/*
 *
 *	Copyright (C) 1988, 1989 by the Massachusetts Institute of Technology
 *    	Developed by the MIT Student Information Processing Board (SIPB).
 *    	For copying information, see the file mit-copyright.h in this release.
 *
 */
/*
 *
 *	$Source: /afs/sipb.mit.edu/project/discuss/.cvsroot/discuss/source/libds/tfile.c,v $
 *	$Header: /afs/sipb.mit.edu/project/discuss/.cvsroot/discuss/source/libds/tfile.c,v 1.7 1994/09/19 03:47:05 raeburn Exp $
 *
 * tfile.c -- a new implementation of tfile's.
 *
 *	$Log: tfile.c,v $
 * Revision 1.7  1994/09/19  03:47:05  raeburn
 * tcreate first arg is now an off_t
 *
 * Revision 1.6  1992/06/26 02:18:57  raeburn
 * getting in sync with current source tree
 *
 * Revision 1.5  89/06/03  00:22:07  srz
 * Added standard copyright notice.
 * 
 * Revision 1.4  89/06/03  00:12:58  srz
 * Ken's changes.
 * 
 * Revision 1.3  87/07/18  00:01:19  srz
 * Added control operation to tfile's.
 * 
 * Revision 1.2  87/04/11  00:06:21  srz
 * Added RCS junk
 * 
 *
 */
#ifndef lint
static char rcsid_tfile_c[] =
    "$Header: /afs/sipb.mit.edu/project/discuss/.cvsroot/discuss/source/libds/tfile.c,v 1.7 1994/09/19 03:47:05 raeburn Exp $";
#endif lint

#include <stdio.h>
#include <errno.h>
#include <discuss/tfile.h>
#include <sys/types.h>
#include <sys/stat.h>

#define min(A, B) ((A) < (B) ? (A) : (B))
#define NIL 0
#define SUCCESS 1

extern char *malloc ();
extern int errno;

tfile tcreate (tfs, infop, info, proc)
     off_t tfs;
     char *infop;
     int info;
     int (*proc)();
{
     tfile tf;

     tf = (tfile) malloc (sizeof (struct _tfile));
     if (tf ==  NIL)
	  return (NIL);

     tf -> proc = proc;
     tf -> size = tfs;
     tf -> info = info;
     tf -> infop = infop;

     return (tf);
}

/*
 *
 * tfsize (tf)  -- return size of a file.
 *
 */
int tfsize (tf)
tfile tf;
{
     return (tf -> size);
}

topen(tf,mode,result)
tfile tf;
char *mode;
int *result;
{
     if (tf == NIL || tf -> proc == NIL) {
	  *result = EINVAL;
	  return (-1);
     }

     return ((*(tf -> proc)) (TFOPEN, &(tf -> infop), &(tf -> info), mode, 0, result));

}

tclose(tf,result)
tfile tf;
int *result;
{
     if (tf == NIL || tf -> proc == NIL) {
	  *result = EINVAL;
	  return (-1);
     }

     return ((*(tf -> proc)) (TFCLOSE, &(tf -> infop), &(tf -> info), 0, 0, result));
}

int tread(tf,bufp,wanted,result)
tfile tf;
char *bufp;
int wanted;
int *result;
{
     if (tf == NIL || tf -> proc == NIL) {
	  *result = EINVAL;
	  return (-1);
     }

     return ((*(tf -> proc)) (TFREAD, &(tf -> infop), &(tf -> info), bufp, wanted,result));
}

int twrite(tf,bufp,wanted,result)
tfile tf;
char *bufp;
int wanted;
int *result;
{
     if (tf == NIL || tf -> proc == NIL) {
	  *result = EINVAL;
	  return (-1);
     }

     return ((*(tf -> proc)) (TFWRITE, &(tf -> infop), &(tf -> info), bufp, wanted, result));
}

int tcontrol(tf,op,cinfop,result)
tfile tf;
int op;
char *cinfop;
int *result;
{
     if (tf == NIL || tf -> proc == NIL) {
	  *result = EINVAL;
	  return (-1);
     }

     return ((*(tf -> proc)) (TFCONTROL, &(tf -> infop), &(tf -> info), cinfop, op, result));
}

int tdestroy (tf)
tfile tf;
{
     int dummy;

     if (tf == NIL) {
	  return (-1);
     }

     if (tf -> proc != NIL)
	  (void) (*(tf -> proc)) (TFDESTROY, &(tf -> infop), &(tf -> info), 0, 0, &dummy);
     tf -> proc = NIL;
     free (tf);

     return(0);
}