libflac: Add support for Reader and Writer I/O
Add support for encoding to a Writer and decoding from a Reader object.
This commit is contained in:
Will Newton
parent
65ef819a46
commit
b583070538
20
cfuncs.go
20
cfuncs.go
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@ -34,6 +34,26 @@ decoderWriteCallback_cgo(const FLAC__StreamDecoder *decoder,
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return decoderWriteCallback(decoder, frame, buffer, data);
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}
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FLAC__StreamDecoderReadStatus
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decoderReadCallback_cgo(const FLAC__StreamDecoder *decoder,
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const FLAC__byte buffer[],
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size_t *bytes,
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void *data)
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{
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return decoderReadCallback(decoder, buffer, bytes, data);
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}
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FLAC__StreamEncoderWriteStatus
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encoderWriteCallback_cgo(const FLAC__StreamEncoder *encoder,
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const FLAC__byte buffer[],
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size_t bytes, unsigned samples,
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unsigned current_frame,
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void *data)
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{
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return encoderWriteCallback(encoder, buffer, bytes, samples, current_frame,
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data);
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}
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extern const char *
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get_decoder_error_str(FLAC__StreamDecoderErrorStatus status)
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{
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119
libflac.go
119
libflac.go
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@ -9,6 +9,7 @@ import (
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"errors"
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"fmt"
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"io"
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"reflect"
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"runtime"
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"unsafe"
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)
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@ -46,6 +47,18 @@ typedef FLAC__StreamDecoderWriteStatus (*decoderWriteCallbackFn)(const FLAC__Str
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const FLAC__Frame *,
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const FLAC__int32 **,
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void *);
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FLAC__StreamDecoderReadStatus
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decoderReadCallback_cgo(const FLAC__StreamDecoder *,
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const FLAC__byte *,
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size_t *,
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void *);
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FLAC__StreamEncoderWriteStatus
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encoderWriteCallback_cgo(const FLAC__StreamEncoder *,
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const FLAC__byte *,
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size_t, unsigned,
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unsigned,
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void *);
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extern const char *
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@ -78,6 +91,7 @@ type Frame struct {
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// Decoder is a FLAC decoder.
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type Decoder struct {
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d *C.FLAC__StreamDecoder
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reader io.ReadCloser
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Channels int
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Depth int
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Rate int
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@ -89,6 +103,7 @@ type Decoder struct {
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// Encoder is a FLAC encoder.
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type Encoder struct {
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e *C.FLAC__StreamEncoder
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writer io.WriteCloser
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Channels int
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Depth int
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Rate int
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@ -125,6 +140,29 @@ func decoderWriteCallback(d *C.FLAC__StreamDecoder, frame *C.FLAC__Frame, buffer
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return C.FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE
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}
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//export decoderReadCallback
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func decoderReadCallback(d *C.FLAC__StreamDecoder, buffer *C.FLAC__byte, bytes *C.size_t, data unsafe.Pointer) C.FLAC__StreamDecoderReadStatus {
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decoder := (*Decoder)(data)
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numBytes := int(*bytes)
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if numBytes <= 0 {
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return C.FLAC__STREAM_DECODER_READ_STATUS_ABORT
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}
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hdr := reflect.SliceHeader{
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Data: uintptr(unsafe.Pointer(buffer)),
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Len: numBytes,
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Cap: numBytes,
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}
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buf := *(*[]byte)(unsafe.Pointer(&hdr))
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n, err := decoder.reader.Read(buf)
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*bytes = C.size_t(n)
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if err == io.EOF && n == 0 {
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return C.FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM
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} else if err != nil && err != io.EOF {
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return C.FLAC__STREAM_DECODER_READ_STATUS_ABORT
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}
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return C.FLAC__STREAM_DECODER_READ_STATUS_CONTINUE
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}
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// NewDecoder creates a new Decoder object.
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func NewDecoder(name string) (d *Decoder, err error) {
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d = new(Decoder)
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@ -150,12 +188,41 @@ func NewDecoder(name string) (d *Decoder, err error) {
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return
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}
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// NewDecoderReader creates a new Decoder object from a Reader.
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func NewDecoderReader(reader io.ReadCloser) (d *Decoder, err error) {
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d = new(Decoder)
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d.d = C.FLAC__stream_decoder_new()
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if d.d == nil {
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return nil, errors.New("failed to create decoder")
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}
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d.reader = reader
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runtime.SetFinalizer(d, (*Decoder).Close)
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status := C.FLAC__stream_decoder_init_stream(d.d,
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(C.FLAC__StreamDecoderReadCallback)(unsafe.Pointer(C.decoderReadCallback_cgo)),
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nil, nil, nil, nil,
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(C.decoderWriteCallbackFn)(unsafe.Pointer(C.decoderWriteCallback_cgo)),
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(C.decoderMetadataCallbackFn)(unsafe.Pointer(C.decoderMetadataCallback_cgo)),
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(C.decoderErrorCallbackFn)(unsafe.Pointer(C.decoderErrorCallback_cgo)),
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unsafe.Pointer(d))
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if status != C.FLAC__STREAM_DECODER_INIT_STATUS_OK {
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return nil, errors.New("failed to open stream")
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}
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ret := C.FLAC__stream_decoder_process_until_end_of_metadata(d.d)
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if ret == 0 || d.error == true || d.Channels == 0 {
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return nil, fmt.Errorf("failed to process metadata %s", d.errorStr)
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}
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return
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}
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// Close closes a decoder and frees the resources.
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func (d *Decoder) Close() {
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if d.d != nil {
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C.FLAC__stream_decoder_delete(d.d)
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d.d = nil
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}
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if d.reader != nil {
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d.reader.Close()
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}
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runtime.SetFinalizer(d, nil)
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}
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@ -203,6 +270,55 @@ func NewEncoder(name string, channels int, depth int, rate int) (e *Encoder, err
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return
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}
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//export encoderWriteCallback
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func encoderWriteCallback(e *C.FLAC__StreamEncoder, buffer *C.FLAC__byte, bytes C.size_t, samples, current_frame C.unsigned, data unsafe.Pointer) C.FLAC__StreamEncoderWriteStatus {
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encoder := (*Encoder)(data)
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numBytes := int(bytes)
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if numBytes <= 0 {
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return C.FLAC__STREAM_DECODER_READ_STATUS_ABORT
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}
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hdr := reflect.SliceHeader{
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Data: uintptr(unsafe.Pointer(buffer)),
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Len: numBytes,
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Cap: numBytes,
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}
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buf := *(*[]byte)(unsafe.Pointer(&hdr))
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_, err := encoder.writer.Write(buf)
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if err != nil {
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return C.FLAC__STREAM_ENCODER_WRITE_STATUS_FATAL_ERROR
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}
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return C.FLAC__STREAM_ENCODER_WRITE_STATUS_OK
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}
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// NewEncoderWriter creates a new Encoder object from a Writer.
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func NewEncoderWriter(writer io.WriteCloser, channels int, depth int, rate int) (e *Encoder, err error) {
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if channels == 0 {
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return nil, errors.New("channels must be greater than 0")
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}
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if !(depth == 16 || depth == 24) {
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return nil, errors.New("depth must be 16 or 24")
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}
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e = new(Encoder)
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e.e = C.FLAC__stream_encoder_new()
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if e.e == nil {
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return nil, errors.New("failed to create decoder")
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}
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e.writer = writer
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runtime.SetFinalizer(e, (*Encoder).Close)
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C.FLAC__stream_encoder_set_channels(e.e, C.uint(channels))
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C.FLAC__stream_encoder_set_bits_per_sample(e.e, C.uint(depth))
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C.FLAC__stream_encoder_set_sample_rate(e.e, C.uint(rate))
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status := C.FLAC__stream_encoder_init_stream(e.e,
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(C.FLAC__StreamEncoderWriteCallback)(unsafe.Pointer(C.encoderWriteCallback_cgo)), nil, nil, nil, unsafe.Pointer(e))
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if status != C.FLAC__STREAM_ENCODER_INIT_STATUS_OK {
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return nil, errors.New("failed to open file")
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}
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e.Channels = channels
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e.Depth = depth
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e.Rate = rate
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return
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}
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// WriteFrame writes a frame of audio data to the encoder.
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func (e *Encoder) WriteFrame(f Frame) (err error) {
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if f.Channels != e.Channels || f.Depth != e.Depth || f.Rate != e.Rate {
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@ -224,5 +340,8 @@ func (e *Encoder) Close() {
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C.FLAC__stream_encoder_finish(e.e)
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e.e = nil
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}
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if e.writer != nil {
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e.writer.Close()
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}
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runtime.SetFinalizer(e, nil)
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}
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@ -58,6 +58,57 @@ func TestDecode(t *testing.T) {
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d.Close()
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}
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func TestDecodeReader(t *testing.T) {
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a := assert.New(t)
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reader, _ := os.Open("data/nonexistent.flac")
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d, err := NewDecoderReader(reader)
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a.Equal(d, (*Decoder)(nil), "decoder is nil")
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a.Error(err)
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reader, _ = os.Open("data/sine24-00.flac")
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d, err = NewDecoderReader(reader)
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a.Equal(err, nil, "err is nil")
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a.Equal(d.Channels, 1, "channels is 1")
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a.Equal(d.Depth, 24, "depth is 24")
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a.Equal(d.Rate, 48000, "depth is 48000")
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samples := 0
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f, err := d.ReadFrame()
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a.Equal(err, nil, "err is nil")
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a.Equal(f.Channels, 1, "channels is 1")
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a.Equal(f.Depth, 24, "depth is 24")
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a.Equal(f.Rate, 48000, "depth is 48000")
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samples = samples + len(f.Buffer)
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for {
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f, err := d.ReadFrame()
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if err == nil || err == io.EOF {
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if f != nil {
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samples = samples + len(f.Buffer)
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}
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} else {
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a.Equal(err, nil, "error reported")
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break
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}
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if err == io.EOF {
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break
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}
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}
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a.Equal(samples, 200000, "all samples read")
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d.Close()
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}
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func TestEncode(t *testing.T) {
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a := assert.New(t)
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@ -164,3 +215,45 @@ func TestRoundTripStereo(t *testing.T) {
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os.Remove(outputFile)
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}
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func TestRoundTripReaderWriter(t *testing.T) {
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a := assert.New(t)
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inputFile := "data/sine24-00.flac"
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outputFile := "data/test.flac"
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reader, _ := os.Open(inputFile)
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d, err := NewDecoderReader(reader)
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a.Equal(err, nil, "err is nil")
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writer, _ := os.Create(outputFile)
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e, err := NewEncoderWriter(writer, d.Channels, d.Depth, d.Rate)
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samples := 0
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for {
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f, err := d.ReadFrame()
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if err == nil || err == io.EOF {
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if f != nil {
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_ = e.WriteFrame(*f)
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samples = samples + len(f.Buffer)
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}
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} else {
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a.Equal(err, nil, "error reported")
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break
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}
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if err == io.EOF {
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break
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}
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}
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a.Equal(samples, 200000, "all samples read")
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d.Close()
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e.Close()
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os.Remove(outputFile)
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}
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