bool Qca2ByteArrayChecksumAlgorithm::calculateChecksum( QString* result,
const Okteta::AbstractByteArrayModel* model, const Okteta::AddressRange& range ) const
{
QCA::Hash hash( mType );
// TODO: find a way without needing to copy, perhaps by smart iterator which can return spans of original data
// TODO: see if buffer size could be a value which matches the algorithm and qca2
char buffer[CalculatedByteCountSignalLimit];
int bufferLength = CalculatedByteCountSignalLimit;
Okteta::Address nextBlockEnd = range.start() + CalculatedByteCountSignalLimit;
for( Okteta::Address i = range.start(); i<=range.end(); i+=CalculatedByteCountSignalLimit )
{
if( range.end() < i+CalculatedByteCountSignalLimit )
bufferLength = range.end() - i + 1;
model->copyTo( reinterpret_cast<Okteta::Byte*>(buffer), i, bufferLength );
hash.update( buffer, bufferLength );
if( i >= nextBlockEnd )
{
nextBlockEnd += CalculatedByteCountSignalLimit;
emit calculatedBytes( range.localIndex(i)+1 );
}
}
const QByteArray hashResult = hash.final().toByteArray();
*result = QCA::arrayToHex( hashResult );
return true;
}
bool Adler32ByteArrayChecksumAlgorithm::calculateChecksum( QString* result,
const Okteta::AbstractByteArrayModel* model, const Okteta::AddressRange& range ) const
{
quint32 a = 1;
quint32 b = 0;
// TODO: this is the "inefficient but straightforward implementation" from the Wikipedia entry, search for improved
Okteta::Address nextBlockEnd = range.start() + CalculatedByteCountSignalLimit;
for( Okteta::Address i = range.start(); i<=range.end(); ++i )
{
a = (a + model->byte( i )) % MOD_ADLER;
b = (b + a) % MOD_ADLER;
if( i >= nextBlockEnd )
{
nextBlockEnd += CalculatedByteCountSignalLimit;
emit calculatedBytes( range.localIndex(i)+1 );
}
}
const quint32 sum = (b << 16) | a;
*result = QString::fromLatin1("%1").arg( sum, 8, 16, QChar::fromLatin1('0') );
return true;
}
quint16 ModSum16ByteArrayChecksumAlgorithm::calculateModSumWithBigEndian( const Okteta::AbstractByteArrayModel* model, const Okteta::AddressRange& range ) const
{
quint16 modSum = 0x0000;
Okteta::Address nextBlockEnd = range.start() + CalculatedByteCountSignalLimit;
// TODO: move padding checks into extra code before and after loop
for( Okteta::Address i = range.start(); i<=range.end(); ++i )
{
quint16 value = (quint16)( (quint8)(model->byte( i )) ) << 8;
++i;
if( i<=range.end() )
value |= (quint16)( (quint8)(model->byte( i )) );
modSum += value;
#if 0
const uchar value = (crcBits & 0xFF) + model->byte( i );
crcBits >>= 8;
crcBits ^= lookupTable[value];
#endif
if( i >= nextBlockEnd )
{
nextBlockEnd += CalculatedByteCountSignalLimit;
emit calculatedBytes( range.localIndex(i)+1 );
}
}
return modSum;
}
