Added SetComplexity to decoder

decoder.go

@@ -18,6 +18,17 @@ bridge_decoder_get_last_packet_duration(OpusDecoder *st, opus_int32 *samples)
 {
 	return opus_decoder_ctl(st, OPUS_GET_LAST_PACKET_DURATION(samples));
 }
+
+#define BRIDGE_ERR_NOT_SUPPORTED -12345
+
+int
+bridge_decoder_set_complexity(OpusDecoder *st, opus_int32 complexity)
+{
+#if defined(OPUS_SET_COMPLEXITY)
+	return opus_decoder_ctl(st, OPUS_SET_COMPLEXITY(complexity));
+#endif
+	return BRIDGE_ERR_NOT_SUPPORTED;
+}
 */
 import "C"
 
@@ -260,3 +271,18 @@ func (dec *Decoder) LastPacketDuration() (int, error) {
 	}
 	return int(samples), nil
 }
+
+const bridgeErrUnimplemented = C.BRIDGE_ERR_NOT_SUPPORTED
+
+// SetComplexity sets the decoders's computational complexity
+// Note that this feature is only available if using libopus >= 1.5
+func (dec *Decoder) SetComplexity(complexity int) error {
+	res := int(C.bridge_decoder_set_complexity(dec.p, C.int(complexity)))
+	if res == bridgeErrUnimplemented {
+		return fmt.Errorf("SetComplexity for decoders requires libopus 1.5 or higher")
+	}
+	if res != int(C.OPUS_OK) {
+		return Error(res)
+	}
+	return nil
+}

decoder_test.go

@@ -5,6 +5,7 @@
 package opus
 
 import (
+	"fmt"
 	"testing"
 )
 
@@ -66,3 +67,30 @@ func TestDecoder_GetLastPacketDuration(t *testing.T) {
 		t.Fatalf("Wrong duration length. Expected %d. Got %d", n, samples)
 	}
 }
+
+func TestDecoder_SetComplexity(t *testing.T) {
+	const SAMPLE_RATE = 48000
+
+	dec, err := NewDecoder(SAMPLE_RATE, 1)
+	if err != nil || dec == nil {
+		t.Fatalf("Error creating new decoder: %v", err)
+	}
+
+	t.Run("Complexity 0 to 10", func(t *testing.T) {
+		for i := 0; i <= 10; i++ {
+			err = dec.SetComplexity(i)
+			if err != nil {
+				t.Fatalf("Expected nil got %v", err)
+			}
+		}
+	})
+
+	for _, tt := range []int{-1, 11, 99} {
+		t.Run(fmt.Sprintf("Complexity %d", tt), func(t *testing.T) {
+			err = dec.SetComplexity(tt)
+			if err != ErrBadArg {
+				t.Fatalf("Expected %v got %v", ErrBadArg, err)
+			}
+		})
+	}
+}