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Diffstat (limited to 'src/filter_plugin.h')
-rw-r--r-- | src/filter_plugin.h | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/filter_plugin.h b/src/filter_plugin.h new file mode 100644 index 000000000..cec15794f --- /dev/null +++ b/src/filter_plugin.h @@ -0,0 +1,150 @@ +/* + * 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 + * + * This header declares the filter_plugin class. It describes a + * plugin API for objects which filter raw PCM data. + */ + +#ifndef MPD_FILTER_PLUGIN_H +#define MPD_FILTER_PLUGIN_H + +#include <glib.h> + +#include <stdbool.h> +#include <stddef.h> + +struct config_param; +struct filter; + +struct filter_plugin { + const char *name; + + /** + * Allocates and configures a filter. + */ + struct filter *(*init)(const struct config_param *param, + GError **error_r); + + /** + * Free instance data. + */ + void (*finish)(struct filter *filter); + + /** + * Opens a filter. + * + * @param audio_format the audio format of incoming data; the + * plugin may modify the object to enforce another input + * format + */ + const struct audio_format * + (*open)(struct filter *filter, + struct audio_format *audio_format, + GError **error_r); + + /** + * Closes a filter. + */ + void (*close)(struct filter *filter); + + /** + * Filters a block of PCM data. + */ + const void *(*filter)(struct filter *filter, + const void *src, size_t src_size, + size_t *dest_buffer_r, + GError **error_r); +}; + +/** + * Creates a new instance of the specified filter plugin. + * + * @param plugin the filter plugin + * @param param optional configuration section + * @param error location to store the error occuring, or NULL to + * ignore errors. + * @return a new filter object, or NULL on error + */ +struct filter * +filter_new(const struct filter_plugin *plugin, + const struct config_param *param, GError **error_r); + +/** + * Creates a new filter, loads configuration and the plugin name from + * the specified configuration section. + * + * @param param the configuration section + * @param error location to store the error occuring, or NULL to + * ignore errors. + * @return a new filter object, or NULL on error + */ +struct filter * +filter_configured_new(const struct config_param *param, GError **error_r); + +/** + * Deletes a filter. It must be closed prior to calling this + * function, see filter_close(). + * + * @param filter the filter object + */ +void +filter_free(struct filter *filter); + +/** + * Opens the filter, preparing it for filter_filter(). + * + * @param filter the filter object + * @param audio_format the audio format of incoming data; the plugin + * may modify the object to enforce another input format + * @param error location to store the error occuring, or NULL to + * ignore errors. + * @return the format of outgoing data + */ +const struct audio_format * +filter_open(struct filter *filter, struct audio_format *audio_format, + GError **error_r); + +/** + * Closes the filter. After that, you may call filter_open() again. + * + * @param filter the filter object + */ +void +filter_close(struct filter *filter); + +/** + * Filters a block of PCM data. + * + * @param filter the filter object + * @param src the input buffer + * @param src_size the size of #src_buffer in bytes + * @param dest_size_r the size of the returned buffer + * @param error location to store the error occuring, or NULL to + * ignore errors. + * @return the destination buffer on success (will be invalidated by + * filter_close() or filter_filter()), NULL on error + */ +const void * +filter_filter(struct filter *filter, const void *src, size_t src_size, + size_t *dest_size_r, + GError **error_r); + +#endif |