1 files changed, 50 insertions, 0 deletions
diff --git a/modules/mahonia/translate.go b/modules/mahonia/translate.go
new file mode 100644
index 00000000..ea415844
--- /dev/null
+++ b/modules/mahonia/translate.go
@@ -0,0 +1,50 @@
+package mahonia
+
+import "unicode/utf8"
+
+// Translate enables a Decoder to implement go-charset's Translator interface.
+func (d Decoder) Translate(data []byte, eof bool) (n int, cdata []byte, err error) {
+	cdata = make([]byte, len(data)+1)
+	destPos := 0
+
+	for n < len(data) {
+		rune, size, status := d(data[n:])
+
+		switch status {
+		case STATE_ONLY:
+			n += size
+			continue
+
+		case NO_ROOM:
+			if !eof {
+				return n, cdata[:destPos], nil
+			}
+			rune = 0xfffd
+			n = len(data)
+
+		default:
+			n += size
+		}
+
+		if rune < 128 {
+			if destPos >= len(cdata) {
+				cdata = doubleLength(cdata)
+			}
+			cdata[destPos] = byte(rune)
+			destPos++
+		} else {
+			if destPos+utf8.RuneLen(rune) > len(cdata) {
+				cdata = doubleLength(cdata)
+			}
+			destPos += utf8.EncodeRune(cdata[destPos:], rune)
+		}
+	}
+
+	return n, cdata[:destPos], nil
+}
+
+func doubleLength(b []byte) []byte {
+	b2 := make([]byte, 2*len(b))
+	copy(b2, b)
+	return b2
+}