snakeindex< T > Class Template Reference

Indexing a 2D matrix with a snake pattern. More...

#include <snakeindex.h>

Collaboration diagram for snakeindex< T >:

List of all members.

Public Member Functions
	snakeindex (T const _columns, T const _length, bool forward=true)
	Pass in the number of columns and length of the matrix, configure the iterator forwards or backwards.
void	reset ()
	Reset the iterator.
boolc	operator! () const
	Is the iterator valid?
void	operator++ ()
	Increment the iterator.
void	pos (T &row, T &col) const
	The current position as a 2D indexed point.
void	pos (T &k2) const
	The current position as an index from the start.
Public Attributes
T const	rows
	The number of rows.
T const	columns
	The number of columns.
T const	length
	The length of the 2D matrix.

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Detailed Description

template<typename T = int>
class snakeindex< T >

Indexing a 2D matrix with a snake pattern.

Two combinations of itterating a 2D matrix are made.

To get the other two combinations, take a N by M matrix and consecutively label the elements from 0, then transpose it so it is now an M by N matrix.

Now construct a M by N snakeindex iterator and the other two combinations are realized by indexing on the transposed matrix.

Definition at line 22 of file snakeindex.h.

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Constructor & Destructor Documentation

template<typename T = int>

snakeindex< T >::snakeindex	(	T const	_columns,
		T const	_length,
		bool	forward = true
	)

Pass in the number of columns and length of the matrix, configure the iterator forwards or backwards.

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Member Function Documentation

template<typename T = int>

boolc snakeindex< T >::operator!

(

)

const [inline]

Is the iterator valid?

Definition at line 50 of file snakeindex.h.

References snakeindex< T >::length.

    { return (current>=0)&&(current<length); }

template<typename T = int>

void snakeindex< T >::operator++

(

)

[inline]

Increment the iterator.

Definition at line 53 of file snakeindex.h.

    { current += dcurrent; }

template<typename T >

void snakeindex< T >::pos

(

T &

k2

)

const [inline]

The current position as an index from the start.

Definition at line 67 of file snakeindex.h.

References snakeindex< T >::columns, and snakeindex< T >::pos().

{
  T row;
  T col;
  pos(row,col);
  k2 = row*columns+col;
}

template<typename T >

void snakeindex< T >::pos	(	T &	row,
		T &	col
	)			const [inline]

The current position as a 2D indexed point.

Definition at line 76 of file snakeindex.h.

References snakeindex< T >::columns.

Referenced by snakeindex< T >::pos(), snakeindextest::test01(), snakeindextest::test02(), and snakeindextest::test03().

{
  row = (current - (current % columns))/columns;
  col = current-row*columns;
  if ((row % 2)==1)
    col = columns-1-col;
}

template<typename T >

void snakeindex< T >::reset

(

)

[inline]

Reset the iterator.

Definition at line 85 of file snakeindex.h.

References snakeindex< T >::length.

Referenced by snakeindextest::test01(), snakeindextest::test02(), and snakeindextest::test03().

{
  if (dcurrent>0)
    current=0;
  else
    current=length-1;
}

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Member Data Documentation

template<typename T = int>

T const snakeindex< T >::columns

The number of columns.

Definition at line 33 of file snakeindex.h.

Referenced by snakeindex< T >::pos().

template<typename T = int>

T const snakeindex< T >::length

The length of the 2D matrix.

Definition at line 35 of file snakeindex.h.

Referenced by snakeindex< T >::operator!(), and snakeindex< T >::reset().

template<typename T = int>

T const snakeindex< T >::rows

The number of rows.

Definition at line 31 of file snakeindex.h.

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

• sortsimple/snakeindex.h