/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
/*        All Rights Reserved   */

/*
 * Portions of this source code were derived from Berkeley 4.3 BSD
 * under license from the Regents of the University of California.
 */

/*
 * xdr_mem.c, XDR implementation using memory buffers.
 *
 * 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 <sys/param.h>
#include <sys/types.h>
#include <sys/systm.h>

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

static struct xdr_ops *xdrmem_ops(void);

/*
 * The procedure xdrmem_create initializes a stream descriptor for a
 * memory buffer.
 */
void
xdrmem_create(XDR *xdrs, caddr_t addr, uint_t 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;
        xdrs->x_public = NULL;
}

/* ARGSUSED */
static void
xdrmem_destroy(XDR *xdrs)
{
}

static bool_t
xdrmem_getint32(XDR *xdrs, int32_t *int32p)
{
        if ((xdrs->x_handy -= (int)sizeof (int32_t)) < 0)
                return (FALSE);
        /* LINTED pointer alignment */
        *int32p = (int32_t)ntohl((uint32_t)(*((int32_t *)(xdrs->x_private))));
        xdrs->x_private += sizeof (int32_t);
        return (TRUE);
}

static bool_t
xdrmem_putint32(XDR *xdrs, int32_t *int32p)
{
        if ((xdrs->x_handy -= (int)sizeof (int32_t)) < 0)
                return (FALSE);
        /* LINTED pointer alignment */
        *(int32_t *)xdrs->x_private = (int32_t)htonl((uint32_t)(*int32p));
        xdrs->x_private += sizeof (int32_t);
        return (TRUE);
}

static bool_t
xdrmem_getbytes(XDR *xdrs, caddr_t addr, int len)
{
        if ((xdrs->x_handy -= len) < 0)
                return (FALSE);
        bcopy(xdrs->x_private, addr, len);
        xdrs->x_private += len;
        return (TRUE);
}

static bool_t
xdrmem_putbytes(XDR *xdrs, caddr_t addr, int len)
{
        if ((xdrs->x_handy -= len) < 0)
                return (FALSE);
        bcopy(addr, xdrs->x_private, len);
        xdrs->x_private += len;
        return (TRUE);
}

static uint_t
xdrmem_getpos(XDR *xdrs)
{
        return ((uint_t)((uintptr_t)xdrs->x_private - (uintptr_t)xdrs->x_base));
}

static bool_t
xdrmem_setpos(XDR *xdrs, uint_t pos)
{
        caddr_t newaddr = xdrs->x_base + pos;
        caddr_t lastaddr = xdrs->x_private + xdrs->x_handy;
        ptrdiff_t diff;

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

static rpc_inline_t *
xdrmem_inline(XDR *xdrs, int len)
{
        rpc_inline_t *buf = NULL;

        if (xdrs->x_handy >= len) {
                xdrs->x_handy -= len;
                /* LINTED pointer alignment */
                buf = (rpc_inline_t *)xdrs->x_private;
                xdrs->x_private += len;
        }
        return (buf);
}

static bool_t
xdrmem_control(XDR *xdrs, int request, void *info)
{
        xdr_bytesrec *xptr;
        int32_t *int32p;
        int len;

        switch (request) {

        case XDR_GET_BYTES_AVAIL:
                xptr = (xdr_bytesrec *)info;
                xptr->xc_is_last_record = TRUE;
                xptr->xc_num_avail = xdrs->x_handy;
                return (TRUE);

        case XDR_PEEK:
                /*
                 * Return the next 4 byte unit in the XDR stream.
                 */
                if (xdrs->x_handy < sizeof (int32_t))
                        return (FALSE);
                int32p = (int32_t *)info;
                *int32p = (int32_t)ntohl((uint32_t)
                    (*((int32_t *)(xdrs->x_private))));
                return (TRUE);

        case XDR_SKIPBYTES:
                /*
                 * Skip the next N bytes in the XDR stream.
                 */
                int32p = (int32_t *)info;
                len = RNDUP((int)(*int32p));
                if ((xdrs->x_handy -= len) < 0)
                        return (FALSE);
                xdrs->x_private += len;
                return (TRUE);

        }
        return (FALSE);
}

static struct xdr_ops *
xdrmem_ops(void)
{
        static struct xdr_ops ops;

        if (ops.x_getint32 == NULL) {
                ops.x_getbytes = xdrmem_getbytes;
                ops.x_putbytes = xdrmem_putbytes;
                ops.x_getpostn = xdrmem_getpos;
                ops.x_setpostn = xdrmem_setpos;
                ops.x_inline = xdrmem_inline;
                ops.x_destroy = xdrmem_destroy;
                ops.x_control = xdrmem_control;
                ops.x_getint32 = xdrmem_getint32;
                ops.x_putint32 = xdrmem_putint32;
        }
        return (&ops);
}