FDIOStream.cpp

/*
 * FDIOStream.cpp
 *
 *  Created on: Sep 27, 2012
 *      Author: Mitchell Wills
 */

#include "networktables2/stream/FDIOStream.h"
#include "networktables2/util/IOException.h"
#include "networktables2/util/EOFException.h"

#include <errno.h>
#include <stdlib.h>
#include <iolib.h>
#include <selectLib.h>
#include <string.h>
#include <stdio.h>


FDIOStream::FDIOStream(int _fd){
  fd = _fd;
  //    f = fdopen(_fd, "rbwb");
  //    if(f==NULL)
  //            throw IOException("Could not open stream from file descriptor", errno);
}
FDIOStream::~FDIOStream(){
        close();
}

int FDIOStream::read(void* ptr, int numbytes){
        if(numbytes==0)
                return 0;
        char* bufferPointer = (char*)ptr;
        int totalRead = 0;

        struct timeval timeout;
        fd_set fdSet;
        
        while (totalRead < numbytes) {
                FD_ZERO(&fdSet);
                FD_SET(fd, &fdSet);
                timeout.tv_sec = 1;
                timeout.tv_usec = 0;
                int select_result = select(FD_SETSIZE, &fdSet, NULL, NULL, &timeout);
                if ( select_result < 0)
                  throw IOException("Select returned an error on read");

                int numRead = 0;
                if (FD_ISSET(fd, &fdSet)) {
                  numRead = ::read(fd, bufferPointer, numbytes-totalRead);

                  if(numRead == 0){
                    throw EOFException();
                  }
                  else if (numRead < 0) {
                    perror("read error: ");
                    fflush(stderr);
                    throw IOException("Error on FDIO read");
                  }
                  bufferPointer += numRead;
                  totalRead += numRead;
                }
        }
        return totalRead;
}
int FDIOStream::write(const void* ptr, int numbytes){
  int numWrote = ::write(fd, (char*)ptr, numbytes);//TODO: this is bad
  //int numWrote = fwrite(ptr, 1, numbytes, f);
  if(numWrote==numbytes)
    return numWrote;
  perror("write error: ");
  fflush(stderr);
  throw IOException("Could not write all bytes to fd stream");
        
}
void FDIOStream::flush(){
  //if(fflush(f)==EOF)
  //  throw EOFException();
}
void FDIOStream::close(){
  //fclose(f);//ignore any errors closing
  ::close(fd);
}