#include <string.h>
#include "nmea.h"
unsigned char hex2bin( char c )
{
if( ( c >= 'A') && ( c <= 'F') ) {
return c - 'A';
}
else if( ( c >= 'a') && ( c <= 'f') ) {
return c - 'a';
}
else {
return c - '0';
}
}
char nmea_check_crc( char *buf )
{
unsigned char crc = 0;
while( *buf != '*' ) {
crc ^= *buf++;
}
return ( ( crc & 0x0F ) == hex2bin( *buf ) ) &&
( ( crc >> 4 ) == hex2bin( *(buf+1) ) );
}
#define ARRAY_SIZE( array ) (sizeof(array)/sizeof(array[0]))
//釉艺嗽找�, 闲捎僮晾萘� nmea 酉下菖紊�
typedef struct _nmea_message {
char * id; //赡盼陨粕肆韵� 酉下菖紊�
char (*parser)( char *buf, void *data ); //辛矣乓 酉下菖紊�
void *data; //遗谡特粤� 辛矣晌橇 酉下菖紊�
} nmea_message_t;
char *nmea_next_field( char* buf)
{
// return strtok( buf, ',' );
while( *buf++ != ',' );
return buf;
}
typedef struct gms_rmc {
unsigned short valid;
} nmea_rmc_t;
nmea_rmc_t nmea_rmc_data;
//$GPRMC,171729.000,A,6001.5972,N,03012.7352,E,0.03,0.00,111212,,,A*6B
char nmea_rmc_parser( char *buf, void *data )
{
char *ptr_end;
nmea_rmc_t* rmc = (nmea_rmc_t*)data;
memset( rmc, 0, sizeof( nmea_rmc_t ) );
/*
printf( "buf =%s" , buf );
rmc->utc_time = strtod( buf, &ptr_end );
printf( "time %lu \r\n", (unsigned long)rmc->utc_time );
buf = nmea_next_field( buf );
if( *buf == 'A') {
}
buf = nmea_next_field( buf );
printf( "buf =%s" , buf );
rmc->latitude = atof( buf );
buf = nmea_next_field( buf );
if( *buf == 'S') {
rmc->latitude = -rmc->latitude;
}
printf( "latitude %lu \r\n", (unsigned long)rmc->latitude );
buf = nmea_next_field( buf );
printf( "buf =%s" , buf );
rmc->longitude = atof( buf );
buf = nmea_next_field( buf );
if( *buf == 'W') {
rmc->longitude = -rmc->longitude;
}
printf( "longitude %lu \r\n", (unsigned long)rmc->longitude );
buf = nmea_next_field( buf );
printf( "buf =%s" , buf );
rmc->fix_status = atoi( buf );
printf( "fix_status %u \r\n", rmc->fix_status );
buf = nmea_next_field( buf );
printf( "buf =%s" , buf );
rmc->satelits = atoi( buf );
printf( "satelits %u \r\n", rmc->satelits );
*/
return 0;
}
nmea_message_t nmea_messages[] =
{
/*
{
.cmd = "GPGGA",
.parser = nmea_gga_parser,
.data = &nmea_gga_data,
},
*/
{
.id = "GPRMS",
.parser = nmea_rmc_parser,
.data = &nmea_rmc_data,
},
};
unsigned char nmea_parser( char* buf )
{
unsigned char i;
if( *buf++ != '$' ) {
return -1;
}
if( !nmea_check_crc( buf ) ) {
return -1; //CRC fail
}
for( i = 0; i< ARRAY_SIZE( nmea_messages ); i++ ) {
if( strncmp( buf, nmea_messages[i].id, strlen( nmea_messages[i].id ) ) == 0 ) {
if( nmea_messages[i].parser ) {
buf = nmea_next_field( buf );
return nmea_messages[i].parser( buf, nmea_messages[i].data );
}
return -1;
}
}
return -1;
}
