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#include "hash-impl.hpp"
#include <bit>
#ifdef __GNUG__
#pragma GCC diagnostic ignored "-Wcast-align"
#pragma GCC diagnostic ignored "-Wsign-conversion"
#endif
// ReSharper disable CppDefaultCaseNotHandledInSwitchStatement
// NOLINTBEGIN(*-switch-missing-default-case, *-multiway-paths-covered)
namespace floormat::SipHash {
namespace {
/* default: SipHash-2-4 */
constexpr inline int cROUNDS = 2, dROUNDS = 4;
CORRADE_ALWAYS_INLINE void U32TO8_LE(uint8_t* __restrict p, uint32_t v)
{
(p)[0] = (uint8_t)((v));
(p)[1] = (uint8_t)((v) >> 8);
(p)[2] = (uint8_t)((v) >> 16);
(p)[3] = (uint8_t)((v) >> 24);
}
CORRADE_ALWAYS_INLINE void U64TO8_LE(uint8_t* __restrict p, uint64_t v)
{
U32TO8_LE((p), (uint32_t)((v)));
U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
}
constexpr CORRADE_ALWAYS_INLINE uint64_t U8TO64_LE(const uint8_t* __restrict p)
{
return (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) |
((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) |
((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) |
((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56));
}
#define SIPROUND \
do { \
v0 += v1; \
v1 = std::rotl(v1, 13); \
v1 ^= v0; \
v0 = std::rotl(v0, 32); \
v2 += v3; \
v3 = std::rotl(v3, 16); \
v3 ^= v2; \
v0 += v3; \
v3 = std::rotl(v3, 21); \
v3 ^= v0; \
v2 += v1; \
v1 = std::rotl(v1, 17); \
v1 ^= v2; \
v2 = std::rotl(v2, 32); \
} while (0)
struct Key { uint64_t k0, k1; };
constexpr Key make_key()
{
uint8_t buf[16];
for (uint8_t i = 0; i < 16; i++)
buf[i] = i;
return { U8TO64_LE(buf), U8TO64_LE(buf+8) };
}
/*
Computes a SipHash value
*in: pointer to input data (read-only)
inlen: input data length in bytes (any size_t value)
*k: pointer to the key data (read-only), must be 16 bytes
*out: pointer to output data (write-only), outlen bytes must be allocated
outlen: length of the output in bytes, must be 8 or 16
*/
void siphash(const void * __restrict in, const size_t inlen, uint8_t * __restrict out) {
const auto* ni = (const unsigned char *)in;
uint64_t v0 = UINT64_C(0x736f6d6570736575);
uint64_t v1 = UINT64_C(0x646f72616e646f6d);
uint64_t v2 = UINT64_C(0x6c7967656e657261);
uint64_t v3 = UINT64_C(0x7465646279746573);
//uint64_t k0 = U8TO64_LE(kk);
//uint64_t k1 = U8TO64_LE(kk + 8);
constexpr auto key_ = make_key();
constexpr uint64_t k0 = key_.k0;
constexpr uint64_t k1 = key_.k1;
uint64_t m;
int i;
const uint8_t *end = ni + inlen - (inlen % sizeof(uint64_t));
const auto left = (uint32_t)(inlen & 7);
uint64_t b = ((uint64_t)inlen) << 56;
v3 ^= k1;
v2 ^= k0;
v1 ^= k1;
v0 ^= k0;
#if 0
if (outlen == 16)
v1 ^= 0xee;
#endif
for (; ni != end; ni += 8) {
m = U8TO64_LE(ni);
v3 ^= m;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
v0 ^= m;
}
switch (left) {
case 7:
b |= ((uint64_t)ni[6]) << 48; [[fallthrough]];
case 6:
b |= ((uint64_t)ni[5]) << 40; [[fallthrough]];
case 5:
b |= ((uint64_t)ni[4]) << 32; [[fallthrough]];
case 4:
b |= ((uint64_t)ni[3]) << 24; [[fallthrough]];
case 3:
b |= ((uint64_t)ni[2]) << 16; [[fallthrough]];
case 2:
b |= ((uint64_t)ni[1]) << 8; [[fallthrough]];
case 1:
b |= ((uint64_t)ni[0]); [[fallthrough]];
case 0:
break;
}
v3 ^= b;
for (i = 0; i < cROUNDS; ++i)
SIPROUND;
v0 ^= b;
#if 0
if (outlen == 16)
v2 ^= 0xee;
else
#endif
v2 ^= 0xff;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out, b);
#if 0
if (outlen == 8)
return 0;
v1 ^= 0xdd;
TRACE;
for (i = 0; i < dROUNDS; ++i)
SIPROUND;
b = v0 ^ v1 ^ v2 ^ v3;
U64TO8_LE(out + 8, b);
#endif
}
} // namespace
size_t hash_buf(const void* __restrict buf, size_t size) noexcept
{
uint64_t ret;
siphash(buf, size, reinterpret_cast<uint8_t*>(&ret));
return (size_t)ret;
}
size_t hash_int(uint32_t x) noexcept
{
return hash_buf(&x, sizeof x);
}
size_t hash_int(uint64_t x) noexcept
{
return hash_buf(&x, sizeof x);
}
} // namespace floormat::SipHash
// NOLINTEND(*-switch-missing-default-case, *-multiway-paths-covered)
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