1 files changed, 22 insertions, 30 deletions
diff --git a/libgo/go/encoding/base32/base32.go b/libgo/go/encoding/base32/base32.go
index 3fb6cac..e14d2d4 100644
--- a/libgo/go/encoding/base32/base32.go
+++ b/libgo/go/encoding/base32/base32.go
@@ -284,7 +284,12 @@ func (e CorruptInputError) Error() string {
 // additional data is an error. This method assumes that src has been
 // stripped of all supported whitespace ('\r' and '\n').
 func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
+	// Lift the nil check outside of the loop.
+	_ = enc.decodeMap
+
+	dsti := 0
 	olen := len(src)
+
 	for len(src) > 0 && !end {
 		// Decode quantum using the base32 alphabet
 		var dbuf [8]byte
@@ -292,17 +297,15 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 
 		for j := 0; j < 8; {
 
-			// We have reached the end and are missing padding
-			if len(src) == 0 && enc.padChar != NoPadding {
-				return n, false, CorruptInputError(olen - len(src) - j)
-			}
-
-			// We have reached the end and are not expecing any padding
-			if len(src) == 0 && enc.padChar == NoPadding {
+			if len(src) == 0 {
+				if enc.padChar != NoPadding {
+					// We have reached the end and are missing padding
+					return n, false, CorruptInputError(olen - len(src) - j)
+				}
+				// We have reached the end and are not expecing any padding
 				dlen, end = j, true
 				break
 			}
-
 			in := src[0]
 			src = src[1:]
 			if in == byte(enc.padChar) && j >= 2 && len(src) < 8 {
@@ -339,37 +342,26 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		// quantum
 		switch dlen {
 		case 8:
-			dst[4] = dbuf[6]<<5 | dbuf[7]
+			dst[dsti+4] = dbuf[6]<<5 | dbuf[7]
+			n++
 			fallthrough
 		case 7:
-			dst[3] = dbuf[4]<<7 | dbuf[5]<<2 | dbuf[6]>>3
+			dst[dsti+3] = dbuf[4]<<7 | dbuf[5]<<2 | dbuf[6]>>3
+			n++
 			fallthrough
 		case 5:
-			dst[2] = dbuf[3]<<4 | dbuf[4]>>1
+			dst[dsti+2] = dbuf[3]<<4 | dbuf[4]>>1
+			n++
 			fallthrough
 		case 4:
-			dst[1] = dbuf[1]<<6 | dbuf[2]<<1 | dbuf[3]>>4
+			dst[dsti+1] = dbuf[1]<<6 | dbuf[2]<<1 | dbuf[3]>>4
+			n++
 			fallthrough
 		case 2:
-			dst[0] = dbuf[0]<<3 | dbuf[1]>>2
-		}
-
-		if !end {
-			dst = dst[5:]
-		}
-
-		switch dlen {
-		case 2:
-			n += 1
-		case 4:
-			n += 2
-		case 5:
-			n += 3
-		case 7:
-			n += 4
-		case 8:
-			n += 5
+			dst[dsti+0] = dbuf[0]<<3 | dbuf[1]>>2
+			n++
 		}
+		dsti += 5
 	}
 	return n, end, nil
 }