ReactOS 0.4.15-dev-7991-ge77da17
Functions | Variables
mppc.c File Reference
#include <stdio.h>
#include <string.h>
#include "precomp.h"
Include dependency graph for mppc.c:

Go to the source code of this file.

Functions

int mppc_expand (uint8 *data, uint32 clen, uint8 ctype, uint32 *roff, uint32 *rlen)
 

Variables

RDPCOMP g_mppc_dict
 

Function Documentation

◆ mppc_expand()

int mppc_expand ( uint8 *  data,
uint32  clen,
uint8  ctype,
uint32 *  roff,
uint32 *  rlen 
)

Definition at line 58 of file mppc.c.

59{
60 int k, walker_len = 0, walker;
61 uint32 i = 0;
62 int next_offset, match_off;
63 int match_len;
64 int old_offset, match_bits;
65 RD_BOOL big = ctype & RDP_MPPC_BIG ? True : False;
66
67 uint8 *dict = g_mppc_dict.hist;
68
69 if ((ctype & RDP_MPPC_COMPRESSED) == 0)
70 {
71 *roff = 0;
72 *rlen = clen;
73 return 0;
74 }
75
76 if ((ctype & RDP_MPPC_RESET) != 0)
77 {
78 g_mppc_dict.roff = 0;
79 }
80
81 if ((ctype & RDP_MPPC_FLUSH) != 0)
82 {
83 memset(dict, 0, RDP_MPPC_DICT_SIZE);
84 g_mppc_dict.roff = 0;
85 }
86
87 *roff = 0;
88 *rlen = 0;
89
90 walker = g_mppc_dict.roff;
91
92 next_offset = walker;
93 old_offset = next_offset;
94 *roff = old_offset;
95 if (clen == 0)
96 return 0;
97 clen += i;
98
99 do
100 {
101 if (walker_len == 0)
102 {
103 if (i >= clen)
104 break;
105 walker = data[i++] << 24;
106 walker_len = 8;
107 }
108 if (walker >= 0)
109 {
110 if (walker_len < 8)
111 {
112 if (i >= clen)
113 {
114 if (walker != 0)
115 return -1;
116 break;
117 }
118 walker |= (data[i++] & 0xff) << (24 - walker_len);
119 walker_len += 8;
120 }
121 if (next_offset >= RDP_MPPC_DICT_SIZE)
122 return -1;
123 dict[next_offset++] = (((uint32) walker) >> ((uint32) 24));
124 walker <<= 8;
125 walker_len -= 8;
126 continue;
127 }
128 walker <<= 1;
129 /* fetch next 8-bits */
130 if (--walker_len == 0)
131 {
132 if (i >= clen)
133 return -1;
134 walker = data[i++] << 24;
135 walker_len = 8;
136 }
137 /* literal decoding */
138 if (walker >= 0)
139 {
140 if (walker_len < 8)
141 {
142 if (i >= clen)
143 return -1;
144 walker |= (data[i++] & 0xff) << (24 - walker_len);
145 walker_len += 8;
146 }
147 if (next_offset >= RDP_MPPC_DICT_SIZE)
148 return -1;
149 dict[next_offset++] = (uint8) (walker >> 24 | 0x80);
150 walker <<= 8;
151 walker_len -= 8;
152 continue;
153 }
154
155 /* decode offset */
156 /* length pair */
157 walker <<= 1;
158 if (--walker_len < (big ? 3 : 2))
159 {
160 if (i >= clen)
161 return -1;
162 walker |= (data[i++] & 0xff) << (24 - walker_len);
163 walker_len += 8;
164 }
165
166 if (big)
167 {
168 /* offset decoding where offset len is:
169 -63: 11111 followed by the lower 6 bits of the value
170 64-319: 11110 followed by the lower 8 bits of the value ( value - 64 )
171 320-2367: 1110 followed by lower 11 bits of the value ( value - 320 )
172 2368-65535: 110 followed by lower 16 bits of the value ( value - 2368 )
173 */
174 switch (((uint32) walker) >> ((uint32) 29))
175 {
176 case 7: /* - 63 */
177 for (; walker_len < 9; walker_len += 8)
178 {
179 if (i >= clen)
180 return -1;
181 walker |= (data[i++] & 0xff) << (24 - walker_len);
182 }
183 walker <<= 3;
184 match_off = ((uint32) walker) >> ((uint32) 26);
185 walker <<= 6;
186 walker_len -= 9;
187 break;
188
189 case 6: /* 64 - 319 */
190 for (; walker_len < 11; walker_len += 8)
191 {
192 if (i >= clen)
193 return -1;
194 walker |= (data[i++] & 0xff) << (24 - walker_len);
195 }
196
197 walker <<= 3;
198 match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
199 walker <<= 8;
200 walker_len -= 11;
201 break;
202
203 case 5:
204 case 4: /* 320 - 2367 */
205 for (; walker_len < 13; walker_len += 8)
206 {
207 if (i >= clen)
208 return -1;
209 walker |= (data[i++] & 0xff) << (24 - walker_len);
210 }
211
212 walker <<= 2;
213 match_off = (((uint32) walker) >> ((uint32) 21)) + 320;
214 walker <<= 11;
215 walker_len -= 13;
216 break;
217
218 default: /* 2368 - 65535 */
219 for (; walker_len < 17; walker_len += 8)
220 {
221 if (i >= clen)
222 return -1;
223 walker |= (data[i++] & 0xff) << (24 - walker_len);
224 }
225
226 walker <<= 1;
227 match_off = (((uint32) walker) >> ((uint32) 16)) + 2368;
228 walker <<= 16;
229 walker_len -= 17;
230 break;
231 }
232 }
233 else
234 {
235 /* offset decoding where offset len is:
236 -63: 1111 followed by the lower 6 bits of the value
237 64-319: 1110 followed by the lower 8 bits of the value ( value - 64 )
238 320-8191: 110 followed by the lower 13 bits of the value ( value - 320 )
239 */
240 switch (((uint32) walker) >> ((uint32) 30))
241 {
242 case 3: /* - 63 */
243 if (walker_len < 8)
244 {
245 if (i >= clen)
246 return -1;
247 walker |= (data[i++] & 0xff) << (24 - walker_len);
248 walker_len += 8;
249 }
250 walker <<= 2;
251 match_off = ((uint32) walker) >> ((uint32) 26);
252 walker <<= 6;
253 walker_len -= 8;
254 break;
255
256 case 2: /* 64 - 319 */
257 for (; walker_len < 10; walker_len += 8)
258 {
259 if (i >= clen)
260 return -1;
261 walker |= (data[i++] & 0xff) << (24 - walker_len);
262 }
263
264 walker <<= 2;
265 match_off = (((uint32) walker) >> ((uint32) 24)) + 64;
266 walker <<= 8;
267 walker_len -= 10;
268 break;
269
270 default: /* 320 - 8191 */
271 for (; walker_len < 14; walker_len += 8)
272 {
273 if (i >= clen)
274 return -1;
275 walker |= (data[i++] & 0xff) << (24 - walker_len);
276 }
277
278 match_off = (walker >> 18) + 320;
279 walker <<= 14;
280 walker_len -= 14;
281 break;
282 }
283 }
284 if (walker_len == 0)
285 {
286 if (i >= clen)
287 return -1;
288 walker = data[i++] << 24;
289 walker_len = 8;
290 }
291
292 /* decode length of match */
293 match_len = 0;
294 if (walker >= 0)
295 { /* special case - length of 3 is in bit 0 */
296 match_len = 3;
297 walker <<= 1;
298 walker_len--;
299 }
300 else
301 {
302 /* this is how it works len of:
303 4-7: 10 followed by 2 bits of the value
304 8-15: 110 followed by 3 bits of the value
305 16-31: 1110 followed by 4 bits of the value
306 32-63: .... and so forth
307 64-127:
308 128-255:
309 256-511:
310 512-1023:
311 1024-2047:
312 2048-4095:
313 4096-8191:
314
315 i.e. 4097 is encoded as: 111111111110 000000000001
316 meaning 4096 + 1...
317 */
318 match_bits = big ? 14 : 11; /* 11 or 14 bits of value at most */
319 do
320 {
321 walker <<= 1;
322 if (--walker_len == 0)
323 {
324 if (i >= clen)
325 return -1;
326 walker = data[i++] << 24;
327 walker_len = 8;
328 }
329 if (walker >= 0)
330 break;
331 if (--match_bits == 0)
332 {
333 return -1;
334 }
335 }
336 while (1);
337 match_len = (big ? 16 : 13) - match_bits;
338 walker <<= 1;
339 if (--walker_len < match_len)
340 {
341 for (; walker_len < match_len; walker_len += 8)
342 {
343 if (i >= clen)
344 {
345 return -1;
346 }
347 walker |= (data[i++] & 0xff) << (24 - walker_len);
348 }
349 }
350
351 match_bits = match_len;
352 match_len =
353 ((walker >> (32 - match_bits)) & (~(-1 << match_bits))) | (1 <<
354 match_bits);
355 walker <<= match_bits;
356 walker_len -= match_bits;
357 }
358 if (next_offset + match_len >= RDP_MPPC_DICT_SIZE)
359 {
360 return -1;
361 }
362 /* memory areas can overlap - meaning we can't use memXXX functions */
363 k = (next_offset - match_off) & (big ? 65535 : 8191);
364 do
365 {
366 dict[next_offset++] = dict[k++];
367 }
368 while (--match_len != 0);
369 }
370 while (1);
371
372 /* store history offset */
373 g_mppc_dict.roff = next_offset;
374
375 *roff = old_offset;
376 *rlen = next_offset - old_offset;
377
378 return 0;
379}
RDP_MPPC_RESET
#define RDP_MPPC_RESET
Definition: constants.h:356
RDP_MPPC_DICT_SIZE
#define RDP_MPPC_DICT_SIZE
Definition: constants.h:358
RDP_MPPC_COMPRESSED
#define RDP_MPPC_COMPRESSED
Definition: constants.h:355
RDP_MPPC_BIG
#define RDP_MPPC_BIG
Definition: constants.h:354
RDP_MPPC_FLUSH
#define RDP_MPPC_FLUSH
Definition: constants.h:357
g_mppc_dict
RDPCOMP g_mppc_dict
Definition: mppc.c:55
uint32
unsigned int uint32
Definition: types.h:32
False
#define False
Definition: types.h:25
RD_BOOL
int RD_BOOL
Definition: types.h:21
True
#define True
Definition: types.h:24
uint8
unsigned char uint8
Definition: types.h:28
ctype
Definition: _ctype.h:58
data
GLint GLenum GLsizei GLsizei GLsizei GLint GLsizei const GLvoid * data
Definition: gl.h:1950
i
GLsizei GLenum const GLvoid GLsizei GLenum GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLint GLint GLint GLshort GLshort GLshort GLubyte GLubyte GLubyte GLuint GLuint GLuint GLushort GLushort GLushort GLbyte GLbyte GLbyte GLbyte GLdouble GLdouble GLdouble GLdouble GLfloat GLfloat GLfloat GLfloat GLint GLint GLint GLint GLshort GLshort GLshort GLshort GLubyte GLubyte GLubyte GLubyte GLuint GLuint GLuint GLuint GLushort GLushort GLushort GLushort GLboolean const GLdouble const GLfloat const GLint const GLshort const GLbyte const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLdouble const GLfloat const GLfloat const GLint const GLint const GLshort const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort const GLdouble const GLfloat const GLint const GLshort GLenum GLenum GLenum GLfloat GLenum GLint GLenum GLenum GLenum GLfloat GLenum GLenum GLint GLenum GLfloat GLenum GLint GLint GLushort GLenum GLenum GLfloat GLenum GLenum GLint GLfloat const GLubyte GLenum GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLint GLint GLsizei GLsizei GLint GLenum GLenum const GLvoid GLenum GLenum const GLfloat GLenum GLenum const GLint GLenum GLenum const GLdouble GLenum GLenum const GLfloat GLenum GLenum const GLint GLsizei GLuint GLfloat GLuint GLbitfield GLfloat GLint GLuint GLboolean GLenum GLfloat GLenum GLbitfield GLenum GLfloat GLfloat GLint GLint const GLfloat GLenum GLfloat GLfloat GLint GLint GLfloat GLfloat GLint GLint const GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat GLint GLfloat GLfloat const GLdouble const GLfloat const GLdouble const GLfloat GLint i
Definition: glfuncs.h:248
k
int k
Definition: mpi.c:3369
memset
#define memset(x, y, z)
Definition: compat.h:39
_RDPCOMP::roff
uint32 roff
Definition: types.h:190
_RDPCOMP::hist
uint8 hist[RDP_MPPC_DICT_SIZE]
Definition: types.h:191

Referenced by process_data_pdu(), and rdp5_process().

Variable Documentation

◆ g_mppc_dict

RDPCOMP g_mppc_dict

Definition at line 55 of file mppc.c.

Referenced by mppc_expand(), process_data_pdu(), and rdp5_process().