rgbyteclock-code/ringbuffer.c

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <struppi@struppi.name> wrote this file. As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.
 * (c) 2008-2014 Stefan Rupp
 * ----------------------------------------------------------------------------
 */
 



#include <stdlib.h>
#include <inttypes.h>

#include <util/atomic.h>

#include "ringbuffer.h"


void ringbuf_init(void *ringbuffer, uint8_t rb_size, void (*idle_func)(void))
{
  ringbuffer_t *rb = (ringbuffer_t *) ringbuffer;

  rb->size = rb_size;
  rb->free = rb_size;
  rb->write_idx = 0;
  rb->read_idx = 0;
  rb->idle_func = idle_func;
  return;
}


int8_t ringbuf_get_nb(void *ringbuffer, uint8_t *ch)
{
  ringbuffer_t *rb = (ringbuffer_t *) ringbuffer;
  if ( rb->size - rb->free == 0) {
    *ch = 0xff;
    return 0;
  }
  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
    rb->free++;
    *ch = rb->buffer[rb->read_idx++];
    if ( rb->read_idx >= rb->size ) {
      rb->read_idx = 0;
    }
  }
  return 1;
}


int8_t ringbuf_get(void *ringbuffer, uint8_t *ch)
{
  ringbuffer_t *rb = (ringbuffer_t *) ringbuffer;
  while ( rb->size - rb->free == 0) {
    if (rb->idle_func != NULL) {
      rb->idle_func();
    }
  }
  rb->free++;
  *ch = rb->buffer[rb->read_idx++];
  if ( rb->read_idx >= rb->size ) {
    rb->read_idx = 0;
  }
  return 1;
}


int8_t ringbuf_put_nb(void * ringbuffer, uint8_t ch)
{
  ringbuffer_t *rb = (ringbuffer_t *) ringbuffer;

  if (rb->free > 0) {
    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
      rb->free--;
      rb->buffer[rb->write_idx++] = ch;
      if (rb->write_idx >= rb->size) {
        rb->write_idx = 0;
      }
    }
    return 1;
  }
  return 0;
}



int8_t ringbuf_get_num_waiting( void * ringbuffer)
{
  ringbuffer_t *rb = (ringbuffer_t *) ringbuffer;
  uint8_t waiting;
  
  waiting = rb->size - rb->free;
  
  return waiting;
}