1 files changed, 24 insertions, 7 deletions

diff --git a/libgo/go/bytes/bytes.go b/libgo/go/bytes/bytes.go
index e3ee5b1..e42f744 100644
--- a/libgo/go/bytes/bytes.go
+++ b/libgo/go/bytes/bytes.go
@@ -37,10 +37,6 @@ func Compare(a, b []byte) int {
 	return 0
 }
 
-// Equal returns a boolean reporting whether a == b.
-// A nil argument is equivalent to an empty slice.
-func Equal(a, b []byte) bool
-
 func equalPortable(a, b []byte) bool {
 	if len(a) != len(b) {
 		return false
@@ -465,10 +461,10 @@ func isSeparator(r rune) bool {
 	return unicode.IsSpace(r)
 }
 
-// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
-
 // Title returns a copy of s with all Unicode letters that begin words
 // mapped to their title case.
+//
+// BUG: The rule Title uses for word boundaries does not handle Unicode punctuation properly.
 func Title(s []byte) []byte {
 	// Use a closure here to remember state.
 	// Hackish but effective. Depends on Map scanning in order and calling
@@ -515,6 +511,24 @@ func TrimFunc(s []byte, f func(r rune) bool) []byte {
 	return TrimRightFunc(TrimLeftFunc(s, f), f)
 }
 
+// TrimPrefix returns s without the provided leading prefix string.
+// If s doesn't start with prefix, s is returned unchanged.
+func TrimPrefix(s, prefix []byte) []byte {
+	if HasPrefix(s, prefix) {
+		return s[len(prefix):]
+	}
+	return s
+}
+
+// TrimSuffix returns s without the provided trailing suffix string.
+// If s doesn't end with suffix, s is returned unchanged.
+func TrimSuffix(s, suffix []byte) []byte {
+	if HasSuffix(s, suffix) {
+		return s[:len(s)-len(suffix)]
+	}
+	return s
+}
+
 // IndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
 // It returns the byte index in s of the first Unicode
 // code point satisfying f(c), or -1 if none do.
@@ -553,7 +567,10 @@ func indexFunc(s []byte, f func(r rune) bool, truth bool) int {
 // inverted.
 func lastIndexFunc(s []byte, f func(r rune) bool, truth bool) int {
 	for i := len(s); i > 0; {
-		r, size := utf8.DecodeLastRune(s[0:i])
+		r, size := rune(s[i-1]), 1
+		if r >= utf8.RuneSelf {
+			r, size = utf8.DecodeLastRune(s[0:i])
+		}
 		i -= size
 		if f(r) == truth {
 			return i