serial_timeouts.cpp

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/*****************************************************************************
** Platform Check
*****************************************************************************/

#include <ecl/config.hpp>
#if defined(ECL_IS_POSIX)

/*****************************************************************************
** Includes
*****************************************************************************/

#include <iostream>
#include <string>
#include <ecl/time/timestamp.hpp>
#include "../../include/ecl/devices/serial_pos.hpp"

/*****************************************************************************
** Namespaces
*****************************************************************************/

using namespace ecl;

/*****************************************************************************
** Functions
*****************************************************************************/

void print_usage() {
        std::cout << "Usage: demo_serial_timeouts [port]" << std::endl;
        std::cout << std::endl;
        std::cout << "  default value for port is /dev/ttyUSB0" << std::endl;
}

/*****************************************************************************
** Main
*****************************************************************************/

int main(int argc, char **argv) {

    std::string port("/dev/ttyUSB0");
    if ( argc > 1 ) {
        std::string arg(argv[1]);
        if ( arg == "--help" ) {
                print_usage();
                return 0;
        } else {
                port = argv[1];
        }
    }
    std::cout << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "               Serial Timeouts" << std::endl;
    std::cout << "***********************************************************" << std::endl;
        std::cout << "* For demo'ing low latency read timeouts on posix systems." << std::endl;
        std::cout << "* Timeouts < 100ms use a custom loop, > 100ms use termios." << std::endl;
        std::cout << "* Hook this up to a serial cable to test (actual" << std::endl;
        std::cout << "* connection not important)." << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << std::endl;

    Serial serial;
    try {
        serial.open(port,BaudRate_115200,DataBits_8,StopBits_1,NoParity);
    } catch (StandardException &e ) {
        std::cout << "[ERROR] : error opening " << port << std::endl;
        std::cout << std::endl;
        print_usage();
        return 0;
    }
    TimeStamp time, pre_read_time;
    char buffer[256];

    std::cout << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "                  100 ms timeouts" << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "* This will use termios to scan." << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << std::endl;

    serial.block(100);
    for ( unsigned int i = 0; i < 10; ++i ) {
        pre_read_time.stamp();
        long result = serial.read(buffer,256);
        time.stamp();
        if ( result > 0 ) {
                std::cout << "[INFO] : read " << result << " bytes." << std::endl;
        } else if ( result == 0 ) {
                std::cout << "[INFO] : timed out [" << (time - pre_read_time) << "]." << std::endl;
        } else {
                std::cout << "[INFO] : error " << result << "." << std::endl;
        }
    }

    std::cout << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "                  50 ms timeouts" << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "* This will internally scan with 5ms loops." << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << std::endl;

    serial.block(50);
    // uncomment this to test reading without a timeout on a loopback connection.
    // buffer[0] = 'a';
    // buffer[1] = 'b';
    // serial.write(buffer,2);
    for ( unsigned int i = 0; i < 10; ++i ) {
        pre_read_time.stamp();
        long result = serial.read(buffer,256);
        time.stamp();
        if ( result > 0 ) {
                std::cout << "[INFO] : read " << result << " bytes." << std::endl;
        } else if ( result == 0 ) {
                std::cout << "[INFO] : timed out [" << (time - pre_read_time) << "]." << std::endl;
        } else {
                std::cout << "[INFO] : error " << result << "." << std::endl;
        }
    }
    std::cout << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "                  20 ms timeouts" << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "* This will internally scan with 2ms loops." << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << std::endl;

    serial.block(20);
    for ( unsigned int i = 0; i < 10; ++i ) {
        pre_read_time.stamp();
        long result = serial.read(buffer,256);
        time.stamp();
        if ( result > 0 ) {
                std::cout << "[INFO] : read " << result << " bytes." << std::endl;
        } else if ( result == 0 ) {
                std::cout << "[INFO] : timed out [" << (time - pre_read_time) << "]." << std::endl;
        } else {
                std::cout << "[INFO] : error " << result << "." << std::endl;
        }
    }
    std::cout << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "                  5 ms timeouts" << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << "* This will internally scan with 1ms loops." << std::endl;
    std::cout << "***********************************************************" << std::endl;
    std::cout << std::endl;

    serial.block(5);
    for ( unsigned int i = 0; i < 10; ++i ) {
        pre_read_time.stamp();
        long result = serial.read(buffer,256);
        time.stamp();
        if ( result > 0 ) {
                std::cout << "[INFO] : read " << result << " bytes." << std::endl;
        } else if ( result == 0 ) {
                std::cout << "[INFO] : timed out [" << (time - pre_read_time) << "]." << std::endl;
        } else {
                std::cout << "[INFO] : error " << result << "." << std::endl;
        }
    }
    return 0;
}

#else

/*****************************************************************************
** Main
*****************************************************************************/

int main(int argc, char **argv) {

        std::cout << "This demo is only for testing low latency blocking timeouts" << std::endl;
        std::cout << "on on posix systems." << std::endl;

        return 0;
}

#endif