1 /*
2 * Copyright (c) 1994, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.nio.channels.FileChannel;
29 import java.util.concurrent.atomic.AtomicBoolean;
30 import jdk.internal.misc.JavaIORandomAccessFileAccess;
31 import jdk.internal.misc.SharedSecrets;
32 import sun.nio.ch.FileChannelImpl;
33
34
35 /**
36 * Instances of this class support both reading and writing to a
37 * random access file. A random access file behaves like a large
38 * array of bytes stored in the file system. There is a kind of cursor,
39 * or index into the implied array, called the <em>file pointer</em>;
40 * input operations read bytes starting at the file pointer and advance
41 * the file pointer past the bytes read. If the random access file is
42 * created in read/write mode, then output operations are also available;
43 * output operations write bytes starting at the file pointer and advance
44 * the file pointer past the bytes written. Output operations that write
45 * past the current end of the implied array cause the array to be
46 * extended. The file pointer can be read by the
47 * {@code getFilePointer} method and set by the {@code seek}
48 * method.
49 * <p>
50 * It is generally true of all the reading routines in this class that
51 * if end-of-file is reached before the desired number of bytes has been
52 * read, an {@code EOFException} (which is a kind of
53 * {@code IOException}) is thrown. If any byte cannot be read for
54 * any reason other than end-of-file, an {@code IOException} other
55 * than {@code EOFException} is thrown. In particular, an
56 * {@code IOException} may be thrown if the stream has been closed.
57 *
58 * @author unascribed
59 * @since 1.0
60 */
61
62 public class RandomAccessFile implements DataOutput, DataInput, Closeable {
63
64 private FileDescriptor fd;
65 private volatile FileChannel channel;
66 private boolean rw;
67 private boolean direct = false;
68 private int pageSize = -1;
69
70 /**
71 * The path of the referenced file
72 * (null if the stream is created with a file descriptor)
73 */
74 private final String path;
75
76 private final AtomicBoolean closed = new AtomicBoolean(false);
77
78 private static final int O_RDONLY = 1;
79 private static final int O_RDWR = 2;
80 private static final int O_SYNC = 4;
81 private static final int O_DSYNC = 8;
82 private static final int O_TEMPORARY = 16;
83 private static final int O_DIRECT = 32;
84
85 /**
86 * Creates a random access file stream to read from, and optionally
87 * to write to, a file with the specified name. A new
88 * {@link FileDescriptor} object is created to represent the
89 * connection to the file.
90 *
91 * <p> The {@code mode} argument specifies the access mode with which the
92 * file is to be opened. The permitted values and their meanings are as
93 * specified for the <a
94 * href="#mode">{@code RandomAccessFile(File,String)}</a> constructor.
95 *
96 * <p>
97 * If there is a security manager, its {@code checkRead} method
98 * is called with the {@code name} argument
99 * as its argument to see if read access to the file is allowed.
100 * If the mode allows writing, the security manager's
101 * {@code checkWrite} method
102 * is also called with the {@code name} argument
103 * as its argument to see if write access to the file is allowed.
104 *
105 * @param name the system-dependent filename
106 * @param mode the access <a href="#mode">mode</a>
107 * @exception IllegalArgumentException if the mode argument is not equal
108 * to one of {@code "r"}, {@code "rw"}, {@code "rws"}, or
109 * {@code "rwd"}
110 * @exception FileNotFoundException
111 * if the mode is {@code "r"} but the given string does not
112 * denote an existing regular file, or if the mode begins with
113 * {@code "rw"} but the given string does not denote an
114 * existing, writable regular file and a new regular file of
115 * that name cannot be created, or if some other error occurs
116 * while opening or creating the file
117 * @exception SecurityException if a security manager exists and its
118 * {@code checkRead} method denies read access to the file
119 * or the mode is {@code "rw"} and the security manager's
120 * {@code checkWrite} method denies write access to the file
121 * @see java.lang.SecurityException
122 * @see java.lang.SecurityManager#checkRead(java.lang.String)
123 * @see java.lang.SecurityManager#checkWrite(java.lang.String)
124 * @revised 1.4
125 * @spec JSR-51
126 */
127 public RandomAccessFile(String name, String mode)
128 throws FileNotFoundException
129 {
130 this(name != null ? new File(name) : null, mode);
131 }
132
133 /**
134 * Creates a random access file stream to read from, and optionally to
135 * write to, the file specified by the {@link File} argument. A new {@link
136 * FileDescriptor} object is created to represent this file connection.
137 *
138 * <p>The <a name="mode">{@code mode}</a> argument specifies the access mode
139 * in which the file is to be opened. The permitted values and their
140 * meanings are:
141 *
142 * <table summary="Access mode permitted values and meanings">
143 * <tr><th align="left">Value</th><th align="left">Meaning</th></tr>
144 * <tr><td valign="top">{@code "r"}</td>
145 * <td> Open for reading only. Invoking any of the {@code write}
146 * methods of the resulting object will cause an
147 * {@link java.io.IOException} to be thrown.</td></tr>
148 * <tr><td valign="top">{@code "rw"}</td>
149 * <td> Open for reading and writing. If the file does not already
150 * exist then an attempt will be made to create it.</td></tr>
151 * <tr><td valign="top">{@code "rws"}</td>
152 * <td> Open for reading and writing, as with {@code "rw"}, and also
153 * require that every update to the file's content or metadata be
154 * written synchronously to the underlying storage device.</td></tr>
155 * <tr><td valign="top">{@code "rwd"}</td>
156 * <td> Open for reading and writing, as with {@code "rw"}, and also
157 * require that every update to the file's content be written
158 * synchronously to the underlying storage device.</td></tr>
159 * </table>
160 *
161 * The {@code "rws"} and {@code "rwd"} modes work much like the {@link
162 * java.nio.channels.FileChannel#force(boolean) force(boolean)} method of
163 * the {@link java.nio.channels.FileChannel} class, passing arguments of
164 * {@code true} and {@code false}, respectively, except that they always
165 * apply to every I/O operation and are therefore often more efficient. If
166 * the file resides on a local storage device then when an invocation of a
167 * method of this class returns it is guaranteed that all changes made to
168 * the file by that invocation will have been written to that device. This
169 * is useful for ensuring that critical information is not lost in the
170 * event of a system crash. If the file does not reside on a local device
171 * then no such guarantee is made.
172 *
173 * <p>The {@code "rwd"} mode can be used to reduce the number of I/O
174 * operations performed. Using {@code "rwd"} only requires updates to the
175 * file's content to be written to storage; using {@code "rws"} requires
176 * updates to both the file's content and its metadata to be written, which
177 * generally requires at least one more low-level I/O operation.
178 *
179 * <p>If there is a security manager, its {@code checkRead} method is
180 * called with the pathname of the {@code file} argument as its
181 * argument to see if read access to the file is allowed. If the mode
182 * allows writing, the security manager's {@code checkWrite} method is
183 * also called with the path argument to see if write access to the file is
184 * allowed.
185 *
186 * @param file the file object
187 * @param mode the access mode, as described
188 * <a href="#mode">above</a>
189 * @exception IllegalArgumentException if the mode argument is not equal
190 * to one of {@code "r"}, {@code "rw"}, {@code "rws"}, or
191 * {@code "rwd"}
192 * @exception FileNotFoundException
193 * if the mode is {@code "r"} but the given file object does
194 * not denote an existing regular file, or if the mode begins
195 * with {@code "rw"} but the given file object does not denote
196 * an existing, writable regular file and a new regular file of
197 * that name cannot be created, or if some other error occurs
198 * while opening or creating the file
199 * @exception SecurityException if a security manager exists and its
200 * {@code checkRead} method denies read access to the file
201 * or the mode is {@code "rw"} and the security manager's
202 * {@code checkWrite} method denies write access to the file
203 * @see java.lang.SecurityManager#checkRead(java.lang.String)
204 * @see java.lang.SecurityManager#checkWrite(java.lang.String)
205 * @see java.nio.channels.FileChannel#force(boolean)
206 * @revised 1.4
207 * @spec JSR-51
208 */
209 public RandomAccessFile(File file, String mode)
210 throws FileNotFoundException
211 {
212 this(file, mode, false);
213 }
214
215 private RandomAccessFile(File file, String mode, boolean openAndDelete)
216 throws FileNotFoundException
217 {
218 String name = (file != null ? file.getPath() : null);
219 int imode = -1;
220 if (mode.equals("r"))
221 imode = O_RDONLY;
222 else if (mode.equals("ro")) {
223 imode = O_RDONLY | O_DIRECT;
224 direct = true;
225 getPageSize();
226 }
227 else if (mode.startsWith("rw")) {
228 imode = O_RDWR;
229 rw = true;
230 if (mode.length() > 2) {
231 if (mode.equals("rws"))
232 imode |= O_SYNC;
233 else if (mode.equals("rwd"))
234 imode |= O_DSYNC;
235 else if (mode.equals("rwo")) {
236 imode |= O_DIRECT;
237 direct = true;
238 getPageSize();
239 }
240 else
241 imode = -1;
242 }
243 }
244 if (openAndDelete)
245 imode |= O_TEMPORARY;
246 if (imode < 0)
247 throw new IllegalArgumentException("Illegal mode \"" + mode
248 + "\" must be one of "
249 + "\"r\", \"ro\", \"rw\", \"rws\", \"rwd\""
250 + " or \"rwo\"");
251 SecurityManager security = System.getSecurityManager();
252 if (security != null) {
253 security.checkRead(name);
254 if (rw) {
255 security.checkWrite(name);
256 }
257 }
258 if (name == null) {
259 throw new NullPointerException();
260 }
261 if (file.isInvalid()) {
262 throw new FileNotFoundException("Invalid file path");
263 }
264 fd = new FileDescriptor();
265 fd.attach(this);
266 path = name;
267 open(name, imode);
268 }
269
270 /**
271 * Returns the opaque file descriptor object associated with this
272 * stream.
273 *
274 * @return the file descriptor object associated with this stream.
275 * @exception IOException if an I/O error occurs.
276 * @see java.io.FileDescriptor
277 */
278 public final FileDescriptor getFD() throws IOException {
279 if (fd != null) {
280 return fd;
281 }
282 throw new IOException();
283 }
284
285 /**
286 * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
287 * object associated with this file.
288 *
289 * <p> The {@link java.nio.channels.FileChannel#position()
290 * position} of the returned channel will always be equal to
291 * this object's file-pointer offset as returned by the {@link
292 * #getFilePointer getFilePointer} method. Changing this object's
293 * file-pointer offset, whether explicitly or by reading or writing bytes,
294 * will change the position of the channel, and vice versa. Changing the
295 * file's length via this object will change the length seen via the file
296 * channel, and vice versa.
297 *
298 * @return the file channel associated with this file
299 *
300 * @since 1.4
301 * @spec JSR-51
302 */
303 public final FileChannel getChannel() {
304 FileChannel fc = this.channel;
305 if (fc == null) {
306 synchronized (this) {
307 fc = this.channel;
308 if (fc == null) {
309 this.channel = fc = FileChannelImpl.open(fd, path, true, rw, this);
310 if (closed.get()) {
311 try {
312 fc.close();
313 } catch (IOException ioe) {
314 throw new InternalError(ioe); // should not happen
315 }
316 }
317 }
318 }
319 }
320 return fc;
321 }
322
323 /**
324 * Opens a file and returns the file descriptor. The file is
325 * opened in read-write mode if the O_RDWR bit in {@code mode}
326 * is true, else the file is opened as read-only.
327 * If the {@code name} refers to a directory, an IOException
328 * is thrown.
329 *
330 * @param name the name of the file
331 * @param mode the mode flags, a combination of the O_ constants
332 * defined above
333 */
334 private native void open0(String name, int mode)
335 throws FileNotFoundException;
336
337 // wrap native call to allow instrumentation
338 /**
339 * Opens a file and returns the file descriptor. The file is
340 * opened in read-write mode if the O_RDWR bit in {@code mode}
341 * is true, else the file is opened as read-only.
342 * If the {@code name} refers to a directory, an IOException
343 * is thrown.
344 *
345 * @param name the name of the file
346 * @param mode the mode flags, a combination of the O_ constants
347 * defined above
348 */
349 private void open(String name, int mode)
350 throws FileNotFoundException {
351 open0(name, mode);
352 }
353
354 private native int getPageSize0();
355
356 private int getPageSize() {
357 if (pageSize == -1) {
358 pageSize = getPageSize0();
359 }
360 return this.pageSize;
361 }
362
363 // 'Read' primitives
364
365 /**
366 * Reads a byte of data from this file. The byte is returned as an
367 * integer in the range 0 to 255 ({@code 0x00-0x0ff}). This
368 * method blocks if no input is yet available.
369 * <p>
370 * Although {@code RandomAccessFile} is not a subclass of
371 * {@code InputStream}, this method behaves in exactly the same
372 * way as the {@link InputStream#read()} method of
373 * {@code InputStream}.
374 *
375 * @return the next byte of data, or {@code -1} if the end of the
376 * file has been reached.
377 * @exception IOException if an I/O error occurs. Not thrown if
378 * end-of-file has been reached.
379 */
380 public int read() throws IOException {
381 return read0();
382 }
383
384 private native int read0() throws IOException;
385
386 /**
387 * Reads a sub array as a sequence of bytes.
388 * @param b the buffer into which the data is read.
389 * @param off the start offset of the data.
390 * @param len the number of bytes to read.
391 * @exception IOException If an I/O error has occurred.
392 */
393 private native int readBytes(byte b[], int off, int len) throws IOException;
394
395 /**
396 * Reads a sub array as a sequence of bytes with DirectIO.
397 * @param b the buffer into which the data is read.
398 * @param off the start offset of the data.
399 * @param len the number of bytes to read.
400 * @exception IOException If an I/O error has occurred.
401 */
402 private native int readBytesD(byte b[], int off, int len) throws IOException;
403
404 /**
405 * Reads up to {@code len} bytes of data from this file into an
406 * array of bytes. This method blocks until at least one byte of input
407 * is available.
408 * <p>
409 * Although {@code RandomAccessFile} is not a subclass of
410 * {@code InputStream}, this method behaves in exactly the
411 * same way as the {@link InputStream#read(byte[], int, int)} method of
412 * {@code InputStream}.
413 *
414 * @param b the buffer into which the data is read.
415 * @param off the start offset in array {@code b}
416 * at which the data is written.
417 * @param len the maximum number of bytes read.
418 * @return the total number of bytes read into the buffer, or
419 * {@code -1} if there is no more data because the end of
420 * the file has been reached.
421 * @exception IOException If the first byte cannot be read for any reason
422 * other than end of file, or if the random access file has been closed, or if
423 * some other I/O error occurs.
424 * @exception NullPointerException If {@code b} is {@code null}.
425 * @exception IndexOutOfBoundsException If {@code off} is negative,
426 * {@code len} is negative, or {@code len} is greater than
427 * {@code b.length - off}
428 */
429 public int read(byte b[], int off, int len) throws IOException {
430 if (direct) {
431 return readBytesD(b, off, len);
432 }
433 return readBytes(b, off, len);
434 }
435
436 /**
437 * Reads up to {@code b.length} bytes of data from this file
438 * into an array of bytes. This method blocks until at least one byte
439 * of input is available.
440 * <p>
441 * Although {@code RandomAccessFile} is not a subclass of
442 * {@code InputStream}, this method behaves in exactly the
443 * same way as the {@link InputStream#read(byte[])} method of
444 * {@code InputStream}.
445 *
446 * @param b the buffer into which the data is read.
447 * @return the total number of bytes read into the buffer, or
448 * {@code -1} if there is no more data because the end of
449 * this file has been reached.
450 * @exception IOException If the first byte cannot be read for any reason
451 * other than end of file, or if the random access file has been closed, or if
452 * some other I/O error occurs.
453 * @exception NullPointerException If {@code b} is {@code null}.
454 */
455 public int read(byte b[]) throws IOException {
456 if (direct) {
457 return readBytesD(b, 0, b.length);
458 }
459 return readBytes(b, 0, b.length);
460 }
461
462 /**
463 * Reads {@code b.length} bytes from this file into the byte
464 * array, starting at the current file pointer. This method reads
465 * repeatedly from the file until the requested number of bytes are
466 * read. This method blocks until the requested number of bytes are
467 * read, the end of the stream is detected, or an exception is thrown.
468 *
469 * @param b the buffer into which the data is read.
470 * @throws NullPointerException if {@code b} is {@code null}.
471 * @throws EOFException if this file reaches the end before reading
472 * all the bytes.
473 * @throws IOException if an I/O error occurs.
474 */
475 public final void readFully(byte b[]) throws IOException {
476 readFully(b, 0, b.length);
477 }
478
479 /**
480 * Reads exactly {@code len} bytes from this file into the byte
481 * array, starting at the current file pointer. This method reads
482 * repeatedly from the file until the requested number of bytes are
483 * read. This method blocks until the requested number of bytes are
484 * read, the end of the stream is detected, or an exception is thrown.
485 *
486 * @param b the buffer into which the data is read.
487 * @param off the start offset into the data array {@code b}.
488 * @param len the number of bytes to read.
489 * @throws NullPointerException if {@code b} is {@code null}.
490 * @throws IndexOutOfBoundsException if {@code off} is negative,
491 * {@code len} is negative, or {@code len} is greater than
492 * {@code b.length - off}.
493 * @throws EOFException if this file reaches the end before reading
494 * all the bytes.
495 * @throws IOException if an I/O error occurs.
496 */
497 public final void readFully(byte b[], int off, int len) throws IOException {
498 int n = 0;
499 do {
500 int count = this.read(b, off + n, len - n);
501 if (count < 0)
502 throw new EOFException();
503 n += count;
504 } while (n < len);
505 }
506
507 /**
508 * Attempts to skip over {@code n} bytes of input discarding the
509 * skipped bytes.
510 * <p>
511 *
512 * This method may skip over some smaller number of bytes, possibly zero.
513 * This may result from any of a number of conditions; reaching end of
514 * file before {@code n} bytes have been skipped is only one
515 * possibility. This method never throws an {@code EOFException}.
516 * The actual number of bytes skipped is returned. If {@code n}
517 * is negative, no bytes are skipped.
518 *
519 * @param n the number of bytes to be skipped.
520 * @return the actual number of bytes skipped.
521 * @exception IOException if an I/O error occurs.
522 */
523 public int skipBytes(int n) throws IOException {
524 long pos;
525 long len;
526 long newpos;
527
528 if (n <= 0) {
529 return 0;
530 }
531 pos = getFilePointer();
532 len = length();
533 newpos = pos + n;
534 if (newpos > len) {
535 newpos = len;
536 }
537 seek(newpos);
538
539 /* return the actual number of bytes skipped */
540 return (int) (newpos - pos);
541 }
542
543 // 'Write' primitives
544
545 /**
546 * Writes the specified byte to this file. The write starts at
547 * the current file pointer.
548 *
549 * @param b the {@code byte} to be written.
550 * @exception IOException if an I/O error occurs.
551 */
552 public void write(int b) throws IOException {
553 write0(b);
554 }
555
556 private native void write0(int b) throws IOException;
557
558 /**
559 * Writes a sub array as a sequence of bytes.
560 * @param b the data to be written
561
562 * @param off the start offset in the data
563 * @param len the number of bytes that are written
564 * @exception IOException If an I/O error has occurred.
565 */
566 private native void writeBytes(byte b[], int off, int len) throws IOException;
567
568 /**
569 * Writes a sub array as a sequence of bytes with DirectIO.
570 * @param b the data to be written
571 * @param off the start offset in the data
572 * @param len the number of bytes that are written
573 * @exception IOException If an I/O error has occurred.
574 */
575 private native void writeBytesD(byte b[], int off, int len) throws IOException;
576
577 /**
578 * Writes {@code b.length} bytes from the specified byte array
579 * to this file, starting at the current file pointer.
580 *
581 * @param b the data.
582 * @exception IOException if an I/O error occurs.
583 */
584 public void write(byte b[]) throws IOException {
585 if (direct) {
586 if((b.length % pageSize != 0) && (getCurrentLocation() % pageSize != 0)) {
587 throw new IOException("In DirectIO mode, the IO size and start point "
588 + "must be aligned with kernel page size " + pageSize + " bytes!");
589 } else {
590 writeBytesD(b, 0, b.length);
591 }
592 } else {
593 writeBytes(b, 0, b.length);
594 }
595 }
596
597 /**
598 * Writes {@code len} bytes from the specified byte array
599 * starting at offset {@code off} to this file.
600 *
601 * @param b the data.
602 * @param off the start offset in the data.
603 * @param len the number of bytes to write.
604 * @exception IOException if an I/O error occurs.
605 */
606 public void write(byte b[], int off, int len) throws IOException {
607 if (direct) {
608 if ((len % pageSize != 0) || (getCurrentLocation() % pageSize != 0)) {
609 throw new IOException("In DirectIO mode, the IO size and start point "
610 + "must be aligned with kernel page size " + pageSize + " bytes!");
611 } else {
612 writeBytesD(b, off, len);
613 }
614 } else {
615 writeBytes(b, off, len);
616 }
617 }
618
619 // 'Random access' stuff
620
621 /**
622 * Returns the current offset in this file.
623 *
624 * @return the offset from the beginning of the file, in bytes,
625 * at which the next read or write occurs.
626 * @exception IOException if an I/O error occurs.
627 */
628 public native long getFilePointer() throws IOException;
629
630 /**
631 * Sets the file-pointer offset, measured from the beginning of this
632 * file, at which the next read or write occurs. The offset may be
633 * set beyond the end of the file. Setting the offset beyond the end
634 * of the file does not change the file length. The file length will
635 * change only by writing after the offset has been set beyond the end
636 * of the file.
637 *
638 * @param pos the offset position, measured in bytes from the
639 * beginning of the file, at which to set the file
640 * pointer.
641 * @exception IOException if {@code pos} is less than
642 * {@code 0} or if an I/O error occurs.
643 */
644 public void seek(long pos) throws IOException {
645 if (pos < 0) {
646 throw new IOException("Negative seek offset");
647 } else {
648 seek0(pos);
649 }
650 }
651
652 private native void seek0(long pos) throws IOException;
653
654 private long getCurrentLocation() throws IOException {
655 return getCurrentLocation0();
656 }
657
658 private native long getCurrentLocation0() throws IOException;
659
660 /**
661 * Returns the length of this file.
662 *
663 * @return the length of this file, measured in bytes.
664 * @exception IOException if an I/O error occurs.
665 */
666 public native long length() throws IOException;
667
668 /**
669 * Sets the length of this file.
670 *
671 * <p> If the present length of the file as returned by the
672 * {@code length} method is greater than the {@code newLength}
673 * argument then the file will be truncated. In this case, if the file
674 * offset as returned by the {@code getFilePointer} method is greater
675 * than {@code newLength} then after this method returns the offset
676 * will be equal to {@code newLength}.
677 *
678 * <p> If the present length of the file as returned by the
679 * {@code length} method is smaller than the {@code newLength}
680 * argument then the file will be extended. In this case, the contents of
681 * the extended portion of the file are not defined.
682 *
683 * @param newLength The desired length of the file
684 * @exception IOException If an I/O error occurs
685 * @since 1.2
686 */
687 public native void setLength(long newLength) throws IOException;
688
689 /**
690 * Closes this random access file stream and releases any system
691 * resources associated with the stream. A closed random access
692 * file cannot perform input or output operations and cannot be
693 * reopened.
694 *
695 * <p> If this file has an associated channel then the channel is closed
696 * as well.
697 *
698 * @exception IOException if an I/O error occurs.
699 *
700 * @revised 1.4
701 * @spec JSR-51
702 */
703 public void close() throws IOException {
704 if (!closed.compareAndSet(false, true)) {
705 // if compareAndSet() returns false closed was already true
706 return;
707 }
708
709 FileChannel fc = channel;
710 if (fc != null) {
711 fc.close();
712 }
713
714 fd.closeAll(new Closeable() {
715 public void close() throws IOException {
716 close0();
717 }
718 });
719 }
720
721 //
722 // Some "reading/writing Java data types" methods stolen from
723 // DataInputStream and DataOutputStream.
724 //
725
726 /**
727 * Reads a {@code boolean} from this file. This method reads a
728 * single byte from the file, starting at the current file pointer.
729 * A value of {@code 0} represents
730 * {@code false}. Any other value represents {@code true}.
731 * This method blocks until the byte is read, the end of the stream
732 * is detected, or an exception is thrown.
733 *
734 * @return the {@code boolean} value read.
735 * @exception EOFException if this file has reached the end.
736 * @exception IOException if an I/O error occurs.
737 */
738 public final boolean readBoolean() throws IOException {
739 int ch = this.read();
740 if (ch < 0)
741 throw new EOFException();
742 return (ch != 0);
743 }
744
745 /**
746 * Reads a signed eight-bit value from this file. This method reads a
747 * byte from the file, starting from the current file pointer.
748 * If the byte read is {@code b}, where
749 * <code>0 <= b <= 255</code>,
750 * then the result is:
751 * <blockquote><pre>
752 * (byte)(b)
753 * </pre></blockquote>
754 * <p>
755 * This method blocks until the byte is read, the end of the stream
756 * is detected, or an exception is thrown.
757 *
758 * @return the next byte of this file as a signed eight-bit
759 * {@code byte}.
760 * @exception EOFException if this file has reached the end.
761 * @exception IOException if an I/O error occurs.
762 */
763 public final byte readByte() throws IOException {
764 int ch = this.read();
765 if (ch < 0)
766 throw new EOFException();
767 return (byte)(ch);
768 }
769
770 /**
771 * Reads an unsigned eight-bit number from this file. This method reads
772 * a byte from this file, starting at the current file pointer,
773 * and returns that byte.
774 * <p>
775 * This method blocks until the byte is read, the end of the stream
776 * is detected, or an exception is thrown.
777 *
778 * @return the next byte of this file, interpreted as an unsigned
779 * eight-bit number.
780 * @exception EOFException if this file has reached the end.
781 * @exception IOException if an I/O error occurs.
782 */
783 public final int readUnsignedByte() throws IOException {
784 int ch = this.read();
785 if (ch < 0)
786 throw new EOFException();
787 return ch;
788 }
789
790 /**
791 * Reads a signed 16-bit number from this file. The method reads two
792 * bytes from this file, starting at the current file pointer.
793 * If the two bytes read, in order, are
794 * {@code b1} and {@code b2}, where each of the two values is
795 * between {@code 0} and {@code 255}, inclusive, then the
796 * result is equal to:
797 * <blockquote><pre>
798 * (short)((b1 << 8) | b2)
799 * </pre></blockquote>
800 * <p>
801 * This method blocks until the two bytes are read, the end of the
802 * stream is detected, or an exception is thrown.
803 *
804 * @return the next two bytes of this file, interpreted as a signed
805 * 16-bit number.
806 * @exception EOFException if this file reaches the end before reading
807 * two bytes.
808 * @exception IOException if an I/O error occurs.
809 */
810 public final short readShort() throws IOException {
811 int ch1 = this.read();
812 int ch2 = this.read();
813 if ((ch1 | ch2) < 0)
814 throw new EOFException();
815 return (short)((ch1 << 8) + (ch2 << 0));
816 }
817
818 /**
819 * Reads an unsigned 16-bit number from this file. This method reads
820 * two bytes from the file, starting at the current file pointer.
821 * If the bytes read, in order, are
822 * {@code b1} and {@code b2}, where
823 * <code>0 <= b1, b2 <= 255</code>,
824 * then the result is equal to:
825 * <blockquote><pre>
826 * (b1 << 8) | b2
827 * </pre></blockquote>
828 * <p>
829 * This method blocks until the two bytes are read, the end of the
830 * stream is detected, or an exception is thrown.
831 *
832 * @return the next two bytes of this file, interpreted as an unsigned
833 * 16-bit integer.
834 * @exception EOFException if this file reaches the end before reading
835 * two bytes.
836 * @exception IOException if an I/O error occurs.
837 */
838 public final int readUnsignedShort() throws IOException {
839 int ch1 = this.read();
840 int ch2 = this.read();
841 if ((ch1 | ch2) < 0)
842 throw new EOFException();
843 return (ch1 << 8) + (ch2 << 0);
844 }
845
846 /**
847 * Reads a character from this file. This method reads two
848 * bytes from the file, starting at the current file pointer.
849 * If the bytes read, in order, are
850 * {@code b1} and {@code b2}, where
851 * <code>0 <= b1, b2 <= 255</code>,
852 * then the result is equal to:
853 * <blockquote><pre>
854 * (char)((b1 << 8) | b2)
855 * </pre></blockquote>
856 * <p>
857 * This method blocks until the two bytes are read, the end of the
858 * stream is detected, or an exception is thrown.
859 *
860 * @return the next two bytes of this file, interpreted as a
861 * {@code char}.
862 * @exception EOFException if this file reaches the end before reading
863 * two bytes.
864 * @exception IOException if an I/O error occurs.
865 */
866 public final char readChar() throws IOException {
867 int ch1 = this.read();
868 int ch2 = this.read();
869 if ((ch1 | ch2) < 0)
870 throw new EOFException();
871 return (char)((ch1 << 8) + (ch2 << 0));
872 }
873
874 /**
875 * Reads a signed 32-bit integer from this file. This method reads 4
876 * bytes from the file, starting at the current file pointer.
877 * If the bytes read, in order, are {@code b1},
878 * {@code b2}, {@code b3}, and {@code b4}, where
879 * <code>0 <= b1, b2, b3, b4 <= 255</code>,
880 * then the result is equal to:
881 * <blockquote><pre>
882 * (b1 << 24) | (b2 << 16) + (b3 << 8) + b4
883 * </pre></blockquote>
884 * <p>
885 * This method blocks until the four bytes are read, the end of the
886 * stream is detected, or an exception is thrown.
887 *
888 * @return the next four bytes of this file, interpreted as an
889 * {@code int}.
890 * @exception EOFException if this file reaches the end before reading
891 * four bytes.
892 * @exception IOException if an I/O error occurs.
893 */
894 public final int readInt() throws IOException {
895 int ch1 = this.read();
896 int ch2 = this.read();
897 int ch3 = this.read();
898 int ch4 = this.read();
899 if ((ch1 | ch2 | ch3 | ch4) < 0)
900 throw new EOFException();
901 return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
902 }
903
904 /**
905 * Reads a signed 64-bit integer from this file. This method reads eight
906 * bytes from the file, starting at the current file pointer.
907 * If the bytes read, in order, are
908 * {@code b1}, {@code b2}, {@code b3},
909 * {@code b4}, {@code b5}, {@code b6},
910 * {@code b7}, and {@code b8,} where:
911 * <blockquote><pre>
912 * 0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,
913 * </pre></blockquote>
914 * <p>
915 * then the result is equal to:
916 * <blockquote><pre>
917 * ((long)b1 << 56) + ((long)b2 << 48)
918 * + ((long)b3 << 40) + ((long)b4 << 32)
919 * + ((long)b5 << 24) + ((long)b6 << 16)
920 * + ((long)b7 << 8) + b8
921 * </pre></blockquote>
922 * <p>
923 * This method blocks until the eight bytes are read, the end of the
924 * stream is detected, or an exception is thrown.
925 *
926 * @return the next eight bytes of this file, interpreted as a
927 * {@code long}.
928 * @exception EOFException if this file reaches the end before reading
929 * eight bytes.
930 * @exception IOException if an I/O error occurs.
931 */
932 public final long readLong() throws IOException {
933 return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
934 }
935
936 /**
937 * Reads a {@code float} from this file. This method reads an
938 * {@code int} value, starting at the current file pointer,
939 * as if by the {@code readInt} method
940 * and then converts that {@code int} to a {@code float}
941 * using the {@code intBitsToFloat} method in class
942 * {@code Float}.
943 * <p>
944 * This method blocks until the four bytes are read, the end of the
945 * stream is detected, or an exception is thrown.
946 *
947 * @return the next four bytes of this file, interpreted as a
948 * {@code float}.
949 * @exception EOFException if this file reaches the end before reading
950 * four bytes.
951 * @exception IOException if an I/O error occurs.
952 * @see java.io.RandomAccessFile#readInt()
953 * @see java.lang.Float#intBitsToFloat(int)
954 */
955 public final float readFloat() throws IOException {
956 return Float.intBitsToFloat(readInt());
957 }
958
959 /**
960 * Reads a {@code double} from this file. This method reads a
961 * {@code long} value, starting at the current file pointer,
962 * as if by the {@code readLong} method
963 * and then converts that {@code long} to a {@code double}
964 * using the {@code longBitsToDouble} method in
965 * class {@code Double}.
966 * <p>
967 * This method blocks until the eight bytes are read, the end of the
968 * stream is detected, or an exception is thrown.
969 *
970 * @return the next eight bytes of this file, interpreted as a
971 * {@code double}.
972 * @exception EOFException if this file reaches the end before reading
973 * eight bytes.
974 * @exception IOException if an I/O error occurs.
975 * @see java.io.RandomAccessFile#readLong()
976 * @see java.lang.Double#longBitsToDouble(long)
977 */
978 public final double readDouble() throws IOException {
979 return Double.longBitsToDouble(readLong());
980 }
981
982 /**
983 * Reads the next line of text from this file. This method successively
984 * reads bytes from the file, starting at the current file pointer,
985 * until it reaches a line terminator or the end
986 * of the file. Each byte is converted into a character by taking the
987 * byte's value for the lower eight bits of the character and setting the
988 * high eight bits of the character to zero. This method does not,
989 * therefore, support the full Unicode character set.
990 *
991 * <p> A line of text is terminated by a carriage-return character
992 * ({@code '\u005Cr'}), a newline character ({@code '\u005Cn'}), a
993 * carriage-return character immediately followed by a newline character,
994 * or the end of the file. Line-terminating characters are discarded and
995 * are not included as part of the string returned.
996 *
997 * <p> This method blocks until a newline character is read, a carriage
998 * return and the byte following it are read (to see if it is a newline),
999 * the end of the file is reached, or an exception is thrown.
1000 *
1001 * @return the next line of text from this file, or null if end
1002 * of file is encountered before even one byte is read.
1003 * @exception IOException if an I/O error occurs.
1004 */
1005
1006 public final String readLine() throws IOException {
1007 StringBuilder input = new StringBuilder();
1008 int c = -1;
1009 boolean eol = false;
1010
1011 while (!eol) {
1012 switch (c = read()) {
1013 case -1:
1014 case '\n':
1015 eol = true;
1016 break;
1017 case '\r':
1018 eol = true;
1019 long cur = getFilePointer();
1020 if ((read()) != '\n') {
1021 seek(cur);
1022 }
1023 break;
1024 default:
1025 input.append((char)c);
1026 break;
1027 }
1028 }
1029
1030 if ((c == -1) && (input.length() == 0)) {
1031 return null;
1032 }
1033 return input.toString();
1034 }
1035
1036 /**
1037 * Reads in a string from this file. The string has been encoded
1038 * using a
1039 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
1040 * format.
1041 * <p>
1042 * The first two bytes are read, starting from the current file
1043 * pointer, as if by
1044 * {@code readUnsignedShort}. This value gives the number of
1045 * following bytes that are in the encoded string, not
1046 * the length of the resulting string. The following bytes are then
1047 * interpreted as bytes encoding characters in the modified UTF-8 format
1048 * and are converted into characters.
1049 * <p>
1050 * This method blocks until all the bytes are read, the end of the
1051 * stream is detected, or an exception is thrown.
1052 *
1053 * @return a Unicode string.
1054 * @exception EOFException if this file reaches the end before
1055 * reading all the bytes.
1056 * @exception IOException if an I/O error occurs.
1057 * @exception UTFDataFormatException if the bytes do not represent
1058 * valid modified UTF-8 encoding of a Unicode string.
1059 * @see java.io.RandomAccessFile#readUnsignedShort()
1060 */
1061 public final String readUTF() throws IOException {
1062 return DataInputStream.readUTF(this);
1063 }
1064
1065 /**
1066 * Writes a {@code boolean} to the file as a one-byte value. The
1067 * value {@code true} is written out as the value
1068 * {@code (byte)1}; the value {@code false} is written out
1069 * as the value {@code (byte)0}. The write starts at
1070 * the current position of the file pointer.
1071 *
1072 * @param v a {@code boolean} value to be written.
1073 * @exception IOException if an I/O error occurs.
1074 */
1075 public final void writeBoolean(boolean v) throws IOException {
1076 write(v ? 1 : 0);
1077 //written++;
1078 }
1079
1080 /**
1081 * Writes a {@code byte} to the file as a one-byte value. The
1082 * write starts at the current position of the file pointer.
1083 *
1084 * @param v a {@code byte} value to be written.
1085 * @exception IOException if an I/O error occurs.
1086 */
1087 public final void writeByte(int v) throws IOException {
1088 write(v);
1089 //written++;
1090 }
1091
1092 /**
1093 * Writes a {@code short} to the file as two bytes, high byte first.
1094 * The write starts at the current position of the file pointer.
1095 *
1096 * @param v a {@code short} to be written.
1097 * @exception IOException if an I/O error occurs.
1098 */
1099 public final void writeShort(int v) throws IOException {
1100 write((v >>> 8) & 0xFF);
1101 write((v >>> 0) & 0xFF);
1102 //written += 2;
1103 }
1104
1105 /**
1106 * Writes a {@code char} to the file as a two-byte value, high
1107 * byte first. The write starts at the current position of the
1108 * file pointer.
1109 *
1110 * @param v a {@code char} value to be written.
1111 * @exception IOException if an I/O error occurs.
1112 */
1113 public final void writeChar(int v) throws IOException {
1114 write((v >>> 8) & 0xFF);
1115 write((v >>> 0) & 0xFF);
1116 //written += 2;
1117 }
1118
1119 /**
1120 * Writes an {@code int} to the file as four bytes, high byte first.
1121 * The write starts at the current position of the file pointer.
1122 *
1123 * @param v an {@code int} to be written.
1124 * @exception IOException if an I/O error occurs.
1125 */
1126 public final void writeInt(int v) throws IOException {
1127 write((v >>> 24) & 0xFF);
1128 write((v >>> 16) & 0xFF);
1129 write((v >>> 8) & 0xFF);
1130 write((v >>> 0) & 0xFF);
1131 //written += 4;
1132 }
1133
1134 /**
1135 * Writes a {@code long} to the file as eight bytes, high byte first.
1136 * The write starts at the current position of the file pointer.
1137 *
1138 * @param v a {@code long} to be written.
1139 * @exception IOException if an I/O error occurs.
1140 */
1141 public final void writeLong(long v) throws IOException {
1142 write((int)(v >>> 56) & 0xFF);
1143 write((int)(v >>> 48) & 0xFF);
1144 write((int)(v >>> 40) & 0xFF);
1145 write((int)(v >>> 32) & 0xFF);
1146 write((int)(v >>> 24) & 0xFF);
1147 write((int)(v >>> 16) & 0xFF);
1148 write((int)(v >>> 8) & 0xFF);
1149 write((int)(v >>> 0) & 0xFF);
1150 //written += 8;
1151 }
1152
1153 /**
1154 * Converts the float argument to an {@code int} using the
1155 * {@code floatToIntBits} method in class {@code Float},
1156 * and then writes that {@code int} value to the file as a
1157 * four-byte quantity, high byte first. The write starts at the
1158 * current position of the file pointer.
1159 *
1160 * @param v a {@code float} value to be written.
1161 * @exception IOException if an I/O error occurs.
1162 * @see java.lang.Float#floatToIntBits(float)
1163 */
1164 public final void writeFloat(float v) throws IOException {
1165 writeInt(Float.floatToIntBits(v));
1166 }
1167
1168 /**
1169 * Converts the double argument to a {@code long} using the
1170 * {@code doubleToLongBits} method in class {@code Double},
1171 * and then writes that {@code long} value to the file as an
1172 * eight-byte quantity, high byte first. The write starts at the current
1173 * position of the file pointer.
1174 *
1175 * @param v a {@code double} value to be written.
1176 * @exception IOException if an I/O error occurs.
1177 * @see java.lang.Double#doubleToLongBits(double)
1178 */
1179 public final void writeDouble(double v) throws IOException {
1180 writeLong(Double.doubleToLongBits(v));
1181 }
1182
1183 /**
1184 * Writes the string to the file as a sequence of bytes. Each
1185 * character in the string is written out, in sequence, by discarding
1186 * its high eight bits. The write starts at the current position of
1187 * the file pointer.
1188 *
1189 * @param s a string of bytes to be written.
1190 * @exception IOException if an I/O error occurs.
1191 */
1192 @SuppressWarnings("deprecation")
1193 public final void writeBytes(String s) throws IOException {
1194 int len = s.length();
1195 byte[] b = new byte[len];
1196 s.getBytes(0, len, b, 0);
1197 writeBytes(b, 0, len);
1198 }
1199
1200 /**
1201 * Writes a string to the file as a sequence of characters. Each
1202 * character is written to the data output stream as if by the
1203 * {@code writeChar} method. The write starts at the current
1204 * position of the file pointer.
1205 *
1206 * @param s a {@code String} value to be written.
1207 * @exception IOException if an I/O error occurs.
1208 * @see java.io.RandomAccessFile#writeChar(int)
1209 */
1210 public final void writeChars(String s) throws IOException {
1211 int clen = s.length();
1212 int blen = 2*clen;
1213 byte[] b = new byte[blen];
1214 char[] c = new char[clen];
1215 s.getChars(0, clen, c, 0);
1216 for (int i = 0, j = 0; i < clen; i++) {
1217 b[j++] = (byte)(c[i] >>> 8);
1218 b[j++] = (byte)(c[i] >>> 0);
1219 }
1220 writeBytes(b, 0, blen);
1221 }
1222
1223 /**
1224 * Writes a string to the file using
1225 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
1226 * encoding in a machine-independent manner.
1227 * <p>
1228 * First, two bytes are written to the file, starting at the
1229 * current file pointer, as if by the
1230 * {@code writeShort} method giving the number of bytes to
1231 * follow. This value is the number of bytes actually written out,
1232 * not the length of the string. Following the length, each character
1233 * of the string is output, in sequence, using the modified UTF-8 encoding
1234 * for each character.
1235 *
1236 * @param str a string to be written.
1237 * @exception IOException if an I/O error occurs.
1238 */
1239 public final void writeUTF(String str) throws IOException {
1240 DataOutputStream.writeUTF(str, this);
1241 }
1242
1243 private static native void initIDs();
1244
1245 private native void close0() throws IOException;
1246
1247 static {
1248 initIDs();
1249 SharedSecrets.setJavaIORandomAccessFileAccess(new JavaIORandomAccessFileAccess()
1250 {
1251 // This is for j.u.z.ZipFile.OPEN_DELETE. The O_TEMPORARY flag
1252 // is only implemented/supported on windows.
1253 public RandomAccessFile openAndDelete(File file, String mode)
1254 throws IOException
1255 {
1256 return new RandomAccessFile(file, mode, true);
1257 }
1258 });
1259 }
1260 }