93 lines
2.1 KiB
C++
93 lines
2.1 KiB
C++
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// ZlibDecoder.cpp
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#include "StdAfx.h"
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#include "../Common/StreamUtils.h"
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#include "ZlibDecoder.h"
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namespace NCompress {
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namespace NZlib {
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#define DEFLATE_TRY_BEGIN try {
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#define DEFLATE_TRY_END } catch(...) { return S_FALSE; }
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#define ADLER_MOD 65521
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#define ADLER_LOOP_MAX 5550
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UInt32 Adler32_Update(UInt32 adler, const Byte *buf, size_t size)
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{
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UInt32 a = adler & 0xFFFF;
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UInt32 b = (adler >> 16) & 0xFFFF;
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while (size > 0)
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{
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unsigned curSize = (size > ADLER_LOOP_MAX) ? ADLER_LOOP_MAX : (unsigned )size;
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unsigned i;
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for (i = 0; i < curSize; i++)
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{
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a += buf[i];
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b += a;
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}
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buf += curSize;
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size -= curSize;
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a %= ADLER_MOD;
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b %= ADLER_MOD;
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}
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return (b << 16) + a;
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}
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STDMETHODIMP COutStreamWithAdler::Write(const void *data, UInt32 size, UInt32 *processedSize)
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{
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HRESULT result = S_OK;
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if (_stream)
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result = _stream->Write(data, size, &size);
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_adler = Adler32_Update(_adler, (const Byte *)data, size);
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_size += size;
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if (processedSize)
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*processedSize = size;
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return result;
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}
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STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream, ISequentialOutStream *outStream,
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const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress)
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{
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DEFLATE_TRY_BEGIN
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if (!AdlerStream)
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AdlerStream = AdlerSpec = new COutStreamWithAdler;
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if (!DeflateDecoder)
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{
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DeflateDecoderSpec = new NDeflate::NDecoder::CCOMCoder;
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DeflateDecoderSpec->ZlibMode = true;
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DeflateDecoder = DeflateDecoderSpec;
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}
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if (inSize && *inSize < 2)
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return S_FALSE;
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Byte buf[2];
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RINOK(ReadStream_FALSE(inStream, buf, 2));
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if (!IsZlib(buf))
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return S_FALSE;
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AdlerSpec->SetStream(outStream);
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AdlerSpec->Init();
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UInt64 inSize2 = 0;
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if (inSize)
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inSize2 = *inSize - 2;
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HRESULT res = DeflateDecoder->Code(inStream, AdlerStream, inSize ? &inSize2 : NULL, outSize, progress);
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AdlerSpec->ReleaseStream();
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if (res == S_OK)
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{
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const Byte *p = DeflateDecoderSpec->ZlibFooter;
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UInt32 adler = ((UInt32)p[0] << 24) | ((UInt32)p[1] << 16) | ((UInt32)p[2] << 8) | p[3];
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if (adler != AdlerSpec->GetAdler())
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return S_FALSE;
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}
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return res;
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DEFLATE_TRY_END
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}
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}}
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