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- /* ====================================================================
- Licensed to the Apache Software Foundation (ASF) under one or more
- contributor license agreements. See the NOTICE file distributed with
- this work for additional information regarding copyright ownership.
- The ASF licenses this file to You under the Apache License, Version 2.0
- (the "License"); you may not use this file except in compliance with
- the License. You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- ==================================================================== */
-
- package org.apache.poi.util;
-
- /**
- * Utility classes for dealing with arrays.
- *
- * @author Glen Stampoultzis
- */
- public class ArrayUtil
- {
- /**
- * This is really a debugging version of <code>System.arraycopy()</code>.
- * Use it to provide better exception messages when copying arrays around.
- * For production use it's better to use the original for speed.
- */
- public static void arraycopy(byte[] src, int src_position, byte[] dst, int dst_position, int length)
- {
- if (src_position < 0)
- throw new IllegalArgumentException("src_position was less than 0. Actual value " + src_position);
- if (src_position >= src.length)
- throw new IllegalArgumentException( "src_position was greater than src array size. Tried to write starting at position " + src_position + " but the array length is " + src.length );
- if (src_position + length > src.length)
- throw new IllegalArgumentException("src_position + length would overrun the src array. Expected end at " + (src_position + length) + " actual end at " + src.length);
- if (dst_position < 0)
- throw new IllegalArgumentException("dst_position was less than 0. Actual value " + dst_position);
- if (dst_position >= dst.length)
- throw new IllegalArgumentException( "dst_position was greater than dst array size. Tried to write starting at position " + dst_position + " but the array length is " + dst.length );
- if (dst_position + length > dst.length)
- throw new IllegalArgumentException("dst_position + length would overrun the dst array. Expected end at " + (dst_position + length) + " actual end at " + dst.length);
-
- System.arraycopy( src, src_position, dst, dst_position, length);
- }
-
- /**
- * Moves a number of entries in an array to another point in the array,
- * shifting those inbetween as required.
- * @param array The array to alter
- * @param moveFrom The (0 based) index of the first entry to move
- * @param moveTo The (0 based) index of the positition to move to
- * @param numToMove The number of entries to move
- */
- public static void arrayMoveWithin(Object[] array, int moveFrom, int moveTo, int numToMove) {
- // If we're not asked to do anything, return now
- if(numToMove <= 0) { return; }
- if(moveFrom == moveTo) { return; }
-
- // Check that the values supplied are valid
- if(moveFrom < 0 || moveFrom >= array.length) {
- throw new IllegalArgumentException("The moveFrom must be a valid array index");
- }
- if(moveTo < 0 || moveTo >= array.length) {
- throw new IllegalArgumentException("The moveTo must be a valid array index");
- }
- if(moveFrom+numToMove > array.length) {
- throw new IllegalArgumentException("Asked to move more entries than the array has");
- }
- if(moveTo+numToMove > array.length) {
- throw new IllegalArgumentException("Asked to move to a position that doesn't have enough space");
- }
-
- // Grab the bit to move
- Object[] toMove = new Object[numToMove];
- System.arraycopy(array, moveFrom, toMove, 0, numToMove);
-
- // Grab the bit to be shifted
- Object[] toShift;
- int shiftTo;
- if(moveFrom > moveTo) {
- // Moving to an earlier point in the array
- // Grab everything between the two points
- toShift = new Object[(moveFrom-moveTo)];
- System.arraycopy(array, moveTo, toShift, 0, toShift.length);
- shiftTo = moveTo + numToMove;
- } else {
- // Moving to a later point in the array
- // Grab everything from after the toMove block, to the new point
- toShift = new Object[(moveTo-moveFrom)];
- System.arraycopy(array, moveFrom+numToMove, toShift, 0, toShift.length);
- shiftTo = moveFrom;
- }
-
- // Copy the moved block to its new location
- System.arraycopy(toMove, 0, array, moveTo, toMove.length);
-
- // And copy the shifted block to the shifted location
- System.arraycopy(toShift, 0, array, shiftTo, toShift.length);
-
-
- // We're done - array will now have everything moved as required
- }
- }
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