bytes: fix UnreadByte failure after ReadBytes
Fixes #4583.
R=golang-dev, minux.ma, bradfitz, rsc, dave
CC=golang-dev
https://golang.org/cl/6976050
diff --git a/src/pkg/bytes/buffer.go b/src/pkg/bytes/buffer.go
index 3ae9303..85c1577 100644
--- a/src/pkg/bytes/buffer.go
+++ b/src/pkg/bytes/buffer.go
@@ -367,7 +367,7 @@
return
}
-// readSlice is like readBytes but returns a reference to internal buffer data.
+// readSlice is like ReadBytes but returns a reference to internal buffer data.
func (b *Buffer) readSlice(delim byte) (line []byte, err error) {
i := IndexByte(b.buf[b.off:], delim)
end := b.off + i + 1
@@ -377,6 +377,7 @@
}
line = b.buf[b.off:end]
b.off = end
+ b.lastRead = opRead
return line, err
}
diff --git a/src/pkg/bytes/buffer_test.go b/src/pkg/bytes/buffer_test.go
index 69b2507..f9fb262 100644
--- a/src/pkg/bytes/buffer_test.go
+++ b/src/pkg/bytes/buffer_test.go
@@ -453,3 +453,25 @@
t.Errorf("wrong count; got %d want 0", n)
}
}
+
+func TestUnreadByte(t *testing.T) {
+ b := new(Buffer)
+ b.WriteString("abcdefghijklmnopqrstuvwxyz")
+
+ _, err := b.ReadBytes('m')
+ if err != nil {
+ t.Fatalf("ReadBytes: %v", err)
+ }
+
+ err = b.UnreadByte()
+ if err != nil {
+ t.Fatalf("UnreadByte: %v", err)
+ }
+ c, err := b.ReadByte()
+ if err != nil {
+ t.Fatalf("ReadByte: %v", err)
+ }
+ if c != 'm' {
+ t.Errorf("ReadByte = %q; want %q", c, 'm')
+ }
+}
