1 files changed, 84 insertions, 0 deletions
diff --git a/stdlib/mbtowc.c b/stdlib/mbtowc.c
new file mode 100644
index 0000000000..62103407c0
--- /dev/null
+++ b/stdlib/mbtowc.c
@@ -0,0 +1,84 @@
+/* Copyright (C) 1991, 1992, 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <localeinfo.h>
+#include <ctype.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+long int _mb_shift = 0;
+
+/* Convert the multibyte character at S, which is no longer
+   than N characters, to its `wchar_t' representation, placing
+   this n *PWC and returning its length.  */
+int
+DEFUN(mbtowc, (pwc, s, n), wchar_t *pwc AND CONST char *s AND size_t n)
+{
+  register CONST mb_char *mb;
+  register wchar_t i;
+
+  if (s == NULL)
+    return _mb_shift != 0;
+
+  if (*s == '\0')
+    /* ANSI 4.10.7.2, line 19.  */
+    return 0;
+
+  if (isascii (*s))
+    {
+      /* A normal ASCII character translates to itself.  */
+      if (pwc != NULL)
+	*pwc = (wchar_t) *s;
+      return 1;
+    }
+
+  if (_ctype_info->mbchar == NULL ||
+      _ctype_info->mbchar->mb_chars == NULL)
+    return -1;
+
+  if (n > MB_CUR_MAX)
+    n = MB_CUR_MAX;
+
+  for (i = 0; i < WCHAR_MAX; ++i)
+    {
+      mb = &_ctype_info->mbchar->mb_chars[i];
+      /* EOF and NUL aren't MB chars.  */
+      if (i == (wchar_t) EOF || i == (wchar_t) '\0')
+	continue;
+      /* Normal ASCII values can't start MB chars.  */
+      else if (isascii(i))
+	continue;
+      else if (mb->string == NULL || mb->len == 0)
+	continue;
+      else if (mb->len > n)
+	continue;
+      else if (!strncmp(mb->string, s, mb->len))
+	{
+	  _mb_shift += mb->shift;
+	  if (pwc != NULL)
+	    *pwc = i;
+	  return mb->len;
+	}
+    }
+
+  return -1;
+}