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comparison lib/mod/src/de/masters_of_disaster/ant/tasks/ar/ArEntry.java @ 33:3d86f0391168

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Work on improving the build system.
author David Barts <davidb@stashtea.com>
date Fri, 24 Apr 2020 19:45:57 -0700
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32:c06edc56669b 33:3d86f0391168
1 package de.masters_of_disaster.ant.tasks.ar;
2
3 import java.io.File;
4 import java.util.Date;
5
6 /**
7 * This class represents an entry in an Ar archive. It consists
8 * of the entry's header, as well as the entry's File. Entries
9 * can be instantiated in one of three ways, depending on how
10 * they are to be used.
11 * <p>
12 * ArEntries that are created from the header bytes read from
13 * an archive are instantiated with the ArEntry( byte[] )
14 * constructor. These entries will be used when extracting from
15 * or listing the contents of an archive. These entries have their
16 * header filled in using the header bytes. They also set the File
17 * to null, since they reference an archive entry not a file.
18 * <p>
19 * ArEntries that are created from Files that are to be written
20 * into an archive are instantiated with the ArEntry( File )
21 * constructor. These entries have their header filled in using
22 * the File's information. They also keep a reference to the File
23 * for convenience when writing entries.
24 * <p>
25 * Finally, ArEntries can be constructed from nothing but a name.
26 * This allows the programmer to construct the entry by hand, for
27 * instance when only an InputStream is available for writing to
28 * the archive, and the header information is constructed from
29 * other information. In this case the header fields are set to
30 * defaults and the File is set to null.
31 *
32 * <p>
33 * The C structure for an Ar Entry's header is:
34 * <pre>
35 * struct header {
36 * char filename[16];
37 * char filedate[12];
38 * char uid[6];
39 * char gid[6];
40 * char mode[8];
41 * char size[10];
42 * char magic[2];
43 * } header;
44 * </pre>
45 *
46 */
47
48 public class ArEntry implements ArConstants {
49 /** The entry's filename. */
50 private StringBuffer filename;
51
52 /** The entry's file date. */
53 private long fileDate;
54
55 /** The entry's user id. */
56 private int userId;
57
58 /** The entry's group id. */
59 private int groupId;
60
61 /** The entry's permission mode. */
62 private int mode;
63
64 /** The entry's size. */
65 private long size;
66
67 /** The entry's magic tag. */
68 private StringBuffer magic;
69
70 /** The entry's file reference */
71 private File file;
72
73 /** Default permissions bits for files */
74 public static final int DEFAULT_FILE_MODE = 0100644;
75
76 /** Convert millis to seconds */
77 public static final int MILLIS_PER_SECOND = 1000;
78
79 /**
80 * Construct an empty entry and prepares the header values.
81 */
82 private ArEntry () {
83 this.magic = new StringBuffer(HEADERMAGIC);
84 this.filename = new StringBuffer();
85 this.userId = 0;
86 this.groupId = 0;
87 this.file = null;
88 }
89
90 /**
91 * Construct an entry with only a name. This allows the programmer
92 * to construct the entry's header "by hand". File is set to null.
93 *
94 * @param name the entry name
95 */
96 public ArEntry(String name) {
97 this();
98 if (name.endsWith("/")) {
99 throw new IllegalArgumentException("ar archives can only contain files");
100 }
101 this.filename = new StringBuffer(name);
102 this.mode = DEFAULT_FILE_MODE;
103 this.userId = 0;
104 this.groupId = 0;
105 this.size = 0;
106 this.fileDate = (new Date()).getTime() / MILLIS_PER_SECOND;
107 }
108
109 /**
110 * Construct an entry for a file. File is set to file, and the
111 * header is constructed from information from the file.
112 *
113 * @param file The file that the entry represents.
114 */
115 public ArEntry(File file) {
116 this();
117 if (file.isDirectory()) {
118 throw new IllegalArgumentException("ar archives can only contain files");
119 }
120 this.file = file;
121 this.filename = new StringBuffer(file.getName());
122 this.fileDate = file.lastModified() / MILLIS_PER_SECOND;
123 this.mode = DEFAULT_FILE_MODE;
124 this.size = file.length();
125 }
126
127 /**
128 * Construct an entry from an archive's header bytes. File is set
129 * to null.
130 *
131 * @param headerBuf The header bytes from an ar archive entry.
132 */
133 public ArEntry(byte[] headerBuf) {
134 this();
135 this.parseArHeader(headerBuf);
136 }
137
138 /**
139 * Determine if the two entries are equal. Equality is determined
140 * by the header names being equal.
141 *
142 * @param it Entry to be checked for equality.
143 * @return True if the entries are equal.
144 */
145 public boolean equals(ArEntry it) {
146 return this.getFilename().equals(it.getFilename());
147 }
148
149 /**
150 * Determine if the two entries are equal. Equality is determined
151 * by the header names being equal.
152 *
153 * @param it Entry to be checked for equality.
154 * @return True if the entries are equal.
155 */
156 public boolean equals(Object it) {
157 if (it == null || getClass() != it.getClass()) {
158 return false;
159 }
160 return equals((ArEntry) it);
161 }
162
163 /**
164 * Hashcodes are based on entry names.
165 *
166 * @return the entry hashcode
167 */
168 public int hashCode() {
169 return getFilename().hashCode();
170 }
171
172 /**
173 * Get this entry's name.
174 *
175 * @return This entry's name.
176 */
177 public String getFilename() {
178 return this.filename.toString();
179 }
180
181 /**
182 * Set this entry's name.
183 *
184 * @param name This entry's new name.
185 */
186 public void setFilename(String filename) {
187 this.filename = new StringBuffer(filename);
188 }
189
190 /**
191 * Set the mode for this entry
192 *
193 * @param mode the mode for this entry
194 */
195 public void setMode(int mode) {
196 this.mode = mode;
197 }
198
199 /**
200 * Get this entry's user id.
201 *
202 * @return This entry's user id.
203 */
204 public int getUserId() {
205 return this.userId;
206 }
207
208 /**
209 * Set this entry's user id.
210 *
211 * @param userId This entry's new user id.
212 */
213 public void setUserId(int userId) {
214 this.userId = userId;
215 }
216
217 /**
218 * Get this entry's group id.
219 *
220 * @return This entry's group id.
221 */
222 public int getGroupId() {
223 return this.groupId;
224 }
225
226 /**
227 * Set this entry's group id.
228 *
229 * @param groupId This entry's new group id.
230 */
231 public void setGroupId(int groupId) {
232 this.groupId = groupId;
233 }
234
235 /**
236 * Convenience method to set this entry's group and user ids.
237 *
238 * @param userId This entry's new user id.
239 * @param groupId This entry's new group id.
240 */
241 public void setIds(int userId, int groupId) {
242 this.setUserId(userId);
243 this.setGroupId(groupId);
244 }
245
246 /**
247 * Set this entry's modification time. The parameter passed
248 * to this method is in "Java time".
249 *
250 * @param time This entry's new modification time.
251 */
252 public void setFileDate(long time) {
253 this.fileDate = time / MILLIS_PER_SECOND;
254 }
255
256 /**
257 * Set this entry's modification time.
258 *
259 * @param time This entry's new modification time.
260 */
261 public void setFileDate(Date time) {
262 this.fileDate = time.getTime() / MILLIS_PER_SECOND;
263 }
264
265 /**
266 * Get this entry's modification time.
267 *
268 * @return time This entry's new modification time.
269 */
270 public Date getFileDate() {
271 return new Date(this.fileDate * MILLIS_PER_SECOND);
272 }
273
274 /**
275 * Get this entry's file.
276 *
277 * @return This entry's file.
278 */
279 public File getFile() {
280 return this.file;
281 }
282
283 /**
284 * Get this entry's mode.
285 *
286 * @return This entry's mode.
287 */
288 public int getMode() {
289 return this.mode;
290 }
291
292 /**
293 * Get this entry's file size.
294 *
295 * @return This entry's file size.
296 */
297 public long getSize() {
298 return this.size;
299 }
300
301 /**
302 * Set this entry's file size.
303 *
304 * @param size This entry's new file size.
305 */
306 public void setSize(long size) {
307 this.size = size;
308 }
309
310 /**
311 * Write an entry's header information to a header buffer.
312 *
313 * @param outbuf The tar entry header buffer to fill in.
314 */
315 public void writeEntryHeader(byte[] outbuf) {
316 int offset = 0;
317
318 offset = ArUtils.getNameBytes(this.filename, outbuf, offset, NAMELEN);
319 offset = ArUtils.getLongBytes(this.fileDate, outbuf, offset, FILEDATELEN);
320 offset = ArUtils.getIntegerBytes(this.userId, outbuf, offset, UIDLEN);
321 offset = ArUtils.getIntegerBytes(this.groupId, outbuf, offset, GIDLEN);
322 offset = ArUtils.getOctalBytes(this.mode, outbuf, offset, MODELEN);
323 offset = ArUtils.getLongBytes(this.size, outbuf, offset, SIZELEN);
324 offset = ArUtils.getNameBytes(this.magic, outbuf, offset, MAGICLEN);
325
326 while (offset < outbuf.length) {
327 outbuf[offset++] = 0;
328 }
329 }
330
331 /**
332 * Parse an entry's header information from a header buffer.
333 *
334 * @param header The ar entry header buffer to get information from.
335 */
336 public void parseArHeader(byte[] header) {
337 throw new UnsupportedOperationException("parseArHeader(byte[]) not yet implmented");
338 // int offset = 0;
339 //
340 // this.filename = TarUtils.parseName(header, offset, NAMELEN);
341 // offset += NAMELEN;
342 // this.fileDate = TarUtils.parseOctal(header, offset, FILEDATELEN);
343 // offset += FILEDATELEN;
344 // this.userId = (int) TarUtils.parseOctal(header, offset, UIDLEN);
345 // offset += UIDLEN;
346 // this.groupId = (int) TarUtils.parseOctal(header, offset, GIDLEN);
347 // offset += GIDLEN;
348 // this.mode = (int) TarUtils.parseOctal(header, offset, MODELEN);
349 // offset += MODELEN;
350 // this.size = TarUtils.parseOctal(header, offset, SIZELEN);
351 // offset += SIZELEN;
352 // this.magic = TarUtils.parseName(header, offset, MAGICLEN);
353 // offset += MAGICLEN;
354 }
355 }