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lammps/lib/kokkos/containers/src/impl/Kokkos_Functional_impl.hpp
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Kokkos_Functional_impl.hpp
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#ifndef KOKKOS_FUNCTIONAL_IMPL_HPP
#define KOKKOS_FUNCTIONAL_IMPL_HPP
#include <Kokkos_Macros.hpp>
#include <stdint.h>
namespace Kokkos { namespace Impl {
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. The author hereby disclaims copyright to this source code.
KOKKOS_FORCEINLINE_FUNCTION
uint32_t getblock32 ( const uint8_t * p, int i )
{
// used to avoid aliasing error which could cause errors with
// forced inlining
return ((uint32_t)p[i*4+0])
| ((uint32_t)p[i*4+1] << 8)
| ((uint32_t)p[i*4+2] << 16)
| ((uint32_t)p[i*4+3] << 24);
}
KOKKOS_FORCEINLINE_FUNCTION
uint32_t rotl32 ( uint32_t x, int8_t r )
{ return (x << r) | (x >> (32 - r)); }
KOKKOS_FORCEINLINE_FUNCTION
uint32_t fmix32 ( uint32_t h )
{
h ^= h >> 16;
h *= 0x85ebca6b;
h ^= h >> 13;
h *= 0xc2b2ae35;
h ^= h >> 16;
return h;
}
KOKKOS_INLINE_FUNCTION
uint32_t MurmurHash3_x86_32 ( const void * key, int len, uint32_t seed )
{
const uint8_t * data = (const uint8_t*)key;
const int nblocks = len / 4;
uint32_t h1 = seed;
const uint32_t c1 = 0xcc9e2d51;
const uint32_t c2 = 0x1b873593;
//----------
// body
for(int i=0; i<nblocks; ++i)
{
uint32_t k1 = getblock32(data,i);
k1 *= c1;
k1 = rotl32(k1,15);
k1 *= c2;
h1 ^= k1;
h1 = rotl32(h1,13);
h1 = h1*5+0xe6546b64;
}
//----------
// tail
const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
uint32_t k1 = 0;
switch(len & 3)
{
case 3: k1 ^= tail[2] << 16;
case 2: k1 ^= tail[1] << 8;
case 1: k1 ^= tail[0];
k1 *= c1; k1 = rotl32(k1,15); k1 *= c2; h1 ^= k1;
};
//----------
// finalization
h1 ^= len;
h1 = fmix32(h1);
return h1;
}
#if defined( __GNUC__ ) /* GNU C */ || \
defined( __GNUG__ ) /* GNU C++ */ || \
defined( __clang__ )
#define KOKKOS_MAY_ALIAS __attribute__((__may_alias__))
#else
#define KOKKOS_MAY_ALIAS
#endif
template <typename T>
KOKKOS_FORCEINLINE_FUNCTION
bool bitwise_equal(T const * const a_ptr, T const * const b_ptr)
{
typedef uint64_t KOKKOS_MAY_ALIAS T64;
typedef uint32_t KOKKOS_MAY_ALIAS T32;
typedef uint16_t KOKKOS_MAY_ALIAS T16;
typedef uint8_t KOKKOS_MAY_ALIAS T8;
enum {
NUM_8 = sizeof(T),
NUM_16 = NUM_8 / 2,
NUM_32 = NUM_8 / 4,
NUM_64 = NUM_8 / 8
};
union {
T const * const ptr;
T64 const * const ptr64;
T32 const * const ptr32;
T16 const * const ptr16;
T8 const * const ptr8;
} a = {a_ptr}, b = {b_ptr};
bool result = true;
for (int i=0; i < NUM_64; ++i) {
result = result && a.ptr64[i] == b.ptr64[i];
}
if ( NUM_64*2 < NUM_32 ) {
result = result && a.ptr32[NUM_64*2] == b.ptr32[NUM_64*2];
}
if ( NUM_32*2 < NUM_16 ) {
result = result && a.ptr16[NUM_32*2] == b.ptr16[NUM_32*2];
}
if ( NUM_16*2 < NUM_8 ) {
result = result && a.ptr8[NUM_16*2] == b.ptr8[NUM_16*2];
}
return result;
}
#undef KOKKOS_MAY_ALIAS
}} // namespace Kokkos::Impl
#endif //KOKKOS_FUNCTIONAL_IMPL_HPP
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