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Crc32.cpp
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173 lines (138 loc) · 4.99 KB
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#include "Base.h"
#include "Crc32.h"
#include "FileSystemUtils.h"
NS_BEGIN
static constexpr auto CRC_BUFFER_SIZE = 8192;
//#################################################################################################
CCrc32::CCrc32(const uint32_t nPolynomial)
{ // The default polynomial of "0xEDB88320" is the official one used by CRC32 in PKZip.
// Often times the polynomial shown reversed as 0x04C11DB7.
m_pnCrc32Table = std::make_unique<uint32_t[]>(256);
for(uint16_t i = 0; i < 256; ++i)
{
uint32_t nCrc = i;
for(uint8_t j = 0; j < 8; ++j)
{
if(nCrc & 1)
nCrc = (nCrc >> 1) ^ nPolynomial;
else
nCrc >>= 1;
}
m_pnCrc32Table[i] = nCrc;
}
}
//#################################################################################################
bool CCrc32::Crc32File(PCNSTR szFilename, uint32_t &nCrc32) const
{
bool bResult = false;
nCrc32 = (uint32_t)-1;
if(szFilename == nullptr)
return bResult;
NHANDLE hFile = INVALID_NHANDLE;
if(FileCreate(szFilename, EFM_ExistingReadOnly, hFile) == FW_NO_ERROR)
{
auto pBuffer = std::make_unique<BYTE[]>(CRC_BUFFER_SIZE);
size_t nBytesRead;
bool bSuccess = (FileRead(hFile, pBuffer.get(), CRC_BUFFER_SIZE, nBytesRead) == FW_NO_ERROR);
while(bSuccess && nBytesRead)
{
for(size_t n = 0; n < nBytesRead; ++n)
nCrc32 = (nCrc32 >> 8) ^ m_pnCrc32Table[pBuffer[n] ^ (nCrc32 & 0x000000FF)];
bSuccess = (FileRead(hFile, pBuffer.get(), CRC_BUFFER_SIZE, nBytesRead) == FW_NO_ERROR);
}
nCrc32 = ~nCrc32;
bResult = true;
FileClose(hFile);
}
return bResult;
}
//#################################################################################################
bool CCrc32::Crc32Buffer(PCBYTE pBuffer, const size_t nSize, uint32_t &nCrc32) const
{
if(pBuffer == nullptr)
return false;
nCrc32 = (uint32_t)-1;
for(size_t n = 0; n < nSize; ++n)
nCrc32 = (nCrc32 >> 8) ^ m_pnCrc32Table[pBuffer[n] ^ (nCrc32 & 0x000000FF)];
nCrc32 = ~nCrc32;
return true;
}
//#################################################################################################
bool CCrc32::Crc32StreamInit(uint32_t &nCrc32) const noexcept
{
nCrc32 = (uint32_t)-1;
return true;
}
//#################################################################################################
void CCrc32::Crc32Stream(PCBYTE pBuffer, const size_t nSize, uint32_t &nCrc32) const noexcept
{
for(size_t n = 0; n < nSize; ++n)
nCrc32 = (nCrc32 >> 8) ^ m_pnCrc32Table[pBuffer[n] ^ (nCrc32 & 0x000000FF)];
}
//#################################################################################################
void CCrc32::Crc32StreamEnd(uint32_t &nCrc32) noexcept
{
nCrc32 = ~nCrc32;
}
//#################################################################################################
CCrc32Mpeg2::CCrc32Mpeg2(void)
{ // "0xEDB88320" is the official polynomial used by CRC32 in PKZip.
// Often times the polynomial shown reversed as 0x04C11DB7.
m_pnCrc32Table = std::make_unique<uint32_t[]>(256);
for(uint16_t i = 0; i < 256; ++i)
{
uint32_t nCrc = i;
nCrc <<= 24;
for(uint8_t j = 8; j > 0; --j)
{
if(nCrc & 0x80000000)
nCrc = (nCrc << 1) ^ 0x04C11DB7;
else
nCrc <<= 1;
}
m_pnCrc32Table[i] = nCrc;
}
}
//#################################################################################################
bool CCrc32Mpeg2::Crc32File(PCNSTR szFilename, uint32_t &nCrc32) const
{
bool bResult = false;
nCrc32 = (uint32_t)-1;
NHANDLE hFile = INVALID_NHANDLE;
if(FileCreate(szFilename, EFM_ExistingReadOnly, hFile) == FW_NO_ERROR)
{
auto pBuffer = std::make_unique<BYTE[]>(CRC_BUFFER_SIZE);
size_t nBytesRead;
bool bSuccess = (FileRead(hFile, pBuffer.get(), CRC_BUFFER_SIZE, nBytesRead) == FW_NO_ERROR);
while(bSuccess && nBytesRead)
{
for(size_t n = 0; n < nBytesRead; ++n)
nCrc32 = m_pnCrc32Table[(nCrc32 >> 24) ^ (pBuffer[n] & 0xFF)] ^ (nCrc32 << 8);
bSuccess = (FileRead(hFile, pBuffer.get(), CRC_BUFFER_SIZE, nBytesRead) == FW_NO_ERROR);
}
bResult = true;
FileClose(hFile);
}
return bResult;
}
//#################################################################################################
bool CCrc32Mpeg2::Crc32Buffer(PCBYTE pBuffer, const size_t nSize, uint32_t &nCrc32) const
{
nCrc32 = (uint32_t)-1;
for(size_t n = 0; n < nSize; ++n)
nCrc32 = m_pnCrc32Table[(nCrc32 >> 24) ^ (pBuffer[n] & 0xFF)] ^ (nCrc32 << 8);
return true;
}
//#################################################################################################
bool CCrc32Mpeg2::Crc32StreamInit(uint32_t &nCrc32) noexcept
{
nCrc32 = (uint32_t)-1;
return true;
}
//#################################################################################################
void CCrc32Mpeg2::Crc32Stream(PCBYTE pBuffer, const size_t nSize, uint32_t &nCrc32) const noexcept
{
for(size_t n = 0; n < nSize; ++n)
nCrc32 = m_pnCrc32Table[(nCrc32 >> 24) ^ (pBuffer[n] & 0xFF)] ^ (nCrc32 << 8);
}
NS_END