1 files changed, 124 insertions, 0 deletions
diff --git a/src/mixer/Volume.cxx b/src/mixer/Volume.cxx
new file mode 100644
index 000000000..abb01fb40
--- /dev/null
+++ b/src/mixer/Volume.cxx
@@ -0,0 +1,124 @@
+/*
+ * 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 "Volume.hxx"
+#include "output/MultipleOutputs.hxx"
+#include "Idle.hxx"
+#include "util/StringUtil.hxx"
+#include "util/Domain.hxx"
+#include "system/PeriodClock.hxx"
+#include "fs/io/BufferedOutputStream.hxx"
+#include "Log.hxx"
+
+#include <assert.h>
+#include <stdlib.h>
+
+#define SW_VOLUME_STATE                         "sw_volume: "
+
+static constexpr Domain volume_domain("volume");
+
+static unsigned volume_software_set = 100;
+
+/** the cached hardware mixer value; invalid if negative */
+static int last_hardware_volume = -1;
+/** the age of #last_hardware_volume */
+static PeriodClock hardware_volume_clock;
+
+void
+InvalidateHardwareVolume()
+{
+	/* flush the hardware volume cache */
+	last_hardware_volume = -1;
+}
+
+int
+volume_level_get(const MultipleOutputs &outputs)
+{
+	if (last_hardware_volume >= 0 &&
+	    !hardware_volume_clock.CheckUpdate(1000))
+		/* throttle access to hardware mixers */
+		return last_hardware_volume;
+
+	last_hardware_volume = outputs.GetVolume();
+	return last_hardware_volume;
+}
+
+static bool
+software_volume_change(MultipleOutputs &outputs, unsigned volume)
+{
+	assert(volume <= 100);
+
+	volume_software_set = volume;
+	outputs.SetSoftwareVolume(volume);
+
+	return true;
+}
+
+static bool
+hardware_volume_change(MultipleOutputs &outputs, unsigned volume)
+{
+	/* reset the cache */
+	last_hardware_volume = -1;
+
+	return outputs.SetVolume(volume);
+}
+
+bool
+volume_level_change(MultipleOutputs &outputs, unsigned volume)
+{
+	assert(volume <= 100);
+
+	volume_software_set = volume;
+
+	idle_add(IDLE_MIXER);
+
+	return hardware_volume_change(outputs, volume);
+}
+
+bool
+read_sw_volume_state(const char *line, MultipleOutputs &outputs)
+{
+	char *end = nullptr;
+	long int sv;
+
+	if (!StringStartsWith(line, SW_VOLUME_STATE))
+		return false;
+
+	line += sizeof(SW_VOLUME_STATE) - 1;
+	sv = strtol(line, &end, 10);
+	if (*end == 0 && sv >= 0 && sv <= 100)
+		software_volume_change(outputs, sv);
+	else
+		FormatWarning(volume_domain,
+			      "Can't parse software volume: %s", line);
+	return true;
+}
+
+void
+save_sw_volume_state(BufferedOutputStream &os)
+{
+	os.Format(SW_VOLUME_STATE "%u\n", volume_software_set);
+}
+
+unsigned
+sw_volume_state_get_hash(void)
+{
+	return volume_software_set;
+}