diff options
author | Boris Kolpackov <boris@codesynthesis.com> | 2011-06-28 17:17:23 +0200 |
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committer | Boris Kolpackov <boris@codesynthesis.com> | 2011-06-28 17:17:23 +0200 |
commit | b51965dddbed68f23c5e8c169c23c794313ce5f6 (patch) | |
tree | 37bbdf4e5b1cdd34ea0694a5abd1483d1de2b3af /cutl/details/boost/functional/hash/detail/hash_float_x86.hpp | |
parent | 5f06e7e30e4f511ce2fb27c5feefa6aeb6f00841 (diff) |
Add boost subset as an implementation detail
Diffstat (limited to 'cutl/details/boost/functional/hash/detail/hash_float_x86.hpp')
-rw-r--r-- | cutl/details/boost/functional/hash/detail/hash_float_x86.hpp | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/cutl/details/boost/functional/hash/detail/hash_float_x86.hpp b/cutl/details/boost/functional/hash/detail/hash_float_x86.hpp new file mode 100644 index 0000000..6a70556 --- /dev/null +++ b/cutl/details/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 <cutl/details/boost/cstdint.hpp> + +#if defined(_MSC_VER) && (_MSC_VER >= 1020) +# pragma once +#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); + } + + inline std::size_t float_hash_impl(float v) + { + cutl_details_boost::uint32_t* ptr = (cutl_details_boost::uint32_t*)&v; + std::size_t seed = *ptr; + return seed; + } + + inline std::size_t float_hash_impl(double v) + { + cutl_details_boost::uint32_t* ptr = (cutl_details_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) + { + cutl_details_boost::uint32_t* ptr = (cutl_details_boost::uint32_t*)&v; + std::size_t seed = *ptr++; + hash_float_combine(seed, *ptr++); + hash_float_combine(seed, *(cutl_details_boost::uint16_t*)ptr); + return seed; + } + } +} + +#endif |