From cd0167d6b8bc3cadab3b674e7f5304d8322c77d8 Mon Sep 17 00:00:00 2001
From: Antony Polukhin <antoshkka@gmail.com>
Date: Tue, 31 May 2011 20:46:37 +0000
Subject: [PATCH] Fixes #5585 and adds test on it

[SVN r72315]
---
 include/boost/lexical_cast.hpp | 28 ++++++++++++++++++++++++----
 lexical_cast_test.cpp          |  3 +++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/include/boost/lexical_cast.hpp b/include/boost/lexical_cast.hpp
index c1b083b..ddd7398 100644
--- a/include/boost/lexical_cast.hpp
+++ b/include/boost/lexical_cast.hpp
@@ -654,6 +654,7 @@ namespace boost
                 unsigned char current_grouping = 0;
                 CharT const thousands_sep = np.thousands_sep();
                 char remained = grouping[current_grouping] - 1;
+                bool shall_we_return = true;
 
                 for(;end>=begin; --end)
                 {
@@ -671,12 +672,31 @@ namespace boost
                         multiplier *= 10;
                         --remained;
                     } else {
-                        if ( !Traits::eq(*end, thousands_sep) || begin == end ) return false;
-                        if (current_grouping < grouping_size-1 ) ++current_grouping;
-                        remained = grouping[current_grouping];
+                        if ( !Traits::eq(*end, thousands_sep) ) //|| begin == end ) return false;
+                        {
+                            /*
+                             * According to Programming languages - C++
+                             * Digit grouping is checked. That is, the positions of discarded
+                             * separators is examined for consistency with
+                             * use_facet<numpunct<charT> >(loc ).grouping()
+                             *
+                             * BUT what if there is no separators at all and grouping()
+                             * is not empty? Well, we have no extraced separators, so we
+                             * won`t check them for consistency. This will allow us to
+                             * work with "C" locale from other locales
+                             */
+                            shall_we_return = false;
+                            break;
+                        } else {
+                            if ( begin == end ) return false;
+                            if (current_grouping < grouping_size-1 ) ++current_grouping;
+                            remained = grouping[current_grouping];
+                        }
                     }
                 }
-            } else
+
+                if (shall_we_return) return true;
+            }
 #endif
             {
                 while ( begin <= end )
diff --git a/lexical_cast_test.cpp b/lexical_cast_test.cpp
index f88017f..f20994e 100644
--- a/lexical_cast_test.cpp
+++ b/lexical_cast_test.cpp
@@ -677,6 +677,9 @@ void test_conversion_from_to_integral_for_locale()
                 , bad_lexical_cast);
         BOOST_CHECK_THROW(lexical_cast<T>( std::string("100") + np.thousands_sep() ), bad_lexical_cast);
         BOOST_CHECK_THROW(lexical_cast<T>( np.thousands_sep() + std::string("100") ), bad_lexical_cast);
+
+        // Exception must not be thrown, when we are using no separators at all
+        BOOST_CHECK( lexical_cast<T>("10000") == static_cast<T>(10000) );
     }
 
     test_conversion_from_integral_to_integral<T>();