1 files changed, 148 insertions, 0 deletions
diff --git a/src/filter/VolumeFilterPlugin.cxx b/src/filter/VolumeFilterPlugin.cxx
new file mode 100644
index 00000000..0689f5da
--- /dev/null
+++ b/src/filter/VolumeFilterPlugin.cxx
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "VolumeFilterPlugin.hxx"
+#include "FilterPlugin.hxx"
+#include "FilterInternal.hxx"
+#include "FilterRegistry.hxx"
+#include "conf.h"
+#include "pcm_buffer.h"
+#include "PcmVolume.hxx"
+#include "audio_format.h"
+
+#include <assert.h>
+#include <string.h>
+
+class VolumeFilter final : public Filter {
+	/**
+	 * The current volume, from 0 to #PCM_VOLUME_1.
+	 */
+	unsigned volume;
+
+	struct audio_format format;
+
+	struct pcm_buffer buffer;
+
+public:
+	VolumeFilter()
+		:volume(PCM_VOLUME_1) {}
+
+	unsigned GetVolume() const {
+		assert(volume <= PCM_VOLUME_1);
+
+		return volume;
+	}
+
+	void SetVolume(unsigned _volume) {
+		assert(_volume <= PCM_VOLUME_1);
+
+		volume = _volume;
+	}
+
+	virtual const audio_format *Open(audio_format &af, GError **error_r);
+	virtual void Close();
+	virtual const void *FilterPCM(const void *src, size_t src_size,
+				      size_t *dest_size_r, GError **error_r);
+};
+
+static inline GQuark
+volume_quark(void)
+{
+	return g_quark_from_static_string("pcm_volume");
+}
+
+static Filter *
+volume_filter_init(gcc_unused const struct config_param *param,
+		   gcc_unused GError **error_r)
+{
+	return new VolumeFilter();
+}
+
+const struct audio_format *
+VolumeFilter::Open(audio_format &audio_format, gcc_unused GError **error_r)
+{
+	format = audio_format;
+	pcm_buffer_init(&buffer);
+
+	return &format;
+}
+
+void
+VolumeFilter::Close()
+{
+	pcm_buffer_deinit(&buffer);
+}
+
+const void *
+VolumeFilter::FilterPCM(const void *src, size_t src_size,
+			size_t *dest_size_r, GError **error_r)
+{
+	*dest_size_r = src_size;
+
+	if (volume >= PCM_VOLUME_1)
+		/* optimized special case: 100% volume = no-op */
+		return src;
+
+	void *dest = pcm_buffer_get(&buffer, src_size);
+
+	if (volume <= 0) {
+		/* optimized special case: 0% volume = memset(0) */
+		/* XXX is this valid for all sample formats? What
+		   about floating point? */
+		memset(dest, 0, src_size);
+		return dest;
+	}
+
+	memcpy(dest, src, src_size);
+
+	bool success = pcm_volume(dest, src_size,
+				  sample_format(format.format),
+				  volume);
+	if (!success) {
+		g_set_error(error_r, volume_quark(), 0,
+			    "pcm_volume() has failed");
+		return NULL;
+	}
+
+	return dest;
+}
+
+const struct filter_plugin volume_filter_plugin = {
+	"volume",
+	volume_filter_init,
+};
+
+unsigned
+volume_filter_get(const Filter *_filter)
+{
+	const VolumeFilter *filter =
+		(const VolumeFilter *)_filter;
+
+	return filter->GetVolume();
+}
+
+void
+volume_filter_set(Filter *_filter, unsigned volume)
+{
+	VolumeFilter *filter = (VolumeFilter *)_filter;
+
+	filter->SetVolume(volume);
+}
+