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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 Nicolas Pennequin
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef _BUFFERING_H_
#define _BUFFERING_H_
#include <sys/types.h>
#include <stdbool.h>
enum data_type {
TYPE_CODEC,
TYPE_PACKET_AUDIO,
TYPE_ATOMIC_AUDIO,
TYPE_ID3,
TYPE_CUESHEET,
TYPE_IMAGE,
TYPE_BUFFER,
TYPE_UNKNOWN,
};
/* Error return values */
#define ERR_HANDLE_NOT_FOUND -1
#define ERR_BUFFER_FULL -2
#define ERR_INVALID_VALUE -3
#define ERR_FILE_ERROR -4
/* Initialise the buffering subsystem */
void buffering_init(void);
/* Reset the buffering system */
bool buffering_reset(char *buf, size_t buflen);
/***************************************************************************
* MAIN BUFFERING API CALLS
* ========================
*
* bufopen : Reserve space in the buffer for a given file
* bufalloc : Open a new handle from data that needs to be copied from memory
* bufclose : Close an open handle
* bufseek : Set handle reading index, relatively to the start of the file
* bufadvance: Move handle reading index, relatively to current position
* bufread : Copy data from a handle to a buffer
* bufgetdata: Obtain a pointer for linear access to a "size" amount of data
*
* NOTE: bufread and bufgetdata will block the caller until the requested
* amount of data is ready (unless EOF is reached).
****************************************************************************/
#define BUF_MAX_HANDLES 256
int bufopen(const char *file, size_t offset, enum data_type type);
int bufalloc(const void *src, size_t size, enum data_type type);
bool bufclose(int handle_id);
int bufseek(int handle_id, size_t newpos);
int bufadvance(int handle_id, off_t offset);
ssize_t bufread(int handle_id, size_t size, void *dest);
ssize_t bufgetdata(int handle_id, size_t size, void **data);
/***************************************************************************
* SECONDARY FUNCTIONS
* ===================
*
* buf_get_offset: Get a handle offset from a pointer
* buf_handle_offset: Get the offset of the first buffered byte from the file
* buf_request_buffer_handle: Request buffering of a handle
* buf_set_base_handle: Tell the buffering thread which handle is currently read
* buf_used: Total amount of buffer space used (including allocated space)
****************************************************************************/
ssize_t buf_get_offset(int handle_id, void *ptr);
ssize_t buf_handle_offset(int handle_id);
void buf_request_buffer_handle(int handle_id);
void buf_set_base_handle(int handle_id);
size_t buf_used(void);
/***************************************************************************
* CALLBACK UTILITIES
* ==================
*
* register_buffer_low_callback, unregister_buffer_low_callback:
*
* Register/Unregister callback functions that will get executed when the buffer
* goes below the low watermark. They are executed once, then forgotten.
*
* NOTE: The callbacks are called from the buffering thread, so don't make them
* do too much. Ideally they should just post an event to a queue and return.
****************************************************************************/
#define MAX_BUF_CALLBACKS 4
typedef void (*buffer_low_callback)(void);
bool register_buffer_low_callback(buffer_low_callback func);
void unregister_buffer_low_callback(buffer_low_callback func);
/* Settings */
enum {
BUFFERING_SET_WATERMARK = 1,
BUFFERING_SET_CHUNKSIZE,
};
void buf_set_watermark(size_t bytes);
/* Debugging */
struct buffering_debug {
int num_handles;
size_t buffered_data;
size_t wasted_space;
size_t data_rem;
size_t useful_data;
};
void buffering_get_debugdata(struct buffering_debug *dbgdata);
#endif
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