filter/convert: new filter which calls pcm_convert() on demand

src/filter/convert_filter_plugin.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2003-2009 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 "filter/convert_filter_plugin.h"
+#include "filter_plugin.h"
+#include "filter_internal.h"
+#include "filter_registry.h"
+#include "conf.h"
+#include "pcm_convert.h"
+#include "audio_format.h"
+#include "poison.h"
+
+#include <assert.h>
+#include <string.h>
+
+struct convert_filter {
+	struct filter base;
+
+	/**
+	 * The current convert, from 0 to #PCM_CONVERT_1.
+	 */
+	unsigned convert;
+
+	/**
+	 * The input audio format; PCM data is passed to the filter()
+	 * method in this format.
+	 */
+	struct audio_format in_audio_format;
+
+	/**
+	 * The output audio format; the consumer of this plugin
+	 * expects PCM data in this format.  This defaults to
+	 * #in_audio_format, and can be set with convert_filter_set().
+	 */
+	struct audio_format out_audio_format;
+
+	struct pcm_convert_state state;
+};
+
+static inline GQuark
+convert_quark(void)
+{
+	return g_quark_from_static_string("pcm_convert");
+}
+
+static struct filter *
+convert_filter_init(G_GNUC_UNUSED const struct config_param *param,
+		    G_GNUC_UNUSED GError **error_r)
+{
+	struct convert_filter *filter = g_new(struct convert_filter, 1);
+
+	filter_init(&filter->base, &convert_filter_plugin);
+	return &filter->base;
+}
+
+static void
+convert_filter_finish(struct filter *filter)
+{
+	g_free(filter);
+}
+
+static const struct audio_format *
+convert_filter_open(struct filter *_filter,
+		    const struct audio_format *audio_format,
+		    G_GNUC_UNUSED GError **error_r)
+{
+	struct convert_filter *filter = (struct convert_filter *)_filter;
+
+	assert(audio_format_valid(audio_format));
+
+	filter->in_audio_format = filter->out_audio_format = *audio_format;
+	pcm_convert_init(&filter->state);
+
+	return audio_format;
+}
+
+static void
+convert_filter_close(struct filter *_filter)
+{
+	struct convert_filter *filter = (struct convert_filter *)_filter;
+
+	pcm_convert_deinit(&filter->state);
+
+	poison_undefined(&filter->in_audio_format,
+			 sizeof(filter->in_audio_format));
+	poison_undefined(&filter->out_audio_format,
+			 sizeof(filter->out_audio_format));
+}
+
+static const void *
+convert_filter_filter(struct filter *_filter, const void *src, size_t src_size,
+		     size_t *dest_size_r, GError **error_r)
+{
+	struct convert_filter *filter = (struct convert_filter *)_filter;
+	const void *dest;
+
+	if (audio_format_equals(&filter->in_audio_format,
+				&filter->out_audio_format)) {
+		/* optimized special case: no-op */
+		*dest_size_r = src_size;
+		return src;
+	}
+
+	dest = pcm_convert(&filter->state, &filter->in_audio_format,
+			   src, src_size,
+			   &filter->out_audio_format, dest_size_r);
+	if (dest == NULL) {
+		g_set_error(error_r, convert_quark(), 0,
+			    "pcm_convert() has failed");
+		return NULL;
+	}
+
+	return dest;
+}
+
+const struct filter_plugin convert_filter_plugin = {
+	.name = "convert",
+	.init = convert_filter_init,
+	.finish = convert_filter_finish,
+	.open = convert_filter_open,
+	.close = convert_filter_close,
+	.filter = convert_filter_filter,
+};
+
+void
+convert_filter_set(struct filter *_filter,
+		   const struct audio_format *out_audio_format)
+{
+	struct convert_filter *filter = (struct convert_filter *)_filter;
+
+	assert(filter != NULL);
+	assert(audio_format_valid(&filter->in_audio_format));
+	assert(audio_format_valid(&filter->out_audio_format));
+	assert(out_audio_format != NULL);
+	assert(audio_format_valid(out_audio_format));
+
+	filter->out_audio_format = *out_audio_format;
+}

src/filter/convert_filter_plugin.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2003-2009 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.
+ */
+
+#ifndef CONVERT_FILTER_PLUGIN_H
+#define CONVERT_FILTER_PLUGIN_H
+
+struct filter;
+struct audio_format;
+
+/**
+ * Sets the output audio format for the specified filter.  You must
+ * call this after the filter has been opened.  Since this audio
+ * format switch is a violation of the filter API, this filter must be
+ * the last in a chain.
+ */
+void
+convert_filter_set(struct filter *filter,
+		   const struct audio_format *out_audio_format);
+
+#endif