libcruft-util/hash.hpp

53 lines
1.8 KiB
C++

/*
* This file is part of libgim.
*
* Waif is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* Waif is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with libgim. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2010 Danny Robson <danny@blubinc.net>
*/
#ifndef __UTIL_HASH_HPP
#define __UTIL_HASH_HPP
#include <cstdint>
#include <cstdlib>
// All hashes are unsuitable for cryptographic operations nnless noted.
namespace util {
// Fast integer mixing operations by Thomas Wang.
uint32_t wang32 (uint32_t key);
uint64_t wang64 (uint64_t key);
// Fast and general hashing using FNV-1a
uint32_t fnv1a32 (const void *, size_t);
uint64_t fnv1a64 (const void *, size_t);
// General hashes for when you really just don't care about implementation
inline uint32_t hash (uint32_t key) { return wang32 (key); }
inline int32_t hash ( int32_t key) { return (int32_t) hash ((uint32_t)key); }
inline uint64_t hash (uint64_t key) { return wang64 (key); }
inline int64_t hash ( int64_t key) { return (int64_t) hash ((uint64_t)key); }
inline uintptr_t hash (const void *key) {
return sizeof (uintptr_t) == 32 ? wang32 (reinterpret_cast<uintptr_t> (key)) :
wang64 (reinterpret_cast<uintptr_t> (key));
}
}
#endif