[PATCH] Add overflow checking to basic_string append and push_back

[Travis Vitek]

It appears that recent changes to string have accidentally removed some
overflow checking that used to be in the basic_string::append() and
push_back() methods. The following patch adds the checks back in.

Travis


2007-09-20  Travis Vitek  <[EMAIL PROTECTED]>

        * string (append): add integer overflow check
        (push_back): Same

===================================================================
--- string      (revision 576541)
+++ string      (working copy)
@@ -1088,6 +1088,11 @@
 inline void basic_string<_CharT, _Traits, _Allocator>::
 push_back (value_type __c)
 {
+    _RWSTD_REQUIRES (size () <= max_size () - 1,
+                     (_RWSTD_ERROR_LENGTH_ERROR,
+                      _RWSTD_FUNC ("basic_string::append(value_type)"),
+                      size (), max_size () - 1));
+
     const size_type __size = size () + 1;
 
     if (   capacity () < __size
@@ -1095,7 +1100,6 @@
         append (1, __c);
     else {
         traits_type::assign (_C_data [size ()], __c);
-        // append the terminating NUL character
         traits_type::assign (_C_data [__size], value_type ());
         _C_pref ()->_C_size._C_size = __size;
     }
@@ -1196,6 +1200,12 @@
 basic_string<_CharT, _Traits, _Allocator>::
 append (const_pointer __s, size_type __n)
 {
+    _RWSTD_REQUIRES (size () <= max_size () - __n,
+                     (_RWSTD_ERROR_LENGTH_ERROR,
+                      _RWSTD_FUNC
("basic_string::append(const_pointer,"
+                                   " size_type)"),
+                      size (), max_size () - __n));
+
     const size_type __newsize = size () + __n;
 
     if (   capacity () <= __newsize