From f19f813537c7aea1c20749c914e756b54a9c3cf5 Mon Sep 17 00:00:00 2001 From: Igor Pavlov <87184205+ip7z@users.noreply.github.com> Date: Mon, 27 Dec 2021 00:00:00 +0000 Subject: '21.07' --- C/Ppmd7.c | 1104 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1104 insertions(+) create mode 100644 C/Ppmd7.c (limited to 'C/Ppmd7.c') diff --git a/C/Ppmd7.c b/C/Ppmd7.c new file mode 100644 index 0000000..cf401cb --- /dev/null +++ b/C/Ppmd7.c @@ -0,0 +1,1104 @@ +/* Ppmd7.c -- PPMdH codec +2021-04-13 : Igor Pavlov : Public domain +This code is based on PPMd var.H (2001): Dmitry Shkarin : Public domain */ + +#include "Precomp.h" + +#include + +#include "Ppmd7.h" + +/* define PPMD7_ORDER_0_SUPPPORT to suport order-0 mode, unsupported by orignal PPMd var.H. code */ +// #define PPMD7_ORDER_0_SUPPPORT + +MY_ALIGN(16) +static const Byte PPMD7_kExpEscape[16] = { 25, 14, 9, 7, 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 2, 2 }; +MY_ALIGN(16) +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[(size_t)(nu) - 1]) +#define I2U(indx) ((unsigned)p->Indx2Units[indx]) +#define I2U_UInt16(indx) ((UInt16)p->Indx2Units[indx]) + +#define REF(ptr) Ppmd_GetRef(p, ptr) + +#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 Ppmd_Ref_Type(struct CPpmd7_Node_) 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; + +#define NODE(r) Ppmd_GetPtr_Type(p, r, CPpmd7_Node) + +void Ppmd7_Construct(CPpmd7 *p) +{ + unsigned i, k, m; + + p->Base = NULL; + + 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; + } + + memcpy(p->ExpEscape, PPMD7_kExpEscape, 16); +} + + +void Ppmd7_Free(CPpmd7 *p, ISzAllocPtr alloc) +{ + ISzAlloc_Free(alloc, p->Base); + p->Size = 0; + p->Base = NULL; +} + + +BoolInt Ppmd7_Alloc(CPpmd7 *p, UInt32 size, ISzAllocPtr alloc) +{ + if (!p->Base || p->Size != size) + { + Ppmd7_Free(p, alloc); + p->AlignOffset = (4 - size) & 3; + if ((p->Base = (Byte *)ISzAlloc_Alloc(alloc, p->AlignOffset + size)) == NULL) + return False; + p->Size = size; + } + return True; +} + + + +// ---------- Internal Memory Allocator ---------- + +/* We can use CPpmd7_Node in list of free units (as in Ppmd8) + But we still need one additional list walk pass in GlueFreeBlocks(). + So we use simple CPpmd_Void_Ref instead of CPpmd7_Node in InsertNode() / RemoveNode() +*/ + +#define EMPTY_NODE 0 + + +static void InsertNode(CPpmd7 *p, void *node, unsigned indx) +{ + *((CPpmd_Void_Ref *)node) = p->FreeList[indx]; + // ((CPpmd7_Node *)node)->Next = (CPpmd7_Node_Ref)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; + // CPpmd7_Node *node = NODE((CPpmd7_Node_Ref)p->FreeList[indx]); + // p->FreeList[indx] = node->Next; + 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); +} + + +/* we use CPpmd7_Node_Union union to solve XLC -O2 strict pointer aliasing problem */ + +typedef union _CPpmd7_Node_Union +{ + CPpmd7_Node Node; + CPpmd7_Node_Ref NextRef; +} CPpmd7_Node_Union; + +/* Original PPmdH (Ppmd7) code uses doubly linked list in GlueFreeBlocks() + we use single linked list similar to Ppmd8 code */ + + +static void GlueFreeBlocks(CPpmd7 *p) +{ + /* + we use first UInt16 field of 12-bytes UNITs as record type stamp + CPpmd_State { Byte Symbol; Byte Freq; : Freq != 0 + CPpmd7_Context { UInt16 NumStats; : NumStats != 0 + CPpmd7_Node { UInt16 Stamp : Stamp == 0 for free record + : Stamp == 1 for head record and guard + Last 12-bytes UNIT in array is always contains 12-bytes order-0 CPpmd7_Context record. + */ + CPpmd7_Node_Ref head, n = 0; + + p->GlueCount = 255; + + + /* we set guard NODE at LoUnit */ + if (p->LoUnit != p->HiUnit) + ((CPpmd7_Node *)(void *)p->LoUnit)->Stamp = 1; + + { + /* Create list of free blocks. + We still need one additional list walk pass before Glue. */ + unsigned i; + for (i = 0; i < PPMD_NUM_INDEXES; i++) + { + const UInt16 nu = I2U_UInt16(i); + CPpmd7_Node_Ref next = (CPpmd7_Node_Ref)p->FreeList[i]; + p->FreeList[i] = 0; + while (next != 0) + { + /* Don't change the order of the following commands: */ + CPpmd7_Node_Union *un = (CPpmd7_Node_Union *)NODE(next); + const CPpmd7_Node_Ref tmp = next; + next = un->NextRef; + un->Node.Stamp = EMPTY_NODE; + un->Node.NU = nu; + un->Node.Next = n; + n = tmp; + } + } + } + + head = n; + /* Glue and Fill must walk the list in same direction */ + { + /* Glue free blocks */ + CPpmd7_Node_Ref *prev = &head; + while (n) + { + CPpmd7_Node *node = NODE(n); + UInt32 nu = node->NU; + n = node->Next; + if (nu == 0) + { + *prev = n; + continue; + } + prev = &node->Next; + for (;;) + { + CPpmd7_Node *node2 = node + nu; + nu += node2->NU; + if (node2->Stamp != EMPTY_NODE || nu >= 0x10000) + break; + node->NU = (UInt16)nu; + node2->NU = 0; + } + } + } + + /* Fill lists of free blocks */ + for (n = head; n != 0;) + { + CPpmd7_Node *node = NODE(n); + UInt32 nu = node->NU; + unsigned i; + n = node->Next; + if (nu == 0) + continue; + for (; 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, (unsigned)nu - k - 1); + } + InsertNode(p, node, i); + } +} + + +MY_NO_INLINE +static void *AllocUnitsRare(CPpmd7 *p, unsigned indx) +{ + unsigned i; + + 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)); + Byte *us = p->UnitsStart; + p->GlueCount--; + return ((UInt32)(us - p->Text) > numBytes) ? (p->UnitsStart = us - numBytes) : NULL; + } + } + while (p->FreeList[i] == 0); + + { + void *block = RemoveNode(p, i); + SplitBlock(p, block, i, indx); + return block; + } +} + + +static void *AllocUnits(CPpmd7 *p, unsigned indx) +{ + if (p->FreeList[indx] != 0) + return RemoveNode(p, indx); + { + UInt32 numBytes = U2B(I2U(indx)); + Byte *lo = p->LoUnit; + if ((UInt32)(p->HiUnit - lo) >= numBytes) + { + p->LoUnit = lo + numBytes; + return lo; + } + } + return AllocUnitsRare(p, indx); +} + + +#define MyMem12Cpy(dest, src, num) \ + { UInt32 *d = (UInt32 *)dest; const UInt32 *z = (const UInt32 *)src; UInt32 n = num; \ + do { d[0] = z[0]; d[1] = z[1]; d[2] = z[2]; z += 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) Ppmd_GET_SUCCESSOR(p) +static void SetSuccessor(CPpmd_State *p, CPpmd_Void_Ref v) +{ + Ppmd_SET_SUCCESSOR(p, v); +} + + + +MY_NO_INLINE +static +void RestartModel(CPpmd7 *p) +{ + unsigned i, k; + + 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; + + { + CPpmd7_Context *mc = (CTX_PTR)(void *)(p->HiUnit -= UNIT_SIZE); /* AllocContext(p); */ + CPpmd_State *s = (CPpmd_State *)p->LoUnit; /* AllocUnits(p, PPMD_NUM_INDEXES - 1); */ + + p->LoUnit += U2B(256 / 2); + p->MaxContext = p->MinContext = mc; + p->FoundState = s; + + mc->NumStats = 256; + mc->Union2.SummFreq = 256 + 1; + mc->Union4.Stats = REF(s); + mc->Suffix = 0; + + for (i = 0; i < 256; i++, s++) + { + s->Symbol = (Byte)i; + s->Freq = 1; + SetSuccessor(s, 0); + } + + #ifdef PPMD7_ORDER_0_SUPPPORT + if (p->MaxOrder == 0) + { + CPpmd_Void_Ref r = REF(mc); + s = p->FoundState; + for (i = 0; i < 256; i++, s++) + SetSuccessor(s, r); + return; + } + #endif + } + + for (i = 0; i < 128; i++) + + + + for (k = 0; k < 8; k++) + { + unsigned m; + 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++) + { + + CPpmd_See *s = p->See[i]; + + + + unsigned summ = ((5 * i + 10) << (PPMD_PERIOD_BITS - 4)); + for (k = 0; k < 16; k++, s++) + { + s->Summ = (UInt16)summ; + s->Shift = (PPMD_PERIOD_BITS - 4); + s->Count = 4; + } + } + + p->DummySee.Summ = 0; /* unused */ + p->DummySee.Shift = PPMD_PERIOD_BITS; + p->DummySee.Count = 64; /* unused */ +} + + +void Ppmd7_Init(CPpmd7 *p, unsigned maxOrder) +{ + p->MaxOrder = maxOrder; + + RestartModel(p); +} + + + +/* + CreateSuccessors() + It's called when (FoundState->Successor) is RAW-Successor, + that is the link to position in Raw text. + So we create Context records and write the links to + FoundState->Successor and to identical RAW-Successors in suffix + contexts of MinContex. + + The function returns: + if (OrderFall == 0) then MinContext is already at MAX order, + { return pointer to new or existing context of same MAX order } + else + { return pointer to new real context that will be (Order+1) in comparison with MinContext + + also it can return pointer to real context of same order, +*/ + +MY_NO_INLINE +static CTX_PTR CreateSuccessors(CPpmd7 *p) +{ + CTX_PTR c = p->MinContext; + CPpmd_Byte_Ref upBranch = (CPpmd_Byte_Ref)SUCCESSOR(p->FoundState); + Byte newSym, newFreq; + unsigned numPs = 0; + CPpmd_State *ps[PPMD7_MAX_ORDER]; + + if (p->OrderFall != 0) + ps[numPs++] = p->FoundState; + + while (c->Suffix) + { + CPpmd_Void_Ref successor; + CPpmd_State *s; + c = SUFFIX(c); + + + if (c->NumStats != 1) + { + Byte sym = p->FoundState->Symbol; + for (s = STATS(c); s->Symbol != sym; s++); + + } + else + { + s = ONE_STATE(c); + + } + successor = SUCCESSOR(s); + if (successor != upBranch) + { + // (c) is real record Context here, + c = CTX(successor); + if (numPs == 0) + { + // (c) is real record MAX Order Context here, + // So we don't need to create any new contexts. + return c; + } + break; + } + ps[numPs++] = s; + } + + // All created contexts will have single-symbol with new RAW-Successor + // All new RAW-Successors will point to next position in RAW text + // after FoundState->Successor + + newSym = *(const Byte *)Ppmd7_GetPtr(p, upBranch); + upBranch++; + + + if (c->NumStats == 1) + newFreq = ONE_STATE(c)->Freq; + else + { + UInt32 cf, s0; + CPpmd_State *s; + for (s = STATS(c); s->Symbol != newSym; s++); + cf = (UInt32)s->Freq - 1; + s0 = (UInt32)c->Union2.SummFreq - c->NumStats - cf; + /* + cf - is frequency of symbol that will be Successor in new context records. + s0 - is commulative frequency sum of another symbols from parent context. + max(newFreq)= (s->Freq + 1), when (s0 == 1) + we have requirement (Ppmd7Context_OneState()->Freq <= 128) in BinSumm[] + so (s->Freq < 128) - is requirement for multi-symbol contexts + */ + newFreq = (Byte)(1 + ((2 * cf <= s0) ? (5 * cf > s0) : (2 * cf + s0 - 1) / (2 * s0) + 1)); + } + + // Create new single-symbol contexts from low order to high order in loop + + do + { + CTX_PTR c1; + /* = AllocContext(p); */ + if (p->HiUnit != p->LoUnit) + c1 = (CTX_PTR)(void *)(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)->Symbol = newSym; + ONE_STATE(c1)->Freq = newFreq; + SetSuccessor(ONE_STATE(c1), upBranch); + c1->Suffix = REF(c); + SetSuccessor(ps[--numPs], REF(c1)); + c = c1; + } + while (numPs != 0); + + return c; +} + + + +#define SwapStates(s) \ + { CPpmd_State tmp = s[0]; s[0] = s[-1]; s[-1] = tmp; } + + +void Ppmd7_UpdateModel(CPpmd7 *p); +MY_NO_INLINE +void Ppmd7_UpdateModel(CPpmd7 *p) +{ + CPpmd_Void_Ref maxSuccessor, minSuccessor; + CTX_PTR c, mc; + unsigned s0, ns; + + + + if (p->FoundState->Freq < MAX_FREQ / 4 && p->MinContext->Suffix != 0) + { + /* Update Freqs in Suffix Context */ + + 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); + Byte sym = p->FoundState->Symbol; + + if (s->Symbol != sym) + { + do + { + // s++; if (s->Symbol == sym) break; + s++; + } + while (s->Symbol != sym); + + if (s[0].Freq >= s[-1].Freq) + { + SwapStates(s); + s--; + } + } + + if (s->Freq < MAX_FREQ - 9) + { + s->Freq = (Byte)(s->Freq + 2); + c->Union2.SummFreq = (UInt16)(c->Union2.SummFreq + 2); + } + } + } + + + if (p->OrderFall == 0) + { + /* MAX ORDER context */ + /* (FoundState->Successor) is RAW-Successor. */ + p->MaxContext = p->MinContext = CreateSuccessors(p); + if (!p->MinContext) + { + RestartModel(p); + return; + } + SetSuccessor(p->FoundState, REF(p->MinContext)); + return; + } + + + /* NON-MAX ORDER context */ + + { + Byte *text = p->Text; + *text++ = p->FoundState->Symbol; + p->Text = text; + if (text >= p->UnitsStart) + { + RestartModel(p); + return; + } + maxSuccessor = REF(text); + } + + minSuccessor = SUCCESSOR(p->FoundState); + + if (minSuccessor) + { + // there is Successor for FoundState in MinContext. + // So the next context will be one order higher than MinContext. + + if (minSuccessor <= maxSuccessor) + { + // minSuccessor is RAW-Successor. So we will create real contexts records: + CTX_PTR cs = CreateSuccessors(p); + if (!cs) + { + RestartModel(p); + return; + } + minSuccessor = REF(cs); + } + + // minSuccessor now is real Context pointer that points to existing (Order+1) context + + if (--p->OrderFall == 0) + { + /* + if we move to MaxOrder context, then minSuccessor will be common Succesor for both: + MinContext that is (MaxOrder - 1) + MaxContext that is (MaxOrder) + so we don't need new RAW-Successor, and we can use real minSuccessor + as succssors for both MinContext and MaxContext. + */ + maxSuccessor = minSuccessor; + + /* + if (MaxContext != MinContext) + { + there was order fall from MaxOrder and we don't need current symbol + to transfer some RAW-Succesors to real contexts. + So we roll back pointer in raw data for one position. + } + */ + p->Text -= (p->MaxContext != p->MinContext); + } + } + else + { + /* + FoundState has NULL-Successor here. + And only root 0-order context can contain NULL-Successors. + We change Successor in FoundState to RAW-Successor, + And next context will be same 0-order root Context. + */ + SetSuccessor(p->FoundState, maxSuccessor); + minSuccessor = REF(p->MinContext); + } + + mc = p->MinContext; + c = p->MaxContext; + + p->MaxContext = p->MinContext = CTX(minSuccessor); + + if (c == mc) + return; + + // s0 : is pure Escape Freq + s0 = mc->Union2.SummFreq - (ns = mc->NumStats) - ((unsigned)p->FoundState->Freq - 1); + + do + { + unsigned ns1; + UInt32 sum; + + if ((ns1 = c->NumStats) != 1) + { + if ((ns1 & 1) == 0) + { + /* Expand for one UNIT */ + unsigned oldNU = ns1 >> 1; + unsigned i = U2I(oldNU); + if (i != U2I((size_t)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->Union4.Stats = STATS_REF(ptr); + } + } + sum = c->Union2.SummFreq; + /* max increase of Escape_Freq is 3 here. + total increase of Union2.SummFreq for all symbols is less than 256 here */ + sum += (UInt32)(2 * ns1 < ns) + 2 * ((unsigned)(4 * ns1 <= ns) & (sum <= 8 * ns1)); + /* original PPMdH uses 16-bit variable for (sum) here. + But (sum < 0x9000). So we don't truncate (sum) to 16-bit */ + // sum = (UInt16)sum; + } + else + { + // instead of One-symbol context we create 2-symbol context + CPpmd_State *s = (CPpmd_State*)AllocUnits(p, 0); + if (!s) + { + RestartModel(p); + return; + } + { + unsigned freq = c->Union2.State2.Freq; + // s = *ONE_STATE(c); + s->Symbol = c->Union2.State2.Symbol; + s->Successor_0 = c->Union4.State4.Successor_0; + s->Successor_1 = c->Union4.State4.Successor_1; + // SetSuccessor(s, c->Union4.Stats); // call it only for debug purposes to check the order of + // (Successor_0 and Successor_1) in LE/BE. + c->Union4.Stats = REF(s); + if (freq < MAX_FREQ / 4 - 1) + freq <<= 1; + else + freq = MAX_FREQ - 4; + // (max(s->freq) == 120), when we convert from 1-symbol into 2-symbol context + s->Freq = (Byte)freq; + // max(InitEsc = PPMD7_kExpEscape[*]) is 25. So the max(escapeFreq) is 26 here + sum = freq + p->InitEsc + (ns > 3); + } + } + + { + CPpmd_State *s = STATS(c) + ns1; + UInt32 cf = 2 * (sum + 6) * (UInt32)p->FoundState->Freq; + UInt32 sf = (UInt32)s0 + sum; + s->Symbol = p->FoundState->Symbol; + c->NumStats = (UInt16)(ns1 + 1); + SetSuccessor(s, maxSuccessor); + + if (cf < 6 * sf) + { + cf = (UInt32)1 + (cf > sf) + (cf >= 4 * sf); + sum += 3; + /* It can add (0, 1, 2) to Escape_Freq */ + } + else + { + cf = (UInt32)4 + (cf >= 9 * sf) + (cf >= 12 * sf) + (cf >= 15 * sf); + sum += cf; + } + + c->Union2.SummFreq = (UInt16)sum; + s->Freq = (Byte)cf; + } + c = SUFFIX(c); + } + while (c != mc); +} + + + +MY_NO_INLINE +static void Rescale(CPpmd7 *p) +{ + unsigned i, adder, sumFreq, escFreq; + CPpmd_State *stats = STATS(p->MinContext); + CPpmd_State *s = p->FoundState; + + /* Sort the list by Freq */ + if (s != stats) + { + CPpmd_State tmp = *s; + do + s[0] = s[-1]; + while (--s != stats); + *s = tmp; + } + + sumFreq = s->Freq; + escFreq = p->MinContext->Union2.SummFreq - sumFreq; + + /* + if (p->OrderFall == 0), adder = 0 : it's allowed to remove symbol from MAX Order context + if (p->OrderFall != 0), adder = 1 : it's NOT allowed to remove symbol from NON-MAX Order context + */ + + adder = (p->OrderFall != 0); + + #ifdef PPMD7_ORDER_0_SUPPPORT + adder |= (p->MaxOrder == 0); // we don't remove symbols from order-0 context + #endif + + sumFreq = (sumFreq + 4 + adder) >> 1; + i = (unsigned)p->MinContext->NumStats - 1; + s->Freq = (Byte)sumFreq; + + do + { + unsigned freq = (++s)->Freq; + escFreq -= freq; + freq = (freq + adder) >> 1; + sumFreq += freq; + s->Freq = (Byte)freq; + if (freq > s[-1].Freq) + { + CPpmd_State tmp = *s; + CPpmd_State *s1 = s; + do + { + s1[0] = s1[-1]; + } + while (--s1 != stats && freq > s1[-1].Freq); + *s1 = tmp; + } + } + while (--i); + + if (s->Freq == 0) + { + /* Remove all items with Freq == 0 */ + CPpmd7_Context *mc; + unsigned numStats, numStatsNew, n0, n1; + + i = 0; do { i++; } while ((--s)->Freq == 0); + + /* We increase (escFreq) for the number of removed symbols. + So we will have (0.5) increase for Escape_Freq in avarage per + removed symbol after Escape_Freq halving */ + escFreq += i; + mc = p->MinContext; + numStats = mc->NumStats; + numStatsNew = numStats - i; + mc->NumStats = (UInt16)(numStatsNew); + n0 = (numStats + 1) >> 1; + + if (numStatsNew == 1) + { + /* Create Single-Symbol context */ + unsigned freq = stats->Freq; + + do + { + escFreq >>= 1; + freq = (freq + 1) >> 1; + } + while (escFreq > 1); + + s = ONE_STATE(mc); + *s = *stats; + s->Freq = (Byte)freq; // (freq <= 260 / 4) + p->FoundState = s; + InsertNode(p, stats, U2I(n0)); + return; + } + + n1 = (numStatsNew + 1) >> 1; + if (n0 != n1) + { + // p->MinContext->Union4.Stats = STATS_REF(ShrinkUnits(p, stats, n0, n1)); + unsigned i0 = U2I(n0); + unsigned i1 = U2I(n1); + if (i0 != i1) + { + if (p->FreeList[i1] != 0) + { + void *ptr = RemoveNode(p, i1); + p->MinContext->Union4.Stats = STATS_REF(ptr); + MyMem12Cpy(ptr, (const void *)stats, n1); + InsertNode(p, stats, i0); + } + else + SplitBlock(p, stats, i0, i1); + } + } + } + { + CPpmd7_Context *mc = p->MinContext; + mc->Union2.SummFreq = (UInt16)(sumFreq + escFreq - (escFreq >> 1)); + // Escape_Freq halving here + p->FoundState = STATS(mc); + } +} + + +CPpmd_See *Ppmd7_MakeEscFreq(CPpmd7 *p, unsigned numMasked, UInt32 *escFreq) +{ + CPpmd_See *see; + const CPpmd7_Context *mc = p->MinContext; + unsigned numStats = mc->NumStats; + if (numStats != 256) + { + unsigned nonMasked = numStats - numMasked; + see = p->See[(unsigned)p->NS2Indx[(size_t)nonMasked - 1]] + + (nonMasked < (unsigned)SUFFIX(mc)->NumStats - numStats) + + 2 * (unsigned)(mc->Union2.SummFreq < 11 * numStats) + + 4 * (unsigned)(numMasked > nonMasked) + + p->HiBitsFlag; + { + // if (see->Summ) field is larger than 16-bit, we need only low 16 bits of Summ + unsigned summ = (UInt16)see->Summ; // & 0xFFFF + unsigned r = (summ >> see->Shift); + see->Summ = (UInt16)(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 && (const Byte *)c > p->Text) + p->MaxContext = p->MinContext = c; + else + Ppmd7_UpdateModel(p); +} + + +void Ppmd7_Update1(CPpmd7 *p) +{ + CPpmd_State *s = p->FoundState; + unsigned freq = s->Freq; + freq += 4; + p->MinContext->Union2.SummFreq = (UInt16)(p->MinContext->Union2.SummFreq + 4); + s->Freq = (Byte)freq; + if (freq > s[-1].Freq) + { + SwapStates(s); + p->FoundState = --s; + if (freq > MAX_FREQ) + Rescale(p); + } + NextContext(p); +} + + +void Ppmd7_Update1_0(CPpmd7 *p) +{ + CPpmd_State *s = p->FoundState; + CPpmd7_Context *mc = p->MinContext; + unsigned freq = s->Freq; + unsigned summFreq = mc->Union2.SummFreq; + p->PrevSuccess = (2 * freq > summFreq); + p->RunLength += (int)p->PrevSuccess; + mc->Union2.SummFreq = (UInt16)(summFreq + 4); + freq += 4; + s->Freq = (Byte)freq; + if (freq > MAX_FREQ) + Rescale(p); + NextContext(p); +} + + +/* +void Ppmd7_UpdateBin(CPpmd7 *p) +{ + unsigned freq = p->FoundState->Freq; + p->FoundState->Freq = (Byte)(freq + (freq < 128)); + p->PrevSuccess = 1; + p->RunLength++; + NextContext(p); +} +*/ + +void Ppmd7_Update2(CPpmd7 *p) +{ + CPpmd_State *s = p->FoundState; + unsigned freq = s->Freq; + freq += 4; + p->RunLength = p->InitRL; + p->MinContext->Union2.SummFreq = (UInt16)(p->MinContext->Union2.SummFreq + 4); + s->Freq = (Byte)freq; + if (freq > MAX_FREQ) + Rescale(p); + Ppmd7_UpdateModel(p); +} + + + +/* +PPMd Memory Map: +{ + [ 0 ] contains subset of original raw text, that is required to create context + records, Some symbols are not written, when max order context was reached + [ Text ] free area + [ UnitsStart ] CPpmd_State vectors and CPpmd7_Context records + [ LoUnit ] free area for CPpmd_State and CPpmd7_Context items +[ HiUnit ] CPpmd7_Context records + [ Size ] end of array +} + +These addresses don't cross at any time. +And the following condtions is true for addresses: + (0 <= Text < UnitsStart <= LoUnit <= HiUnit <= Size) + +Raw text is BYTE--aligned. +the data in block [ UnitsStart ... Size ] contains 12-bytes aligned UNITs. + +Last UNIT of array at offset (Size - 12) is root order-0 CPpmd7_Context record. +The code can free UNITs memory blocks that were allocated to store CPpmd_State vectors. +The code doesn't free UNITs allocated for CPpmd7_Context records. + +The code calls RestartModel(), when there is no free memory for allocation. +And RestartModel() changes the state to orignal start state, with full free block. + + +The code allocates UNITs with the following order: + +Allocation of 1 UNIT for Context record + - from free space (HiUnit) down to (LoUnit) + - from FreeList[0] + - AllocUnitsRare() + +AllocUnits() for CPpmd_State vectors: + - from FreeList[i] + - from free space (LoUnit) up to (HiUnit) + - AllocUnitsRare() + +AllocUnitsRare() + - if (GlueCount == 0) + { Glue lists, GlueCount = 255, allocate from FreeList[i]] } + - loop for all higher sized FreeList[...] lists + - from (UnitsStart - Text), GlueCount-- + - ERROR + + +Each Record with Context contains the CPpmd_State vector, where each +CPpmd_State contains the link to Successor. +There are 3 types of Successor: + 1) NULL-Successor - NULL pointer. NULL-Successor links can be stored + only in 0-order Root Context Record. + We use 0 value as NULL-Successor + 2) RAW-Successor - the link to position in raw text, + that "RAW-Successor" is being created after first + occurrence of new symbol for some existing context record. + (RAW-Successor > 0). + 3) RECORD-Successor - the link to CPpmd7_Context record of (Order+1), + that record is being created when we go via RAW-Successor again. + +For any successors at any time: the following condtions are true for Successor links: +(NULL-Successor < RAW-Successor < UnitsStart <= RECORD-Successor) + + +---------- Symbol Frequency, SummFreq and Range in Range_Coder ---------- + +CPpmd7_Context::SummFreq = Sum(Stats[].Freq) + Escape_Freq + +The PPMd code tries to fulfill the condition: + (SummFreq <= (256 * 128 = RC::kBot)) + +We have (Sum(Stats[].Freq) <= 256 * 124), because of (MAX_FREQ = 124) +So (4 = 128 - 124) is average reserve for Escape_Freq for each symbol. +If (CPpmd_State::Freq) is not aligned for 4, the reserve can be 5, 6 or 7. +SummFreq and Escape_Freq can be changed in Rescale() and *Update*() functions. +Rescale() can remove symbols only from max-order contexts. So Escape_Freq can increase after multiple calls of Rescale() for +max-order context. + +When the PPMd code still break (Total <= RC::Range) condition in range coder, +we have two ways to resolve that problem: + 1) we can report error, if we want to keep compatibility with original PPMd code that has no fix for such cases. + 2) we can reduce (Total) value to (RC::Range) by reducing (Escape_Freq) part of (Total) value. +*/ -- cgit v1.2.3-55-g6feb