[Boost-commit] svn:boost r80177 - in trunk: boost/functional/hash/detail libs/functional/hash/test

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 ;