From 314f6dcfe061e4435ee33d70e1672810a2be3bb5 Mon Sep 17 00:00:00 2001
From: Marshall Clow <marshall@idio.com>
Date: Thu, 19 Jul 2012 15:12:33 +0000
Subject: [PATCH] Merge changes from [79588] to Release; fixes a unhex bug

[SVN r79604]
---
 include/boost/algorithm/hex.hpp | 36 +++++++++++++--------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/include/boost/algorithm/hex.hpp b/include/boost/algorithm/hex.hpp
index b6b1548..3f3c0c6 100644
--- a/include/boost/algorithm/hex.hpp
+++ b/include/boost/algorithm/hex.hpp
@@ -110,33 +110,25 @@ namespace detail {
       typedef T value_type;
   };
 
-//  Output Iterators have a value type of 'void'. Kinda sucks. 
-//  We special case some output iterators, but we can't enumerate them all.
-//  If we can't figure it out, we assume that you want to output chars.
-//  If you don't, pass in an iterator with a real value_type.
-    template <typename T> struct value_type_or_char       { typedef T value_type; };
-    template <>           struct value_type_or_char<void> { typedef char value_type; };
-    
-//  All in one step
-    template <typename Iterator> 
-    struct iterator_value_type {
-//        typedef typename value_type_or_char<typename hex_iterator_traits<Iterator>::value_type>::value_type value_type;
-        typedef typename hex_iterator_traits<Iterator>::value_type value_type;
-        };
-        
+	template <typename Iterator> 
+	bool iter_end ( Iterator current, Iterator last ) { return current == last; }
+	
+	template <typename T>
+	bool ptr_end ( const T* ptr, const T* /*end*/ ) { return *ptr == '\0'; }
+	
 //  What can we assume here about the inputs?
 //      is std::iterator_traits<InputIterator>::value_type always 'char' ?
 //  Could it be wchar_t, say? Does it matter?
 //      We are assuming ASCII for the values - but what about the storage?
-    template <typename InputIterator, typename OutputIterator>
-    typename boost::enable_if<boost::is_integral<typename iterator_value_type<OutputIterator>::value_type>, OutputIterator>::type
-    decode_one ( InputIterator &first, InputIterator last, OutputIterator out ) {
-        typedef typename iterator_value_type<OutputIterator>::value_type T;
+    template <typename InputIterator, typename OutputIterator, typename EndPred>
+    typename boost::enable_if<boost::is_integral<typename hex_iterator_traits<OutputIterator>::value_type>, OutputIterator>::type
+    decode_one ( InputIterator &first, InputIterator last, OutputIterator out, EndPred pred ) {
+        typedef typename hex_iterator_traits<OutputIterator>::value_type T;
         T res (0);
 
     //  Need to make sure that we get can read that many chars here.
         for ( std::size_t i = 0; i < 2 * sizeof ( T ); ++i, ++first ) {
-            if ( first == last ) 
+            if ( pred ( first, last )) 
                 BOOST_THROW_EXCEPTION (not_enough_input ());
             res = ( 16 * res ) + hex_char_to_int (static_cast<char> (*first));
             }
@@ -205,7 +197,7 @@ hex ( const Range &r, OutputIterator out ) {
 template <typename InputIterator, typename OutputIterator>
 OutputIterator unhex ( InputIterator first, InputIterator last, OutputIterator out ) {
     while ( first != last )
-        out = detail::decode_one ( first, last, out );
+        out = detail::decode_one ( first, last, out, detail::iter_end<InputIterator> );
     return out;
     }
 
@@ -219,12 +211,12 @@ OutputIterator unhex ( InputIterator first, InputIterator last, OutputIterator o
 /// \note           Based on the MySQL function of the same name
 template <typename T, typename OutputIterator>
 OutputIterator unhex ( const T *ptr, OutputIterator out ) {
-    typedef typename detail::iterator_value_type<OutputIterator>::value_type OutputType;
+    typedef typename detail::hex_iterator_traits<OutputIterator>::value_type OutputType;
 //  If we run into the terminator while decoding, we will throw a
 //      malformed input exception. It would be nicer to throw a 'Not enough input'
 //      exception - but how much extra work would that require?
     while ( *ptr )
-        out = detail::decode_one ( ptr, (const T *) NULL, out );
+        out = detail::decode_one ( ptr, (const T *) NULL, out, detail::ptr_end<T> );
     return out;
     }