Android Open Source - JiangHomeStyle_Android_Phone Zip Util

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License

The source code is released under:

Apache License

Java Source Code

/*
 *  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
 */*ww w .ja  va 2 s  .  co  m*/
 *      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 org.apache.tools.zip;

import java.io.IOException;
import java.util.Calendar;
import java.util.Date;
import java.util.zip.CRC32;

/**
 * Utility class for handling DOS and Java time conversions.
 * 
 * @since Ant 1.8.1
 */
public abstract class ZipUtil
{
  /**
   * Smallest date/time ZIP can handle.
   */
  private static final byte[] DOS_TIME_MIN = ZipLong.getBytes(0x00002100L);

  /**
   * Convert a Date object to a DOS date/time field.
   * 
   * @param time
   *            the <code>Date</code> to convert
   * @return the date as a <code>ZipLong</code>
   */
  public static ZipLong toDosTime(Date time)
  {
    return new ZipLong(toDosTime(time.getTime()));
  }

  /**
   * Convert a Date object to a DOS date/time field.
   * 
   * <p>
   * Stolen from InfoZip's <code>fileio.c</code>
   * </p>
   * 
   * @param t
   *            number of milliseconds since the epoch
   * @return the date as a byte array
   */
  public static byte[] toDosTime(long t)
  {
    Calendar c = Calendar.getInstance();
    c.setTimeInMillis(t);

    int year = c.get(Calendar.YEAR);
    if (year < 1980)
    {
      return copy(DOS_TIME_MIN); // stop callers from changing the array
    }
    int month = c.get(Calendar.MONTH) + 1;
    long value = ((year - 1980) << 25) | (month << 21) | (c.get(Calendar.DAY_OF_MONTH) << 16)
        | (c.get(Calendar.HOUR_OF_DAY) << 11) | (c.get(Calendar.MINUTE) << 5) | (c.get(Calendar.SECOND) >> 1);
    return ZipLong.getBytes(value);
  }

  /**
   * Assumes a negative integer really is a positive integer that has wrapped
   * around and re-creates the original value.
   * 
   * <p>
   * This methods is no longer used as of Apache Ant 1.9.0
   * </p>
   * 
   * @param i
   *            the value to treat as unsigned int.
   * @return the unsigned int as a long.
   */
  public static long adjustToLong(int i)
  {
    if (i < 0)
    {
      return 2 * ((long) Integer.MAX_VALUE) + 2 + i;
    }
    else
    {
      return i;
    }
  }

  /**
   * Convert a DOS date/time field to a Date object.
   * 
   * @param zipDosTime
   *            contains the stored DOS time.
   * @return a Date instance corresponding to the given time.
   */
  public static Date fromDosTime(ZipLong zipDosTime)
  {
    long dosTime = zipDosTime.getValue();
    return new Date(dosToJavaTime(dosTime));
  }

  /**
   * Converts DOS time to Java time (number of milliseconds since epoch).
   */
  public static long dosToJavaTime(long dosTime)
  {
    Calendar cal = Calendar.getInstance();
    // CheckStyle:MagicNumberCheck OFF - no point
    cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
    cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
    cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
    cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
    cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
    cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
    // CheckStyle:MagicNumberCheck ON
    return cal.getTime().getTime();
  }

  /**
   * If the entry has Unicode*ExtraFields and the CRCs of the names/comments
   * match those of the extra fields, transfer the known Unicode values from
   * the extra field.
   */
  static void setNameAndCommentFromExtraFields(ZipEntry ze, byte[] originalNameBytes, byte[] commentBytes)
  {
    UnicodePathExtraField name = (UnicodePathExtraField) ze.getExtraField(UnicodePathExtraField.UPATH_ID);
    String originalName = ze.getName();
    String newName = getUnicodeStringIfOriginalMatches(name, originalNameBytes);
    if (newName != null && !originalName.equals(newName))
    {
      ze.setName(newName);
    }

    if (commentBytes != null && commentBytes.length > 0)
    {
      UnicodeCommentExtraField cmt = (UnicodeCommentExtraField) ze.getExtraField(UnicodeCommentExtraField.UCOM_ID);
      String newComment = getUnicodeStringIfOriginalMatches(cmt, commentBytes);
      if (newComment != null)
      {
        ze.setComment(newComment);
      }
    }
  }

  /**
   * If the stored CRC matches the one of the given name, return the Unicode
   * name of the given field.
   * 
   * <p>
   * If the field is null or the CRCs don't match, return null instead.
   * </p>
   */
  private static String getUnicodeStringIfOriginalMatches(AbstractUnicodeExtraField f, byte[] orig)
  {
    if (f != null)
    {
      CRC32 crc32 = new CRC32();
      crc32.update(orig);
      long origCRC32 = crc32.getValue();

      if (origCRC32 == f.getNameCRC32())
      {
        try
        {
          return ZipEncodingHelper.UTF8_ZIP_ENCODING.decode(f.getUnicodeName());
        }
        catch (IOException ex)
        {
          // UTF-8 unsupported? should be impossible the
          // Unicode*ExtraField must contain some bad bytes

          // TODO log this anywhere?
          return null;
        }
      }
    }
    return null;
  }

  /**
   * Create a copy of the given array - or return null if the argument is
   * null.
   */
  static byte[] copy(byte[] from)
  {
    if (from != null)
    {
      byte[] to = new byte[from.length];
      System.arraycopy(from, 0, to, 0, to.length);
      return to;
    }
    return null;
  }

  /**
   * Whether this library is able to read or write the given entry.
   */
  static boolean canHandleEntryData(ZipEntry entry)
  {
    return supportsEncryptionOf(entry) && supportsMethodOf(entry);
  }

  /**
   * Whether this library supports the encryption used by the given entry.
   * 
   * @return true if the entry isn't encrypted at all
   */
  private static boolean supportsEncryptionOf(ZipEntry entry)
  {
    return !entry.getGeneralPurposeBit().usesEncryption();
  }

  /**
   * Whether this library supports the compression method used by the given
   * entry.
   * 
   * @return true if the compression method is STORED or DEFLATED
   */
  private static boolean supportsMethodOf(ZipEntry entry)
  {
    return entry.getMethod() == ZipEntry.STORED || entry.getMethod() == ZipEntry.DEFLATED;
  }

  /**
   * Checks whether the entry requires features not (yet) supported by the
   * library and throws an exception if it does.
   */
  static void checkRequestedFeatures(ZipEntry ze) throws UnsupportedZipFeatureException
  {
    if (!supportsEncryptionOf(ze))
    {
      throw new UnsupportedZipFeatureException(UnsupportedZipFeatureException.Feature.ENCRYPTION, ze);
    }
    if (!supportsMethodOf(ze))
    {
      throw new UnsupportedZipFeatureException(UnsupportedZipFeatureException.Feature.METHOD, ze);
    }
  }
}

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