1 files changed, 39 insertions, 0 deletions
diff --git a/lib/unistr/u32-prev.c b/lib/unistr/u32-prev.c
new file mode 100644
index 00000000..bc20c93f
--- /dev/null
+++ b/lib/unistr/u32-prev.c
@@ -0,0 +1,39 @@
+/* Iterate over previous character in UTF-32 string.
+   Copyright (C) 2002, 2006-2007 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2002.
+
+   This program is free software: you can redistribute it and/or modify it
+   under the terms of the GNU Lesser 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include "unistr.h"
+
+const uint32_t *
+u32_prev (ucs4_t *puc, const uint32_t *s, const uint32_t *start)
+{
+  if (s != start)
+    {
+      uint32_t c_1 = s[-1];
+
+#if CONFIG_UNICODE_SAFETY
+      if (c_1 < 0xd800 || (c_1 >= 0xe000 && c_1 < 0x110000))
+#endif
+	{
+	  *puc = c_1;
+	  return s - 1;
+	}
+    }
+  return NULL;
+}