1 files changed, 78 insertions, 0 deletions
diff --git a/modules/mahonia/gbk.go b/modules/mahonia/gbk.go
new file mode 100644
index 0000000000..ffb13b286e
--- /dev/null
+++ b/modules/mahonia/gbk.go
@@ -0,0 +1,78 @@
+package mahonia
+
+// Converters for GBK encoding.
+
+func init() {
+	RegisterCharset(&Charset{
+		Name:    "GBK",
+		Aliases: []string{"GB2312"}, // GBK is a superset of GB2312.
+		NewDecoder: func() Decoder {
+			return decodeGBKRune
+		},
+		NewEncoder: func() Encoder {
+			return encodeGBKRune
+		},
+	})
+}
+
+func decodeGBKRune(p []byte) (r rune, size int, status Status) {
+	if len(p) == 0 {
+		status = NO_ROOM
+		return
+	}
+
+	b := p[0]
+	if b < 128 {
+		return rune(b), 1, SUCCESS
+	}
+
+	if len(p) < 2 {
+		status = NO_ROOM
+		return
+	}
+
+	c := uint16(p[0])<<8 + uint16(p[1])
+	r = rune(gbkToUnicode[c])
+	if r == 0 {
+		r = gbkToUnicodeExtra[c]
+	}
+
+	if r != 0 {
+		return r, 2, SUCCESS
+	}
+
+	return 0xfffd, 1, INVALID_CHAR
+}
+
+func encodeGBKRune(p []byte, r rune) (size int, status Status) {
+	if len(p) == 0 {
+		status = NO_ROOM
+		return
+	}
+
+	if r < 128 {
+		p[0] = byte(r)
+		return 1, SUCCESS
+	}
+
+	if len(p) < 2 {
+		status = NO_ROOM
+		return
+	}
+
+	var c uint16
+	if r < 0x10000 {
+		c = unicodeToGBK[r]
+	} else {
+		c = unicodeToGBKExtra[r]
+	}
+
+	if c != 0 {
+		p[0] = byte(c >> 8)
+		p[1] = byte(c)
+		return 2, SUCCESS
+	}
+
+	p[0] = 0x1a
+	return 1, INVALID_CHAR
+}