From 970aa9f07d77f10444bd78367dbc6eaafe743e9a Mon Sep 17 00:00:00 2001
From: Shane Grant <w.shane.grant@gmail.com>
Date: Sat, 8 Mar 2014 11:08:48 -0800
Subject: [PATCH] Fixes empty string serialization for debug in VS (#69)

Previously we took the address of the dereferenced begin() iterator
on a string to get the pointer to its data; we now just const_cast
the pointer that is the result of calling data().

The original reason for using the iterator over something like data()
was to avoid the const_cast and to ensure that any copy on write
mechanisms were used, but this doesn't seem necessary given that we
call resize() immediately prior to this.  Valgrind shows no problems
with the new method.  Also added unit tests for this case to string.
---
 include/cereal/types/string.hpp | 2 +-
 sandbox_vs.cpp                  | 2 +-
 unittests.cpp                   | 7 ++++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/include/cereal/types/string.hpp b/include/cereal/types/string.hpp
index 94c6d661c..5dbf35cdf 100644
--- a/include/cereal/types/string.hpp
+++ b/include/cereal/types/string.hpp
@@ -53,7 +53,7 @@ namespace cereal
     size_type size;
     ar( make_size_tag( size ) );
     str.resize(static_cast<std::size_t>(size));
-    ar( binary_data( &(*str.begin()), static_cast<std::size_t>(size) * sizeof(CharT) ) );
+    ar( binary_data( const_cast<CharT *>( str.data() ), static_cast<std::size_t>(size) * sizeof( CharT ) ) );
   }
 } // namespace cereal
 
diff --git a/sandbox_vs.cpp b/sandbox_vs.cpp
index 39d6cb090..2b80c057c 100644
--- a/sandbox_vs.cpp
+++ b/sandbox_vs.cpp
@@ -32,7 +32,7 @@
 #include <cereal/types/vector.hpp>
 
 #include <cereal/archives/binary.hpp>
-//#include <cereal/archives/portable_binary.hpp>
+#include <cereal/archives/portable_binary.hpp>
 #include <cereal/archives/xml.hpp>
 #include <cereal/archives/json.hpp>
 
diff --git a/unittests.cpp b/unittests.cpp
index 468a8e1a9..2ea49faec 100644
--- a/unittests.cpp
+++ b/unittests.cpp
@@ -1892,24 +1892,29 @@ void test_string_basic()
 
   for(size_t i=0; i<100; ++i)
   {
-    std::basic_string<char> o_string        = random_basic_string<char>(gen);
+    std::basic_string<char> o_string  = random_basic_string<char>(gen);
+    std::basic_string<char> o_string2 = "";
 
     std::ostringstream os;
     {
       OArchive oar(os);
       oar(o_string);
+      oar(o_string2);
     }
 
     std::basic_string<char> i_string;
+    std::basic_string<char> i_string2;
 
     std::istringstream is(os.str());
     {
       IArchive iar(is);
 
       iar(i_string);
+      iar(i_string2);
     }
 
     BOOST_CHECK_EQUAL(i_string, o_string);
+    BOOST_CHECK_EQUAL(i_string2, o_string2);
   }
 }