1 files changed, 111 insertions, 0 deletions
diff --git a/src/mixer/SoftwareMixerPlugin.cxx b/src/mixer/SoftwareMixerPlugin.cxx
new file mode 100644
index 000000000..6c287ea07
--- /dev/null
+++ b/src/mixer/SoftwareMixerPlugin.cxx
@@ -0,0 +1,111 @@
+/*
+ * 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 "SoftwareMixerPlugin.hxx"
+#include "MixerInternal.hxx"
+#include "FilterPlugin.hxx"
+#include "FilterRegistry.hxx"
+#include "filter/VolumeFilterPlugin.hxx"
+#include "PcmVolume.hxx"
+
+#include <assert.h>
+#include <math.h>
+
+struct software_mixer {
+	/** the base mixer class */
+	struct mixer base;
+
+	Filter *filter;
+
+	unsigned volume;
+};
+
+static struct mixer *
+software_mixer_init(G_GNUC_UNUSED void *ao,
+		    G_GNUC_UNUSED const struct config_param *param,
+		    G_GNUC_UNUSED GError **error_r)
+{
+	struct software_mixer *sm = g_new(struct software_mixer, 1);
+
+	mixer_init(&sm->base, &software_mixer_plugin);
+
+	sm->filter = filter_new(&volume_filter_plugin, NULL, NULL);
+	assert(sm->filter != NULL);
+
+	sm->volume = 100;
+
+	return &sm->base;
+}
+
+static void
+software_mixer_finish(struct mixer *data)
+{
+	struct software_mixer *sm = (struct software_mixer *)data;
+
+	g_free(sm);
+}
+
+static int
+software_mixer_get_volume(struct mixer *mixer, G_GNUC_UNUSED GError **error_r)
+{
+	struct software_mixer *sm = (struct software_mixer *)mixer;
+
+	return sm->volume;
+}
+
+static bool
+software_mixer_set_volume(struct mixer *mixer, unsigned volume,
+			  G_GNUC_UNUSED GError **error_r)
+{
+	struct software_mixer *sm = (struct software_mixer *)mixer;
+
+	assert(volume <= 100);
+
+	sm->volume = volume;
+
+	if (volume >= 100)
+		volume = PCM_VOLUME_1;
+	else if (volume > 0)
+		volume = pcm_float_to_volume((exp(volume / 25.0) - 1) /
+					     (54.5981500331F - 1));
+
+	volume_filter_set(sm->filter, volume);
+	return true;
+}
+
+const struct mixer_plugin software_mixer_plugin = {
+	software_mixer_init,
+	software_mixer_finish,
+	nullptr,
+	nullptr,
+	software_mixer_get_volume,
+	software_mixer_set_volume,
+	true,
+};
+
+Filter *
+software_mixer_get_filter(struct mixer *mixer)
+{
+	struct software_mixer *sm = (struct software_mixer *)mixer;
+
+	assert(sm->base.plugin == &software_mixer_plugin);
+
+	return sm->filter;
+}