QByteArray Chunk Cutter

qba_cutter.hpp

#include <QByteArray>

/// Extension of class QByteArray:
/// allows cut off a chunk from begining of byte array
/// chunk is equivalent quint8, quint16 or quint32 by length
class qBA_cutter: public QByteArray
{
 private:
    union {
        quint16   sshort;
        quint8    sbyte[2];
    } SHORT_16_BYTE;
    union {
        quint32   slong;
        quint16   sshort[2];
        quint8    sbyte[4];
    } LONG_32_BYTE;

 public:
    qBA_cutter();
    qBA_cutter(const char *_array, int _size = -1);
    ~qBA_cutter();

    void assign(const char *_array, int _size) { this->clear(); this->append(_array, _size); }
    void skipBytes(int n) { this->remove(0, n); }
    quint8 cutoffByte() {
      if(!this->isEmpty()) {
        quint8 iRet = this->at(0);
        this->remove(0, 1);
        return iRet;
      }
      else
        return 0;
    }
    
    quint16 cutoffShort() { 
      if(!this->isEmpty() && this->size() >= 2) {
        SHORT_16_BYTE.sbyte[0] = this->at(0);
        SHORT_16_BYTE.sbyte[1] = this->at(1);
        this->remove(0, 2);
      }
      else SHORT_16_BYTE.sshort = 0;
  
    return SHORT_16_BYTE.sshort;
  }
    quint32 cutoffLong() { 
      if(!this->isEmpty() && this->size() >= 4) {
          LONG_32_BYTE.sbyte[0] = this->at(0);
          LONG_32_BYTE.sbyte[1] = this->at(1);
          LONG_32_BYTE.sbyte[2] = this->at(2);
          LONG_32_BYTE.sbyte[3] = this->at(3);
          this->remove(0, 4);
      }
      else LONG_32_BYTE.slong = 0;
  
      return LONG_32_BYTE.slong;
    }
};