CBitManip.h

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/********************************************************************************
**  This file is part of the ICF Framework. Copyright (C) Witold Gantzke & Kirill Lepskiy
**  ICF Framework may be used under the terms of the LGPL License v. 2.1 by the Free Software Foundation.
********************************************************************************/
 
#pragma once
 
 
// Qt includes
#include <QtCore/QtGlobal>
 
 
namespace istd
{
 
 
class CBitManip
{
public:
    CBitManip();
 
    int GetFirstBitIndex(quint32 bits) const;
 
    static CBitManip instance;
 
private:
    qint8 m_firstBitInByte[256];
};
 
 
// inline methods
 
inline int CBitManip::GetFirstBitIndex(quint32 bits) const
{
    quint16* words = (quint16*)&bits;
    quint8* bytes = (quint8*)&bits;
    if (words[0] != 0){
        if (bytes[0] != 0){
            return int(m_firstBitInByte[bytes[0]]);
        }
 
        return int(m_firstBitInByte[bytes[1]]);
    }
    else if (words[1] != 0){
        if (bytes[2] != 0){
            return int(m_firstBitInByte[bytes[2]]);
        }
 
        return int(m_firstBitInByte[bytes[3]]);
    }
 
    return -1;
}
 
 
} // namespace istd