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mppc.c
1
20#include <winpr/assert.h>
21#include <freerdp/config.h>
22
23#include <winpr/crt.h>
24#include <winpr/print.h>
25#include <winpr/stream.h>
26#include <winpr/bitstream.h>
27
28#include <freerdp/log.h>
29#include "mppc.h"
30
31#define TAG FREERDP_TAG("codec.mppc")
32
33//#define DEBUG_MPPC 1
34
35#define MPPC_MATCH_INDEX(_sym1, _sym2, _sym3) \
36 ((((MPPC_MATCH_TABLE[_sym3] << 16) + (MPPC_MATCH_TABLE[_sym2] << 8) + \
37 MPPC_MATCH_TABLE[_sym1]) & \
38 0x07FFF000) >> \
39 12)
40
41struct s_MPPC_CONTEXT
42{
43 ALIGN64 wBitStream* bs;
44 ALIGN64 BOOL Compressor;
45 ALIGN64 BYTE* HistoryPtr;
46 ALIGN64 UINT32 HistoryOffset;
47 ALIGN64 UINT32 HistoryBufferSize;
48 ALIGN64 BYTE HistoryBuffer[65536];
49 ALIGN64 UINT16 MatchBuffer[32768];
50 ALIGN64 UINT32 CompressionLevel;
51};
52
53static const UINT32 MPPC_MATCH_TABLE[256] = {
54 0x00000000, 0x009CCF93, 0x01399F26, 0x01D66EB9, 0x02733E4C, 0x03100DDF, 0x03ACDD72, 0x0449AD05,
55 0x04E67C98, 0x05834C2B, 0x06201BBE, 0x06BCEB51, 0x0759BAE4, 0x07F68A77, 0x08935A0A, 0x0930299D,
56 0x09CCF930, 0x0A69C8C3, 0x0B069856, 0x0BA367E9, 0x0C40377C, 0x0CDD070F, 0x0D79D6A2, 0x0E16A635,
57 0x0EB375C8, 0x0F50455B, 0x0FED14EE, 0x1089E481, 0x1126B414, 0x11C383A7, 0x1260533A, 0x12FD22CD,
58 0x1399F260, 0x1436C1F3, 0x14D39186, 0x15706119, 0x160D30AC, 0x16AA003F, 0x1746CFD2, 0x17E39F65,
59 0x18806EF8, 0x191D3E8B, 0x19BA0E1E, 0x1A56DDB1, 0x1AF3AD44, 0x1B907CD7, 0x1C2D4C6A, 0x1CCA1BFD,
60 0x1D66EB90, 0x1E03BB23, 0x1EA08AB6, 0x1F3D5A49, 0x1FDA29DC, 0x2076F96F, 0x2113C902, 0x21B09895,
61 0x224D6828, 0x22EA37BB, 0x2387074E, 0x2423D6E1, 0x24C0A674, 0x255D7607, 0x25FA459A, 0x2697152D,
62 0x2733E4C0, 0x27D0B453, 0x286D83E6, 0x290A5379, 0x29A7230C, 0x2A43F29F, 0x2AE0C232, 0x2B7D91C5,
63 0x2C1A6158, 0x2CB730EB, 0x2D54007E, 0x2DF0D011, 0x2E8D9FA4, 0x2F2A6F37, 0x2FC73ECA, 0x30640E5D,
64 0x3100DDF0, 0x319DAD83, 0x323A7D16, 0x32D74CA9, 0x33741C3C, 0x3410EBCF, 0x34ADBB62, 0x354A8AF5,
65 0x35E75A88, 0x36842A1B, 0x3720F9AE, 0x37BDC941, 0x385A98D4, 0x38F76867, 0x399437FA, 0x3A31078D,
66 0x3ACDD720, 0x3B6AA6B3, 0x3C077646, 0x3CA445D9, 0x3D41156C, 0x3DDDE4FF, 0x3E7AB492, 0x3F178425,
67 0x3FB453B8, 0x4051234B, 0x40EDF2DE, 0x418AC271, 0x42279204, 0x42C46197, 0x4361312A, 0x43FE00BD,
68 0x449AD050, 0x45379FE3, 0x45D46F76, 0x46713F09, 0x470E0E9C, 0x47AADE2F, 0x4847ADC2, 0x48E47D55,
69 0x49814CE8, 0x4A1E1C7B, 0x4ABAEC0E, 0x4B57BBA1, 0x4BF48B34, 0x4C915AC7, 0x4D2E2A5A, 0x4DCAF9ED,
70 0x4E67C980, 0x4F049913, 0x4FA168A6, 0x503E3839, 0x50DB07CC, 0x5177D75F, 0x5214A6F2, 0x52B17685,
71 0x534E4618, 0x53EB15AB, 0x5487E53E, 0x5524B4D1, 0x55C18464, 0x565E53F7, 0x56FB238A, 0x5797F31D,
72 0x5834C2B0, 0x58D19243, 0x596E61D6, 0x5A0B3169, 0x5AA800FC, 0x5B44D08F, 0x5BE1A022, 0x5C7E6FB5,
73 0x5D1B3F48, 0x5DB80EDB, 0x5E54DE6E, 0x5EF1AE01, 0x5F8E7D94, 0x602B4D27, 0x60C81CBA, 0x6164EC4D,
74 0x6201BBE0, 0x629E8B73, 0x633B5B06, 0x63D82A99, 0x6474FA2C, 0x6511C9BF, 0x65AE9952, 0x664B68E5,
75 0x66E83878, 0x6785080B, 0x6821D79E, 0x68BEA731, 0x695B76C4, 0x69F84657, 0x6A9515EA, 0x6B31E57D,
76 0x6BCEB510, 0x6C6B84A3, 0x6D085436, 0x6DA523C9, 0x6E41F35C, 0x6EDEC2EF, 0x6F7B9282, 0x70186215,
77 0x70B531A8, 0x7152013B, 0x71EED0CE, 0x728BA061, 0x73286FF4, 0x73C53F87, 0x74620F1A, 0x74FEDEAD,
78 0x759BAE40, 0x76387DD3, 0x76D54D66, 0x77721CF9, 0x780EEC8C, 0x78ABBC1F, 0x79488BB2, 0x79E55B45,
79 0x7A822AD8, 0x7B1EFA6B, 0x7BBBC9FE, 0x7C589991, 0x7CF56924, 0x7D9238B7, 0x7E2F084A, 0x7ECBD7DD,
80 0x7F68A770, 0x80057703, 0x80A24696, 0x813F1629, 0x81DBE5BC, 0x8278B54F, 0x831584E2, 0x83B25475,
81 0x844F2408, 0x84EBF39B, 0x8588C32E, 0x862592C1, 0x86C26254, 0x875F31E7, 0x87FC017A, 0x8898D10D,
82 0x8935A0A0, 0x89D27033, 0x8A6F3FC6, 0x8B0C0F59, 0x8BA8DEEC, 0x8C45AE7F, 0x8CE27E12, 0x8D7F4DA5,
83 0x8E1C1D38, 0x8EB8ECCB, 0x8F55BC5E, 0x8FF28BF1, 0x908F5B84, 0x912C2B17, 0x91C8FAAA, 0x9265CA3D,
84 0x930299D0, 0x939F6963, 0x943C38F6, 0x94D90889, 0x9575D81C, 0x9612A7AF, 0x96AF7742, 0x974C46D5,
85 0x97E91668, 0x9885E5FB, 0x9922B58E, 0x99BF8521, 0x9A5C54B4, 0x9AF92447, 0x9B95F3DA, 0x9C32C36D
86};
87
88int mppc_decompress(MPPC_CONTEXT* mppc, const BYTE* pSrcData, UINT32 SrcSize,
89 const BYTE** ppDstData, UINT32* pDstSize, UINT32 flags)
90{
91 BYTE Literal = 0;
92 BYTE* SrcPtr = NULL;
93 UINT32 CopyOffset = 0;
94 UINT32 LengthOfMatch = 0;
95 UINT32 accumulator = 0;
96 BYTE* HistoryPtr = NULL;
97 BYTE* HistoryBuffer = NULL;
98 BYTE* HistoryBufferEnd = NULL;
99 UINT32 HistoryBufferSize = 0;
100 UINT32 CompressionLevel = 0;
101 wBitStream* bs = NULL;
102
103 WINPR_ASSERT(mppc);
104 WINPR_ASSERT(pSrcData);
105 WINPR_ASSERT(ppDstData);
106 WINPR_ASSERT(pDstSize);
107
108 bs = mppc->bs;
109 WINPR_ASSERT(bs);
110
111 HistoryBuffer = mppc->HistoryBuffer;
112 WINPR_ASSERT(HistoryBuffer);
113
114 HistoryBufferSize = mppc->HistoryBufferSize;
115 HistoryBufferEnd = &HistoryBuffer[HistoryBufferSize - 1];
116 CompressionLevel = mppc->CompressionLevel;
117 BitStream_Attach(bs, pSrcData, SrcSize);
118 BitStream_Fetch(bs);
119
120 if (flags & PACKET_AT_FRONT)
121 {
122 mppc->HistoryOffset = 0;
123 mppc->HistoryPtr = HistoryBuffer;
124 }
125
126 if (flags & PACKET_FLUSHED)
127 {
128 mppc->HistoryOffset = 0;
129 mppc->HistoryPtr = HistoryBuffer;
130 ZeroMemory(HistoryBuffer, mppc->HistoryBufferSize);
131 }
132
133 HistoryPtr = mppc->HistoryPtr;
134
135 if (!(flags & PACKET_COMPRESSED))
136 {
137 *pDstSize = SrcSize;
138 *ppDstData = pSrcData;
139 return 1;
140 }
141
142 while ((bs->length - bs->position) >= 8)
143 {
144 accumulator = bs->accumulator;
145
150 if (HistoryPtr > HistoryBufferEnd)
151 {
152 WLog_ERR(TAG, "history buffer index out of range");
153 return -1004;
154 }
155
156 if ((accumulator & 0x80000000) == 0x00000000)
157 {
162 Literal = ((accumulator & 0x7F000000) >> 24);
163 *(HistoryPtr) = Literal;
164 HistoryPtr++;
165 BitStream_Shift(bs, 8);
166 continue;
167 }
168 else if ((accumulator & 0xC0000000) == 0x80000000)
169 {
174 Literal = ((accumulator & 0x3F800000) >> 23) + 0x80;
175 *(HistoryPtr) = Literal;
176 HistoryPtr++;
177 BitStream_Shift(bs, 9);
178 continue;
179 }
180
184 if (CompressionLevel) /* RDP5 */
185 {
186 if ((accumulator & 0xF8000000) == 0xF8000000)
187 {
192 CopyOffset = ((accumulator >> 21) & 0x3F);
193 BitStream_Shift(bs, 11);
194 }
195 else if ((accumulator & 0xF8000000) == 0xF0000000)
196 {
201 CopyOffset = ((accumulator >> 19) & 0xFF) + 64;
202 BitStream_Shift(bs, 13);
203 }
204 else if ((accumulator & 0xF0000000) == 0xE0000000)
205 {
210 CopyOffset = ((accumulator >> 17) & 0x7FF) + 320;
211 BitStream_Shift(bs, 15);
212 }
213 else if ((accumulator & 0xE0000000) == 0xC0000000)
214 {
219 CopyOffset = ((accumulator >> 13) & 0xFFFF) + 2368;
220 BitStream_Shift(bs, 19);
221 }
222 else
223 {
224 /* Invalid CopyOffset Encoding */
225 return -1001;
226 }
227 }
228 else /* RDP4 */
229 {
230 if ((accumulator & 0xF0000000) == 0xF0000000)
231 {
236 CopyOffset = ((accumulator >> 22) & 0x3F);
237 BitStream_Shift(bs, 10);
238 }
239 else if ((accumulator & 0xF0000000) == 0xE0000000)
240 {
245 CopyOffset = ((accumulator >> 20) & 0xFF) + 64;
246 BitStream_Shift(bs, 12);
247 }
248 else if ((accumulator & 0xE0000000) == 0xC0000000)
249 {
254 CopyOffset = ((accumulator >> 16) & 0x1FFF) + 320;
255 BitStream_Shift(bs, 16);
256 }
257 else
258 {
259 /* Invalid CopyOffset Encoding */
260 return -1002;
261 }
262 }
263
267 accumulator = bs->accumulator;
268
269 if ((accumulator & 0x80000000) == 0x00000000)
270 {
275 LengthOfMatch = 3;
276 BitStream_Shift(bs, 1);
277 }
278 else if ((accumulator & 0xC0000000) == 0x80000000)
279 {
284 LengthOfMatch = ((accumulator >> 28) & 0x0003) + 0x0004;
285 BitStream_Shift(bs, 4);
286 }
287 else if ((accumulator & 0xE0000000) == 0xC0000000)
288 {
293 LengthOfMatch = ((accumulator >> 26) & 0x0007) + 0x0008;
294 BitStream_Shift(bs, 6);
295 }
296 else if ((accumulator & 0xF0000000) == 0xE0000000)
297 {
302 LengthOfMatch = ((accumulator >> 24) & 0x000F) + 0x0010;
303 BitStream_Shift(bs, 8);
304 }
305 else if ((accumulator & 0xF8000000) == 0xF0000000)
306 {
311 LengthOfMatch = ((accumulator >> 22) & 0x001F) + 0x0020;
312 BitStream_Shift(bs, 10);
313 }
314 else if ((accumulator & 0xFC000000) == 0xF8000000)
315 {
320 LengthOfMatch = ((accumulator >> 20) & 0x003F) + 0x0040;
321 BitStream_Shift(bs, 12);
322 }
323 else if ((accumulator & 0xFE000000) == 0xFC000000)
324 {
329 LengthOfMatch = ((accumulator >> 18) & 0x007F) + 0x0080;
330 BitStream_Shift(bs, 14);
331 }
332 else if ((accumulator & 0xFF000000) == 0xFE000000)
333 {
338 LengthOfMatch = ((accumulator >> 16) & 0x00FF) + 0x0100;
339 BitStream_Shift(bs, 16);
340 }
341 else if ((accumulator & 0xFF800000) == 0xFF000000)
342 {
347 LengthOfMatch = ((accumulator >> 14) & 0x01FF) + 0x0200;
348 BitStream_Shift(bs, 18);
349 }
350 else if ((accumulator & 0xFFC00000) == 0xFF800000)
351 {
356 LengthOfMatch = ((accumulator >> 12) & 0x03FF) + 0x0400;
357 BitStream_Shift(bs, 20);
358 }
359 else if ((accumulator & 0xFFE00000) == 0xFFC00000)
360 {
365 LengthOfMatch = ((accumulator >> 10) & 0x07FF) + 0x0800;
366 BitStream_Shift(bs, 22);
367 }
368 else if ((accumulator & 0xFFF00000) == 0xFFE00000)
369 {
374 LengthOfMatch = ((accumulator >> 8) & 0x0FFF) + 0x1000;
375 BitStream_Shift(bs, 24);
376 }
377 else if (((accumulator & 0xFFF80000) == 0xFFF00000) && CompressionLevel) /* RDP5 */
378 {
383 LengthOfMatch = ((accumulator >> 6) & 0x1FFF) + 0x2000;
384 BitStream_Shift(bs, 26);
385 }
386 else if (((accumulator & 0xFFFC0000) == 0xFFF80000) && CompressionLevel) /* RDP5 */
387 {
392 LengthOfMatch = ((accumulator >> 4) & 0x3FFF) + 0x4000;
393 BitStream_Shift(bs, 28);
394 }
395 else if (((accumulator & 0xFFFE0000) == 0xFFFC0000) && CompressionLevel) /* RDP5 */
396 {
401 LengthOfMatch = ((accumulator >> 2) & 0x7FFF) + 0x8000;
402 BitStream_Shift(bs, 30);
403 }
404 else
405 {
406 /* Invalid LengthOfMatch Encoding */
407 return -1003;
408 }
409
410#if defined(DEBUG_MPPC)
411 WLog_DBG(TAG, "<%" PRIu32 ",%" PRIu32 ">", CopyOffset, LengthOfMatch);
412#endif
413
414 if ((HistoryPtr + LengthOfMatch - 1) > HistoryBufferEnd)
415 {
416 WLog_ERR(TAG, "history buffer overflow");
417 return -1005;
418 }
419
420 SrcPtr = &HistoryBuffer[(HistoryPtr - HistoryBuffer - CopyOffset) &
421 (CompressionLevel ? 0xFFFF : 0x1FFF)];
422
423 do
424 {
425 *HistoryPtr++ = *SrcPtr++;
426 } while (--LengthOfMatch);
427 }
428
429 *pDstSize = (UINT32)(HistoryPtr - mppc->HistoryPtr);
430 *ppDstData = mppc->HistoryPtr;
431 mppc->HistoryPtr = HistoryPtr;
432 return 1;
433}
434
435int mppc_compress(MPPC_CONTEXT* mppc, const BYTE* pSrcData, UINT32 SrcSize, BYTE* pDstBuffer,
436 const BYTE** ppDstData, UINT32* pDstSize, UINT32* pFlags)
437{
438 const BYTE* pSrcPtr = NULL;
439 const BYTE* pSrcEnd = NULL;
440 BYTE* MatchPtr = NULL;
441 UINT32 DstSize = 0;
442 BYTE* pDstData = NULL;
443 UINT32 MatchIndex = 0;
444 UINT32 accumulator = 0;
445 BOOL PacketFlushed = 0;
446 BOOL PacketAtFront = 0;
447 DWORD CopyOffset = 0;
448 DWORD LengthOfMatch = 0;
449 BYTE* HistoryBuffer = NULL;
450 BYTE* HistoryPtr = NULL;
451 UINT32 HistoryOffset = 0;
452 UINT32 HistoryBufferSize = 0;
453 BYTE Sym1 = 0;
454 BYTE Sym2 = 0;
455 BYTE Sym3 = 0;
456 UINT32 CompressionLevel = 0;
457 wBitStream* bs = NULL;
458
459 WINPR_ASSERT(mppc);
460 WINPR_ASSERT(pSrcData);
461 WINPR_ASSERT(pDstBuffer);
462 WINPR_ASSERT(ppDstData);
463 WINPR_ASSERT(pDstSize);
464 WINPR_ASSERT(pFlags);
465
466 bs = mppc->bs;
467 WINPR_ASSERT(bs);
468
469 HistoryBuffer = mppc->HistoryBuffer;
470 WINPR_ASSERT(HistoryBuffer);
471
472 HistoryBufferSize = mppc->HistoryBufferSize;
473 CompressionLevel = mppc->CompressionLevel;
474 HistoryOffset = mppc->HistoryOffset;
475 *pFlags = 0;
476 PacketFlushed = FALSE;
477
478 if (((HistoryOffset + SrcSize) < (HistoryBufferSize - 3)) && HistoryOffset)
479 {
480 PacketAtFront = FALSE;
481 }
482 else
483 {
484 if (HistoryOffset == (HistoryBufferSize + 1))
485 PacketFlushed = TRUE;
486
487 HistoryOffset = 0;
488 PacketAtFront = TRUE;
489 }
490
491 HistoryPtr = &(HistoryBuffer[HistoryOffset]);
492 pDstData = pDstBuffer;
493 *ppDstData = pDstBuffer;
494
495 if (!pDstData)
496 return -1;
497
498 if (*pDstSize > SrcSize)
499 DstSize = SrcSize;
500 else
501 DstSize = *pDstSize;
502
503 BitStream_Attach(bs, pDstData, DstSize);
504 pSrcPtr = pSrcData;
505 pSrcEnd = &(pSrcData[SrcSize - 1]);
506
507 while (pSrcPtr < (pSrcEnd - 2))
508 {
509 Sym1 = pSrcPtr[0];
510 Sym2 = pSrcPtr[1];
511 Sym3 = pSrcPtr[2];
512 *HistoryPtr++ = *pSrcPtr++;
513 MatchIndex = MPPC_MATCH_INDEX(Sym1, Sym2, Sym3);
514 MatchPtr = &(HistoryBuffer[mppc->MatchBuffer[MatchIndex]]);
515
516 if (MatchPtr != (HistoryPtr - 1))
517 mppc->MatchBuffer[MatchIndex] = (UINT16)(HistoryPtr - HistoryBuffer);
518
519 if (mppc->HistoryPtr < HistoryPtr)
520 mppc->HistoryPtr = HistoryPtr;
521
522 if ((Sym1 != *(MatchPtr - 1)) || (Sym2 != MatchPtr[0]) || (Sym3 != MatchPtr[1]) ||
523 (&MatchPtr[1] > mppc->HistoryPtr) || (MatchPtr == HistoryBuffer) ||
524 (MatchPtr == (HistoryPtr - 1)) || (MatchPtr == HistoryPtr))
525 {
526 if (((bs->position / 8) + 2) > (DstSize - 1))
527 {
528 mppc_context_reset(mppc, TRUE);
529 *pFlags |= PACKET_FLUSHED;
530 *pFlags |= CompressionLevel;
531 *ppDstData = pSrcData;
532 *pDstSize = SrcSize;
533 return 1;
534 }
535
536 accumulator = Sym1;
537#if defined(DEBUG_MPPC)
538 WLog_DBG(TAG, "%" PRIu32 "", accumulator);
539#endif
540
541 if (accumulator < 0x80)
542 {
543 /* 8 bits of literal are encoded as-is */
544 BitStream_Write_Bits(bs, accumulator, 8);
545 }
546 else
547 {
548 /* bits 10 followed by lower 7 bits of literal */
549 accumulator = 0x100 | (accumulator & 0x7F);
550 BitStream_Write_Bits(bs, accumulator, 9);
551 }
552 }
553 else
554 {
555 CopyOffset = (HistoryBufferSize - 1) & (HistoryPtr - MatchPtr);
556 *HistoryPtr++ = Sym2;
557 *HistoryPtr++ = Sym3;
558 pSrcPtr += 2;
559 LengthOfMatch = 3;
560 MatchPtr += 2;
561
562 while ((*pSrcPtr == *MatchPtr) && (pSrcPtr < pSrcEnd) && (MatchPtr <= mppc->HistoryPtr))
563 {
564 MatchPtr++;
565 *HistoryPtr++ = *pSrcPtr++;
566 LengthOfMatch++;
567 }
568
569#if defined(DEBUG_MPPC)
570 WLog_DBG(TAG, "<%" PRIu32 ",%" PRIu32 ">", CopyOffset, LengthOfMatch);
571#endif
572
573 /* Encode CopyOffset */
574
575 if (((bs->position / 8) + 7) > (DstSize - 1))
576 {
577 mppc_context_reset(mppc, TRUE);
578 *pFlags |= PACKET_FLUSHED;
579 *pFlags |= CompressionLevel;
580 *ppDstData = pSrcData;
581 *pDstSize = SrcSize;
582 return 1;
583 }
584
585 if (CompressionLevel) /* RDP5 */
586 {
587 if (CopyOffset < 64)
588 {
589 /* bits 11111 + lower 6 bits of CopyOffset */
590 accumulator = 0x07C0 | (CopyOffset & 0x003F);
591 BitStream_Write_Bits(bs, accumulator, 11);
592 }
593 else if ((CopyOffset >= 64) && (CopyOffset < 320))
594 {
595 /* bits 11110 + lower 8 bits of (CopyOffset - 64) */
596 accumulator = 0x1E00 | ((CopyOffset - 64) & 0x00FF);
597 BitStream_Write_Bits(bs, accumulator, 13);
598 }
599 else if ((CopyOffset >= 320) && (CopyOffset < 2368))
600 {
601 /* bits 1110 + lower 11 bits of (CopyOffset - 320) */
602 accumulator = 0x7000 | ((CopyOffset - 320) & 0x07FF);
603 BitStream_Write_Bits(bs, accumulator, 15);
604 }
605 else
606 {
607 /* bits 110 + lower 16 bits of (CopyOffset - 2368) */
608 accumulator = 0x060000 | ((CopyOffset - 2368) & 0xFFFF);
609 BitStream_Write_Bits(bs, accumulator, 19);
610 }
611 }
612 else /* RDP4 */
613 {
614 if (CopyOffset < 64)
615 {
616 /* bits 1111 + lower 6 bits of CopyOffset */
617 accumulator = 0x03C0 | (CopyOffset & 0x003F);
618 BitStream_Write_Bits(bs, accumulator, 10);
619 }
620 else if ((CopyOffset >= 64) && (CopyOffset < 320))
621 {
622 /* bits 1110 + lower 8 bits of (CopyOffset - 64) */
623 accumulator = 0x0E00 | ((CopyOffset - 64) & 0x00FF);
624 BitStream_Write_Bits(bs, accumulator, 12);
625 }
626 else if ((CopyOffset >= 320) && (CopyOffset < 8192))
627 {
628 /* bits 110 + lower 13 bits of (CopyOffset - 320) */
629 accumulator = 0xC000 | ((CopyOffset - 320) & 0x1FFF);
630 BitStream_Write_Bits(bs, accumulator, 16);
631 }
632 }
633
634 /* Encode LengthOfMatch */
635
636 if (LengthOfMatch == 3)
637 {
638 /* 0 + 0 lower bits of LengthOfMatch */
639 BitStream_Write_Bits(bs, 0, 1);
640 }
641 else if ((LengthOfMatch >= 4) && (LengthOfMatch < 8))
642 {
643 /* 10 + 2 lower bits of LengthOfMatch */
644 accumulator = 0x0008 | (LengthOfMatch & 0x0003);
645 BitStream_Write_Bits(bs, accumulator, 4);
646 }
647 else if ((LengthOfMatch >= 8) && (LengthOfMatch < 16))
648 {
649 /* 110 + 3 lower bits of LengthOfMatch */
650 accumulator = 0x0030 | (LengthOfMatch & 0x0007);
651 BitStream_Write_Bits(bs, accumulator, 6);
652 }
653 else if ((LengthOfMatch >= 16) && (LengthOfMatch < 32))
654 {
655 /* 1110 + 4 lower bits of LengthOfMatch */
656 accumulator = 0x00E0 | (LengthOfMatch & 0x000F);
657 BitStream_Write_Bits(bs, accumulator, 8);
658 }
659 else if ((LengthOfMatch >= 32) && (LengthOfMatch < 64))
660 {
661 /* 11110 + 5 lower bits of LengthOfMatch */
662 accumulator = 0x03C0 | (LengthOfMatch & 0x001F);
663 BitStream_Write_Bits(bs, accumulator, 10);
664 }
665 else if ((LengthOfMatch >= 64) && (LengthOfMatch < 128))
666 {
667 /* 111110 + 6 lower bits of LengthOfMatch */
668 accumulator = 0x0F80 | (LengthOfMatch & 0x003F);
669 BitStream_Write_Bits(bs, accumulator, 12);
670 }
671 else if ((LengthOfMatch >= 128) && (LengthOfMatch < 256))
672 {
673 /* 1111110 + 7 lower bits of LengthOfMatch */
674 accumulator = 0x3F00 | (LengthOfMatch & 0x007F);
675 BitStream_Write_Bits(bs, accumulator, 14);
676 }
677 else if ((LengthOfMatch >= 256) && (LengthOfMatch < 512))
678 {
679 /* 11111110 + 8 lower bits of LengthOfMatch */
680 accumulator = 0xFE00 | (LengthOfMatch & 0x00FF);
681 BitStream_Write_Bits(bs, accumulator, 16);
682 }
683 else if ((LengthOfMatch >= 512) && (LengthOfMatch < 1024))
684 {
685 /* 111111110 + 9 lower bits of LengthOfMatch */
686 accumulator = 0x3FC00 | (LengthOfMatch & 0x01FF);
687 BitStream_Write_Bits(bs, accumulator, 18);
688 }
689 else if ((LengthOfMatch >= 1024) && (LengthOfMatch < 2048))
690 {
691 /* 1111111110 + 10 lower bits of LengthOfMatch */
692 accumulator = 0xFF800 | (LengthOfMatch & 0x03FF);
693 BitStream_Write_Bits(bs, accumulator, 20);
694 }
695 else if ((LengthOfMatch >= 2048) && (LengthOfMatch < 4096))
696 {
697 /* 11111111110 + 11 lower bits of LengthOfMatch */
698 accumulator = 0x3FF000 | (LengthOfMatch & 0x07FF);
699 BitStream_Write_Bits(bs, accumulator, 22);
700 }
701 else if ((LengthOfMatch >= 4096) && (LengthOfMatch < 8192))
702 {
703 /* 111111111110 + 12 lower bits of LengthOfMatch */
704 accumulator = 0xFFE000 | (LengthOfMatch & 0x0FFF);
705 BitStream_Write_Bits(bs, accumulator, 24);
706 }
707 else if (((LengthOfMatch >= 8192) && (LengthOfMatch < 16384)) &&
708 CompressionLevel) /* RDP5 */
709 {
710 /* 1111111111110 + 13 lower bits of LengthOfMatch */
711 accumulator = 0x3FFC000 | (LengthOfMatch & 0x1FFF);
712 BitStream_Write_Bits(bs, accumulator, 26);
713 }
714 else if (((LengthOfMatch >= 16384) && (LengthOfMatch < 32768)) &&
715 CompressionLevel) /* RDP5 */
716 {
717 /* 11111111111110 + 14 lower bits of LengthOfMatch */
718 accumulator = 0xFFF8000 | (LengthOfMatch & 0x3FFF);
719 BitStream_Write_Bits(bs, accumulator, 28);
720 }
721 else if (((LengthOfMatch >= 32768) && (LengthOfMatch < 65536)) &&
722 CompressionLevel) /* RDP5 */
723 {
724 /* 111111111111110 + 15 lower bits of LengthOfMatch */
725 accumulator = 0x3FFF0000 | (LengthOfMatch & 0x7FFF);
726 BitStream_Write_Bits(bs, accumulator, 30);
727 }
728 }
729 }
730
731 /* Encode trailing symbols as literals */
732
733 while (pSrcPtr <= pSrcEnd)
734 {
735 if (((bs->position / 8) + 2) > (DstSize - 1))
736 {
737 mppc_context_reset(mppc, TRUE);
738 *pFlags |= PACKET_FLUSHED;
739 *pFlags |= CompressionLevel;
740 *ppDstData = pSrcData;
741 *pDstSize = SrcSize;
742 return 1;
743 }
744
745 accumulator = *pSrcPtr;
746#if defined(DEBUG_MPPC)
747 WLog_DBG(TAG, "%" PRIu32 "", accumulator);
748#endif
749
750 if (accumulator < 0x80)
751 {
752 /* 8 bits of literal are encoded as-is */
753 BitStream_Write_Bits(bs, accumulator, 8);
754 }
755 else
756 {
757 /* bits 10 followed by lower 7 bits of literal */
758 accumulator = 0x100 | (accumulator & 0x7F);
759 BitStream_Write_Bits(bs, accumulator, 9);
760 }
761
762 *HistoryPtr++ = *pSrcPtr++;
763 }
764
765 BitStream_Flush(bs);
766 *pFlags |= PACKET_COMPRESSED;
767 *pFlags |= CompressionLevel;
768
769 if (PacketAtFront)
770 *pFlags |= PACKET_AT_FRONT;
771
772 if (PacketFlushed)
773 *pFlags |= PACKET_FLUSHED;
774
775 *pDstSize = ((bs->position + 7) / 8);
776 mppc->HistoryPtr = HistoryPtr;
777 const intptr_t diff = HistoryPtr - HistoryBuffer;
778 if (diff > UINT32_MAX)
779 return -1;
780 mppc->HistoryOffset = (UINT32)diff;
781 return 1;
782}
783
784void mppc_set_compression_level(MPPC_CONTEXT* mppc, DWORD CompressionLevel)
785{
786 WINPR_ASSERT(mppc);
787
788 if (CompressionLevel < 1)
789 {
790 mppc->CompressionLevel = 0;
791 mppc->HistoryBufferSize = 8192;
792 }
793 else
794 {
795 mppc->CompressionLevel = 1;
796 mppc->HistoryBufferSize = 65536;
797 }
798}
799
800void mppc_context_reset(MPPC_CONTEXT* mppc, BOOL flush)
801{
802 WINPR_ASSERT(mppc);
803
804 ZeroMemory(&(mppc->HistoryBuffer), sizeof(mppc->HistoryBuffer));
805 ZeroMemory(&(mppc->MatchBuffer), sizeof(mppc->MatchBuffer));
806
807 if (flush)
808 {
809 mppc->HistoryOffset = mppc->HistoryBufferSize + 1;
810 mppc->HistoryPtr = mppc->HistoryBuffer;
811 }
812 else
813 {
814 mppc->HistoryOffset = 0;
815 mppc->HistoryPtr = &(mppc->HistoryBuffer[mppc->HistoryOffset]);
816 }
817}
818
819MPPC_CONTEXT* mppc_context_new(DWORD CompressionLevel, BOOL Compressor)
820{
821 MPPC_CONTEXT* mppc = calloc(1, sizeof(MPPC_CONTEXT));
822
823 if (!mppc)
824 goto fail;
825
826 mppc->Compressor = Compressor;
827
828 if (CompressionLevel < 1)
829 {
830 mppc->CompressionLevel = 0;
831 mppc->HistoryBufferSize = 8192;
832 }
833 else
834 {
835 mppc->CompressionLevel = 1;
836 mppc->HistoryBufferSize = 65536;
837 }
838
839 mppc->bs = BitStream_New();
840
841 if (!mppc->bs)
842 goto fail;
843
844 mppc_context_reset(mppc, FALSE);
845
846 return mppc;
847
848fail:
849 mppc_context_free(mppc);
850 return NULL;
851}
852
853void mppc_context_free(MPPC_CONTEXT* mppc)
854{
855 if (mppc)
856 {
857 BitStream_Free(mppc->bs);
858 free(mppc);
859 }
860}