001: /*
002: * Licensed to the Apache Software Foundation (ASF) under one or more
003: * contributor license agreements. See the NOTICE file distributed with
004: * this work for additional information regarding copyright ownership.
005: * The ASF licenses this file to You under the Apache License, Version 2.0
006: * (the "License"); you may not use this file except in compliance with
007: * the License. You may obtain a copy of the License at
008: *
009: * http://www.apache.org/licenses/LICENSE-2.0
010: *
011: * Unless required by applicable law or agreed to in writing, software
012: * distributed under the License is distributed on an "AS IS" BASIS,
013: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014: * See the License for the specific language governing permissions and
015: * limitations under the License.
016: *
017: */
018:
019: package org.apache.tools.zip;
020:
021: /**
022: * Utility class that represents a four byte integer with conversion
023: * rules for the big endian byte order of ZIP files.
024: *
025: */
026: public final class ZipLong implements Cloneable {
027:
028: private long value;
029:
030: /**
031: * Create instance from a number.
032: * @param value the long to store as a ZipLong
033: * @since 1.1
034: */
035: public ZipLong(long value) {
036: this .value = value;
037: }
038:
039: /**
040: * Create instance from bytes.
041: * @param bytes the bytes to store as a ZipLong
042: * @since 1.1
043: */
044: public ZipLong(byte[] bytes) {
045: this (bytes, 0);
046: }
047:
048: /**
049: * Create instance from the four bytes starting at offset.
050: * @param bytes the bytes to store as a ZipLong
051: * @param offset the offset to start
052: * @since 1.1
053: */
054: public ZipLong(byte[] bytes, int offset) {
055: value = ZipLong.getValue(bytes, offset);
056: }
057:
058: /**
059: * Get value as four bytes in big endian byte order.
060: * @since 1.1
061: * @return value as four bytes in big endian order
062: */
063: public byte[] getBytes() {
064: return ZipLong.getBytes(value);
065: }
066:
067: /**
068: * Get value as Java long.
069: * @since 1.1
070: * @return value as a long
071: */
072: public long getValue() {
073: return value;
074: }
075:
076: /**
077: * Get value as four bytes in big endian byte order.
078: * @param value the value to convert
079: * @return value as four bytes in big endian byte order
080: */
081: public static byte[] getBytes(long value) {
082: byte[] result = new byte[4];
083: result[0] = (byte) ((value & 0xFF));
084: result[1] = (byte) ((value & 0xFF00) >> 8);
085: result[2] = (byte) ((value & 0xFF0000) >> 16);
086: result[3] = (byte) ((value & 0xFF000000L) >> 24);
087: return result;
088: }
089:
090: /**
091: * Helper method to get the value as a Java long from four bytes starting at given array offset
092: * @param bytes the array of bytes
093: * @param offset the offset to start
094: * @return the correspondanding Java long value
095: */
096: public static long getValue(byte[] bytes, int offset) {
097: long value = (bytes[offset + 3] << 24) & 0xFF000000L;
098: value += (bytes[offset + 2] << 16) & 0xFF0000;
099: value += (bytes[offset + 1] << 8) & 0xFF00;
100: value += (bytes[offset] & 0xFF);
101: return value;
102: }
103:
104: /**
105: * Helper method to get the value as a Java long from a four-byte array
106: * @param bytes the array of bytes
107: * @return the correspondanding Java long value
108: */
109: public static long getValue(byte[] bytes) {
110: return getValue(bytes, 0);
111: }
112:
113: /**
114: * Override to make two instances with same value equal.
115: * @param o an object to compare
116: * @return true if the objects are equal
117: * @since 1.1
118: */
119: public boolean equals(Object o) {
120: if (o == null || !(o instanceof ZipLong)) {
121: return false;
122: }
123: return value == ((ZipLong) o).getValue();
124: }
125:
126: /**
127: * Override to make two instances with same value equal.
128: * @return the value stored in the ZipLong
129: * @since 1.1
130: */
131: public int hashCode() {
132: return (int) value;
133: }
134: }
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