/*
 * fill and process an input buffer
 *	called only when fp->_cnt < 0
 *
 * more hacks, the initial impl bit!
 *
 *	++jrb	bammi@dsrgsun.ces.cwru.edu
 *
 * do not remember EOF if input comes from a tty (er)
 *
 */


#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <memory.h>
#include "lib.h"

#ifdef __GNUC__
#define alloca __builtin_alloca
#endif

int _filbuf(fp)
FILE *fp;
{
    register unsigned int f;
    register long got;
    
    f = fp->_flag;
    if(f & _IORW) f = (fp->_flag |= _IOREAD);
    if(!(f & _IOREAD) || (f & (_IOERR | _IOEOF)))
	return(EOF);

    /* if this is stdin &  a tty, and stdout is line buffered, flush it */
    if((fp == stdin) && (f & _IODEV) && (stdout->_flag & _IOLBF))
	(void)fflush(stdout);

    fp->_ptr = fp->_base;
    if((got = _read(fp->_file, fp->_base, (long)fp->_bsiz)) <= 0)
    {   /* EOF or error */
	fp->_flag |= ((got == 0) ? ((f & _IODEV) ? 0 : _IOEOF) : _IOERR);
	return EOF;
    }
    fp->_cnt = got - 1;
    return *(fp->_ptr)++;
}