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/*
* Copyright (C) 2018-2022 Intel Corporation
*
* SPDX-License-Identifier: MIT
*
*/
#pragma once
#include <cstddef>
#include <cstdint>
namespace NEO {
// clang-format off
#define HASH_JENKINS_MIX(a,b,c) \
{ \
a -= b; a -= c; a ^= (c>>13); \
b -= c; b -= a; b ^= (a<<8); \
c -= a; c -= b; c ^= (b>>13); \
a -= b; a -= c; a ^= (c>>12); \
b -= c; b -= a; b ^= (a<<16); \
c -= a; c -= b; c ^= (b>>5); \
a -= b; a -= c; a ^= (c>>3); \
b -= c; b -= a; b ^= (a<<10); \
c -= a; c -= b; c ^= (b>>15); \
}
// clang-format on
class Hash {
public:
Hash() {
reset();
};
uint32_t getValue(const char *data, size_t size) {
uint32_t value = 0;
switch (size) {
case 3:
value = static_cast<uint32_t>(*reinterpret_cast<const unsigned char *>(data++));
value <<= 8;
[[fallthrough]];
case 2:
value |= static_cast<uint32_t>(*reinterpret_cast<const unsigned char *>(data++));
value <<= 8;
[[fallthrough]];
case 1:
value |= static_cast<uint32_t>(*reinterpret_cast<const unsigned char *>(data++));
value <<= 8;
}
return value;
}
void update(const char *buff, size_t size) {
if (buff == nullptr)
return;
if ((reinterpret_cast<uintptr_t>(buff) & 0x3) != 0) {
const unsigned char *tmp = (const unsigned char *)buff;
while (size >= sizeof(uint32_t)) {
uint32_t value = (uint32_t)tmp[0] + (((uint32_t)tmp[1]) << 8) + ((uint32_t)tmp[2] << 16) + ((uint32_t)tmp[3] << 24);
a ^= value;
HASH_JENKINS_MIX(a, hi, lo);
size -= sizeof(uint32_t);
tmp += sizeof(uint32_t);
}
if (size > 0) {
uint32_t value = getValue((char *)tmp, size);
a ^= value;
HASH_JENKINS_MIX(a, hi, lo);
}
} else {
const uint32_t *tmp = reinterpret_cast<const uint32_t *>(buff);
while (size >= sizeof(*tmp)) {
a ^= *(tmp++);
HASH_JENKINS_MIX(a, hi, lo);
size -= sizeof(*tmp);
}
if (size > 0) {
uint32_t value = getValue((char *)tmp, size);
a ^= value;
HASH_JENKINS_MIX(a, hi, lo);
}
}
}
uint64_t finish() {
return (((uint64_t)hi) << 32) | lo;
}
void reset() {
a = 0x428a2f98;
hi = 0x71374491;
lo = 0xb5c0fbcf;
}
static uint64_t hash(const char *buff, size_t size) {
Hash hash;
hash.update(buff, size);
return hash.finish();
}
protected:
uint32_t a, hi, lo;
};
template <typename T>
uint32_t hashPtrToU32(const T *src) {
auto asInt = reinterpret_cast<uintptr_t>(src);
constexpr auto m = sizeof(uintptr_t) / 8;
asInt = asInt ^ ((asInt & ~(m - 1)) >> (m * 32));
return static_cast<uint32_t>(asInt);
}
} // namespace NEO
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