From hexadecimal to string conversion C ++ / C / Qt?

Question

I interact with an external device that sends data in hexadecimal format. He has the form

> %abcdefg,+xxx.x,T,+yy.yy,T,+zz.zz,T,A*hhCRLF

• CR LF - carriage return line return
• hh-> checksum
• % abcdefg → header

Each character in the above packet is sent as a hexadecimal representation (xx, yy, abcd, etc. are replaced by actual numbers). The problem is at my end. I store it in const char *, and during the implicit conversion, the checksum says that 0x05 is converted to \ 0x05. Here \ 0 is the null character, ending my line. This is perceived as incorrect frames when it is not. Although I can change the implementation to handle raw bytes (in hexadecimal), I just wonder if there is another way out, because it greatly simplifies the processing of bytes. And this is what programmers should do.

Also at cutecom (on LINUX RHEL 4) I checked the data on the serial port, and we also noticed \0x05instead of 5 for the checksum. Please note that for storing incoming data I use

//store data from serial here
unsigned char Buffer[SIZE];  

//convert to a QString, here is where problem arises 
QString str((const char*)Buffer); of \0

QString "" Qt. , STL, ++ . - ? .

, :

#include <iostream>
#include <string>
#include <QString>
#include <QApplication>
#include <QByteArray>

using std::cout;
using std::string;
using std::endl;

int main(int argc,char* argv[])
{
    QApplication app(argc,argv);
    int x = 0x05;
    const char mydata[] = {
         0x00, 0x00, 0x03, 0x84, 0x78, 0x9c, 0x3b, 0x76,
               0xec, 0x18, 0xc3, 0x31, 0x0a, 0xf1, 0xcc, 0x99};
    QByteArray data = QByteArray::fromRawData(mydata, sizeof(mydata));
    printf("Hello %s\n",data.data());
    string str("Hello ");
    unsigned char ch[]={22,5,6,7,4};
    QString s((const char*)ch);
    qDebug("Hello %s",qPrintable(s));
    cout << str << x ;
    cout << "\nHello I am \0x05";
    cout << "\nHello I am " << "0x05";
    return app.exec();
}

Answer 1

0x05 char '\x05', ( , ), . C ++ a char . , 5 char, , , , . ( ASCII, ENQ char, .)

char '5', . ++ :

const char ch = 5; // '\0x5'
std::ostringstream oss;
oss << static_cast<int>(ch);
const std::string& str = oss.str(); // str now contains "5"

, C std . , .

Answer 2

QByteArray text = QByteArray::fromHex("517420697320677265617421");
text.data();            // returns "Qt is great!" 

Answer 3

, ++ char . ( ,), std::vector. , .

Answer 4

, ASCII . :

#include <iostream>
#include <string>
#include <QtCore/QString>
#include <QtCore/QByteArray>

using namespace std;

// test data from your comment
char data[] = { 0x49, 0x46, 0x50, 0x4a, 0x4b, 0x51, 0x52, 0x43, 0x2c, 0x31,
                0x32, 0x33, 0x2e, 0x34, 0x2c, 0x54, 0x2c, 0x41, 0x2c, 0x2b,
                0x33, 0x30, 0x2e, 0x30, 0x30, 0x2c, 0x41, 0x2c, 0x2d, 0x33,
                0x30, 0x2e, 0x30, 0x30, 0x2c, 0x41, 0x2a, 0x05, 0x0d, 0x0a };

// functor to remove control characters
struct toAscii
{
  // values >127 will be eliminated too
  char operator ()( char value ) const { if ( value < 32 && value != 0x0d && value != 0x0a ) return '.'; else return value; }
};

int main(int argc,char* argv[])
{
  string s;
  transform( &data[0], &data[sizeof(data)], back_inserter(s), toAscii() );

  cout << s; // STL string

  // convert to QString ( if necessary )
  QString str = QString::fromStdString( s );
  QByteArray d = str.toAscii();

  cout << d.data(); // QString

  return 0;
}

:

IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.

, - :

IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.
IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.
IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.
IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.
IFPJKQRC,123.4,T,A,+30.00,A,-30.00,A*.