GRK/dependencies/physx-4.1/source/foundation/include/PsHash.h

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2022-01-12 16:07:16 +01:00
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// * Neither the name of NVIDIA CORPORATION nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Copyright (c) 2008-2019 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
#ifndef PSFOUNDATION_PSHASH_H
#define PSFOUNDATION_PSHASH_H
#include "Ps.h"
#include "PsBasicTemplates.h"
#if PX_VC
#pragma warning(push)
#pragma warning(disable : 4302)
#endif
#if PX_LINUX
#include "foundation/PxSimpleTypes.h"
#endif
/*!
Central definition of hash functions
*/
namespace physx
{
namespace shdfnd
{
// Hash functions
// Thomas Wang's 32 bit mix
// http://www.cris.com/~Ttwang/tech/inthash.htm
PX_FORCE_INLINE uint32_t hash(const uint32_t key)
{
uint32_t k = key;
k += ~(k << 15);
k ^= (k >> 10);
k += (k << 3);
k ^= (k >> 6);
k += ~(k << 11);
k ^= (k >> 16);
return uint32_t(k);
}
PX_FORCE_INLINE uint32_t hash(const int32_t key)
{
return hash(uint32_t(key));
}
// Thomas Wang's 64 bit mix
// http://www.cris.com/~Ttwang/tech/inthash.htm
PX_FORCE_INLINE uint32_t hash(const uint64_t key)
{
uint64_t k = key;
k += ~(k << 32);
k ^= (k >> 22);
k += ~(k << 13);
k ^= (k >> 8);
k += (k << 3);
k ^= (k >> 15);
k += ~(k << 27);
k ^= (k >> 31);
return uint32_t(UINT32_MAX & k);
}
#if PX_APPLE_FAMILY
// hash for size_t, to make gcc happy
PX_INLINE uint32_t hash(const size_t key)
{
#if PX_P64_FAMILY
return hash(uint64_t(key));
#else
return hash(uint32_t(key));
#endif
}
#endif
// Hash function for pointers
PX_INLINE uint32_t hash(const void* ptr)
{
#if PX_P64_FAMILY
return hash(uint64_t(ptr));
#else
return hash(uint32_t(UINT32_MAX & size_t(ptr)));
#endif
}
// Hash function for pairs
template <typename F, typename S>
PX_INLINE uint32_t hash(const Pair<F, S>& p)
{
uint32_t seed = 0x876543;
uint32_t m = 1000007;
return hash(p.second) ^ (m * (hash(p.first) ^ (m * seed)));
}
// hash object for hash map template parameter
template <class Key>
struct Hash
{
uint32_t operator()(const Key& k) const
{
return hash(k);
}
bool equal(const Key& k0, const Key& k1) const
{
return k0 == k1;
}
};
// specialization for strings
template <>
struct Hash<const char*>
{
public:
uint32_t operator()(const char* _string) const
{
// "DJB" string hash
const uint8_t* string = reinterpret_cast<const uint8_t*>(_string);
uint32_t h = 5381;
for(const uint8_t* ptr = string; *ptr; ptr++)
h = ((h << 5) + h) ^ uint32_t(*ptr);
return h;
}
bool equal(const char* string0, const char* string1) const
{
return !strcmp(string0, string1);
}
};
} // namespace shdfnd
} // namespace physx
#if PX_VC
#pragma warning(pop)
#endif
#endif // #ifndef PSFOUNDATION_PSHASH_H