#include "f2c.h"
#include "fio.h"

#ifdef KR_headers
c_due(a) cilist *a;
#else
c_due(cilist *a)
#endif
{
	if(f__init != 1) f_init();
	f__init = 3;
	if(a->ciunit>=MXUNIT || a->ciunit<0)
		err(a->cierr,101,"startio");
	f__sequential=f__formatted=f__recpos=0;
	f__external=1;
	f__curunit = &f__units[a->ciunit];
	f__elist=a;
	if(f__curunit->ufd==NULL && fk_open(DIR,UNF,a->ciunit) ) err(a->cierr,104,"due");
	f__cf=f__curunit->ufd;
	if(f__curunit->ufmt) err(a->cierr,102,"cdue");
	if(!f__curunit->useek) err(a->cierr,104,"cdue");
	if(f__curunit->ufd==NULL) err(a->cierr,114,"cdue");
	if(a->cirec <= 0)
		err(a->cierr,130,"due");
	(void) fseek(f__cf,(long)(a->cirec-1)*f__curunit->url,SEEK_SET);
	f__curunit->uend = 0;
	return(0);
}
#ifdef KR_headers
integer s_rdue(a) cilist *a;
#else
integer s_rdue(cilist *a)
#endif
{
	int n;
	f__reading=1;
	if(n=c_due(a)) return(n);
	if(f__curunit->uwrt && f__nowreading(f__curunit))
		err(a->cierr,errno,"read start");
	return(0);
}
#ifdef KR_headers
integer s_wdue(a) cilist *a;
#else
integer s_wdue(cilist *a)
#endif
{
	int n;
	f__reading=0;
	if(n=c_due(a)) return(n);
	if(f__curunit->uwrt != 1 && f__nowwriting(f__curunit))
		err(a->cierr,errno,"write start");
	return(0);
}
integer e_rdue(Void)
{
	f__init = 1;
	if(f__curunit->url==1 || f__recpos==f__curunit->url)
		return(0);
	(void) fseek(f__cf,(long)(f__curunit->url-f__recpos),SEEK_CUR);
	if(ftell(f__cf)%f__curunit->url)
		err(f__elist->cierr,200,"syserr");
	return(0);
}
integer e_wdue(Void)
{
	f__init = 1;
#ifdef ALWAYS_FLUSH
	if (fflush(f__cf))
		err(f__elist->cierr,errno,"write end");
#endif
	return(e_rdue());
}
