1 files changed, 105 insertions, 0 deletions
diff --git a/src/pcm_volume.c b/src/pcm_volume.c
new file mode 100644
index 000000000..af7916b1f
--- /dev/null
+++ b/src/pcm_volume.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "pcm_volume.h"
+#include "pcm_utils.h"
+#include "audio_format.h"
+
+#include <glib.h>
+
+#include <stdint.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "pcm_volume"
+
+static void
+pcm_volume_change_8(int8_t *buffer, unsigned num_samples, int volume)
+{
+	while (num_samples > 0) {
+		int32_t sample = *buffer;
+
+		sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
+			/ PCM_VOLUME_1;
+
+		*buffer++ = pcm_range(sample, 8);
+		--num_samples;
+	}
+}
+
+static void
+pcm_volume_change_16(int16_t *buffer, unsigned num_samples, int volume)
+{
+	while (num_samples > 0) {
+		int32_t sample = *buffer;
+
+		sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
+			/ PCM_VOLUME_1;
+
+		*buffer++ = pcm_range(sample, 16);
+		--num_samples;
+	}
+}
+
+static void
+pcm_volume_change_24(int32_t *buffer, unsigned num_samples, int volume)
+{
+	while (num_samples > 0) {
+		int64_t sample = *buffer;
+
+		sample = (sample * volume + pcm_dither() + PCM_VOLUME_1 / 2)
+			/ PCM_VOLUME_1;
+
+		*buffer++ = pcm_range(sample, 24);
+		--num_samples;
+	}
+}
+
+void
+pcm_volume(char *buffer, int bufferSize,
+	   const struct audio_format *format,
+	   int volume)
+{
+	if (volume == PCM_VOLUME_1)
+		return;
+
+	if (volume <= 0) {
+		memset(buffer, 0, bufferSize);
+		return;
+	}
+
+	switch (format->bits) {
+	case 8:
+		pcm_volume_change_8((int8_t *)buffer, bufferSize, volume);
+		break;
+
+	case 16:
+		pcm_volume_change_16((int16_t *)buffer, bufferSize / 2,
+				     volume);
+		break;
+
+	case 24:
+		pcm_volume_change_24((int32_t*)buffer, bufferSize / 4,
+				     volume);
+		break;
+
+	default:
+		g_error("%u bits not supported by pcm_volume!\n",
+			format->bits);
+	}
+}