#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/poll.h>

#include "ioutils.h"

 
int writeall(int fd, const void *b, int len)
{
  int cnt=0;
  int thiscnt;
  unsigned char *bb=(unsigned char*) b;

  while (cnt<len)
    {
      thiscnt=write(fd, &bb[cnt], len-cnt);
      if (thiscnt<0)
	return -1;
      cnt+=thiscnt;
    }

  return cnt;
}

int readtimeout(int fd, void *buf, int maxlen, int msTimeout)
{
  struct pollfd pfd;
  int len;
  int res;
                                                                                             
  pfd.fd=fd;
  pfd.events=POLLIN;
                                                                                             
  res=poll(&pfd, 1, msTimeout);
  if (res<0) // error
    {
      perror("poll");
      return 0;
    }
  if (res==0) // timeout
    {
      errno=ETIMEDOUT;
      return 0;
    }
                                                                                             
  len=read(fd, buf, maxlen);
  if (len<0)
    {
      perror("read");
      len=0;
    }
                                                                                             
  return len;
}

int readfullytimeout(int fd, void *bufin, int len, int msTimeout)
{
  char *buf=(char*) bufin;
  int readsofar=0;
  int thisread=0;

  while (readsofar<len)
    {
      thisread=readtimeout(fd, &buf[readsofar], len-readsofar, msTimeout);
      if (thisread<=0)
	return 0;

      readsofar+=thisread;
    }

  return len;
}
                                                                                             
// reads number of bytes available, <0 on error.
int readavailable(int fd)
{
  long avail = 0;
                                                                                             
  if(ioctl(fd, FIONREAD, &avail) == 0)
    return avail;
  else
    return -1;
}
                                                                                            
// read (and discard) all available data.
void readflush(int fd)
{
  int avail;
  char buf[1024];
                                                                                             
  do
    {
      avail=readavailable(fd);
      if (avail>1024)
        avail=1024;
                                                                                             
      read(fd, buf, avail);
    } while (avail>0);
                                                                                             
}

// returns length of string, 0 on error.
int readlinetimeout(int fd, void *buf_in, int maxlen, int msTimeout)
{
  int len=0;
  int thislen;
  char *buf=(char*) buf_in;

  while (len<maxlen)
    {
      thislen=readtimeout(fd, &buf[len], 1, msTimeout);
      if (thislen<=0)
        return 0;
                                                                                             
      if (buf[len]=='\n' || buf[len]=='\r')
        {
          buf[len]=0;
          return len;
        }
                                                                                             
      len++;
    }
                                                                                             
  buf[len]=0;
  return len;
}