Trk::BitField< T > Class Template Reference

A class managing bits belonging to a range of bits. More...

#include <BitField.h>

Collaboration diagram for Trk::BitField< T >:

Public Member Functions
	BitField (unsigned int offset_, unsigned int bits_)
	constructor, taking the offset (position of the first bit) and the number of bits No range checking is performed so the caller has to ensure that the field does not fall outside the range of the memory of class T Class T must support bit operations More...
bool	encode (unsigned int value, T &id) const
	encode a value into id, return false if the value is out of range More...
unsigned int	decode (T id) const
	returns the result of decode the input id More...

Private Attributes
unsigned int	m_offset
unsigned int	m_bits
	position of the first bit manipulated by the BitField More...
unsigned int	m_maxValue
	number of m_bits that the BitField is allowed to manipulate More...
unsigned int	m_mask
	maximum allow value More...

Detailed Description

template<class T>
class Trk::BitField< T >

A class managing bits belonging to a range of bits.

Definition at line 14 of file BitField.h.

Constructor & Destructor Documentation

BitField()

template<class T >

BitField::BitField	(	unsigned int	offset_,
		unsigned int	bits_
	)

constructor, taking the offset (position of the first bit) and the number of bits No range checking is performed so the caller has to ensure that the field does not fall outside the range of the memory of class T Class T must support bit operations

Definition at line 57 of file BitField.h.

                                                                 : m_offset(offset_),m_bits(bits_) {
    // calculate m_mask
    m_mask = 0;
    for( unsigned int bit = m_offset; bit < m_offset + m_bits; ++bit ) {
      m_mask |= (1<<bit);
    }
    // silly way of calculating 2^m_bits
    m_maxValue = 1;
    for( unsigned int i=0;i<m_bits;++i ) { m_maxValue *= 2;}
  }

Member Function Documentation

decode()

template<class T >

unsigned int BitField::decode

(

T

id

)

const

returns the result of decode the input id

Definition at line 51 of file BitField.h.

                                               {
    // apply m_mask and shift with m_offset
    return (id & m_mask) >> m_offset;
  }

encode()

template<class T >

bool BitField::encode	(	unsigned int	value,
		T &	id
	)		const

encode a value into id, return false if the value is out of range

Definition at line 37 of file BitField.h.

                                                            {
    // check that the value is in range
    if( value >= m_maxValue ) { return false;}
    
    // clear m_bits
    id &= ~m_mask;
    
    // set m_bits
    id |= (value<<m_offset);
    
    return true;
  }

Member Data Documentation

m_bits

template<class T >

unsigned int Trk::BitField< T >::m_bits

private

position of the first bit manipulated by the BitField

Definition at line 31 of file BitField.h.

m_mask

template<class T >

unsigned int Trk::BitField< T >::m_mask

private

maximum allow value

Definition at line 33 of file BitField.h.

m_maxValue

template<class T >

unsigned int Trk::BitField< T >::m_maxValue

private

number of m_bits that the BitField is allowed to manipulate

Definition at line 32 of file BitField.h.

m_offset

template<class T >

unsigned int Trk::BitField< T >::m_offset

private

Definition at line 30 of file BitField.h.

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The documentation for this class was generated from the following file:

• BitField.h