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Diffstat (limited to '3rdParty/Boost/src/boost/functional/hash/detail/hash_float_x86.hpp')
-rw-r--r-- | 3rdParty/Boost/src/boost/functional/hash/detail/hash_float_x86.hpp | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/3rdParty/Boost/src/boost/functional/hash/detail/hash_float_x86.hpp b/3rdParty/Boost/src/boost/functional/hash/detail/hash_float_x86.hpp new file mode 100644 index 0000000..b39bb0d --- /dev/null +++ b/3rdParty/Boost/src/boost/functional/hash/detail/hash_float_x86.hpp @@ -0,0 +1,56 @@ + +// Copyright 2005-2009 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) + +// A non-portable hash function form non-zero floats on x86. +// +// Even if you're on an x86 platform, this might not work if their floating +// point isn't set up as this expects. So this should only be used if it's +// absolutely certain that it will work. + +#if !defined(BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_X86_HEADER) +#define BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_X86_HEADER + +#include <boost/cstdint.hpp> + +#if defined(_MSC_VER) && (_MSC_VER >= 1020) +# pragma once +#endif + +namespace boost +{ + namespace hash_detail + { + inline void hash_float_combine(std::size_t& seed, std::size_t value) + { + seed ^= value + (seed<<6) + (seed>>2); + } + + inline std::size_t float_hash_impl(float v) + { + boost::uint32_t* ptr = (boost::uint32_t*)&v; + std::size_t seed = *ptr; + return seed; + } + + inline std::size_t float_hash_impl(double v) + { + boost::uint32_t* ptr = (boost::uint32_t*)&v; + std::size_t seed = *ptr++; + hash_float_combine(seed, *ptr); + return seed; + } + + inline std::size_t float_hash_impl(long double v) + { + boost::uint32_t* ptr = (boost::uint32_t*)&v; + std::size_t seed = *ptr++; + hash_float_combine(seed, *ptr++); + hash_float_combine(seed, *(boost::uint16_t*)ptr); + return seed; + } + } +} + +#endif |