nuttx-apps/gpsutils/minmea/minmea.c
2016-02-20 10:24:02 -06:00

855 lines
20 KiB
C

/****************************************************************************
* apps/include/cle.h
*
* Copyright © 2014 Kosma Moczek <kosma@cloudyourcar.com>
*
* This program is free software. It comes without any warranty, to the extent
* permitted by applicable law. You can redistribute it and/or modify it under
* the terms of the Do What The Fuck You Want To Public License, Version 2, as
* published by Sam Hocevar. See the COPYING file for more details.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <apps/gpsutils/minmea.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define boolstr(s) ((s) ? "true" : "false")
/****************************************************************************
* Private Functions
****************************************************************************/
static int hex2int(char c)
{
if (c >= '0' && c <= '9')
{
return c - '0';
}
if (c >= 'A' && c <= 'F')
{
return c - 'A' + 10;
}
if (c >= 'a' && c <= 'f')
{
return c - 'a' + 10;
}
return -1;
}
static inline bool minmea_isfield(char c)
{
return isprint((unsigned char) c) && c != ',' && c != '*';
}
/****************************************************************************
* Public Functions
****************************************************************************/
uint8_t minmea_checksum(FAR const char *sentence)
{
uint8_t checksum = 0x00;
/* Support senteces with or without the starting dollar sign. */
if (*sentence == '$')
{
sentence++;
}
/* The optional checksum is an XOR of all bytes between "$" and "*". */
while (*sentence && *sentence != '*')
{
checksum ^= *sentence++;
}
return checksum;
}
bool minmea_check(FAR const char *sentence, bool strict)
{
uint8_t checksum = 0x00;
/* Sequence length is limited. */
if (strlen(sentence) > MINMEA_MAX_LENGTH + 3)
{
return false;
}
/* A valid sentence starts with "$". */
if (*sentence++ != '$')
{
return false;
}
/* The optional checksum is an XOR of all bytes between "$" and "*". */
while (*sentence && *sentence != '*' &&
isprint((unsigned char) *sentence))
{
checksum ^= *sentence++;
}
/* If checksum is present... */
if (*sentence == '*')
{
int upper;
int lower;
int expected;
/* Extract checksum. */
sentence++;
upper = hex2int(*sentence++);
if (upper == -1)
{
return false;
}
lower = hex2int(*sentence++);
if (lower == -1)
{
return false;
}
expected = upper << 4 | lower;
/* Check for checksum mismatch. */
if (checksum != expected)
{
return false;
}
}
else if (strict)
{
/* Discard non-checksummed frames in strict mode. */
return false;
}
/* The only stuff allowed at this point is a newline. */
if (*sentence && strcmp(sentence, "\n") &&
strcmp(sentence, "\r\n"))
{
return false;
}
return true;
}
bool minmea_scan(FAR const char *sentence, FAR const char *format, ...)
{
bool result = false;
bool optional = false;
va_list ap;
va_start(ap, format);
const char *field = sentence;
#define next_field() \
do \
{ \
/* Progress to the next field. */ \
while (minmea_isfield(*sentence)) \
{ \
sentence++; \
/* Make sure there is a field there. */ \
if (*sentence == ',') \
{ \
sentence++; \
field = sentence; \
} \
else \
{ \
field = NULL; \
} \
} \
} \
while (0)
while (*format)
{
char type = *format++;
if (type == ';')
{
/* All further fields are optional. */
optional = true;
continue;
}
if (!field && !optional)
{
/* Field requested but we ran out if input. Bail out. */
goto parse_error;
}
switch (type)
{
/* Single character field (char). */
case 'c':
{
char value = '\0';
if (field && minmea_isfield(*field))
{
value = *field;
}
*va_arg(ap, char *) = value;
}
break;
/* Single character direction field (int). */
case 'd':
{
int value = 0;
if (field && minmea_isfield(*field))
{
switch (*field)
{
case 'N':
case 'E':
value = 1;
break;
case 'S':
case 'W':
value = -1;
break;
default:
goto parse_error;
}
}
*va_arg(ap, int *) = value;
}
break;
/* Fractional value with scale (struct minmea_float). */
case 'f':
{
int sign = 0;
int_least32_t value = -1;
int_least32_t scale = 0;
if (field)
{
while (minmea_isfield(*field))
{
if (*field == '+' && !sign && value == -1)
{
sign = 1;
}
else if (*field == '-' && !sign && value == -1)
{
sign = -1;
}
else if (isdigit((unsigned char) *field))
{
int digit = *field - '0';
if (value == -1)
{
value = 0;
}
if (value > (INT_LEAST32_MAX-digit) / 10)
{
/* we ran out of bits, what do we do? */
if (scale)
{
/* truncate extra precision */
break;
}
else
{
/* integer overflow. bail out. */
goto parse_error;
}
}
value = (10 * value) + digit;
if (scale)
{
scale *= 10;
}
}
else if (*field == '.' && scale == 0)
{
scale = 1;
}
else if (*field == ' ')
{
/* Allow spaces at the start of the field. Not NMEA
* conformant, but some modules do this.
*/
if (sign != 0 || value != -1 || scale != 0)
{
goto parse_error;
}
}
else
{
goto parse_error;
}
field++;
}
}
if ((sign || scale) && value == -1)
{
goto parse_error;
}
if (value == -1)
{
/* No digits were scanned. */
value = 0;
scale = 0;
}
else if (scale == 0)
{
/* No decimal point. */
scale = 1;
}
if (sign)
{
value *= sign;
}
*va_arg(ap, struct minmea_float *) =
(struct minmea_float) {value, scale};
}
break;
/* Integer value, default 0 (int). */
case 'i':
{
int value = 0;
if (field)
{
FAR char *endptr;
value = strtol(field, &endptr, 10);
if (minmea_isfield(*endptr))
{
goto parse_error;
}
}
*va_arg(ap, int *) = value;
}
break;
/* String value (char *). */
case 's':
{
char *buf = va_arg(ap, char *);
if (field)
{
while (minmea_isfield(*field))
{
*buf++ = *field++;
}
}
*buf = '\0';
}
break;
/* NMEA talker+sentence identifier (char *). */
case 't':
{
char *buf;
int f;
/* This field is always mandatory. */
if (!field)
{
goto parse_error;
}
if (field[0] != '$')
{
goto parse_error;
}
for (f = 0; f < 5; f++)
{
if (!minmea_isfield(field[1+f]))
{
goto parse_error;
}
}
buf = va_arg(ap, char *);
memcpy(buf, field+1, 5);
buf[5] = '\0';
}
break;
/* Date (int, int, int), -1 if empty. */
case 'D':
{
struct minmea_date *date = va_arg(ap, struct minmea_date *);
int d = -1;
int m = -1;
int y = -1;
int f;
if (field && minmea_isfield(*field))
{
/* Always six digits. */
for (f = 0; f < 6; f++)
{
if (!isdigit((unsigned char) field[f]))
{
goto parse_error;
}
}
d = strtol((char[]) {field[0], field[1], '\0'}, NULL, 10);
m = strtol((char[]) {field[2], field[3], '\0'}, NULL, 10);
y = strtol((char[]) {field[4], field[5], '\0'}, NULL, 10);
}
date->day = d;
date->month = m;
date->year = y;
}
break;
/* Time (int, int, int, int), -1 if empty. */
case 'T':
{
struct minmea_time *time_ = va_arg(ap, struct minmea_time *);
int h = -1;
int i = -1;
int s = -1;
int u = -1;
int f;
if (field && minmea_isfield(*field))
{
/* Minimum required: integer time. */
for (f = 0; f < 6; f++)
{
if (!isdigit((unsigned char) field[f]))
{
goto parse_error;
}
}
h = strtol((char[]) {field[0], field[1], '\0'}, NULL, 10);
i = strtol((char[]) {field[2], field[3], '\0'}, NULL, 10);
s = strtol((char[]) {field[4], field[5], '\0'}, NULL, 10);
field += 6;
/* Extra: fractional time. Saved as microseconds. */
if (*field++ == '.')
{
int value = 0;
int scale = 1000000;
while (isdigit((unsigned char) *field) && scale > 1)
{
value = (value * 10) + (*field++ - '0');
scale /= 10;
}
u = value * scale;
}
else
{
u = 0;
}
}
time_->hours = h;
time_->minutes = i;
time_->seconds = s;
time_->microseconds = u;
}
break;
/* Ignore the field. */
case '_':
{
}
break;
default:
{
goto parse_error;
}
break;
}
next_field();
}
result = true;
parse_error:
va_end(ap);
return result;
}
bool minmea_talker_id(char talker[3], FAR const char *sentence)
{
char type[6];
if (!minmea_scan(sentence, "t", type))
{
return false;
}
talker[0] = type[0];
talker[1] = type[1];
talker[2] = '\0';
return true;
}
enum minmea_sentence_id minmea_sentence_id(FAR const char *sentence,
bool strict)
{
if (!minmea_check(sentence, strict))
return MINMEA_INVALID;
char type[6];
if (!minmea_scan(sentence, "t", type))
{
return MINMEA_INVALID;
}
if (!strcmp(type+2, "RMC"))
{
return MINMEA_SENTENCE_RMC;
}
if (!strcmp(type+2, "GGA"))
{
return MINMEA_SENTENCE_GGA;
}
if (!strcmp(type+2, "GSA"))
{
return MINMEA_SENTENCE_GSA;
}
if (!strcmp(type+2, "GLL"))
{
return MINMEA_SENTENCE_GLL;
}
if (!strcmp(type+2, "GST"))
{
return MINMEA_SENTENCE_GST;
}
if (!strcmp(type+2, "GSV"))
{
return MINMEA_SENTENCE_GSV;
}
return MINMEA_UNKNOWN;
}
bool minmea_parse_rmc(FAR struct minmea_sentence_rmc *frame,
FAR const char *sentence)
{
/* $GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62 */
char type[6];
char validity;
int latitude_direction;
int longitude_direction;
int variation_direction;
if (!minmea_scan(sentence, "tTcfdfdffDfd",
type,
&frame->time,
&validity,
&frame->latitude, &latitude_direction,
&frame->longitude, &longitude_direction,
&frame->speed,
&frame->course,
&frame->date,
&frame->variation, &variation_direction))
{
return false;
}
if (strcmp(type+2, "RMC"))
{
return false;
}
frame->valid = (validity == 'A');
frame->latitude.value *= latitude_direction;
frame->longitude.value *= longitude_direction;
frame->variation.value *= variation_direction;
return true;
}
bool minmea_parse_gga(FAR struct minmea_sentence_gga *frame,
FAR const char *sentence)
{
/* $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47 */
char type[6];
int latitude_direction;
int longitude_direction;
if (!minmea_scan(sentence, "tTfdfdiiffcfci_",
type,
&frame->time,
&frame->latitude, &latitude_direction,
&frame->longitude, &longitude_direction,
&frame->fix_quality,
&frame->satellites_tracked,
&frame->hdop,
&frame->altitude, &frame->altitude_units,
&frame->height, &frame->height_units,
&frame->dgps_age))
{
return false;
}
if (strcmp(type+2, "GGA"))
{
return false;
}
frame->latitude.value *= latitude_direction;
frame->longitude.value *= longitude_direction;
return true;
}
bool minmea_parse_gsa(FAR struct minmea_sentence_gsa *frame,
FAR const char *sentence)
{
/* $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39 */
char type[6];
if (!minmea_scan(sentence, "tciiiiiiiiiiiiifff",
type,
&frame->mode,
&frame->fix_type,
&frame->sats[0],
&frame->sats[1],
&frame->sats[2],
&frame->sats[3],
&frame->sats[4],
&frame->sats[5],
&frame->sats[6],
&frame->sats[7],
&frame->sats[8],
&frame->sats[9],
&frame->sats[10],
&frame->sats[11],
&frame->pdop,
&frame->hdop,
&frame->vdop))
{
return false;
}
if (strcmp(type+2, "GSA"))
{
return false;
}
return true;
}
bool minmea_parse_gll(FAR struct minmea_sentence_gll *frame,
FAR const char *sentence)
{
/* $GPGLL,3723.2475,N,12158.3416,W,161229.487,A,A*41$; */
char type[6];
int latitude_direction;
int longitude_direction;
if (!minmea_scan(sentence, "tfdfdTc;c",
type,
&frame->latitude, &latitude_direction,
&frame->longitude, &longitude_direction,
&frame->time,
&frame->status,
&frame->mode))
{
return false;
}
if (strcmp(type+2, "GLL"))
{
return false;
}
frame->latitude.value *= latitude_direction;
frame->longitude.value *= longitude_direction;
return true;
}
bool minmea_parse_gst(FAR struct minmea_sentence_gst *frame,
FAR const char *sentence)
{
/* $GPGST,024603.00,3.2,6.6,4.7,47.3,5.8,5.6,22.0*58 */
char type[6];
if (!minmea_scan(sentence, "tTfffffff",
type,
&frame->time,
&frame->rms_deviation,
&frame->semi_major_deviation,
&frame->semi_minor_deviation,
&frame->semi_major_orientation,
&frame->latitude_error_deviation,
&frame->longitude_error_deviation,
&frame->altitude_error_deviation))
{
return false;
}
if (strcmp(type+2, "GST"))
{
return false;
}
return true;
}
bool minmea_parse_gsv(FAR struct minmea_sentence_gsv *frame,
FAR const char *sentence)
{
/* $GPGSV,3,1,11,03,03,111,00,04,15,270,00,06,01,010,00,13,06,292,00*74
* $GPGSV,3,3,11,22,42,067,42,24,14,311,43,27,05,244,00,,,,*4D
* $GPGSV,4,2,11,08,51,203,30,09,45,215,28*75
* $GPGSV,4,4,13,39,31,170,27*40
* $GPGSV,4,4,13*7B */
char type[6];
if (!minmea_scan(sentence, "tiii;iiiiiiiiiiiiiiii",
type,
&frame->total_msgs,
&frame->msg_nr,
&frame->total_sats,
&frame->sats[0].nr,
&frame->sats[0].elevation,
&frame->sats[0].azimuth,
&frame->sats[0].snr,
&frame->sats[1].nr,
&frame->sats[1].elevation,
&frame->sats[1].azimuth,
&frame->sats[1].snr,
&frame->sats[2].nr,
&frame->sats[2].elevation,
&frame->sats[2].azimuth,
&frame->sats[2].snr,
&frame->sats[3].nr,
&frame->sats[3].elevation,
&frame->sats[3].azimuth,
&frame->sats[3].snr))
{
return false;
}
if (strcmp(type+2, "GSV"))
{
return false;
}
return true;
}
int minmea_gettime(FAR struct timespec *ts,
FAR const struct minmea_date *date,
FAR const struct minmea_time *time_)
{
struct tm tm;
if (date->year == -1 || time_->hours == -1)
{
return -1;
}
memset(&tm, 0, sizeof(tm));
tm.tm_year = 2000 + date->year - 1900;
tm.tm_mon = date->month - 1;
tm.tm_mday = date->day;
tm.tm_hour = time_->hours;
tm.tm_min = time_->minutes;
tm.tm_sec = time_->seconds;
/* See README.md if your system lacks timegm(). */
time_t timestamp = mktime(&tm);
if (timestamp != -1)
{
ts->tv_sec = timestamp;
ts->tv_nsec = time_->microseconds * 1000;
return 0;
}
else
{
return -1;
}
}