compare Qt's CRC and boost's crc algorithms

DungeonLords

I want to calc CRC using not Qt's qChecksum but using boost library. CRC algo should be the same. How calc?

DungeonLords

Qt use CRC algo "ISO/IEC 3309" with well-known alias "CRC-16/ISO-HDLC, CRC-16/ISO-IEC-14443-3-B, CRC-16/X-25, CRC-B, X-25", see details. This code to compare Qt's CRC and boost's crc algorithms

#include <QCoreApplication>
#include <boost/crc.hpp>
using namespace boost;
typedef crc_optimal<16, 0x1021, 0xffff, 0xffff, true, true> crc_16_X25;

QString u16Hex(const quint16 value){
    return QString("0x"+QString("%1").arg(value, 4, 16, QChar('0')).toUpper());
}

void calc(){
    std::array<quint16, 3> arr= {0x0000, 0x0000}; //there is two data elements and third element to keep crc itself
    crc_16_X25 crc_boost{};
    //crc.reset(); //no need because we calc crc first time; use in case of reuse
    crc_boost.process_block(arr.cbegin(), &arr.at(1)); //calc crc of two elements
    arr[2]= crc_boost.checksum();
    QByteArray b= QByteArray::fromHex("0000");
    const quint16 crc_Qt= qChecksum(b);
    qDebug() << "Qt" << u16Hex(crc_Qt) << "boost" << u16Hex(arr[2]) ;
}

int main(int argc, char *argv[]){
    QCoreApplication a(argc, argv);
    calc();

    QMetaObject::invokeMethod(&a, "quit", Qt::QueuedConnection);
    return a.exec();
}

Output:

Qt "0x0F47" boost "0x0F47"

See how to build boost library for CRC part here