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1
18
19 package org.apache.tools.zip;
20
21 import java.util.Hashtable  ;
22 import java.util.Vector ;
23 import java.util.zip.ZipException ;
24
25
29 public class ExtraFieldUtils {
30
31
36 private static Hashtable implementations;
37
38 static {
39 implementations = new Hashtable ();
40 register(AsiExtraField.class);
41 register(JarMarker.class);
42 }
43
44
53 public static void register(Class c) {
54 try {
55 ZipExtraField ze = (ZipExtraField) c.newInstance();
56 implementations.put(ze.getHeaderId(), c);
57 } catch (ClassCastException cc) {
58 throw new RuntimeException (c + " doesn\'t implement ZipExtraField");
59 } catch (InstantiationException ie) {
60 throw new RuntimeException (c + " is not a concrete class");
61 } catch (IllegalAccessException ie) {
62 throw new RuntimeException (c + "\'s no-arg constructor is not public");
63 }
64 }
65
66
75 public static ZipExtraField createExtraField(ZipShort headerId)
76 throws InstantiationException , IllegalAccessException {
77 Class c = (Class ) implementations.get(headerId);
78 if (c != null) {
79 return (ZipExtraField) c.newInstance();
80 }
81 UnrecognizedExtraField u = new UnrecognizedExtraField();
82 u.setHeaderId(headerId);
83 return u;
84 }
85
86
94 public static ZipExtraField[] parse(byte[] data) throws ZipException {
95 Vector v = new Vector ();
96 int start = 0;
97 while (start <= data.length - 4) {
98 ZipShort headerId = new ZipShort(data, start);
99 int length = (new ZipShort(data, start + 2)).getValue();
100 if (start + 4 + length > data.length) {
101 throw new ZipException ("data starting at " + start
102 + " is in unknown format");
103 }
104 try {
105 ZipExtraField ze = createExtraField(headerId);
106 ze.parseFromLocalFileData(data, start + 4, length);
107 v.addElement(ze);
108 } catch (InstantiationException ie) {
109 throw new ZipException (ie.getMessage());
110 } catch (IllegalAccessException iae) {
111 throw new ZipException (iae.getMessage());
112 }
113 start += (length + 4);
114 }
115 if (start != data.length) { throw new ZipException ("data starting at " + start
117 + " is in unknown format");
118 }
119
120 ZipExtraField[] result = new ZipExtraField[v.size()];
121 v.copyInto(result);
122 return result;
123 }
124
125
131 public static byte[] mergeLocalFileDataData(ZipExtraField[] data) {
132 int sum = 4 * data.length;
133 for (int i = 0; i < data.length; i++) {
134 sum += data[i].getLocalFileDataLength().getValue();
135 }
136 byte[] result = new byte[sum];
137 int start = 0;
138 for (int i = 0; i < data.length; i++) {
139 System.arraycopy(data[i].getHeaderId().getBytes(),
140 0, result, start, 2);
141 System.arraycopy(data[i].getLocalFileDataLength().getBytes(),
142 0, result, start + 2, 2);
143 byte[] local = data[i].getLocalFileDataData();
144 System.arraycopy(local, 0, result, start + 4, local.length);
145 start += (local.length + 4);
146 }
147 return result;
148 }
149
150
156 public static byte[] mergeCentralDirectoryData(ZipExtraField[] data) {
157 int sum = 4 * data.length;
158 for (int i = 0; i < data.length; i++) {
159 sum += data[i].getCentralDirectoryLength().getValue();
160 }
161 byte[] result = new byte[sum];
162 int start = 0;
163 for (int i = 0; i < data.length; i++) {
164 System.arraycopy(data[i].getHeaderId().getBytes(),
165 0, result, start, 2);
166 System.arraycopy(data[i].getCentralDirectoryLength().getBytes(),
167 0, result, start + 2, 2);
168 byte[] local = data[i].getCentralDirectoryData();
169 System.arraycopy(local, 0, result, start + 4, local.length);
170 start += (local.length + 4);
171 }
172 return result;
173 }
174 }
175 |
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