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/*
* Copyright (C) 2022 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.net.module.util;
import android.annotation.NonNull;
/**
* Byte utility functions.
* @hide
*/
public class ByteUtils {
/**
* Returns the index of the first appearance of the value {@code target} in {@code array}.
*
* @param array an array of {@code byte} values, possibly empty
* @param target a primitive {@code byte} value
* @return the least index {@code i} for which {@code array[i] == target}, or {@code -1} if no
* such index exists.
*/
public static int indexOf(@NonNull byte[] array, byte target) {
return indexOf(array, target, 0, array.length);
}
private static int indexOf(byte[] array, byte target, int start, int end) {
for (int i = start; i < end; i++) {
if (array[i] == target) {
return i;
}
}
return -1;
}
/**
* Returns the values from each provided array combined into a single array. For example, {@code
* concat(new byte[] {a, b}, new byte[] {}, new byte[] {c}} returns the array {@code {a, b, c}}.
*
* @param arrays zero or more {@code byte} arrays
* @return a single array containing all the values from the source arrays, in order
*/
public static byte[] concat(@NonNull byte[]... arrays) {
int length = 0;
for (byte[] array : arrays) {
length += array.length;
}
byte[] result = new byte[length];
int pos = 0;
for (byte[] array : arrays) {
System.arraycopy(array, 0, result, pos, array.length);
pos += array.length;
}
return result;
}
}
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