Subject: [Boost-commit] svn:boost r80177 - in trunk: boost/functional/hash/detail libs/functional/hash/test
From: dnljms_at_[hidden]
Date: 2012-08-24 18:52:43
Author: danieljames
Date: 2012-08-24 18:52:42 EDT (Fri, 24 Aug 2012)
New Revision: 80177
URL: http://svn.boost.org/trac/boost/changeset/80177
Log:
Hash: A single unified algorithm for hashing floats.
Attempts to automatically use a binary hash for floats where it's known to
work, and then use the generic hash algorithm as a fallback.
Removed:
trunk/boost/functional/hash/detail/hash_float_generic.hpp
trunk/boost/functional/hash/detail/hash_float_x86.hpp
Text files modified:
trunk/boost/functional/hash/detail/hash_float.hpp | 182 ++++++++++++++++++++++++++++++++++++---
trunk/libs/functional/hash/test/Jamfile.v2 | 15 +++
2 files changed, 182 insertions(+), 15 deletions(-)
Modified: trunk/boost/functional/hash/detail/hash_float.hpp
==============================================================================
--- trunk/boost/functional/hash/detail/hash_float.hpp (original)
+++ trunk/boost/functional/hash/detail/hash_float.hpp 2012-08-24 18:52:42 EDT (Fri, 24 Aug 2012)
@@ -1,5 +1,5 @@
-// 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)
@@ -13,21 +13,19 @@
#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 +48,158 @@
# 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)) {
+ hash_float_combine(seed, *(std::size_t*) ptr);
+ 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 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
+ )
+ {
+ boost::uint32_t* ptr = (boost::uint32_t*)&v;
+ return (std::size_t) *ptr;
+ }
+
+
+ template <typename Float>
+ inline std::size_t float_hash_impl(Float v,
+ BOOST_DEDUCED_TYPENAME 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 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 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)
+ {
+ 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>
@@ -71,7 +221,7 @@
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 +253,7 @@
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 +262,8 @@
#undef BOOST_HASH_USE_FPCLASSIFY
+#if defined(BOOST_MSVC)
+#pragma warning(pop)
+#endif
+
#endif
Deleted: trunk/boost/functional/hash/detail/hash_float_generic.hpp
==============================================================================
--- trunk/boost/functional/hash/detail/hash_float_generic.hpp 2012-08-24 18:52:42 EDT (Fri, 24 Aug 2012)
+++ (empty file)
@@ -1,91 +0,0 @@
-
-// 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 general purpose hash function for non-zero floating point values.
-
-#if !defined(BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_GENERIC_HEADER)
-#define BOOST_FUNCTIONAL_HASH_DETAIL_HASH_FLOAT_GENERIC_HEADER
-
-#include <boost/functional/hash/detail/float_functions.hpp>
-#include <boost/integer/static_log2.hpp>
-#include <boost/functional/hash/detail/limits.hpp>
-
-#if defined(_MSC_VER) && (_MSC_VER >= 1020)
-# pragma once
-#endif
-
-#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
-
-namespace boost
-{
- namespace hash_detail
- {
- inline void hash_float_combine(std::size_t& seed, std::size_t value)
- {
- seed ^= value + (seed<<6) + (seed>>2);
- }
-
- 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;
- }
-
- 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));
- }
- }
-}
-
-#if defined(BOOST_MSVC)
-#pragma warning(pop)
-#endif
-
-#endif
Deleted: trunk/boost/functional/hash/detail/hash_float_x86.hpp
==============================================================================
--- trunk/boost/functional/hash/detail/hash_float_x86.hpp 2012-08-24 18:52:42 EDT (Fri, 24 Aug 2012)
+++ (empty file)
@@ -1,56 +0,0 @@
-
-// 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
Modified: trunk/libs/functional/hash/test/Jamfile.v2
==============================================================================
--- trunk/libs/functional/hash/test/Jamfile.v2 (original)
+++ trunk/libs/functional/hash/test/Jamfile.v2 2012-08-24 18:52:42 EDT (Fri, 24 Aug 2012)
@@ -1,5 +1,5 @@
-# Copyright 2005-2011 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)
@@ -66,4 +66,17 @@
[ run link_test.cpp link_test_2.cpp : : : <define>BOOST_HASH_NO_EXTENSIONS : no_ext_link_test ]
;
+# Tests to see if the floating point hash is using the binary hash.
+# Not run normally because on some platforms these should fail.
+test-suite functional/hash_no_generic_float
+ :
+ [ run hash_float_test.cpp
+ : : : <define>BOOST_HASH_DETAIL_TEST_WITHOUT_GENERIC
+ : hash_float_test_no_generic ]
+ [ run hash_long_double_test.cpp
+ : : : <define>BOOST_HASH_DETAIL_TEST_WITHOUT_GENERIC
+ : hash_long_double_test_no_generic ]
+ ;
+explicit functional/hash_no_generic_float ;
+
build-project ../examples ;