1 files changed, 98 insertions, 0 deletions
diff --git a/lib/unistr/u8-mblen.c b/lib/unistr/u8-mblen.c
new file mode 100644
index 00000000..1981befe
--- /dev/null
+++ b/lib/unistr/u8-mblen.c
@@ -0,0 +1,98 @@
+/* Look at first character in UTF-8 string.
+   Copyright (C) 1999-2000, 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"
+
+int
+u8_mblen (const uint8_t *s, size_t n)
+{
+  if (n > 0)
+    {
+      /* Keep in sync with unistr.h and utf8-ucs4.c.  */
+      uint8_t c = *s;
+
+      if (c < 0x80)
+	return (c != 0 ? 1 : 0);
+      if (c >= 0xc2)
+	{
+	  if (c < 0xe0)
+	    {
+	      if (n >= 2
+#if CONFIG_UNICODE_SAFETY
+		  && (s[1] ^ 0x80) < 0x40
+#endif
+		 )
+		return 2;
+	    }
+	  else if (c < 0xf0)
+	    {
+	      if (n >= 3
+#if CONFIG_UNICODE_SAFETY
+		  && (s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
+		  && (c >= 0xe1 || s[1] >= 0xa0)
+		  && (c != 0xed || s[1] < 0xa0)
+#endif
+		 )
+		return 3;
+	    }
+	  else if (c < 0xf8)
+	    {
+	      if (n >= 4
+#if CONFIG_UNICODE_SAFETY
+		  && (s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
+		  && (s[3] ^ 0x80) < 0x40
+		  && (c >= 0xf1 || s[1] >= 0x90)
+#if 1
+		  && (c < 0xf4 || (c == 0xf4 && s[1] < 0x90))
+#endif
+#endif
+		 )
+		return 4;
+	    }
+#if 0
+	  else if (c < 0xfc)
+	    {
+	      if (n >= 5
+#if CONFIG_UNICODE_SAFETY
+		  && (s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
+		  && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
+		  && (c >= 0xf9 || s[1] >= 0x88)
+#endif
+		 )
+		return 5;
+	    }
+	  else if (c < 0xfe)
+	    {
+	      if (n >= 6
+#if CONFIG_UNICODE_SAFETY
+		  && (s[1] ^ 0x80) < 0x40 && (s[2] ^ 0x80) < 0x40
+		  && (s[3] ^ 0x80) < 0x40 && (s[4] ^ 0x80) < 0x40
+		  && (s[5] ^ 0x80) < 0x40
+		  && (c >= 0xfd || s[1] >= 0x84)
+#endif
+		 )
+		return 6;
+	    }
+#endif
+	}
+    }
+  /* invalid or incomplete multibyte character */
+  return -1;
+}