libgo: Update to weekly.2012-01-15.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@183539 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 5 insertions, 3 deletions

diff --git a/libgo/go/bytes/buffer.go b/libgo/go/bytes/buffer.go
index e66ac026e5b..77757af1d80 100644
--- a/libgo/go/bytes/buffer.go
+++ b/libgo/go/bytes/buffer.go
@@ -97,8 +97,7 @@ func (b *Buffer) grow(n int) int {
 func (b *Buffer) Write(p []byte) (n int, err error) {
 	b.lastRead = opInvalid
 	m := b.grow(len(p))
-	copy(b.buf[m:], p)
-	return len(p), nil
+	return copy(b.buf[m:], p), nil
 }
 
 // WriteString appends the contents of s to the buffer.  The return
@@ -200,13 +199,16 @@ func (b *Buffer) WriteRune(r rune) (n int, err error) {
 
 // Read reads the next len(p) bytes from the buffer or until the buffer
 // is drained.  The return value n is the number of bytes read.  If the
-// buffer has no data to return, err is io.EOF even if len(p) is zero;
+// buffer has no data to return, err is io.EOF (unless len(p) is zero);
 // otherwise it is nil.
 func (b *Buffer) Read(p []byte) (n int, err error) {
 	b.lastRead = opInvalid
 	if b.off >= len(b.buf) {
 		// Buffer is empty, reset to recover space.
 		b.Truncate(0)
+		if len(p) == 0 {
+			return
+		}
 		return 0, io.EOF
 	}
 	n = copy(p, b.buf[b.off:])