xdr_stdio.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

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

/*
 * xdr_stdio.c, XDR implementation on standard i/o file.
 *
 *
 * This set of routines implements a XDR on a stdio stream.
 * XDR_ENCODE serializes onto the stream, XDR_DECODE de-serializes
 * from the stream.
 */

#include <rpc/types.h>
#include <stdio.h>
#include <rpc/xdr.h>

static bool_t	xdrstdio_getlong();
static bool_t	xdrstdio_putlong();
static bool_t	xdrstdio_getbytes();
static bool_t	xdrstdio_putbytes();
static u_int	xdrstdio_getpos();
static bool_t	xdrstdio_setpos();
static long *	xdrstdio_inline();
static void	xdrstdio_destroy();

/*
 * Ops vector for stdio type XDR
 */
static struct xdr_ops	xdrstdio_ops = {
	xdrstdio_getlong,	/* deseraialize a long int */
	xdrstdio_putlong,	/* seraialize a long int */
	xdrstdio_getbytes,	/* deserialize counted bytes */
	xdrstdio_putbytes,	/* serialize counted bytes */
	xdrstdio_getpos,	/* get offset in the stream */
	xdrstdio_setpos,	/* set offset in the stream */
	xdrstdio_inline,	/* prime stream for inline macros */
	xdrstdio_destroy	/* destroy stream */
};

/*
 * Initialize a stdio xdr stream.
 * Sets the xdr stream handle xdrs for use on the stream file.
 * Operation flag is set to op.
 */
void
xdrstdio_create(xdrs, file, op)
	register XDR *xdrs;
	FILE *file;
	enum xdr_op op;
{

	xdrs->x_op = op;
	xdrs->x_ops = &xdrstdio_ops;
	xdrs->x_private = (caddr_t)file;
	xdrs->x_handy = 0;
	xdrs->x_base = 0;
}

/*
 * Destroy a stdio xdr stream.
 * Cleans up the xdr stream handle xdrs previously set up by xdrstdio_create.
 */
static void
xdrstdio_destroy(xdrs)
	register XDR *xdrs;
{
	(void)fflush((FILE *)xdrs->x_private);
	/* xx should we close the file ?? */
};

static bool_t
xdrstdio_getlong(xdrs, lp)
	XDR *xdrs;
	register long *lp;
{

	if (fread((caddr_t)lp, sizeof(long), 1, (FILE *)xdrs->x_private) != 1)
		return (FALSE);
#ifndef mc68000
	*lp = ntohl(*lp);
#endif
	return (TRUE);
}

static bool_t
xdrstdio_putlong(xdrs, lp)
	XDR *xdrs;
	long *lp;
{

#ifndef mc68000
	long mycopy = htonl(*lp);
	lp = &mycopy;
#endif
	if (fwrite((caddr_t)lp, sizeof(long), 1, (FILE *)xdrs->x_private) != 1)
		return (FALSE);
	return (TRUE);
}

static bool_t
xdrstdio_getbytes(xdrs, addr, len)
	XDR *xdrs;
	caddr_t addr;
	u_int len;
{

	if ((len != 0) && (fread(addr, (int)len, 1, (FILE *)xdrs->x_private) != 1))
		return (FALSE);
	return (TRUE);
}

static bool_t
xdrstdio_putbytes(xdrs, addr, len)
	XDR *xdrs;
	caddr_t addr;
	u_int len;
{

	if ((len != 0) && (fwrite(addr, (int)len, 1, (FILE *)xdrs->x_private) != 1))
		return (FALSE);
	return (TRUE);
}

static u_int
xdrstdio_getpos(xdrs)
	XDR *xdrs;
{

	return ((u_int) ftell((FILE *)xdrs->x_private));
}

static bool_t
xdrstdio_setpos(xdrs, pos) 
	XDR *xdrs;
	u_int pos;
{ 

	return ((fseek((FILE *)xdrs->x_private, (long)pos, 0) < 0) ?
		FALSE : TRUE);
}

static long *
xdrstdio_inline(xdrs, len)
	XDR *xdrs;
	u_int len;
{

	/*
	 * Must do some work to implement this: must insure
	 * enough data in the underlying stdio buffer,
	 * that the buffer is aligned so that we can indirect through a
	 * long *, and stuff this pointer in xdrs->x_buf.  Doing
	 * a fread or fwrite to a scratch buffer would defeat
	 * most of the gains to be had here and require storage
	 * management on this buffer, so we don't do this.
	 */
	return (NULL);
}