/* @(#)xdr_mem.c	2.1 88/07/29 4.0 RPCSRC */
/*
 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 *
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 *
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 *
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 *
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 *
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */
#if !defined(lint) && defined(SCCSIDS)
static char sccsid[] = "@(#)xdr_mem.c 1.19 87/08/11 Copyr 1984 Sun Micro";
#endif

/*
 * xdr_mem.h, XDR implementation using memory buffers.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * If you have some data to be interpreted as external data representation
 * or to be converted to external data representation in a memory buffer,
 * then this is the package for you.
 *
 */


#include <string.h>
#include <rpc/rpc.h>

static bool_t xdrmem_getlong (XDR *, long *);
static bool_t xdrmem_putlong (XDR *, const long *);
static bool_t xdrmem_getbytes (XDR *, caddr_t, u_int);
static bool_t xdrmem_putbytes (XDR *, const char *, u_int);
static u_int xdrmem_getpos (const XDR *);
static bool_t xdrmem_setpos (XDR *, u_int);
static long *xdrmem_inline (XDR *, int);
static void xdrmem_destroy (XDR *);

static const struct xdr_ops xdrmem_ops =
{
  xdrmem_getlong,
  xdrmem_putlong,
  xdrmem_getbytes,
  xdrmem_putbytes,
  xdrmem_getpos,
  xdrmem_setpos,
  xdrmem_inline,
  xdrmem_destroy
};

/*
 * The procedure xdrmem_create initializes a stream descriptor for a
 * memory buffer.
 */
void
xdrmem_create (xdrs, addr, size, op)
     XDR *xdrs;
     const caddr_t addr;
     u_int size;
     enum xdr_op op;
{

  xdrs->x_op = op;
  xdrs->x_ops = &xdrmem_ops;
  xdrs->x_private = xdrs->x_base = addr;
  xdrs->x_handy = size;
}

/*
 * Nothing needs to be done for the memory case.  The argument is clearly
 * const.
 */

static void
xdrmem_destroy (XDR *xdrs)
{
}

/*
 * Gets the next word from the memory referenced by xdrs and places it
 * in the long pointed to by lp.  It then increments the private word to
 * point at the next element.  Neither object pointed to is const
 */
static bool_t
xdrmem_getlong (xdrs, lp)
     XDR *xdrs;
     long *lp;
{

  if ((xdrs->x_handy -= 4) < 0)
    return FALSE;
  *lp = (int32_t) ntohl ((*((int32_t *) (xdrs->x_private))));
  xdrs->x_private += 4;
  return TRUE;
}

/*
 * Puts the long pointed to by lp in the memory referenced by xdrs.  It
 * then increments the private word to point at the next element.  The
 * long pointed at is const
 */
static bool_t
xdrmem_putlong (xdrs, lp)
     XDR *xdrs;
     const long *lp;
{

  if ((xdrs->x_handy -= 4) < 0)
    return FALSE;
  *(int32_t *) xdrs->x_private = htonl (*lp);
  xdrs->x_private += 4;
  return TRUE;
}

/*
 * Gets an unaligned number of bytes from the xdrs structure and writes them
 * to the address passed in addr.  Be very careful when calling this routine
 * as it could leave the xdrs pointing to an unaligned structure which is not
 * a good idea.  None of the things pointed to are const.
 */
static bool_t
xdrmem_getbytes (xdrs, addr, len)
     XDR *xdrs;
     caddr_t addr;
     u_int len;
{

  if ((xdrs->x_handy -= len) < 0)
    return FALSE;
  bcopy (xdrs->x_private, addr, len);
  xdrs->x_private += len;
  return TRUE;
}

/*
 * The complementary function to the above.  The same warnings apply about
 * unaligned data.  The source address is const.
 */
static bool_t
xdrmem_putbytes (xdrs, addr, len)
     XDR *xdrs;
     const char *addr;
     u_int len;
{

  if ((xdrs->x_handy -= len) < 0)
    return FALSE;
  bcopy (addr, xdrs->x_private, len);
  xdrs->x_private += len;
  return TRUE;
}

/*
 * Not sure what this one does.  But it clearly doesn't modify the contents
 * of xdrs.  **FIXME** does this not assume u_int == u_long?
 */
static u_int
xdrmem_getpos (xdrs)
     const XDR *xdrs;
{

  return (u_long) xdrs->x_private - (u_long) xdrs->x_base;
}

/*
 * xdrs modified
 */
static bool_t
xdrmem_setpos (xdrs, pos)
     XDR *xdrs;
     u_int pos;
{
  caddr_t newaddr = xdrs->x_base + pos;
  caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;

  if ((long) newaddr > (long) lastaddr)
    return FALSE;
  xdrs->x_private = newaddr;
  xdrs->x_handy = (long) lastaddr - (long) newaddr;
  return TRUE;
}

/*
 * xdrs modified
 */
static long *
xdrmem_inline (xdrs, len)
     XDR *xdrs;
     int len;
{
  long *buf = 0;

  if (xdrs->x_handy >= len)
    {
      xdrs->x_handy -= len;
      buf = (long *) xdrs->x_private;
      xdrs->x_private += len;
    }
  return buf;
}