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audio/wav: Parse header more accurately

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This commit is contained in:
Hajime Hoshi 2016-03-30 01:30:40 +09:00
parent 50b7ec59d4
commit aba404d39f
1 changed files with 73 additions and 39 deletions
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112
exp/audio/wav/decode.go
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@ -18,74 +18,108 @@ import (
"bytes"
"fmt"
"io"
"io/ioutil"
"github.com/hajimehoshi/ebiten/exp/audio"
)
const (
headerSize = 44
riffHeader = "RIFF"
waveHeader = "WAVE"
)
type Stream struct {
buf *bytes.Reader
src audio.ReadSeekCloser
headerSize int64
dataSize int64
}
func (s *Stream) Read(p []byte) (int, error) {
return s.buf.Read(p)
return s.src.Read(p)
}
func (s *Stream) Seek(offset int64, whence int) (int64, error) {
return s.buf.Seek(offset, whence)
return s.src.Seek(offset+s.headerSize, whence)
}
func (s *Stream) Close() error {
s.buf = nil
return nil
return s.src.Close()
}
func (s *Stream) Size() int64 {
return s.buf.Size()
return s.dataSize
}
// TODO: src should be ReadCloser?
func Decode(context *audio.Context, src io.Reader) (*Stream, error) {
buf := make([]byte, headerSize)
func Decode(context *audio.Context, src audio.ReadSeekCloser) (*Stream, error) {
buf := make([]byte, 12)
n, err := io.ReadFull(src, buf)
if n != headerSize {
if n != len(buf) {
return nil, fmt.Errorf("wav: invalid header")
}
if err != nil {
return nil, err
}
if !bytes.Equal(buf[0:4], []byte(riffHeader)) {
return nil, fmt.Errorf("wav: invalid header: RIFF not found")
if !bytes.Equal(buf[0:4], []byte("RIFF")) {
return nil, fmt.Errorf("wav: invalid header: 'RIFF' not found")
}
if !bytes.Equal(buf[8:12], []byte(waveHeader)) {
return nil, fmt.Errorf("wav: invalid header: WAVE not found")
if !bytes.Equal(buf[8:12], []byte("WAVE")) {
return nil, fmt.Errorf("wav: invalid header: 'WAVE' not found")
}
channels, depth := buf[22], buf[34]
// TODO: Remove this magic number
if channels != 2 {
return nil, fmt.Errorf("wav: invalid header: channel num must be 2")
}
// TODO: Remove this magic number
if depth != 16 {
return nil, fmt.Errorf("wav: invalid header: depth must be 16")
}
sampleRate := int(buf[24]) | int(buf[25])<<8 | int(buf[26])<<16 | int(buf[27]<<24)
if context.SampleRate() != sampleRate {
return nil, fmt.Errorf("wav: sample rate must be %d but %d", context.SampleRate(), sampleRate)
}
b, err := ioutil.ReadAll(src)
if err != nil {
return nil, err
// Read chunks
dataSize := int64(0)
headerSize := int64(0)
chunks:
for {
buf := make([]byte, 8)
n, err := io.ReadFull(src, buf)
if n != len(buf) {
return nil, fmt.Errorf("wav: invalid header")
}
if err != nil {
return nil, err
}
headerSize += 8
size := int64(buf[4]) | int64(buf[5])<<8 | int64(buf[6])<<16 | int64(buf[7]<<24)
switch {
case bytes.Equal(buf[0:4], []byte("fmt ")):
if size != 16 {
return nil, fmt.Errorf("wav: invalid header: maybe non-PCM file?")
}
buf := make([]byte, size)
n, err := io.ReadFull(src, buf)
if n != len(buf) {
return nil, fmt.Errorf("wav: invalid header")
}
if err != nil {
return nil, err
}
// TODO: Remove this magic number
if buf[2] != 2 {
return nil, fmt.Errorf("wav: invalid header: channel num must be 2")
}
// TODO: Remove this magic number
if buf[14] != 16 {
return nil, fmt.Errorf("wav: invalid header: depth must be 16")
}
sampleRate := int64(buf[4]) | int64(buf[5])<<8 | int64(buf[6])<<16 | int64(buf[7]<<24)
if int64(context.SampleRate()) != sampleRate {
return nil, fmt.Errorf("wav: sample rate must be %d but %d", context.SampleRate(), sampleRate)
}
headerSize += size
case bytes.Equal(buf[0:4], []byte("data")):
dataSize = size
break chunks
default:
buf := make([]byte, size)
n, err := io.ReadFull(src, buf)
if n != len(buf) {
return nil, fmt.Errorf("wav: invalid header")
}
if err != nil {
return nil, err
}
headerSize += size
}
}
s := &Stream{
buf: bytes.NewReader(b),
src: src,
headerSize: headerSize,
dataSize: dataSize,
}
return s, nil
}