1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/*
* 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 "gerror.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);
};
#ifdef __cplusplus
extern "C" {
#endif
/**
* 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 occurring, 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 occurring, 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 occurring, 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 occurring, 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);
#ifdef __cplusplus
}
#endif
#endif
|
