зеркало из https://github.com/golang/snappy.git
snappy: add Reset methods to Reader and Writer.
LGTM=bradfitz R=bradfitz CC=golang-codereviews https://codereview.appspot.com/202990043
This commit is contained in:
Родитель
4c08685702
Коммит
eaed4addcd
|
@ -131,15 +131,16 @@ func Decode(dst, src []byte) ([]byte, error) {
|
|||
// NewReader returns a new Reader that decompresses from r, using the framing
|
||||
// format described at
|
||||
// https://code.google.com/p/snappy/source/browse/trunk/framing_format.txt
|
||||
func NewReader(r io.Reader) io.Reader {
|
||||
return &reader{
|
||||
func NewReader(r io.Reader) *Reader {
|
||||
return &Reader{
|
||||
r: r,
|
||||
decoded: make([]byte, maxUncompressedChunkLen),
|
||||
buf: make([]byte, MaxEncodedLen(maxUncompressedChunkLen)+checksumSize),
|
||||
}
|
||||
}
|
||||
|
||||
type reader struct {
|
||||
// Reader is an io.Reader than can read Snappy-compressed bytes.
|
||||
type Reader struct {
|
||||
r io.Reader
|
||||
err error
|
||||
decoded []byte
|
||||
|
@ -149,7 +150,18 @@ type reader struct {
|
|||
readHeader bool
|
||||
}
|
||||
|
||||
func (r *reader) readFull(p []byte) (ok bool) {
|
||||
// Reset discards any buffered data, resets all state, and switches the Snappy
|
||||
// reader to read from r. This permits reusing a Reader rather than allocating
|
||||
// a new one.
|
||||
func (r *Reader) Reset(reader io.Reader) {
|
||||
r.r = reader
|
||||
r.err = nil
|
||||
r.i = 0
|
||||
r.j = 0
|
||||
r.readHeader = false
|
||||
}
|
||||
|
||||
func (r *Reader) readFull(p []byte) (ok bool) {
|
||||
if _, r.err = io.ReadFull(r.r, p); r.err != nil {
|
||||
if r.err == io.ErrUnexpectedEOF {
|
||||
r.err = ErrCorrupt
|
||||
|
@ -159,7 +171,8 @@ func (r *reader) readFull(p []byte) (ok bool) {
|
|||
return true
|
||||
}
|
||||
|
||||
func (r *reader) Read(p []byte) (int, error) {
|
||||
// Read satisfies the io.Reader interface.
|
||||
func (r *Reader) Read(p []byte) (int, error) {
|
||||
if r.err != nil {
|
||||
return 0, r.err
|
||||
}
|
||||
|
|
|
@ -177,14 +177,15 @@ func MaxEncodedLen(srcLen int) int {
|
|||
// NewWriter returns a new Writer that compresses to w, using the framing
|
||||
// format described at
|
||||
// https://code.google.com/p/snappy/source/browse/trunk/framing_format.txt
|
||||
func NewWriter(w io.Writer) io.Writer {
|
||||
return &writer{
|
||||
func NewWriter(w io.Writer) *Writer {
|
||||
return &Writer{
|
||||
w: w,
|
||||
enc: make([]byte, MaxEncodedLen(maxUncompressedChunkLen)),
|
||||
}
|
||||
}
|
||||
|
||||
type writer struct {
|
||||
// Writer is an io.Writer than can write Snappy-compressed bytes.
|
||||
type Writer struct {
|
||||
w io.Writer
|
||||
err error
|
||||
enc []byte
|
||||
|
@ -192,7 +193,16 @@ type writer struct {
|
|||
wroteHeader bool
|
||||
}
|
||||
|
||||
func (w *writer) Write(p []byte) (n int, errRet error) {
|
||||
// Reset discards the writer's state and switches the Snappy writer to write to
|
||||
// w. This permits reusing a Writer rather than allocating a new one.
|
||||
func (w *Writer) Reset(writer io.Writer) {
|
||||
w.w = writer
|
||||
w.err = nil
|
||||
w.wroteHeader = false
|
||||
}
|
||||
|
||||
// Write satisfies the io.Writer interface.
|
||||
func (w *Writer) Write(p []byte) (n int, errRet error) {
|
||||
if w.err != nil {
|
||||
return 0, w.err
|
||||
}
|
||||
|
|
|
@ -79,8 +79,19 @@ func TestSmallRegular(t *testing.T) {
|
|||
}
|
||||
}
|
||||
|
||||
func cmp(a, b []byte) error {
|
||||
if len(a) != len(b) {
|
||||
return fmt.Errorf("got %d bytes, want %d", len(a), len(b))
|
||||
}
|
||||
for i := range a {
|
||||
if a[i] != b[i] {
|
||||
return fmt.Errorf("byte #%d: got 0x%02x, want 0x%02x", i, a[i], b[i])
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func TestFramingFormat(t *testing.T) {
|
||||
loop:
|
||||
for _, tf := range testFiles {
|
||||
if err := downloadTestdata(tf.filename); err != nil {
|
||||
t.Fatalf("failed to download testdata: %s", err)
|
||||
|
@ -96,17 +107,80 @@ loop:
|
|||
t.Errorf("%s: decoding: %v", tf.filename, err)
|
||||
continue
|
||||
}
|
||||
if !bytes.Equal(dst, src) {
|
||||
if len(dst) != len(src) {
|
||||
t.Errorf("%s: got %d bytes, want %d", tf.filename, len(dst), len(src))
|
||||
if err := cmp(dst, src); err != nil {
|
||||
t.Errorf("%s: %v", tf.filename, err)
|
||||
continue
|
||||
}
|
||||
for i := range dst {
|
||||
if dst[i] != src[i] {
|
||||
t.Errorf("%s: byte #%d: got 0x%02x, want 0x%02x", tf.filename, i, dst[i], src[i])
|
||||
continue loop
|
||||
}
|
||||
}
|
||||
|
||||
func TestReaderReset(t *testing.T) {
|
||||
gold := bytes.Repeat([]byte("All that is gold does not glitter,\n"), 10000)
|
||||
buf := new(bytes.Buffer)
|
||||
if _, err := NewWriter(buf).Write(gold); err != nil {
|
||||
t.Fatalf("Write: %v", err)
|
||||
}
|
||||
encoded, invalid, partial := buf.String(), "invalid", "partial"
|
||||
r := NewReader(nil)
|
||||
for i, s := range []string{encoded, invalid, partial, encoded, partial, invalid, encoded, encoded} {
|
||||
if s == partial {
|
||||
r.Reset(strings.NewReader(encoded))
|
||||
if _, err := r.Read(make([]byte, 101)); err != nil {
|
||||
t.Errorf("#%d: %v", i, err)
|
||||
continue
|
||||
}
|
||||
continue
|
||||
}
|
||||
r.Reset(strings.NewReader(s))
|
||||
got, err := ioutil.ReadAll(r)
|
||||
switch s {
|
||||
case encoded:
|
||||
if err != nil {
|
||||
t.Errorf("#%d: %v", i, err)
|
||||
continue
|
||||
}
|
||||
if err := cmp(got, gold); err != nil {
|
||||
t.Errorf("%#d: %v", i, err)
|
||||
continue
|
||||
}
|
||||
case invalid:
|
||||
if err == nil {
|
||||
t.Errorf("#%d: got nil error, want non-nil", i)
|
||||
continue
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestWriterReset(t *testing.T) {
|
||||
gold := bytes.Repeat([]byte("Not all those who wander are lost;\n"), 10000)
|
||||
var gots, wants [][]byte
|
||||
const n = 20
|
||||
w, failed := NewWriter(nil), false
|
||||
for i := 0; i <= n; i++ {
|
||||
buf := new(bytes.Buffer)
|
||||
w.Reset(buf)
|
||||
want := gold[:len(gold)*i/n]
|
||||
if _, err := w.Write(want); err != nil {
|
||||
t.Errorf("#%d: Write: %v", i, err)
|
||||
failed = true
|
||||
continue
|
||||
}
|
||||
got, err := ioutil.ReadAll(NewReader(buf))
|
||||
if err != nil {
|
||||
t.Errorf("#%d: ReadAll: %v", i, err)
|
||||
failed = true
|
||||
continue
|
||||
}
|
||||
gots = append(gots, got)
|
||||
wants = append(wants, want)
|
||||
}
|
||||
if failed {
|
||||
return
|
||||
}
|
||||
for i := range gots {
|
||||
if err := cmp(gots[i], wants[i]); err != nil {
|
||||
t.Errorf("#%d: %v", i, err)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
Загрузка…
Ссылка в новой задаче