/*
 * xdr_sizeof.c
 *
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *     * Neither the name of the "Oracle America, Inc." nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * General purpose routine to see how much space something will use
 * when serialized using XDR.
 */

#include <rpc/types.h>
#include <rpc/xdr.h>
#include <sys/types.h>
#include <stdlib.h>

/* ARGSUSED */
static bool_t
x_putlong (XDR *xdrs, const long *longp)
{
  xdrs->x_handy += BYTES_PER_XDR_UNIT;
  return TRUE;
}

/* ARGSUSED */
static bool_t
x_putbytes (XDR *xdrs, const char *bp, u_int len)
{
  xdrs->x_handy += len;
  return TRUE;
}

static u_int
x_getpostn (const XDR *xdrs)
{
  return xdrs->x_handy;
}

/* ARGSUSED */
static bool_t
x_setpostn (XDR *xdrs, u_int len)
{
  /* This is not allowed */
  return FALSE;
}

static int32_t *
x_inline (XDR *xdrs, u_int len)
{
  if (len == 0)
    return NULL;
  if (xdrs->x_op != XDR_ENCODE)
    return NULL;
  if (len < (u_int) (long int) xdrs->x_base)
    {
      /* x_private was already allocated */
      xdrs->x_handy += len;
      return (int32_t *) xdrs->x_private;
    }
  else
    {
      /* Free the earlier space and allocate new area */
      free (xdrs->x_private);
      if ((xdrs->x_private = (caddr_t) malloc (len)) == NULL)
	{
	  xdrs->x_base = 0;
	  return NULL;
	}
      xdrs->x_base = (void *) (long) len;
      xdrs->x_handy += len;
      return (int32_t *) xdrs->x_private;
    }
}

static int
harmless (void)
{
  /* Always return FALSE/NULL, as the case may be */
  return 0;
}

static void
x_destroy (XDR *xdrs)
{
  xdrs->x_handy = 0;
  xdrs->x_base = 0;
  if (xdrs->x_private)
    {
      free (xdrs->x_private);
      xdrs->x_private = NULL;
    }
  return;
}

static bool_t
x_putint32 (XDR *xdrs, const int32_t *int32p)
{
  xdrs->x_handy += BYTES_PER_XDR_UNIT;
  return TRUE;
}

unsigned long
xdr_sizeof (xdrproc_t func, void *data)
{
  XDR x;
  struct xdr_ops ops;
  bool_t stat;
  /* to stop ANSI-C compiler from complaining */
  typedef bool_t (*dummyfunc1) (XDR *, long *);
  typedef bool_t (*dummyfunc2) (XDR *, caddr_t, u_int);
  typedef bool_t (*dummyfunc3) (XDR *, int32_t *);

  ops.x_putlong = x_putlong;
  ops.x_putbytes = x_putbytes;
  ops.x_inline = x_inline;
  ops.x_getpostn = x_getpostn;
  ops.x_setpostn = x_setpostn;
  ops.x_destroy = x_destroy;
  ops.x_putint32 = x_putint32;

  /* the other harmless ones */
  ops.x_getlong = (dummyfunc1) harmless;
  ops.x_getbytes = (dummyfunc2) harmless;
  ops.x_getint32 = (dummyfunc3) harmless;

  x.x_op = XDR_ENCODE;
  x.x_ops = &ops;
  x.x_handy = 0;
  x.x_private = (caddr_t) NULL;
  x.x_base = (caddr_t) 0;

  stat = func (&x, data);
  free (x.x_private);
  return stat == TRUE ? x.x_handy : 0;
}