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-rw-r--r--boost/functional/hash/detail/hash_float.hpp192
1 files changed, 174 insertions, 18 deletions
diff --git a/boost/functional/hash/detail/hash_float.hpp b/boost/functional/hash/detail/hash_float.hpp
index 194be1cae5..ee0ee87745 100644
--- a/boost/functional/hash/detail/hash_float.hpp
+++ b/boost/functional/hash/detail/hash_float.hpp
@@ -1,33 +1,31 @@
-// Copyright 2005-2009 Daniel James.
+// 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
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
#endif
-#include <boost/config.hpp>
#include <boost/functional/hash/detail/float_functions.hpp>
#include <boost/functional/hash/detail/limits.hpp>
+#include <boost/utility/enable_if.hpp>
#include <boost/integer/static_log2.hpp>
#include <boost/cstdint.hpp>
#include <boost/assert.hpp>
+#include <boost/limits.hpp>
+#include <cstring>
-// Include hash implementation for the current platform.
-
-// Cygwn
-#if defined(__CYGWIN__)
-# if defined(__i386__) || defined(_M_IX86)
-# include <boost/functional/hash/detail/hash_float_x86.hpp>
-# else
-# include <boost/functional/hash/detail/hash_float_generic.hpp>
-# endif
-#else
-# include <boost/functional/hash/detail/hash_float_generic.hpp>
+#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?
@@ -50,6 +48,153 @@
# define BOOST_HASH_USE_FPCLASSIFY 0
#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);
+ }
+
+ ////////////////////////////////////////////////////////////////////////
+ // 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, unsigned digits, unsigned max_exponent>
+ struct enable_binary_hash
+ {
+ BOOST_STATIC_CONSTANT(bool, value =
+ std::numeric_limits<Float>::is_iec559 &&
+ std::numeric_limits<Float>::digits == digits &&
+ std::numeric_limits<Float>::radix == 2 &&
+ std::numeric_limits<Float>::max_exponent == max_exponent);
+ };
+
+ template <typename Float>
+ inline std::size_t float_hash_impl(Float v,
+ BOOST_DEDUCED_TYPENAME boost::enable_if_c<
+ enable_binary_hash<Float, 24, 128>::value,
+ std::size_t>::type)
+ {
+ return hash_binary((char*) &v, 4);
+ }
+
+
+ template <typename Float>
+ inline std::size_t float_hash_impl(Float v,
+ BOOST_DEDUCED_TYPENAME boost::enable_if_c<
+ enable_binary_hash<Float, 53, 1024>::value,
+ std::size_t>::type)
+ {
+ return hash_binary((char*) &v, 8);
+ }
+
+ template <typename Float>
+ inline std::size_t float_hash_impl(Float v,
+ BOOST_DEDUCED_TYPENAME boost::enable_if_c<
+ enable_binary_hash<Float, 64, 16384>::value,
+ std::size_t>::type)
+ {
+ return hash_binary((char*) &v, 10);
+ }
+
+ template <typename Float>
+ inline std::size_t float_hash_impl(Float v,
+ BOOST_DEDUCED_TYPENAME boost::enable_if_c<
+ enable_binary_hash<Float, 113, 16384>::value,
+ std::size_t>::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)
+ {
+ boost::hash_detail::call_frexp<T> frexp;
+ 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 *
+ 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 <boost/config/no_tr1/cmath.hpp>
@@ -61,8 +206,15 @@ namespace boost
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)) {
+ switch (fpclassify(v))
+#endif
+ {
case FP_ZERO:
return 0;
case FP_INFINITE:
@@ -71,7 +223,7 @@ namespace boost
return (std::size_t)(-3);
case FP_NORMAL:
case FP_SUBNORMAL:
- return float_hash_impl(v);
+ return float_hash_impl(v, 0);
default:
BOOST_ASSERT(0);
return 0;
@@ -103,7 +255,7 @@ namespace boost
template <class T>
inline std::size_t float_hash_value(T v)
{
- return boost::hash_detail::is_zero(v) ? 0 : float_hash_impl(v);
+ return boost::hash_detail::is_zero(v) ? 0 : float_hash_impl(v, 0);
}
}
}
@@ -112,4 +264,8 @@ namespace boost
#undef BOOST_HASH_USE_FPCLASSIFY
+#if defined(BOOST_MSVC)
+#pragma warning(pop)
+#endif
+
#endif