#include <cstdlib>

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

#include "rs232.h"


typedef unsigned char byte;

    Comm::CommStatus Comm::open()
    {
        fd = ::open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
        if (-1 == fd) return COMM_ERR;
        
        struct termios options;
        tcgetattr(fd, &options);
    
        tcflush(fd, TCIFLUSH);
        options.c_cflag = CBAUD | B9600 | CS8 | CREAD | CLOCAL;
        options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
        options.c_iflag &= ~(INPCK | ISTRIP);
        options.c_iflag &= ~(IXON | IXOFF | IXANY);
        options.c_oflag &= ~OPOST;
    
        cfsetispeed(&options, B9600);
        cfsetospeed(&options, B9600);

        tcsetattr(fd, TCSANOW, &options);
        
        return COMM_OK;
    }
    
    Comm::CommStatus Comm::send(const byte *const data, const unsigned len)
    {
        int status = ::write(fd, data, len);
        
        if (status < 0) return COMM_ERR;
        else return COMM_OK;
    }
    
    Comm::CommStatus Comm::recvbyte(byte *const data)
    {
        int status = ::read(fd, data, 1);
        
        if (status < 0 && errno == EAGAIN) return COMM_NULL;
        else if(status < 0) return COMM_ERR;
        return COMM_OK;
    }
    
    Comm::CommStatus Comm::recv(byte* data, int size)
    {
        CommStatus st = recvbyte(data);
        if (st != COMM_OK) return st;        
        if (1 == size--)   return st;
        
        fcntl(fd, F_SETFL, 0);
        
        while (size-- > 0)
        {
            st = recvbyte(++data);
            if (st != COMM_OK) break;
        }
        
        fcntl(fd, F_SETFL, FNDELAY);
        return st;
    }