| /* |
| * 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.sysds.runtime.compress.utils; |
| |
| import java.util.Arrays; |
| |
| /** |
| * This class provides a memory-efficient replacement for {@code ArrayList<Integer>} for restricted use cases. |
| */ |
| public class IntArrayList { |
| private static final int INIT_CAPACITY = 4; |
| private static final int RESIZE_FACTOR = 2; |
| |
| private int[] _data = null; |
| private int _size; |
| private int _val0; |
| |
| public IntArrayList() { |
| _data = null; |
| _size = 0; |
| } |
| |
| public IntArrayList(int value) { |
| this(); |
| appendValue(value); |
| } |
| |
| public IntArrayList(int[] values){ |
| _data = values; |
| _size = values.length; |
| } |
| |
| public int size() { |
| return _size; |
| } |
| |
| public void appendValue(int value) { |
| // embedded value (no array allocation) |
| if(_size == 0) { |
| _val0 = value; |
| _size = 1; |
| return; |
| } |
| |
| // allocate or resize array if necessary |
| if(_data == null) { |
| _data = new int[INIT_CAPACITY]; |
| _data[0] = _val0; |
| } |
| else if(_size + 1 >= _data.length) { |
| resize(); |
| } |
| |
| // append value |
| _data[_size] = value; |
| _size++; |
| } |
| |
| /** |
| * Returns the underlying array of offsets. Note that this array might be physically larger than the actual length |
| * of the offset lists. Use size() to obtain the actual length. |
| * |
| * @return integer array of offsets, the physical array length may be larger than the length of the offset list |
| */ |
| public int[] extractValues() { |
| if(_size == 1) |
| return new int[] {_val0}; |
| else |
| return _data; |
| } |
| |
| public int[] extractValues(boolean trim) { |
| int[] ret = extractValues(); |
| return (trim && _size < ret.length) ? Arrays.copyOfRange(ret, 0, _size) : ret; |
| } |
| |
| private void resize() { |
| // check for integer overflow on resize |
| if(_data.length > Integer.MAX_VALUE / RESIZE_FACTOR) |
| throw new RuntimeException("IntArrayList resize leads to integer overflow: size=" + _size); |
| |
| // resize data array and copy existing contents |
| _data = Arrays.copyOf(_data, _data.length * RESIZE_FACTOR); |
| } |
| |
| @Override |
| public String toString(){ |
| StringBuilder sb = new StringBuilder(); |
| sb.append("IntArrayList "); |
| sb.append("size: " + _size); |
| if(_size == 1){ |
| sb.append(" [" + _val0+ "] "); |
| } else{ |
| sb.append(" ["); |
| for(int i = 0; i < _size-1; i++){ |
| sb.append(_data[i] + ", "); |
| } |
| sb.append(_data[_data.length-1]+"] "); |
| } |
| return sb.toString(); |
| } |
| } |