Suwayomi-Server/AndroidCompat/src/main/java/com/android/internal/util/GrowingArrayUtils.java

/*
 * Copyright (C) 2014 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 com.android.internal.util;

public final class GrowingArrayUtils {

    public static <T> T[] append(T[] array, int currentSize, T element) {
        assert currentSize <= array.length;

        if (currentSize + 1 > array.length) {
            @SuppressWarnings("unchecked")
            T[] newArray = ArrayUtils.newUnpaddedArray(
                    (Class<T>) array.getClass().getComponentType(), growSize(currentSize));
            System.arraycopy(array, 0, newArray, 0, currentSize);
            array = newArray;
        }
        array[currentSize] = element;
        return array;
    }

    public static int[] append(int[] array, int currentSize, int element) {
        assert currentSize <= array.length;

        if (currentSize + 1 > array.length) {
            int[] newArray = ArrayUtils.newUnpaddedIntArray(growSize(currentSize));
            System.arraycopy(array, 0, newArray, 0, currentSize);
            array = newArray;
        }
        array[currentSize] = element;
        return array;
    }

    public static long[] append(long[] array, int currentSize, long element) {
        assert currentSize <= array.length;

        if (currentSize + 1 > array.length) {
            long[] newArray = ArrayUtils.newUnpaddedLongArray(growSize(currentSize));
            System.arraycopy(array, 0, newArray, 0, currentSize);
            array = newArray;
        }
        array[currentSize] = element;
        return array;
    }

    public static boolean[] append(boolean[] array, int currentSize, boolean element) {
        assert currentSize <= array.length;

        if (currentSize + 1 > array.length) {
            boolean[] newArray = ArrayUtils.newUnpaddedBooleanArray(growSize(currentSize));
            System.arraycopy(array, 0, newArray, 0, currentSize);
            array = newArray;
        }
        array[currentSize] = element;
        return array;
    }

    public static float[] append(float[] array, int currentSize, float element) {
        assert currentSize <= array.length;

        if (currentSize + 1 > array.length) {
            float[] newArray = ArrayUtils.newUnpaddedFloatArray(growSize(currentSize));
            System.arraycopy(array, 0, newArray, 0, currentSize);
            array = newArray;
        }
        array[currentSize] = element;
        return array;
    }

    public static <T> T[] insert(T[] array, int currentSize, int index, T element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize - index);
            array[index] = element;
            return array;
        }

        @SuppressWarnings("unchecked")
        T[] newArray = ArrayUtils.newUnpaddedArray((Class<T>)array.getClass().getComponentType(),
                growSize(currentSize));
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length - index);
        return newArray;
    }

    public static int[] insert(int[] array, int currentSize, int index, int element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize - index);
            array[index] = element;
            return array;
        }

        int[] newArray = ArrayUtils.newUnpaddedIntArray(growSize(currentSize));
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length - index);
        return newArray;
    }

    public static long[] insert(long[] array, int currentSize, int index, long element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize - index);
            array[index] = element;
            return array;
        }

        long[] newArray = ArrayUtils.newUnpaddedLongArray(growSize(currentSize));
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length - index);
        return newArray;
    }

    public static boolean[] insert(boolean[] array, int currentSize, int index, boolean element) {
        assert currentSize <= array.length;

        if (currentSize + 1 <= array.length) {
            System.arraycopy(array, index, array, index + 1, currentSize - index);
            array[index] = element;
            return array;
        }

        boolean[] newArray = ArrayUtils.newUnpaddedBooleanArray(growSize(currentSize));
        System.arraycopy(array, 0, newArray, 0, index);
        newArray[index] = element;
        System.arraycopy(array, index, newArray, index + 1, array.length - index);
        return newArray;
    }

    public static int growSize(int currentSize) {
        return currentSize <= 4 ? 8 : currentSize * 2;
    }

    // Uninstantiable
    private GrowingArrayUtils() {}
}