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// Copyright 2005-2012 Daniel James.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#if !defined(BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HEADER)
#define BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HEADER
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma once
#endif
#include <cutl/details/boost/config.hpp>
#include <cutl/details/boost/functional/hash/detail/float_functions.hpp>
#include <cutl/details/boost/functional/hash/detail/limits.hpp>
#include <cutl/details/boost/utility/enable_if.hpp>
#include <cutl/details/boost/integer/static_log2.hpp>
#include <cutl/details/boost/cstdint.hpp>
#include <cutl/details/boost/assert.hpp>
#include <cutl/details/boost/limits.hpp>
#include <cstring>
#if defined(BOOST_MSVC)
#pragma warning(push)
#if BOOST_MSVC >= 1400
#pragma warning(disable:6294) // Ill-defined for-loop: initial condition does
// not satisfy test. Loop body not executed
#endif
#endif
// Can we use fpclassify?
// STLport
#if defined(__SGI_STL_PORT) || defined(_STLPORT_VERSION)
#define BOOST_HASH_USE_FPCLASSIFY 0
// GNU libstdc++ 3
#elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
# if (defined(__USE_ISOC99) || defined(_GLIBCXX_USE_C99_MATH)) && \
!(defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__))
# define BOOST_HASH_USE_FPCLASSIFY 1
# else
# define BOOST_HASH_USE_FPCLASSIFY 0
# endif
// Everything else
#else
# define BOOST_HASH_USE_FPCLASSIFY 0
#endif
namespace cutl_details_boost
{
namespace hash_detail
{
inline void hash_float_combine(std::size_t& seed, std::size_t value)
{
seed ^= value + (seed<<6) + (seed>>2);
}
////////////////////////////////////////////////////////////////////////
// Binary hash function
//
// Only used for floats with known iec559 floats, and certain values in
// numeric_limits
inline std::size_t hash_binary(char* ptr, std::size_t length)
{
std::size_t seed = 0;
if (length >= sizeof(std::size_t)) {
seed = *(std::size_t*) ptr;
length -= sizeof(std::size_t);
ptr += sizeof(std::size_t);
while(length >= sizeof(std::size_t)) {
std::size_t buffer = 0;
std::memcpy(&buffer, ptr, sizeof(std::size_t));
hash_float_combine(seed, buffer);
length -= sizeof(std::size_t);
ptr += sizeof(std::size_t);
}
}
if (length > 0) {
std::size_t buffer = 0;
std::memcpy(&buffer, ptr, length);
hash_float_combine(seed, buffer);
}
return seed;
}
template <typename Float>
inline std::size_t float_hash_impl(Float v,
BOOST_DEDUCED_TYPENAME cutl_details_boost::enable_if_c<
std::numeric_limits<Float>::is_iec559 &&
std::numeric_limits<Float>::digits == 24 &&
std::numeric_limits<Float>::radix == 2 &&
std::numeric_limits<Float>::max_exponent == 128,
int>::type
)
{
return hash_binary((char*) &v, 4);
}
template <typename Float>
inline std::size_t float_hash_impl(Float v,
BOOST_DEDUCED_TYPENAME cutl_details_boost::enable_if_c<
std::numeric_limits<Float>::is_iec559 &&
std::numeric_limits<Float>::digits == 53 &&
std::numeric_limits<Float>::radix == 2 &&
std::numeric_limits<Float>::max_exponent == 1024,
int>::type
)
{
return hash_binary((char*) &v, 8);
}
template <typename Float>
inline std::size_t float_hash_impl(Float v,
BOOST_DEDUCED_TYPENAME cutl_details_boost::enable_if_c<
std::numeric_limits<Float>::is_iec559 &&
std::numeric_limits<Float>::digits == 64 &&
std::numeric_limits<Float>::radix == 2 &&
std::numeric_limits<Float>::max_exponent == 16384,
int>::type
)
{
return hash_binary((char*) &v, 10);
}
template <typename Float>
inline std::size_t float_hash_impl(Float v,
BOOST_DEDUCED_TYPENAME cutl_details_boost::enable_if_c<
std::numeric_limits<Float>::is_iec559 &&
std::numeric_limits<Float>::digits == 113 &&
std::numeric_limits<Float>::radix == 2 &&
std::numeric_limits<Float>::max_exponent == 16384,
int>::type
)
{
return hash_binary((char*) &v, 16);
}
////////////////////////////////////////////////////////////////////////
// Portable hash function
//
// Used as a fallback when the binary hash function isn't supported.
template <class T>
inline std::size_t float_hash_impl2(T v)
{
cutl_details_boost::hash_detail::call_frexp<T> frexp;
cutl_details_boost::hash_detail::call_ldexp<T> ldexp;
int exp = 0;
v = frexp(v, &exp);
// A postive value is easier to hash, so combine the
// sign with the exponent and use the absolute value.
if(v < 0) {
v = -v;
exp += limits<T>::max_exponent -
limits<T>::min_exponent;
}
v = ldexp(v, limits<std::size_t>::digits);
std::size_t seed = static_cast<std::size_t>(v);
v -= static_cast<T>(seed);
// ceiling(digits(T) * log2(radix(T))/ digits(size_t)) - 1;
std::size_t const length
= (limits<T>::digits *
cutl_details_boost::static_log2<limits<T>::radix>::value
+ limits<std::size_t>::digits - 1)
/ limits<std::size_t>::digits;
for(std::size_t i = 0; i != length; ++i)
{
v = ldexp(v, limits<std::size_t>::digits);
std::size_t part = static_cast<std::size_t>(v);
v -= static_cast<T>(part);
hash_float_combine(seed, part);
}
hash_float_combine(seed, exp);
return seed;
}
#if !defined(BOOST_HASH_DETAIL_TEST_WITHOUT_GENERIC)
template <class T>
inline std::size_t float_hash_impl(T v, ...)
{
typedef BOOST_DEDUCED_TYPENAME select_hash_type<T>::type type;
return float_hash_impl2(static_cast<type>(v));
}
#endif
}
}
#if BOOST_HASH_USE_FPCLASSIFY
#include <cutl/details/boost/config/no_tr1/cmath.hpp>
namespace cutl_details_boost
{
namespace hash_detail
{
template <class T>
inline std::size_t float_hash_value(T v)
{
#if defined(fpclassify)
switch (fpclassify(v))
#elif BOOST_HASH_CONFORMANT_FLOATS
switch (std::fpclassify(v))
#else
using namespace std;
switch (fpclassify(v))
#endif
{
case FP_ZERO:
return 0;
case FP_INFINITE:
return (std::size_t)(v > 0 ? -1 : -2);
case FP_NAN:
return (std::size_t)(-3);
case FP_NORMAL:
case FP_SUBNORMAL:
return float_hash_impl(v, 0);
default:
BOOST_ASSERT(0);
return 0;
}
}
}
}
#else // !BOOST_HASH_USE_FPCLASSIFY
namespace cutl_details_boost
{
namespace hash_detail
{
template <class T>
inline bool is_zero(T v)
{
#if !defined(__GNUC__)
return v == 0;
#else
// GCC's '-Wfloat-equal' will complain about comparing
// v to 0, but because it disables warnings for system
// headers it won't complain if you use std::equal_to to
// compare with 0. Resulting in this silliness:
return std::equal_to<T>()(v, 0);
#endif
}
template <class T>
inline std::size_t float_hash_value(T v)
{
return cutl_details_boost::hash_detail::is_zero(v) ? 0 : float_hash_impl(v, 0);
}
}
}
#endif // BOOST_HASH_USE_FPCLASSIFY
#undef BOOST_HASH_USE_FPCLASSIFY
#if defined(BOOST_MSVC)
#pragma warning(pop)
#endif
#endif
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