File syn_nmea.c¶

FileList > proto > syn_nmea.c

NMEA 0183 / GNSS sentence parser and encoder implementation.

#include "../util/syn_assert.h"
#include "syn_nmea.h"
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Public Functions¶

Type	Name
uint8_t	syn_nmea_checksum (const char * sentence) Calculate XOR checksum of an NMEA sentence payload (between '$' and '').*
SYN_NMEA_SentenceType	syn_nmea_get_type (const char * sentence) Identify sentence type from NMEA string.
double	syn_nmea_parse_coord (const char * nmea_coord, char dir) Parse NMEA DDMM.MMMM coordinate string and direction indicator.
bool	syn_nmea_parse_gga (const char * sentence, SYN_NMEA_GGA * gga) Parse a $GPGGA / $GNGGA sentence.
bool	syn_nmea_parse_gsa (const char * sentence, SYN_NMEA_GSA * gsa) Parse a $GPGSA / $GNGSA sentence.
bool	syn_nmea_parse_rmc (const char * sentence, SYN_NMEA_RMC * rmc) Parse a $GPRMC / $GNRMC sentence.
bool	syn_nmea_parse_vtg (const char * sentence, SYN_NMEA_VTG * vtg) Parse a $GPVTG / $GNVTG sentence.
bool	syn_nmea_parse_zda (const char * sentence, SYN_NMEA_ZDA * zda) Parse a $GPZDA / $GNZDA sentence.
bool	syn_nmea_parser_feed (SYN_NMEA_Parser * parser, char byte, char * out_sentence) Feed a byte into the NMEA streaming parser.
void	syn_nmea_parser_init (SYN_NMEA_Parser * parser) Initialize an NMEA streaming parser.
bool	syn_nmea_validate (const char * sentence) Validate an NMEA sentence string (checks start '$', 'XX' checksum, and CRLF).*

Public Static Functions¶

Type	Name
bool	get_field (const char * sentence, uint8_t index, char * dest, size_t max_len)
uint8_t	hex2dec (char c)
void	parse_time (const char * field, uint8_t * h, uint8_t * m, uint8_t * s, uint16_t * ms)

Public Functions Documentation¶

function syn_nmea_checksum¶

Calculate XOR checksum of an NMEA sentence payload (between '$' and '*').

uint8_t syn_nmea_checksum (
    const char * sentence
)

Parameters:

sentence NMEA sentence string.

Returns:

8-bit XOR checksum value.

function syn_nmea_get_type¶

Identify sentence type from NMEA string.

SYN_NMEA_SentenceType syn_nmea_get_type (
    const char * sentence
)

Parameters:

sentence NMEA sentence string.

Returns:

SYN_NMEA_SentenceType enum.

function syn_nmea_parse_coord¶

Parse NMEA DDMM.MMMM coordinate string and direction indicator.

double syn_nmea_parse_coord (
    const char * nmea_coord,
    char dir
)

Parameters:

nmea_coord Coordinate string (e.g. "4807.038").
dir Direction char ('N', 'S', 'E', 'W').

Returns:

Decimal degrees (+N/+E, -S/-W).

function syn_nmea_parse_gga¶

Parse a $GPGGA / $GNGGA sentence.

bool syn_nmea_parse_gga (
    const char * sentence,
    SYN_NMEA_GGA * gga
)

Parameters:

sentence NMEA sentence string.
gga Pointer to destination GGA struct.

Returns:

true on success.

function syn_nmea_parse_gsa¶

Parse a $GPGSA / $GNGSA sentence.

bool syn_nmea_parse_gsa (
    const char * sentence,
    SYN_NMEA_GSA * gsa
)

Parameters:

sentence NMEA sentence string.
gsa Pointer to destination GSA struct.

Returns:

true on success.

function syn_nmea_parse_rmc¶

Parse a $GPRMC / $GNRMC sentence.

bool syn_nmea_parse_rmc (
    const char * sentence,
    SYN_NMEA_RMC * rmc
)

Parameters:

sentence NMEA sentence string.
rmc Pointer to destination RMC struct.

Returns:

true on success.

function syn_nmea_parse_vtg¶

Parse a $GPVTG / $GNVTG sentence.

bool syn_nmea_parse_vtg (
    const char * sentence,
    SYN_NMEA_VTG * vtg
)

Parameters:

sentence NMEA sentence string.
vtg Pointer to destination VTG struct.

Returns:

true on success.

function syn_nmea_parse_zda¶

Parse a $GPZDA / $GNZDA sentence.

bool syn_nmea_parse_zda (
    const char * sentence,
    SYN_NMEA_ZDA * zda
)

Parameters:

sentence NMEA sentence string.
zda Pointer to destination ZDA struct.

Returns:

true on success.

function syn_nmea_parser_feed¶

Feed a byte into the NMEA streaming parser.

bool syn_nmea_parser_feed (
    SYN_NMEA_Parser * parser,
    char byte,
    char * out_sentence
)

Parameters:

parser Pointer to parser instance.
byte Received character.
out_sentence Output buffer for completed NMEA sentence string (if returns true).

Returns:

true if a complete, valid NMEA sentence was received.

function syn_nmea_parser_init¶

Initialize an NMEA streaming parser.

void syn_nmea_parser_init (
    SYN_NMEA_Parser * parser
)

Parameters:

parser Pointer to parser state machine.

function syn_nmea_validate¶

Validate an NMEA sentence string (checks start '$', '*XX' checksum, and CRLF).

bool syn_nmea_validate (
    const char * sentence
)

Parameters:

sentence NMEA sentence string.

Returns:

true if valid sentence and matching checksum.

Public Static Functions Documentation¶

function get_field¶

static bool get_field (
    const char * sentence,
    uint8_t index,
    char * dest,
    size_t max_len
)

function hex2dec¶

static uint8_t hex2dec (
    char c
)

function parse_time¶

static void parse_time (
    const char * field,
    uint8_t * h,
    uint8_t * m,
    uint8_t * s,
    uint16_t * ms
)

The documentation for this class was generated from the following file src/syntropic/proto/syn_nmea.c