1 /* Ppmd7.c -- PPMdH codec
2 2010-03-12 : Igor Pavlov : Public domain
3 This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
4
5 #include <memory.h>
6
7 #include "Ppmd7.h"
8
9 const Byte PPMD7_kExpEscape[16] = { 25, 14, 9, 7, 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 2, 2 };
10 static const UInt16 kInitBinEsc[] = { 0x3CDD, 0x1F3F, 0x59BF, 0x48F3, 0x64A1, 0x5ABC, 0x6632, 0x6051};
11
12 #define MAX_FREQ 124
13 #define UNIT_SIZE 12
14
15 #define U2B(nu) ((UInt32)(nu) * UNIT_SIZE)
16 #define U2I(nu) (p->Units2Indx[(nu) - 1])
17 #define I2U(indx) (p->Indx2Units[indx])
18
19 #ifdef PPMD_32BIT
20 #define REF(ptr) (ptr)
21 #else
22 #define REF(ptr) ((UInt32)((Byte *)(ptr) - (p)->Base))
23 #endif
24
25 #define STATS_REF(ptr) ((CPpmd_State_Ref)REF(ptr))
26
27 #define CTX(ref) ((CPpmd7_Context *)Ppmd7_GetContext(p, ref))
28 #define STATS(ctx) Ppmd7_GetStats(p, ctx)
29 #define ONE_STATE(ctx) Ppmd7Context_OneState(ctx)
30 #define SUFFIX(ctx) CTX((ctx)->Suffix)
31
32 typedef CPpmd7_Context * CTX_PTR;
33
34 struct CPpmd7_Node_;
35
36 typedef
37 #ifdef PPMD_32BIT
38 struct CPpmd7_Node_ *
39 #else
40 UInt32
41 #endif
42 CPpmd7_Node_Ref;
43
44 typedef struct CPpmd7_Node_
45 {
46 UInt16 Stamp; /* must be at offset 0 as CPpmd7_Context::NumStats. Stamp=0 means free */
47 UInt16 NU;
48 CPpmd7_Node_Ref Next; /* must be at offset >= 4 */
49 CPpmd7_Node_Ref Prev;
50 } CPpmd7_Node;
51
52 #ifdef PPMD_32BIT
53 #define NODE(ptr) (ptr)
54 #else
55 #define NODE(offs) ((CPpmd7_Node *)(p->Base + (offs)))
56 #endif
57
Ppmd7_Construct(CPpmd7 * p)58 void Ppmd7_Construct(CPpmd7 *p)
59 {
60 unsigned i, k, m;
61
62 p->Base = 0;
63
64 for (i = 0, k = 0; i < PPMD_NUM_INDEXES; i++)
65 {
66 unsigned step = (i >= 12 ? 4 : (i >> 2) + 1);
67 do { p->Units2Indx[k++] = (Byte)i; } while(--step);
68 p->Indx2Units[i] = (Byte)k;
69 }
70
71 p->NS2BSIndx[0] = (0 << 1);
72 p->NS2BSIndx[1] = (1 << 1);
73 memset(p->NS2BSIndx + 2, (2 << 1), 9);
74 memset(p->NS2BSIndx + 11, (3 << 1), 256 - 11);
75
76 for (i = 0; i < 3; i++)
77 p->NS2Indx[i] = (Byte)i;
78 for (m = i, k = 1; i < 256; i++)
79 {
80 p->NS2Indx[i] = (Byte)m;
81 if (--k == 0)
82 k = (++m) - 2;
83 }
84
85 memset(p->HB2Flag, 0, 0x40);
86 memset(p->HB2Flag + 0x40, 8, 0x100 - 0x40);
87 }
88
Ppmd7_Free(CPpmd7 * p,ISzAlloc * alloc)89 void Ppmd7_Free(CPpmd7 *p, ISzAlloc *alloc)
90 {
91 alloc->Free(alloc, p->Base);
92 p->Size = 0;
93 p->Base = 0;
94 }
95
Ppmd7_Alloc(CPpmd7 * p,UInt32 size,ISzAlloc * alloc)96 Bool Ppmd7_Alloc(CPpmd7 *p, UInt32 size, ISzAlloc *alloc)
97 {
98 if (p->Base == 0 || p->Size != size)
99 {
100 Ppmd7_Free(p, alloc);
101 p->AlignOffset =
102 #ifdef PPMD_32BIT
103 (4 - size) & 3;
104 #else
105 4 - (size & 3);
106 #endif
107 if ((p->Base = (Byte *)alloc->Alloc(alloc, p->AlignOffset + size
108 #ifndef PPMD_32BIT
109 + UNIT_SIZE
110 #endif
111 )) == 0)
112 return False;
113 p->Size = size;
114 }
115 return True;
116 }
117
InsertNode(CPpmd7 * p,void * node,unsigned indx)118 static void InsertNode(CPpmd7 *p, void *node, unsigned indx)
119 {
120 *((CPpmd_Void_Ref *)node) = p->FreeList[indx];
121 p->FreeList[indx] = REF(node);
122 }
123
RemoveNode(CPpmd7 * p,unsigned indx)124 static void *RemoveNode(CPpmd7 *p, unsigned indx)
125 {
126 CPpmd_Void_Ref *node = (CPpmd_Void_Ref *)Ppmd7_GetPtr(p, p->FreeList[indx]);
127 p->FreeList[indx] = *node;
128 return node;
129 }
130
SplitBlock(CPpmd7 * p,void * ptr,unsigned oldIndx,unsigned newIndx)131 static void SplitBlock(CPpmd7 *p, void *ptr, unsigned oldIndx, unsigned newIndx)
132 {
133 unsigned i, nu = I2U(oldIndx) - I2U(newIndx);
134 ptr = (Byte *)ptr + U2B(I2U(newIndx));
135 if (I2U(i = U2I(nu)) != nu)
136 {
137 unsigned k = I2U(--i);
138 InsertNode(p, ((Byte *)ptr) + U2B(k), nu - k - 1);
139 }
140 InsertNode(p, ptr, i);
141 }
142
GlueFreeBlocks(CPpmd7 * p)143 static void GlueFreeBlocks(CPpmd7 *p)
144 {
145 #ifdef PPMD_32BIT
146 CPpmd7_Node headItem;
147 CPpmd7_Node_Ref head = &headItem;
148 #else
149 CPpmd7_Node_Ref head = p->AlignOffset + p->Size;
150 #endif
151
152 CPpmd7_Node_Ref n = head;
153 unsigned i;
154
155 p->GlueCount = 255;
156
157 /* create doubly-linked list of free blocks */
158 for (i = 0; i < PPMD_NUM_INDEXES; i++)
159 {
160 UInt16 nu = I2U(i);
161 CPpmd7_Node_Ref next = (CPpmd7_Node_Ref)p->FreeList[i];
162 p->FreeList[i] = 0;
163 while (next != 0)
164 {
165 CPpmd7_Node *node = NODE(next);
166 node->Next = n;
167 n = NODE(n)->Prev = next;
168 next = *(const CPpmd7_Node_Ref *)node;
169 node->Stamp = 0;
170 node->NU = (UInt16)nu;
171 }
172 }
173 NODE(head)->Stamp = 1;
174 NODE(head)->Next = n;
175 NODE(n)->Prev = head;
176 if (p->LoUnit != p->HiUnit)
177 ((CPpmd7_Node *)p->LoUnit)->Stamp = 1;
178
179 /* Glue free blocks */
180 while (n != head)
181 {
182 CPpmd7_Node *node = NODE(n);
183 UInt32 nu = (UInt32)node->NU;
184 for (;;)
185 {
186 CPpmd7_Node *node2 = NODE(n) + nu;
187 nu += node2->NU;
188 if (node2->Stamp != 0 || nu >= 0x10000)
189 break;
190 NODE(node2->Prev)->Next = node2->Next;
191 NODE(node2->Next)->Prev = node2->Prev;
192 node->NU = (UInt16)nu;
193 }
194 n = node->Next;
195 }
196
197 /* Fill lists of free blocks */
198 for (n = NODE(head)->Next; n != head;)
199 {
200 CPpmd7_Node *node = NODE(n);
201 unsigned nu;
202 CPpmd7_Node_Ref next = node->Next;
203 for (nu = node->NU; nu > 128; nu -= 128, node += 128)
204 InsertNode(p, node, PPMD_NUM_INDEXES - 1);
205 if (I2U(i = U2I(nu)) != nu)
206 {
207 unsigned k = I2U(--i);
208 InsertNode(p, node + k, nu - k - 1);
209 }
210 InsertNode(p, node, i);
211 n = next;
212 }
213 }
214
AllocUnitsRare(CPpmd7 * p,unsigned indx)215 static void *AllocUnitsRare(CPpmd7 *p, unsigned indx)
216 {
217 unsigned i;
218 void *retVal;
219 if (p->GlueCount == 0)
220 {
221 GlueFreeBlocks(p);
222 if (p->FreeList[indx] != 0)
223 return RemoveNode(p, indx);
224 }
225 i = indx;
226 do
227 {
228 if (++i == PPMD_NUM_INDEXES)
229 {
230 UInt32 numBytes = U2B(I2U(indx));
231 p->GlueCount--;
232 return ((UInt32)(p->UnitsStart - p->Text) > numBytes) ? (p->UnitsStart -= numBytes) : (NULL);
233 }
234 }
235 while (p->FreeList[i] == 0);
236 retVal = RemoveNode(p, i);
237 SplitBlock(p, retVal, i, indx);
238 return retVal;
239 }
240
AllocUnits(CPpmd7 * p,unsigned indx)241 static void *AllocUnits(CPpmd7 *p, unsigned indx)
242 {
243 UInt32 numBytes;
244 if (p->FreeList[indx] != 0)
245 return RemoveNode(p, indx);
246 numBytes = U2B(I2U(indx));
247 if (numBytes <= (UInt32)(p->HiUnit - p->LoUnit))
248 {
249 void *retVal = p->LoUnit;
250 p->LoUnit += numBytes;
251 return retVal;
252 }
253 return AllocUnitsRare(p, indx);
254 }
255
256 #define MyMem12Cpy(dest, src, num) \
257 { UInt32 *d = (UInt32 *)dest; const UInt32 *s = (const UInt32 *)src; UInt32 n = num; \
258 do { d[0] = s[0]; d[1] = s[1]; d[2] = s[2]; s += 3; d += 3; } while(--n); }
259
ShrinkUnits(CPpmd7 * p,void * oldPtr,unsigned oldNU,unsigned newNU)260 static void *ShrinkUnits(CPpmd7 *p, void *oldPtr, unsigned oldNU, unsigned newNU)
261 {
262 unsigned i0 = U2I(oldNU);
263 unsigned i1 = U2I(newNU);
264 if (i0 == i1)
265 return oldPtr;
266 if (p->FreeList[i1] != 0)
267 {
268 void *ptr = RemoveNode(p, i1);
269 MyMem12Cpy(ptr, oldPtr, newNU);
270 InsertNode(p, oldPtr, i0);
271 return ptr;
272 }
273 SplitBlock(p, oldPtr, i0, i1);
274 return oldPtr;
275 }
276
277 #define SUCCESSOR(p) ((CPpmd_Void_Ref)((p)->SuccessorLow | ((UInt32)(p)->SuccessorHigh << 16)))
278
SetSuccessor(CPpmd_State * p,CPpmd_Void_Ref v)279 static void SetSuccessor(CPpmd_State *p, CPpmd_Void_Ref v)
280 {
281 (p)->SuccessorLow = (UInt16)((UInt32)(v) & 0xFFFF);
282 (p)->SuccessorHigh = (UInt16)(((UInt32)(v) >> 16) & 0xFFFF);
283 }
284
RestartModel(CPpmd7 * p)285 static void RestartModel(CPpmd7 *p)
286 {
287 unsigned i, k, m;
288
289 memset(p->FreeList, 0, sizeof(p->FreeList));
290 p->Text = p->Base + p->AlignOffset;
291 p->HiUnit = p->Text + p->Size;
292 p->LoUnit = p->UnitsStart = p->HiUnit - p->Size / 8 / UNIT_SIZE * 7 * UNIT_SIZE;
293 p->GlueCount = 0;
294
295 p->OrderFall = p->MaxOrder;
296 p->RunLength = p->InitRL = -(Int32)((p->MaxOrder < 12) ? p->MaxOrder : 12) - 1;
297 p->PrevSuccess = 0;
298
299 p->MinContext = p->MaxContext = (CTX_PTR)(p->HiUnit -= UNIT_SIZE); /* AllocContext(p); */
300 p->MinContext->Suffix = 0;
301 p->MinContext->NumStats = 256;
302 p->MinContext->SummFreq = 256 + 1;
303 p->FoundState = (CPpmd_State *)p->LoUnit; /* AllocUnits(p, PPMD_NUM_INDEXES - 1); */
304 p->LoUnit += U2B(256 / 2);
305 p->MinContext->Stats = REF(p->FoundState);
306 for (i = 0; i < 256; i++)
307 {
308 CPpmd_State *s = &p->FoundState[i];
309 s->Symbol = (Byte)i;
310 s->Freq = 1;
311 SetSuccessor(s, 0);
312 }
313
314 for (i = 0; i < 128; i++)
315 for (k = 0; k < 8; k++)
316 {
317 UInt16 *dest = p->BinSumm[i] + k;
318 UInt16 val = (UInt16)(PPMD_BIN_SCALE - kInitBinEsc[k] / (i + 2));
319 for (m = 0; m < 64; m += 8)
320 dest[m] = val;
321 }
322
323 for (i = 0; i < 25; i++)
324 for (k = 0; k < 16; k++)
325 {
326 CPpmd_See *s = &p->See[i][k];
327 s->Summ = (UInt16)((5 * i + 10) << (s->Shift = PPMD_PERIOD_BITS - 4));
328 s->Count = 4;
329 }
330 }
331
Ppmd7_Init(CPpmd7 * p,unsigned maxOrder)332 void Ppmd7_Init(CPpmd7 *p, unsigned maxOrder)
333 {
334 p->MaxOrder = maxOrder;
335 RestartModel(p);
336 p->DummySee.Shift = PPMD_PERIOD_BITS;
337 p->DummySee.Summ = 0; /* unused */
338 p->DummySee.Count = 64; /* unused */
339 }
340
CreateSuccessors(CPpmd7 * p,Bool skip)341 static CTX_PTR CreateSuccessors(CPpmd7 *p, Bool skip)
342 {
343 CPpmd_State upState;
344 CTX_PTR c = p->MinContext;
345 CPpmd_Byte_Ref upBranch = (CPpmd_Byte_Ref)SUCCESSOR(p->FoundState);
346 CPpmd_State *ps[PPMD7_MAX_ORDER];
347 unsigned numPs = 0;
348
349 if (!skip)
350 ps[numPs++] = p->FoundState;
351
352 while (c->Suffix)
353 {
354 CPpmd_Void_Ref successor;
355 CPpmd_State *s;
356 c = SUFFIX(c);
357 if (c->NumStats != 1)
358 {
359 for (s = STATS(c); s->Symbol != p->FoundState->Symbol; s++);
360 }
361 else
362 s = ONE_STATE(c);
363 successor = SUCCESSOR(s);
364 if (successor != upBranch)
365 {
366 c = CTX(successor);
367 if (numPs == 0)
368 return c;
369 break;
370 }
371 ps[numPs++] = s;
372 }
373
374 upState.Symbol = *(const Byte *)Ppmd7_GetPtr(p, upBranch);
375 SetSuccessor(&upState, upBranch + 1);
376
377 if (c->NumStats == 1)
378 upState.Freq = ONE_STATE(c)->Freq;
379 else
380 {
381 UInt32 cf, s0;
382 CPpmd_State *s;
383 for (s = STATS(c); s->Symbol != upState.Symbol; s++);
384 cf = s->Freq - 1;
385 s0 = c->SummFreq - c->NumStats - cf;
386 upState.Freq = (Byte)(1 + ((2 * cf <= s0) ? (5 * cf > s0) : ((2 * cf + 3 * s0 - 1) / (2 * s0))));
387 }
388
389 do
390 {
391 /* Create Child */
392 CTX_PTR c1; /* = AllocContext(p); */
393 if (p->HiUnit != p->LoUnit)
394 c1 = (CTX_PTR)(p->HiUnit -= UNIT_SIZE);
395 else if (p->FreeList[0] != 0)
396 c1 = (CTX_PTR)RemoveNode(p, 0);
397 else
398 {
399 c1 = (CTX_PTR)AllocUnitsRare(p, 0);
400 if (!c1)
401 return NULL;
402 }
403 c1->NumStats = 1;
404 *ONE_STATE(c1) = upState;
405 c1->Suffix = REF(c);
406 SetSuccessor(ps[--numPs], REF(c1));
407 c = c1;
408 }
409 while (numPs != 0);
410
411 return c;
412 }
413
SwapStates(CPpmd_State * t1,CPpmd_State * t2)414 static void SwapStates(CPpmd_State *t1, CPpmd_State *t2)
415 {
416 CPpmd_State tmp = *t1;
417 *t1 = *t2;
418 *t2 = tmp;
419 }
420
UpdateModel(CPpmd7 * p)421 static void UpdateModel(CPpmd7 *p)
422 {
423 CPpmd_Void_Ref successor, fSuccessor = SUCCESSOR(p->FoundState);
424 CTX_PTR c;
425 unsigned s0, ns;
426
427 if (p->FoundState->Freq < MAX_FREQ / 4 && p->MinContext->Suffix != 0)
428 {
429 c = SUFFIX(p->MinContext);
430
431 if (c->NumStats == 1)
432 {
433 CPpmd_State *s = ONE_STATE(c);
434 if (s->Freq < 32)
435 s->Freq++;
436 }
437 else
438 {
439 CPpmd_State *s = STATS(c);
440 if (s->Symbol != p->FoundState->Symbol)
441 {
442 do { s++; } while (s->Symbol != p->FoundState->Symbol);
443 if (s[0].Freq >= s[-1].Freq)
444 {
445 SwapStates(&s[0], &s[-1]);
446 s--;
447 }
448 }
449 if (s->Freq < MAX_FREQ - 9)
450 {
451 s->Freq += 2;
452 c->SummFreq += 2;
453 }
454 }
455 }
456
457 if (p->OrderFall == 0)
458 {
459 p->MinContext = p->MaxContext = CreateSuccessors(p, True);
460 if (p->MinContext == 0)
461 {
462 RestartModel(p);
463 return;
464 }
465 SetSuccessor(p->FoundState, REF(p->MinContext));
466 return;
467 }
468
469 *p->Text++ = p->FoundState->Symbol;
470 successor = REF(p->Text);
471 if (p->Text >= p->UnitsStart)
472 {
473 RestartModel(p);
474 return;
475 }
476
477 if (fSuccessor)
478 {
479 if (fSuccessor <= successor)
480 {
481 CTX_PTR cs = CreateSuccessors(p, False);
482 if (cs == NULL)
483 {
484 RestartModel(p);
485 return;
486 }
487 fSuccessor = REF(cs);
488 }
489 if (--p->OrderFall == 0)
490 {
491 successor = fSuccessor;
492 p->Text -= (p->MaxContext != p->MinContext);
493 }
494 }
495 else
496 {
497 SetSuccessor(p->FoundState, successor);
498 fSuccessor = REF(p->MinContext);
499 }
500
501 s0 = p->MinContext->SummFreq - (ns = p->MinContext->NumStats) - (p->FoundState->Freq - 1);
502
503 for (c = p->MaxContext; c != p->MinContext; c = SUFFIX(c))
504 {
505 unsigned ns1;
506 UInt32 cf, sf;
507 if ((ns1 = c->NumStats) != 1)
508 {
509 if ((ns1 & 1) == 0)
510 {
511 /* Expand for one UNIT */
512 unsigned oldNU = ns1 >> 1;
513 unsigned i = U2I(oldNU);
514 if (i != U2I(oldNU + 1))
515 {
516 void *ptr = AllocUnits(p, i + 1);
517 void *oldPtr;
518 if (!ptr)
519 {
520 RestartModel(p);
521 return;
522 }
523 oldPtr = STATS(c);
524 MyMem12Cpy(ptr, oldPtr, oldNU);
525 InsertNode(p, oldPtr, i);
526 c->Stats = STATS_REF(ptr);
527 }
528 }
529 c->SummFreq = (UInt16)(c->SummFreq + (2 * ns1 < ns) + 2 * ((4 * ns1 <= ns) & (c->SummFreq <= 8 * ns1)));
530 }
531 else
532 {
533 CPpmd_State *s = (CPpmd_State*)AllocUnits(p, 0);
534 if (!s)
535 {
536 RestartModel(p);
537 return;
538 }
539 *s = *ONE_STATE(c);
540 c->Stats = REF(s);
541 if (s->Freq < MAX_FREQ / 4 - 1)
542 s->Freq <<= 1;
543 else
544 s->Freq = MAX_FREQ - 4;
545 c->SummFreq = (UInt16)(s->Freq + p->InitEsc + (ns > 3));
546 }
547 cf = 2 * (UInt32)p->FoundState->Freq * (c->SummFreq + 6);
548 sf = (UInt32)s0 + c->SummFreq;
549 if (cf < 6 * sf)
550 {
551 cf = 1 + (cf > sf) + (cf >= 4 * sf);
552 c->SummFreq += 3;
553 }
554 else
555 {
556 cf = 4 + (cf >= 9 * sf) + (cf >= 12 * sf) + (cf >= 15 * sf);
557 c->SummFreq = (UInt16)(c->SummFreq + cf);
558 }
559 {
560 CPpmd_State *s = STATS(c) + ns1;
561 SetSuccessor(s, successor);
562 s->Symbol = p->FoundState->Symbol;
563 s->Freq = (Byte)cf;
564 c->NumStats = (UInt16)(ns1 + 1);
565 }
566 }
567 p->MaxContext = p->MinContext = CTX(fSuccessor);
568 }
569
Rescale(CPpmd7 * p)570 static void Rescale(CPpmd7 *p)
571 {
572 unsigned i, adder, sumFreq, escFreq;
573 CPpmd_State *stats = STATS(p->MinContext);
574 CPpmd_State *s = p->FoundState;
575 {
576 CPpmd_State tmp = *s;
577 for (; s != stats; s--)
578 s[0] = s[-1];
579 *s = tmp;
580 }
581 escFreq = p->MinContext->SummFreq - s->Freq;
582 s->Freq += 4;
583 adder = (p->OrderFall != 0);
584 s->Freq = (Byte)((s->Freq + adder) >> 1);
585 sumFreq = s->Freq;
586
587 i = p->MinContext->NumStats - 1;
588 do
589 {
590 escFreq -= (++s)->Freq;
591 s->Freq = (Byte)((s->Freq + adder) >> 1);
592 sumFreq += s->Freq;
593 if (s[0].Freq > s[-1].Freq)
594 {
595 CPpmd_State *s1 = s;
596 CPpmd_State tmp = *s1;
597 do
598 s1[0] = s1[-1];
599 while (--s1 != stats && tmp.Freq > s1[-1].Freq);
600 *s1 = tmp;
601 }
602 }
603 while (--i);
604
605 if (s->Freq == 0)
606 {
607 unsigned numStats = p->MinContext->NumStats;
608 unsigned n0, n1;
609 do { i++; } while ((--s)->Freq == 0);
610 escFreq += i;
611 p->MinContext->NumStats = (UInt16)(p->MinContext->NumStats - i);
612 if (p->MinContext->NumStats == 1)
613 {
614 CPpmd_State tmp = *stats;
615 do
616 {
617 tmp.Freq = (Byte)(tmp.Freq - (tmp.Freq >> 1));
618 escFreq >>= 1;
619 }
620 while (escFreq > 1);
621 InsertNode(p, stats, U2I(((numStats + 1) >> 1)));
622 *(p->FoundState = ONE_STATE(p->MinContext)) = tmp;
623 return;
624 }
625 n0 = (numStats + 1) >> 1;
626 n1 = (p->MinContext->NumStats + 1) >> 1;
627 if (n0 != n1)
628 p->MinContext->Stats = STATS_REF(ShrinkUnits(p, stats, n0, n1));
629 }
630 p->MinContext->SummFreq = (UInt16)(sumFreq + escFreq - (escFreq >> 1));
631 p->FoundState = STATS(p->MinContext);
632 }
633
Ppmd7_MakeEscFreq(CPpmd7 * p,unsigned numMasked,UInt32 * escFreq)634 CPpmd_See *Ppmd7_MakeEscFreq(CPpmd7 *p, unsigned numMasked, UInt32 *escFreq)
635 {
636 CPpmd_See *see;
637 unsigned nonMasked = p->MinContext->NumStats - numMasked;
638 if (p->MinContext->NumStats != 256)
639 {
640 see = p->See[p->NS2Indx[nonMasked - 1]] +
641 (nonMasked < (unsigned)SUFFIX(p->MinContext)->NumStats - p->MinContext->NumStats) +
642 2 * (p->MinContext->SummFreq < 11 * p->MinContext->NumStats) +
643 4 * (numMasked > nonMasked) +
644 p->HiBitsFlag;
645 {
646 unsigned r = (see->Summ >> see->Shift);
647 see->Summ = (UInt16)(see->Summ - r);
648 *escFreq = r + (r == 0);
649 }
650 }
651 else
652 {
653 see = &p->DummySee;
654 *escFreq = 1;
655 }
656 return see;
657 }
658
NextContext(CPpmd7 * p)659 static void NextContext(CPpmd7 *p)
660 {
661 CTX_PTR c = CTX(SUCCESSOR(p->FoundState));
662 if (p->OrderFall == 0 && (Byte *)c > p->Text)
663 p->MinContext = p->MaxContext = c;
664 else
665 UpdateModel(p);
666 }
667
Ppmd7_Update1(CPpmd7 * p)668 void Ppmd7_Update1(CPpmd7 *p)
669 {
670 CPpmd_State *s = p->FoundState;
671 s->Freq += 4;
672 p->MinContext->SummFreq += 4;
673 if (s[0].Freq > s[-1].Freq)
674 {
675 SwapStates(&s[0], &s[-1]);
676 p->FoundState = --s;
677 if (s->Freq > MAX_FREQ)
678 Rescale(p);
679 }
680 NextContext(p);
681 }
682
Ppmd7_Update1_0(CPpmd7 * p)683 void Ppmd7_Update1_0(CPpmd7 *p)
684 {
685 p->PrevSuccess = (2 * p->FoundState->Freq > p->MinContext->SummFreq);
686 p->RunLength += p->PrevSuccess;
687 p->MinContext->SummFreq += 4;
688 if ((p->FoundState->Freq += 4) > MAX_FREQ)
689 Rescale(p);
690 NextContext(p);
691 }
692
Ppmd7_UpdateBin(CPpmd7 * p)693 void Ppmd7_UpdateBin(CPpmd7 *p)
694 {
695 p->FoundState->Freq = (Byte)(p->FoundState->Freq + (p->FoundState->Freq < 128 ? 1: 0));
696 p->PrevSuccess = 1;
697 p->RunLength++;
698 NextContext(p);
699 }
700
Ppmd7_Update2(CPpmd7 * p)701 void Ppmd7_Update2(CPpmd7 *p)
702 {
703 p->MinContext->SummFreq += 4;
704 if ((p->FoundState->Freq += 4) > MAX_FREQ)
705 Rescale(p);
706 p->RunLength = p->InitRL;
707 UpdateModel(p);
708 }
709