src/com/android/providers/media/util/Memory.java

/*
 * Copyright (C) 2019 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.providers.media.util;

import java.nio.ByteOrder;

public class Memory {
    public static int peekInt(byte[] src, int offset, ByteOrder order) {
        if (order == ByteOrder.BIG_ENDIAN) {
            return (((src[offset++] & 0xff) << 24) |
                    ((src[offset++] & 0xff) << 16) |
                    ((src[offset++] & 0xff) <<  8) |
                    ((src[offset  ] & 0xff) <<  0));
        } else {
            return (((src[offset++] & 0xff) <<  0) |
                    ((src[offset++] & 0xff) <<  8) |
                    ((src[offset++] & 0xff) << 16) |
                    ((src[offset  ] & 0xff) << 24));
        }
    }

    public static void pokeInt(byte[] dst, int offset, int value, ByteOrder order) {
        if (order == ByteOrder.BIG_ENDIAN) {
            dst[offset++] = (byte) ((value >> 24) & 0xff);
            dst[offset++] = (byte) ((value >> 16) & 0xff);
            dst[offset++] = (byte) ((value >>  8) & 0xff);
            dst[offset  ] = (byte) ((value >>  0) & 0xff);
        } else {
            dst[offset++] = (byte) ((value >>  0) & 0xff);
            dst[offset++] = (byte) ((value >>  8) & 0xff);
            dst[offset++] = (byte) ((value >> 16) & 0xff);
            dst[offset  ] = (byte) ((value >> 24) & 0xff);
        }
    }
}