diff options
Diffstat (limited to 'libgo/go/strings/reader.go')
| -rw-r--r-- | libgo/go/strings/reader.go | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/libgo/go/strings/reader.go b/libgo/go/strings/reader.go index 6c1a506..eb2fa11 100644 --- a/libgo/go/strings/reader.go +++ b/libgo/go/strings/reader.go @@ -13,6 +13,7 @@ import ( // A Reader implements the io.Reader, io.ReaderAt, io.Seeker, io.WriterTo, // io.ByteScanner, and io.RuneScanner interfaces by reading // from a string. +// The zero value for Reader operates like a Reader of an empty string. type Reader struct { s string i int64 // current reading index @@ -70,10 +71,10 @@ func (r *Reader) ReadByte() (byte, error) { } func (r *Reader) UnreadByte() error { - r.prevRune = -1 if r.i <= 0 { return errors.New("strings.Reader.UnreadByte: at beginning of string") } + r.prevRune = -1 r.i-- return nil } @@ -94,6 +95,9 @@ func (r *Reader) ReadRune() (ch rune, size int, err error) { } func (r *Reader) UnreadRune() error { + if r.i <= 0 { + return errors.New("strings.Reader.UnreadRune: at beginning of string") + } if r.prevRune < 0 { return errors.New("strings.Reader.UnreadRune: previous operation was not ReadRune") } |