a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* -*- c-basic-offset: 8 -*-
a180a41bba1d50822df23fff0099e90b86638b89vboxsync rdesktop: A Remote Desktop Protocol client.
a180a41bba1d50822df23fff0099e90b86638b89vboxsync Protocol services - RDP decompression
a180a41bba1d50822df23fff0099e90b86638b89vboxsync Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync This program is free software: you can redistribute it and/or modify
a180a41bba1d50822df23fff0099e90b86638b89vboxsync it under the terms of the GNU General Public License as published by
a180a41bba1d50822df23fff0099e90b86638b89vboxsync the Free Software Foundation, either version 3 of the License, or
a180a41bba1d50822df23fff0099e90b86638b89vboxsync (at your option) any later version.
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync This program is distributed in the hope that it will be useful,
a180a41bba1d50822df23fff0099e90b86638b89vboxsync but WITHOUT ANY WARRANTY; without even the implied warranty of
a180a41bba1d50822df23fff0099e90b86638b89vboxsync MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
a180a41bba1d50822df23fff0099e90b86638b89vboxsync GNU General Public License for more details.
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync You should have received a copy of the GNU General Public License
a180a41bba1d50822df23fff0099e90b86638b89vboxsync along with this program. If not, see <http://www.gnu.org/licenses/>.
a180a41bba1d50822df23fff0099e90b86638b89vboxsync*/
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync/*
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * Oracle GPL Disclaimer: For the avoidance of doubt, except that if any license choice
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * other than GPL or LGPL is available it will apply instead, Oracle elects to use only
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * the General Public License version 2 (GPLv2) at this time for any software where
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * a choice of GPL license versions is made available with the language indicating
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * that GPLv2 or any later version may be used, or where a choice of which version
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync * of the GPL is applied is otherwise unspecified.
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync */
6e9aa255e3376b2da5824c09c4c62bc233463bfevboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync#include <stdio.h>
a180a41bba1d50822df23fff0099e90b86638b89vboxsync#include <string.h>
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync#include "rdesktop.h"
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* mppc decompression */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* http://www.faqs.org/rfcs/rfc2118.html */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* Contacts: */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* hifn contact mentioned in the faq is */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* Robert Friend rfriend at hifn dot com */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* if you have questions regarding MPPC */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* our contact is */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* Guus Dhaeze GDhaeze at hifn dot com */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* Licensing: */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* decompression is alright as long as we */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* don't compress data */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* Algorithm: */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* as the rfc states the algorithm seems to */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* be LZ77 with a sliding buffer */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* that is empty at init. */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* the algorithm is called LZS and is */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* patented for another couple of years. */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* more information is available in */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync/* http://www.ietf.org/ietf/IPR/hifn-ipr-draft-friend-tls-lzs-compression.txt */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsyncRDPCOMP g_mppc_dict;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsyncint
a180a41bba1d50822df23fff0099e90b86638b89vboxsyncmppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync{
a180a41bba1d50822df23fff0099e90b86638b89vboxsync int k, walker_len = 0, walker;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync uint32 i = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync int next_offset, match_off;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync int match_len;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync int old_offset, match_bits;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync RD_BOOL big = ctype & RDP_MPPC_BIG ? True : False;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync uint8 *dict = g_mppc_dict.hist;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if ((ctype & RDP_MPPC_COMPRESSED) == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *roff = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *rlen = clen;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if ((ctype & RDP_MPPC_RESET) != 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync g_mppc_dict.roff = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if ((ctype & RDP_MPPC_FLUSH) != 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync memset(dict, 0, RDP_MPPC_DICT_SIZE);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync g_mppc_dict.roff = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *roff = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *rlen = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker = g_mppc_dict.roff;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync next_offset = walker;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync old_offset = next_offset;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *roff = old_offset;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (clen == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync clen += i;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync do
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker_len == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker = data[i++] << 24;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len = 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker >= 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker_len < 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker != 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len += 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (next_offset >= RDP_MPPC_DICT_SIZE)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync dict[next_offset++] = (((uint32) walker) >> ((uint32) 24));
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync continue;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* fetch next 8-bits */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (--walker_len == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker = data[i++] << 24;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len = 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* literal decoding */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker >= 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker_len < 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len += 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (next_offset >= RDP_MPPC_DICT_SIZE)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync dict[next_offset++] = (uint8) (walker >> 24 | 0x80);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync continue;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* decode offset */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* length pair */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (--walker_len < (big ? 3 : 2))
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len += 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (big)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* offset decoding where offset len is:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync -63: 11111 followed by the lower 6 bits of the value
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 64-319: 11110 followed by the lower 8 bits of the value ( value - 64 )
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 320-2367: 1110 followed by lower 11 bits of the value ( value - 320 )
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 2368-65535: 110 followed by lower 16 bits of the value ( value - 2368 )
a180a41bba1d50822df23fff0099e90b86638b89vboxsync */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync switch (((uint32) walker) >> ((uint32) 29))
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 7: /* - 63 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 9; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 3;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = ((uint32) walker) >> ((uint32) 26);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 6;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 9;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 6: /* 64 - 319 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 11; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 3;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 11;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 5:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 4: /* 320 - 2367 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 13; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 2;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = (((uint32) walker) >> ((uint32) 21)) + 320;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 11;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 13;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync default: /* 2368 - 65535 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 17; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = (((uint32) walker) >> ((uint32) 16)) + 2368;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 16;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 17;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync else
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* offset decoding where offset len is:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync -63: 1111 followed by the lower 6 bits of the value
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 64-319: 1110 followed by the lower 8 bits of the value ( value - 64 )
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 320-8191: 110 followed by the lower 13 bits of the value ( value - 320 )
a180a41bba1d50822df23fff0099e90b86638b89vboxsync */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync switch (((uint32) walker) >> ((uint32) 30))
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 3: /* - 63 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker_len < 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len += 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 2;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = ((uint32) walker) >> ((uint32) 26);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 6;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync case 2: /* 64 - 319 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 10; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 2;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 10;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync default: /* 320 - 8191 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < 14; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_off = (walker >> 18) + 320;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 14;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= 14;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker_len == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker = data[i++] << 24;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len = 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* decode length of match */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_len = 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker >= 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync { /* special case - length of 3 is in bit 0 */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_len = 3;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len--;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync else
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* this is how it works len of:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 4-7: 10 followed by 2 bits of the value
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 8-15: 110 followed by 3 bits of the value
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 16-31: 1110 followed by 4 bits of the value
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 32-63: .... and so forth
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 64-127:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 128-255:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 256-511:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 512-1023:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 1024-2047:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 2048-4095:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync 4096-8191:
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync i.e. 4097 is encoded as: 111111111110 000000000001
a180a41bba1d50822df23fff0099e90b86638b89vboxsync meaning 4096 + 1...
a180a41bba1d50822df23fff0099e90b86638b89vboxsync */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_bits = big ? 14 : 11; /* 11 or 14 bits of value at most */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync do
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (--walker_len == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker = data[i++] << 24;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len = 8;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (walker >= 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync break;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (--match_bits == 0)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync while (1);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_len = (big ? 16 : 13) - match_bits;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= 1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (--walker_len < match_len)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync for (; walker_len < match_len; walker_len += 8)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (i >= clen)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker |= (data[i++] & 0xff) << (24 - walker_len);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_bits = match_len;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_len =
a180a41bba1d50822df23fff0099e90b86638b89vboxsync ((walker >> (32 - match_bits)) & (~(-1 << match_bits))) | (1 <<
a180a41bba1d50822df23fff0099e90b86638b89vboxsync match_bits);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker <<= match_bits;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync walker_len -= match_bits;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync if (next_offset + match_len >= RDP_MPPC_DICT_SIZE)
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return -1;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* memory areas can overlap - meaning we can't use memXXX functions */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync k = (next_offset - match_off) & (big ? 65535 : 8191);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync do
a180a41bba1d50822df23fff0099e90b86638b89vboxsync {
a180a41bba1d50822df23fff0099e90b86638b89vboxsync dict[next_offset++] = dict[k++];
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync while (--match_len != 0);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync }
a180a41bba1d50822df23fff0099e90b86638b89vboxsync while (1);
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync /* store history offset */
a180a41bba1d50822df23fff0099e90b86638b89vboxsync g_mppc_dict.roff = next_offset;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *roff = old_offset;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync *rlen = next_offset - old_offset;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync
a180a41bba1d50822df23fff0099e90b86638b89vboxsync return 0;
a180a41bba1d50822df23fff0099e90b86638b89vboxsync}