Simone
d074cc7c07
Plugin: ns7zip v2.0.0 Architectures: x86-ansi, x86-unicode, amd64-unicode License: LGPL-2.1-or-later
91 lines
2.3 KiB
C++
91 lines
2.3 KiB
C++
// FindSignature.cpp
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#include "StdAfx.h"
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#include <string.h>
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#include "../../../Common/MyBuffer.h"
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#include "../../Common/StreamUtils.h"
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#include "FindSignature.h"
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HRESULT FindSignatureInStream(ISequentialInStream *stream,
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const Byte *signature, unsigned signatureSize,
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const UInt64 *limit, UInt64 &resPos)
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{
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resPos = 0;
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CByteBuffer byteBuffer2(signatureSize);
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RINOK(ReadStream_FALSE(stream, byteBuffer2, signatureSize))
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if (memcmp(byteBuffer2, signature, signatureSize) == 0)
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return S_OK;
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const size_t kBufferSize = 1 << 16;
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CByteBuffer byteBuffer(kBufferSize);
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Byte *buffer = byteBuffer;
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size_t numPrevBytes = signatureSize - 1;
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memcpy(buffer, (const Byte *)byteBuffer2 + 1, numPrevBytes);
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resPos = 1;
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for (;;)
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{
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if (limit)
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if (resPos > *limit)
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return S_FALSE;
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do
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{
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const size_t numReadBytes = kBufferSize - numPrevBytes;
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UInt32 processedSize;
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RINOK(stream->Read(buffer + numPrevBytes, (UInt32)numReadBytes, &processedSize))
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numPrevBytes += (size_t)processedSize;
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if (processedSize == 0)
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return S_FALSE;
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}
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while (numPrevBytes < signatureSize);
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const size_t numTests = numPrevBytes - signatureSize + 1;
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for (size_t pos = 0; pos < numTests; pos++)
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{
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const Byte b = signature[0];
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for (; buffer[pos] != b && pos < numTests; pos++);
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if (pos == numTests)
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break;
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if (memcmp(buffer + pos, signature, signatureSize) == 0)
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{
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resPos += pos;
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return S_OK;
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}
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}
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resPos += numTests;
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numPrevBytes -= numTests;
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memmove(buffer, buffer + numTests, numPrevBytes);
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}
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}
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namespace NArchive {
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HRESULT ReadZeroTail(ISequentialInStream *stream, bool &areThereNonZeros, UInt64 &numZeros, UInt64 maxSize);
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HRESULT ReadZeroTail(ISequentialInStream *stream, bool &areThereNonZeros, UInt64 &numZeros, UInt64 maxSize)
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{
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areThereNonZeros = false;
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numZeros = 0;
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const size_t kBufSize = 1 << 11;
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Byte buf[kBufSize];
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for (;;)
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{
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UInt32 size = 0;
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RINOK(stream->Read(buf, kBufSize, &size))
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if (size == 0)
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return S_OK;
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for (UInt32 i = 0; i < size; i++)
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if (buf[i] != 0)
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{
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areThereNonZeros = true;
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numZeros += i;
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return S_OK;
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}
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numZeros += size;
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if (numZeros > maxSize)
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return S_OK;
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}
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}
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}
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