diff options
author | 2012-02-12 17:55:51 +0000 | |
---|---|---|
committer | 2012-02-12 17:55:51 +0000 | |
commit | d75dbab0de7da33196f08f0cf7992d906ffbb832 (patch) | |
tree | d9120844b308fa2ac9844c182a86b79feddb84f3 /src/lib/lib7z/Ppmd8Enc.c | |
parent | f594641814167d5de00ee2a0d6925c42e61fecc4 (diff) |
Add LZMA codec and .7z container support [David Haywood, R. Belmont]
Diffstat (limited to 'src/lib/lib7z/Ppmd8Enc.c')
-rw-r--r-- | src/lib/lib7z/Ppmd8Enc.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/lib/lib7z/Ppmd8Enc.c b/src/lib/lib7z/Ppmd8Enc.c new file mode 100644 index 00000000000..8da727eb25a --- /dev/null +++ b/src/lib/lib7z/Ppmd8Enc.c @@ -0,0 +1,161 @@ +/* Ppmd8Enc.c -- PPMdI Encoder +2010-04-16 : Igor Pavlov : Public domain +This code is based on: + PPMd var.I (2002): Dmitry Shkarin : Public domain + Carryless rangecoder (1999): Dmitry Subbotin : Public domain */ + +#include "Ppmd8.h" + +#define kTop (1 << 24) +#define kBot (1 << 15) + +void Ppmd8_RangeEnc_FlushData(CPpmd8 *p) +{ + unsigned i; + for (i = 0; i < 4; i++, p->Low <<= 8 ) + p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24)); +} + +static void RangeEnc_Normalize(CPpmd8 *p) +{ + while ((p->Low ^ (p->Low + p->Range)) < kTop || + (p->Range < kBot && ((p->Range = (0 - p->Low) & (kBot - 1)), 1))) + { + p->Stream.Out->Write(p->Stream.Out, (Byte)(p->Low >> 24)); + p->Range <<= 8; + p->Low <<= 8; + } +} + +static void RangeEnc_Encode(CPpmd8 *p, UInt32 start, UInt32 size, UInt32 total) +{ + p->Low += start * (p->Range /= total); + p->Range *= size; + RangeEnc_Normalize(p); +} + +static void RangeEnc_EncodeBit_0(CPpmd8 *p, UInt32 size0) +{ + p->Range >>= 14; + p->Range *= size0; + RangeEnc_Normalize(p); +} + +static void RangeEnc_EncodeBit_1(CPpmd8 *p, UInt32 size0) +{ + p->Low += size0 * (p->Range >>= 14); + p->Range *= ((1 << 14) - size0); + RangeEnc_Normalize(p); +} + + +#define MASK(sym) ((signed char *)charMask)[sym] + +void Ppmd8_EncodeSymbol(CPpmd8 *p, int symbol) +{ + size_t charMask[256 / sizeof(size_t)]; + if (p->MinContext->NumStats != 0) + { + CPpmd_State *s = Ppmd8_GetStats(p, p->MinContext); + UInt32 sum; + unsigned i; + if (s->Symbol == symbol) + { + RangeEnc_Encode(p, 0, s->Freq, p->MinContext->SummFreq); + p->FoundState = s; + Ppmd8_Update1_0(p); + return; + } + p->PrevSuccess = 0; + sum = s->Freq; + i = p->MinContext->NumStats; + do + { + if ((++s)->Symbol == symbol) + { + RangeEnc_Encode(p, sum, s->Freq, p->MinContext->SummFreq); + p->FoundState = s; + Ppmd8_Update1(p); + return; + } + sum += s->Freq; + } + while (--i); + + PPMD_SetAllBitsIn256Bytes(charMask); + MASK(s->Symbol) = 0; + i = p->MinContext->NumStats; + do { MASK((--s)->Symbol) = 0; } while (--i); + RangeEnc_Encode(p, sum, p->MinContext->SummFreq - sum, p->MinContext->SummFreq); + } + else + { + UInt16 *prob = Ppmd8_GetBinSumm(p); + CPpmd_State *s = Ppmd8Context_OneState(p->MinContext); + if (s->Symbol == symbol) + { + RangeEnc_EncodeBit_0(p, *prob); + *prob = (UInt16)PPMD_UPDATE_PROB_0(*prob); + p->FoundState = s; + Ppmd8_UpdateBin(p); + return; + } + else + { + RangeEnc_EncodeBit_1(p, *prob); + *prob = (UInt16)PPMD_UPDATE_PROB_1(*prob); + p->InitEsc = PPMD8_kExpEscape[*prob >> 10]; + PPMD_SetAllBitsIn256Bytes(charMask); + MASK(s->Symbol) = 0; + p->PrevSuccess = 0; + } + } + for (;;) + { + UInt32 escFreq; + CPpmd_See *see; + CPpmd_State *s; + UInt32 sum; + unsigned i, numMasked = p->MinContext->NumStats; + do + { + p->OrderFall++; + if (!p->MinContext->Suffix) + return; /* EndMarker (symbol = -1) */ + p->MinContext = Ppmd8_GetContext(p, p->MinContext->Suffix); + } + while (p->MinContext->NumStats == numMasked); + + see = Ppmd8_MakeEscFreq(p, numMasked, &escFreq); + s = Ppmd8_GetStats(p, p->MinContext); + sum = 0; + i = p->MinContext->NumStats + 1; + do + { + int cur = s->Symbol; + if (cur == symbol) + { + UInt32 low = sum; + CPpmd_State *s1 = s; + do + { + sum += (s->Freq & (int)(MASK(s->Symbol))); + s++; + } + while (--i); + RangeEnc_Encode(p, low, s1->Freq, sum + escFreq); + Ppmd_See_Update(see); + p->FoundState = s1; + Ppmd8_Update2(p); + return; + } + sum += (s->Freq & (int)(MASK(cur))); + MASK(cur) = 0; + s++; + } + while (--i); + + RangeEnc_Encode(p, sum, escFreq, sum + escFreq); + see->Summ = (UInt16)(see->Summ + sum + escFreq); + } +} |