// Processes a just-completed term
// Returns true if new sentence has just passed checksum test and is validated
bool AP_GPS_NMEA::_term_complete()
{
// handle the last term in a message
if (_is_checksum_term) {
uint8_t checksum = 16 * _from_hex(_term[0]) + _from_hex(_term[1]);
if (checksum == _parity) {
if (_gps_data_good) {
switch (_sentence_type) {
case _GPS_SENTENCE_GPRMC:
time = _new_time;
date = _new_date;
latitude = _new_latitude * 10; // degrees*10e5 -> 10e7
longitude = _new_longitude * 10; // degrees*10e5 -> 10e7
ground_speed = _new_speed;
ground_course = _new_course;
fix = true;
break;
case _GPS_SENTENCE_GPGGA:
altitude = _new_altitude;
time = _new_time;
latitude = _new_latitude * 10; // degrees*10e5 -> 10e7
longitude = _new_longitude * 10; // degrees*10e5 -> 10e7
num_sats = _new_satellite_count;
hdop = _new_hdop;
fix = true;
break;
case _GPS_SENTENCE_GPVTG:
ground_speed = _new_speed;
ground_course = _new_course;
// VTG has no fix indicator, can't change fix status
break;
}
} else {
switch (_sentence_type) {
case _GPS_SENTENCE_GPRMC:
case _GPS_SENTENCE_GPGGA:
// Only these sentences give us information about
// fix status.
fix = false;
}
}
// we got a good message
return true;
}
// we got a bad message, ignore it
return false;
}
// the first term determines the sentence type
if (_term_number == 0) {
if (!strcmp_P(_term, _gprmc_string)) {
_sentence_type = _GPS_SENTENCE_GPRMC;
} else if (!strcmp_P(_term, _gpgga_string)) {
_sentence_type = _GPS_SENTENCE_GPGGA;
} else if (!strcmp_P(_term, _gpvtg_string)) {
_sentence_type = _GPS_SENTENCE_GPVTG;
// VTG may not contain a data qualifier, presume the solution is good
// unless it tells us otherwise.
_gps_data_good = true;
} else {
_sentence_type = _GPS_SENTENCE_OTHER;
}
return false;
}
// 32 = RMC, 64 = GGA, 96 = VTG
if (_sentence_type != _GPS_SENTENCE_OTHER && _term[0]) {
switch (_sentence_type + _term_number) {
// operational status
//
case _GPS_SENTENCE_GPRMC + 2: // validity (RMC)
_gps_data_good = _term[0] == 'A';
break;
case _GPS_SENTENCE_GPGGA + 6: // Fix data (GGA)
_gps_data_good = _term[0] > '0';
break;
case _GPS_SENTENCE_GPVTG + 9: // validity (VTG) (we may not see this field)
_gps_data_good = _term[0] != 'N';
break;
case _GPS_SENTENCE_GPGGA + 7: // satellite count (GGA)
_new_satellite_count = atol(_term);
break;
case _GPS_SENTENCE_GPGGA + 8: // HDOP (GGA)
_new_hdop = _parse_decimal();
break;
// time and date
//
case _GPS_SENTENCE_GPRMC + 1: // Time (RMC)
case _GPS_SENTENCE_GPGGA + 1: // Time (GGA)
_new_time = _parse_decimal();
break;
case _GPS_SENTENCE_GPRMC + 9: // Date (GPRMC)
_new_date = atol(_term);
break;
// location
//
case _GPS_SENTENCE_GPRMC + 3: // Latitude
case _GPS_SENTENCE_GPGGA + 2:
_new_latitude = _parse_degrees();
break;
case _GPS_SENTENCE_GPRMC + 4: // N/S
case _GPS_SENTENCE_GPGGA + 3:
if (_term[0] == 'S')
_new_latitude = -_new_latitude;
break;
case _GPS_SENTENCE_GPRMC + 5: // Longitude
case _GPS_SENTENCE_GPGGA + 4:
_new_longitude = _parse_degrees();
break;
case _GPS_SENTENCE_GPRMC + 6: // E/W
case _GPS_SENTENCE_GPGGA + 5:
if (_term[0] == 'W')
_new_longitude = -_new_longitude;
break;
case _GPS_SENTENCE_GPGGA + 9: // Altitude (GPGGA)
_new_altitude = _parse_decimal();
break;
// course and speed
//
case _GPS_SENTENCE_GPRMC + 7: // Speed (GPRMC)
case _GPS_SENTENCE_GPVTG + 5: // Speed (VTG)
_new_speed = (_parse_decimal() * 514) / 1000; // knots-> m/sec, approximiates * 0.514
break;
case _GPS_SENTENCE_GPRMC + 8: // Course (GPRMC)
case _GPS_SENTENCE_GPVTG + 1: // Course (VTG)
_new_course = _parse_decimal();
break;
}
}
return false;
}
int parse_json_file(FILE *fptr, JSON_T *json_obj)
{
int ret;
char *key;
char first_meet;
char *tmpstr;
long long tmpnum;
double floatnum, decimal;
JSON_T *value;
if (!json_obj)
return -ENOMEM;
key = NULL;
tmpstr = NULL;
value = NULL;
memset(json_obj, 0, sizeof(JSON_T));
json_obj->type = JSON;
json_obj->keys = NULL;
_PARSE_SYMBOL(fptr, "{", NULL);
while (!feof(fptr)) {
_PARSE_SYMBOL(fptr, "\"}", &first_meet);
if (first_meet == '}')
break;
ret = _parse_string(fptr, &key);
if (ret < 0)
goto error_handle;
//printf("string = %s : ", key);
_PARSE_SYMBOL(fptr, ":", NULL);
_PARSE_SYMBOL(fptr, "\"{-0123456789.", &first_meet);
value = malloc(sizeof(JSON_T));
if (!value) {
ret = -ENOMEM;
goto error_handle;
}
memset(value, 0, sizeof(JSON_T));
switch (first_meet) {
case '\"':
ret = _parse_string(fptr, &tmpstr);
if (ret < 0)
goto error_handle;
value->type = STRING;
value->str = tmpstr;
//printf("value = %s\n", tmpstr);
break;
case '{':
fseek(fptr, -1, SEEK_CUR);
ret = parse_json_file(fptr, value);
if (ret < 0)
goto error_handle;
break;
case '-':
ret = _parse_integer(fptr, &tmpnum);
if (ret < 0) {
goto error_handle;
} else if (ret == 1) {
ret = _parse_decimal(fptr, &decimal);
if (ret < 0)
goto error_handle;
floatnum = tmpnum + decimal;
value->type = FLOAT;
value->floating = -floatnum;
} else {
value->type = INTEGER;
value->integer = -tmpnum;
}
//printf("value = %lld\n", -tmpnum);
break;
default:
fseek(fptr, -1, SEEK_CUR);
ret = _parse_integer(fptr, &tmpnum);
if (ret < 0) {
goto error_handle;
} else if (ret == 1) {
ret = _parse_decimal(fptr, &decimal);
if (ret < 0)
goto error_handle;
floatnum = tmpnum + decimal;
value->type = FLOAT;
value->floating = floatnum;
} else {
value->type = INTEGER;
value->integer = tmpnum;
}
//printf("value = %lld\n", tmpnum);
break;
}
/* Insert */
ret = insert_json_obj(json_obj, key, value);
if (ret < 0)
goto error_handle;
key = NULL;
tmpstr = NULL;
value = NULL;
_PARSE_SYMBOL(fptr, "},", &first_meet);
if (first_meet == '}')
break;
}
return 0;
error_handle:
/* Do not free self because it perhaps results in
double free error when recursing */
free_json_obj_field(json_obj);
if (key)
free(key);
if (tmpstr)
free(tmpstr);
if (value)
free(value);
return ret;
}