1/* Ppmd7.c -- PPMdH codec
22010-03-12 : Igor Pavlov : Public domain
3This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
4
5#include <memory.h>
6
7#include "Ppmd7.h"
8
9const Byte PPMD7_kExpEscape[16] = { 25, 14, 9, 7, 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 2, 2 };
10static 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
32typedef CPpmd7_Context * CTX_PTR;
33
34struct CPpmd7_Node_;
35
36typedef
37  #ifdef PPMD_32BIT
38    struct CPpmd7_Node_ *
39  #else
40    UInt32
41  #endif
42  CPpmd7_Node_Ref;
43
44typedef 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
58void 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
89void Ppmd7_Free(CPpmd7 *p, ISzAlloc *alloc)
90{
91  alloc->Free(alloc, p->Base);
92  p->Size = 0;
93  p->Base = 0;
94}
95
96Bool 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
118static 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
124static 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
131static 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
143static 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
215static 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
241static 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
260static 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
279static 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
285static 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
332void 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
341static 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
414static void SwapStates(CPpmd_State *t1, CPpmd_State *t2)
415{
416  CPpmd_State tmp = *t1;
417  *t1 = *t2;
418  *t2 = tmp;
419}
420
421static 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
570static 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
634CPpmd_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
659static 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
668void 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
683void 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
693void 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
701void 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