sstream.tcc (overflow): Instead of calling str()...

2003-05-01  Paolo Carlini  <pcarlini@unitus.it>

	* include/bits/sstream.tcc (overflow): Instead of calling
	str(), then _M_string.reserve, thus copying the contents
	of the current buffer two times, just copy the latter in
	a temporary, then use the 'swap trick'.

From-SVN: r66358

libstdc++-v3/ChangeLog

 2003-05-01  Paolo Carlini  <pcarlini@unitus.it>
 
+	* include/bits/sstream.tcc (overflow): Instead of calling
+	str(), then _M_string.reserve, thus copying the contents
+	of the current buffer two times, just copy the latter in
+	a temporary, then use the 'swap trick'.
+
+2003-05-01  Paolo Carlini  <pcarlini@unitus.it>
+
 	* include/std/std_sstream.h (str()): Revert the best of the
 	previous 'improvement', incorrect due to the COW nature of
 	v3 basic_string; simplify.

libstdc++-v3/include/bits/sstream.tcc

@@ -100,11 +100,15 @@ namespace std
       // Order these tests done in is unspecified by the standard.
       if (!__testput)
 	{
-	  // Force-allocate, re-sync.
-	  _M_string = this->str();
 	  // In virtue of DR 169 (TC) we are allowed to grow more than
 	  // one char. That's easy to implement thanks to the exponential
 	  // growth policy builtin into basic_string.
+	  __string_type __tmp;
+	  __tmp.reserve(__len);
+	  __tmp.assign(_M_string.data(),
+		       this->_M_out_end - this->_M_out_beg);
+	  _M_string.swap(__tmp);
+	  // Just to be sure...
 	  _M_string.reserve(__len);
 	  _M_really_sync(const_cast<char_type*>(_M_string.data()),
 			 this->_M_in_cur - this->_M_in_beg,