boost/boost/functional/hash/detail/hash_float.hpp

   1
   2 // Copyright 2005-2009 Daniel James.
   3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #if !defined(BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HEADER)
   7 #define BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_HEADER
   8
   9 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  10 # pragma once
  11 #endif
  12
  13 #include <boost/config.hpp>
  14 #include <boost/functional/hash/detail/float_functions.hpp>
  15 #include <boost/functional/hash/detail/limits.hpp>
  16 #include <boost/integer/static_log2.hpp>
  17 #include <boost/cstdint.hpp>
  18 #include <boost/assert.hpp>
  19
  20 // Include hash implementation for the current platform.
  21
  22 // Cygwn
  23 #if defined(__CYGWIN__)
  24 #  if defined(__i386__) || defined(_M_IX86)
  25 #    include <boost/functional/hash/detail/hash_float_x86.hpp>
  26 #  else
  27 #    include <boost/functional/hash/detail/hash_float_generic.hpp>
  28 #  endif
  29 #else
  30 #  include <boost/functional/hash/detail/hash_float_generic.hpp>
  31 #endif
  32
  33 // Can we use fpclassify?
  34
  35 // STLport
  36 #if defined(__SGI_STL_PORT) || defined(_STLPORT_VERSION)
  37 #define BOOST_HASH_USE_FPCLASSIFY 0
  38
  39 // GNU libstdc++ 3
  40 #elif defined(__GLIBCPP__) || defined(__GLIBCXX__)
  41 #  if (defined(__USE_ISOC99) || defined(_GLIBCXX_USE_C99_MATH)) && \
  42       !(defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__))
  43 #    define BOOST_HASH_USE_FPCLASSIFY 1
  44 #  else
  45 #    define BOOST_HASH_USE_FPCLASSIFY 0
  46 #  endif
  47
  48 // Everything else
  49 #else
  50 #  define BOOST_HASH_USE_FPCLASSIFY 0
  51 #endif
  52
  53 #if BOOST_HASH_USE_FPCLASSIFY
  54
  55 #include <boost/config/no_tr1/cmath.hpp>
  56
  57 namespace boost
  58 {
  59     namespace hash_detail
  60     {
  61         template <class T>
  62         inline std::size_t float_hash_value(T v)
  63         {
  64             using namespace std;
  65             switch (fpclassify(v)) {
  66             case FP_ZERO:
  67                 return 0;
  68             case FP_INFINITE:
  69                 return (std::size_t)(v > 0 ? -1 : -2);
  70             case FP_NAN:
  71                 return (std::size_t)(-3);
  72             case FP_NORMAL:
  73             case FP_SUBNORMAL:
  74                 return float_hash_impl(v);
  75             default:
  76                 BOOST_ASSERT(0);
  77                 return 0;
  78             }
  79         }
  80     }
  81 }
  82
  83 #else // !BOOST_HASH_USE_FPCLASSIFY
  84
  85 namespace boost
  86 {
  87     namespace hash_detail
  88     {
  89         template <class T>
  90         inline std::size_t float_hash_value(T v)
  91         {
  92             return v == 0 ? 0 : float_hash_impl(v);
  93         }
  94     }
  95 }
  96
  97 #endif // BOOST_HASH_USE_FPCLASSIFY
  98
  99 #undef BOOST_HASH_USE_FPCLASSIFY
 100
 101 #endif