/* Ringpuffer */
/* Datei: ringbufr.c */

#include <stdio.h>
#include <stdlib.h>
#include "ringbufr.h"

int ringpuffer_init (ringpuffer * rp, int size)
{
if (size < 0) return EOF;
rp->puffer = (char *) malloc (size);
rp->laenge = size;
rp->leseindex = 0;
rp->schreibindex = 0;
return 0;
};
void ringpuffer_kill (ringpuffer * rp)
{
free (rp->puffer);
};
int ringpuffer_get (ringpuffer * rp)
{
int zwi;
if (rp->belegt > 0)
  {
  rp->belegt--;
  zwi = rp->puffer[rp->leseindex++];
  if (rp->leseindex >= rp->laenge)
     rp->leseindex = 0;
  return zwi;
  }
else
  return EOF;
}
int ringpuffer_put(ringpuffer *rp,int wert)
{
if (rp->belegt < rp->laenge)
  {
  rp->belegt++;
  rp->puffer[rp->schreibindex++] = wert;
  if (rp->schreibindex >= rp->laenge)
     rp->schreibindex = 0;
  return wert;
  }
else
  return EOF;
}
void ringpuffer_clear (ringpuffer * rp)
{
rp->leseindex = 0;
rp->schreibindex = 0;
rp->belegt = 0;
}