diff options
Diffstat (limited to 'CPP/7zip/Compress/Z/ZDecoder.cpp')
-rwxr-xr-x | CPP/7zip/Compress/Z/ZDecoder.cpp | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/CPP/7zip/Compress/Z/ZDecoder.cpp b/CPP/7zip/Compress/Z/ZDecoder.cpp new file mode 100755 index 00000000..2415efd8 --- /dev/null +++ b/CPP/7zip/Compress/Z/ZDecoder.cpp @@ -0,0 +1,172 @@ +// ZDecoder.cpp + +#include "StdAfx.h" + +#include "ZDecoder.h" + +#include "../../../Common/Alloc.h" +#include "../../Common/InBuffer.h" +#include "../../Common/OutBuffer.h" +#include "../../Common/LSBFDecoder.h" + +namespace NCompress { +namespace NZ { + +static const UInt32 kBufferSize = (1 << 20); +static const Byte kNumBitsMask = 0x1F; +static const Byte kBlockModeMask = 0x80; +static const int kNumMinBits = 9; +static const int kNumMaxBits = 16; + +void CDecoder::Free() +{ + MyFree(_parents); + _parents = 0; + MyFree(_suffixes); + _suffixes = 0; + MyFree(_stack); + _stack = 0; +} + +bool CDecoder::Alloc(size_t numItems) +{ + Free(); + _parents = (UInt16 *)MyAlloc(numItems * sizeof(UInt16)); + if (_parents == 0) + return false; + _suffixes = (Byte *)MyAlloc(numItems * sizeof(Byte)); + if (_suffixes == 0) + return false; + _stack = (Byte *)MyAlloc(numItems * sizeof(Byte)); + return _stack != 0; +} + +CDecoder::~CDecoder() +{ + Free(); +} + +STDMETHODIMP CDecoder::CodeReal(ISequentialInStream *inStream, + ISequentialOutStream *outStream, const UInt64 * /* inSize */, const UInt64 * /* outSize */, + ICompressProgressInfo *progress) +{ + NStream::NLSBF::CBaseDecoder<CInBuffer> inBuffer; + COutBuffer outBuffer; + + if (!inBuffer.Create(kBufferSize)) + return E_OUTOFMEMORY; + inBuffer.SetStream(inStream); + inBuffer.Init(); + + if (!outBuffer.Create(kBufferSize)) + return E_OUTOFMEMORY; + outBuffer.SetStream(outStream); + outBuffer.Init(); + + int maxbits = _properties & kNumBitsMask; + if (maxbits < kNumMinBits || maxbits > kNumMaxBits) + return S_FALSE; + UInt32 numItems = 1 << maxbits; + bool blockMode = ((_properties & kBlockModeMask) != 0); + if (!blockMode) + return E_NOTIMPL; + + if (maxbits != _numMaxBits || _parents == 0 || _suffixes == 0 || _stack == 0) + { + if (!Alloc(numItems)) + return E_OUTOFMEMORY; + _numMaxBits = maxbits; + } + + UInt64 prevPos = 0; + int numBits = kNumMinBits; + UInt32 head = blockMode ? 257 : 256; + + bool needPrev = false; + + int keepBits = 0; + + _parents[256] = 0; // virus protection + _suffixes[256] = 0; + + for (;;) + { + if (keepBits < numBits) + keepBits = numBits * 8; + UInt32 symbol = inBuffer.ReadBits(numBits); + if (inBuffer.ExtraBitsWereRead()) + break; + keepBits -= numBits; + if (symbol >= head) + return S_FALSE; + if (blockMode && symbol == 256) + { + for (;keepBits > 0; keepBits--) + inBuffer.ReadBits(1); + numBits = kNumMinBits; + head = 257; + needPrev = false; + continue; + } + UInt32 cur = symbol; + int i = 0; + while (cur >= 256) + { + _stack[i++] = _suffixes[cur]; + cur = _parents[cur]; + } + _stack[i++] = (Byte)cur; + if (needPrev) + { + _suffixes[head - 1] = (Byte)cur; + if (symbol == head - 1) + _stack[0] = (Byte)cur; + } + while (i > 0) + outBuffer.WriteByte((_stack[--i])); + if (head < numItems) + { + needPrev = true; + _parents[head++] = (UInt16)symbol; + if (head > ((UInt32)1 << numBits)) + { + if (numBits < maxbits) + { + numBits++; + keepBits = numBits * 8; + } + } + } + else + needPrev = false; + + UInt64 nowPos = outBuffer.GetProcessedSize(); + if (progress != NULL && nowPos - prevPos > (1 << 18)) + { + prevPos = nowPos; + UInt64 packSize = inBuffer.GetProcessedSize(); + RINOK(progress->SetRatioInfo(&packSize, &nowPos)); + } + } + return outBuffer.Flush(); +} + +STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream, + ISequentialOutStream *outStream, const UInt64 *inSize, const UInt64 *outSize, + ICompressProgressInfo *progress) +{ + try { return CodeReal(inStream, outStream, inSize, outSize, progress); } + catch(const CInBufferException &e) { return e.ErrorCode; } + catch(const COutBufferException &e) { return e.ErrorCode; } + catch(...) { return S_FALSE; } +} + +STDMETHODIMP CDecoder::SetDecoderProperties2(const Byte *data, UInt32 size) +{ + if (size < 1) + return E_INVALIDARG; + _properties = data[0]; + return S_OK; +} + +}} |