ResInsight/ApplicationLibCode/Commands/HoloLensCommands/farmhash/farmhash.h
2021-01-11 15:27:45 +01:00

354 lines
12 KiB
C++

// Copyright (c) 2014 Google, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
// FarmHash, by Geoff Pike
//
// http://code.google.com/p/farmhash/
//
// This file provides a few functions for hashing strings and other
// data. All of them are high-quality functions in the sense that
// they do well on standard tests such as Austin Appleby's SMHasher.
// They're also fast. FarmHash is the successor to CityHash.
//
// Functions in the FarmHash family are not suitable for cryptography.
//
// WARNING: This code has been only lightly tested on big-endian platforms!
// It is known to work well on little-endian platforms that have a small penalty
// for unaligned reads, such as current Intel and AMD moderate-to-high-end CPUs.
// It should work on all 32-bit and 64-bit platforms that allow unaligned reads;
// bug reports are welcome.
//
// By the way, for some hash functions, given strings a and b, the hash
// of a+b is easily derived from the hashes of a and b. This property
// doesn't hold for any hash functions in this file.
#ifndef FARM_HASH_H_
#define FARM_HASH_H_
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h> // for memcpy and memset
#include <utility>
#ifndef NAMESPACE_FOR_HASH_FUNCTIONS
#define NAMESPACE_FOR_HASH_FUNCTIONS util
#endif
namespace NAMESPACE_FOR_HASH_FUNCTIONS
{
#if defined( FARMHASH_UINT128_T_DEFINED )
#if defined( __clang__ )
#if !defined( uint128_t )
#define uint128_t __uint128_t
#endif
#endif
inline uint64_t Uint128Low64( const uint128_t x )
{
return static_cast<uint64_t>( x );
}
inline uint64_t Uint128High64( const uint128_t x )
{
return static_cast<uint64_t>( x >> 64 );
}
inline uint128_t Uint128( uint64_t lo, uint64_t hi )
{
return lo + ( ( (uint128_t)hi ) << 64 );
}
#else
typedef std::pair<uint64_t, uint64_t> uint128_t;
inline uint64_t Uint128Low64( const uint128_t x )
{
return x.first;
}
inline uint64_t Uint128High64( const uint128_t x )
{
return x.second;
}
inline uint128_t Uint128( uint64_t lo, uint64_t hi )
{
return uint128_t( lo, hi );
}
#endif
// BASIC STRING HASHING
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
size_t Hash( const char* s, size_t len );
// Hash function for a byte array. Most useful in 32-bit binaries.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint32_t Hash32( const char* s, size_t len );
// Hash function for a byte array. For convenience, a 32-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint32_t Hash32WithSeed( const char* s, size_t len, uint32_t seed );
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint64_t Hash64( const char* s, size_t len );
// Hash function for a byte array. For convenience, a 64-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint64_t Hash64WithSeed( const char* s, size_t len, uint64_t seed );
// Hash function for a byte array. For convenience, two seeds are also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint64_t Hash64WithSeeds( const char* s, size_t len, uint64_t seed0, uint64_t seed1 );
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint128_t Hash128( const char* s, size_t len );
// Hash function for a byte array. For convenience, a 128-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
uint128_t Hash128WithSeed( const char* s, size_t len, uint128_t seed );
// BASIC NON-STRING HASHING
// Hash 128 input bits down to 64 bits of output.
// This is intended to be a reasonably good hash function.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
inline uint64_t Hash128to64( uint128_t x )
{
// Murmur-inspired hashing.
const uint64_t kMul = 0x9ddfea08eb382d69ULL;
uint64_t a = ( Uint128Low64( x ) ^ Uint128High64( x ) ) * kMul;
a ^= ( a >> 47 );
uint64_t b = ( Uint128High64( x ) ^ a ) * kMul;
b ^= ( b >> 47 );
b *= kMul;
return b;
}
// FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)
// Fingerprint function for a byte array. Most useful in 32-bit binaries.
uint32_t Fingerprint32( const char* s, size_t len );
// Fingerprint function for a byte array.
uint64_t Fingerprint64( const char* s, size_t len );
// Fingerprint function for a byte array.
uint128_t Fingerprint128( const char* s, size_t len );
// This is intended to be a good fingerprinting primitive.
// See below for more overloads.
inline uint64_t Fingerprint( uint128_t x )
{
// Murmur-inspired hashing.
const uint64_t kMul = 0x9ddfea08eb382d69ULL;
uint64_t a = ( Uint128Low64( x ) ^ Uint128High64( x ) ) * kMul;
a ^= ( a >> 47 );
uint64_t b = ( Uint128High64( x ) ^ a ) * kMul;
b ^= ( b >> 44 );
b *= kMul;
b ^= ( b >> 41 );
b *= kMul;
return b;
}
// This is intended to be a good fingerprinting primitive.
inline uint64_t Fingerprint( uint64_t x )
{
// Murmur-inspired hashing.
const uint64_t kMul = 0x9ddfea08eb382d69ULL;
uint64_t b = x * kMul;
b ^= ( b >> 44 );
b *= kMul;
b ^= ( b >> 41 );
b *= kMul;
return b;
}
#ifndef FARMHASH_NO_CXX_STRING
// Convenience functions to hash or fingerprint C++ strings.
// These require that Str::data() return a pointer to the first char
// (as a const char*) and that Str::length() return the string's length;
// they work with std::string, for example.
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline size_t Hash( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Hash( s.data(), s.length() );
}
// Hash function for a byte array. Most useful in 32-bit binaries.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint32_t Hash32( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Hash32( s.data(), s.length() );
}
// Hash function for a byte array. For convenience, a 32-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint32_t Hash32WithSeed( const Str& s, uint32_t seed )
{
assert( sizeof( s[0] ) == 1 );
return Hash32WithSeed( s.data(), s.length(), seed );
}
// Hash 128 input bits down to 64 bits of output.
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint64_t Hash64( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Hash64( s.data(), s.length() );
}
// Hash function for a byte array. For convenience, a 64-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint64_t Hash64WithSeed( const Str& s, uint64_t seed )
{
assert( sizeof( s[0] ) == 1 );
return Hash64WithSeed( s.data(), s.length(), seed );
}
// Hash function for a byte array. For convenience, two seeds are also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint64_t Hash64WithSeeds( const Str& s, uint64_t seed0, uint64_t seed1 )
{
assert( sizeof( s[0] ) == 1 );
return Hash64WithSeeds( s.data(), s.length(), seed0, seed1 );
}
// Hash function for a byte array.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint128_t Hash128( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Hash128( s.data(), s.length() );
}
// Hash function for a byte array. For convenience, a 128-bit seed is also
// hashed into the result.
// May change from time to time, may differ on different platforms, may differ
// depending on NDEBUG.
template <typename Str>
inline uint128_t Hash128WithSeed( const Str& s, uint128_t seed )
{
assert( sizeof( s[0] ) == 1 );
return Hash128( s.data(), s.length(), seed );
}
// FINGERPRINTING (i.e., good, portable, forever-fixed hash functions)
// Fingerprint function for a byte array. Most useful in 32-bit binaries.
template <typename Str>
inline uint32_t Fingerprint32( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Fingerprint32( s.data(), s.length() );
}
// Fingerprint 128 input bits down to 64 bits of output.
// Fingerprint function for a byte array.
template <typename Str>
inline uint64_t Fingerprint64( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Fingerprint64( s.data(), s.length() );
}
// Fingerprint function for a byte array.
template <typename Str>
inline uint128_t Fingerprint128( const Str& s )
{
assert( sizeof( s[0] ) == 1 );
return Fingerprint128( s.data(), s.length() );
}
#endif
} // namespace NAMESPACE_FOR_HASH_FUNCTIONS
/* gently define FARMHASH_BIG_ENDIAN when detected big-endian machine */
#if defined( __BIG_ENDIAN__ )
#if !defined( FARMHASH_BIG_ENDIAN )
#define FARMHASH_BIG_ENDIAN
#endif
#elif defined( __LITTLE_ENDIAN__ )
// nothing for little-endian
#elif defined( __BYTE_ORDER__ ) && defined( __ORDER_LITTLE_ENDIAN__ ) && ( __BYTE_ORDER == __ORDER_LITTLE_ENDIAN__ )
// nothing for little-endian
#elif defined( __BYTE_ORDER__ ) && defined( __ORDER_BIG_ENDIAN__ ) && ( __BYTE_ORDER == __ORDER_BIG_ENDIAN__ )
#if !defined( FARMHASH_BIG_ENDIAN )
#define FARMHASH_BIG_ENDIAN
#endif
#elif defined( __linux__ ) || defined( __CYGWIN__ ) || defined( __GNUC__ ) || defined( __GNU_LIBRARY__ )
#include <endian.h> // libc6-dev, GLIBC
#if BYTE_ORDER == BIG_ENDIAN
#if !defined( FARMHASH_BIG_ENDIAN )
#define FARMHASH_BIG_ENDIAN
#endif
#endif
#elif defined( __OpenBSD__ ) || defined( __NetBSD__ ) || defined( __FreeBSD__ ) || defined( __DragonFly__ ) || \
defined( __s390x__ )
#include <sys/endian.h>
#if BYTE_ORDER == BIG_ENDIAN
#if !defined( FARMHASH_BIG_ENDIAN )
#define FARMHASH_BIG_ENDIAN
#endif
#endif
#elif defined( _WIN32 )
// Windows is (currently) little-endian
#else
#error "Unable to determine endianness!"
#endif /* __BIG_ENDIAN__ */
#endif // FARM_HASH_H_