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-rw-r--r--src/mixer/plugins/SoftwareMixerPlugin.cxx144
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diff --git a/src/mixer/plugins/SoftwareMixerPlugin.cxx b/src/mixer/plugins/SoftwareMixerPlugin.cxx
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+++ b/src/mixer/plugins/SoftwareMixerPlugin.cxx
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+/*
+ * Copyright (C) 2003-2014 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 "SoftwareMixerPlugin.hxx"
+#include "mixer/MixerInternal.hxx"
+#include "filter/FilterPlugin.hxx"
+#include "filter/FilterRegistry.hxx"
+#include "filter/FilterInternal.hxx"
+#include "filter/plugins/VolumeFilterPlugin.hxx"
+#include "pcm/Volume.hxx"
+#include "config/ConfigData.hxx"
+#include "util/Error.hxx"
+
+#include <assert.h>
+#include <math.h>
+
+static Filter *
+CreateVolumeFilter()
+{
+ return filter_new(&volume_filter_plugin, config_param(),
+ IgnoreError());
+}
+
+class SoftwareMixer final : public Mixer {
+ Filter *filter;
+
+ /**
+ * If this is true, then this object "owns" the #Filter
+ * instance (see above). It will be set to false by
+ * software_mixer_get_filter(); after that, the caller will be
+ * responsible for the #Filter.
+ */
+ bool owns_filter;
+
+ /**
+ * The current volume in percent (0..100).
+ */
+ unsigned volume;
+
+public:
+ SoftwareMixer(MixerListener &_listener)
+ :Mixer(software_mixer_plugin, _listener),
+ filter(CreateVolumeFilter()),
+ owns_filter(true),
+ volume(100)
+ {
+ assert(filter != nullptr);
+ }
+
+ virtual ~SoftwareMixer() {
+ if (owns_filter)
+ delete filter;
+ }
+
+ Filter *GetFilter();
+
+ /* virtual methods from class Mixer */
+ virtual bool Open(gcc_unused Error &error) override {
+ return true;
+ }
+
+ virtual void Close() override {
+ }
+
+ virtual int GetVolume(gcc_unused Error &error) override {
+ return volume;
+ }
+
+ virtual bool SetVolume(unsigned volume, Error &error) override;
+};
+
+static Mixer *
+software_mixer_init(gcc_unused EventLoop &event_loop,
+ gcc_unused AudioOutput &ao,
+ MixerListener &listener,
+ gcc_unused const config_param &param,
+ gcc_unused Error &error)
+{
+ return new SoftwareMixer(listener);
+}
+
+gcc_const
+static unsigned
+PercentVolumeToSoftwareVolume(unsigned volume)
+{
+ assert(volume <= 100);
+
+ if (volume >= 100)
+ return PCM_VOLUME_1;
+ else if (volume > 0)
+ return pcm_float_to_volume((exp(volume / 25.0) - 1) /
+ (54.5981500331F - 1));
+ else
+ return 0;
+}
+
+bool
+SoftwareMixer::SetVolume(unsigned new_volume, gcc_unused Error &error)
+{
+ assert(new_volume <= 100);
+
+ volume = new_volume;
+ volume_filter_set(filter, PercentVolumeToSoftwareVolume(new_volume));
+ return true;
+}
+
+const MixerPlugin software_mixer_plugin = {
+ software_mixer_init,
+ true,
+};
+
+inline Filter *
+SoftwareMixer::GetFilter()
+{
+ assert(owns_filter);
+
+ owns_filter = false;
+ return filter;
+}
+
+Filter *
+software_mixer_get_filter(Mixer *mixer)
+{
+ SoftwareMixer *sm = (SoftwareMixer *)mixer;
+ assert(sm->IsPlugin(software_mixer_plugin));
+ return sm->GetFilter();
+}