/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * All rights reserved.
 *
 * 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.
 */
/*
 * xdr_sizeof.c
 *
 * General purpose routine to see how much space something will use
 * when serialized using XDR.
 */

#include <gssrpc/types.h>
#include <gssrpc/xdr.h>
#include <sys/types.h>

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

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

        return (TRUE);
}

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

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

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

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_private = NULL;
        if (xdrs->x_base) {
                free(xdrs->x_base);
                xdrs->x_base = NULL;
        }
        return;
}

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);

        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;

        /* the other harmless ones */
        ops.x_getlong =  (dummyfunc1) harmless;
        ops.x_getbytes = (dummyfunc2) 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);
        if (x.x_base)
                free(x.x_base);
        return (stat == TRUE ? (unsigned) x.x_handy: 0);
}