just working with downloader

1 files changed, 78 insertions, 17 deletions

diff --git a/wav/wav.go b/wav/wav.go
index 8556d60..c505a32 100644
--- a/wav/wav.go
+++ b/wav/wav.go
@@ -6,63 +6,126 @@ import "C"
 import (
 	"fmt"
 
+	"sync"
+
 	"github.com/op/go-logging"
 	"layeh.com/gopus"
 )
 
+type State int
+
+const (
+	Pause State = iota
+	Resume
+)
+
 // number of individual samples per channel per batch
 const samplesPerChannelPerBatch = 1920
 
 var log = logging.MustGetLogger("wav")
 
-func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
+type Wav struct {
+	filename *C.char
+	enc      *gopus.Encoder
+	wav      *C.drwav
+
+	PlayState chan State
+	curState  State
+
+	once sync.Once
+	Done <-chan struct{}
+	done chan<- struct{}
+}
+
+func New(filename string) (*Wav, error) {
 	cfname := C.CString(filename)
 	wav := C.drwav_open_file(cfname)
 	if wav == nil {
-		close(ch)
+		C.drwav_close(wav)
 		return nil, fmt.Errorf("Unable to initialize drwav.")
 	}
 
 	if int(wav.channels) != 2 {
 		C.drwav_close(wav)
-		close(ch)
 		return nil, fmt.Errorf("Wrong number of channels!")
 	}
 
 	if int(wav.sampleRate) != 48000 {
 		C.drwav_close(wav)
-		close(ch)
 		return nil, fmt.Errorf("Wrong sample rate.")
 	}
 
 	enc, err := gopus.NewEncoder(int(wav.sampleRate), int(wav.channels), gopus.Audio)
 	if err != nil {
-		close(ch)
+		C.drwav_close(wav)
 		return nil, err
 	}
 
 	done := make(chan struct{}, 1)
-	go func(wav *C.drwav) {
-		defer close(done)
-		defer close(ch)
+	return &Wav{
+		filename: C.CString(filename),
+		enc:      enc,
+		wav:      wav,
+
+		PlayState: make(chan State),
+		curState:  Resume,
 
-		samplesPerBatch := samplesPerChannelPerBatch * int(wav.channels)
-		batchSize := samplesPerBatch * int(wav.bytesPerSample)
+		done: done,
+		Done: done,
+	}, nil
+}
+
+func (w *Wav) Stop() {
+	w.once.Do(func() {
+		close(w.done)
+	})
+}
+
+func (w *Wav) Start(ch chan<- []byte) {
+	go func() {
+		defer w.Stop()
+
+		samplesPerBatch := samplesPerChannelPerBatch * int(w.wav.channels)
+		batchSize := samplesPerBatch * int(w.wav.bytesPerSample)
 
 		buf := C.malloc(C.size_t(batchSize))
 		defer C.free(buf)
-		defer C.drwav_close(wav)
+		defer C.drwav_close(w.wav)
 
 		elems := make([]int16, samplesPerBatch)
 		idx := 0
 
-		for i := 0; i*samplesPerBatch <= int(wav.totalSampleCount); i += 1 {
-			readSamples := C.drwav_read_s16(wav, C.dr_uint64(samplesPerBatch), (*C.dr_int16)(buf))
+		for i := 0; i*samplesPerBatch <= int(w.wav.totalSampleCount); i += 1 {
+			readSamples := C.drwav_read_s16(w.wav, C.dr_uint64(samplesPerBatch), (*C.dr_int16)(buf))
 			slc := (*[1 << 30]int16)(buf)[:readSamples:readSamples]
 
 			readIdx := 0
 
+		inner:
 			for {
+				// check to see if we should die or pause
+				if w.curState == Pause { // if paused wait to die or get resumed
+					select {
+					case st := <-w.PlayState:
+						w.curState = st
+						continue inner
+
+					case <-w.Done:
+						return
+					}
+
+				} else {
+					select {
+					case st := <-w.PlayState:
+						w.curState = st
+						continue inner
+
+					case <-w.Done:
+						return
+					default:
+					}
+				}
+
 				batchSamplesToFill := samplesPerBatch - idx
 				readSamplesRemaining := int(readSamples) - readIdx
 
@@ -75,7 +138,7 @@ func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
 				idx = 0
 				readIdx += batchSamplesToFill
 
-				b, err := processPCM(wav, enc, elems[:])
+				b, err := processPCM(w.wav, w.enc, elems[:])
 				if err != nil {
 					log.Errorf("error encoding pcm: %q", err)
 					continue
@@ -96,9 +159,7 @@ func Load(filename string, ch chan<- []byte) (<-chan struct{}, error) {
 				break
 			}
 		}
-	}(wav)
-
-	return done, nil
+	}()
 }
 
 func processPCM(wav *C.drwav, enc *gopus.Encoder, data []int16) ([]byte, error) {