content: /*
   *  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.alimama.mdrill.utils.zip;
  
  import static com.alimama.mdrill.utils.zip.ZipConstants.BYTE_MASK;
  import static com.alimama.mdrill.utils.zip.ZipConstants.WORD;
  
  /**
   * Utility class that represents a four byte integer with conversion
   * rules for the big endian byte order of ZIP files.
   *
   */
  public final class ZipLong implements Cloneable {
  
      //private static final int BYTE_BIT_SIZE = 8;
  
      private static final int BYTE_1 = 1;
      private static final int BYTE_1_MASK = 0xFF00;
      private static final int BYTE_1_SHIFT = 8;
  
      private static final int BYTE_2 = 2;
      private static final int BYTE_2_MASK = 0xFF0000;
      private static final int BYTE_2_SHIFT = 16;
  
      private static final int BYTE_3 = 3;
      private static final long BYTE_3_MASK = 0xFF000000L;
      private static final int BYTE_3_SHIFT = 24;
  
      private final long value;
  
      /** Central File Header Signature */
      public static final ZipLong CFH_SIG = new ZipLong(0X02014B50L);
  
      /** Local File Header Signature */
      public static final ZipLong LFH_SIG = new ZipLong(0X04034B50L);
  
      /**
       * Data Descriptor signature
       */
      public static final ZipLong DD_SIG = new ZipLong(0X08074B50L);
  
      /**
       * Value stored in size and similar fields if ZIP64 extensions are
       * used.
       */
      static final ZipLong ZIP64_MAGIC = new ZipLong(ZipConstants.ZIP64_MAGIC);
  
      /**
       * Create instance from a number.
       * @param value the long to store as a ZipLong
       * @since 1.1
       */
      public ZipLong(long value) {
          this.value = value;
      }
  
      /**
       * Create instance from bytes.
       * @param bytes the bytes to store as a ZipLong
       * @since 1.1
       */
      public ZipLong (byte[] bytes) {
          this(bytes, 0);
      }
  
      /**
       * Create instance from the four bytes starting at offset.
       * @param bytes the bytes to store as a ZipLong
       * @param offset the offset to start
       * @since 1.1
       */
      public ZipLong (byte[] bytes, int offset) {
          value = ZipLong.getValue(bytes, offset);
      }
  
      /**
       * Get value as four bytes in big endian byte order.
       * @since 1.1
       * @return value as four bytes in big endian order
       */
      public byte[] getBytes() {
          return ZipLong.getBytes(value);
      }
  
      /**
       * Get value as Java long.
       * @since 1.1
       * @return value as a long
       */
      public long getValue() {
          return value;
      }
  
      /**
       * Get value as four bytes in big endian byte order.
       * @param value the value to convert
       * @return value as four bytes in big endian byte order
       */
      public static byte[] getBytes(long value) {
          byte[] result = new byte[WORD];
          result[0] = (byte) ((value & BYTE_MASK));
          result[BYTE_1] = (byte) ((value & BYTE_1_MASK) >> BYTE_1_SHIFT);
          result[BYTE_2] = (byte) ((value & BYTE_2_MASK) >> BYTE_2_SHIFT);
          result[BYTE_3] = (byte) ((value & BYTE_3_MASK) >> BYTE_3_SHIFT);
          return result;
      }
  
      /**
       * Helper method to get the value as a Java long from four bytes starting at given array offset
       * @param bytes the array of bytes
       * @param offset the offset to start
       * @return the corresponding Java long value
       */
      public static long getValue(byte[] bytes, int offset) {
          long value = (bytes[offset + BYTE_3] << BYTE_3_SHIFT) & BYTE_3_MASK;
          value += (bytes[offset + BYTE_2] << BYTE_2_SHIFT) & BYTE_2_MASK;
          value += (bytes[offset + BYTE_1] << BYTE_1_SHIFT) & BYTE_1_MASK;
          value += (bytes[offset] & BYTE_MASK);
          return value;
      }
  
      /**
       * Helper method to get the value as a Java long from a four-byte array
       * @param bytes the array of bytes
       * @return the corresponding Java long value
       */
      public static long getValue(byte[] bytes) {
          return getValue(bytes, 0);
      }
  
      /**
       * Override to make two instances with same value equal.
       * @param o an object to compare
       * @return true if the objects are equal
       * @since 1.1
       */
      @Override
      public boolean equals(Object o) {
          if (o == null || !(o instanceof ZipLong)) {
              return false;
          }
          return value == ((ZipLong) o).getValue();
      }
  
      /**
       * Override to make two instances with same value equal.
       * @return the value stored in the ZipLong
       * @since 1.1
       */
      @Override
      public int hashCode() {
          return (int) value;
      }
  
      @Override
      public Object clone() {
          try {
              return super.clone();
          } catch (CloneNotSupportedException cnfe) {
              // impossible
              throw new RuntimeException(cnfe);
          }
      }
  
      @Override
      public String toString() {
          return "ZipLong value: " + value;
      }
  }
  