Helper method for when moving stuff about in an array, plus test
git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@418607 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Nick Burch
parent
4864da55d5
commit
19894ffa53
@ -47,5 +47,61 @@ public class ArrayUtil
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System.arraycopy( src, src_position, dst, dst_position, length);
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}
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/**
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* Moves a number of entries in an array to another point in the array,
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* shifting those inbetween as required.
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* @param array The array to alter
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* @param moveFrom The (0 based) index of the first entry to move
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* @param moveTo The (0 based) index of the positition to move to
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* @param numToMove The number of entries to move
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*/
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public static void arrayMoveWithin(Object[] array, int moveFrom, int moveTo, int numToMove) {
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// If we're not asked to do anything, return now
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if(numToMove <= 0) { return; }
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if(moveFrom == moveTo) { return; }
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// Check that the values supplied are valid
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if(moveFrom < 0 || moveFrom >= array.length) {
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throw new IllegalArgumentException("The moveFrom must be a valid array index");
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}
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if(moveTo < 0 || moveTo >= array.length) {
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throw new IllegalArgumentException("The moveTo must be a valid array index");
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}
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if(moveFrom+numToMove > array.length) {
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throw new IllegalArgumentException("Asked to move more entries than the array has");
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}
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if(moveTo+numToMove > array.length) {
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throw new IllegalArgumentException("Asked to move to a position that doesn't have enough space");
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}
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// Grab the bit to move
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Object[] toMove = new Object[numToMove];
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System.arraycopy(array, moveFrom, toMove, 0, numToMove);
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// Grab the bit to be shifted
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Object[] toShift;
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int shiftTo;
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if(moveFrom > moveTo) {
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// Moving to an earlier point in the array
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// Grab everything between the two points
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toShift = new Object[(moveFrom-moveTo)];
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System.arraycopy(array, moveTo, toShift, 0, toShift.length);
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shiftTo = moveTo + numToMove;
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} else {
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// Moving to a later point in the array
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// Grab everything from after the toMove block, to the new point
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toShift = new Object[(moveTo-moveFrom)];
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System.arraycopy(array, moveFrom+numToMove, toShift, 0, toShift.length);
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shiftTo = moveFrom;
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}
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// Copy the moved block to its new location
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System.arraycopy(toMove, 0, array, moveTo, toMove.length);
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// And copy the shifted block to the shifted location
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System.arraycopy(toShift, 0, array, shiftTo, toShift.length);
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// We're done - array will now have everything moved as required
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}
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}
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291
src/testcases/org/apache/poi/util/TestArrayUtil.java
Normal file
291
src/testcases/org/apache/poi/util/TestArrayUtil.java
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@ -0,0 +1,291 @@
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/* ====================================================================
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Copyright 2002-2004 Apache Software Foundation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.util;
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import junit.framework.*;
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/**
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* Unit test for ArrayUtil
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*
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* @author Nick Burch
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*/
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public class TestArrayUtil extends TestCase
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{
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/**
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* Test to ensure that our own arraycopy behaves as it should do
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*/
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public void testarraycopy() {
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byte[] bytes = new byte[] { 0x01, 0x02, 0x03, 0x04 };
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// Test copy whole thing
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byte[] dest = new byte[4];
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ArrayUtil.arraycopy(bytes, 0, dest, 0, 4);
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assertEquals(dest.length, bytes.length);
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for(int i=0; i<dest.length; i++) {
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assertEquals(bytes[i], dest[i]);
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}
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// ToDo - test exceptions are as expected
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}
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/**
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* Helper for testArrayMoveWithin
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*/
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private Integer[] getIntsList() {
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return new Integer[] {
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new Integer(0),
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new Integer(1),
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new Integer(2),
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new Integer(3),
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new Integer(4),
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new Integer(5),
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new Integer(6),
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new Integer(7),
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new Integer(8),
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new Integer(9)
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};
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}
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/**
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* Test to ensure that arrayMoveWithin works as expected
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*/
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public void testArrayMoveWithin() {
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Integer[] ints = getIntsList();
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(2), ints[2]);
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assertEquals(new Integer(3), ints[3]);
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assertEquals(new Integer(4), ints[4]);
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assertEquals(new Integer(5), ints[5]);
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assertEquals(new Integer(6), ints[6]);
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assertEquals(new Integer(7), ints[7]);
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assertEquals(new Integer(8), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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//
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// Moving to a later point in the array
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//
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// Shift 1 back
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 4, 8, 1);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(2), ints[2]);
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assertEquals(new Integer(3), ints[3]);
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assertEquals(new Integer(5), ints[4]);
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assertEquals(new Integer(6), ints[5]);
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assertEquals(new Integer(7), ints[6]);
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assertEquals(new Integer(8), ints[7]);
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assertEquals(new Integer(4), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift front 1 back
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 0, 7, 1);
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assertEquals(new Integer(1), ints[0]);
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assertEquals(new Integer(2), ints[1]);
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assertEquals(new Integer(3), ints[2]);
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assertEquals(new Integer(4), ints[3]);
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assertEquals(new Integer(5), ints[4]);
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assertEquals(new Integer(6), ints[5]);
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assertEquals(new Integer(7), ints[6]);
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assertEquals(new Integer(0), ints[7]);
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assertEquals(new Integer(8), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift 1 to end
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 4, 9, 1);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(2), ints[2]);
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assertEquals(new Integer(3), ints[3]);
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assertEquals(new Integer(5), ints[4]);
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assertEquals(new Integer(6), ints[5]);
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assertEquals(new Integer(7), ints[6]);
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assertEquals(new Integer(8), ints[7]);
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assertEquals(new Integer(9), ints[8]);
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assertEquals(new Integer(4), ints[9]);
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//
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// Moving to an earlier point in the array
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//
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// Shift 1 forward
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 8, 3, 1);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(2), ints[2]);
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assertEquals(new Integer(8), ints[3]);
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assertEquals(new Integer(3), ints[4]);
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assertEquals(new Integer(4), ints[5]);
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assertEquals(new Integer(5), ints[6]);
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assertEquals(new Integer(6), ints[7]);
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assertEquals(new Integer(7), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift end 1 forward
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 9, 2, 1);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(9), ints[2]);
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assertEquals(new Integer(2), ints[3]);
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assertEquals(new Integer(3), ints[4]);
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assertEquals(new Integer(4), ints[5]);
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assertEquals(new Integer(5), ints[6]);
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assertEquals(new Integer(6), ints[7]);
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assertEquals(new Integer(7), ints[8]);
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assertEquals(new Integer(8), ints[9]);
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// Shift 1 to front
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 5, 0, 1);
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assertEquals(new Integer(5), ints[0]);
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assertEquals(new Integer(0), ints[1]);
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assertEquals(new Integer(1), ints[2]);
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assertEquals(new Integer(2), ints[3]);
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assertEquals(new Integer(3), ints[4]);
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assertEquals(new Integer(4), ints[5]);
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assertEquals(new Integer(6), ints[6]);
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assertEquals(new Integer(7), ints[7]);
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assertEquals(new Integer(8), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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//
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// Moving many to a later point in the array
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//
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// Shift 3 back
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 2, 6, 3);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(5), ints[2]);
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assertEquals(new Integer(6), ints[3]);
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assertEquals(new Integer(7), ints[4]);
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assertEquals(new Integer(8), ints[5]);
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assertEquals(new Integer(2), ints[6]);
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assertEquals(new Integer(3), ints[7]);
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assertEquals(new Integer(4), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift 3 to back
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 2, 7, 3);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(5), ints[2]);
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assertEquals(new Integer(6), ints[3]);
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assertEquals(new Integer(7), ints[4]);
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assertEquals(new Integer(8), ints[5]);
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assertEquals(new Integer(9), ints[6]);
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assertEquals(new Integer(2), ints[7]);
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assertEquals(new Integer(3), ints[8]);
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assertEquals(new Integer(4), ints[9]);
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// Shift from 3 front
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 0, 5, 3);
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assertEquals(new Integer(3), ints[0]);
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assertEquals(new Integer(4), ints[1]);
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assertEquals(new Integer(5), ints[2]);
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assertEquals(new Integer(6), ints[3]);
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assertEquals(new Integer(7), ints[4]);
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assertEquals(new Integer(0), ints[5]);
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assertEquals(new Integer(1), ints[6]);
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assertEquals(new Integer(2), ints[7]);
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assertEquals(new Integer(8), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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//
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// Moving many to an earlier point in the array
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//
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// Shift 3 forward
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 6, 2, 3);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(6), ints[2]);
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assertEquals(new Integer(7), ints[3]);
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assertEquals(new Integer(8), ints[4]);
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assertEquals(new Integer(2), ints[5]);
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assertEquals(new Integer(3), ints[6]);
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assertEquals(new Integer(4), ints[7]);
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assertEquals(new Integer(5), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift 3 to front
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 6, 0, 3);
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assertEquals(new Integer(6), ints[0]);
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assertEquals(new Integer(7), ints[1]);
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assertEquals(new Integer(8), ints[2]);
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assertEquals(new Integer(0), ints[3]);
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assertEquals(new Integer(1), ints[4]);
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assertEquals(new Integer(2), ints[5]);
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assertEquals(new Integer(3), ints[6]);
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assertEquals(new Integer(4), ints[7]);
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assertEquals(new Integer(5), ints[8]);
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assertEquals(new Integer(9), ints[9]);
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// Shift from 3 back
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 7, 3, 3);
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assertEquals(new Integer(0), ints[0]);
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assertEquals(new Integer(1), ints[1]);
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assertEquals(new Integer(2), ints[2]);
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assertEquals(new Integer(7), ints[3]);
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assertEquals(new Integer(8), ints[4]);
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assertEquals(new Integer(9), ints[5]);
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assertEquals(new Integer(3), ints[6]);
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assertEquals(new Integer(4), ints[7]);
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assertEquals(new Integer(5), ints[8]);
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assertEquals(new Integer(6), ints[9]);
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// Check can't shift more than we have
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try {
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 7, 3, 5);
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fail();
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} catch(IllegalArgumentException e) {
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// Good, we don't have 5 from 7 onwards
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}
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// Check can't shift where would overshoot
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try {
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ints = getIntsList();
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ArrayUtil.arrayMoveWithin(ints, 2, 7, 5);
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fail();
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} catch(IllegalArgumentException e) {
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// Good, we can't fit 5 in starting at 7
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}
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}
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}
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