146 lines
3.8 KiB
C
146 lines
3.8 KiB
C
/*
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* Copyright (C) 2003-2009 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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/** \file
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*
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* This header declares the filter_plugin class. It describes a
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* plugin API for objects which filter raw PCM data.
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*/
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#ifndef MPD_FILTER_PLUGIN_H
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#define MPD_FILTER_PLUGIN_H
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#include <glib.h>
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#include <stdbool.h>
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#include <stddef.h>
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struct config_param;
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struct filter;
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struct filter_plugin {
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const char *name;
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/**
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* Allocates and configures a filter.
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*/
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struct filter *(*init)(const struct config_param *param,
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GError **error_r);
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/**
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* Free instance data.
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*/
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void (*finish)(struct filter *filter);
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/**
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* Opens a filter.
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*/
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const struct audio_format *
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(*open)(struct filter *filter,
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const struct audio_format *audio_format,
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GError **error_r);
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/**
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* Closes a filter.
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*/
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void (*close)(struct filter *filter);
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/**
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* Filters a block of PCM data.
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*/
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const void *(*filter)(struct filter *filter,
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const void *src, size_t src_size,
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size_t *dest_buffer_r,
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GError **error_r);
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};
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/**
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* Creates a new instance of the specified filter plugin.
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*
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* @param plugin the filter plugin
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* @param param optional configuration section
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* @param error location to store the error occuring, or NULL to
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* ignore errors.
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* @return a new filter object, or NULL on error
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*/
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struct filter *
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filter_new(const struct filter_plugin *plugin,
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const struct config_param *param, GError **error_r);
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/**
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* Creates a new filter, loads configuration and the plugin name from
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* the specified configuration section.
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*
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* @param param the configuration section
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* @param error location to store the error occuring, or NULL to
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* ignore errors.
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* @return a new filter object, or NULL on error
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*/
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struct filter *
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filter_configured_new(const struct config_param *param, GError **error_r);
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/**
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* Deletes a filter. It must be closed prior to calling this
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* function, see filter_close().
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*
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* @param filter the filter object
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*/
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void
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filter_free(struct filter *filter);
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/**
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* Opens the filter, preparing it for filter_filter().
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*
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* @param filter the filter object
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* @param audio_format the audio format of incoming and outgoing data
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* @param error location to store the error occuring, or NULL to
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* ignore errors.
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* @return true on success, false on error
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*/
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const struct audio_format *
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filter_open(struct filter *filter, const struct audio_format *audio_format,
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GError **error_r);
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/**
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* Closes the filter. After that, you may call filter_open() again.
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*
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* @param filter the filter object
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*/
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void
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filter_close(struct filter *filter);
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/**
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* Filters a block of PCM data.
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*
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* @param filter the filter object
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* @param src the input buffer
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* @param src_size the size of #src_buffer in bytes
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* @param dest_size_r the size of the returned buffer
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* @param error location to store the error occuring, or NULL to
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* ignore errors.
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* @return the destination buffer on success (will be invalidated by
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* filter_close() or filter_filter()), NULL on error
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*/
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const void *
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filter_filter(struct filter *filter, const void *src, size_t src_size,
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size_t *dest_size_r,
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GError **error_r);
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#endif
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