001/*-
002 *******************************************************************************
003 * Copyright (c) 2011, 2016 Diamond Light Source Ltd.
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the Eclipse Public License v1.0
006 * which accompanies this distribution, and is available at
007 * http://www.eclipse.org/legal/epl-v10.html
008 *
009 * Contributors:
010 *    Peter Chang - initial API and implementation and/or initial documentation
011 *******************************************************************************/
012
013package org.eclipse.january.dataset;
014
015import java.util.Arrays;
016
017
018/**
019 * Class to run over contiguous datasets and keep track of position. Note this is slower than ContiguousIterator
020 */
021public class ContiguousIteratorWithPosition extends IndexIterator {
022        final private int[] shape;
023        final private int endrank; // last dimensions index
024        final private int imax; // maximum index in array
025        final private int istep; // step over items
026        final private int[] pos; // position in dataset
027
028        /**
029         * Constructor for an iterator over the items of a dataset that are
030         * within the dimensions
031         *
032         * @param shape
033         * @param length of entire data array
034         */
035        public ContiguousIteratorWithPosition(final int[] shape, final int length) {
036                this(shape, length, 1);
037        }
038
039        /**
040         * Constructor for an iterator over the items of a dataset that are
041         * within the dimensions
042         *
043         * @param shape
044         * @param length of entire data array
045         * @param isize number of elements in an item
046         */
047        public ContiguousIteratorWithPosition(final int[] shape, final int length, final int isize) {
048                this.shape = shape;
049                endrank = this.shape.length - 1;
050                istep = isize;
051                if (shape.length == 0) {
052                        pos = new int[0];
053                } else {
054                        pos = new int[endrank + 1];
055                        pos[endrank] = -1;
056                }
057                index = -isize;
058                imax = length * isize;
059        }
060
061        @Override
062        public boolean hasNext() {
063                // now move on one position
064                int j = endrank;
065                for (; j >= 0; j--) {
066                        pos[j]++;
067                        if (pos[j] >= shape[j]) {
068                                pos[j] = 0;
069                        } else {
070                                break;
071                        }
072                }
073                if (j == -1 && endrank >= 0) {
074                        return false;
075                }
076
077                index += istep;
078                return index < imax;
079        }
080
081        /**
082         * @return position indices (nb not a copy)
083         */
084        @Override
085        public int[] getPos() {
086                return pos;
087        }
088
089        @Override
090        public void reset() {
091                if (shape.length > 0) {
092                        Arrays.fill(pos, 0);
093                        pos[endrank] = -1;
094                }
095                index = -istep;
096        }
097
098        @Override
099        public int[] getShape() {
100                return shape;
101        }
102}