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FreeRDP/libfreerdp/codec/mppc_dec.c

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/**
* FreeRDP: A Remote Desktop Protocol Implementation
* Implements Microsoft Point to Point Compression (MPPC) protocol
*
* Copyright 2011 Laxmikant Rashinkar <LK.Rashinkar@gmail.com>
* Copyright 2012 Jiten Pathy
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winpr/crt.h>
#include <freerdp/codec/mppc_dec.h>
static BYTE HuffLenLEC[] = {
0x6, 0x6, 0x6, 0x7, 0x7, 0x7, 0x7, 0x7, 0x7, 0x7, 0x7, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x9, 0x8, 0x9, 0x9, 0x9, 0x9, 0x8, 0x8, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x8, 0x9, 0x9, 0xa, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0xa, 0x9, 0xa, 0xa, 0xa, 0x9, 0x9, 0xa, 0x9, 0xa, 0x9, 0xa, 0x9, 0x9, 0x9, 0xa, 0xa, 0x9, 0xa, 0x9, 0x9, 0x8, 0x9, 0x9, 0x9, 0x9, 0xa, 0xa, 0xa, 0x9, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x8, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0x7, 0x9, 0x9, 0xa, 0x9, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xd, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xb, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0xa, 0x9, 0xa, 0x8, 0x9, 0x9, 0xa, 0x9, 0xa, 0xa, 0xa, 0x9, 0xa, 0xa, 0xa, 0x9, 0x9, 0x8, 0x7, 0xd, 0xd, 0x7, 0x7, 0xa, 0x7, 0x7, 0x6, 0x6, 0x6, 0x6, 0x5, 0x6, 0x6, 0x6, 0x5, 0x6, 0x5, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x8, 0x5, 0x6, 0x7, 0x7 };
static UINT16 HuffIndexLEC[512] = {
0x007b, 0xff1f, 0xff0d, 0xfe27, 0xfe00, 0xff05, 0xff17, 0xfe68, 0x00c5, 0xfe07, 0xff13, 0xfec0, 0xff08, 0xfe18, 0xff1b, 0xfeb3, 0xfe03, 0x00a2, 0xfe42, 0xff10, 0xfe0b, 0xfe02, 0xfe91, 0xff19, 0xfe80, 0x00e9, 0xfe3a, 0xff15, 0xfe12, 0x0057, 0xfed7, 0xff1d, 0xff0e, 0xfe35, 0xfe69, 0xff22, 0xff18, 0xfe7a, 0xfe01, 0xff23, 0xff14, 0xfef4, 0xfeb4, 0xfe09, 0xff1c, 0xfec4, 0xff09, 0xfe60, 0xfe70, 0xff12, 0xfe05, 0xfe92, 0xfea1, 0xff1a, 0xfe0f, 0xff07, 0xfe56, 0xff16, 0xff02, 0xfed8, 0xfee8, 0xff1e, 0xfe1d, 0x003b, 0xffff, 0xff06, 0xffff, 0xfe71, 0xfe89, 0xffff, 0xffff, 0xfe2c, 0xfe2b, 0xfe20, 0xffff, 0xfebb, 0xfecf, 0xfe08, 0xffff, 0xfee0, 0xfe0d, 0xffff, 0xfe99, 0xffff, 0xfe04, 0xfeaa, 0xfe49, 0xffff, 0xfe17, 0xfe61, 0xfedf, 0xffff, 0xfeff, 0xfef6, 0xfe4c, 0xffff, 0xffff, 0xfe87, 0xffff, 0xff24, 0xffff, 0xfe3c, 0xfe72, 0xffff, 0xffff, 0xfece, 0xffff, 0xfefe, 0xffff, 0xfe23, 0xfebc, 0xfe0a, 0xfea9, 0xffff, 0xfe11, 0xffff, 0xfe82, 0xffff, 0xfe06, 0xfe9a, 0xfef5, 0xffff, 0xfe22, 0xfe4d, 0xfe5f, 0xffff, 0xff03, 0xfee1, 0xffff, 0xfeca, 0xfecc, 0xffff, 0xfe19, 0xffff, 0xfeb7, 0xffff, 0xffff, 0xfe83, 0xfe29, 0xffff, 0xffff, 0xffff, 0xfe6c, 0xffff, 0xfeed, 0xffff, 0xffff, 0xfe46, 0xfe5c, 0xfe15, 0xffff, 0xfedb, 0xfea6, 0xffff, 0xffff, 0xfe44, 0xffff, 0xfe0c, 0xffff, 0xfe95, 0xfefc, 0xffff, 0xffff, 0xfeb8, 0x16c9, 0xffff, 0xfef0, 0xffff, 0xfe38, 0xffff, 0xffff, 0xfe6d, 0xfe7e, 0xffff, 0xffff, 0xffff, 0xffff, 0xfe5b, 0xfedc, 0xffff, 0xffff, 0xfeec, 0xfe47, 0xfe1f, 0xffff, 0xfe7f, 0xfe96, 0xffff, 0xffff, 0xfea5, 0xffff, 0xfe10, 0xfe40, 0xfe32, 0xfebf, 0xffff, 0xffff, 0xfed4, 0xfef1, 0xffff, 0xffff, 0xffff, 0xfe75, 0xffff, 0xffff, 0xfe8d, 0xfe31, 0xffff, 0xfe65, 0xfe1b, 0xffff, 0xfee4, 0xfefb, 0xffff, 0xffff, 0xfe52, 0xffff, 0xfe0e, 0xffff, 0xfe9d, 0xfeaf, 0xffff, 0xffff, 0xfe51, 0xfed3, 0xffff, 0xff20, 0xffff, 0xfe2f, 0xffff, 0xffff, 0xfec1, 0xfe8c, 0xffff, 0xffff, 0xffff, 0xfe3f, 0xffff, 0xffff, 0xfe76, 0xffff, 0xfefa, 0xfe53, 0xfe25, 0xffff, 0xfe64, 0xfee5, 0xffff, 0xffff, 0xfeae, 0xffff, 0xfe13, 0xffff, 0xfe88, 0xfe9e, 0xffff, 0xfe43, 0xffff, 0xffff, 0xfea4, 0xfe93, 0xffff, 0xffff, 0xffff, 0xfe3d, 0xffff, 0xffff, 0xfeeb, 0xfed9, 0xffff, 0xfe14, 0xfe5a, 0xffff, 0xfe28, 0xfe7d, 0xffff, 0xffff, 0xfe6a, 0xffff, 0xffff, 0xff01, 0xfec6, 0xfec8, 0xffff, 0xffff, 0xfeb5, 0xffff, 0xffff, 0xffff, 0xfe94, 0xfe78, 0xffff, 0xffff, 0xffff, 0xfea3, 0xffff, 0xffff, 0xfeda, 0xfe58, 0xffff, 0xfe1e, 0xfe45, 0xfeea, 0xffff, 0xfe6b, 0xffff, 0xffff, 0xfe37, 0xffff, 0xffff, 0xffff, 0xfe7c, 0xfeb6, 0xffff, 0xffff, 0xfef8, 0xffff, 0xffff, 0xffff, 0xfec7, 0xfe9b, 0xffff, 0xffff, 0xffff, 0xfe50, 0xffff, 0xffff, 0xfead, 0xfee2, 0xffff, 0xfe1a, 0xfe63, 0xfe4e, 0xffff, 0xffff, 0xfef9, 0xffff, 0xfe73, 0xffff, 0xffff, 0xffff, 0xfe30, 0xfe8b, 0xffff, 0xffff, 0xfebd, 0xfe2e, 0x0100, 0xffff, 0xfeee, 0xfed2, 0xffff, 0xffff, 0xffff, 0xfeac, 0xffff, 0xffff, 0xfe9c, 0xfe84, 0xffff, 0xfe24, 0xfe4f, 0xfef7, 0xffff, 0xffff, 0xfee3, 0xfe62, 0xffff, 0xffff, 0xffff, 0xffff, 0xfe8a, 0xfe74, 0xffff, 0xffff, 0xfe3e, 0xffff, 0xffff, 0xffff, 0xfed1, 0xfebe, 0xffff, 0xffff, 0xfe2d, 0xffff, 0xfe4a, 0xfef3, 0xffff, 0xffff, 0xfedd, 0xfe5e, 0xfe16, 0xffff, 0xfe48, 0xfea8, 0xffff, 0xfeab, 0xfe97, 0xffff, 0xffff, 0xfed0, 0xffff, 0xffff, 0xfecd, 0xfeb9, 0xffff, 0xffff, 0xffff, 0xfe2a, 0xffff, 0xffff, 0xfe86, 0xfe6e, 0xffff, 0xffff, 0xffff, 0xfede, 0xffff, 0xffff, 0xfe5d, 0xfe4b, 0xfe21, 0xffff, 0xfeef, 0xfe98, 0xffff, 0xffff, 0xfe81, 0xffff, 0xffff, 0xffff, 0xfea7, 0xffff, 0xfeba, 0xfefd, 0xffff, 0xffff, 0xffff, 0xfecb, 0xffff, 0xffff, 0xfe6f, 0xfe39, 0xffff, 0xffff, 0xffff, 0xfe85, 0xffff, 0x010c, 0xfee6, 0xfe67, 0xfe1c, 0xffff, 0xfe54, 0xfeb2, 0xffff, 0xffff, 0xfe9f, 0xffff, 0xffff, 0xffff, 0xfe59, 0xfeb1, 0xffff, 0xfec2, 0xffff, 0xffff, 0xfe36, 0xfef2, 0xffff, 0xffff, 0xfed6, 0xfe77, 0xffff, 0xffff, 0xffff, 0xfe33, 0xffff, 0xffff, 0xfe8f, 0xfe55, 0xfe26, 0x010a, 0xff04, 0xfee7, 0xffff, 0x0121, 0xfe66, 0xffff, 0xffff, 0xffff, 0xfeb0, 0xfea0, 0xffff, 0x010f, 0xfe90, 0xffff, 0xffff, 0xfed5, 0xffff, 0xffff, 0xfec3, 0xfe34, 0xffff, 0xffff, 0xffff, 0xfe8e, 0xffff, 0x0111, 0xfe79, 0xfe41, 0x010b };
static UINT16 LECHTab[] = {511, 0, 508, 448, 494, 347, 486, 482};
static BYTE HuffLenLOM[] = {
0x4, 0x2, 0x3, 0x4, 0x3, 0x4, 0x4, 0x5, 0x4, 0x5, 0x5, 0x6, 0x6, 0x7, 0x7, 0x8, 0x7, 0x8, 0x8, 0x9, 0x9, 0x8, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9, 0x9 };
static UINT16 HuffIndexLOM[] = {
0xfe1, 0xfe0, 0xfe2, 0xfe8, 0xe, 0xfe5, 0xfe4, 0xfea, 0xff1, 0xfe3, 0x15, 0xfe7, 0xfef, 0x46, 0xff0, 0xfed, 0xfff, 0xff7, 0xffb, 0x19, 0xffd, 0xff4, 0x12c, 0xfeb, 0xffe, 0xff6, 0xffa, 0x89, 0xffc, 0xff3, 0xff8, 0xff2 };
static BYTE LOMHTab[] = {0, 4, 10, 19};
static BYTE CopyOffsetBitsLUT[] = {
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15 };
static UINT32 CopyOffsetBaseLUT[] = {
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577, 32769, 49153, 65537 };
static BYTE LOMBitsLUT[] = {
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 6, 6, 8, 8, 14, 14 };
static UINT16 LOMBaseLUT[] = {
2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 22, 26, 30, 34, 42, 50, 58, 66, 82, 98, 114, 130, 194, 258, 514, 2, 2 };
UINT16 LEChash(UINT16 key)
{
return ((key & 0x1ff) ^ (key >> 9) ^ (key >> 4) ^ (key >> 7));
}
UINT16 LOMhash(UINT16 key)
{
return ((key & 0x1f) ^ (key >> 5) ^ (key >> 9));
}
UINT16 miniLEChash(UINT16 key)
{
UINT16 h;
h = ((((key >> 8) ^ (key & 0xff)) >> 2) & 0xf);
if(key >> 9)
h = ~h;
return (h % 12);
}
BYTE miniLOMhash(UINT16 key)
{
BYTE h;
h = (key >> 4) & 0xf;
return ((h ^ (h >> 2) ^ (h >> 3)) & 0x3);
}
UINT16 getLECindex(UINT16 huff)
{
UINT16 h = HuffIndexLEC[LEChash(huff)];
if((h ^ huff) >> 9)
return h & 0x1ff;
else
return HuffIndexLEC[LECHTab[miniLEChash(huff)]];
}
UINT16 getLOMindex(UINT16 huff)
{
UINT16 h = HuffIndexLOM[LOMhash(huff)];
if((h ^ huff) >> 5)
{
return h & 0x1f;
}
else
return HuffIndexLOM[LOMHTab[miniLOMhash(huff)]];
}
UINT32 transposebits(UINT32 x)
{
x = ((x & 0x55555555) << 1) | ((x >> 1) & 0x55555555);
x = ((x & 0x33333333) << 2) | ((x >> 2) & 0x33333333);
x = ((x & 0x0f0f0f0f) << 4) | ((x >> 4) & 0x0f0f0f0f);
if((x >> 8) == 0)
return x;
x = ((x & 0x00ff00ff) << 8) | ((x >> 8) & 0x00ff00ff);
if((x >> 16) == 0)
return x;
x = ((x & 0x0000ffff) << 16) | ((x >> 16) & 0x0000ffff);
return x;
}
#define cache_add(_s, _x) do { \
*((UINT32*)((_s)+2)) <<= 16; \
*((UINT32*)((_s)+2)) |= (*((UINT32*)(_s)) >> 16); \
*((UINT32*)(_s)) = (*((UINT32*)(_s)) << 16) | (_x); } while(0)
#define cache_swap(_s, _i) do { \
UINT16 t = *(_s); \
*(_s) = *((_s) + (_i)); \
*((_s) + (_i)) = t; } while(0)
/**
* decompress RDP 6 data
*
* @param rdp per session information
* @param cbuf compressed data
* @param len length of compressed data
* @param ctype compression flags
* @param roff starting offset of uncompressed data
* @param rlen length of uncompressed data
*
* @return True on success, False on failure
*/
int decompress_rdp_6(struct rdp_mppc_dec* dec, BYTE* cbuf, int len, int ctype, UINT32* roff, UINT32* rlen)
{
BYTE* history_buf; /* uncompressed data goes here */
UINT16* offset_cache; /* Copy Offset cache */
BYTE* history_ptr; /* points to next free slot in bistory_buf */
UINT32 d32; /* we process 4 compressed bytes at a time */
UINT16 copy_offset; /* location to copy data from */
UINT16 lom; /* length of match */
UINT16 LUTIndex; /* LookUp table Index */
BYTE* src_ptr; /* used while copying compressed data */
BYTE* cptr; /* points to next byte in cbuf */
BYTE cur_byte; /* last byte fetched from cbuf */
int bits_left; /* bits left in d32 for processing */
int cur_bits_left; /* bits left in cur_byte for processing */
int tmp, i;
UINT32 i32;
if ((dec == NULL) || (dec->history_buf == NULL))
{
fprintf(stderr, "decompress_rdp_6: null\n");
return FALSE;
}
src_ptr = 0;
cptr = cbuf;
copy_offset = 0;
lom = 0;
bits_left = 0;
cur_bits_left = 0;
d32 = 0;
cur_byte = 0;
*rlen = 0;
/* get start of history buffer */
history_buf = dec->history_buf;
/* get start of offset_cache */
offset_cache = dec->offset_cache;
/* get next free slot in history buffer */
history_ptr = dec->history_ptr;
*roff = history_ptr - history_buf;
if (ctype & PACKET_AT_FRONT)
{
/* slid history_buf and reset history_buf to middle */
memmove(history_buf, (history_buf + (history_ptr - history_buf - 32768)), 32768);
history_ptr = history_buf + 32768;
dec->history_ptr = history_ptr;
*roff = 32768;
}
if (ctype & PACKET_FLUSHED)
{
/* re-init history buffer */
history_ptr = dec->history_buf;
memset(history_buf, 0, RDP6_HISTORY_BUF_SIZE);
memset(offset_cache, 0, RDP6_OFFSET_CACHE_SIZE);
*roff = 0;
}
if ((ctype & PACKET_COMPRESSED) != PACKET_COMPRESSED)
{
/* data in cbuf is not compressed - copy to history buf as is */
memcpy(history_ptr, cbuf, len);
history_ptr += len;
*rlen = history_ptr - dec->history_ptr;
dec->history_ptr = history_ptr;
return TRUE;
}
/* load initial data */
tmp = 0;
while (cptr < cbuf + len)
{
i32 = *cptr++;
d32 |= i32 << tmp;
bits_left += 8;
tmp += 8;
if (tmp >= 32)
{
break;
}
}
d32 = transposebits(d32);
if (cptr < cbuf + len)
{
cur_byte = transposebits(*cptr++);
cur_bits_left = 8;
}
else
{
cur_bits_left = 0;
}
/*
** start uncompressing data in cbuf
*/
while (bits_left >= 8)
{
/* Decode Huffman Code for Literal/EOS/CopyOffset */
copy_offset = 0;
for(i = 0x5; i <= 0xd; i++)
{
if(i == 0xc)
continue;
i32 = transposebits((d32 & (0xffffffff << (32 - i))));
i32 = getLECindex(i32);
if(i == HuffLenLEC[i32])
break;
}
d32 <<= i;
bits_left -= i;
if(i32 < 256)
*history_ptr++ = (BYTE)i32;
else if(i32 > 256 && i32 < 289)
{
LUTIndex = i32 - 257;
tmp = CopyOffsetBitsLUT[LUTIndex];
copy_offset = CopyOffsetBaseLUT[LUTIndex] - 0x1;
if(tmp != 0)
copy_offset += transposebits(d32 & (0xffffffff << (32 - tmp)));
cache_add(offset_cache, copy_offset);
d32 <<= tmp;
bits_left -= tmp;
}
else if( i32 > 288 && i32 < 293)
{
LUTIndex = i32 - 289;
copy_offset = *(offset_cache + LUTIndex);
if(LUTIndex != 0)
cache_swap(offset_cache, LUTIndex);
}
else if(i32 == 256)
break;
/*
** get more bits before we process length of match
*/
/* how may bits do we need to get? */
tmp = 32 - bits_left;
while (tmp)
{
if (cur_bits_left < tmp)
{
/* we have less bits than we need */
i32 = cur_byte >> (8 - cur_bits_left);
d32 |= i32 << ((32 - bits_left) - cur_bits_left);
bits_left += cur_bits_left;
tmp -= cur_bits_left;
if (cptr < cbuf + len)
{
/* more compressed data available */
cur_byte = transposebits(*cptr++);
cur_bits_left = 8;
}
else
{
/* no more compressed data available */
tmp = 0;
cur_bits_left = 0;
}
}
else if (cur_bits_left > tmp)
{
/* we have more bits than we need */
d32 |= cur_byte >> (8 - tmp);
cur_byte <<= tmp;
cur_bits_left -= tmp;
bits_left = 32;
break;
}
else
{
/* we have just the right amount of bits */
d32 |= cur_byte >> (8 - tmp);
bits_left = 32;
if (cptr < cbuf + len)
{
cur_byte = transposebits(*cptr++);
cur_bits_left = 8;
}
else
cur_bits_left = 0;
break;
}
}
if (!copy_offset)
continue;
for(i = 0x2; i <= 0x9; i++)
{
i32 = transposebits((d32 & (0xffffffff << (32 - i))));
i32 = getLOMindex(i32);
if(i == HuffLenLOM[i32])
break;
}
d32 <<= i;
bits_left -= i;
tmp = LOMBitsLUT[i32];
lom = LOMBaseLUT[i32];
if(tmp != 0)
lom += transposebits(d32 & (0xffffffff << (32 - tmp)));
d32 <<= tmp;
bits_left -= tmp;
/* now that we have copy_offset and LoM, process them */
src_ptr = history_ptr - copy_offset;
tmp = (lom > copy_offset) ? copy_offset : lom;
i32 = 0;
if (src_ptr >= dec->history_buf)
{
while(tmp > 0)
{
*history_ptr++ = *src_ptr++;
tmp--;
}
while (lom > copy_offset)
{
i32 = ((i32 >= copy_offset)) ? 0 : i32;
*history_ptr++ = *(src_ptr + i32++);
lom--;
}
}
else
{
src_ptr = dec->history_buf_end - (copy_offset - (history_ptr - dec->history_buf));
src_ptr++;
while (tmp && (src_ptr <= dec->history_buf_end))
{
*history_ptr++ = *src_ptr++;
tmp--;
}
src_ptr = dec->history_buf;
while (tmp > 0)
{
*history_ptr++ = *src_ptr++;
tmp--;
}
while (lom > copy_offset)
{
i32 = ((i32 > copy_offset)) ? 0 : i32;
*history_ptr++ = *(src_ptr + i32++);
lom--;
}
}
/*
** get more bits before we restart the loop
*/
/* how may bits do we need to get? */
assert(bits_left <= 32);
assert(cur_bits_left <= bits_left);
tmp = 32 - bits_left;
while (tmp)
{
if (cur_bits_left < tmp)
{
/* we have less bits than we need */
i32 = cur_byte >> (8 - cur_bits_left);
d32 |= (i32 << ((32 - bits_left) - cur_bits_left)) & 0xFFFFFFFF;
bits_left += cur_bits_left;
tmp -= cur_bits_left;
if (cptr < cbuf + len)
{
/* more compressed data available */
cur_byte = transposebits(*cptr++);
cur_bits_left = 8;
}
else
{
/* no more compressed data available */
tmp = 0;
cur_bits_left = 0;
}
}
else if (cur_bits_left > tmp)
{
/* we have more bits than we need */
d32 |= cur_byte >> (8 - tmp);
cur_byte <<= tmp;
cur_bits_left -= tmp;
bits_left = 32;
break;
}
else
{
/* we have just the right amount of bits */
d32 |= cur_byte >> (8 - tmp);
bits_left = 32;
if (cptr < cbuf + len)
{
cur_byte = transposebits(*cptr++);
cur_bits_left = 8;
}
else
{
cur_bits_left = 0;
}
break;
}
}
}/* end while (bits_left >= 8) */
if(ctype & PACKET_FLUSHED)
*rlen = history_ptr - history_buf;
else
*rlen = history_ptr - dec->history_ptr;
dec->history_ptr = history_ptr;
return TRUE;
}
/**
* allocate space to store history buffer
*
* @param rdp rdp struct that contains rdp_mppc struct
* @return pointer to new struct, or NULL on failure
*/
struct rdp_mppc_dec* mppc_dec_new(void)
{
struct rdp_mppc_dec* ptr;
ptr = (struct rdp_mppc_dec*) malloc(sizeof(struct rdp_mppc_dec));
if (!ptr)
{
fprintf(stderr, "mppc_new(): system out of memory\n");
return NULL;
}
ptr->history_buf = (BYTE*) malloc(RDP6_HISTORY_BUF_SIZE);
ZeroMemory(ptr->history_buf, RDP6_HISTORY_BUF_SIZE);
ptr->offset_cache = (UINT16*) malloc(RDP6_OFFSET_CACHE_SIZE);
ZeroMemory(ptr->offset_cache, RDP6_OFFSET_CACHE_SIZE);
if (!ptr->history_buf)
{
fprintf(stderr, "mppc_new(): system out of memory\n");
free(ptr);
return NULL;
}
ptr->history_ptr = ptr->history_buf;
ptr->history_buf_end = ptr->history_buf + RDP6_HISTORY_BUF_SIZE - 1;
return ptr;
}
/**
* free history buffer
*
* @param rdp rdp struct that contains rdp_mppc struct
*/
void mppc_dec_free(struct rdp_mppc_dec* dec)
{
if (!dec)
{
return;
}
if (dec->history_buf)
{
free(dec->history_buf);
dec->history_buf = NULL;
dec->history_ptr = NULL;
}
if (dec->offset_cache)
{
free(dec->offset_cache);
dec->offset_cache = NULL;
}
free(dec);
}
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