Skip to content

Instantly share code, notes, and snippets.

@zguangyu

zguangyu/serial.cpp

Created January 24, 2015 11:59
Show Gist options

  • Select an option

    Learn more about clone URLs
  • Save zguangyu/c93f28c952e8acc710c1 to your computer and use it in GitHub Desktop.

Select an option

Learn more about clone URLs
Save zguangyu/c93f28c952e8acc710c1 to your computer and use it in GitHub Desktop.
Download ZIP

Revisions

  1. zguangyu created this gist Jan 24, 2015.
    142 changes: 142 additions & 0 deletions serial.cpp
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,142 @@
    #include <cstring>
    #include <cerrno>
    #include <cstdio>

    #include <iostream>
    #include <deque>
    #include <vector>
    #include <thread>
    #include <mutex>
    #include <chrono>
    #include <algorithm>
    #include <functional>
    #include <cctype>
    #include <locale>

    #include <termios.h>
    #include <unistd.h>
    #include <fcntl.h>
    #include <sys/stat.h>
    #include <sys/types.h>

    #include "serial.h"

    using namespace std;

    mutex fifo_mutex;

    static inline std::string &ltrim(std::string &s) {
    s.erase(s.begin(), std::find_if(s.begin(), s.end(), std::not1(std::ptr_fun<int, int>(std::isspace))));
    return s;
    }

    static inline std::string &rtrim(std::string &s) {
    s.erase(std::find_if(s.rbegin(), s.rend(), std::not1(std::ptr_fun<int, int>(std::isspace))).base(), s.end());
    return s;
    }

    static inline std::string &trim(std::string &s) {
    return ltrim(rtrim(s));
    }

    Serial::Serial (string portname, int speed, int parity) : messages(0)
    {
    fd = open (portname.c_str(), O_RDWR | O_NOCTTY | O_SYNC);
    if (fd < 0) {
    fprintf(stderr, "Error opening serial port %s\n", portname.c_str());
    return;
    }

    struct termios tty;
    memset (&tty, 0, sizeof tty);
    if (tcgetattr(fd, &tty) != 0) {
    fprintf(stderr, "Error %d from tcgetattr: %s\n", errno, strerror(errno));
    return;
    }

    cfsetospeed (&tty, speed);
    cfsetispeed (&tty, speed);

    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;
    tty.c_iflag &= ~IGNBRK;
    tty.c_lflag = 0;
    tty.c_oflag = 0;
    tty.c_cc[VMIN] = 1;
    tty.c_cc[VTIME] = 5;

    tty.c_iflag &= ~(IXON | IXOFF | IXANY);
    tty.c_cflag |= (CLOCAL | CREAD);
    tty.c_cflag &= ~(PARENB | PARODD);
    tty.c_cflag |= parity;
    tty.c_cflag &= ~CSTOPB;
    tty.c_cflag &= ~CRTSCTS;

    if (tcsetattr (fd, TCSANOW, &tty) != 0) {
    fprintf(stderr, "Error %d from tcsetattr: %s\n", errno, strerror(errno));
    }
    }

    void Serial::readPort()
    {
    if (fd<0)
    return;

    vector<char> v(100);
    int n = read(fd, &v[0], 100);
    v.resize(n);

    fifo_mutex.lock();
    for (auto i : v) {
    fifo.push_back(i);
    if (i == '#')
    messages++;
    }
    fifo_mutex.unlock();
    }

    void Serial::writePort(vector<char> &v)
    {
    if (fd<0)
    return;

    int n = write(fd, &v[0], v.size());
    if (n < 0)
    cerr << "Write error" << endl;
    }

    string Serial::getMessage()
    {
    if (messages <= 0)
    return "";

    deque<char>::iterator iter = fifo.begin();
    while(*iter != '#')
    iter++;

    string s(fifo.begin(), iter);

    iter++;

    fifo_mutex.lock();
    fifo.erase(fifo.begin(), iter);
    messages--;
    fifo_mutex.unlock();
    cout << '"' << trim(s) << '"' << endl;
    return s;
    }

    int main()
    {
    Serial s("/dev/ttyS1", B9600, 0);
    thread t([&s](){
    while (1) {
    s.readPort();
    this_thread::sleep_for(chrono::milliseconds(200));
    }
    });
    while (1) {
    sleep(1);
    while (s.getMessage() != "");
    }
    return 0;
    }
    17 changes: 17 additions & 0 deletions serial.h
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,17 @@
    #include <deque>
    #include <vector>

    using namespace std;

    class Serial
    {
    public:
    deque<char> fifo;
    int messages;
    Serial(string portname, int speed, int parity);
    void readPort();
    void writePort(vector<char> &v);
    string getMessage();
    private:
    int fd;
    };