File indexing completed on 2025-02-02 04:25:59

 /* Ppmd7.c -- PPMdH codec
 2010-03-12 : Igor Pavlov : Public domain
 This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */
 
 #include "Precomp.h"
 
 #include <memory.h>
 
 #include "Ppmd7.h"
 
 const Byte PPMD7_kExpEscape[16] = { 25, 14, 9, 7, 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 2, 2 };
 static const UInt16 kInitBinEsc[] = { 0x3CDD, 0x1F3F, 0x59BF, 0x48F3, 0x64A1, 0x5ABC, 0x6632, 0x6051};
 
 #define MAX_FREQ 124
 #define UNIT_SIZE 12
 
 #define U2B(nu) ((UInt32)(nu) * UNIT_SIZE)
 #define U2I(nu) (p->Units2Indx[(nu) - 1])
 #define I2U(indx) (p->Indx2Units[indx])
 
 #ifdef PPMD_32BIT
   #define REF(ptr) (ptr)
 #else
   #define REF(ptr) ((UInt32)((Byte *)(ptr) - (p)->Base))
 #endif
 
 #define STATS_REF(ptr) ((CPpmd_State_Ref)REF(ptr))
 
 #define CTX(ref) ((CPpmd7_Context *)Ppmd7_GetContext(p, ref))
 #define STATS(ctx) Ppmd7_GetStats(p, ctx)
 #define ONE_STATE(ctx) Ppmd7Context_OneState(ctx)
 #define SUFFIX(ctx) CTX((ctx)->Suffix)
 
 typedef CPpmd7_Context * CTX_PTR;
 
 struct CPpmd7_Node_;
 
 typedef
   #ifdef PPMD_32BIT
     struct CPpmd7_Node_ *
   #else
     UInt32
   #endif
   CPpmd7_Node_Ref;
 
 typedef struct CPpmd7_Node_
 {
   UInt16 Stamp; /* must be at offset 0 as CPpmd7_Context::NumStats. Stamp=0 means free */
   UInt16 NU;
   CPpmd7_Node_Ref Next; /* must be at offset >= 4 */
   CPpmd7_Node_Ref Prev;
 } CPpmd7_Node;
 
 #ifdef PPMD_32BIT
   #define NODE(ptr) (ptr)
 #else
   #define NODE(offs) ((CPpmd7_Node *)(p->Base + (offs)))
 #endif
 
 void Ppmd7_Construct(CPpmd7 *p)
 {
   unsigned i, k, m;
 
   p->Base = 0;
 
   for (i = 0, k = 0; i < PPMD_NUM_INDEXES; i++)
   {
     unsigned step = (i >= 12 ? 4 : (i >> 2) + 1);
     do { p->Units2Indx[k++] = (Byte)i; } while(--step);
     p->Indx2Units[i] = (Byte)k;
   }
 
   p->NS2BSIndx[0] = (0 << 1);
   p->NS2BSIndx[1] = (1 << 1);
   memset(p->NS2BSIndx + 2, (2 << 1), 9);
   memset(p->NS2BSIndx + 11, (3 << 1), 256 - 11);
 
   for (i = 0; i < 3; i++)
     p->NS2Indx[i] = (Byte)i;
   for (m = i, k = 1; i < 256; i++)
   {
     p->NS2Indx[i] = (Byte)m;
     if (--k == 0)
       k = (++m) - 2;
   }
 
   memset(p->HB2Flag, 0, 0x40);
   memset(p->HB2Flag + 0x40, 8, 0x100 - 0x40);
 }
 
 void Ppmd7_Free(CPpmd7 *p, ISzAlloc *alloc)
 {
   alloc->Free(alloc, p->Base);
   p->Size = 0;
   p->Base = 0;
 }
 
 Bool Ppmd7_Alloc(CPpmd7 *p, UInt32 size, ISzAlloc *alloc)
 {
   if (p->Base == 0 || p->Size != size)
   {
     Ppmd7_Free(p, alloc);
     p->AlignOffset =
       #ifdef PPMD_32BIT
         (4 - size) & 3;
       #else
         4 - (size & 3);
       #endif
     if ((p->Base = (Byte *)alloc->Alloc(alloc, p->AlignOffset + size
         #ifndef PPMD_32BIT
         + UNIT_SIZE
         #endif
         )) == 0)
       return False;
     p->Size = size;
   }
   return True;
 }
 
 static void InsertNode(CPpmd7 *p, void *node, unsigned indx)
 {
   *((CPpmd_Void_Ref *)node) = p->FreeList[indx];
   p->FreeList[indx] = REF(node);
 }
 
 static void *RemoveNode(CPpmd7 *p, unsigned indx)
 {
   CPpmd_Void_Ref *node = (CPpmd_Void_Ref *)Ppmd7_GetPtr(p, p->FreeList[indx]);
   p->FreeList[indx] = *node;
   return node;
 }
 
 static void SplitBlock(CPpmd7 *p, void *ptr, unsigned oldIndx, unsigned newIndx)
 {
   unsigned i, nu = I2U(oldIndx) - I2U(newIndx);
   ptr = (Byte *)ptr + U2B(I2U(newIndx));
   if (I2U(i = U2I(nu)) != nu)
   {
     unsigned k = I2U(--i);
     InsertNode(p, ((Byte *)ptr) + U2B(k), nu - k - 1);
   }
   InsertNode(p, ptr, i);
 }
 
 static void GlueFreeBlocks(CPpmd7 *p)
 {
   #ifdef PPMD_32BIT
   CPpmd7_Node headItem;
   CPpmd7_Node_Ref head = &headItem;
   #else
   CPpmd7_Node_Ref head = p->AlignOffset + p->Size;
   #endif
   
   CPpmd7_Node_Ref n = head;
   unsigned i;
 
   p->GlueCount = 255;
 
   /* create doubly-linked list of free blocks */
   for (i = 0; i < PPMD_NUM_INDEXES; i++)
   {
     UInt16 nu = I2U(i);
     CPpmd7_Node_Ref next = (CPpmd7_Node_Ref)p->FreeList[i];
     p->FreeList[i] = 0;
     while (next != 0)
     {
       CPpmd7_Node *node = NODE(next);
       node->Next = n;
       n = NODE(n)->Prev = next;
       next = *(const CPpmd7_Node_Ref *)node;
       node->Stamp = 0;
       node->NU = (UInt16)nu;
     }
   }
   NODE(head)->Stamp = 1;
   NODE(head)->Next = n;
   NODE(n)->Prev = head;
   if (p->LoUnit != p->HiUnit)
     ((CPpmd7_Node *)p->LoUnit)->Stamp = 1;
   
   /* Glue free blocks */
   while (n != head)
   {
     CPpmd7_Node *node = NODE(n);
     UInt32 nu = (UInt32)node->NU;
     for (;;)
     {
       CPpmd7_Node *node2 = NODE(n) + nu;
       nu += node2->NU;
       if (node2->Stamp != 0 || nu >= 0x10000)
         break;
       NODE(node2->Prev)->Next = node2->Next;
       NODE(node2->Next)->Prev = node2->Prev;
       node->NU = (UInt16)nu;
     }
     n = node->Next;
   }
   
   /* Fill lists of free blocks */
   for (n = NODE(head)->Next; n != head;)
   {
     CPpmd7_Node *node = NODE(n);
     unsigned nu;
     CPpmd7_Node_Ref next = node->Next;
     for (nu = node->NU; nu > 128; nu -= 128, node += 128)
       InsertNode(p, node, PPMD_NUM_INDEXES - 1);
     if (I2U(i = U2I(nu)) != nu)
     {
       unsigned k = I2U(--i);
       InsertNode(p, node + k, nu - k - 1);
     }
     InsertNode(p, node, i);
     n = next;
   }
 }
 
 static void *AllocUnitsRare(CPpmd7 *p, unsigned indx)
 {
   unsigned i;
   void *retVal;
   if (p->GlueCount == 0)
   {
     GlueFreeBlocks(p);
     if (p->FreeList[indx] != 0)
       return RemoveNode(p, indx);
   }
   i = indx;
   do
   {
     if (++i == PPMD_NUM_INDEXES)
     {
       UInt32 numBytes = U2B(I2U(indx));
       p->GlueCount--;
       return ((UInt32)(p->UnitsStart - p->Text) > numBytes) ? (p->UnitsStart -= numBytes) : (NULL);
     }
   }
   while (p->FreeList[i] == 0);
   retVal = RemoveNode(p, i);
   SplitBlock(p, retVal, i, indx);
   return retVal;
 }
 
 static void *AllocUnits(CPpmd7 *p, unsigned indx)
 {
   UInt32 numBytes;
   if (p->FreeList[indx] != 0)
     return RemoveNode(p, indx);
   numBytes = U2B(I2U(indx));
   if (numBytes <= (UInt32)(p->HiUnit - p->LoUnit))
   {
     void *retVal = p->LoUnit;
     p->LoUnit += numBytes;
     return retVal;
   }
   return AllocUnitsRare(p, indx);
 }
 
 #define MyMem12Cpy(dest, src, num) \
   { UInt32 *d = (UInt32 *)dest; const UInt32 *s = (const UInt32 *)src; UInt32 n = num; \
     do { d[0] = s[0]; d[1] = s[1]; d[2] = s[2]; s += 3; d += 3; } while(--n); }
 
 static void *ShrinkUnits(CPpmd7 *p, void *oldPtr, unsigned oldNU, unsigned newNU)
 {
   unsigned i0 = U2I(oldNU);
   unsigned i1 = U2I(newNU);
   if (i0 == i1)
     return oldPtr;
   if (p->FreeList[i1] != 0)
   {
     void *ptr = RemoveNode(p, i1);
     MyMem12Cpy(ptr, oldPtr, newNU);
     InsertNode(p, oldPtr, i0);
     return ptr;
   }
   SplitBlock(p, oldPtr, i0, i1);
   return oldPtr;
 }
 
 #define SUCCESSOR(p) ((CPpmd_Void_Ref)((p)->SuccessorLow | ((UInt32)(p)->SuccessorHigh << 16)))
 
 static void SetSuccessor(CPpmd_State *p, CPpmd_Void_Ref v)
 {
   (p)->SuccessorLow = (UInt16)((UInt32)(v) & 0xFFFF);
   (p)->SuccessorHigh = (UInt16)(((UInt32)(v) >> 16) & 0xFFFF);
 }
 
 static void RestartModel(CPpmd7 *p)
 {
   unsigned i, k, m;
 
   memset(p->FreeList, 0, sizeof(p->FreeList));
   p->Text = p->Base + p->AlignOffset;
   p->HiUnit = p->Text + p->Size;
   p->LoUnit = p->UnitsStart = p->HiUnit - p->Size / 8 / UNIT_SIZE * 7 * UNIT_SIZE;
   p->GlueCount = 0;
 
   p->OrderFall = p->MaxOrder;
   p->RunLength = p->InitRL = -(Int32)((p->MaxOrder < 12) ? p->MaxOrder : 12) - 1;
   p->PrevSuccess = 0;
 
   p->MinContext = p->MaxContext = (CTX_PTR)(p->HiUnit -= UNIT_SIZE); /* AllocContext(p); */
   p->MinContext->Suffix = 0;
   p->MinContext->NumStats = 256;
   p->MinContext->SummFreq = 256 + 1;
   p->FoundState = (CPpmd_State *)p->LoUnit; /* AllocUnits(p, PPMD_NUM_INDEXES - 1); */
   p->LoUnit += U2B(256 / 2);
   p->MinContext->Stats = REF(p->FoundState);
   for (i = 0; i < 256; i++)
   {
     CPpmd_State *s = &p->FoundState[i];
     s->Symbol = (Byte)i;
     s->Freq = 1;
     SetSuccessor(s, 0);
   }
 
   for (i = 0; i < 128; i++)
     for (k = 0; k < 8; k++)
     {
       UInt16 *dest = p->BinSumm[i] + k;
       UInt16 val = (UInt16)(PPMD_BIN_SCALE - kInitBinEsc[k] / (i + 2));
       for (m = 0; m < 64; m += 8)
         dest[m] = val;
     }
   
   for (i = 0; i < 25; i++)
     for (k = 0; k < 16; k++)
     {
       CPpmd_See *s = &p->See[i][k];
       s->Summ = (UInt16)((5 * i + 10) << (s->Shift = PPMD_PERIOD_BITS - 4));
       s->Count = 4;
     }
 }
 
 void Ppmd7_Init(CPpmd7 *p, unsigned maxOrder)
 {
   p->MaxOrder = maxOrder;
   RestartModel(p);
   p->DummySee.Shift = PPMD_PERIOD_BITS;
   p->DummySee.Summ = 0; /* unused */
   p->DummySee.Count = 64; /* unused */
 }
 
 static CTX_PTR CreateSuccessors(CPpmd7 *p, Bool skip)
 {
   CPpmd_State upState;
   CTX_PTR c = p->MinContext;
   CPpmd_Byte_Ref upBranch = (CPpmd_Byte_Ref)SUCCESSOR(p->FoundState);
   CPpmd_State *ps[PPMD7_MAX_ORDER];
   unsigned numPs = 0;
   
   if (!skip)
     ps[numPs++] = p->FoundState;
   
   while (c->Suffix)
   {
     CPpmd_Void_Ref successor;
     CPpmd_State *s;
     c = SUFFIX(c);
     if (c->NumStats != 1)
     {
       for (s = STATS(c); s->Symbol != p->FoundState->Symbol; s++);
     }
     else
       s = ONE_STATE(c);
     successor = SUCCESSOR(s);
     if (successor != upBranch)
     {
       c = CTX(successor);
       if (numPs == 0)
         return c;
       break;
     }
     ps[numPs++] = s;
   }
   
   upState.Symbol = *(const Byte *)Ppmd7_GetPtr(p, upBranch);
   SetSuccessor(&upState, upBranch + 1);
   
   if (c->NumStats == 1)
     upState.Freq = ONE_STATE(c)->Freq;
   else
   {
     UInt32 cf, s0;
     CPpmd_State *s;
     for (s = STATS(c); s->Symbol != upState.Symbol; s++);
     cf = s->Freq - 1;
     s0 = c->SummFreq - c->NumStats - cf;
     upState.Freq = (Byte)(1 + ((2 * cf <= s0) ? (5 * cf > s0) : ((2 * cf + 3 * s0 - 1) / (2 * s0))));
   }
 
   do
   {
     /* Create Child */
     CTX_PTR c1; /* = AllocContext(p); */
     if (p->HiUnit != p->LoUnit)
       c1 = (CTX_PTR)(p->HiUnit -= UNIT_SIZE);
     else if (p->FreeList[0] != 0)
       c1 = (CTX_PTR)RemoveNode(p, 0);
     else
     {
       c1 = (CTX_PTR)AllocUnitsRare(p, 0);
       if (!c1)
         return NULL;
     }
     c1->NumStats = 1;
     *ONE_STATE(c1) = upState;
     c1->Suffix = REF(c);
     SetSuccessor(ps[--numPs], REF(c1));
     c = c1;
   }
   while (numPs != 0);
   
   return c;
 }
 
 static void SwapStates(CPpmd_State *t1, CPpmd_State *t2)
 {
   CPpmd_State tmp = *t1;
   *t1 = *t2;
   *t2 = tmp;
 }
 
 static void UpdateModel(CPpmd7 *p)
 {
   CPpmd_Void_Ref successor, fSuccessor = SUCCESSOR(p->FoundState);
   CTX_PTR c;
   unsigned s0, ns;
   
   if (p->FoundState->Freq < MAX_FREQ / 4 && p->MinContext->Suffix != 0)
   {
     c = SUFFIX(p->MinContext);
     
     if (c->NumStats == 1)
     {
       CPpmd_State *s = ONE_STATE(c);
       if (s->Freq < 32)
         s->Freq++;
     }
     else
     {
       CPpmd_State *s = STATS(c);
       if (s->Symbol != p->FoundState->Symbol)
       {
         do { s++; } while (s->Symbol != p->FoundState->Symbol);
         if (s[0].Freq >= s[-1].Freq)
         {
           SwapStates(&s[0], &s[-1]);
           s--;
         }
       }
       if (s->Freq < MAX_FREQ - 9)
       {
         s->Freq += 2;
         c->SummFreq += 2;
       }
     }
   }
 
   if (p->OrderFall == 0)
   {
     p->MinContext = p->MaxContext = CreateSuccessors(p, True);
     if (p->MinContext == 0)
     {
       RestartModel(p);
       return;
     }
     SetSuccessor(p->FoundState, REF(p->MinContext));
     return;
   }
   
   *p->Text++ = p->FoundState->Symbol;
   successor = REF(p->Text);
   if (p->Text >= p->UnitsStart)
   {
     RestartModel(p);
     return;
   }
   
   if (fSuccessor)
   {
     if (fSuccessor <= successor)
     {
       CTX_PTR cs = CreateSuccessors(p, False);
       if (cs == NULL)
       {
         RestartModel(p);
         return;
       }
       fSuccessor = REF(cs);
     }
     if (--p->OrderFall == 0)
     {
       successor = fSuccessor;
       p->Text -= (p->MaxContext != p->MinContext);
     }
   }
   else
   {
     SetSuccessor(p->FoundState, successor);
     fSuccessor = REF(p->MinContext);
   }
   
   s0 = p->MinContext->SummFreq - (ns = p->MinContext->NumStats) - (p->FoundState->Freq - 1);
   
   for (c = p->MaxContext; c != p->MinContext; c = SUFFIX(c))
   {
     unsigned ns1;
     UInt32 cf, sf;
     if ((ns1 = c->NumStats) != 1)
     {
       if ((ns1 & 1) == 0)
       {
         /* Expand for one UNIT */
         unsigned oldNU = ns1 >> 1;
         unsigned i = U2I(oldNU);
         if (i != U2I(oldNU + 1))
         {
           void *ptr = AllocUnits(p, i + 1);
           void *oldPtr;
           if (!ptr)
           {
             RestartModel(p);
             return;
           }
           oldPtr = STATS(c);
           MyMem12Cpy(ptr, oldPtr, oldNU);
           InsertNode(p, oldPtr, i);
           c->Stats = STATS_REF(ptr);
         }
       }
       c->SummFreq = (UInt16)(c->SummFreq + (2 * ns1 < ns) + 2 * ((4 * ns1 <= ns) & (c->SummFreq <= 8 * ns1)));
     }
     else
     {
       CPpmd_State *s = (CPpmd_State*)AllocUnits(p, 0);
       if (!s)
       {
         RestartModel(p);
         return;
       }
       *s = *ONE_STATE(c);
       c->Stats = REF(s);
       if (s->Freq < MAX_FREQ / 4 - 1)
         s->Freq <<= 1;
       else
         s->Freq = MAX_FREQ - 4;
       c->SummFreq = (UInt16)(s->Freq + p->InitEsc + (ns > 3));
     }
     cf = 2 * (UInt32)p->FoundState->Freq * (c->SummFreq + 6);
     sf = (UInt32)s0 + c->SummFreq;
     if (cf < 6 * sf)
     {
       cf = 1 + (cf > sf) + (cf >= 4 * sf);
       c->SummFreq += 3;
     }
     else
     {
       cf = 4 + (cf >= 9 * sf) + (cf >= 12 * sf) + (cf >= 15 * sf);
       c->SummFreq = (UInt16)(c->SummFreq + cf);
     }
     {
       CPpmd_State *s = STATS(c) + ns1;
       SetSuccessor(s, successor);
       s->Symbol = p->FoundState->Symbol;
       s->Freq = (Byte)cf;
       c->NumStats = (UInt16)(ns1 + 1);
     }
   }
   p->MaxContext = p->MinContext = CTX(fSuccessor);
 }
   
 static void Rescale(CPpmd7 *p)
 {
   unsigned i, adder, sumFreq, escFreq;
   CPpmd_State *stats = STATS(p->MinContext);
   CPpmd_State *s = p->FoundState;
   {
     CPpmd_State tmp = *s;
     for (; s != stats; s--)
       s[0] = s[-1];
     *s = tmp;
   }
   escFreq = p->MinContext->SummFreq - s->Freq;
   s->Freq += 4;
   adder = (p->OrderFall != 0);
   s->Freq = (Byte)((s->Freq + adder) >> 1);
   sumFreq = s->Freq;
   
   i = p->MinContext->NumStats - 1;
   do
   {
     escFreq -= (++s)->Freq;
     s->Freq = (Byte)((s->Freq + adder) >> 1);
     sumFreq += s->Freq;
     if (s[0].Freq > s[-1].Freq)
     {
       CPpmd_State *s1 = s;
       CPpmd_State tmp = *s1;
       do
         s1[0] = s1[-1];
       while (--s1 != stats && tmp.Freq > s1[-1].Freq);
       *s1 = tmp;
     }
   }
   while (--i);
   
   if (s->Freq == 0)
   {
     unsigned numStats = p->MinContext->NumStats;
     unsigned n0, n1;
     do { i++; } while ((--s)->Freq == 0);
     escFreq += i;
     p->MinContext->NumStats = (UInt16)(p->MinContext->NumStats - i);
     if (p->MinContext->NumStats == 1)
     {
       CPpmd_State tmp = *stats;
       do
       {
         tmp.Freq = (Byte)(tmp.Freq - (tmp.Freq >> 1));
         escFreq >>= 1;
       }
       while (escFreq > 1);
       InsertNode(p, stats, U2I(((numStats + 1) >> 1)));
       *(p->FoundState = ONE_STATE(p->MinContext)) = tmp;
       return;
     }
     n0 = (numStats + 1) >> 1;
     n1 = (p->MinContext->NumStats + 1) >> 1;
     if (n0 != n1)
       p->MinContext->Stats = STATS_REF(ShrinkUnits(p, stats, n0, n1));
   }
   p->MinContext->SummFreq = (UInt16)(sumFreq + escFreq - (escFreq >> 1));
   p->FoundState = STATS(p->MinContext);
 }
 
 CPpmd_See *Ppmd7_MakeEscFreq(CPpmd7 *p, unsigned numMasked, UInt32 *escFreq)
 {
   CPpmd_See *see;
   unsigned nonMasked = p->MinContext->NumStats - numMasked;
   if (p->MinContext->NumStats != 256)
   {
     see = p->See[p->NS2Indx[nonMasked - 1]] +
         (nonMasked < (unsigned)SUFFIX(p->MinContext)->NumStats - p->MinContext->NumStats) +
         2 * (p->MinContext->SummFreq < 11 * p->MinContext->NumStats) +
         4 * (numMasked > nonMasked) +
         p->HiBitsFlag;
     {
       unsigned r = (see->Summ >> see->Shift);
       see->Summ = (UInt16)(see->Summ - r);
       *escFreq = r + (r == 0);
     }
   }
   else
   {
     see = &p->DummySee;
     *escFreq = 1;
   }
   return see;
 }
 
 static void NextContext(CPpmd7 *p)
 {
   CTX_PTR c = CTX(SUCCESSOR(p->FoundState));
   if (p->OrderFall == 0 && (Byte *)c > p->Text)
     p->MinContext = p->MaxContext = c;
   else
     UpdateModel(p);
 }
 
 void Ppmd7_Update1(CPpmd7 *p)
 {
   CPpmd_State *s = p->FoundState;
   s->Freq += 4;
   p->MinContext->SummFreq += 4;
   if (s[0].Freq > s[-1].Freq)
   {
     SwapStates(&s[0], &s[-1]);
     p->FoundState = --s;
     if (s->Freq > MAX_FREQ)
       Rescale(p);
   }
   NextContext(p);
 }
 
 void Ppmd7_Update1_0(CPpmd7 *p)
 {
   p->PrevSuccess = (2 * p->FoundState->Freq > p->MinContext->SummFreq);
   p->RunLength += p->PrevSuccess;
   p->MinContext->SummFreq += 4;
   if ((p->FoundState->Freq += 4) > MAX_FREQ)
     Rescale(p);
   NextContext(p);
 }
 
 void Ppmd7_UpdateBin(CPpmd7 *p)
 {
   p->FoundState->Freq = (Byte)(p->FoundState->Freq + (p->FoundState->Freq < 128 ? 1: 0));
   p->PrevSuccess = 1;
   p->RunLength++;
   NextContext(p);
 }
 
 void Ppmd7_Update2(CPpmd7 *p)
 {
   p->MinContext->SummFreq += 4;
   if ((p->FoundState->Freq += 4) > MAX_FREQ)
     Rescale(p);
   p->RunLength = p->InitRL;
   UpdateModel(p);
 }