ModuloComputer.ih

/**
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 **/
 
/**
 * @file ModuloComputer.ih
 * @author David Coeurjolly (\c david.coeurjolly@liris.cnrs.fr )
 * Laboratoire d'InfoRmatique en Image et Systèmes d'information - LIRIS (CNRS, UMR 5205), CNRS, France
 *
 * @date 2010/07/02
 *
 * Implementation of inline methods defined in ModuloComputer.h
 *
 * This file is part of the DGtal library.
 */
 
 
//////////////////////////////////////////////////////////////////////////////
#include <cstdlib>
//////////////////////////////////////////////////////////////////////////////
 
///////////////////////////////////////////////////////////////////////////////
// IMPLEMENTATION of inline methods.
///////////////////////////////////////////////////////////////////////////////
 
///////////////////////////////////////////////////////////////////////////////
// ----------------------- Standard services ------------------------------
 
 
/**
 * Initializes the modulo computer with the value [m].
 * @param m any non-zero integer.
 */
template <typename T>
inline
DGtal::ModuloComputer<T>::ModuloComputer( UnsignedIntegerParamType  m )
  : k( m )
{
}
 
///////////////////////////////////////////////////////////////////////////////
// Interface - public :
 
 
    
/**
 * Increment the value [i] modulo.
 * @param i any value between 0 and [k] (excluded).
 */
template <typename T>
inline
void 
DGtal::ModuloComputer<T>::increment( UnsignedInteger & i ) const
{
  if ( ++i == k ) i = 0;
}
 
 
/**
 * Decrement the value [i] modulo.
 * @param i any value between 0 and [k] (excluded).
 */
template <typename T>
inline
void 
DGtal::ModuloComputer<T>::decrement( UnsignedInteger & i ) const
{
  if ( i == 0 ) i = k;
  --i;
}
 
 
/**
 * @param i any value between 0 and [k] (excluded).
 * @return the incremented value of [i] modulo [k].
 */
template <typename T>
inline
typename DGtal::ModuloComputer<T>::UnsignedInteger 
DGtal::ModuloComputer<T>::next( UnsignedIntegerParamType i ) const
{
  
  return ( (i+1) == k ) ? 0 : (i+1);
}
 
 
/**
 * @param i any value between 0 and [k] (excluded).
 * @return the decremented value of [i] modulo [k].
 */
template <typename T>
inline
typename DGtal::ModuloComputer<T>::UnsignedInteger 
DGtal::ModuloComputer<T>::previous( UnsignedIntegerParamType i ) const
{
  return ( i == 0 ) ? k - 1 : i - 1;
}
 
 
/**
 * @param i any integer value.
 * @return the value of [i] modulo [k].
 */
template <typename T>
inline
typename DGtal::ModuloComputer<T>::UnsignedInteger 
DGtal::ModuloComputer<T>::cast( IntegerParamType i ) const
{
  Integer tmp = i;
  while ( tmp < 0 ) tmp += k;
  UnsignedInteger ip = (Integer) tmp;
  while ( ip >= k ) ip -= k;
  return ip;
}
 
    
/**
 * Less comparator modulo. Be careful, modulo comparisons have no
 * sense when the absolute difference of the values are around k / 2.
 *
 * @param i any value between 0 and [k] (excluded).  @param j any
 * value between 0 and [k] (excluded).  @return 'true' if [i] strictly
 * precedes [j] in a window 'floor([k]/2)'.  @see k
 */
template <typename T>
inline
bool 
DGtal::ModuloComputer<T>::less( UnsignedIntegerParamType i, UnsignedIntegerParamType j ) const
{
  Integer d = ( (T) j ) - ( (T) i );
  if ( d > 0 )
    return d < (T) ( k / 2 );
  else
    return (-d) >= (T) ( k / 2 );
}
 
 
/**
 * Performs j - i modulo, assuming less(i,j) is true.
 *
 * @param j any value between 0 and [k] (excluded).
 * @param i any value between 0 and [k] (excluded).
 * @return the value j - i, always positive. 
 */
template <typename T>
inline
typename DGtal::ModuloComputer<T>::UnsignedInteger 
DGtal::ModuloComputer<T>::posDiff( UnsignedIntegerParamType  j, UnsignedIntegerParamType i ) const
{
  return ( i <= j ) ? j - i : j + k - i;
}
 
 
 
/**
 * Writes/Displays the object on an output stream.
 * @param out the output stream where the object is written.
 */
template <typename T>
inline
void
DGtal::ModuloComputer<T>::selfDisplay ( std::ostream & out ) const
{
  out << "[ModuloComputer]";
}
 
/**
 * Checks the validity/consistency of the object.
 * @return 'true' if the object is valid, 'false' otherwise.
 */
template <typename T>
inline
bool
DGtal::ModuloComputer<T>::isValid() const
{
    return true;
}