1 files changed, 108 insertions, 0 deletions
diff --git a/lib/memxfrm.c b/lib/memxfrm.c
new file mode 100644
index 000000000..79db94b8f
--- /dev/null
+++ b/lib/memxfrm.c
@@ -0,0 +1,108 @@
+/* Locale-specific memory transformation
+
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+/* Written by Paul Eggert <eggert@cs.ucla.edu>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "memxfrm.h"
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Store into DEST (of size DESTSIZE) the text in SRC (of size SRCSIZE)
+   transformed so that the result of memcmp on two transformed texts
+   (with ties going to the longer text) is the same as the result of
+   memcoll on the two texts before their transformation.  Perhaps
+   temporarily modify the byte after SRC, but restore its original
+   contents before returning.
+
+   Return the size of the resulting text, or an indeterminate value if
+   there is an error.  Set errno to an error number if there is an
+   error, and to zero otherwise.  DEST contains an indeterminate value
+   if there is an error or if the resulting size is greater than
+   DESTSIZE.  */
+
+size_t
+memxfrm (char *restrict dest, size_t destsize,
+	 char *restrict src, size_t srcsize)
+{
+#if HAVE_STRXFRM
+
+  size_t di = 0;
+  size_t si = 0;
+  size_t result = 0;
+
+  char ch = src[srcsize];
+  src[srcsize] = '\0';
+
+  while (si < srcsize)
+    {
+      size_t slen = strlen (src + si);
+
+      size_t result0 = result;
+      errno = 0;
+      result += strxfrm (dest + di, src + si, destsize - di) + 1;
+      if (errno != 0)
+	break;
+      if (result <= result0)
+	{
+	  errno = ERANGE;
+	  break;
+	}
+
+      if (result == destsize + 1 && si + slen == srcsize)
+	{
+	  /* The destination is exactly the right size, but strxfrm wants
+	     room for a trailing null.  Work around the problem with a
+	     temporary buffer.  */
+	  size_t bufsize = destsize - di + 1;
+	  char stackbuf[4000];
+	  char *buf = stackbuf;
+	  if (sizeof stackbuf < bufsize)
+	    {
+	      buf = malloc (bufsize);
+	      if (! buf)
+		break;
+	    }
+	  strxfrm (buf, src + si, bufsize);
+	  memcpy (dest + di, buf, destsize - di);
+	  if (sizeof stackbuf < bufsize)
+	    free (buf);
+	  errno = 0;
+	}
+
+      di = (result < destsize ? result : destsize);
+      si += slen + 1;
+    }
+
+  src[srcsize] = ch;
+  return result - (si != srcsize);
+
+#else
+
+  if (srcsize < destsize)
+    memcpy (dest, src, srcsize);
+  errno = 0;
+  return srcsize;
+
+#endif
+}