xdr_reference.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static char *sccsid = "@(#)xdr_reference.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.	*
 *									*
 ************************************************************************/

/*
 *	Portions of this software have been licensed to 
 *	Digital Equipment Company, Maynard, MA.
 *	Copyright (c) 1986 Sun Microsystems, Inc.  ALL RIGHTS RESERVED.
 */
/*	Change Log
 *	04/13/89	jhw	Picked up SUN 4.0 changes
 */

/*
 * xdr_reference.c, Generic XDR routines impelmentation.
 *
 *
 * These are the "non-trivial" xdr primitives used to serialize and de-serialize
 * "pointers".  See xdr.h for more info on the interface to xdr.
 */

#ifdef KERNEL
#include "../h/param.h"
#include "../rpc/types.h"
#include "../rpc/xdr.h"
#else
#include <rpc/types.h>
#include <rpc/xdr.h>
#include <stdio.h>
#endif
#define LASTUNSIGNED	((u_int)0-1)


/*
 * XDR an indirect pointer
 * xdr_reference is for recursively translating a structure that is
 * referenced by a pointer inside the structure that is currently being
 * translated.  pp references a pointer to storage. If *pp is null
 * the  necessary storage is allocated.
 * size is the sizeof the referneced structure.
 * proc is the routine to handle the referenced structure.
 */
bool_t
xdr_reference(xdrs, pp, size, proc)
	register XDR *xdrs;
	caddr_t *pp;		/* the pointer to work on */
	u_int size;		/* size of the object pointed to */
	xdrproc_t proc;		/* xdr routine to handle the object */
{
	register caddr_t loc = *pp;
	register bool_t stat;

	if (loc == NULL)
		switch (xdrs->x_op) {
		case XDR_FREE:
			return (TRUE);

		case XDR_DECODE:
			*pp = loc = (caddr_t)mem_alloc(0, 0, size, 0);
#ifndef KERNEL
			if (loc == NULL) {
				fprintf(stderr,
				    "xdr_reference: out of memory\n");
				return (FALSE);
			}
#endif
			bzero(loc, (int)size);
			break;
	}

	stat = (*proc)(xdrs, loc, LASTUNSIGNED);

	if (xdrs->x_op == XDR_FREE) {
		mem_free(loc, size);
		*pp = NULL;
	}
	return (stat);
}
#ifndef KERNEL
/*
 * xdr_pointer():
 *
 * XDR a pointer to a possibly recursive data structure. This
 * differs with xdr_reference in that it can serialize/deserialiaze
 * trees correctly.
 *
 *  What's sent is actually a union:
 *
 *  union object_pointer switch (boolean b) {
 *  case TRUE: object_data data;
 *  case FALSE: void nothing;
 *  }
 *
 * > objpp: Pointer to the pointer to the object.
 * > obj_size: size of the object.
 * > xdr_obj: routine to XDR an object.
 *
 */
bool_t
xdr_pointer(xdrs,objpp,obj_size,xdr_obj)
               register XDR *xdrs;
        char **objpp;
        u_int obj_size;
        xdrproc_t xdr_obj;
{

        bool_t more_data;

        more_data = (*objpp != NULL);
        if (! xdr_bool(xdrs,&more_data)) {
                return (FALSE);
        }
        if (! more_data) {
                *objpp = NULL;
                return (TRUE);
        }
        return (xdr_reference(xdrs,objpp,obj_size,xdr_obj));
}
#endif /* ! KERNEL */