locale_facets.tcc (collate::do_transform): Rewrite to fix problems with long transformed strings.

2002-03-09  Paolo Carlini  <pcarlini@unitus.it>

        * include/bits/locale_facets.tcc (collate::do_transform):
        Rewrite to fix problems with long transformed strings.

From-SVN: r50500

libstdc++-v3/ChangeLog

+2002-03-09  Paolo Carlini  <pcarlini@unitus.it>
+
+	* include/bits/locale_facets.tcc (collate::do_transform):
+	Rewrite to fix problems with long transformed strings.
+
 2002-03-08  Benjamin Kosnik  <bkoz@redhat.com>
 
 	* c_locale_generic.cc: Move to...

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

@@ -1854,16 +1854,17 @@ namespace std
     collate<_CharT>::
     do_transform(const _CharT* __lo, const _CharT* __hi) const
     {
-      size_t __len = __hi - __lo;
+      size_t __len = (__hi - __lo) * 2;
+      // First try a buffer perhaps big enough.
       _CharT* __c = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT) * __len));
       size_t __res = _M_transform_helper(__c, __lo, __len);
+      // If the buffer was not large enough, try again with the correct size.
       if (__res >= __len)
 	{
-	  // Try to increment size of translated string.
-	  size_t __len2 = __len * 2;
-	  _CharT* __c2 = static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT) * __len2));
-	  __res = _M_transform_helper(__c2, __lo, __len);
-	  // XXX Throw exception if still indeterminate?
+	  _CharT* __c2 =
+	    static_cast<_CharT*>(__builtin_alloca(sizeof(_CharT) * (__res + 1)));
+	  size_t __res2 = _M_transform_helper(__c2, __lo, __res + 1);
+	  return string_type(__c2);
 	}
       return string_type(__c);
     }