1 files changed, 75 insertions, 0 deletions
diff --git a/include/linux/utf.h b/include/linux/utf.h
new file mode 100644
index 0000000000..e1f7d3bd1d
--- /dev/null
+++ b/include/linux/utf.h
@@ -0,0 +1,75 @@
+#ifndef _LINUX_UTF_H
+#define _LINUX_UTF_H
+
+#include <asm/unaligned.h>
+
+static inline int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len)
+{
+	int	count = 0;
+	u8	c;
+	u16	uchar;
+
+	/*
+	 * this insists on correct encodings, though not minimal ones.
+	 * BUT it currently rejects legit 4-byte UTF-8 code points,
+	 * which need surrogate pairs.  (Unicode 3.1 can use them.)
+	 */
+	while (len != 0 && (c = (u8) *s++) != 0) {
+		if ((c & 0x80)) {
+			/*
+			 * 2-byte sequence:
+			 * 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
+			 */
+			if ((c & 0xe0) == 0xc0) {
+				uchar = (c & 0x1f) << 6;
+
+				c = (u8) *s++;
+				if ((c & 0xc0) != 0x80)
+					goto fail;
+				c &= 0x3f;
+				uchar |= c;
+
+			/*
+			 * 3-byte sequence (most CJKV characters):
+			 * zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
+			 */
+			} else if ((c & 0xf0) == 0xe0) {
+				uchar = (c & 0x0f) << 12;
+
+				c = (u8) *s++;
+				if ((c & 0xc0) != 0x80)
+					goto fail;
+				c &= 0x3f;
+				uchar |= c << 6;
+
+				c = (u8) *s++;
+				if ((c & 0xc0) != 0x80)
+					goto fail;
+				c &= 0x3f;
+				uchar |= c;
+
+				/* no bogus surrogates */
+				if (0xd800 <= uchar && uchar <= 0xdfff)
+					goto fail;
+
+			/*
+			 * 4-byte sequence (surrogate pairs, currently rare):
+			 * 11101110wwwwzzzzyy + 110111yyyyxxxxxx
+			 *     = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx
+			 * (uuuuu = wwww + 1)
+			 * FIXME accept the surrogate code points (only)
+			 */
+			} else
+				goto fail;
+		} else
+			uchar = c;
+		put_unaligned_le16(uchar, cp++);
+		count++;
+		len--;
+	}
+	return count;
+fail:
+	return -1;
+}
+
+#endif /* _LINUX_UTF_H */