| /* |
| * Copyright (C) 2021 The Android Open Source Project |
| * |
| * Licensed 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 android.util; |
| |
| /** |
| * SparseDoubleArrays map integers to doubles. Unlike a normal array of doubles, |
| * there can be gaps in the indices. It is intended to be more memory efficient |
| * than using a HashMap to map Integers to Doubles, both because it avoids |
| * auto-boxing keys and values and its data structure doesn't rely on an extra entry object |
| * for each mapping. |
| * |
| * <p>Note that this container keeps its mappings in an array data structure, |
| * using a binary search to find keys. The implementation is not intended to be appropriate for |
| * data structures |
| * that may contain large numbers of items. It is generally slower than a traditional |
| * HashMap, since lookups require a binary search and adds and removes require inserting |
| * and deleting entries in the array. For containers holding up to hundreds of items, |
| * the performance difference is not significant, less than 50%.</p> |
| * |
| * <p>It is possible to iterate over the items in this container using |
| * {@link #keyAt(int)} and {@link #valueAt(int)}. Iterating over the keys using |
| * <code>keyAt(int)</code> with ascending values of the index will return the |
| * keys in ascending order, or the values corresponding to the keys in ascending |
| * order in the case of <code>valueAt(int)</code>.</p> |
| * |
| * @see SparseLongArray |
| * |
| * @hide |
| */ |
| @android.ravenwood.annotation.RavenwoodKeepWholeClass |
| public class SparseDoubleArray implements Cloneable { |
| /** |
| * The int->double map, but storing the doubles as longs using |
| * {@link Double#doubleToRawLongBits(double)}. |
| */ |
| private SparseLongArray mValues; |
| |
| /** Creates a new SparseDoubleArray containing no mappings. */ |
| public SparseDoubleArray() { |
| this(0); |
| } |
| |
| /** |
| * Creates a new SparseDoubleArray, containing no mappings, that will not |
| * require any additional memory allocation to store the specified |
| * number of mappings. If you supply an initial capacity of 0, the |
| * sparse array will be initialized with a light-weight representation |
| * not requiring any additional array allocations. |
| */ |
| public SparseDoubleArray(int initialCapacity) { |
| mValues = new SparseLongArray(initialCapacity); |
| } |
| |
| @Override |
| public SparseDoubleArray clone() { |
| SparseDoubleArray clone = null; |
| try { |
| clone = (SparseDoubleArray) super.clone(); |
| clone.mValues = mValues.clone(); |
| } catch (CloneNotSupportedException cnse) { |
| /* ignore */ |
| } |
| return clone; |
| } |
| |
| /** |
| * Gets the double mapped from the specified key, or <code>0</code> |
| * if no such mapping has been made. |
| */ |
| public double get(int key) { |
| return get(key, 0); |
| } |
| |
| /** |
| * Gets the double mapped from the specified key, or the specified value |
| * if no such mapping has been made. |
| */ |
| public double get(int key, double valueIfKeyNotFound) { |
| final int index = mValues.indexOfKey(key); |
| if (index < 0) { |
| return valueIfKeyNotFound; |
| } |
| return valueAt(index); |
| } |
| |
| /** |
| * Adds a mapping from the specified key to the specified value, |
| * replacing the previous mapping from the specified key if there |
| * was one. |
| */ |
| public void put(int key, double value) { |
| mValues.put(key, Double.doubleToRawLongBits(value)); |
| } |
| |
| /** |
| * Adds a mapping from the specified key to the specified value, |
| * <b>adding</b> its value to the previous mapping from the specified key if there |
| * was one. |
| * |
| * <p>This differs from {@link #put} because instead of replacing any previous value, it adds |
| * (in the numerical sense) to it. |
| */ |
| public void incrementValue(int key, double summand) { |
| final double oldValue = get(key); |
| put(key, oldValue + summand); |
| } |
| |
| /** Returns the number of key-value mappings that this SparseDoubleArray currently stores. */ |
| public int size() { |
| return mValues.size(); |
| } |
| |
| /** |
| * Returns the index for which {@link #keyAt} would return the |
| * specified key, or a negative number if the specified |
| * key is not mapped. |
| */ |
| public int indexOfKey(int key) { |
| return mValues.indexOfKey(key); |
| } |
| |
| /** |
| * Given an index in the range <code>0...size()-1</code>, returns |
| * the key from the <code>index</code>th key-value mapping that this |
| * SparseDoubleArray stores. |
| * |
| * @see SparseLongArray#keyAt(int) |
| */ |
| public int keyAt(int index) { |
| return mValues.keyAt(index); |
| } |
| |
| /** |
| * Given an index in the range <code>0...size()-1</code>, returns |
| * the value from the <code>index</code>th key-value mapping that this |
| * SparseDoubleArray stores. |
| * |
| * @see SparseLongArray#valueAt(int) |
| */ |
| public double valueAt(int index) { |
| return Double.longBitsToDouble(mValues.valueAt(index)); |
| } |
| |
| /** |
| * Given an index in the range <code>0...size()-1</code>, sets a new |
| * value for the <code>index</code>th key-value mapping that this |
| * SparseDoubleArray stores. |
| * |
| * <p>For indices outside of the range <code>0...size()-1</code>, the behavior is undefined for |
| * apps targeting {@link android.os.Build.VERSION_CODES#P} and earlier, and an |
| * {@link ArrayIndexOutOfBoundsException} is thrown for apps targeting |
| * {@link android.os.Build.VERSION_CODES#Q} and later.</p> |
| */ |
| public void setValueAt(int index, double value) { |
| mValues.setValueAt(index, Double.doubleToRawLongBits(value)); |
| } |
| |
| /** |
| * Removes the mapping at the given index. |
| */ |
| public void removeAt(int index) { |
| mValues.removeAt(index); |
| } |
| |
| /** |
| * Removes the mapping from the specified key, if there was any. |
| */ |
| public void delete(int key) { |
| mValues.delete(key); |
| } |
| |
| /** |
| * Removes all key-value mappings from this SparseDoubleArray. |
| */ |
| public void clear() { |
| mValues.clear(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p>This implementation composes a string by iterating over its mappings. |
| */ |
| @Override |
| public String toString() { |
| if (size() <= 0) { |
| return "{}"; |
| } |
| |
| StringBuilder buffer = new StringBuilder(size() * 34); |
| buffer.append('{'); |
| for (int i = 0; i < size(); i++) { |
| if (i > 0) { |
| buffer.append(", "); |
| } |
| int key = keyAt(i); |
| buffer.append(key); |
| buffer.append('='); |
| double value = valueAt(i); |
| buffer.append(value); |
| } |
| buffer.append('}'); |
| return buffer.toString(); |
| } |
| } |