ringbuffer.c

#include "ringbuffer.h"
#include "mculibrary.h"
#include "string.h"
// dummy - may be dynamic in future
static uint16_t bufsize(struct ringbuffer *r) {
  return 1023;
}
 
void ringbuffer_add_byte(struct ringbuffer *r, uint8_t b) {
  uint16_t size = bufsize(r);
 
  if (r->writeptr >= size) {
    r->writeptr = 0;
  }
  r->buf[r->writeptr] = b;
  r->writeptr++;
  r->bytes++;
}
uint16_t ringbuffer_get_byte(struct ringbuffer *r) {
  uint16_t size = bufsize(r);
 
  if (r->readptr >= size) {
    r->readptr = 0;
  }
  if (r->bytes == 0) {
    return 500;
  }
  uint8_t res = r->buf[r->readptr];
 
  r->readptr++;
  uint16_t foo = (uint16_t)res;
 
  mculib_disable_irq(2);
  r->bytes--;
  mculib_enable_irq(2);
  return foo & 0xFF;
}
 
 
void ringbuffer_init(struct ringbuffer *r) {
  memset(r, 0, sizeof(struct ringbuffer));
}
 
// return number of characters (-2 == delimiter not found, -1 buf too small
// TODO: it seems to consume more bytes than available and leave the readptr somewhat borken
int ringbuffer_get_to_delimiter(struct ringbuffer *r, char delimiter, char *outbuf, int outbufsize) {
  uint16_t size = bufsize(r);
  uint16_t readptr = r->readptr;
  uint32_t bytes = r->bytes;
  uint16_t linelen = 0;
 
repeat:
  if (readptr >= size) {
    readptr = 0;
  }
 
  if (bytes == 0) {
    return -2;
  }
  uint8_t res = r->buf[readptr];
 
  // a "line" is somewhat ill defined. can be \n, \r, or \r\n
  if ((res == delimiter) || (delimiter == '\r' && res == '\n') || (delimiter == '\n' && res == '\r')) {
    readptr++; // consume the delimeter
    if (readptr >= size) {
      readptr = 0;
    }
    bytes--;
    // also "consume" the bytes!
    mculib_disable_irq(2);
    r->bytes = r->bytes - linelen;
    r->readptr = readptr;
    mculib_enable_irq(2);
 
    return linelen;
  }
  readptr++;
  bytes--;
  outbuf[linelen++] = res;
  outbuf[linelen] = 0;
  if (linelen >= outbufsize) {
    return -1;
  }
  goto repeat;
}