content: /*
   *  Copyright Beijing 58 Information Technology Co.,Ltd.
   *
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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.bj58.spat.gaea.protocol.utility;
  
  /**
   * ByteConverter
   *
   * @author Service Platform Architecture Team (spat@58.com)
   */
  public class ByteConverter {
  
      /**
       * byte array to int (little endian)
       * @param buf
       * @return
       */
      public static int bytesToIntLittleEndian(byte buf[]) {
          return buf[0] & 0xff
                  | ((buf[1] << 8) & 0xff00)
                  | ((buf[2] << 16) & 0xff0000)
                  | ((buf[3] << 24) & 0xff000000);
      }
  
      /**
       * int to byte array (little endian)
       * @param n
       * @return
       */
      public static byte[] intToBytesLittleEndian(int n) {
          byte[] buf = new byte[4];
          buf[0] = (byte) (0xff & n);
          buf[1] = (byte) ((0xff00 & n) >> 8);
          buf[2] = (byte) ((0xff0000 & n) >> 16);
          buf[3] = (byte) ((0xff000000 & n) >> 24);
          return buf;
      }
  
      /**
       * byte array to int (big endian)
       * @param buf
       * @return
       */
      public static int bytesToIntBigEndian(byte[] buf) {
          return ((buf[0] << 24) & 0xff000000)
                  | ((buf[1] << 16) & 0xff0000)
                  | ((buf[2] << 8) & 0xff00)
                  | (buf[3] & 0xff);
      }
  
      /**
       * int to byte array (big endian)
       * @param n
       * @return
       */
      public static byte[] intToBytesBigEndian(int n) {
          byte[] buf = new byte[4];
          buf[0] = (byte) ((0xff000000 & n) >> 24);
          buf[1] = (byte) ((0xff0000 & n) >> 16);
          buf[2] = (byte) ((0xff00 & n) >> 8);
          buf[3] = (byte) (0xff & n);
          return buf;
      }
      
     
      public static int bytesToIntLittleEndian(byte buf[], int offset) {
          return buf[offset] & 0xff
                  | ((buf[offset + 1] << 8) & 0xff00)
                  | ((buf[offset + 2] << 16) & 0xff0000)
                  | ((buf[offset + 3] << 24) & 0xff000000);
      }
  
      public static int bytesToIntBigEndian(byte[] buf, int offset) {
          return ((buf[offset] << 24) & 0xff000000)
                  | ((buf[offset + 1] << 16) & 0xff0000)
                  | ((buf[offset + 2] << 8) & 0xff00)
                  | (buf[offset + 3] & 0xff);
      }
  }