zoneinfofile.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 948 行 · 第 1/2 页

/*
 * @(#)ZoneInfoFile.java	1.10 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation. 
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 */

package sun.util.calendar;

import	java.io.File;
import	java.io.FileInputStream;
import	java.io.FileNotFoundException;
import	java.io.IOException;
import	java.lang.ref.SoftReference;
import	java.util.HashMap;
import	java.security.AccessController;
import	java.security.PrivilegedAction;
import	java.security.PrivilegedActionException;
import	java.security.PrivilegedExceptionAction;

/**
 * <code>ZoneInfoFile</code> reads Zone information files in the
 * &lt;java.home&gt;/lib/zi directory and provides time zone
 * information in the form of a {@link ZoneInfo} object. Also, it
 * reads the ZoneInfoMappings file to obtain time zone IDs information
 * that is used by the {@link ZoneInfo} class. The directory layout
 * and data file formats are as follows.
 *
 * <p><strong>Directory layout</strong><p>
 *
 * All zone data files and ZoneInfoMappings are put under the
 * &lt;java.home&gt;/lib/zi directory. A path name for a given time
 * zone ID is a concatenation of &lt;java.home&gt;/lib/zi/ and the
 * time zone ID. (The file separator is replaced with the platform
 * dependent value. e.g., '\' for Win32.) An example layout will look
 * like as follows.
 * <blockquote>
 * <pre>
 * &lt;java.home&gt;/lib/zi/Africa/Addis_Ababa
 *                   /Africa/Dakar
 *                   /America/Los_Angeles
 *                   /Asia/Singapore
 *                   /EET
 *                   /Europe/Oslo
 *                   /GMT
 *                   /Pacific/Galapagos
 *                       ...
 *                   /ZoneInfoMappings
 * </pre>
 * </blockquote>
 *
 * A zone data file has specific information of each zone.
 * <code>ZoneInfoMappings</code> has global information of zone IDs so
 * that the information can be obtained without instantiating all time
 * zones.
 *
 * <p><strong>File format</strong><p>
 *
 * Two binary-file formats based on a simple Tag-Length-Value format are used
 * to describe TimeZone information. The generic format of a data file is:
 * <blockquote>
 * <pre>
 *    DataFile {
 *      u1              magic[7];
 *      u1              version;
 *      data_item       data[];
 *    }
 * </pre>
 * </blockquote>
 * where <code>magic</code> is a magic number identifying a file
 * format, <code>version</code> is the format version number, and
 * <code>data</code> is one or more <code>data_item</code>s. The
 * <code>data_item</code> structure is:
 * <blockquote>
 * <pre>
 *    data_item {
 *      u1              tag;
 *      u2              length;
 *      u1              value[length];
 *    }
 * </pre>
 * </blockquote>
 * where <code>tag</code> indicates the data type of the item,
 * <code>length</code> is a byte count of the following
 * <code>value</code> that is the content of item data.
 * <p>
 * All data is stored in the big-endian order. There is no boundary
 * alignment between date items.
 *
 * <p><strong>1. ZoneInfo data file</strong><p>
 *
 * Each ZoneInfo data file consists of the following members.
 * <br>
 * <blockquote>
 * <pre>
 *    ZoneInfoDataFile {
 *      u1              magic[7];
 *      u1              version;
 *      SET OF<sup>1</sup> {
 *        transition            transitions<sup>2</sup>;
 *        offset_table          offsets<sup>2</sup>;
 *        simpletimezone        stzparams<sup>2</sup>;
 *        raw_offset            rawoffset;
 *        dstsaving             dst;
 *        checksum              crc32;
 *        gmtoffsetwillchange   gmtflag<sup>2</sup>;
 *      }
 *   }
 *   1: an unordered collection of zero or one occurrences of each item
 *   2: optional item
 * </pre>
 * </blockquote>
 * <code>magic</code> is a byte-string constant identifying the
 * ZoneInfo data file.  This field must be <code>"javazi&#92;0"</code>
 * defined as {@link #JAVAZI_LABEL}.
 * <p>
 * <code>version</code> is the version number of the file format. This
 * will be used for compatibility check. This field must be
 * <code>0x01</code> in this version.
 * <p>
 * <code>transition</code>, <code>offset_table</code> and
 * <code>simpletimezone</code> have information of time transition
 * from the past to the future.  Therefore, these structures don't
 * exist if the zone didn't change zone names and haven't applied DST in
 * the past, and haven't planned to apply it.  (e.g. Asia/Tokyo zone)
 * <p>
 * <code>raw_offset</code>, <code>dstsaving</code> and <code>checksum</code>
 * exist in every zoneinfo file. They are used by TimeZone.class indirectly.
 *
 * <p><strong>1.1 <code>transition</code> structure</strong><p><a name="transition"></a>
 * <blockquote>
 * <pre>
 *    transition {
 *      u1      tag;              // 0x04 : constant
 *      u2      length;           // byte length of whole values
 *      s8      value[length/8];  // transitions in `long'
 *    }
 * </pre>
 * </blockquote>
 * See {@link ZoneInfo#transitions ZoneInfo.transitions} about the value.
 *
 * <p><strong>1.2 <code>offset_table</code> structure</strong><p>
 * <blockquote>
 * <pre>
 *    offset_table {
 *      u1      tag;              // 0x05 : constant
 *      u2      length;           // byte length of whole values
 *      s4      value[length/4];  // offset values in `int'
 *    }
 * </pre>
 * </blockquote>
 *
 * <p><strong>1.3 <code>simpletimezone</code> structure</strong><p>
 * See {@link ZoneInfo#simpleTimeZoneParams ZoneInfo.simpleTimeZoneParams}
 * about the value.
 * <blockquote>
 * <pre>
 *    simpletimezone {
 *      u1      tag;              // 0x06 : constant
 *      u2      length;           // byte length of whole values
 *      s4      value[length/4];  // SimpleTimeZone parameters
 *    }
 * </pre>
 * </blockquote>
 * See {@link ZoneInfo#offsets ZoneInfo.offsets} about the value.
 *
 * <p><strong>1.4 <code>raw_offset</code> structure</strong><p>
 * <blockquote>
 * <pre>
 *    raw_offset {
 *      u1	tag;              // 0x01 : constant
 *      u2	length;           // must be 4.
 *      s4	value;            // raw GMT offset [millisecond]
 *    }
 * </pre>
 * </blockquote>
 * See {@link ZoneInfo#rawOffset ZoneInfo.rawOffset} about the value.
 *
 * <p><strong>1.5 <code>dstsaving</code> structure</strong><p>
 * Value has dstSaving in seconds. 
 * <blockquote>
 * <pre>
 *    dstsaving {
 *      u1	tag;              // 0x02 : constant
 *      u2	length;           // must be 2.
 *      s2	value;            // DST save value [second]
 *    }
 * </pre>
 * </blockquote>
 * See {@link ZoneInfo#dstSavings ZoneInfo.dstSavings} about value.
 *
 * <p><strong>1.6 <code>checksum</code> structure</strong><p>
 * <blockquote>
 * <pre>
 *    checksum {
 *      u1	tag;              // 0x03 : constant
 *      u2	length;           // must be 4.
 *      s4	value;            // CRC32 value of transitions
 *    }
 * </pre>
 * </blockquote>
 * See {@link ZoneInfo#checksum ZoneInfo.checksum}.
 *
 * <p><strong>1.7 <code>gmtoffsetwillchange</code> structure</strong><p>
 * This record has a flag value for {@link ZoneInfo#rawOffsetWillChange}.
 * If this record is not present in a zoneinfo file, 0 is assumed for
 * the value.
 * <blockquote>
 * <pre>
 *    gmtoffsetwillchange {
 *      u1      tag;             // 0x07 : constant
 *      u2      length;          // must be 1.
 *      u1      value;           // 1: if the GMT raw offset will change
 *                               // in the future, 0, otherwise.
 *     }
 * </pre>
 * </blockquote>
 *
 *
 * <p><strong>2. ZoneInfoMappings file</strong><p>
 *
 * The ZoneInfoMappings file consists of the following members.
 * <br>
 * <blockquote>
 * <pre>
 *    ZoneInfoMappings {
 *      u1      magic[7];
 *      u1      version;
 *      SET OF {
 *        versionName                   version;
 *        zone_id_table                 zoneIDs;
 *        raw_offset_table              rawoffsets;
 *        raw_offset_index_table        rawoffsetindices;
 *        alias_table                   aliases;
 *      }
 *   }
 * </pre>
 * </blockquote>
 *
 * <code>magic</code> is a byte-string constant which has the file type. 
 * This field must be <code>"javazm&#92;0"</code> defined as {@link #JAVAZM_LABEL}.
 * <p>
 * <code>version</code> is the version number of this file
 * format. This will be used for compatibility check. This field must
 * be <code>0x01</code> in this version.
 * <p>
 * <code>versionName</code> shows which version of Olson's data has been used 
 * to generate this ZoneInfoMappings. (e.g. <code>tzdata2000g</code>) <br>
 * This field is for trouble-shooting and isn't usually used in runtime.
 * <p>
 * <code>zone_id_table</code, <code>raw_offset_index_table</code> and
 * <code>alias_table</code> are general information of supported
 * zones.
 *
 * <p><strong>2.1 <code>zone_id_table</code> structure</strong><p>
 * <br>
 * <blockquote>
 * <pre>
 *    zone_id_table {
 *      u1      tag;              // 0x40 : constant
 *      u2      length;           // byte length of whole values
 *      u2      zone_id_count;
 *      zone_id value[zone_id_count];
 *    }
 *
 *    zone_id {
 *      u1      byte_length;      // byte length of id
 *      u1      id[byte_length];  // zone name string
 *    }
 * </pre>
 * </blockquote>
 *
 * <p><strong>2.2 <code>raw_offset_table</code> structure</strong><p>
 * <br>
 * <blockquote>
 * <pre>
 *    raw_offset_table {
 *      u1      tag;              // 0x41 : constant
 *      u2      length;           // byte length of whole values
 *      s4      value[length/4];  // raw GMT offset in milliseconds
 *   }
 * </pre>
 * </blockquote>
 *
 * <p><strong>2.3 <code>raw_offset_index_table</code> structure</strong><p>
 * <br>
 * <blockquote>
 * <pre>
 *    raw_offset_index_table {
 *      u1      tag;              // 0x42 : constant
 *      u2      length;           // byte length of whole values
 *      u1      value[length];
 *    }
 * </pre>
 * </blockquote>
 *
 * <p><strong>2.4 <code>alias_table</code> structure</strong><p>
 * <br>
 * <blockquote>
 * <pre>
 *   alias_table {
 *      u1      tag;              // 0x43 : constant
 *      u2      length;           // byte length of whole values
 *      u2      nentries;         // number of id-pairs
 *      id_pair value[nentries];
 *   }
 *
 *   id_pair {
 *      zone_id aliasname;
 *      zone_id ID;
 *   }
 * </pre>
 * </blockquote>
 *
 * <p><strong>2.5 <code>versionName</code> structure</strong><p>
 * <br>
 * <blockquote>
 * <pre>
 *   versionName {
 *      u1      tag;              // 0x44 : constant
 *      u2      length;           // byte length of whole values
 *      u1      value[length];
 *   }
 * </pre>
 * </blockquote>

 * @since 1.4
 */

public class ZoneInfoFile {

    /**
     * The magic number for the ZoneInfo data file format.
     */
    public static final byte[]	JAVAZI_LABEL = {
	(byte)'j', (byte)'a', (byte)'v', (byte)'a', (byte)'z', (byte)'i', (byte)'\0'
    };
    private static final int	JAVAZI_LABEL_LENGTH = JAVAZI_LABEL.length;

    /**
     * The ZoneInfo data file formation version number.
     */
    public static final	byte	JAVAZI_VERSION = 0x01;

    /**
     * Raw offset data item tag.
     */
    public static final byte	TAG_RawOffset = 1;

    /**
     * Known last Daylight Saving Time save value data item tag.
     */
    public static final byte	TAG_LastDSTSaving = 2;

    /**
     * Checksum data item tag.
     */
    public static final byte	TAG_CRC32 = 3;

    /**
     * Transition data item tag.
     */
    public static final byte	TAG_Transition = 4;

    /**
     * Offset table data item tag.
     */
    public static final byte	TAG_Offset = 5;

    /**
     * SimpleTimeZone parameters data item tag.
     */
    public static final byte	TAG_SimpleTimeZone = 6;

    /**
     * Raw GMT offset will change in the future.
     */
    public static final byte	TAG_GMTOffsetWillChange = 7;


    /**
     * The ZoneInfoMappings file name.
     */
    public static final String	JAVAZM_FILE_NAME = "ZoneInfoMappings";

    /**
     * The magic number for the ZoneInfoMappings file format.
     */
    public static final byte[]	JAVAZM_LABEL = {
	(byte)'j', (byte)'a', (byte)'v', (byte)'a', (byte)'z', (byte)'m', (byte)'\0'
    };
    private static final int	JAVAZM_LABEL_LENGTH = JAVAZM_LABEL.length;

    /**
     * The ZoneInfoMappings file format version number.
     */
    public static final	byte	JAVAZM_VERSION = 0x01;

    /**
     * Time zone IDs data item tag.
     */
    public static final byte	TAG_ZoneIDs = 64;

    /**
     * Raw GMT offsets table data item tag.
     */
    public static final byte	TAG_RawOffsets = 65;

    /**
     * Indices to the raw GMT offset table data item tag.
     */
    public static final byte	TAG_RawOffsetIndices = 66;

    /**
     * Time zone aliases table data item tag.
     */
    public static final byte	TAG_ZoneAliases = 67;

    /**
     * Olson's public zone information version tag.
     */
    public static final byte	TAG_TZDataVersion = 68;

    private static HashMap zoneInfoObjects = null;

    /**
     * Converts the given time zone ID to a platform dependent path
     * name. For example, "America/Los_Angeles" is converted to
     * "America\Los_Angeles" on Win32.
     * @return a modified ID replacing '/' with {@link
     * java.io.File#separatorChar File.separatorChar} if needed.
     */
    public static String getFileName(String ID) {
	if (File.separatorChar == '/') {
	    return ID;
	}
	return ID.replace('/', File.separatorChar);
    }

    /**
     * Gets a ZoneInfo with the given GMT offset. The object
     * has its ID in the format of GMT{+|-}hh:mm.
     *
     * @param originalId the given custom id (before normalized such as "GMT+9")
     * @param gmtOffset GMT offset <em>in minutes</em>
     * @return a ZoneInfo constructed with the given GMT offset
     */
    public static ZoneInfo getCustomTimeZone(String originalId, int gmtOffset) {
	char sign;
	int offset;

	if (gmtOffset >= 0) {
	    sign = '+';
	    offset = gmtOffset;
	} else {