Revert changes to develop branch.

Simplest way to merge to master.

include/boost/functional/hash/extensions.hpp

@@ -13,11 +13,6 @@
 #if !defined(BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP)
 #define BOOST_FUNCTIONAL_HASH_EXTENSIONS_HPP
 
-#include <boost/config.hpp>
-#if defined(BOOST_HAS_PRAGMA_ONCE)
-#pragma once
-#endif
-
 #include <boost/functional/hash/hash.hpp>
 #include <boost/detail/container_fwd.hpp>
 #include <boost/utility/enable_if.hpp>
@@ -37,10 +32,18 @@
 #   include <memory>
 #endif
 
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
+#endif
+
 #if defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
 #include <boost/type_traits/is_array.hpp>
 #endif
 
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+#include <boost/type_traits/is_const.hpp>
+#endif
+
 namespace boost
 {
     template <class A, class B>
@@ -229,7 +232,11 @@ namespace boost
             template <class Array>
             struct inner
             {
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
                 static std::size_t call(Array const& v)
+#else
+                static std::size_t call(Array& v)
+#endif
                 {
                     const int size = sizeof(v) / sizeof(*v);
                     return boost::hash_range(v, v + size);
@@ -251,6 +258,7 @@ namespace boost
     //
 
 
+#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
 
     template <class T> struct hash
         : std::unary_function<T, std::size_t>
@@ -279,6 +287,93 @@ namespace boost
     };
 #endif
 
+#else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+
+    // On compilers without partial specialization, boost::hash<T>
+    // has already been declared to deal with pointers, so just
+    // need to supply the non-pointer version of hash_impl.
+
+    namespace hash_detail
+    {
+        template <bool IsPointer>
+        struct hash_impl;
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+
+        template <>
+        struct hash_impl<false>
+        {
+            template <class T>
+            struct inner
+                : std::unary_function<T, std::size_t>
+            {
+#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING)
+                std::size_t operator()(T const& val) const
+                {
+                    return hash_value(val);
+                }
+#else
+                std::size_t operator()(T const& val) const
+                {
+                    return hash_detail::call_hash<T>::call(val);
+                }
+#endif
+            };
+        };
+
+#else // Visual C++ 6.5
+
+        // Visual C++ 6.5 has problems with nested member functions and
+        // applying const to const types in templates. So we get this:
+
+        template <bool IsConst>
+        struct hash_impl_msvc
+        {
+            template <class T>
+            struct inner
+                : public std::unary_function<T, std::size_t>
+            {
+                std::size_t operator()(T const& val) const
+                {
+                    return hash_detail::call_hash<T const>::call(val);
+                }
+
+                std::size_t operator()(T& val) const
+                {
+                    return hash_detail::call_hash<T>::call(val);
+                }
+            };
+        };
+
+        template <>
+        struct hash_impl_msvc<true>
+        {
+            template <class T>
+            struct inner
+                : public std::unary_function<T, std::size_t>
+            {
+                std::size_t operator()(T& val) const
+                {
+                    return hash_detail::call_hash<T>::call(val);
+                }
+            };
+        };
+        
+        template <class T>
+        struct hash_impl_msvc2
+            : public hash_impl_msvc<boost::is_const<T>::value>
+                    ::BOOST_NESTED_TEMPLATE inner<T> {};
+        
+        template <>
+        struct hash_impl<false>
+        {
+            template <class T>
+            struct inner : public hash_impl_msvc2<T> {};
+        };
+
+#endif // Visual C++ 6.5
+    }
+#endif  // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
 }
 
 #endif