codec: H264 and MJPEG lexers now using codecutil package for byte scanner functionality

This commit is contained in:
Saxon 2019-05-22 11:07:39 +09:30
parent f52acc7efb
commit 980cf8da21
6 changed files with 8 additions and 241 deletions

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@ -23,7 +23,7 @@ LICENSE
*/
// Package bytescan implements a byte-level scanner.
package bytescan
package codecutil
import "io"

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@ -25,7 +25,7 @@ LICENSE
in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package bytescan
package codecutil
import (
"bytes"

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@ -32,6 +32,8 @@ package h264
import (
"io"
"time"
"bitbucket.org/ausocean/av/codec/codecutil"
)
var noDelay = make(chan time.Time)
@ -58,7 +60,7 @@ func Lex(dst io.Writer, src io.Reader, delay time.Duration) error {
const bufSize = 8 << 10
c := newScanner(src, make([]byte, 4<<10)) // Standard file buffer size.
c := codecutil.NewByteScanner(src, make([]byte, 4<<10)) // Standard file buffer size.
buf := make([]byte, len(h264Prefix), bufSize)
copy(buf, h264Prefix[:])
@ -67,7 +69,7 @@ outer:
for {
var b byte
var err error
buf, b, err = c.scanUntilZeroInto(buf)
buf, b, err = c.ScanUntil(buf, 0x00)
if err != nil {
if err != io.EOF {
return err
@ -76,7 +78,7 @@ outer:
}
for n := 1; b == 0x0 && n < 4; n++ {
b, err = c.readByte()
b, err = c.ReadByte()
if err != nil {
if err != io.EOF {
return err
@ -101,7 +103,7 @@ outer:
writeOut = false
}
b, err = c.readByte()
b, err = c.ReadByte()
if err != nil {
if err != io.EOF {
return err
@ -131,70 +133,3 @@ outer:
_, err := dst.Write(buf)
return err
}
// scanner is a byte scanner.
type scanner struct {
buf []byte
off int
// r is the source of data for the scanner.
r io.Reader
}
// newScanner returns a scanner initialised with an io.Reader and a read buffer.
func newScanner(r io.Reader, buf []byte) *scanner {
return &scanner{r: r, buf: buf[:0]}
}
// scanUntilZeroInto scans the scanner's underlying io.Reader until a zero byte
// has been read, appending all read bytes to dst. The resulting appended data,
// the last read byte and whether the last read byte was zero are returned.
func (c *scanner) scanUntilZeroInto(dst []byte) (res []byte, b byte, err error) {
outer:
for {
var i int
for i, b = range c.buf[c.off:] {
if b != 0x0 {
continue
}
dst = append(dst, c.buf[c.off:c.off+i+1]...)
c.off += i + 1
break outer
}
dst = append(dst, c.buf[c.off:]...)
err = c.reload()
if err != nil {
break
}
}
return dst, b, err
}
// readByte is an unexported ReadByte.
func (c *scanner) readByte() (byte, error) {
if c.off >= len(c.buf) {
err := c.reload()
if err != nil {
return 0, err
}
}
b := c.buf[c.off]
c.off++
return b, nil
}
// reload re-fills the scanner's buffer.
func (c *scanner) reload() error {
n, err := c.r.Read(c.buf[:cap(c.buf)])
c.buf = c.buf[:n]
if err != nil {
if err != io.EOF {
return err
}
if n == 0 {
return io.EOF
}
}
c.off = 0
return nil
}

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@ -30,9 +30,6 @@ LICENSE
package h264
import (
"bytes"
"reflect"
"testing"
"time"
)
@ -223,50 +220,3 @@ func TestH264(t *testing.T) {
}
}
*/
type chunkEncoder [][]byte
func (e *chunkEncoder) Encode(b []byte) error {
*e = append(*e, b)
return nil
}
func (*chunkEncoder) Stream() <-chan []byte { panic("INVALID USE") }
func TestScannerReadByte(t *testing.T) {
data := []byte("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
for _, size := range []int{1, 2, 8, 1 << 10} {
r := newScanner(bytes.NewReader(data), make([]byte, size))
var got []byte
for {
b, err := r.readByte()
if err != nil {
break
}
got = append(got, b)
}
if !bytes.Equal(got, data) {
t.Errorf("unexpected result for buffer size %d:\ngot :%q\nwant:%q", size, got, data)
}
}
}
func TestScannerScanUntilZero(t *testing.T) {
data := []byte("Lorem ipsum dolor sit amet, consectetur adipiscing elit,\x00 sed do eiusmod tempor incididunt ut \x00labore et dolore magna aliqua.")
for _, size := range []int{1, 2, 8, 1 << 10} {
r := newScanner(bytes.NewReader(data), make([]byte, size))
var got [][]byte
for {
buf, _, err := r.scanUntilZeroInto(nil)
got = append(got, buf)
if err != nil {
break
}
}
want := bytes.SplitAfter(data, []byte{0})
if !reflect.DeepEqual(got, want) {
t.Errorf("unexpected result for buffer zie %d:\ngot :%q\nwant:%q", size, got, want)
}
}
}

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@ -87,70 +87,3 @@ func Lex(dst io.Writer, src io.Reader, delay time.Duration) error {
}
}
}
// scanner is a byte scanner.
type scanner struct {
buf []byte
off int
// r is the source of data for the scanner.
r io.Reader
}
// newScanner returns a scanner initialised with an io.Reader and a read buffer.
func newScanner(r io.Reader, buf []byte) *scanner {
return &scanner{r: r, buf: buf[:0]}
}
// scanUntilZeroInto scans the scanner's underlying io.Reader until a zero byte
// has been read, appending all read bytes to dst. The resulting appended data,
// the last read byte and whether the last read byte was zero are returned.
func (c *scanner) scanUntilZeroInto(dst []byte) (res []byte, b byte, err error) {
outer:
for {
var i int
for i, b = range c.buf[c.off:] {
if b != 0x0 {
continue
}
dst = append(dst, c.buf[c.off:c.off+i+1]...)
c.off += i + 1
break outer
}
dst = append(dst, c.buf[c.off:]...)
err = c.reload()
if err != nil {
break
}
}
return dst, b, err
}
// readByte is an unexported ReadByte.
func (c *scanner) readByte() (byte, error) {
if c.off >= len(c.buf) {
err := c.reload()
if err != nil {
return 0, err
}
}
b := c.buf[c.off]
c.off++
return b, nil
}
// reload re-fills the scanner's buffer.
func (c *scanner) reload() error {
n, err := c.r.Read(c.buf[:cap(c.buf)])
c.buf = c.buf[:n]
if err != nil {
if err != io.EOF {
return err
}
if n == 0 {
return io.EOF
}
}
c.off = 0
return nil
}

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@ -30,9 +30,6 @@ LICENSE
package mjpeg
import (
"bytes"
"reflect"
"testing"
"time"
)
@ -115,51 +112,3 @@ func Lex(t *testing.T) {
}
}
*/
type chunkEncoder [][]byte
func (e *chunkEncoder) Encode(b []byte) error {
*e = append(*e, b)
return nil
}
func (*chunkEncoder) Stream() <-chan []byte { panic("INVALID USE") }
func TestScannerReadByte(t *testing.T) {
data := []byte("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
for _, size := range []int{1, 2, 8, 1 << 10} {
r := newScanner(bytes.NewReader(data), make([]byte, size))
var got []byte
for {
b, err := r.readByte()
if err != nil {
break
}
got = append(got, b)
}
if !bytes.Equal(got, data) {
t.Errorf("unexpected result for buffer size %d:\ngot :%q\nwant:%q", size, got, data)
}
}
}
func TestScannerScanUntilZero(t *testing.T) {
data := []byte("Lorem ipsum dolor sit amet, consectetur adipiscing elit,\x00 sed do eiusmod tempor incididunt ut \x00labore et dolore magna aliqua.")
for _, size := range []int{1, 2, 8, 1 << 10} {
r := newScanner(bytes.NewReader(data), make([]byte, size))
var got [][]byte
for {
buf, _, err := r.scanUntilZeroInto(nil)
got = append(got, buf)
if err != nil {
break
}
}
want := bytes.SplitAfter(data, []byte{0})
if !reflect.DeepEqual(got, want) {
t.Errorf("unexpected result for buffer zie %d:\ngot :%q\nwant:%q", size, got, want)
}
}
}