codecvt_members.cc (do_out): If we can upper bound the total number of external…

codecvt_members.cc (do_out): If we can upper bound the total number of external chars to something smaller...

2003-11-19  Paolo Carlini  <pcarlini@suse.de>

	* config/locale/gnu/codecvt_members.cc (do_out): If
	we can upper bound the total number of external chars
	to something smaller than __to_end - __to, avoid the
	temporary buffer, the memcopy and simplify the loop.
	* config/locale/generic/codecvt_members.cc (do_out):
	Likewise.

From-SVN: r73733

libstdc++-v3/ChangeLog

+2003-11-19  Paolo Carlini  <pcarlini@suse.de>
+
+	* config/locale/gnu/codecvt_members.cc (do_out): If
+	we can upper bound the total number of external chars
+	to something smaller than __to_end - __to, avoid the
+	temporary buffer, the memcopy and simplify the loop.
+	* config/locale/generic/codecvt_members.cc (do_out):
+	Likewise.
+
 2003-11-19  Andreas Tobler  <a.tobler@schweiz.ch>
 
 	* testsuite/lib/libstdc++.exp: Add DYLD_LIBRARY_PATH for darwin.

libstdc++-v3/config/locale/generic/codecvt_members.cc

@@ -49,17 +49,35 @@ namespace std
     result __ret = ok;
     // The conversion must be done using a temporary destination buffer
     // since it is not possible to pass the size of the buffer to wcrtomb
-    extern_type __buf[MB_LEN_MAX];
-    // A temporary state must be used since the result of the last
-    // conversion may be thrown away.
     state_type __tmp_state(__state);
 
     // The conversion must be done by calling wcrtomb in a loop rather
     // than using wcsrtombs because wcsrtombs assumes that the input is
     // zero-terminated.
+
+    // Either we can upper bound the total number of external characters to
+    // something smaller than __to_end - __to or the conversion must be done
+    // using a temporary destination buffer since it is not possible to
+    // pass the size of the buffer to wcrtomb
+    if (MB_CUR_MAX * (__from_end - __from) - (__to_end - __to) <= 0)
+      while (__from < __from_end)
+	{
+	  const size_t __conv = wcrtomb(__to, *__from, &__tmp_state);
+	  if (__conv == static_cast<size_t>(-1))
+	    {
+	      __ret = error;
+	      break;
+	    }
+	  __state = __tmp_state;
+	  __to += __conv;
+	  __from++;
+	}
+    else
+      {
+	extern_type __buf[MB_LEN_MAX];
 	while (__from < __from_end && __to < __to_end)
 	  {
-	size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
+	    const size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
 	    if (__conv == static_cast<size_t>(-1))
 	      {
 		__ret = error;
@@ -76,6 +94,7 @@ namespace std
 	    __to += __conv;
 	    __from++;
 	  }
+      }
 
     if (__ret == ok && __from < __from_end)
       __ret = partial;

libstdc++-v3/config/locale/gnu/codecvt_members.cc

@@ -48,9 +48,6 @@ namespace std
 	 extern_type*& __to_next) const
   {
     result __ret = ok;
-    // The conversion must be done using a temporary destination buffer
-    // since it is not possible to pass the size of the buffer to wcrtomb
-    extern_type __buf[MB_LEN_MAX];
     // A temporary state must be used since the result of the last
     // conversion may be thrown away.
     state_type __tmp_state(__state);   
@@ -62,9 +59,30 @@ namespace std
     // The conversion must be done by calling wcrtomb in a loop rather
     // than using wcsrtombs because wcsrtombs assumes that the input is
     // zero-terminated.
+
+    // Either we can upper bound the total number of external characters to
+    // something smaller than __to_end - __to or the conversion must be done
+    // using a temporary destination buffer since it is not possible to
+    // pass the size of the buffer to wcrtomb
+    if (MB_CUR_MAX * (__from_end - __from) - (__to_end - __to) <= 0)
+      while (__from < __from_end)
+	{
+	  const size_t __conv = wcrtomb(__to, *__from, &__tmp_state);
+	  if (__conv == static_cast<size_t>(-1))
+	    {
+	      __ret = error;
+	      break;
+	    }
+	  __state = __tmp_state;
+	  __to += __conv;
+	  __from++;
+	}
+    else
+      {
+	extern_type __buf[MB_LEN_MAX];
 	while (__from < __from_end && __to < __to_end)
 	  {
-	size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
+	    const size_t __conv = wcrtomb(__buf, *__from, &__tmp_state);
 	    if (__conv == static_cast<size_t>(-1))
 	      {
 		__ret = error;
@@ -81,6 +99,7 @@ namespace std
 	    __to += __conv;
 	    __from++;
 	  }
+      }
 
 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2)
     __uselocale(__old);