Delete ByteStringUtils: it is no longer used

/*

 * Copyright (C) 2017 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;

import libcore.util.HexEncoding;

/**

 * A utility class for common byte array to hex string operations and vise versa.

 *

 * @hide

 */

public final class ByteStringUtils {

    private ByteStringUtils() {

    /* hide constructor */

    }

    /**

     * Returns the hex encoded string representation of bytes.

     * @param bytes Byte array to encode.

     * @return Hex encoded string representation of bytes.

     */

    public static String toHexString(byte[] bytes) {

        if (bytes == null || bytes.length == 0 || bytes.length % 2 != 0) {

            return null;

        }

        return HexEncoding.encodeToString(bytes, true /* upperCase */);

    }

    /**

     * Returns the decoded byte array representation of str.

     * @param str Hex encoded string to decode.

     * @return Decoded byte array representation of str.

     */

    public static byte[] fromHexToByteArray(String str) {

        if (str == null || str.length() == 0 || str.length() % 2 != 0) {

            return null;

        }

        return HexEncoding.decode(str, false /* allowSingleChar */);

    }

}