added files from rdesktop

1 files changed, 380 insertions, 0 deletions

diff --git a/uirdesktop/mppc.c b/uirdesktop/mppc.c
new file mode 100644
index 00000000..cc126c15
--- /dev/null
+++ b/uirdesktop/mppc.c
@@ -0,0 +1,380 @@
+/* -*- c-basic-offset: 8 -*-
+   rdesktop: A Remote Desktop Protocol client.
+   Protocol services - RDP decompression
+   Copyright (C) Matthew Chapman 1999-2005
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <stdio.h>
+#include <string.h>
+
+#include "rdesktop.h"
+
+/* mppc decompression                       */
+/* http://www.faqs.org/rfcs/rfc2118.html    */
+
+/* Contacts:                                */
+
+/* hifn contact mentioned in the faq is     */
+/* Robert Friend rfriend at hifn dot com    */
+
+/* if you have questions regarding MPPC     */
+/* our contact is                           */
+/* Guus Dhaeze  GDhaeze at hifn dot com     */
+
+/* Licensing:                               */
+
+/* decompression is alright as long as we   */
+/* don't compress data                      */
+
+/* Algorithm: */
+
+/* as the rfc states the algorithm seems to */
+/* be LZ77 with a sliding buffer            */
+/* that is empty at init.                   */
+
+/* the algorithm is called LZS and is       */
+/* patented for another couple of years.    */
+
+/* more information is available in         */
+/* http://www.ietf.org/ietf/IPR/hifn-ipr-draft-friend-tls-lzs-compression.txt */
+
+
+RDPCOMP g_mppc_dict;
+
+int
+mppc_expand(uint8 * data, uint32 clen, uint8 ctype, uint32 * roff, uint32 * rlen)
+{
+	int k, walker_len = 0, walker;
+	uint32 i = 0;
+	int next_offset, match_off;
+	int match_len;
+	int old_offset, match_bits;
+	BOOL big = ctype & RDP_MPPC_BIG ? True : False;
+
+	uint8 *dict = g_mppc_dict.hist;
+
+	if ((ctype & RDP_MPPC_COMPRESSED) == 0)
+	{
+		*roff = 0;
+		*rlen = clen;
+		return 0;
+	}
+
+	if ((ctype & RDP_MPPC_RESET) != 0)
+	{
+		g_mppc_dict.roff = 0;
+	}
+
+	if ((ctype & RDP_MPPC_FLUSH) != 0)
+	{
+		memset(dict, 0, RDP_MPPC_DICT_SIZE);
+		g_mppc_dict.roff = 0;
+	}
+
+	*roff = 0;
+	*rlen = 0;
+
+	walker = g_mppc_dict.roff;
+
+	next_offset = walker;
+	old_offset = next_offset;
+	*roff = old_offset;
+	if (clen == 0)
+		return 0;
+	clen += i;
+
+	do
+	{
+		if (walker_len == 0)
+		{
+			if (i >= clen)
+				break;
+			walker = data[i++] << 24;
+			walker_len = 8;
+		}
+		if (walker >= 0)
+		{
+			if (walker_len < 8)
+			{
+				if (i >= clen)
+				{
+					if (walker != 0)
+						return -1;
+					break;
+				}
+				walker |= (data[i++] & 0xff) << (24 - walker_len);
+				walker_len += 8;
+			}
+			if (next_offset >= RDP_MPPC_DICT_SIZE)
+				return -1;
+			dict[next_offset++] = (((uint32) walker) >> ((uint32) 24));
+			walker <<= 8;
+			walker_len -= 8;
+			continue;
+		}
+		walker <<= 1;
+		/* fetch next 8-bits */
+		if (--walker_len == 0)
+		{
+			if (i >= clen)
+				return -1;
+			walker = data[i++] << 24;
+			walker_len = 8;
+		}
+		/* literal decoding */
+		if (walker >= 0)
+		{
+			if (walker_len < 8)
+			{
+				if (i >= clen)
+					return -1;
+				walker |= (data[i++] & 0xff) << (24 - walker_len);
+				walker_len += 8;
+			}
+			if (next_offset >= RDP_MPPC_DICT_SIZE)
+				return -1;
+			dict[next_offset++] = (uint8) (walker >> 24 | 0x80);
+			walker <<= 8;
+			walker_len -= 8;
+			continue;
+		}
+
+		/* decode offset  */
+		/* length pair    */
+		walker <<= 1;
+		if (--walker_len < (big ? 3 : 2))
+		{
+			if (i >= clen)
+				return -1;
+			walker |= (data[i++] & 0xff) << (24 - walker_len);
+			walker_len += 8;
+		}
+
+		if (big)
+		{
+			/* offset decoding where offset len is:
+			   -63: 11111 followed by the lower 6 bits of the value
+			   64-319: 11110 followed by the lower 8 bits of the value ( value - 64 )
+			   320-2367: 1110 followed by lower 11 bits of the value ( value - 320 )
+			   2368-65535: 110 followed by lower 16 bits of the value ( value - 2368 )
+			 */
+			switch (((uint32) walker) >> ((uint32) 29))
+			{
+				case 7:	/* - 63 */
+					for (; walker_len < 9; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+					walker <<= 3;
+					match_off = ((uint32) walker) >> ((uint32) 26);
+					walker <<= 6;
+					walker_len -= 9;
+					break;
+
+				case 6:	/* 64 - 319 */
+					for (; walker_len < 11; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+
+					walker <<= 3;
+					match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
+					walker <<= 8;
+					walker_len -= 11;
+					break;
+
+				case 5:
+				case 4:	/* 320 - 2367 */
+					for (; walker_len < 13; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+
+					walker <<= 2;
+					match_off = (((uint32) walker) >> ((uint32) 21)) + 320;
+					walker <<= 11;
+					walker_len -= 13;
+					break;
+
+				default:	/* 2368 - 65535 */
+					for (; walker_len < 17; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+
+					walker <<= 1;
+					match_off = (((uint32) walker) >> ((uint32) 16)) + 2368;
+					walker <<= 16;
+					walker_len -= 17;
+					break;
+			}
+		}
+		else
+		{
+			/* offset decoding where offset len is:
+			   -63: 1111 followed by the lower 6 bits of the value
+			   64-319: 1110 followed by the lower 8 bits of the value ( value - 64 )
+			   320-8191: 110 followed by the lower 13 bits of the value ( value - 320 )
+			 */
+			switch (((uint32) walker) >> ((uint32) 30))
+			{
+				case 3:	/* - 63 */
+					if (walker_len < 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+						walker_len += 8;
+					}
+					walker <<= 2;
+					match_off = ((uint32) walker) >> ((uint32) 26);
+					walker <<= 6;
+					walker_len -= 8;
+					break;
+
+				case 2:	/* 64 - 319 */
+					for (; walker_len < 10; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+
+					walker <<= 2;
+					match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
+					walker <<= 8;
+					walker_len -= 10;
+					break;
+
+				default:	/* 320 - 8191 */
+					for (; walker_len < 14; walker_len += 8)
+					{
+						if (i >= clen)
+							return -1;
+						walker |= (data[i++] & 0xff) << (24 - walker_len);
+					}
+
+					match_off = (walker >> 18) + 320;
+					walker <<= 14;
+					walker_len -= 14;
+					break;
+			}
+		}
+		if (walker_len == 0)
+		{
+			if (i >= clen)
+				return -1;
+			walker = data[i++] << 24;
+			walker_len = 8;
+		}
+
+		/* decode length of match */
+		match_len = 0;
+		if (walker >= 0)
+		{		/* special case - length of 3 is in bit 0 */
+			match_len = 3;
+			walker <<= 1;
+			walker_len--;
+		}
+		else
+		{
+			/* this is how it works len of:
+			   4-7: 10 followed by 2 bits of the value
+			   8-15: 110 followed by 3 bits of the value
+			   16-31: 1110 followed by 4 bits of the value
+			   32-63: .... and so forth
+			   64-127:
+			   128-255:
+			   256-511:
+			   512-1023:
+			   1024-2047:
+			   2048-4095:
+			   4096-8191:
+
+			   i.e. 4097 is encoded as: 111111111110 000000000001
+			   meaning 4096 + 1...
+			 */
+			match_bits = big ? 14 : 11;	/* 11 or 14 bits of value at most */
+			do
+			{
+				walker <<= 1;
+				if (--walker_len == 0)
+				{
+					if (i >= clen)
+						return -1;
+					walker = data[i++] << 24;
+					walker_len = 8;
+				}
+				if (walker >= 0)
+					break;
+				if (--match_bits == 0)
+				{
+					return -1;
+				}
+			}
+			while (1);
+			match_len = (big ? 16 : 13) - match_bits;
+			walker <<= 1;
+			if (--walker_len < match_len)
+			{
+				for (; walker_len < match_len; walker_len += 8)
+				{
+					if (i >= clen)
+					{
+						return -1;
+					}
+					walker |= (data[i++] & 0xff) << (24 - walker_len);
+				}
+			}
+
+			match_bits = match_len;
+			match_len =
+				((walker >> (32 - match_bits)) & (~(-1 << match_bits))) | (1 <<
+											   match_bits);
+			walker <<= match_bits;
+			walker_len -= match_bits;
+		}
+		if (next_offset + match_len >= RDP_MPPC_DICT_SIZE)
+		{
+			return -1;
+		}
+		/* memory areas can overlap - meaning we can't use memXXX functions */
+		k = (next_offset - match_off) & (big ? 65535 : 8191);
+		do
+		{
+			dict[next_offset++] = dict[k++];
+		}
+		while (--match_len != 0);
+	}
+	while (1);
+
+	/* store history offset */
+	g_mppc_dict.roff = next_offset;
+
+	*roff = old_offset;
+	*rlen = next_offset - old_offset;
+
+	return 0;
+}