1 /***************************************************************************
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
10 * Copyright (C) 2007 Nicolas Pennequin
12 * All files in this archive are subject to the GNU General Public License.
13 * See the file COPYING in the source tree root for full license agreement.
15 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
16 * KIND, either express or implied.
18 ****************************************************************************/
23 #include <sys/types.h>
27 /* default point to start buffer refill */
28 #define AUDIO_DEFAULT_WATERMARK (1024*512)
29 /* amount of data to read in one read() call */
30 #define AUDIO_DEFAULT_FILECHUNK (1024*32)
31 /* point at which the file buffer will fight for CPU time */
32 #define AUDIO_FILEBUF_CRITICAL (1024*128)
33 /* amount of guess-space to allow for codecs that must hunt and peck
34 * for their correct seeek target, 32k seems a good size */
35 #define AUDIO_REBUFFER_GUESS_SIZE (1024*32)
50 /* Initialise the buffering subsystem */
51 bool buffering_init(char *buf
, size_t buflen
);
54 /***************************************************************************
55 * MAIN BUFFERING API CALLS
56 * ========================
58 * bufopen : Reserve space in the buffer for a given file
59 * bufalloc : Open a new handle from data that needs to be copied from memory
60 * bufclose : Close an open handle
61 * bufseek : Set handle reading index, relatively to the start of the file
62 * bufadvance: Move handle reading index, relatively to current position
63 * bufread : Copy data from a handle to a buffer
64 * bufgetdata: Obtain a pointer for linear access to a "size" amount of data
65 ****************************************************************************/
67 int bufopen(const char *file
, size_t offset
, enum data_type type
);
68 int bufalloc(const void *src
, size_t size
, enum data_type type
);
69 int bufclose(int handle_id
);
70 int bufseek(int handle_id
, size_t newpos
);
71 int bufadvance(int handle_id
, off_t offset
);
72 ssize_t
bufread(int handle_id
, size_t size
, void *dest
);
73 ssize_t
bufgetdata(int handle_id
, size_t size
, void **data
);
76 /***************************************************************************
80 * buf_get_offset: Get a handle offset from a pointer
81 * buf_handle_offset: Get the offset of the first buffered byte from the file
82 * buf_request_buffer_handle: Request buffering of a handle
83 * buf_set_base_handle: Tell the buffering thread which handle is currently read
84 * buf_used: Total amount of buffer space used (including allocated space)
85 ****************************************************************************/
87 ssize_t
buf_get_offset(int handle_id
, void *ptr
);
88 ssize_t
buf_handle_offset(int handle_id
);
89 void buf_request_buffer_handle(int handle_id
);
90 void buf_set_base_handle(int handle_id
);
91 size_t buf_used(void);
94 /***************************************************************************
98 * register_buffer_low_callback, unregister_buffer_low_callback:
100 * Register/Unregister callback functions that will get executed when the buffer
101 * goes below the low watermark. They are executed once, then forgotten.
103 * NOTE: The callbacks are called from the buffering thread, so don't make them
104 * do too much. Ideally they should just post an event to a queue and return.
105 ****************************************************************************/
107 #define MAX_BUF_CALLBACKS 4
108 typedef void (*buffer_low_callback
)(void);
109 bool register_buffer_low_callback(buffer_low_callback func
);
110 void unregister_buffer_low_callback(buffer_low_callback func
);
114 struct buffering_debug
{
116 size_t buffered_data
;
121 void buffering_get_debugdata(struct buffering_debug
*dbgdata
);