New module 'wcsstr'.

* modules/wcsstr: New file.
* lib/wchar.in.h (wcsstr): New declaration.
* lib/wcsstr.c: New file.
* lib/wcsstr-impl.h: New file, from libutf8 with modifications.
* m4/wcsstr.m4: New file.
* m4/wchar_h.m4 (gl_WCHAR_H): Test whether wcsstr is declared.
(gl_WCHAR_H_DEFAULTS): Initialize GNULIB_WCSSTR, HAVE_WCSSTR.
* modules/wchar (Makefile.am): Substitute GNULIB_WCSSTR, HAVE_WCSSTR.
* tests/test-wchar-c++.cc: Test the declaration of wcsstr.
* doc/posix-functions/wcsstr.texi: Mention the new module.

1 files changed, 51 insertions, 0 deletions

diff --git a/lib/wcsstr-impl.h b/lib/wcsstr-impl.h
new file mode 100644
index 0000000000..f3fb3fb967
--- /dev/null
+++ b/lib/wcsstr-impl.h
@@ -0,0 +1,51 @@
+/* Locate a substring in a wide string.
+   Copyright (C) 1999, 2011 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 1999.
+
+   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 3 of the License, 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, see <http://www.gnu.org/licenses/>.  */
+
+wchar_t *
+wcsstr (const wchar_t *haystack, const wchar_t *needle)
+{
+  wchar_t n = needle[0];
+
+  /* Is needle empty?  */
+  if (n == (wchar_t)'\0')
+    return (wchar_t *) haystack;
+
+  /* Is needle nearly empty?  */
+  if (needle[1] == (wchar_t)'\0')
+    return wcschr (haystack, n);
+
+  /* Search for needle's first character.  */
+  for (; *haystack != (wchar_t)'\0'; haystack++)
+    {
+      if (*haystack == n)
+        {
+          /* Compare with needle's remaining characters.  */
+          const wchar_t *hptr = haystack + 1;
+          const wchar_t *nptr = needle + 1;
+          for (;;)
+            {
+              if (*hptr != *nptr)
+                break;
+              hptr++; nptr++;
+              if (*nptr == (wchar_t)'\0')
+                return (wchar_t *) haystack;
+            }
+        }
+    }
+
+  return NULL;
+}