pcm_mix: implemented 32 bit support

NEWS

@@ -71,7 +71,7 @@ ver 0.16 (20??/??/??)
 * database: eliminated maximum line length
 * log: redirect stdout/stderr to /dev/null if syslog is used
 * set the close-on-exec flag on all file descriptors
-* pcm_volume: implemented 32 bit support
+* pcm_volume, pcm_mix: implemented 32 bit support
 * obey $(sysconfdir) for default mpd.conf location
 * build with large file support by default
 * require GLib 2.12

src/pcm_mix.c

@@ -82,6 +82,23 @@ pcm_add_24(int32_t *buffer1, const int32_t *buffer2,
 }
 
 static void
+pcm_add_32(int32_t *buffer1, const int32_t *buffer2,
+	   unsigned num_samples, unsigned volume1, unsigned volume2)
+{
+	while (num_samples > 0) {
+		int64_t sample1 = *buffer1;
+		int64_t sample2 = *buffer2++;
+
+		sample1 = ((sample1 * volume1 + sample2 * volume2) +
+			   pcm_volume_dither() + PCM_VOLUME_1 / 2)
+			/ PCM_VOLUME_1;
+
+		*buffer1++ = pcm_range_64(sample1, 32);
+		--num_samples;
+	}
+}
+
+static void
 pcm_add(void *buffer1, const void *buffer2, size_t size,
 	int vol1, int vol2,
 	const struct audio_format *format)
@@ -103,6 +120,12 @@ pcm_add(void *buffer1, const void *buffer2, size_t size,
 			   size / 4, vol1, vol2);
 		break;
 
+	case 32:
+		pcm_add_32((int32_t*)buffer1,
+			   (const int32_t*)buffer2,
+			   size / 4, vol1, vol2);
+		break;
+
 	default:
 		g_error("%u bits not supported by pcm_add!\n", format->bits);
 	}