mixer/software, filter/volume: convert to C++

src/filter/VolumeFilterPlugin.cxx

@@ -0,0 +1,159 @@
+/*
+ * 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 "filter_plugin.h"
+#include "filter_internal.h"
+#include "filter_registry.h"
+#include "conf.h"
+#include "pcm_buffer.h"
+#include "pcm_volume.h"
+#include "audio_format.h"
+
+#include <assert.h>
+#include <string.h>
+
+struct volume_filter {
+	struct filter filter;
+
+	/**
+	 * The current volume, from 0 to #PCM_VOLUME_1.
+	 */
+	unsigned volume;
+
+	struct audio_format audio_format;
+
+	struct pcm_buffer buffer;
+};
+
+static inline GQuark
+volume_quark(void)
+{
+	return g_quark_from_static_string("pcm_volume");
+}
+
+static struct filter *
+volume_filter_init(G_GNUC_UNUSED const struct config_param *param,
+		   G_GNUC_UNUSED GError **error_r)
+{
+	struct volume_filter *filter = g_new(struct volume_filter, 1);
+
+	filter_init(&filter->filter, &volume_filter_plugin);
+	filter->volume = PCM_VOLUME_1;
+
+	return &filter->filter;
+}
+
+static void
+volume_filter_finish(struct filter *filter)
+{
+	g_free(filter);
+}
+
+static const struct audio_format *
+volume_filter_open(struct filter *_filter, struct audio_format *audio_format,
+		   G_GNUC_UNUSED GError **error_r)
+{
+	struct volume_filter *filter = (struct volume_filter *)_filter;
+
+	filter->audio_format = *audio_format;
+	pcm_buffer_init(&filter->buffer);
+
+	return &filter->audio_format;
+}
+
+static void
+volume_filter_close(struct filter *_filter)
+{
+	struct volume_filter *filter = (struct volume_filter *)_filter;
+
+	pcm_buffer_deinit(&filter->buffer);
+}
+
+static const void *
+volume_filter_filter(struct filter *_filter, const void *src, size_t src_size,
+		     size_t *dest_size_r, GError **error_r)
+{
+	struct volume_filter *filter = (struct volume_filter *)_filter;
+	bool success;
+	void *dest;
+
+	*dest_size_r = src_size;
+
+	if (filter->volume >= PCM_VOLUME_1)
+		/* optimized special case: 100% volume = no-op */
+		return src;
+
+	dest = pcm_buffer_get(&filter->buffer, src_size);
+
+	if (filter->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);
+
+	success = pcm_volume(dest, src_size,
+			     sample_format(filter->audio_format.format),
+			     filter->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,
+	volume_filter_finish,
+	volume_filter_open,
+	volume_filter_close,
+	volume_filter_filter,
+};
+
+unsigned
+volume_filter_get(const struct filter *_filter)
+{
+	const struct volume_filter *filter =
+		(const struct volume_filter *)_filter;
+
+	assert(filter->filter.plugin == &volume_filter_plugin);
+	assert(filter->volume <= PCM_VOLUME_1);
+
+	return filter->volume;
+}
+
+void
+volume_filter_set(struct filter *_filter, unsigned volume)
+{
+	struct volume_filter *filter = (struct volume_filter *)_filter;
+
+	assert(filter->filter.plugin == &volume_filter_plugin);
+	assert(volume <= PCM_VOLUME_1);
+
+	filter->volume = volume;
+}
+