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[thirdparty/glibc.git] / stdlib / mblen.c

diff --git a/stdlib/mblen.c b/stdlib/mblen.c
index 120551c9a249d7031207072d3f34b31d628a9918..9a49bc5d0d245e6658eb87c893004a88b46b5771 100644 (file)
--- a/stdlib/mblen.c
+++ b/stdlib/mblen.c
@@ -1,30 +1,68 @@
-/* Copyright (C) 1991, 1997 Free Software Foundation, Inc.
+/* Copyright (C) 1991-2019 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.
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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.
+   Lesser 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., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
 
 #include <stdlib.h>
+#include <string.h>
+#include <wchar.h>
+#include <gconv.h>
+#include <wcsmbs/wcsmbsload.h>
 
-#undef mblen
 
+/* Internal state.  */
+static mbstate_t state;
 
 /* Return the length of the multibyte character (if there is one)
-   at S which is no longer than N characters.  */
+   at S which is no longer than N characters.
+   The ISO C standard says that the `mblen' function must not change
+   the state of the `mbtowc' function.  */
 int
 mblen (const char *s, size_t n)
 {
-  return mbtowc ((wchar_t *) NULL, s, n);
+  int result;
+
+  /* If S is NULL the function has to return null or not null
+     depending on the encoding having a state depending encoding or
+     not.  */
+  if (s == NULL)
+    {
+      const struct gconv_fcts *fcts;
+
+      /* Get the conversion functions.  */
+      fcts = get_gconv_fcts (_NL_CURRENT_DATA (LC_CTYPE));
+
+      /* Reset the state.  */
+      memset (&state, '\0', sizeof state);
+
+      result = fcts->towc->__stateful;
+    }
+  else if (*s == '\0')
+    /* According to the ISO C 89 standard this is the expected behaviour.  */
+    result = 0;
+  else
+    {
+      memset (&state, '\0', sizeof state);
+
+      result = __mbrtowc (NULL, s, n, &state);
+
+      /* The `mbrtowc' functions tell us more than we need.  Fold the -1
+        and -2 result into -1.  */
+      if (result < 0)
+       result = -1;
+    }
+
+  return result;
 }