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/*
* ringbuf.h
*
* This file provides simple ring buffer functionality.
*
* $Id$
*/
#ifndef __RINGBUF_H__
#define __RINGBUF_H__
#ifndef RINGBUF_QUEUE_LENGTH
#define RINGBUF_QUEUE_LENGTH 128
#endif
typedef struct {
char buffer[RINGBUF_QUEUE_LENGTH];
volatile int head;
volatile int tail;
} Ring_buffer_t;
#define Ring_buffer_Initialize( _buffer ) \
do { \
(_buffer)->head = (_buffer)->tail = 0; \
} while ( 0 )
#define Ring_buffer_Is_empty( _buffer ) \
( (_buffer)->head == (_buffer)->tail )
#define Ring_buffer_Is_full( _buffer ) \
( (_buffer)->head == ((_buffer)->tail + 1) % RINGBUF_QUEUE_LENGTH )
#define Ring_buffer_Add_character( _buffer, _ch ) \
do { \
rtems_unsigned32 isrlevel; \
\
rtems_interrupt_disable( isrlevel ); \
(_buffer)->tail = ((_buffer)->tail+1) % RINGBUF_QUEUE_LENGTH; \
(_buffer)->buffer[ (_buffer)->tail ] = (_ch); \
rtems_interrupt_enable( isrlevel ); \
} while ( 0 )
#define Ring_buffer_Remove_character( _buffer, _ch ) \
do { \
rtems_unsigned32 isrlevel; \
\
rtems_interrupt_disable( isrlevel ); \
(_buffer)->head = ((_buffer)->head+1) % RINGBUF_QUEUE_LENGTH; \
(_ch) = (_buffer)->buffer[ (_buffer)->head ]; \
rtems_interrupt_enable( isrlevel ); \
} while ( 0 )
#endif
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