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| 1 | /* | ||
| 2 | * Copyright (c) 1994, 2007, 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 sun.nio.ch.FileChannelImpl; | ||
| 30 | |||
| 31 | |||
| 32 | /** | ||
| 33 | * Instances of this class support both reading and writing to a | ||
| 34 | * random access file. A random access file behaves like a large | ||
| 35 | * array of bytes stored in the file system. There is a kind of cursor, | ||
| 36 | * or index into the implied array, called the <em>file pointer</em>; | ||
| 37 | * input operations read bytes starting at the file pointer and advance | ||
| 38 | * the file pointer past the bytes read. If the random access file is | ||
| 39 | * created in read/write mode, then output operations are also available; | ||
| 40 | * output operations write bytes starting at the file pointer and advance | ||
| 41 | * the file pointer past the bytes written. Output operations that write | ||
| 42 | * past the current end of the implied array cause the array to be | ||
| 43 | * extended. The file pointer can be read by the | ||
| 44 | * <code>getFilePointer</code> method and set by the <code>seek</code> | ||
| 45 | * method. | ||
| 46 | * <p> | ||
| 47 | * It is generally true of all the reading routines in this class that | ||
| 48 | * if end-of-file is reached before the desired number of bytes has been | ||
| 49 | * read, an <code>EOFException</code> (which is a kind of | ||
| 50 | * <code>IOException</code>) is thrown. If any byte cannot be read for | ||
| 51 | * any reason other than end-of-file, an <code>IOException</code> other | ||
| 52 | * than <code>EOFException</code> is thrown. In particular, an | ||
| 53 | * <code>IOException</code> may be thrown if the stream has been closed. | ||
| 54 | * | ||
| 55 | * @author unascribed | ||
| 56 | * @since JDK1.0 | ||
| 57 | */ | ||
| 58 | |||
| 59 | public class RandomAccessFile implements DataOutput, DataInput, Closeable { | ||
| 60 | |||
| 61 | private FileDescriptor fd; | ||
| 62 | private FileChannel channel = null; | ||
| 63 | private boolean rw; | ||
| 64 | |||
| 65 | private Object closeLock = new Object(); | ||
| 66 | private volatile boolean closed = false; | ||
| 67 | |||
| 68 | private static final int O_RDONLY = 1; | ||
| 69 | private static final int O_RDWR = 2; | ||
| 70 | private static final int O_SYNC = 4; | ||
| 71 | private static final int O_DSYNC = 8; | ||
| 72 | |||
| 73 | /** | ||
| 74 | * Creates a random access file stream to read from, and optionally | ||
| 75 | * to write to, a file with the specified name. A new | ||
| 76 | * {@link FileDescriptor} object is created to represent the | ||
| 77 | * connection to the file. | ||
| 78 | * | ||
| 79 | * <p> The <tt>mode</tt> argument specifies the access mode with which the | ||
| 80 | * file is to be opened. The permitted values and their meanings are as | ||
| 81 | * specified for the <a | ||
| 82 | * href="#mode"><tt>RandomAccessFile(File,String)</tt></a> constructor. | ||
| 83 | * | ||
| 84 | * <p> | ||
| 85 | * If there is a security manager, its <code>checkRead</code> method | ||
| 86 | * is called with the <code>name</code> argument | ||
| 87 | * as its argument to see if read access to the file is allowed. | ||
| 88 | * If the mode allows writing, the security manager's | ||
| 89 | * <code>checkWrite</code> method | ||
| 90 | * is also called with the <code>name</code> argument | ||
| 91 | * as its argument to see if write access to the file is allowed. | ||
| 92 | * | ||
| 93 | * @param name the system-dependent filename | ||
| 94 | * @param mode the access <a href="#mode">mode</a> | ||
| 95 | * @exception IllegalArgumentException if the mode argument is not equal | ||
| 96 | * to one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or | ||
| 97 | * <tt>"rwd"</tt> | ||
| 98 | * @exception FileNotFoundException | ||
| 99 | * if the mode is <tt>"r"</tt> but the given string does not | ||
| 100 | * denote an existing regular file, or if the mode begins with | ||
| 101 | * <tt>"rw"</tt> but the given string does not denote an | ||
| 102 | * existing, writable regular file and a new regular file of | ||
| 103 | * that name cannot be created, or if some other error occurs | ||
| 104 | * while opening or creating the file | ||
| 105 | * @exception SecurityException if a security manager exists and its | ||
| 106 | * <code>checkRead</code> method denies read access to the file | ||
| 107 | * or the mode is "rw" and the security manager's | ||
| 108 | * <code>checkWrite</code> method denies write access to the file | ||
| 109 | * @see java.lang.SecurityException | ||
| 110 | * @see java.lang.SecurityManager#checkRead(java.lang.String) | ||
| 111 | * @see java.lang.SecurityManager#checkWrite(java.lang.String) | ||
| 112 | * @revised 1.4 | ||
| 113 | * @spec JSR-51 | ||
| 114 | */ | ||
| 115 | public RandomAccessFile(String name, String mode) | ||
| 116 | throws FileNotFoundException | ||
| 117 | { | ||
| 118 | this(name != null ? new File(name) : null, mode); | ||
| 119 | } | ||
| 120 | |||
| 121 | /** | ||
| 122 | * Creates a random access file stream to read from, and optionally to | ||
| 123 | * write to, the file specified by the {@link File} argument. A new {@link | ||
| 124 | * FileDescriptor} object is created to represent this file connection. | ||
| 125 | * | ||
| 126 | * <a name="mode"><p> The <tt>mode</tt> argument specifies the access mode | ||
| 127 | * in which the file is to be opened. The permitted values and their | ||
| 128 | * meanings are: | ||
| 129 | * | ||
| 130 | * <blockquote><table summary="Access mode permitted values and meanings"> | ||
| 131 | * <tr><th><p align="left">Value</p></th><th><p align="left">Meaning</p></th></tr> | ||
| 132 | * <tr><td valign="top"><tt>"r"</tt></td> | ||
| 133 | * <td> Open for reading only. Invoking any of the <tt>write</tt> | ||
| 134 | * methods of the resulting object will cause an {@link | ||
| 135 | * java.io.IOException} to be thrown. </td></tr> | ||
| 136 | * <tr><td valign="top"><tt>"rw"</tt></td> | ||
| 137 | * <td> Open for reading and writing. If the file does not already | ||
| 138 | * exist then an attempt will be made to create it. </td></tr> | ||
| 139 | * <tr><td valign="top"><tt>"rws"</tt></td> | ||
| 140 | * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also | ||
| 141 | * require that every update to the file's content or metadata be | ||
| 142 | * written synchronously to the underlying storage device. </td></tr> | ||
| 143 | * <tr><td valign="top"><tt>"rwd" </tt></td> | ||
| 144 | * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also | ||
| 145 | * require that every update to the file's content be written | ||
| 146 | * synchronously to the underlying storage device. </td></tr> | ||
| 147 | * </table></blockquote> | ||
| 148 | * | ||
| 149 | * The <tt>"rws"</tt> and <tt>"rwd"</tt> modes work much like the {@link | ||
| 150 | * java.nio.channels.FileChannel#force(boolean) force(boolean)} method of | ||
| 151 | * the {@link java.nio.channels.FileChannel} class, passing arguments of | ||
| 152 | * <tt>true</tt> and <tt>false</tt>, respectively, except that they always | ||
| 153 | * apply to every I/O operation and are therefore often more efficient. If | ||
| 154 | * the file resides on a local storage device then when an invocation of a | ||
| 155 | * method of this class returns it is guaranteed that all changes made to | ||
| 156 | * the file by that invocation will have been written to that device. This | ||
| 157 | * is useful for ensuring that critical information is not lost in the | ||
| 158 | * event of a system crash. If the file does not reside on a local device | ||
| 159 | * then no such guarantee is made. | ||
| 160 | * | ||
| 161 | * <p> The <tt>"rwd"</tt> mode can be used to reduce the number of I/O | ||
| 162 | * operations performed. Using <tt>"rwd"</tt> only requires updates to the | ||
| 163 | * file's content to be written to storage; using <tt>"rws"</tt> requires | ||
| 164 | * updates to both the file's content and its metadata to be written, which | ||
| 165 | * generally requires at least one more low-level I/O operation. | ||
| 166 | * | ||
| 167 | * <p> If there is a security manager, its <code>checkRead</code> method is | ||
| 168 | * called with the pathname of the <code>file</code> argument as its | ||
| 169 | * argument to see if read access to the file is allowed. If the mode | ||
| 170 | * allows writing, the security manager's <code>checkWrite</code> method is | ||
| 171 | * also called with the path argument to see if write access to the file is | ||
| 172 | * allowed. | ||
| 173 | * | ||
| 174 | * @param file the file object | ||
| 175 | * @param mode the access mode, as described | ||
| 176 | * <a href="#mode">above</a> | ||
| 177 | * @exception IllegalArgumentException if the mode argument is not equal | ||
| 178 | * to one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or | ||
| 179 | * <tt>"rwd"</tt> | ||
| 180 | * @exception FileNotFoundException | ||
| 181 | * if the mode is <tt>"r"</tt> but the given file object does | ||
| 182 | * not denote an existing regular file, or if the mode begins | ||
| 183 | * with <tt>"rw"</tt> but the given file object does not denote | ||
| 184 | * an existing, writable regular file and a new regular file of | ||
| 185 | * that name cannot be created, or if some other error occurs | ||
| 186 | * while opening or creating the file | ||
| 187 | * @exception SecurityException if a security manager exists and its | ||
| 188 | * <code>checkRead</code> method denies read access to the file | ||
| 189 | * or the mode is "rw" and the security manager's | ||
| 190 | * <code>checkWrite</code> method denies write access to the file | ||
| 191 | * @see java.lang.SecurityManager#checkRead(java.lang.String) | ||
| 192 | * @see java.lang.SecurityManager#checkWrite(java.lang.String) | ||
| 193 | * @see java.nio.channels.FileChannel#force(boolean) | ||
| 194 | * @revised 1.4 | ||
| 195 | * @spec JSR-51 | ||
| 196 | */ | ||
| 197 | public RandomAccessFile(File file, String mode) | ||
| 198 | throws FileNotFoundException | ||
| 199 | { | ||
| 200 | String name = (file != null ? file.getPath() : null); | ||
| 201 | int imode = -1; | ||
| 202 | if (mode.equals("r")) | ||
| 203 | imode = O_RDONLY; | ||
| 204 | else if (mode.startsWith("rw")) { | ||
| 205 | imode = O_RDWR; | ||
| 206 | rw = true; | ||
| 207 | if (mode.length() > 2) { | ||
| 208 | if (mode.equals("rws")) | ||
| 209 | imode |= O_SYNC; | ||
| 210 | else if (mode.equals("rwd")) | ||
| 211 | imode |= O_DSYNC; | ||
| 212 | else | ||
| 213 | imode = -1; | ||
| 214 | } | ||
| 215 | } | ||
| 216 | if (imode < 0) | ||
| 217 | throw new IllegalArgumentException("Illegal mode \"" + mode | ||
| 218 | + "\" must be one of " | ||
| 219 | + "\"r\", \"rw\", \"rws\"," | ||
| 220 | + " or \"rwd\""); | ||
| 221 | SecurityManager security = System.getSecurityManager(); | ||
| 222 | if (security != null) { | ||
| 223 | security.checkRead(name); | ||
| 224 | if (rw) { | ||
| 225 | security.checkWrite(name); | ||
| 226 | } | ||
| 227 | } | ||
| 228 | if (name == null) { | ||
| 229 | throw new NullPointerException(); | ||
| 230 | } | ||
| 231 | fd = new FileDescriptor(); | ||
| 232 | fd.incrementAndGetUseCount(); | ||
| 233 | open(name, imode); | ||
| 234 | } | ||
| 235 | |||
| 236 | /** | ||
| 237 | * Returns the opaque file descriptor object associated with this | ||
| 238 | * stream. </p> | ||
| 239 | * | ||
| 240 | * @return the file descriptor object associated with this stream. | ||
| 241 | * @exception IOException if an I/O error occurs. | ||
| 242 | * @see java.io.FileDescriptor | ||
| 243 | */ | ||
| 244 | public final FileDescriptor getFD() throws IOException { | ||
| 245 | if (fd != null) return fd; | ||
| 246 | throw new IOException(); | ||
| 247 | } | ||
| 248 | |||
| 249 | /** | ||
| 250 | * Returns the unique {@link java.nio.channels.FileChannel FileChannel} | ||
| 251 | * object associated with this file. | ||
| 252 | * | ||
| 253 | * <p> The {@link java.nio.channels.FileChannel#position() | ||
| 254 | * </code>position<code>} of the returned channel will always be equal to | ||
| 255 | * this object's file-pointer offset as returned by the {@link | ||
| 256 | * #getFilePointer getFilePointer} method. Changing this object's | ||
| 257 | * file-pointer offset, whether explicitly or by reading or writing bytes, | ||
| 258 | * will change the position of the channel, and vice versa. Changing the | ||
| 259 | * file's length via this object will change the length seen via the file | ||
| 260 | * channel, and vice versa. | ||
| 261 | * | ||
| 262 | * @return the file channel associated with this file | ||
| 263 | * | ||
| 264 | * @since 1.4 | ||
| 265 | * @spec JSR-51 | ||
| 266 | */ | ||
| 267 | public final FileChannel getChannel() { | ||
| 268 | synchronized (this) { | ||
| 269 | if (channel == null) { | ||
| 270 | channel = FileChannelImpl.open(fd, true, rw, this); | ||
| 271 | |||
| 272 | /* | ||
| 273 | * FileDescriptor could be shared by FileInputStream or | ||
| 274 | * FileOutputStream. | ||
| 275 | * Ensure that FD is GC'ed only when all the streams/channels | ||
| 276 | * are done using it. | ||
| 277 | * Increment fd's use count. Invoking the channel's close() | ||
| 278 | * method will result in decrementing the use count set for | ||
| 279 | * the channel. | ||
| 280 | */ | ||
| 281 | fd.incrementAndGetUseCount(); | ||
| 282 | } | ||
| 283 | return channel; | ||
| 284 | } | ||
| 285 | } | ||
| 286 | |||
| 287 | /** | ||
| 288 | * Opens a file and returns the file descriptor. The file is | ||
| 289 | * opened in read-write mode if the O_RDWR bit in <code>mode</code> | ||
| 290 | * is true, else the file is opened as read-only. | ||
| 291 | * If the <code>name</code> refers to a directory, an IOException | ||
| 292 | * is thrown. | ||
| 293 | * | ||
| 294 | * @param name the name of the file | ||
| 295 | * @param mode the mode flags, a combination of the O_ constants | ||
| 296 | * defined above | ||
| 297 | */ | ||
| 298 | private native void open(String name, int mode) | ||
| 299 | throws FileNotFoundException; | ||
| 300 | |||
| 301 | // 'Read' primitives | ||
| 302 | |||
| 303 | /** | ||
| 304 | * Reads a byte of data from this file. The byte is returned as an | ||
| 305 | * integer in the range 0 to 255 (<code>0x00-0x0ff</code>). This | ||
| 306 | * method blocks if no input is yet available. | ||
| 307 | * <p> | ||
| 308 | * Although <code>RandomAccessFile</code> is not a subclass of | ||
| 309 | * <code>InputStream</code>, this method behaves in exactly the same | ||
| 310 | * way as the {@link InputStream#read()} method of | ||
| 311 | * <code>InputStream</code>. | ||
| 312 | * | ||
| 313 | * @return the next byte of data, or <code>-1</code> if the end of the | ||
| 314 | * file has been reached. | ||
| 315 | * @exception IOException if an I/O error occurs. Not thrown if | ||
| 316 | * end-of-file has been reached. | ||
| 317 | */ | ||
| 318 | public native int read() throws IOException; | ||
| 319 | |||
| 320 | /** | ||
| 321 | * Reads a sub array as a sequence of bytes. | ||
| 322 | * @param b the buffer into which the data is read. | ||
| 323 | * @param off the start offset of the data. | ||
| 324 | * @param len the number of bytes to read. | ||
| 325 | * @exception IOException If an I/O error has occurred. | ||
| 326 | */ | ||
| 327 | private native int readBytes(byte b[], int off, int len) throws IOException; | ||
| 328 | |||
| 329 | /** | ||
| 330 | * Reads up to <code>len</code> bytes of data from this file into an | ||
| 331 | * array of bytes. This method blocks until at least one byte of input | ||
| 332 | * is available. | ||
| 333 | * <p> | ||
| 334 | * Although <code>RandomAccessFile</code> is not a subclass of | ||
| 335 | * <code>InputStream</code>, this method behaves in exactly the | ||
| 336 | * same way as the {@link InputStream#read(byte[], int, int)} method of | ||
| 337 | * <code>InputStream</code>. | ||
| 338 | * | ||
| 339 | * @param b the buffer into which the data is read. | ||
| 340 | * @param off the start offset in array <code>b</code> | ||
| 341 | * at which the data is written. | ||
| 342 | * @param len the maximum number of bytes read. | ||
| 343 | * @return the total number of bytes read into the buffer, or | ||
| 344 | * <code>-1</code> if there is no more data because the end of | ||
| 345 | * the file has been reached. | ||
| 346 | * @exception IOException If the first byte cannot be read for any reason | ||
| 347 | * other than end of file, or if the random access file has been closed, or if | ||
| 348 | * some other I/O error occurs. | ||
| 349 | * @exception NullPointerException If <code>b</code> is <code>null</code>. | ||
| 350 | * @exception IndexOutOfBoundsException If <code>off</code> is negative, | ||
| 351 | * <code>len</code> is negative, or <code>len</code> is greater than | ||
| 352 | * <code>b.length - off</code> | ||
| 353 | */ | ||
| 354 | public int read(byte b[], int off, int len) throws IOException { | ||
| 355 | return readBytes(b, off, len); | ||
| 356 | } | ||
| 357 | |||
| 358 | /** | ||
| 359 | * Reads up to <code>b.length</code> bytes of data from this file | ||
| 360 | * into an array of bytes. This method blocks until at least one byte | ||
| 361 | * of input is available. | ||
| 362 | * <p> | ||
| 363 | * Although <code>RandomAccessFile</code> is not a subclass of | ||
| 364 | * <code>InputStream</code>, this method behaves in exactly the | ||
| 365 | * same way as the {@link InputStream#read(byte[])} method of | ||
| 366 | * <code>InputStream</code>. | ||
| 367 | * | ||
| 368 | * @param b the buffer into which the data is read. | ||
| 369 | * @return the total number of bytes read into the buffer, or | ||
| 370 | * <code>-1</code> if there is no more data because the end of | ||
| 371 | * this file has been reached. | ||
| 372 | * @exception IOException If the first byte cannot be read for any reason | ||
| 373 | * other than end of file, or if the random access file has been closed, or if | ||
| 374 | * some other I/O error occurs. | ||
| 375 | * @exception NullPointerException If <code>b</code> is <code>null</code>. | ||
| 376 | */ | ||
| 377 | public int read(byte b[]) throws IOException { | ||
| 378 | return readBytes(b, 0, b.length); | ||
| 379 | } | ||
| 380 | |||
| 381 | /** | ||
| 382 | * Reads <code>b.length</code> bytes from this file into the byte | ||
| 383 | * array, starting at the current file pointer. This method reads | ||
| 384 | * repeatedly from the file until the requested number of bytes are | ||
| 385 | * read. This method blocks until the requested number of bytes are | ||
| 386 | * read, the end of the stream is detected, or an exception is thrown. | ||
| 387 | * | ||
| 388 | * @param b the buffer into which the data is read. | ||
| 389 | * @exception EOFException if this file reaches the end before reading | ||
| 390 | * all the bytes. | ||
| 391 | * @exception IOException if an I/O error occurs. | ||
| 392 | */ | ||
| 393 | public final void readFully(byte b[]) throws IOException { | ||
| 394 | readFully(b, 0, b.length); | ||
| 395 | } | ||
| 396 | |||
| 397 | /** | ||
| 398 | * Reads exactly <code>len</code> bytes from this file into the byte | ||
| 399 | * array, starting at the current file pointer. This method reads | ||
| 400 | * repeatedly from the file until the requested number of bytes are | ||
| 401 | * read. This method blocks until the requested number of bytes are | ||
| 402 | * read, the end of the stream is detected, or an exception is thrown. | ||
| 403 | * | ||
| 404 | * @param b the buffer into which the data is read. | ||
| 405 | * @param off the start offset of the data. | ||
| 406 | * @param len the number of bytes to read. | ||
| 407 | * @exception EOFException if this file reaches the end before reading | ||
| 408 | * all the bytes. | ||
| 409 | * @exception IOException if an I/O error occurs. | ||
| 410 | */ | ||
| 411 | public final void readFully(byte b[], int off, int len) throws IOException { | ||
| 412 | int n = 0; | ||
| 413 | do { | ||
| 414 | int count = this.read(b, off + n, len - n); | ||
| 415 | if (count < 0) | ||
| 416 | throw new EOFException(); | ||
| 417 | n += count; | ||
| 418 | } while (n < len); | ||
| 419 | } | ||
| 420 | |||
| 421 | /** | ||
| 422 | * Attempts to skip over <code>n</code> bytes of input discarding the | ||
| 423 | * skipped bytes. | ||
| 424 | * <p> | ||
| 425 | * | ||
| 426 | * This method may skip over some smaller number of bytes, possibly zero. | ||
| 427 | * This may result from any of a number of conditions; reaching end of | ||
| 428 | * file before <code>n</code> bytes have been skipped is only one | ||
| 429 | * possibility. This method never throws an <code>EOFException</code>. | ||
| 430 | * The actual number of bytes skipped is returned. If <code>n</code> | ||
| 431 | * is negative, no bytes are skipped. | ||
| 432 | * | ||
| 433 | * @param n the number of bytes to be skipped. | ||
| 434 | * @return the actual number of bytes skipped. | ||
| 435 | * @exception IOException if an I/O error occurs. | ||
| 436 | */ | ||
| 437 | public int skipBytes(int n) throws IOException { | ||
| 438 | long pos; | ||
| 439 | long len; | ||
| 440 | long newpos; | ||
| 441 | |||
| 442 | if (n <= 0) { | ||
| 443 | return 0; | ||
| 444 | } | ||
| 445 | pos = getFilePointer(); | ||
| 446 | len = length(); | ||
| 447 | newpos = pos + n; | ||
| 448 | if (newpos > len) { | ||
| 449 | newpos = len; | ||
| 450 | } | ||
| 451 | seek(newpos); | ||
| 452 | |||
| 453 | /* return the actual number of bytes skipped */ | ||
| 454 | return (int) (newpos - pos); | ||
| 455 | } | ||
| 456 | |||
| 457 | // 'Write' primitives | ||
| 458 | |||
| 459 | /** | ||
| 460 | * Writes the specified byte to this file. The write starts at | ||
| 461 | * the current file pointer. | ||
| 462 | * | ||
| 463 | * @param b the <code>byte</code> to be written. | ||
| 464 | * @exception IOException if an I/O error occurs. | ||
| 465 | */ | ||
| 466 | public native void write(int b) throws IOException; | ||
| 467 | |||
| 468 | /** | ||
| 469 | * Writes a sub array as a sequence of bytes. | ||
| 470 | * @param b the data to be written | ||
| 471 | |||
| 472 | * @param off the start offset in the data | ||
| 473 | * @param len the number of bytes that are written | ||
| 474 | * @exception IOException If an I/O error has occurred. | ||
| 475 | */ | ||
| 476 | private native void writeBytes(byte b[], int off, int len) throws IOException; | ||
| 477 | |||
| 478 | /** | ||
| 479 | * Writes <code>b.length</code> bytes from the specified byte array | ||
| 480 | * to this file, starting at the current file pointer. | ||
| 481 | * | ||
| 482 | * @param b the data. | ||
| 483 | * @exception IOException if an I/O error occurs. | ||
| 484 | */ | ||
| 485 | public void write(byte b[]) throws IOException { | ||
| 486 | writeBytes(b, 0, b.length); | ||
| 487 | } | ||
| 488 | |||
| 489 | /** | ||
| 490 | * Writes <code>len</code> bytes from the specified byte array | ||
| 491 | * starting at offset <code>off</code> to this file. | ||
| 492 | * | ||
| 493 | * @param b the data. | ||
| 494 | * @param off the start offset in the data. | ||
| 495 | * @param len the number of bytes to write. | ||
| 496 | * @exception IOException if an I/O error occurs. | ||
| 497 | */ | ||
| 498 | public void write(byte b[], int off, int len) throws IOException { | ||
| 499 | writeBytes(b, off, len); | ||
| 500 | } | ||
| 501 | |||
| 502 | // 'Random access' stuff | ||
| 503 | |||
| 504 | /** | ||
| 505 | * Returns the current offset in this file. | ||
| 506 | * | ||
| 507 | * @return the offset from the beginning of the file, in bytes, | ||
| 508 | * at which the next read or write occurs. | ||
| 509 | * @exception IOException if an I/O error occurs. | ||
| 510 | */ | ||
| 511 | public native long getFilePointer() throws IOException; | ||
| 512 | |||
| 513 | /** | ||
| 514 | * Sets the file-pointer offset, measured from the beginning of this | ||
| 515 | * file, at which the next read or write occurs. The offset may be | ||
| 516 | * set beyond the end of the file. Setting the offset beyond the end | ||
| 517 | * of the file does not change the file length. The file length will | ||
| 518 | * change only by writing after the offset has been set beyond the end | ||
| 519 | * of the file. | ||
| 520 | * | ||
| 521 | * @param pos the offset position, measured in bytes from the | ||
| 522 | * beginning of the file, at which to set the file | ||
| 523 | * pointer. | ||
| 524 | * @exception IOException if <code>pos</code> is less than | ||
| 525 | * <code>0</code> or if an I/O error occurs. | ||
| 526 | */ | ||
| 527 | public native void seek(long pos) throws IOException; | ||
| 528 | |||
| 529 | /** | ||
| 530 | * Returns the length of this file. | ||
| 531 | * | ||
| 532 | * @return the length of this file, measured in bytes. | ||
| 533 | * @exception IOException if an I/O error occurs. | ||
| 534 | */ | ||
| 535 | public native long length() throws IOException; | ||
| 536 | |||
| 537 | /** | ||
| 538 | * Sets the length of this file. | ||
| 539 | * | ||
| 540 | * <p> If the present length of the file as returned by the | ||
| 541 | * <code>length</code> method is greater than the <code>newLength</code> | ||
| 542 | * argument then the file will be truncated. In this case, if the file | ||
| 543 | * offset as returned by the <code>getFilePointer</code> method is greater | ||
| 544 | * than <code>newLength</code> then after this method returns the offset | ||
| 545 | * will be equal to <code>newLength</code>. | ||
| 546 | * | ||
| 547 | * <p> If the present length of the file as returned by the | ||
| 548 | * <code>length</code> method is smaller than the <code>newLength</code> | ||
| 549 | * argument then the file will be extended. In this case, the contents of | ||
| 550 | * the extended portion of the file are not defined. | ||
| 551 | * | ||
| 552 | * @param newLength The desired length of the file | ||
| 553 | * @exception IOException If an I/O error occurs | ||
| 554 | * @since 1.2 | ||
| 555 | */ | ||
| 556 | public native void setLength(long newLength) throws IOException; | ||
| 557 | |||
| 558 | /** | ||
| 559 | * Closes this random access file stream and releases any system | ||
| 560 | * resources associated with the stream. A closed random access | ||
| 561 | * file cannot perform input or output operations and cannot be | ||
| 562 | * reopened. | ||
| 563 | * | ||
| 564 | * <p> If this file has an associated channel then the channel is closed | ||
| 565 | * as well. | ||
| 566 | * | ||
| 567 | * @exception IOException if an I/O error occurs. | ||
| 568 | * | ||
| 569 | * @revised 1.4 | ||
| 570 | * @spec JSR-51 | ||
| 571 | */ | ||
| 572 | public void close() throws IOException { | ||
| 573 | synchronized (closeLock) { | ||
| 574 | if (closed) { | ||
| 575 | return; | ||
| 576 | } | ||
| 577 | closed = true; | ||
| 578 | } | ||
| 579 | if (channel != null) { | ||
| 580 | /* | ||
| 581 | * Decrement FD use count associated with the channel. The FD use | ||
| 582 | * count is incremented whenever a new channel is obtained from | ||
| 583 | * this stream. | ||
| 584 | */ | ||
| 585 | fd.decrementAndGetUseCount(); | ||
| 586 | channel.close(); | ||
| 587 | } | ||
| 588 | |||
| 589 | /* | ||
| 590 | * Decrement FD use count associated with this stream. | ||
| 591 | * The count got incremented by FileDescriptor during its construction. | ||
| 592 | */ | ||
| 593 | fd.decrementAndGetUseCount(); | ||
| 594 | close0(); | ||
| 595 | } | ||
| 596 | |||
| 597 | // | ||
| 598 | // Some "reading/writing Java data types" methods stolen from | ||
| 599 | // DataInputStream and DataOutputStream. | ||
| 600 | // | ||
| 601 | |||
| 602 | /** | ||
| 603 | * Reads a <code>boolean</code> from this file. This method reads a | ||
| 604 | * single byte from the file, starting at the current file pointer. | ||
| 605 | * A value of <code>0</code> represents | ||
| 606 | * <code>false</code>. Any other value represents <code>true</code>. | ||
| 607 | * This method blocks until the byte is read, the end of the stream | ||
| 608 | * is detected, or an exception is thrown. | ||
| 609 | * | ||
| 610 | * @return the <code>boolean</code> value read. | ||
| 611 | * @exception EOFException if this file has reached the end. | ||
| 612 | * @exception IOException if an I/O error occurs. | ||
| 613 | */ | ||
| 614 | public final boolean readBoolean() throws IOException { | ||
| 615 | int ch = this.read(); | ||
| 616 | if (ch < 0) | ||
| 617 | throw new EOFException(); | ||
| 618 | return (ch != 0); | ||
| 619 | } | ||
| 620 | |||
| 621 | /** | ||
| 622 | * Reads a signed eight-bit value from this file. This method reads a | ||
| 623 | * byte from the file, starting from the current file pointer. | ||
| 624 | * If the byte read is <code>b</code>, where | ||
| 625 | * <code>0 <= b <= 255</code>, | ||
| 626 | * then the result is: | ||
| 627 | * <blockquote><pre> | ||
| 628 | * (byte)(b) | ||
| 629 | * </pre></blockquote> | ||
| 630 | * <p> | ||
| 631 | * This method blocks until the byte is read, the end of the stream | ||
| 632 | * is detected, or an exception is thrown. | ||
| 633 | * | ||
| 634 | * @return the next byte of this file as a signed eight-bit | ||
| 635 | * <code>byte</code>. | ||
| 636 | * @exception EOFException if this file has reached the end. | ||
| 637 | * @exception IOException if an I/O error occurs. | ||
| 638 | */ | ||
| 639 | public final byte readByte() throws IOException { | ||
| 640 | int ch = this.read(); | ||
| 641 | if (ch < 0) | ||
| 642 | throw new EOFException(); | ||
| 643 | return (byte)(ch); | ||
| 644 | } | ||
| 645 | |||
| 646 | /** | ||
| 647 | * Reads an unsigned eight-bit number from this file. This method reads | ||
| 648 | * a byte from this file, starting at the current file pointer, | ||
| 649 | * and returns that byte. | ||
| 650 | * <p> | ||
| 651 | * This method blocks until the byte is read, the end of the stream | ||
| 652 | * is detected, or an exception is thrown. | ||
| 653 | * | ||
| 654 | * @return the next byte of this file, interpreted as an unsigned | ||
| 655 | * eight-bit number. | ||
| 656 | * @exception EOFException if this file has reached the end. | ||
| 657 | * @exception IOException if an I/O error occurs. | ||
| 658 | */ | ||
| 659 | public final int readUnsignedByte() throws IOException { | ||
| 660 | int ch = this.read(); | ||
| 661 | if (ch < 0) | ||
| 662 | throw new EOFException(); | ||
| 663 | return ch; | ||
| 664 | } | ||
| 665 | |||
| 666 | /** | ||
| 667 | * Reads a signed 16-bit number from this file. The method reads two | ||
| 668 | * bytes from this file, starting at the current file pointer. | ||
| 669 | * If the two bytes read, in order, are | ||
| 670 | * <code>b1</code> and <code>b2</code>, where each of the two values is | ||
| 671 | * between <code>0</code> and <code>255</code>, inclusive, then the | ||
| 672 | * result is equal to: | ||
| 673 | * <blockquote><pre> | ||
| 674 | * (short)((b1 << 8) | b2) | ||
| 675 | * </pre></blockquote> | ||
| 676 | * <p> | ||
| 677 | * This method blocks until the two bytes are read, the end of the | ||
| 678 | * stream is detected, or an exception is thrown. | ||
| 679 | * | ||
| 680 | * @return the next two bytes of this file, interpreted as a signed | ||
| 681 | * 16-bit number. | ||
| 682 | * @exception EOFException if this file reaches the end before reading | ||
| 683 | * two bytes. | ||
| 684 | * @exception IOException if an I/O error occurs. | ||
| 685 | */ | ||
| 686 | public final short readShort() throws IOException { | ||
| 687 | int ch1 = this.read(); | ||
| 688 | int ch2 = this.read(); | ||
| 689 | if ((ch1 | ch2) < 0) | ||
| 690 | throw new EOFException(); | ||
| 691 | return (short)((ch1 << 8) + (ch2 << 0)); | ||
| 692 | } | ||
| 693 | |||
| 694 | /** | ||
| 695 | * Reads an unsigned 16-bit number from this file. This method reads | ||
| 696 | * two bytes from the file, starting at the current file pointer. | ||
| 697 | * If the bytes read, in order, are | ||
| 698 | * <code>b1</code> and <code>b2</code>, where | ||
| 699 | * <code>0 <= b1, b2 <= 255</code>, | ||
| 700 | * then the result is equal to: | ||
| 701 | * <blockquote><pre> | ||
| 702 | * (b1 << 8) | b2 | ||
| 703 | * </pre></blockquote> | ||
| 704 | * <p> | ||
| 705 | * This method blocks until the two bytes are read, the end of the | ||
| 706 | * stream is detected, or an exception is thrown. | ||
| 707 | * | ||
| 708 | * @return the next two bytes of this file, interpreted as an unsigned | ||
| 709 | * 16-bit integer. | ||
| 710 | * @exception EOFException if this file reaches the end before reading | ||
| 711 | * two bytes. | ||
| 712 | * @exception IOException if an I/O error occurs. | ||
| 713 | */ | ||
| 714 | public final int readUnsignedShort() throws IOException { | ||
| 715 | int ch1 = this.read(); | ||
| 716 | int ch2 = this.read(); | ||
| 717 | if ((ch1 | ch2) < 0) | ||
| 718 | throw new EOFException(); | ||
| 719 | return (ch1 << 8) + (ch2 << 0); | ||
| 720 | } | ||
| 721 | |||
| 722 | /** | ||
| 723 | * Reads a character from this file. This method reads two | ||
| 724 | * bytes from the file, starting at the current file pointer. | ||
| 725 | * If the bytes read, in order, are | ||
| 726 | * <code>b1</code> and <code>b2</code>, where | ||
| 727 | * <code>0 <= b1, b2 <= 255</code>, | ||
| 728 | * then the result is equal to: | ||
| 729 | * <blockquote><pre> | ||
| 730 | * (char)((b1 << 8) | b2) | ||
| 731 | * </pre></blockquote> | ||
| 732 | * <p> | ||
| 733 | * This method blocks until the two bytes are read, the end of the | ||
| 734 | * stream is detected, or an exception is thrown. | ||
| 735 | * | ||
| 736 | * @return the next two bytes of this file, interpreted as a | ||
| 737 | * <code>char</code>. | ||
| 738 | * @exception EOFException if this file reaches the end before reading | ||
| 739 | * two bytes. | ||
| 740 | * @exception IOException if an I/O error occurs. | ||
| 741 | */ | ||
| 742 | public final char readChar() throws IOException { | ||
| 743 | int ch1 = this.read(); | ||
| 744 | int ch2 = this.read(); | ||
| 745 | if ((ch1 | ch2) < 0) | ||
| 746 | throw new EOFException(); | ||
| 747 | return (char)((ch1 << 8) + (ch2 << 0)); | ||
| 748 | } | ||
| 749 | |||
| 750 | /** | ||
| 751 | * Reads a signed 32-bit integer from this file. This method reads 4 | ||
| 752 | * bytes from the file, starting at the current file pointer. | ||
| 753 | * If the bytes read, in order, are <code>b1</code>, | ||
| 754 | * <code>b2</code>, <code>b3</code>, and <code>b4</code>, where | ||
| 755 | * <code>0 <= b1, b2, b3, b4 <= 255</code>, | ||
| 756 | * then the result is equal to: | ||
| 757 | * <blockquote><pre> | ||
| 758 | * (b1 << 24) | (b2 << 16) + (b3 << 8) + b4 | ||
| 759 | * </pre></blockquote> | ||
| 760 | * <p> | ||
| 761 | * This method blocks until the four bytes are read, the end of the | ||
| 762 | * stream is detected, or an exception is thrown. | ||
| 763 | * | ||
| 764 | * @return the next four bytes of this file, interpreted as an | ||
| 765 | * <code>int</code>. | ||
| 766 | * @exception EOFException if this file reaches the end before reading | ||
| 767 | * four bytes. | ||
| 768 | * @exception IOException if an I/O error occurs. | ||
| 769 | */ | ||
| 770 | public final int readInt() throws IOException { | ||
| 771 | int ch1 = this.read(); | ||
| 772 | int ch2 = this.read(); | ||
| 773 | int ch3 = this.read(); | ||
| 774 | int ch4 = this.read(); | ||
| 775 | if ((ch1 | ch2 | ch3 | ch4) < 0) | ||
| 776 | throw new EOFException(); | ||
| 777 | return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0)); | ||
| 778 | } | ||
| 779 | |||
| 780 | /** | ||
| 781 | * Reads a signed 64-bit integer from this file. This method reads eight | ||
| 782 | * bytes from the file, starting at the current file pointer. | ||
| 783 | * If the bytes read, in order, are | ||
| 784 | * <code>b1</code>, <code>b2</code>, <code>b3</code>, | ||
| 785 | * <code>b4</code>, <code>b5</code>, <code>b6</code>, | ||
| 786 | * <code>b7</code>, and <code>b8,</code> where: | ||
| 787 | * <blockquote><pre> | ||
| 788 | * 0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255, | ||
| 789 | * </pre></blockquote> | ||
| 790 | * <p> | ||
| 791 | * then the result is equal to: | ||
| 792 | * <p><blockquote><pre> | ||
| 793 | * ((long)b1 << 56) + ((long)b2 << 48) | ||
| 794 | * + ((long)b3 << 40) + ((long)b4 << 32) | ||
| 795 | * + ((long)b5 << 24) + ((long)b6 << 16) | ||
| 796 | * + ((long)b7 << 8) + b8 | ||
| 797 | * </pre></blockquote> | ||
| 798 | * <p> | ||
| 799 | * This method blocks until the eight bytes are read, the end of the | ||
| 800 | * stream is detected, or an exception is thrown. | ||
| 801 | * | ||
| 802 | * @return the next eight bytes of this file, interpreted as a | ||
| 803 | * <code>long</code>. | ||
| 804 | * @exception EOFException if this file reaches the end before reading | ||
| 805 | * eight bytes. | ||
| 806 | * @exception IOException if an I/O error occurs. | ||
| 807 | */ | ||
| 808 | public final long readLong() throws IOException { | ||
| 809 | return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL); | ||
| 810 | } | ||
| 811 | |||
| 812 | /** | ||
| 813 | * Reads a <code>float</code> from this file. This method reads an | ||
| 814 | * <code>int</code> value, starting at the current file pointer, | ||
| 815 | * as if by the <code>readInt</code> method | ||
| 816 | * and then converts that <code>int</code> to a <code>float</code> | ||
| 817 | * using the <code>intBitsToFloat</code> method in class | ||
| 818 | * <code>Float</code>. | ||
| 819 | * <p> | ||
| 820 | * This method blocks until the four bytes are read, the end of the | ||
| 821 | * stream is detected, or an exception is thrown. | ||
| 822 | * | ||
| 823 | * @return the next four bytes of this file, interpreted as a | ||
| 824 | * <code>float</code>. | ||
| 825 | * @exception EOFException if this file reaches the end before reading | ||
| 826 | * four bytes. | ||
| 827 | * @exception IOException if an I/O error occurs. | ||
| 828 | * @see java.io.RandomAccessFile#readInt() | ||
| 829 | * @see java.lang.Float#intBitsToFloat(int) | ||
| 830 | */ | ||
| 831 | public final float readFloat() throws IOException { | ||
| 832 | return Float.intBitsToFloat(readInt()); | ||
| 833 | } | ||
| 834 | |||
| 835 | /** | ||
| 836 | * Reads a <code>double</code> from this file. This method reads a | ||
| 837 | * <code>long</code> value, starting at the current file pointer, | ||
| 838 | * as if by the <code>readLong</code> method | ||
| 839 | * and then converts that <code>long</code> to a <code>double</code> | ||
| 840 | * using the <code>longBitsToDouble</code> method in | ||
| 841 | * class <code>Double</code>. | ||
| 842 | * <p> | ||
| 843 | * This method blocks until the eight bytes are read, the end of the | ||
| 844 | * stream is detected, or an exception is thrown. | ||
| 845 | * | ||
| 846 | * @return the next eight bytes of this file, interpreted as a | ||
| 847 | * <code>double</code>. | ||
| 848 | * @exception EOFException if this file reaches the end before reading | ||
| 849 | * eight bytes. | ||
| 850 | * @exception IOException if an I/O error occurs. | ||
| 851 | * @see java.io.RandomAccessFile#readLong() | ||
| 852 | * @see java.lang.Double#longBitsToDouble(long) | ||
| 853 | */ | ||
| 854 | public final double readDouble() throws IOException { | ||
| 855 | return Double.longBitsToDouble(readLong()); | ||
| 856 | } | ||
| 857 | |||
| 858 | /** | ||
| 859 | * Reads the next line of text from this file. This method successively | ||
| 860 | * reads bytes from the file, starting at the current file pointer, | ||
| 861 | * until it reaches a line terminator or the end | ||
| 862 | * of the file. Each byte is converted into a character by taking the | ||
| 863 | * byte's value for the lower eight bits of the character and setting the | ||
| 864 | * high eight bits of the character to zero. This method does not, | ||
| 865 | * therefore, support the full Unicode character set. | ||
| 866 | * | ||
| 867 | * <p> A line of text is terminated by a carriage-return character | ||
| 868 | * (<code>'\r'</code>), a newline character (<code>'\n'</code>), a | ||
| 869 | * carriage-return character immediately followed by a newline character, | ||
| 870 | * or the end of the file. Line-terminating characters are discarded and | ||
| 871 | * are not included as part of the string returned. | ||
| 872 | * | ||
| 873 | * <p> This method blocks until a newline character is read, a carriage | ||
| 874 | * return and the byte following it are read (to see if it is a newline), | ||
| 875 | * the end of the file is reached, or an exception is thrown. | ||
| 876 | * | ||
| 877 | * @return the next line of text from this file, or null if end | ||
| 878 | * of file is encountered before even one byte is read. | ||
| 879 | * @exception IOException if an I/O error occurs. | ||
| 880 | */ | ||
| 881 | |||
| 882 | public final String readLine() throws IOException { | ||
| 883 | StringBuffer input = new StringBuffer(); | ||
| 884 | int c = -1; | ||
| 885 | boolean eol = false; | ||
| 886 | |||
| 887 | while (!eol) { | ||
| 888 | switch (c = read()) { | ||
| 889 | case -1: | ||
| 890 | case '\n': | ||
| 891 | eol = true; | ||
| 892 | break; | ||
| 893 | case '\r': | ||
| 894 | eol = true; | ||
| 895 | long cur = getFilePointer(); | ||
| 896 | if ((read()) != '\n') { | ||
| 897 | seek(cur); | ||
| 898 | } | ||
| 899 | break; | ||
| 900 | default: | ||
| 901 | input.append((char)c); | ||
| 902 | break; | ||
| 903 | } | ||
| 904 | } | ||
| 905 | |||
| 906 | if ((c == -1) && (input.length() == 0)) { | ||
| 907 | return null; | ||
| 908 | } | ||
| 909 | return input.toString(); | ||
| 910 | } | ||
| 911 | |||
| 912 | /** | ||
| 913 | * Reads in a string from this file. The string has been encoded | ||
| 914 | * using a | ||
| 915 | * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> | ||
| 916 | * format. | ||
| 917 | * <p> | ||
| 918 | * The first two bytes are read, starting from the current file | ||
| 919 | * pointer, as if by | ||
| 920 | * <code>readUnsignedShort</code>. This value gives the number of | ||
| 921 | * following bytes that are in the encoded string, not | ||
| 922 | * the length of the resulting string. The following bytes are then | ||
| 923 | * interpreted as bytes encoding characters in the modified UTF-8 format | ||
| 924 | * and are converted into characters. | ||
| 925 | * <p> | ||
| 926 | * This method blocks until all the bytes are read, the end of the | ||
| 927 | * stream is detected, or an exception is thrown. | ||
| 928 | * | ||
| 929 | * @return a Unicode string. | ||
| 930 | * @exception EOFException if this file reaches the end before | ||
| 931 | * reading all the bytes. | ||
| 932 | * @exception IOException if an I/O error occurs. | ||
| 933 | * @exception UTFDataFormatException if the bytes do not represent | ||
| 934 | * valid modified UTF-8 encoding of a Unicode string. | ||
| 935 | * @see java.io.RandomAccessFile#readUnsignedShort() | ||
| 936 | */ | ||
| 937 | public final String readUTF() throws IOException { | ||
| 938 | return DataInputStream.readUTF(this); | ||
| 939 | } | ||
| 940 | |||
| 941 | /** | ||
| 942 | * Writes a <code>boolean</code> to the file as a one-byte value. The | ||
| 943 | * value <code>true</code> is written out as the value | ||
| 944 | * <code>(byte)1</code>; the value <code>false</code> is written out | ||
| 945 | * as the value <code>(byte)0</code>. The write starts at | ||
| 946 | * the current position of the file pointer. | ||
| 947 | * | ||
| 948 | * @param v a <code>boolean</code> value to be written. | ||
| 949 | * @exception IOException if an I/O error occurs. | ||
| 950 | */ | ||
| 951 | public final void writeBoolean(boolean v) throws IOException { | ||
| 952 | write(v ? 1 : 0); | ||
| 953 | //written++; | ||
| 954 | } | ||
| 955 | |||
| 956 | /** | ||
| 957 | * Writes a <code>byte</code> to the file as a one-byte value. The | ||
| 958 | * write starts at the current position of the file pointer. | ||
| 959 | * | ||
| 960 | * @param v a <code>byte</code> value to be written. | ||
| 961 | * @exception IOException if an I/O error occurs. | ||
| 962 | */ | ||
| 963 | public final void writeByte(int v) throws IOException { | ||
| 964 | write(v); | ||
| 965 | //written++; | ||
| 966 | } | ||
| 967 | |||
| 968 | /** | ||
| 969 | * Writes a <code>short</code> to the file as two bytes, high byte first. | ||
| 970 | * The write starts at the current position of the file pointer. | ||
| 971 | * | ||
| 972 | * @param v a <code>short</code> to be written. | ||
| 973 | * @exception IOException if an I/O error occurs. | ||
| 974 | */ | ||
| 975 | public final void writeShort(int v) throws IOException { | ||
| 976 | write((v >>> 8) & 0xFF); | ||
| 977 | write((v >>> 0) & 0xFF); | ||
| 978 | //written += 2; | ||
| 979 | } | ||
| 980 | |||
| 981 | /** | ||
| 982 | * Writes a <code>char</code> to the file as a two-byte value, high | ||
| 983 | * byte first. The write starts at the current position of the | ||
| 984 | * file pointer. | ||
| 985 | * | ||
| 986 | * @param v a <code>char</code> value to be written. | ||
| 987 | * @exception IOException if an I/O error occurs. | ||
| 988 | */ | ||
| 989 | public final void writeChar(int v) throws IOException { | ||
| 990 | write((v >>> 8) & 0xFF); | ||
| 991 | write((v >>> 0) & 0xFF); | ||
| 992 | //written += 2; | ||
| 993 | } | ||
| 994 | |||
| 995 | /** | ||
| 996 | * Writes an <code>int</code> to the file as four bytes, high byte first. | ||
| 997 | * The write starts at the current position of the file pointer. | ||
| 998 | * | ||
| 999 | * @param v an <code>int</code> to be written. | ||
| 1000 | * @exception IOException if an I/O error occurs. | ||
| 1001 | */ | ||
| 1002 | public final void writeInt(int v) throws IOException { | ||
| 1003 | write((v >>> 24) & 0xFF); | ||
| 1004 | write((v >>> 16) & 0xFF); | ||
| 1005 | write((v >>> 8) & 0xFF); | ||
| 1006 | write((v >>> 0) & 0xFF); | ||
| 1007 | //written += 4; | ||
| 1008 | } | ||
| 1009 | |||
| 1010 | /** | ||
| 1011 | * Writes a <code>long</code> to the file as eight bytes, high byte first. | ||
| 1012 | * The write starts at the current position of the file pointer. | ||
| 1013 | * | ||
| 1014 | * @param v a <code>long</code> to be written. | ||
| 1015 | * @exception IOException if an I/O error occurs. | ||
| 1016 | */ | ||
| 1017 | public final void writeLong(long v) throws IOException { | ||
| 1018 | write((int)(v >>> 56) & 0xFF); | ||
| 1019 | write((int)(v >>> 48) & 0xFF); | ||
| 1020 | write((int)(v >>> 40) & 0xFF); | ||
| 1021 | write((int)(v >>> 32) & 0xFF); | ||
| 1022 | write((int)(v >>> 24) & 0xFF); | ||
| 1023 | write((int)(v >>> 16) & 0xFF); | ||
| 1024 | write((int)(v >>> 8) & 0xFF); | ||
| 1025 | write((int)(v >>> 0) & 0xFF); | ||
| 1026 | //written += 8; | ||
| 1027 | } | ||
| 1028 | |||
| 1029 | /** | ||
| 1030 | * Converts the float argument to an <code>int</code> using the | ||
| 1031 | * <code>floatToIntBits</code> method in class <code>Float</code>, | ||
| 1032 | * and then writes that <code>int</code> value to the file as a | ||
| 1033 | * four-byte quantity, high byte first. The write starts at the | ||
| 1034 | * current position of the file pointer. | ||
| 1035 | * | ||
| 1036 | * @param v a <code>float</code> value to be written. | ||
| 1037 | * @exception IOException if an I/O error occurs. | ||
| 1038 | * @see java.lang.Float#floatToIntBits(float) | ||
| 1039 | */ | ||
| 1040 | public final void writeFloat(float v) throws IOException { | ||
| 1041 | writeInt(Float.floatToIntBits(v)); | ||
| 1042 | } | ||
| 1043 | |||
| 1044 | /** | ||
| 1045 | * Converts the double argument to a <code>long</code> using the | ||
| 1046 | * <code>doubleToLongBits</code> method in class <code>Double</code>, | ||
| 1047 | * and then writes that <code>long</code> value to the file as an | ||
| 1048 | * eight-byte quantity, high byte first. The write starts at the current | ||
| 1049 | * position of the file pointer. | ||
| 1050 | * | ||
| 1051 | * @param v a <code>double</code> value to be written. | ||
| 1052 | * @exception IOException if an I/O error occurs. | ||
| 1053 | * @see java.lang.Double#doubleToLongBits(double) | ||
| 1054 | */ | ||
| 1055 | public final void writeDouble(double v) throws IOException { | ||
| 1056 | writeLong(Double.doubleToLongBits(v)); | ||
| 1057 | } | ||
| 1058 | |||
| 1059 | /** | ||
| 1060 | * Writes the string to the file as a sequence of bytes. Each | ||
| 1061 | * character in the string is written out, in sequence, by discarding | ||
| 1062 | * its high eight bits. The write starts at the current position of | ||
| 1063 | * the file pointer. | ||
| 1064 | * | ||
| 1065 | * @param s a string of bytes to be written. | ||
| 1066 | * @exception IOException if an I/O error occurs. | ||
| 1067 | */ | ||
| 1068 | public final void writeBytes(String s) throws IOException { | ||
| 1069 | int len = s.length(); | ||
| 1070 | byte[] b = new byte[len]; | ||
| 1071 | s.getBytes(0, len, b, 0); | ||
| 1072 | writeBytes(b, 0, len); | ||
| 1073 | } | ||
| 1074 | |||
| 1075 | /** | ||
| 1076 | * Writes a string to the file as a sequence of characters. Each | ||
| 1077 | * character is written to the data output stream as if by the | ||
| 1078 | * <code>writeChar</code> method. The write starts at the current | ||
| 1079 | * position of the file pointer. | ||
| 1080 | * | ||
| 1081 | * @param s a <code>String</code> value to be written. | ||
| 1082 | * @exception IOException if an I/O error occurs. | ||
| 1083 | * @see java.io.RandomAccessFile#writeChar(int) | ||
| 1084 | */ | ||
| 1085 | public final void writeChars(String s) throws IOException { | ||
| 1086 | int clen = s.length(); | ||
| 1087 | int blen = 2*clen; | ||
| 1088 | byte[] b = new byte[blen]; | ||
| 1089 | char[] c = new char[clen]; | ||
| 1090 | s.getChars(0, clen, c, 0); | ||
| 1091 | for (int i = 0, j = 0; i < clen; i++) { | ||
| 1092 | b[j++] = (byte)(c[i] >>> 8); | ||
| 1093 | b[j++] = (byte)(c[i] >>> 0); | ||
| 1094 | } | ||
| 1095 | writeBytes(b, 0, blen); | ||
| 1096 | } | ||
| 1097 | |||
| 1098 | /** | ||
| 1099 | * Writes a string to the file using | ||
| 1100 | * <a href="DataInput.html#modified-utf-8">modified UTF-8</a> | ||
| 1101 | * encoding in a machine-independent manner. | ||
| 1102 | * <p> | ||
| 1103 | * First, two bytes are written to the file, starting at the | ||
| 1104 | * current file pointer, as if by the | ||
| 1105 | * <code>writeShort</code> method giving the number of bytes to | ||
| 1106 | * follow. This value is the number of bytes actually written out, | ||
| 1107 | * not the length of the string. Following the length, each character | ||
| 1108 | * of the string is output, in sequence, using the modified UTF-8 encoding | ||
| 1109 | * for each character. | ||
| 1110 | * | ||
| 1111 | * @param str a string to be written. | ||
| 1112 | * @exception IOException if an I/O error occurs. | ||
| 1113 | */ | ||
| 1114 | public final void writeUTF(String str) throws IOException { | ||
| 1115 | DataOutputStream.writeUTF(str, this); | ||
| 1116 | } | ||
| 1117 | |||
| 1118 | private static native void initIDs(); | ||
| 1119 | |||
| 1120 | private native void close0() throws IOException; | ||
| 1121 | |||
| 1122 | static { | ||
| 1123 | initIDs(); | ||
| 1124 | } | ||
| 1125 | } | ||