#include	"defs.h"

/*
 * input library
 *
 * S. R. Bourne
 * Bell Telephone Laboratories
 *
 */

FILE		_infile;
FILEPTR		standin = &_infile;


readc()
{
	REG INT		c;
	REG INT		len;
	REG FILEPTR	f;

retry:
	IF f=standin, f->fnxt!=f->fend
	THEN	c = *f->fnxt++;
		IF c==NL THEN f->flin++; FI
	ELIF (f->fstatus&F_EOF) ORF f->fdes<0
	THEN	c=EOF; f->fstatus |= F_EOF;
	ELIF (len=read(f->fdes,f->fbuf,f->fsiz))==0
	THEN	close(f->fdes); f->fdes = -1; c=EOF; f->fstatus |= F_EOF;
	ELSE	f->fend = (f->fnxt = f->fbuf)+len;
		IF len<0
		THEN	return(c=NL);
		ELSE	goto retry;
		FI
	FI
	return(c);
}

backspace(f)
	FILEPTR f;
{
	IF (f->fend <= f->fbuf) ORF (f->fnxt <= f->fbuf)
	THEN	abend("backspace");
	ELIF (*--f->fnxt)==NL THEN f->flin--;
	FI
}