mirror of
https://github.com/yuzu-mirror/yuzu
synced 2024-12-21 10:23:10 +00:00
f3805376f7
Allow sharing return types with the rest of the code base. For example, we use 'u128 = std::array<u64, 2>', meanwhile Google's code uses 'uint128 = std::pair<u64, u64>'. While we are at it, use size_t instead of std::size_t.
336 lines
11 KiB
C++
336 lines
11 KiB
C++
// 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 <algorithm>
|
|
#include <cstring>
|
|
#include <utility>
|
|
|
|
#include "common/cityhash.h"
|
|
#include "common/swap.h"
|
|
|
|
// #include "config.h"
|
|
#ifdef __GNUC__
|
|
#define HAVE_BUILTIN_EXPECT 1
|
|
#endif
|
|
#ifdef COMMON_BIG_ENDIAN
|
|
#define WORDS_BIGENDIAN 1
|
|
#endif
|
|
|
|
using namespace std;
|
|
|
|
namespace Common {
|
|
|
|
static u64 unaligned_load64(const char* p) {
|
|
u64 result;
|
|
std::memcpy(&result, p, sizeof(result));
|
|
return result;
|
|
}
|
|
|
|
static u32 unaligned_load32(const char* p) {
|
|
u32 result;
|
|
std::memcpy(&result, p, sizeof(result));
|
|
return result;
|
|
}
|
|
|
|
#ifdef WORDS_BIGENDIAN
|
|
#define uint32_in_expected_order(x) (swap32(x))
|
|
#define uint64_in_expected_order(x) (swap64(x))
|
|
#else
|
|
#define uint32_in_expected_order(x) (x)
|
|
#define uint64_in_expected_order(x) (x)
|
|
#endif
|
|
|
|
#if !defined(LIKELY)
|
|
#if HAVE_BUILTIN_EXPECT
|
|
#define LIKELY(x) (__builtin_expect(!!(x), 1))
|
|
#else
|
|
#define LIKELY(x) (x)
|
|
#endif
|
|
#endif
|
|
|
|
static u64 Fetch64(const char* p) {
|
|
return uint64_in_expected_order(unaligned_load64(p));
|
|
}
|
|
|
|
static u32 Fetch32(const char* p) {
|
|
return uint32_in_expected_order(unaligned_load32(p));
|
|
}
|
|
|
|
// Some primes between 2^63 and 2^64 for various uses.
|
|
static constexpr u64 k0 = 0xc3a5c85c97cb3127ULL;
|
|
static constexpr u64 k1 = 0xb492b66fbe98f273ULL;
|
|
static constexpr u64 k2 = 0x9ae16a3b2f90404fULL;
|
|
|
|
// Bitwise right rotate. Normally this will compile to a single
|
|
// instruction, especially if the shift is a manifest constant.
|
|
static u64 Rotate(u64 val, int shift) {
|
|
// Avoid shifting by 64: doing so yields an undefined result.
|
|
return shift == 0 ? val : ((val >> shift) | (val << (64 - shift)));
|
|
}
|
|
|
|
static u64 ShiftMix(u64 val) {
|
|
return val ^ (val >> 47);
|
|
}
|
|
|
|
static u64 HashLen16(u64 u, u64 v) {
|
|
return Hash128to64(u128{u, v});
|
|
}
|
|
|
|
static u64 HashLen16(u64 u, u64 v, u64 mul) {
|
|
// Murmur-inspired hashing.
|
|
u64 a = (u ^ v) * mul;
|
|
a ^= (a >> 47);
|
|
u64 b = (v ^ a) * mul;
|
|
b ^= (b >> 47);
|
|
b *= mul;
|
|
return b;
|
|
}
|
|
|
|
static u64 HashLen0to16(const char* s, size_t len) {
|
|
if (len >= 8) {
|
|
u64 mul = k2 + len * 2;
|
|
u64 a = Fetch64(s) + k2;
|
|
u64 b = Fetch64(s + len - 8);
|
|
u64 c = Rotate(b, 37) * mul + a;
|
|
u64 d = (Rotate(a, 25) + b) * mul;
|
|
return HashLen16(c, d, mul);
|
|
}
|
|
if (len >= 4) {
|
|
u64 mul = k2 + len * 2;
|
|
u64 a = Fetch32(s);
|
|
return HashLen16(len + (a << 3), Fetch32(s + len - 4), mul);
|
|
}
|
|
if (len > 0) {
|
|
u8 a = s[0];
|
|
u8 b = s[len >> 1];
|
|
u8 c = s[len - 1];
|
|
u32 y = static_cast<u32>(a) + (static_cast<u32>(b) << 8);
|
|
u32 z = static_cast<u32>(len) + (static_cast<u32>(c) << 2);
|
|
return ShiftMix(y * k2 ^ z * k0) * k2;
|
|
}
|
|
return k2;
|
|
}
|
|
|
|
// This probably works well for 16-byte strings as well, but it may be overkill
|
|
// in that case.
|
|
static u64 HashLen17to32(const char* s, size_t len) {
|
|
u64 mul = k2 + len * 2;
|
|
u64 a = Fetch64(s) * k1;
|
|
u64 b = Fetch64(s + 8);
|
|
u64 c = Fetch64(s + len - 8) * mul;
|
|
u64 d = Fetch64(s + len - 16) * k2;
|
|
return HashLen16(Rotate(a + b, 43) + Rotate(c, 30) + d, a + Rotate(b + k2, 18) + c, mul);
|
|
}
|
|
|
|
// 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<u64, u64> WeakHashLen32WithSeeds(u64 w, u64 x, u64 y, u64 z, u64 a, u64 b) {
|
|
a += w;
|
|
b = Rotate(b + a + z, 21);
|
|
u64 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<u64, u64> WeakHashLen32WithSeeds(const char* s, u64 a, u64 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 u64 HashLen33to64(const char* s, size_t len) {
|
|
u64 mul = k2 + len * 2;
|
|
u64 a = Fetch64(s) * k2;
|
|
u64 b = Fetch64(s + 8);
|
|
u64 c = Fetch64(s + len - 24);
|
|
u64 d = Fetch64(s + len - 32);
|
|
u64 e = Fetch64(s + 16) * k2;
|
|
u64 f = Fetch64(s + 24) * 9;
|
|
u64 g = Fetch64(s + len - 8);
|
|
u64 h = Fetch64(s + len - 16) * mul;
|
|
u64 u = Rotate(a + g, 43) + (Rotate(b, 30) + c) * 9;
|
|
u64 v = ((a + g) ^ d) + f + 1;
|
|
u64 w = swap64((u + v) * mul) + h;
|
|
u64 x = Rotate(e + f, 42) + c;
|
|
u64 y = (swap64((v + w) * mul) + g) * mul;
|
|
u64 z = e + f + c;
|
|
a = swap64((x + z) * mul + y) + b;
|
|
b = ShiftMix((z + a) * mul + d + h) * mul;
|
|
return b + x;
|
|
}
|
|
|
|
u64 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.
|
|
u64 x = Fetch64(s + len - 40);
|
|
u64 y = Fetch64(s + len - 16) + Fetch64(s + len - 56);
|
|
u64 z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24));
|
|
pair<u64, u64> v = WeakHashLen32WithSeeds(s + len - 64, len, z);
|
|
pair<u64, u64> 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<size_t>(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);
|
|
}
|
|
|
|
u64 CityHash64WithSeed(const char* s, size_t len, u64 seed) {
|
|
return CityHash64WithSeeds(s, len, k2, seed);
|
|
}
|
|
|
|
u64 CityHash64WithSeeds(const char* s, size_t len, u64 seed0, u64 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 u128 CityMurmur(const char* s, size_t len, u128 seed) {
|
|
u64 a = seed[0];
|
|
u64 b = seed[1];
|
|
u64 c = 0;
|
|
u64 d = 0;
|
|
signed long l = static_cast<long>(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 u128{a ^ b, HashLen16(b, a)};
|
|
}
|
|
|
|
u128 CityHash128WithSeed(const char* s, size_t len, u128 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<u64, u64> v, w;
|
|
u64 x = seed[0];
|
|
u64 y = seed[1];
|
|
u64 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;
|
|
y = y * k0 + Rotate(w.second, 37);
|
|
z = z * k0 + Rotate(w.first, 27);
|
|
w.first *= 9;
|
|
v.first *= 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);
|
|
v.first *= k0;
|
|
}
|
|
// 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 u128{HashLen16(x + v.second, w.second) + y, HashLen16(x + w.second, y + v.second)};
|
|
}
|
|
|
|
u128 CityHash128(const char* s, size_t len) {
|
|
return len >= 16 ? CityHash128WithSeed(s + 16, len - 16, u128{Fetch64(s), Fetch64(s + 8) + k0})
|
|
: CityHash128WithSeed(s, len, u128{k0, k1});
|
|
}
|
|
|
|
} // namespace Common
|