// Copyright (c) 2013, Facebook, Inc. All rights reserved.
/**
* 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 com.facebook.hive.orc;
import org.apache.hadoop.hive.ql.io.slice.SizeOf;
import org.apache.hadoop.hive.ql.io.slice.Slice;
import org.apache.hadoop.hive.ql.io.slice.Slices;
/**
* Dynamic int array that uses primitive types and chunks to avoid copying
* large number of integers when it resizes.
*
* The motivation for this class is memory optimization, i.e. space efficient
* storage of potentially huge arrays without good a-priori size guesses.
*
* The API of this class is between a primitive array and a AbstractList. It's
* not a Collection implementation because it handles primitive types, but the
* API could be extended to support iterators and the like.
*
* NOTE: Like standard Collection implementations/arrays, this class is not
* synchronized.
*/
final class DynamicIntArray {
static final int DEFAULT_SIZE = SizeOf.SIZE_OF_INT * 8 * 1024;
private Slice data; // the real data
private int length = 0; // max set element index +1
public DynamicIntArray() {
this(DEFAULT_SIZE);
}
public DynamicIntArray(int size) {
data = Slices.allocate(size);
}
/**
* Ensure that the given index is valid.
*/
private void grow(int index) {
if ((index * SizeOf.SIZE_OF_INT) + (SizeOf.SIZE_OF_INT - 1) >= data.length()) {
int newSize = Math.max((index * SizeOf.SIZE_OF_INT) + DEFAULT_SIZE, 2 * data.length());
Slice newSlice = Slices.allocate(newSize);
newSlice.setBytes(0, data);
data = newSlice;
}
}
public int get(int index) {
if (index >= length) {
throw new IndexOutOfBoundsException("Index " + index +
" is outside of 0.." +
(length - 1));
}
return data.getInt(index * SizeOf.SIZE_OF_INT);
}
public void set(int index, int value) {
grow(index);
if (index >= length) {
length = index + 1;
}
data.setInt(index * SizeOf.SIZE_OF_INT, value);
}
public void increment(int index, int value) {
grow(index);
if (index >= length) {
length = index + 1;
}
data.setInt(index * SizeOf.SIZE_OF_INT, data.getInt(index * SizeOf.SIZE_OF_INT) + value);
}
public void add(int value) {
grow(length);
data.setInt(length * SizeOf.SIZE_OF_INT, value);
length += 1;
}
public int size() {
return length;
}
public void clear() {
length = 0;
data = Slices.allocate(DEFAULT_SIZE);
}
@Override
public String toString() {
int i;
StringBuilder sb = new StringBuilder(length * 4);
sb.append('{');
int l = length - 1;
for (i=0; i<l; i++) {
sb.append(get(i));
sb.append(',');
}
sb.append(get(i));
sb.append('}');
return sb.toString();
}
public int getSizeInBytes() {
return data.length();
}
}