read.c

接收Fax的程序

/*
** (c) 1992 Uwe C. Schroeder, Anwendungssysteme , Augsburg, Germany
**
** 
** Permission to use, copy, and modify this software and its
** documentation for non comercial  purpose is hereby granted 
** without fee, provided that
** the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation, and that the name of Uwe C. Schroeder not be used in
** advertising or publicity pertaining to distribution of the software without
** specific, written prior permission.  Uwe Schroeder makes no representations
** about the suitability of this software for any purpose.  It is provided
** "as is" without express or implied warranty.
** This software may not be sold or distributed with commercial products
** ( this includes distribution "for users convenience" ) without prior
** written permission by the author.
**
** UWE SCHROEDER DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
** INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
** EVENT SHALL UWE SCHROEDER BE LIABLE FOR ANY SPECIAL, INDIRECT OR
** CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
** DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
** TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
** PERFORMANCE OF THIS SOFTWARE.
**
**
** This is a alpha release, which means, that there are still several
** known bugs.
**
** Please report bugs to:
**
**                     [e-mail]
**
*/


#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>

#include "vfax.h"
extern int fd;

/* reads a line of characters, terminated by a newline */
/* returns number ob chars read (w/o zero) */
int fdgets(buf, nbytes)
     char *buf;
     int nbytes;
{
  int i;
  char *bp;
  unsigned char ch;
  
 again:
  bp = buf;
  for (i = 0; i < nbytes; i++) {
    while(read(fd,&ch,1) < 1);
    if (ch == '\n' || ch == '\r') break;
    *bp++ = ch;
  }
  
  if(i<2) goto again;
  *bp = '\0';
  return(i);
}

/* read with hang on tty line 
   this works only in blocked read mode &~O_NDELAY
*/

int
read_hang(buf,bytes)
     int bytes;
     char *buf;
{
  int i;
  char *bp;
  unsigned char ch;
  
  bp = buf;
  
  for (i = 0; i < bytes; i++) {
    if(read(fd,&ch,1)>0)
      *bp++ = ch;
    else
      goto end;
  }
 end:
  return(i);
}