From c5395ca98ad8644bd73166b75a88ac79121211ca Mon Sep 17 00:00:00 2001
From: Hraban Luyat <hraban@0brg.net>
Date: Sun, 5 Jul 2015 21:03:21 +0100
Subject: [PATCH] Change stream reader API to look like io.Reader

---
 stream.go      | 23 ++++++++++++++++-------
 stream_test.go | 19 +++++++++++++++++++
 2 files changed, 35 insertions(+), 7 deletions(-)
 create mode 100644 stream_test.go

diff --git a/stream.go b/stream.go
index 5e0c863..de8dbae 100644
--- a/stream.go
+++ b/stream.go
@@ -63,8 +63,9 @@ func (s *Stream) Init(read io.Reader) error {
 		return fmt.Errorf("opus stream is already initialized")
 	}
 	if read == nil {
-		return fmt.Errorf("Reader function must be non-nil")
+		return fmt.Errorf("Reader must be non-nil")
 	}
+	s.read = read
 	var errno C.int
 	oggfile := C.op_open_callbacks(
 		unsafe.Pointer(s),
@@ -80,20 +81,28 @@ func (s *Stream) Init(read io.Reader) error {
 	return nil
 }
 
-func (s *Stream) Read() ([]int16, error) {
+// Read a chunk of raw opus data from the stream and decode it. Returns the
+// number of decoded samples per channel. This means that a dual channel
+// (stereo) feed will have twice as many samples as the value returned.
+func (s *Stream) Read(pcm []int16) (int, error) {
 	if s.oggfile == nil {
-		return nil, fmt.Errorf("opus stream is uninitialized or already closed")
+		return 0, fmt.Errorf("opus stream is uninitialized or already closed")
+	}
+	if len(pcm) == 0 {
+		return 0, nil
 	}
-	pcm := make([]int16, xMAX_FRAME_SIZE)
 	n := C.op_read(
 		s.oggfile,
 		(*C.opus_int16)(&pcm[0]),
-		C.int(cap(pcm)),
+		C.int(len(pcm)),
 		nil)
 	if n < 0 {
-		return nil, opusfileerr(n)
+		return 0, opusfileerr(n)
+	}
+	if n == 0 {
+		return 0, io.EOF
 	}
-	return pcm[:n], nil
+	return int(n), nil
 }
 
 func (s *Stream) Close() error {
diff --git a/stream_test.go b/stream_test.go
new file mode 100644
index 0000000..08c07fd
--- /dev/null
+++ b/stream_test.go
@@ -0,0 +1,19 @@
+// Copyright © 2015 Hraban Luyat <hraban@0brg.net>
+//
+// License for use of this code is detailed in the LICENSE file
+
+package opus
+
+import (
+	"strings"
+	"testing"
+)
+
+func Test(t *testing.T) {
+	// Simple testing, no actual decoding
+	reader := strings.NewReader("hello")
+	_, err := NewStream(reader)
+	if err == nil {
+		t.Fatalf("Expected error while initializing illegal opus stream")
+	}
+}
-- 
2.48.1