/*
 * Copyright ConsenSys AG.
 *
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
package org.hyperledger.besu.util;

/** The Endian utils. */
public class EndianUtils {
  // next two methods adopted from:
  // https://github.com/bcgit/bc-java/blob/master/core/src/main/java/org/bouncycastle/util/Pack.java

  /**
   * Long to big endian.
   *
   * @param n the n
   * @return the byte [ ]
   */
  public static byte[] longToBigEndian(final long n) {
    final byte[] bs = new byte[8];
    intToBigEndian((int) (n >>> 32), bs, 0);
    intToBigEndian((int) (n & 0xffffffffL), bs, 4);
    return bs;
  }

  /**
   * Int to big endian.
   *
   * @param n the n
   * @param bs the bs
   * @param off the off
   */
  @SuppressWarnings("MethodInputParametersMustBeFinal")
  public static void intToBigEndian(final int n, final byte[] bs, int off) {
    bs[off] = (byte) (n >>> 24);
    bs[++off] = (byte) (n >>> 16);
    bs[++off] = (byte) (n >>> 8);
    bs[++off] = (byte) (n);
  }
}
