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#include "compat/defs.hpp"
#include "int-hash.hpp"
#include <bit>
namespace floormat {
namespace {
[[maybe_unused]]
CORRADE_ALWAYS_INLINE uint32_t FNVHash_32(uint32_t x)
{
const auto *str = (const char*)&x, *end = str + 4;
uint32_t hash = 0x811c9dc5u;
fm_UNROLL_4
for (; str != end; ++str)
{
hash *= 0x01000193u;
hash ^= (uint8_t)*str;
}
return hash;
}
CORRADE_ALWAYS_INLINE uint64_t FNVHash_64(uint64_t x)
{
const auto *str = (const char*)&x, *end = str + 8;
uint64_t hash = 0xcbf29ce484222325u;
fm_UNROLL_8
for (; str != end; ++str)
{
hash *= 0x100000001b3u;
hash ^= (uint8_t)*str;
}
return hash;
}
} // namespace
uint64_t fnvhash_32(const void* buf, size_t size)
{
const auto *str = (const char*)buf, *const end = str + size;
uint32_t hash = 0x811c9dc5u;
fm_UNROLL_8
for (; str != end; ++str)
{
hash *= 0x01000193u;
hash ^= (uint8_t)*str;
}
return hash;
}
uint64_t fnvhash_64(const void* buf, size_t size)
{
const auto *str = (const char*)buf, *const end = str + size;
uint64_t hash = 0xcbf29ce484222325u;
fm_UNROLL_4
for (; str != end; ++str)
{
hash *= 0x100000001b3u;
hash ^= (uint8_t)*str;
}
return hash;
}
size_t int_hash(uint32_t x) noexcept
{
if constexpr(sizeof(size_t) == 4)
return FNVHash_32(x);
else
return FNVHash_64(x);
}
size_t int_hash(uint64_t x) noexcept
{
return FNVHash_64(x);
}
} // namespace floormat
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