nmeap.h File Reference

#include "nmeap_def.h"

Go to the source code of this file.

Data Structures
struct	nmeap_gga
struct	nmeap_rmc
Defines
#define	NMEAP_MAX_SENTENCES   8
#define	NMEAP_MAX_SENTENCE_NAME_LENGTH   5
#define	NMEAP_MAX_SENTENCE_LENGTH   255
#define	NMEAP_MAX_TOKENS   24
#define	NMEAP_GPGGA   1
#define	NMEAP_GPRMC   2
#define	NMEAP_USER   100
Typedefs
typedef void(*	nmeap_callout_t )(struct nmeap_context *context, void *sentence_data, void *user_data)
typedef int(*	nmeap_sentence_parser_t )(struct nmeap_context *context, struct nmeap_sentence *sentence)
typedef nmeap_gga	nmeap_gga_t
typedef nmeap_rmc	nmeap_rmc_t
Functions
int	nmeap_init (nmeap_context_t *context, void *user_data)
int	nmeap_addParser (nmeap_context_t *context, const char *sentence_name, nmeap_sentence_parser_t sentence_parser, nmeap_callout_t sentence_callout, void *sentence_data)
int	nmeap_parseBuffer (nmeap_context_t *context, const char *buffer, int *length)
int	nmeap_parse (nmeap_context_t *context, char ch)
int	nmeap_gpgga (nmeap_context_t *context, nmeap_sentence_t *sentence)
int	nmeap_gprmc (nmeap_context_t *context, nmeap_sentence_t *sentence)
double	nmeap_latitude (const char *plat, const char *phem)
double	nmeap_longitude (const char *plat, const char *phem)

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Define Documentation

#define NMEAP_GPGGA   1

#define NMEAP_GPRMC   2

#define NMEAP_MAX_SENTENCE_LENGTH   255

max length of a complete sentence. the standard says 82 bytes, but its probably better to go at least 128 since some units don't adhere to the 82 bytes especially for proprietary sentences

#define NMEAP_MAX_SENTENCE_NAME_LENGTH   5

length of sentence name. leave this at 5 unless you really know what you are doing

#define NMEAP_MAX_SENTENCES   8

maximum number of sentence parsers supported

#define NMEAP_MAX_TOKENS   24

max tokens in one sentence. 24 is enough for any standard sentence

#define NMEAP_USER   100

user defined parsers should make ID numbers using NMEAP_USER as the base value, plus some increment

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Typedef Documentation

typedef void(* nmeap_callout_t)(struct nmeap_context *context,void *sentence_data,void *user_data)

sentence callout function type a callout is fired for each registered sentence type the callout gets the object context and a pointer to sentence specific data. the callout must cast the 'sentence_data' to the appropriate type for that callout Parameters: context  nmea object context sentence_data  sentence specific data

typedef struct nmeap_gga nmeap_gga_t

typedef struct nmeap_rmc nmeap_rmc_t

typedef int(* nmeap_sentence_parser_t)(struct nmeap_context *context,struct nmeap_sentence *sentence)

sentence parser function type stored in the object context and called internally when the sentence name matches the specified value the callout gets the object context and a pointer to sentence specific data. the callout must cast the 'sentence_data' to the appropriate type for that callout Parameters: context  nmea object context sentence_data  sentence specific data Returns: id of sentence (each sentence parser knows its own ID)

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Function Documentation

int nmeap_addParser (  nmeap_context_t *  context, const char *  sentence_name, nmeap_sentence_parser_t  sentence_parser, nmeap_callout_t  sentence_callout, void *  sentence_data )

register an NMEA sentence parser Parameters: context  nmea object context sentence_name  string matching the sentence name for this parser. e.g. "GPGGA". not including the '$' sentence_parser  parser function for this sentence sentence_callout  callout triggered when this sentence is received and parsed. if null, no callout is triggered for this sentence sentence_data  user allocated sentence specific data defined by the application. the parser uses this data item to store the extracted data. This data object needs to persist over the life of the parser, so be careful if allocated on the stack. Returns: 0 if registered ok, -1 if registration failed

int nmeap_gpgga (  nmeap_context_t *  context, nmeap_sentence_t *  sentence )

built-in parser for GGA sentences. Parameters: context  nmea object context sentence  sentence object for this parser

int nmeap_gprmc (  nmeap_context_t *  context, nmeap_sentence_t *  sentence )

built-in parser for RMC sentences. Parameters: context  nmea object context sentence  sentence object for this parser

int nmeap_init (  nmeap_context_t *  context, void *  user_data )

initialize an NMEA parser. call this function to initialize a user allocated context object Parameters: context  nmea object context. allocated by user statically or dynamically. user_data  pointer to user defined data Returns: 0 if ok, -1 if initialization failed

double nmeap_latitude (  const char *  plat, const char *  phem )

extract latitude from 2 tokens in ddmm.mmmm,h format. Parameters: plat  pointer to token with numerical latitude phem  pointer to token with hemisphere Returns: latitude in degrees and fractional degrees

double nmeap_longitude (  const char *  plat, const char *  phem )

extract longitude from 2 tokens in ddmm.mmmm,h format. Parameters: plat  pointer to token with numerical longitude phem  pointer to token with hemisphere Returns: longitude in degrees and fractional degrees

int nmeap_parse (  nmeap_context_t *  context, char  ch )

parse one character of nmea data. Parameters: context  nmea object context ch  input character Returns: -1 if error, 0 if the data did not complete a sentence, sentence code if a sentence was found in the stream

int nmeap_parseBuffer (  nmeap_context_t *  context, const char *  buffer, int *  length )

parse a buffer of nmea data. Parameters: context  nmea object context buffer  buffer of input characters length  [in,out] pointer to length of buffer. on return, contains number of characters not used for the current sentence Returns: -1 if error, 0 if the data did not complete a sentence, sentence code if a sentence was found in the stream

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