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/*
* Copyright (C) 2003-2011 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
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