flightgear/utils/GPSsmooth/UGear_command.cxx
2022-10-20 20:29:11 +08:00

107 lines
2.3 KiB
C++

#include <cstring>
#include <cstdio>
#include "UGear_command.hxx"
UGCommand::UGCommand():
cmd_send_index(0),
cmd_recv_index(0),
prime_state(true)
{}
UGCommand::~UGCommand() {}
// calculate the nmea check sum
static char calc_nmea_cksum(const char *sentence) {
unsigned char sum = 0;
int i, len;
// cout << sentence << endl;
len = std::strlen(sentence);
sum = sentence[0];
for ( i = 1; i < len; i++ ) {
// cout << sentence[i];
sum ^= sentence[i];
}
// cout << endl;
// printf("sum = %02x\n", sum);
return sum;
}
// package and send the serial command
static int serial_send( SGSerialPort *serial, int sequence,
const string command )
{
char sequence_str[10];
snprintf( sequence_str, 9, "%d", sequence );
string package = sequence_str;
package += ",";
package += command;
char pkg_sum[10];
snprintf( pkg_sum, 3, "%02X", calc_nmea_cksum(package.c_str()) );
package += "*";
package += pkg_sum;
package += "\n";
unsigned int result = serial->write_port( package.c_str(),
package.length() );
if ( result != package.length() ) {
printf("ERROR: wrote %u of %u bytes to serial port!\n",
result, (unsigned)package.length() );
return 0;
}
return 1;
}
// send current command until acknowledged
int UGCommand::update( SGSerialPort *serial )
{
// if current command has been received, advance to next command
printf("sent = %d recv = %d\n", cmd_send_index, cmd_recv_index);
if ( cmd_recv_index >= cmd_send_index ) {
if ( ! cmd_queue.empty() ) {
if ( ! prime_state ) {
cmd_queue.pop();
cmd_send_index++;
} else {
prime_state = false;
}
}
}
// nothing to do if command queue empty
if ( cmd_queue.empty() ) {
prime_state = true;
return 0;
}
// send the command
string command = cmd_queue.front();
/*int result =*/ serial_send( serial, cmd_send_index, command );
return cmd_send_index;
}
void UGCommand::add( const string command )
{
printf("command queue: %s\n", command.c_str());
cmd_queue.push( command );
}
// create the global command channel manager
UGCommand command_mgr;