mirror of
https://github.com/Lime3DS/Lime3DS
synced 2024-11-16 04:03:43 +00:00
141 lines
3.1 KiB
C++
141 lines
3.1 KiB
C++
// 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
|