nmea_hl.h File Reference

interface to NMEA parser More...

#include <stdint.h>
#include "gps-parser.h"

Go to the source code of this file.

Data Structures
struct	proto_nmea_parser_s
Defines
#define	NMEA_BUFLEN   (122)
	size of parser input buffer, including trailing ''
Typedefs
typedef struct proto_nmea_parser_s	proto_nmea_parser_t
Functions
gps_line_status_t	nmea_recvd (gps_parser_t *, usart_rxdata_t)
	give one character to NMEA parser

---

Detailed Description

interface to NMEA parser

---

Function Documentation

gps_line_status_t nmea_recvd	(	gps_parser_t *	,
		usart_rxdata_t
	)

give one character to NMEA parser

Returns:

information about last received line (if any)

{
  gps_parser_t * p = parser; /* for shorter source code */
  proto_nmea_parser_t * pp = (proto_nmea_parser_t*)parser->proto_parser;
  gps_line_status_t ret;

  if (c.flags & USART_NO_RX) {
    return GPS_LINE_CKERR;
  }
  if (c.flags & USART_FRAME_ERROR) {
    return GPS_LINE_MORE;
  }
  if (pp->bufidx >= sizeof(pp->buf)-1) {
    /* no more space in buffer */
    if (c.data == '$') {
      /* uBlox may intermix binary and NMEA sentences, at
       * least this is what I understand from docs */
      pp->bufidx = 0;
      pp->buf[(pp->bufidx)++] = c.data;
      return GPS_LINE_MORE;
    }
    if (c.data == '\n') {
      /* line finished -> reset */
      pp->bufidx = 0;
      /* but return error indication anyway */
    }
    return GPS_LINE_OVERFLOW;
  }

  if (pp->bufidx == 0) {
    /* save timestamp */
    gps_timestamp_start_of_message (parser);
  }

  pp->buf[pp->bufidx++] = c.data;
  if (c.data != '\n') {
    /* not finished yet */
    return GPS_LINE_MORE;
  }

  
  /* put in terminating NUL byte */
  pp->buf[pp->bufidx] = '\0';
  /* reset start index */
  pp->bufidx = 0;

  /* check checksum */
  if (nmea_line_csum_check (pp)) {
    return GPS_LINE_CKERR;
  }

  /* now we have a complete line with correct checksum
   * and we can start parsing */
  ret = nmea_line_parse (p);

  return ret;
}