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authorMax Kellermann <max@duempel.org>2009-07-06 10:01:02 +0200
committerMax Kellermann <max@duempel.org>2009-07-06 10:01:02 +0200
commitc372c3756b24d2ecd879f1f857ccdbf421f3be33 (patch)
tree7ec01196501c63e7d29a236c2a588c897cee305f
parent78fa3f06f9fadcc274c0a0042d28d59c88bff152 (diff)
downloadmpd-c372c3756b24d2ecd879f1f857ccdbf421f3be33.tar.gz
mpd-c372c3756b24d2ecd879f1f857ccdbf421f3be33.tar.xz
mpd-c372c3756b24d2ecd879f1f857ccdbf421f3be33.zip
filter/chain: new library for creating a chain of filters
-rw-r--r--Makefile.am2
-rw-r--r--src/filter/chain_filter_plugin.c177
-rw-r--r--src/filter/chain_filter_plugin.h48
-rw-r--r--src/filter_registry.c1
-rw-r--r--src/filter_registry.h1
5 files changed, 229 insertions, 0 deletions
diff --git a/Makefile.am b/Makefile.am
index 3d16ca77d..156c1c2da 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -45,6 +45,7 @@ mpd_headers = \
src/filter_internal.h \
src/filter_plugin.h \
src/filter_registry.h \
+ src/filter/chain_filter_plugin.h \
src/filter/volume_filter_plugin.h \
src/buffer2array.h \
src/command.h \
@@ -583,6 +584,7 @@ endif
FILTER_SRC = \
src/filter/null_filter_plugin.c \
+ src/filter/chain_filter_plugin.c \
src/filter/volume_filter_plugin.c
diff --git a/src/filter/chain_filter_plugin.c b/src/filter/chain_filter_plugin.c
new file mode 100644
index 000000000..ec8bef5c0
--- /dev/null
+++ b/src/filter/chain_filter_plugin.c
@@ -0,0 +1,177 @@
+/*
+ * 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/chain_filter_plugin.h"
+#include "filter_plugin.h"
+#include "filter_internal.h"
+#include "filter_registry.h"
+
+#include <assert.h>
+
+struct filter_chain {
+ /** the base class */
+ struct filter base;
+
+ GSList *children;
+};
+
+static struct filter *
+chain_filter_init(G_GNUC_UNUSED const struct config_param *param,
+ G_GNUC_UNUSED GError **error_r)
+{
+ struct filter_chain *chain = g_new(struct filter_chain, 1);
+
+ filter_init(&chain->base, &chain_filter_plugin);
+ chain->children = NULL;
+
+ return &chain->base;
+}
+
+static void
+chain_free_child(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+ struct filter *filter = data;
+
+ filter_free(filter);
+}
+
+static void
+chain_filter_finish(struct filter *_filter)
+{
+ struct filter_chain *chain = (struct filter_chain *)_filter;
+
+ g_slist_foreach(chain->children, chain_free_child, NULL);
+ g_slist_free(chain->children);
+
+ g_free(chain);
+}
+
+/**
+ * Close all filters in the chain until #until is reached. #until
+ * itself is not closed.
+ */
+static void
+chain_close_until(struct filter_chain *chain, const struct filter *until)
+{
+ GSList *i = chain->children;
+ struct filter *filter;
+
+ while (true) {
+ /* this assertion fails if #until does not exist
+ (anymore) */
+ assert(i != NULL);
+
+ if (i->data == until)
+ /* don't close this filter */
+ break;
+
+ /* close this filter */
+ filter = i->data;
+ filter_close(filter);
+
+ i = g_slist_next(i);
+ }
+}
+
+static const struct audio_format *
+chain_filter_open(struct filter *_filter,
+ const struct audio_format *audio_format,
+ GError **error_r)
+{
+ struct filter_chain *chain = (struct filter_chain *)_filter;
+
+ for (GSList *i = chain->children; i != NULL; i = g_slist_next(i)) {
+ struct filter *filter = i->data;
+
+ audio_format = filter_open(filter, audio_format, error_r);
+ if (audio_format == NULL) {
+ /* rollback, close all children */
+ chain_close_until(chain, filter);
+ return NULL;
+ }
+ }
+
+ /* return the output format of the last filter */
+ return audio_format;
+}
+
+static void
+chain_close_child(gpointer data, G_GNUC_UNUSED gpointer user_data)
+{
+ struct filter *filter = data;
+
+ filter_close(filter);
+}
+
+static void
+chain_filter_close(struct filter *_filter)
+{
+ struct filter_chain *chain = (struct filter_chain *)_filter;
+
+ g_slist_foreach(chain->children, chain_close_child, NULL);
+}
+
+static const void *
+chain_filter_filter(struct filter *_filter,
+ const void *src, size_t src_size,
+ size_t *dest_size_r, GError **error_r)
+{
+ struct filter_chain *chain = (struct filter_chain *)_filter;
+
+ for (GSList *i = chain->children; i != NULL; i = g_slist_next(i)) {
+ struct filter *filter = i->data;
+
+ /* feed the output of the previous filter as input
+ into the current one */
+ src = filter_filter(filter, src, src_size, &src_size, error_r);
+ if (src == NULL)
+ chain_close_until(chain, filter);
+ }
+
+ /* return the output of the last filter */
+ *dest_size_r = src_size;
+ return src;
+}
+
+const struct filter_plugin chain_filter_plugin = {
+ .name = "chain",
+ .init = chain_filter_init,
+ .finish = chain_filter_finish,
+ .open = chain_filter_open,
+ .close = chain_filter_close,
+ .filter = chain_filter_filter,
+};
+
+struct filter *
+filter_chain_new(void)
+{
+ struct filter *filter = filter_new(&chain_filter_plugin, NULL, NULL);
+ /* chain_filter_init() never fails */
+ assert(filter != NULL);
+
+ return filter;
+}
+
+void
+filter_chain_append(struct filter *_chain, struct filter *filter)
+{
+ struct filter_chain *chain = (struct filter_chain *)_chain;
+
+ chain->children = g_slist_append(chain->children, filter);
+}
diff --git a/src/filter/chain_filter_plugin.h b/src/filter/chain_filter_plugin.h
new file mode 100644
index 000000000..f8462b22d
--- /dev/null
+++ b/src/filter/chain_filter_plugin.h
@@ -0,0 +1,48 @@
+/*
+ * 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.
+ */
+
+/** \file
+ *
+ * A filter chain is a container for several filters. They are
+ * chained together, i.e. called in a row, one filter passing its
+ * output to the next one.
+ */
+
+#ifndef MPD_FILTER_CHAIN_H
+#define MPD_FILTER_CHAIN_H
+
+struct filter;
+
+/**
+ * Creates a new filter chain.
+ */
+struct filter *
+filter_chain_new(void);
+
+/**
+ * Appends a new filter at the end of the filter chain. You must call
+ * this function before the first filter_open() call.
+ *
+ * @param chain the filter chain created with filter_chain_new()
+ * @param filter the filter to be appended to #chain
+ */
+void
+filter_chain_append(struct filter *chain, struct filter *filter);
+
+#endif
diff --git a/src/filter_registry.c b/src/filter_registry.c
index db47ab7df..c8887aabf 100644
--- a/src/filter_registry.c
+++ b/src/filter_registry.c
@@ -25,6 +25,7 @@
const struct filter_plugin *const filter_plugins[] = {
&null_filter_plugin,
+ &chain_filter_plugin,
&volume_filter_plugin,
NULL,
};
diff --git a/src/filter_registry.h b/src/filter_registry.h
index af873316e..0eb4b8f03 100644
--- a/src/filter_registry.h
+++ b/src/filter_registry.h
@@ -27,6 +27,7 @@
#define MPD_FILTER_REGISTRY_H
extern const struct filter_plugin null_filter_plugin;
+extern const struct filter_plugin chain_filter_plugin;
extern const struct filter_plugin volume_filter_plugin;
const struct filter_plugin *