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/*
* 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.
*/
#ifndef MINMEA_H
#define MINMEA_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <errno.h>
#include <time.h>
#include <math.h>
#define MINMEA_MAX_LENGTH 80
enum minmea_sentence_id {
MINMEA_INVALID = -1,
MINMEA_UNKNOWN = 0,
MINMEA_SENTENCE_RMC,
MINMEA_SENTENCE_GGA,
MINMEA_SENTENCE_GSA,
MINMEA_SENTENCE_GLL,
MINMEA_SENTENCE_GST,
MINMEA_SENTENCE_GSV,
};
struct minmea_float {
int_least32_t value;
int_least32_t scale;
};
struct minmea_date {
int day;
int month;
int year;
};
struct minmea_time {
int hours;
int minutes;
int seconds;
int microseconds;
};
struct minmea_sentence_rmc {
struct minmea_time time;
bool valid;
struct minmea_float latitude;
struct minmea_float longitude;
struct minmea_float speed;
struct minmea_float course;
struct minmea_date date;
struct minmea_float variation;
};
struct minmea_sentence_gga {
struct minmea_time time;
struct minmea_float latitude;
struct minmea_float longitude;
int fix_quality;
int satellites_tracked;
struct minmea_float hdop;
struct minmea_float altitude; char altitude_units;
struct minmea_float height; char height_units;
int dgps_age;
};
enum minmea_gll_status {
MINMEA_GLL_STATUS_DATA_VALID = 'A',
MINMEA_GLL_STATUS_DATA_NOT_VALID = 'V',
};
enum minmea_gll_mode {
MINMEA_GLL_MODE_AUTONOMOUS = 'A',
MINMEA_GLL_MODE_DPGS = 'D',
MINMEA_GLL_MODE_DR = 'E',
};
struct minmea_sentence_gll {
struct minmea_float latitude;
struct minmea_float longitude;
struct minmea_time time;
char status;
char mode;
};
struct minmea_sentence_gst {
struct minmea_time time;
struct minmea_float rms_deviation;
struct minmea_float semi_major_deviation;
struct minmea_float semi_minor_deviation;
struct minmea_float semi_major_orientation;
struct minmea_float latitude_error_deviation;
struct minmea_float longitude_error_deviation;
struct minmea_float altitude_error_deviation;
};
enum minmea_gsa_mode {
MINMEA_GPGSA_MODE_AUTO = 'A',
MINMEA_GPGSA_MODE_FORCED = 'M',
};
enum minmea_gsa_fix_type {
MINMEA_GPGSA_FIX_NONE = 1,
MINMEA_GPGSA_FIX_2D = 2,
MINMEA_GPGSA_FIX_3D = 3,
};
struct minmea_sentence_gsa {
char mode;
int fix_type;
int sats[12];
struct minmea_float pdop;
struct minmea_float hdop;
struct minmea_float vdop;
};
struct minmea_sat_info {
int nr;
int elevation;
int azimuth;
int snr;
};
struct minmea_sentence_gsv {
int total_msgs;
int msg_nr;
int total_sats;
struct minmea_sat_info sats[4];
};
/**
* Calculate raw sentence checksum. Does not check sentence integrity.
*/
uint8_t minmea_checksum(const char *sentence);
/**
* Check sentence validity and checksum. Returns true for valid sentences.
*/
bool minmea_check(const char *sentence, bool strict);
/**
* Determine talker identifier.
*/
bool minmea_talker_id(char talker[3], const char *sentence);
/**
* Determine sentence identifier.
*/
enum minmea_sentence_id minmea_sentence_id(const char *sentence, bool strict);
/**
* Scanf-like processor for NMEA sentences. Supports the following formats:
* c - single character (char *)
* d - direction, returned as 1/-1, default 0 (int *)
* f - fractional, returned as value + scale (int *, int *)
* i - decimal, default zero (int *)
* s - string (char *)
* t - talker identifier and type (char *)
* T - date/time stamp (int *, int *, int *)
* Returns true on success. See library source code for details.
*/
bool minmea_scan(const char *sentence, const char *format, ...);
/*
* Parse a specific type of sentence. Return true on success.
*/
bool minmea_parse_rmc(struct minmea_sentence_rmc *frame, const char *sentence);
bool minmea_parse_gga(struct minmea_sentence_gga *frame, const char *sentence);
bool minmea_parse_gsa(struct minmea_sentence_gsa *frame, const char *sentence);
bool minmea_parse_gll(struct minmea_sentence_gll *frame, const char *sentence);
bool minmea_parse_gst(struct minmea_sentence_gst *frame, const char *sentence);
bool minmea_parse_gsv(struct minmea_sentence_gsv *frame, const char *sentence);
/**
* Convert GPS UTC date/time representation to a UNIX timestamp.
*/
int minmea_gettime(struct timespec *ts, const struct minmea_date *date, const struct minmea_time *time_);
/**
* Rescale a fixed-point value to a different scale. Rounds towards zero.
*/
static inline int_least32_t minmea_rescale(struct minmea_float *f, int_least32_t new_scale)
{
if (f->scale == 0)
return 0;
if (f->scale == new_scale)
return f->value;
if (f->scale > new_scale)
return (f->value + ((f->value > 0) - (f->value < 0)) * f->scale/new_scale/2) / (f->scale/new_scale);
else
return f->value * (new_scale/f->scale);
}
/**
* Convert a fixed-point value to a floating-point value.
* Returns NaN for "unknown" values.
*/
static inline float minmea_tofloat(struct minmea_float *f)
{
if (f->scale == 0)
return NAN;
return (float) f->value / (float) f->scale;
}
/**
* Convert a raw coordinate to a floating point DD.DDD... value.
* Returns NaN for "unknown" values.
*/
static inline float minmea_tocoord(struct minmea_float *f)
{
if (f->scale == 0)
return NAN;
int_least32_t degrees = f->value / (f->scale * 100);
int_least32_t minutes = f->value % (f->scale * 100);
return (float) degrees + (float) minutes / (60 * f->scale);
}
#ifdef __cplusplus
}
#endif
#endif /* MINMEA_H */
/* vim: set ts=4 sw=4 et: */
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