len) {
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uint64 mul = k2 + len * 2;
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uint64 a = Fetch64(s) * k2;
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uint64 b = Fetch64(s + 8);
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uint64 c = Fetch64(s + len - 24);
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uint64 d = Fetch64(s + len - 32);
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uint64 e = Fetch64(s + 16) * k2;
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uint64 f = Fetch64(s + 24) * 9;
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uint64 g = Fetch64(s + len - 8);
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uint64 h = Fetch64(s + len - 16) * mul;
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uint64 u = Rotate(a + g, 43) + (Rotate(b, 30) + c) * 9;
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uint64 v = ((a + g) ^ d) + f + 1;
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uint64 w = swap64((u + v) * mul) + h;
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uint64 x = Rotate(e + f, 42) + c;
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uint64 y = (swap64((v + w) * mul) + g) * mul;
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uint64 z = e + f + c;
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a = swap64((x + z) * mul + y) + b;
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b = ShiftMix((z + a) * mul + d + h) * mul;
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return b + x;
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}
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uint64 CityHash64(const char* s, size_t len) {
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if (len <= 32) {
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if (len <= 16) {
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return HashLen0to16(s, len);
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} else {
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return HashLen17to32(s, len);
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}
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} else if (len <= 64) {
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return HashLen33to64(s, len);
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}
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// For strings over 64 bytes we hash the end first, and then as we
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// loop we keep 56 bytes of state: v, w, x, y, and z.
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uint64 x = Fetch64(s + len - 40);
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uint64 y = Fetch64(s + len - 16) + Fetch64(s + len - 56);
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uint64 z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24));
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pair<uint64, uint64> v = WeakHashLen32WithSeeds(s + len - 64, len, z);
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pair<uint64, uint64> w = WeakHashLen32WithSeeds(s + len - 32, y + k1, x);
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x = x * k1 + Fetch64(s);
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// Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
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len = (len - 1) & ~static_cast<size_t>(63);
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do {
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x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
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y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
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x ^= w.second;
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y += v.first + Fetch64(s + 40);
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z = Rotate(z + w.first, 33) * k1;
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v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
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w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
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std::swap(z, x);
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s += 64;
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len -= 64;
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} while (len != 0);
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return HashLen16(HashLen16(v.first, w.first) + ShiftMix(y) * k1 + z,
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HashLen16(v.second, w.second) + x);
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}
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uint64 CityHash64WithSeed(const char* s, size_t len, uint64 seed) {
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return CityHash64WithSeeds(s, len, k2, seed);
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}
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uint64 CityHash64WithSeeds(const char* s, size_t len, uint64 seed0, uint64 seed1) {
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return HashLen16(CityHash64(s, len) - seed0, seed1);
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}
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// A subroutine for CityHash128(). Returns a decent 128-bit hash for strings
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// of any length representable in signed long. Based on City and Murmur.
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static uint128 CityMurmur(const char* s, size_t len, uint128 seed) {
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uint64 a = Uint128Low64(seed);
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uint64 b = Uint128High64(seed);
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uint64 c = 0;
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uint64 d = 0;
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signed long l = static_cast<long>(len) - 16;
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if (l <= 0) { // len <= 16
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a = ShiftMix(a * k1) * k1;
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c = b * k1 + HashLen0to16(s, len);
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d = ShiftMix(a + (len >= 8 ? Fetch64(s) : c));
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} else { // len > 16
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c = HashLen16(Fetch64(s + len - 8) + k1, a);
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d = HashLen16(b + len, c + Fetch64(s + len - 16));
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a += d;
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do {
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a ^= ShiftMix(Fetch64(s) * k1) * k1;
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a *= k1;
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b ^= a;
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c ^= ShiftMix(Fetch64(s + 8) * k1) * k1;
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c *= k1;
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d ^= c;
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s += 16;
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l -= 16;
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} while (l > 0);
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}
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a = HashLen16(a, c);
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b = HashLen16(d, b);
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return uint128(a ^ b, HashLen16(b, a));
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}
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uint128 CityHash128WithSeed(const char* s, size_t len, uint128 seed) {
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if (len < 128) {
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return CityMurmur(s, len, seed);
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}
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// We expect len >= 128 to be the common case. Keep 56 bytes of state:
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// v, w, x, y, and z.
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pair<uint64, uint64> v, w;
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uint64 x = Uint128Low64(seed);
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uint64 y = Uint128High64(seed);
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uint64 z = len * k1;
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v.first = Rotate(y ^ k1, 49) * k1 + Fetch64(s);
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v.second = Rotate(v.first, 42) * k1 + Fetch64(s + 8);
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w.first = Rotate(y + z, 35) * k1 + x;
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w.second = Rotate(x + Fetch64(s + 88), 53) * k1;
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// This is the same inner loop as CityHash64(), manually unrolled.
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do {
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x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
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y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
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x ^= w.second;
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y += v.first + Fetch64(s + 40);
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z = Rotate(z + w.first, 33) * k1;
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v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
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w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
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std::swap(z, x);
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s += 64;
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x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
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y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
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x ^= w.second;
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y += v.first + Fetch64(s + 40);
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z = Rotate(z + w.first, 33) * k1;
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v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
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w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
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std::swap(z, x);
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s += 64;
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len -= 128;
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} while (LIKELY(len >= 128));
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x += Rotate(v.first + z, 49) * k0;
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y = y * k0 + Rotate(w.second, 37);
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z = z * k0 + Rotate(w.first, 27);
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w.first *= 9;
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v.first *= k0;
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// If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s.
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for (size_t tail_done = 0; tail_done < len;) {
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tail_done += 32;
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y = Rotate(x + y, 42) * k0 + v.second;
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w.first += Fetch64(s + len - tail_done + 16);
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x = x * k0 + w.first;
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z += w.second + Fetch64(s + len - tail_done);
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w.second += v.first;
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v = WeakHashLen32WithSeeds(s + len - tail_done, v.first + z, v.second);
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v.first *= k0;
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}
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// At this point our 56 bytes of state should contain more than
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// enough information for a strong 128-bit hash. We use two
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// different 56-byte-to-8-byte hashes to get a 16-byte final result.
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x = HashLen16(x, v.first);
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y = HashLen16(y + z, w.first);
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return uint128(HashLen16(x + v.second, w.second) + y, HashLen16(x + w.second, y + v.second));
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}
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uint128 CityHash128(const char* s, size_t len) {
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return len >= 16
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? CityHash128WithSeed(s + 16, len - 16, uint128(Fetch64(s), Fetch64(s + 8) + k0))
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: CityHash128WithSeed(s, len, uint128(k0, k1));
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}
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} // namespace Common
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110
src/common/cityhash.h
Normal file
110
src/common/cityhash.h
Normal file
@ -0,0 +1,110 @@
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// Copyright (c) 2011 Google, Inc.
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||||
//
|
||||
// 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
|
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//
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// http://code.google.com/p/cityhash/
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//
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// This file provides a few functions for hashing strings. All of them are
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// high-quality functions in the sense that they pass standard tests such
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// as Austin Appleby's SMHasher. They are also fast.
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//
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// For 64-bit x86 code, on short strings, we don't know of anything faster than
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// CityHash64 that is of comparable quality. We believe our nearest competitor
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// is Murmur3. For 64-bit x86 code, CityHash64 is an excellent choice for hash
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// tables and most other hashing (excluding cryptography).
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//
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// For 64-bit x86 code, on long strings, the picture is more complicated.
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// On many recent Intel CPUs, such as Nehalem, Westmere, Sandy Bridge, etc.,
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// CityHashCrc128 appears to be faster than all competitors of comparable
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// quality. CityHash128 is also good but not quite as fast. We believe our
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// nearest competitor is Bob Jenkins' Spooky. We don't have great data for
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||||
// other 64-bit CPUs, but for long strings we know that Spooky is slightly
|
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// faster than CityHash on some relatively recent AMD x86-64 CPUs, for example.
|
||||
// Note that CityHashCrc128 is declared in citycrc.h.
|
||||
//
|
||||
// For 32-bit x86 code, we don't know of anything faster than CityHash32 that
|
||||
// is of comparable quality. We believe our nearest competitor is Murmur3A.
|
||||
// (On 64-bit CPUs, it is typically faster to use the other CityHash variants.)
|
||||
//
|
||||
// Functions in the CityHash family are not suitable for cryptography.
|
||||
//
|
||||
// Please see CityHash's README file for more details on our performance
|
||||
// measurements and so on.
|
||||
//
|
||||
// WARNING: This code has been only lightly tested on big-endian platforms!
|
||||
// It is known to work well on little-endian platforms that have a small penalty
|
||||
// for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs.
|
||||
// It should work on all 32-bit and 64-bit platforms that allow unaligned reads;
|
||||
// bug reports are welcome.
|
||||
//
|
||||
// By the way, for some hash functions, given strings a and b, the hash
|
||||
// of a+b is easily derived from the hashes of a and b. This property
|
||||
// doesn't hold for any hash functions in this file.
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <utility>
|
||||
#include <stdint.h>
|
||||
#include <stdlib.h> // for size_t.
|
||||
|
||||
namespace Common {
|
||||
|
||||
typedef std::pair<uint64_t, uint64_t> uint128;
|
||||
|
||||
inline uint64_t Uint128Low64(const uint128& x) {
|
||||
return x.first;
|
||||
}
|
||||
inline uint64_t Uint128High64(const uint128& x) {
|
||||
return x.second;
|
||||
}
|
||||
|
||||
// Hash function for a byte array.
|
||||
uint64_t CityHash64(const char* buf, size_t len);
|
||||
|
||||
// Hash function for a byte array. For convenience, a 64-bit seed is also
|
||||
// hashed into the result.
|
||||
uint64_t CityHash64WithSeed(const char* buf, size_t len, uint64_t seed);
|
||||
|
||||
// Hash function for a byte array. For convenience, two seeds are also
|
||||
// hashed into the result.
|
||||
uint64_t CityHash64WithSeeds(const char* buf, size_t len, uint64_t seed0, uint64_t seed1);
|
||||
|
||||
// Hash function for a byte array.
|
||||
uint128 CityHash128(const char* s, size_t len);
|
||||
|
||||
// Hash function for a byte array. For convenience, a 128-bit seed is also
|
||||
// hashed into the result.
|
||||
uint128 CityHash128WithSeed(const char* s, size_t len, uint128 seed);
|
||||
|
||||
// Hash 128 input bits down to 64 bits of output.
|
||||
// This is intended to be a reasonably good hash function.
|
||||
inline uint64_t Hash128to64(const uint128& x) {
|
||||
// Murmur-inspired hashing.
|
||||
const uint64_t kMul = 0x9ddfea08eb382d69ULL;
|
||||
uint64_t a = (Uint128Low64(x) ^ Uint128High64(x)) * kMul;
|
||||
a ^= (a >> 47);
|
||||
uint64_t b = (Uint128High64(x) ^ a) * kMul;
|
||||
b ^= (b >> 47);
|
||||
b *= kMul;
|
||||
return b;
|
||||
}
|
||||
|
||||
} // namespace Common
|
||||
@ -1,141 +0,0 @@
|
||||
// Copyright 2015 Citra Emulator Project
|
||||
// Licensed under GPLv2 or any later version
|
||||
// Refer to the license.txt file included.
|
||||
|
||||
#if defined(_MSC_VER)
|
||||
#include <stdlib.h>
|
||||
#endif
|
||||
#include "common/common_funcs.h"
|
||||
#include "common/common_types.h"
|
||||
#include "common/hash.h"
|
||||
|
||||
namespace Common {
|
||||
|
||||
// MurmurHash3 was written by Austin Appleby, and is placed in the public
|
||||
// domain. The author hereby disclaims copyright to this source code.
|
||||
|
||||
// Block read - if your platform needs to do endian-swapping or can only handle aligned reads, do
|
||||
// the conversion here
|
||||
static FORCE_INLINE u64 getblock64(const u64* p, size_t i) {
|
||||
return p[i];
|
||||
}
|
||||
|
||||
// Finalization mix - force all bits of a hash block to avalanche
|
||||
static FORCE_INLINE u64 fmix64(u64 k) {
|
||||
k ^= k >> 33;
|
||||
k *= 0xff51afd7ed558ccdllu;
|
||||
k ^= k >> 33;
|
||||
k *= 0xc4ceb9fe1a85ec53llu;
|
||||
k ^= k >> 33;
|
||||
|
||||
return k;
|
||||
}
|
||||
|
||||
// This is the 128-bit variant of the MurmurHash3 hash function that is targeted for 64-bit
|
||||
// platforms (MurmurHash3_x64_128). It was taken from:
|
||||
// https://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
|
||||
void MurmurHash3_128(const void* key, size_t len, u32 seed, void* out) {
|
||||
const u8* data = (const u8*)key;
|
||||
const size_t nblocks = len / 16;
|
||||
|
||||
u64 h1 = seed;
|
||||
u64 h2 = seed;
|
||||
|
||||
const u64 c1 = 0x87c37b91114253d5llu;
|
||||
const u64 c2 = 0x4cf5ad432745937fllu;
|
||||
|
||||
// Body
|
||||
|
||||
const u64* blocks = (const u64*)(data);
|
||||
|
||||
for (size_t i = 0; i < nblocks; i++) {
|
||||
u64 k1 = getblock64(blocks, i * 2 + 0);
|
||||
u64 k2 = getblock64(blocks, i * 2 + 1);
|
||||
|
||||
k1 *= c1;
|
||||
k1 = _rotl64(k1, 31);
|
||||
k1 *= c2;
|
||||
h1 ^= k1;
|
||||
|
||||
h1 = _rotl64(h1, 27);
|
||||
h1 += h2;
|
||||
h1 = h1 * 5 + 0x52dce729;
|
||||
|
||||
k2 *= c2;
|
||||
k2 = _rotl64(k2, 33);
|
||||
k2 *= c1;
|
||||
h2 ^= k2;
|
||||
|
||||
h2 = _rotl64(h2, 31);
|
||||
h2 += h1;
|
||||
h2 = h2 * 5 + 0x38495ab5;
|
||||
}
|
||||
|
||||
// Tail
|
||||
|
||||
const u8* tail = (const u8*)(data + nblocks * 16);
|
||||
|
||||
u64 k1 = 0;
|
||||
u64 k2 = 0;
|
||||
|
||||
switch (len & 15) {
|
||||
case 15:
|
||||
k2 ^= ((u64)tail[14]) << 48;
|
||||
case 14:
|
||||
k2 ^= ((u64)tail[13]) << 40;
|
||||
case 13:
|
||||
k2 ^= ((u64)tail[12]) << 32;
|
||||
case 12:
|
||||
k2 ^= ((u64)tail[11]) << 24;
|
||||
case 11:
|
||||
k2 ^= ((u64)tail[10]) << 16;
|
||||
case 10:
|
||||
k2 ^= ((u64)tail[9]) << 8;
|
||||
case 9:
|
||||
k2 ^= ((u64)tail[8]) << 0;
|
||||
k2 *= c2;
|
||||
k2 = _rotl64(k2, 33);
|
||||
k2 *= c1;
|
||||
h2 ^= k2;
|
||||
|
||||
case 8:
|
||||
k1 ^= ((u64)tail[7]) << 56;
|
||||
case 7:
|
||||
k1 ^= ((u64)tail[6]) << 48;
|
||||
case 6:
|
||||
k1 ^= ((u64)tail[5]) << 40;
|
||||
case 5:
|
||||
k1 ^= ((u64)tail[4]) << 32;
|
||||
case 4:
|
||||
k1 ^= ((u64)tail[3]) << 24;
|
||||
case 3:
|
||||
k1 ^= ((u64)tail[2]) << 16;
|
||||
case 2:
|
||||
k1 ^= ((u64)tail[1]) << 8;
|
||||
case 1:
|
||||
k1 ^= ((u64)tail[0]) << 0;
|
||||
k1 *= c1;
|
||||
k1 = _rotl64(k1, 31);
|
||||
k1 *= c2;
|
||||
h1 ^= k1;
|
||||
};
|
||||
|
||||
// Finalization
|
||||
|
||||
h1 ^= len;
|
||||
h2 ^= len;
|
||||
|
||||
h1 += h2;
|
||||
h2 += h1;
|
||||
|
||||
h1 = fmix64(h1);
|
||||
h2 = fmix64(h2);
|
||||
|
||||
h1 += h2;
|
||||
h2 += h1;
|
||||
|
||||
((u64*)out)[0] = h1;
|
||||
((u64*)out)[1] = h2;
|
||||
}
|
||||
|
||||
} // namespace Common
|
||||
@ -5,12 +5,12 @@
|
||||
#pragma once
|
||||
|
||||
#include <cstddef>
|
||||
#include <cstring>
|
||||
#include "common/cityhash.h"
|
||||
#include "common/common_types.h"
|
||||
|
||||
namespace Common {
|
||||
|
||||
void MurmurHash3_128(const void* key, size_t len, u32 seed, void* out);
|
||||
|
||||
/**
|
||||
* Computes a 64-bit hash over the specified block of data
|
||||
* @param data Block of data to compute hash over
|
||||
@ -18,9 +18,54 @@ void MurmurHash3_128(const void* key, size_t len, u32 seed, void* out);
|
||||
* @returns 64-bit hash value that was computed over the data block
|
||||
*/
|
||||
static inline u64 ComputeHash64(const void* data, size_t len) {
|
||||
u64 res[2];
|
||||
MurmurHash3_128(data, len, 0, res);
|
||||
return res[0];
|
||||
return CityHash64(static_cast<const char*>(data), len);
|
||||
}
|
||||
|
||||
/**
|
||||
* Computes a 64-bit hash of a struct. In addition to being trivially copyable, it is also critical
|
||||
* that either the struct includes no padding, or that any padding is initialized to a known value
|
||||
* by memsetting the struct to 0 before filling it in.
|
||||
*/
|
||||
template <typename T>
|
||||
static inline u64 ComputeStructHash64(const T& data) {
|
||||
static_assert(std::is_trivially_copyable<T>(),
|
||||
"Type passed to ComputeStructHash64 must be trivially copyable");
|
||||
return ComputeHash64(&data, sizeof(data));
|
||||
}
|
||||
|
||||
/// A helper template that ensures the padding in a struct is initialized by memsetting to 0.
|
||||
template <typename T>
|
||||
struct HashableStruct {
|
||||
// In addition to being trivially copyable, T must also have a trivial default constructor,
|
||||
// because any member initialization would be overridden by memset
|
||||
static_assert(std::is_trivial<T>(), "Type passed to HashableStruct must be trivial");
|
||||
/*
|
||||
* We use a union because "implicitly-defined copy/move constructor for a union X copies the
|
||||
* object representation of X." and "implicitly-defined copy assignment operator for a union X
|
||||
* copies the object representation (3.9) of X." = Bytewise copy instead of memberwise copy.
|
||||
* This is important because the padding bytes are included in the hash and comparison between
|
||||
* objects.
|
||||
*/
|
||||
union {
|
||||
T state;
|
||||
};
|
||||
|
||||
HashableStruct() {
|
||||
// Memset structure to zero padding bits, so that they will be deterministic when hashing
|
||||
std::memset(&state, 0, sizeof(T));
|
||||
}
|
||||
|
||||
bool operator==(const HashableStruct<T>& o) const {
|
||||
return std::memcmp(&state, &o.state, sizeof(T)) == 0;
|
||||
};
|
||||
|
||||
bool operator!=(const HashableStruct<T>& o) const {
|
||||
return !(*this == o);
|
||||
};
|
||||
|
||||
size_t Hash() const {
|
||||
return Common::ComputeStructHash64(state);
|
||||
}
|
||||
};
|
||||
|
||||
} // namespace Common
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user