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/*
* File : lf_ring_buffer.h
* Author : Jérémy Zurcher <jeremy@asynk.ch>
* Date : 05/01/010
* License :
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#ifndef _LF_RING_BUFFER_H_
#define _LF_RING_BUFFER_H_
# ifdef __cplusplus
extern "C" {
# endif /* __cplusplus */
#define BACKOFF_DELAY_INIT 1000
#define BACKOFF_DELAY_INC 3000
#define BACKOFF_DELAY_MAX 90000
#define NO_BLOCK 1 /* if buffer is full, leave instead of try again and again */
#define IS_NOT_BLOCKING( flags ) ( (flags)&NO_BLOCK )
#define RB_DATA_SIZE 63
typedef char rb_data_t;
typedef struct buffer_el {
char status;
rb_data_t data[RB_DATA_SIZE];
} lf_buffer_el_t;
typedef struct ring_buffer {
lf_buffer_el_t *buffer; /* buffer data */
int n_buf; /* number of buffers */
int read_from; /* index where to read data from */
int write_to; /* index where to write data to */
int write_delay; /* backoff nanosleep to reduce fast looping when writing */
int read_delay; /* backoff nanosleep to reduce fast looping when reading */
} lf_ring_buffer_t;
#define IS_AVAILABLE( idx ) (r->buffer[(idx)].status==0)
#define MARK_AS_FILLED( idx ) { r->buffer[(idx)].status=1; }
#define MARK_AS_READ( idx ) { r->buffer[(idx)].status=0; }
/* initialize an empty lf_ring_buffer struct */
lf_ring_buffer_t* lf_ring_buffer_create( int n_buf );
/* destroy an lf_ring_buffer strcture */
void lf_ring_buffer_destroy( lf_ring_buffer_t *r );
/* write data into the ring buffer
* return 0 on success
* return -1 if IS_NOT_BLOCKING and buffer is full
*/
int lf_ring_buffer_write( lf_ring_buffer_t *r, rb_data_t *data, int flags );
/* read data from the ring buffer
* return 0 on success
* return -1 if IS_NOT_BLOCKING and buffer is empty
*/
int lf_ring_buffer_read( lf_ring_buffer_t *r, rb_data_t *data, int flags );
# ifdef __cplusplus
}
# endif /* __cplusplus */
# endif /* _LF_RING_BUFFER_H_ */
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