c_dfe.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char	*sccsid = " @(#)c_dfe.c	4.1	(ULTRIX)	7/3/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1986 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
*
*			Modification History
*
*	David Metsky		10-Jan-86
*
* 001	Version added from BSD 4.3 version as part of upgrade.
*
*	Based on:	c_dfe.c		5.2		7/30/85
*
*************************************************************************/

/*
 * direct formatted external i/o - common read/write routines
 */

#include "fio.h"

c_dfe(a,flag,str) cilist *a; char *str;
{	int n;
	sequential = NO;
	external = YES;
	formatted = FORMATTED;
	lfname = NULL;
	elist = NO;
	cursor=scale=recpos=reclen=0;
	radix = 10;
	signit = YES;
	fmtbuf = a->cifmt;
	errflag = a->cierr;
	endflag = a->ciend;
	lunit = a->ciunit;
	if(not_legal(lunit)) err(errflag,F_ERUNIT,str);
	curunit = &units[lunit];
	if(!curunit->ufd && (n=fk_open(flag,DIR,FMT,(ftnint)lunit)))
		err(errflag,n,str)
	cf = curunit->ufd;
	elist = YES;
	lfname = curunit->ufnm;
	if(!curunit->ufmt) err(errflag,F_ERNOFIO,str)
	if(!curunit->useek || !curunit->url) err(errflag,F_ERNODIO,str)
	recnum = a->cirec - 1;
	fseek(cf, (long)curunit->url * recnum, 0);
	cblank = curunit->ublnk;
	cplus = NO;
	return(OK);
}

y_tab()
{	int n;
	if(curunit->url==1)
	{
		if(cursor < 0 && -cursor > ftell(cf)) rewind(cf);
		else	fseek(cf,(long)cursor,1);
		return(cursor=0);
	}
	else
	{	if(reclen < recpos) reclen = recpos;
		if((recpos + cursor) < 0) cursor = -recpos;	/* BOR */
		n = reclen - recpos;		/* n >= 0 */
		if(!reading && (cursor-n) > 0)
		{	recpos = reclen;
			cursor -= n;
			fseek(cf,(long)n,1);
			while(cursor--) if(n=(*putn)(' ')) return(n);
			return(cursor=0);
		}
		recpos += cursor;
		if(recpos >= curunit->url) err(errflag,F_EREREC,"dfe")
	}
	fseek(cf,(long)cursor,1);
	return(cursor=0);
}