gar::geo::BitFieldValue Class Reference

Helper class for BitFieldCoder that corresponds to one field value. More...

#include <BitFieldCoder.h>

Public Member Functions
	BitFieldValue ()=default
	Default constructor. More...
	BitFieldValue (const BitFieldValue &)=default
	Copy constructor. More...
	BitFieldValue (BitFieldValue &&)=default
	Move constructor. More...
	BitFieldValue (const std::string &name, unsigned offset, int signedWidth)
	~BitFieldValue ()=default
	Default destructor. More...
BitFieldValue &	operator= (const BitFieldValue &)=default
	Assignment operator. More...
long64	value (long64 bitfield) const
	calculate this field's value given an external 64 bit bitmap More...
void	set (long64 &bitfield, long64 value) const
const std::string &	name () const
unsigned	offset () const
unsigned	width () const
bool	isSigned () const
ulong64	mask () const
int	minValue () const
int	maxValue () const

Protected Attributes
ulong64	_mask {}
unsigned	_offset {}
unsigned	_width {}
int	_minVal {}
int	_maxVal {}
bool	_isSigned {}
std::string	_name

Detailed Description

Helper class for BitFieldCoder that corresponds to one field value.

Definition at line 49 of file BitFieldCoder.h.

Constructor & Destructor Documentation

gar::geo::BitFieldValue::BitFieldValue ( )

default

Default constructor.

gar::geo::BitFieldValue::BitFieldValue ( const BitFieldValue &  )

default

Copy constructor.

gar::geo::BitFieldValue::BitFieldValue ( BitFieldValue &&  )

default

Move constructor.

gar::geo::BitFieldValue::BitFieldValue	(	const std::string &	name,
		unsigned	offset,
		int	signedWidth
	)

The standard c'tor.

Parameters

name	name of the field
offset	offset of field
signedWidth	width of field, negative if field is signed

Definition at line 10 of file BitFieldCoder.cxx.

        : _mask(0), _offset( fieldOffset ), _width( abs( signedWidth ) ), _minVal(0), _maxVal(0), _isSigned( signedWidth < 0 ), _name( fieldName )
        {
            // sanity check
            if( _offset > 63 || _offset+_width > 64 ) {

                std::stringstream s ;
                s << " BitFieldValue '" << _name << "': out of range -  offset : "
                << _offset  << " width " << _width  ;

                throw( std::runtime_error( s.str() ) ) ;
            }

            _mask = ( ( 0x0001LL << _width ) - 1 ) << _offset ;


            // compute extreme values for later checks
            if( _isSigned ){

                _minVal =  ( 1LL << ( _width - 1 ) ) - ( 1LL << _width )  ;
                _maxVal =  ( 1LL << ( _width - 1 ) ) - 1 ;

            } else {

                _maxVal = 0x0001<<_width  ;
            }
        }

gar::geo::BitFieldValue::~BitFieldValue ( )

default

Default destructor.

Member Function Documentation

bool gar::geo::BitFieldValue::isSigned ( ) const

inline

True if field is interpreted as signed

Definition at line 87 of file BitFieldCoder.h.

{ return _isSigned ; }

ulong64 gar::geo::BitFieldValue::mask ( ) const

inline

The field's mask

Definition at line 90 of file BitFieldCoder.h.

{ return _mask ; }

int gar::geo::BitFieldValue::maxValue ( ) const

inline

Maximal value

Definition at line 96 of file BitFieldCoder.h.

{ return _maxVal;  }

int gar::geo::BitFieldValue::minValue ( ) const

inline

Minimal value

Definition at line 93 of file BitFieldCoder.h.

{ return _minVal;  }

const std::string& gar::geo::BitFieldValue::name ( ) const

inline

The field's name

Definition at line 78 of file BitFieldCoder.h.

{ return _name ; }

unsigned gar::geo::BitFieldValue::offset ( ) const

inline

The field's offset

Definition at line 81 of file BitFieldCoder.h.

{ return _offset ; }

BitFieldValue& gar::geo::BitFieldValue::operator= ( const BitFieldValue &  )

default

Assignment operator.

void gar::geo::BitFieldValue::set	(	long64 &	bitfield,
		long64	value
	)		const

Definition at line 59 of file BitFieldCoder.cxx.

                                                              {

            // check range
            if( in < _minVal || in > _maxVal  ) {

                std::stringstream s ;
                s << " BitFieldValue '" << _name << "': out of range : " << in
                << " for width " << _width  ;

                throw( std::runtime_error( s.str() ) );
            }

            field &= ~_mask ;  // zero out the field's range

            field |=  ( (  in  << _offset )  & _mask  ) ;

        }

long64 gar::geo::BitFieldValue::value

(

long64

bitfield

)

const

calculate this field's value given an external 64 bit bitmap

Definition at line 39 of file BitFieldCoder.cxx.

        {
            if(  _isSigned   )
            {
                long64 val = ( id & _mask ) >> _offset ;
                if( ( val  & ( 1LL << ( _width - 1 ) ) ) != 0 )
                {
                    // negative value
                    val -= ( 1LL << _width );
                }

                return val ;
            }
            else
            {
                return  ( id & _mask ) >> _offset ;
            }
        }

unsigned gar::geo::BitFieldValue::width ( ) const

inline

The field's width

Definition at line 84 of file BitFieldCoder.h.

{ return _width ; }

Member Data Documentation

bool gar::geo::BitFieldValue::_isSigned {}

protected

Definition at line 105 of file BitFieldCoder.h.

ulong64 gar::geo::BitFieldValue::_mask {}

protected

Definition at line 100 of file BitFieldCoder.h.

int gar::geo::BitFieldValue::_maxVal {}

protected

Definition at line 104 of file BitFieldCoder.h.

int gar::geo::BitFieldValue::_minVal {}

protected

Definition at line 103 of file BitFieldCoder.h.

std::string gar::geo::BitFieldValue::_name

protected

Definition at line 106 of file BitFieldCoder.h.

unsigned gar::geo::BitFieldValue::_offset {}

protected

Definition at line 101 of file BitFieldCoder.h.

unsigned gar::geo::BitFieldValue::_width {}

protected

Definition at line 102 of file BitFieldCoder.h.

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

• garsoft/Geometry/BitFieldCoder.h
• garsoft/Geometry/BitFieldCoder.cxx