- /*
- * @(#)RandomAccessFile.java 1.72 03/01/23
- *
- * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- package java.io;
-
- import java.nio.channels.FileChannel;
- import sun.nio.ch.FileChannelImpl;
-
-
- /**
- * Instances of this class support both reading and writing to a
- * random access file. A random access file behaves like a large
- * array of bytes stored in the file system. There is a kind of cursor,
- * or index into the implied array, called the <em>file pointer</em>
- * input operations read bytes starting at the file pointer and advance
- * the file pointer past the bytes read. If the random access file is
- * created in read/write mode, then output operations are also available;
- * output operations write bytes starting at the file pointer and advance
- * the file pointer past the bytes written. Output operations that write
- * past the current end of the implied array cause the array to be
- * extended. The file pointer can be read by the
- * <code>getFilePointer</code> method and set by the <code>seek</code>
- * method.
- * <p>
- * It is generally true of all the reading routines in this class that
- * if end-of-file is reached before the desired number of bytes has been
- * read, an <code>EOFException</code> (which is a kind of
- * <code>IOException</code>) is thrown. If any byte cannot be read for
- * any reason other than end-of-file, an <code>IOException</code> other
- * than <code>EOFException</code> is thrown. In particular, an
- * <code>IOException</code> may be thrown if the stream has been closed.
- *
- * @author unascribed
- * @version 1.72, 01/23/03
- * @since JDK1.0
- */
-
- public class RandomAccessFile implements DataOutput, DataInput {
-
- private FileDescriptor fd;
- private FileChannel channel = null;
- private boolean rw;
-
- private static final int O_RDONLY = 1;
- private static final int O_RDWR = 2;
- private static final int O_SYNC = 4;
- private static final int O_DSYNC = 8;
-
- /**
- * Creates a random access file stream to read from, and optionally
- * to write to, a file with the specified name. A new
- * {@link FileDescriptor} object is created to represent the
- * connection to the file.
- *
- * <p> The <tt>mode</tt> argument specifies the access mode with which the
- * file is to be opened. The permitted values and their meanings are as
- * specified for the <a
- * href="#mode"><tt>RandomAccessFile(File,String)</tt></a> constructor.
- *
- * <p>
- * If there is a security manager, its <code>checkRead</code> method
- * is called with the <code>name</code> argument
- * as its argument to see if read access to the file is allowed.
- * If the mode allows writing, the security manager's
- * <code>checkWrite</code> method
- * is also called with the <code>name</code> argument
- * as its argument to see if write access to the file is allowed.
- *
- * @param name the system-dependent filename
- * @param mode the access <a href="#mode">mode</a>
- * @exception IllegalArgumentException if the mode argument is not equal
- * to one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or
- * <tt>"rwd"</tt>
- * @exception FileNotFoundException if the file exists but is a directory
- * rather than a regular file, or cannot be opened or
- * created for any other reason
- * @exception SecurityException if a security manager exists and its
- * <code>checkRead</code> method denies read access to the file
- * or the mode is "rw" and the security manager's
- * <code>checkWrite</code> method denies write access to the file
- * @see java.lang.SecurityException
- * @see java.lang.SecurityManager#checkRead(java.lang.String)
- * @see java.lang.SecurityManager#checkWrite(java.lang.String)
- * @revised 1.4
- * @spec JSR-51
- */
- public RandomAccessFile(String name, String mode)
- throws FileNotFoundException
- {
- this(name != null ? new File(name) : null, mode);
- }
-
- /**
- * Creates a random access file stream to read from, and optionally to
- * write to, the file specified by the {@link File} argument. A new {@link
- * FileDescriptor} object is created to represent this file connection.
- *
- * <a name="mode"><p> The <tt>mode</tt> argument specifies the access mode
- * in which the file is to be opened. The permitted values and their
- * meanings are:
- *
- * <blockquote><table summary="Access mode permitted values and meanings">
- * <tr><th><p align="left">Value</p></th><th><p align="left">Meaning</p></th></tr>
- * <tr><td valign="top"><tt>"r"</tt></td>
- * <td> Open for reading only. Invoking any of the <tt>write</tt>
- * methods of the resulting object will cause an {@link
- * java.io.IOException} to be thrown. </td></tr>
- * <tr><td valign="top"><tt>"rw"</tt></td>
- * <td> Open for reading and writing. If the file does not already
- * exist then an attempt will be made to create it. </td></tr>
- * <tr><td valign="top"><tt>"rws"</tt></td>
- * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also
- * require that every update to the file's content or metadata be
- * written synchronously to the underlying storage device. </td></tr>
- * <tr><td valign="top"><tt>"rwd" </tt></td>
- * <td> Open for reading and writing, as with <tt>"rw"</tt>, and also
- * require that every update to the file's content be written
- * synchronously to the underlying storage device. </td></tr>
- * </table></blockquote>
- *
- * The <tt>"rws"</tt> and <tt>"rwd"</tt> modes work much like the {@link
- * java.nio.channels.FileChannel#force(boolean) force(boolean)} method of
- * the {@link java.nio.channels.FileChannel} class, passing arguments of
- * <tt>true</tt> and <tt>false</tt>, respectively, except that they always
- * apply to every I/O operation and are therefore often more efficient. If
- * the file resides on a local storage device then when an invocation of a
- * method of this class returns it is guaranteed that all changes made to
- * the file by that invocation will have been written to that device. This
- * is useful for ensuring that critical information is not lost in the
- * event of a system crash. If the file does not reside on a local device
- * then no such guarantee is made.
- *
- * <p> The <tt>"rwd"</tt> mode can be used to reduce the number of I/O
- * operations performed. Using <tt>"rwd"</tt> only requires updates to the
- * file's content to be written to storage; using <tt>"rws"</tt> requires
- * updates to both the file's content and its metadata to be written, which
- * generally requires at least one more low-level I/O operation.
- *
- * <p> If there is a security manager, its <code>checkRead</code> method is
- * called with the pathname of the <code>file</code> argument as its
- * argument to see if read access to the file is allowed. If the mode
- * allows writing, the security manager's <code>checkWrite</code> method is
- * also called with the path argument to see if write access to the file is
- * allowed.
- *
- * @param file the file object
- * @param mode the access mode, as described
- * <a href="#mode">above</a>
- * @exception IllegalArgumentException if the mode argument is not equal
- * to one of <tt>"r"</tt>, <tt>"rw"</tt>, <tt>"rws"</tt>, or
- * <tt>"rwd"</tt>
- * @exception FileNotFoundException if the file exists but is a directory
- * rather than a regular file, or cannot be opened or
- * created for any other reason
- * @exception SecurityException if a security manager exists and its
- * <code>checkRead</code> method denies read access to the file
- * or the mode is "rw" and the security manager's
- * <code>checkWrite</code> method denies write access to the file
- * @see java.lang.SecurityManager#checkRead(java.lang.String)
- * @see java.lang.SecurityManager#checkWrite(java.lang.String)
- * @see java.nio.channels.FileChannel#force(boolean)
- * @revised 1.4
- * @spec JSR-51
- */
- public RandomAccessFile(File file, String mode)
- throws FileNotFoundException
- {
- String name = (file != null ? file.getPath() : null);
- int imode = -1;
- if (mode.equals("r"))
- imode = O_RDONLY;
- else if (mode.startsWith("rw")) {
- imode = O_RDWR;
- rw = true;
- if (mode.length() > 2) {
- if (mode.equals("rws"))
- imode |= O_SYNC;
- else if (mode.equals("rwd"))
- imode |= O_DSYNC;
- else
- imode = -1;
- }
- }
- if (imode < 0)
- throw new IllegalArgumentException("Illegal mode \"" + mode
- + "\" must be one of "
- + "\"r\", \"rw\", \"rws\","
- + " or \"rwd\"");
- SecurityManager security = System.getSecurityManager();
- if (security != null) {
- security.checkRead(name);
- if (rw) {
- security.checkWrite(name);
- }
- }
- if (name == null) {
- throw new NullPointerException();
- }
- fd = new FileDescriptor();
- open(name, imode);
- }
-
- /**
- * Returns the opaque file descriptor object associated with this
- * stream. </p>
- *
- * @return the file descriptor object associated with this stream.
- * @exception IOException if an I/O error occurs.
- * @see java.io.FileDescriptor
- */
- public final FileDescriptor getFD() throws IOException {
- if (fd != null) return fd;
- throw new IOException();
- }
-
- /**
- * Returns the unique {@link java.nio.channels.FileChannel FileChannel}
- * object associated with this file.
- *
- * <p> The {@link java.nio.channels.FileChannel#position()
- * </code>position<code>} of the returned channel will always be equal to
- * this object's file-pointer offset as returned by the {@link
- * #getFilePointer getFilePointer} method. Changing this object's
- * file-pointer offset, whether explicitly or by reading or writing bytes,
- * will change the position of the channel, and vice versa. Changing the
- * file's length via this object will change the length seen via the file
- * channel, and vice versa.
- *
- * @return the file channel associated with this file
- *
- * @since 1.4
- * @spec JSR-51
- */
- public final FileChannel getChannel() {
- synchronized (this) {
- if (channel == null)
- channel = FileChannelImpl.open(fd, true, rw, this);
- return channel;
- }
- }
-
- /**
- * Opens a file and returns the file descriptor. The file is
- * opened in read-write mode if writeable is true, else
- * the file is opened as read-only.
- * If the <code>name</code> refers to a directory, an IOException
- * is thrown.
- *
- * @param name the name of the file
- * @param mode the mode flags, a combination of the O_ constants
- * defined above
- */
- private native void open(String name, int mode)
- throws FileNotFoundException;
-
- // 'Read' primitives
-
- /**
- * Reads a byte of data from this file. The byte is returned as an
- * integer in the range 0 to 255 (<code>0x00-0x0ff</code>). This
- * method blocks if no input is yet available.
- * <p>
- * Although <code>RandomAccessFile</code> is not a subclass of
- * <code>InputStream</code>, this method behaves in exactly the same
- * way as the {@link InputStream#read()} method of
- * <code>InputStream</code>.
- *
- * @return the next byte of data, or <code>-1</code> if the end of the
- * file has been reached.
- * @exception IOException if an I/O error occurs. Not thrown if
- * end-of-file has been reached.
- */
- public native int read() throws IOException;
-
- /**
- * Reads a sub array as a sequence of bytes.
- * @param b the data to be written
- * @param off the start offset in the data
- * @param len the number of bytes that are written
- * @exception IOException If an I/O error has occurred.
- */
- private native int readBytes(byte b[], int off, int len) throws IOException;
-
- /**
- * Reads up to <code>len</code> bytes of data from this file into an
- * array of bytes. This method blocks until at least one byte of input
- * is available.
- * <p>
- * Although <code>RandomAccessFile</code> is not a subclass of
- * <code>InputStream</code>, this method behaves in the exactly the
- * same way as the {@link InputStream#read(byte[], int, int)} method of
- * <code>InputStream</code>.
- *
- * @param b the buffer into which the data is read.
- * @param off the start offset of the data.
- * @param len the maximum number of bytes read.
- * @return the total number of bytes read into the buffer, or
- * <code>-1</code> if there is no more data because the end of
- * the file has been reached.
- * @exception IOException if an I/O error occurs.
- */
- public int read(byte b[], int off, int len) throws IOException {
- return readBytes(b, off, len);
- }
-
- /**
- * Reads up to <code>b.length</code> bytes of data from this file
- * into an array of bytes. This method blocks until at least one byte
- * of input is available.
- * <p>
- * Although <code>RandomAccessFile</code> is not a subclass of
- * <code>InputStream</code>, this method behaves in the exactly the
- * same way as the {@link InputStream#read(byte[])} method of
- * <code>InputStream</code>.
- *
- * @param b the buffer into which the data is read.
- * @return the total number of bytes read into the buffer, or
- * <code>-1</code> if there is no more data because the end of
- * this file has been reached.
- * @exception IOException if an I/O error occurs.
- */
- public int read(byte b[]) throws IOException {
- return readBytes(b, 0, b.length);
- }
-
- /**
- * Reads <code>b.length</code> bytes from this file into the byte
- * array, starting at the current file pointer. This method reads
- * repeatedly from the file until the requested number of bytes are
- * read. This method blocks until the requested number of bytes are
- * read, the end of the stream is detected, or an exception is thrown.
- *
- * @param b the buffer into which the data is read.
- * @exception EOFException if this file reaches the end before reading
- * all the bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final void readFully(byte b[]) throws IOException {
- readFully(b, 0, b.length);
- }
-
- /**
- * Reads exactly <code>len</code> bytes from this file into the byte
- * array, starting at the current file pointer. This method reads
- * repeatedly from the file until the requested number of bytes are
- * read. This method blocks until the requested number of bytes are
- * read, the end of the stream is detected, or an exception is thrown.
- *
- * @param b the buffer into which the data is read.
- * @param off the start offset of the data.
- * @param len the number of bytes to read.
- * @exception EOFException if this file reaches the end before reading
- * all the bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final void readFully(byte b[], int off, int len) throws IOException {
- int n = 0;
- do {
- int count = this.read(b, off + n, len - n);
- if (count < 0)
- throw new EOFException();
- n += count;
- } while (n < len);
- }
-
- /**
- * Attempts to skip over <code>n</code> bytes of input discarding the
- * skipped bytes.
- * <p>
- *
- * This method may skip over some smaller number of bytes, possibly zero.
- * This may result from any of a number of conditions; reaching end of
- * file before <code>n</code> bytes have been skipped is only one
- * possibility. This method never throws an <code>EOFException</code>.
- * The actual number of bytes skipped is returned. If <code>n</code>
- * is negative, no bytes are skipped.
- *
- * @param n the number of bytes to be skipped.
- * @return the actual number of bytes skipped.
- * @exception IOException if an I/O error occurs.
- */
- public int skipBytes(int n) throws IOException {
- long pos;
- long len;
- long newpos;
-
- if (n <= 0) {
- return 0;
- }
- pos = getFilePointer();
- len = length();
- newpos = pos + n;
- if (newpos > len) {
- newpos = len;
- }
- seek(newpos);
-
- /* return the actual number of bytes skipped */
- return (int) (newpos - pos);
- }
-
- // 'Write' primitives
-
- /**
- * Writes the specified byte to this file. The write starts at
- * the current file pointer.
- *
- * @param b the <code>byte</code> to be written.
- * @exception IOException if an I/O error occurs.
- */
- public native void write(int b) throws IOException;
-
- /**
- * Writes a sub array as a sequence of bytes.
- * @param b the data to be written
-
- * @param off the start offset in the data
- * @param len the number of bytes that are written
- * @exception IOException If an I/O error has occurred.
- */
- private native void writeBytes(byte b[], int off, int len) throws IOException;
-
- /**
- * Writes <code>b.length</code> bytes from the specified byte array
- * to this file, starting at the current file pointer.
- *
- * @param b the data.
- * @exception IOException if an I/O error occurs.
- */
- public void write(byte b[]) throws IOException {
- writeBytes(b, 0, b.length);
- }
-
- /**
- * Writes <code>len</code> bytes from the specified byte array
- * starting at offset <code>off</code> to this file.
- *
- * @param b the data.
- * @param off the start offset in the data.
- * @param len the number of bytes to write.
- * @exception IOException if an I/O error occurs.
- */
- public void write(byte b[], int off, int len) throws IOException {
- writeBytes(b, off, len);
- }
-
- // 'Random access' stuff
-
- /**
- * Returns the current offset in this file.
- *
- * @return the offset from the beginning of the file, in bytes,
- * at which the next read or write occurs.
- * @exception IOException if an I/O error occurs.
- */
- public native long getFilePointer() throws IOException;
-
- /**
- * Sets the file-pointer offset, measured from the beginning of this
- * file, at which the next read or write occurs. The offset may be
- * set beyond the end of the file. Setting the offset beyond the end
- * of the file does not change the file length. The file length will
- * change only by writing after the offset has been set beyond the end
- * of the file.
- *
- * @param pos the offset position, measured in bytes from the
- * beginning of the file, at which to set the file
- * pointer.
- * @exception IOException if <code>pos</code> is less than
- * <code>0</code> or if an I/O error occurs.
- */
- public native void seek(long pos) throws IOException;
-
- /**
- * Returns the length of this file.
- *
- * @return the length of this file, measured in bytes.
- * @exception IOException if an I/O error occurs.
- */
- public native long length() throws IOException;
-
- /**
- * Sets the length of this file.
- *
- * <p> If the present length of the file as returned by the
- * <code>length</code> method is greater than the <code>newLength</code>
- * argument then the file will be truncated. In this case, if the file
- * offset as returned by the <code>getFilePointer</code> method is greater
- * then <code>newLength</code> then after this method returns the offset
- * will be equal to <code>newLength</code>.
- *
- * <p> If the present length of the file as returned by the
- * <code>length</code> method is smaller than the <code>newLength</code>
- * argument then the file will be extended. In this case, the contents of
- * the extended portion of the file are not defined.
- *
- * @param newLength The desired length of the file
- * @exception IOException If an I/O error occurs
- * @since 1.2
- */
- public native void setLength(long newLength) throws IOException;
-
- /**
- * Closes this random access file stream and releases any system
- * resources associated with the stream. A closed random access
- * file cannot perform input or output operations and cannot be
- * reopened.
- *
- * <p> If this file has an associated channel then the channel is closed
- * as well.
- *
- * @exception IOException if an I/O error occurs.
- *
- * @revised 1.4
- * @spec JSR-51
- */
- public void close() throws IOException {
- if (channel != null)
- channel.close();
- close0();
- }
-
- //
- // Some "reading/writing Java data types" methods stolen from
- // DataInputStream and DataOutputStream.
- //
-
- /**
- * Reads a <code>boolean</code> from this file. This method reads a
- * single byte from the file, starting at the current file pointer.
- * A value of <code>0</code> represents
- * <code>false</code>. Any other value represents <code>true</code>.
- * This method blocks until the byte is read, the end of the stream
- * is detected, or an exception is thrown.
- *
- * @return the <code>boolean</code> value read.
- * @exception EOFException if this file has reached the end.
- * @exception IOException if an I/O error occurs.
- */
- public final boolean readBoolean() throws IOException {
- int ch = this.read();
- if (ch < 0)
- throw new EOFException();
- return (ch != 0);
- }
-
- /**
- * Reads a signed eight-bit value from this file. This method reads a
- * byte from the file, starting from the current file pointer.
- * If the byte read is <code>b</code>, where
- * <code>0 <= b <= 255</code>,
- * then the result is:
- * <blockquote><pre>
- * (byte)(b)
- * </pre></blockquote>
- * <p>
- * This method blocks until the byte is read, the end of the stream
- * is detected, or an exception is thrown.
- *
- * @return the next byte of this file as a signed eight-bit
- * <code>byte</code>.
- * @exception EOFException if this file has reached the end.
- * @exception IOException if an I/O error occurs.
- */
- public final byte readByte() throws IOException {
- int ch = this.read();
- if (ch < 0)
- throw new EOFException();
- return (byte)(ch);
- }
-
- /**
- * Reads an unsigned eight-bit number from this file. This method reads
- * a byte from this file, starting at the current file pointer,
- * and returns that byte.
- * <p>
- * This method blocks until the byte is read, the end of the stream
- * is detected, or an exception is thrown.
- *
- * @return the next byte of this file, interpreted as an unsigned
- * eight-bit number.
- * @exception EOFException if this file has reached the end.
- * @exception IOException if an I/O error occurs.
- */
- public final int readUnsignedByte() throws IOException {
- int ch = this.read();
- if (ch < 0)
- throw new EOFException();
- return ch;
- }
-
- /**
- * Reads a signed 16-bit number from this file. The method reads two
- * bytes from this file, starting at the current file pointer.
- * If the two bytes read, in order, are
- * <code>b1</code> and <code>b2</code>, where each of the two values is
- * between <code>0</code> and <code>255</code>, inclusive, then the
- * result is equal to:
- * <blockquote><pre>
- * (short)((b1 << 8) | b2)
- * </pre></blockquote>
- * <p>
- * This method blocks until the two bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next two bytes of this file, interpreted as a signed
- * 16-bit number.
- * @exception EOFException if this file reaches the end before reading
- * two bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final short readShort() throws IOException {
- int ch1 = this.read();
- int ch2 = this.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (short)((ch1 << 8) + (ch2 << 0));
- }
-
- /**
- * Reads an unsigned 16-bit number from this file. This method reads
- * two bytes from the file, starting at the current file pointer.
- * If the bytes read, in order, are
- * <code>b1</code> and <code>b2</code>, where
- * <code>0 <= b1, b2 <= 255</code>,
- * then the result is equal to:
- * <blockquote><pre>
- * (b1 << 8) | b2
- * </pre></blockquote>
- * <p>
- * This method blocks until the two bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next two bytes of this file, interpreted as an unsigned
- * 16-bit integer.
- * @exception EOFException if this file reaches the end before reading
- * two bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final int readUnsignedShort() throws IOException {
- int ch1 = this.read();
- int ch2 = this.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (ch1 << 8) + (ch2 << 0);
- }
-
- /**
- * Reads a Unicode character from this file. This method reads two
- * bytes from the file, starting at the current file pointer.
- * If the bytes read, in order, are
- * <code>b1</code> and <code>b2</code>, where
- * <code>0 <= b1, b2 <= 255</code>,
- * then the result is equal to:
- * <blockquote><pre>
- * (char)((b1 << 8) | b2)
- * </pre></blockquote>
- * <p>
- * This method blocks until the two bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next two bytes of this file as a Unicode character.
- * @exception EOFException if this file reaches the end before reading
- * two bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final char readChar() throws IOException {
- int ch1 = this.read();
- int ch2 = this.read();
- if ((ch1 | ch2) < 0)
- throw new EOFException();
- return (char)((ch1 << 8) + (ch2 << 0));
- }
-
- /**
- * Reads a signed 32-bit integer from this file. This method reads 4
- * bytes from the file, starting at the current file pointer.
- * If the bytes read, in order, are <code>b1</code>,
- * <code>b2</code>, <code>b3</code>, and <code>b4</code>, where
- * <code>0 <= b1, b2, b3, b4 <= 255</code>,
- * then the result is equal to:
- * <blockquote><pre>
- * (b1 << 24) | (b2 << 16) + (b3 << 8) + b4
- * </pre></blockquote>
- * <p>
- * This method blocks until the four bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next four bytes of this file, interpreted as an
- * <code>int</code>.
- * @exception EOFException if this file reaches the end before reading
- * four bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final int readInt() throws IOException {
- int ch1 = this.read();
- int ch2 = this.read();
- int ch3 = this.read();
- int ch4 = this.read();
- if ((ch1 | ch2 | ch3 | ch4) < 0)
- throw new EOFException();
- return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
- }
-
- /**
- * Reads a signed 64-bit integer from this file. This method reads eight
- * bytes from the file, starting at the current file pointer.
- * If the bytes read, in order, are
- * <code>b1</code>, <code>b2</code>, <code>b3</code>,
- * <code>b4</code>, <code>b5</code>, <code>b6</code>,
- * <code>b7</code>, and <code>b8,</code> where:
- * <blockquote><pre>
- * 0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,
- * </pre></blockquote>
- * <p>
- * then the result is equal to:
- * <p><blockquote><pre>
- * ((long)b1 << 56) + ((long)b2 << 48)
- * + ((long)b3 << 40) + ((long)b4 << 32)
- * + ((long)b5 << 24) + ((long)b6 << 16)
- * + ((long)b7 << 8) + b8
- * </pre></blockquote>
- * <p>
- * This method blocks until the eight bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next eight bytes of this file, interpreted as a
- * <code>long</code>.
- * @exception EOFException if this file reaches the end before reading
- * eight bytes.
- * @exception IOException if an I/O error occurs.
- */
- public final long readLong() throws IOException {
- return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
- }
-
- /**
- * Reads a <code>float</code> from this file. This method reads an
- * <code>int</code> value, starting at the current file pointer,
- * as if by the <code>readInt</code> method
- * and then converts that <code>int</code> to a <code>float</code>
- * using the <code>intBitsToFloat</code> method in class
- * <code>Float</code>.
- * <p>
- * This method blocks until the four bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next four bytes of this file, interpreted as a
- * <code>float</code>.
- * @exception EOFException if this file reaches the end before reading
- * four bytes.
- * @exception IOException if an I/O error occurs.
- * @see java.io.RandomAccessFile#readInt()
- * @see java.lang.Float#intBitsToFloat(int)
- */
- public final float readFloat() throws IOException {
- return Float.intBitsToFloat(readInt());
- }
-
- /**
- * Reads a <code>double</code> from this file. This method reads a
- * <code>long</code> value, starting at the current file pointer,
- * as if by the <code>readLong</code> method
- * and then converts that <code>long</code> to a <code>double</code>
- * using the <code>longBitsToDouble</code> method in
- * class <code>Double</code>.
- * <p>
- * This method blocks until the eight bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return the next eight bytes of this file, interpreted as a
- * <code>double</code>.
- * @exception EOFException if this file reaches the end before reading
- * eight bytes.
- * @exception IOException if an I/O error occurs.
- * @see java.io.RandomAccessFile#readLong()
- * @see java.lang.Double#longBitsToDouble(long)
- */
- public final double readDouble() throws IOException {
- return Double.longBitsToDouble(readLong());
- }
-
- /**
- * Reads the next line of text from this file. This method successively
- * reads bytes from the file, starting at the current file pointer,
- * until it reaches a line terminator or the end
- * of the file. Each byte is converted into a character by taking the
- * byte's value for the lower eight bits of the character and setting the
- * high eight bits of the character to zero. This method does not,
- * therefore, support the full Unicode character set.
- *
- * <p> A line of text is terminated by a carriage-return character
- * (<code>'\r'</code>), a newline character (<code>'\n'</code>), a
- * carriage-return character immediately followed by a newline character,
- * or the end of the file. Line-terminating characters are discarded and
- * are not included as part of the string returned.
- *
- * <p> This method blocks until a newline character is read, a carriage
- * return and the byte following it are read (to see if it is a newline),
- * the end of the file is reached, or an exception is thrown.
- *
- * @return the next line of text from this file, or null if end
- * of file is encountered before even one byte is read.
- * @exception IOException if an I/O error occurs.
- */
-
- public final String readLine() throws IOException {
- StringBuffer input = new StringBuffer();
- int c = -1;
- boolean eol = false;
-
- while (!eol) {
- switch (c = read()) {
- case -1:
- case '\n':
- eol = true;
- break;
- case '\r':
- eol = true;
- long cur = getFilePointer();
- if ((read()) != '\n') {
- seek(cur);
- }
- break;
- default:
- input.append((char)c);
- break;
- }
- }
-
- if ((c == -1) && (input.length() == 0)) {
- return null;
- }
- return input.toString();
- }
-
- /**
- * Reads in a string from this file. The string has been encoded
- * using a modified UTF-8 format.
- * <p>
- * The first two bytes are read, starting from the current file
- * pointer, as if by
- * <code>readUnsignedShort</code>. This value gives the number of
- * following bytes that are in the encoded string, not
- * the length of the resulting string. The following bytes are then
- * interpreted as bytes encoding characters in the UTF-8 format
- * and are converted into characters.
- * <p>
- * This method blocks until all the bytes are read, the end of the
- * stream is detected, or an exception is thrown.
- *
- * @return a Unicode string.
- * @exception EOFException if this file reaches the end before
- * reading all the bytes.
- * @exception IOException if an I/O error occurs.
- * @exception UTFDataFormatException if the bytes do not represent
- * valid UTF-8 encoding of a Unicode string.
- * @see java.io.RandomAccessFile#readUnsignedShort()
- */
- public final String readUTF() throws IOException {
- return DataInputStream.readUTF(this);
- }
-
- /**
- * Writes a <code>boolean</code> to the file as a one-byte value. The
- * value <code>true</code> is written out as the value
- * <code>(byte)1</code> the value <code>false</code> is written out
- * as the value <code>(byte)0</code>. The write starts at
- * the current position of the file pointer.
- *
- * @param v a <code>boolean</code> value to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeBoolean(boolean v) throws IOException {
- write(v ? 1 : 0);
- //written++;
- }
-
- /**
- * Writes a <code>byte</code> to the file as a one-byte value. The
- * write starts at the current position of the file pointer.
- *
- * @param v a <code>byte</code> value to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeByte(int v) throws IOException {
- write(v);
- //written++;
- }
-
- /**
- * Writes a <code>short</code> to the file as two bytes, high byte first.
- * The write starts at the current position of the file pointer.
- *
- * @param v a <code>short</code> to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeShort(int v) throws IOException {
- write((v >>> 8) & 0xFF);
- write((v >>> 0) & 0xFF);
- //written += 2;
- }
-
- /**
- * Writes a <code>char</code> to the file as a two-byte value, high
- * byte first. The write starts at the current position of the
- * file pointer.
- *
- * @param v a <code>char</code> value to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeChar(int v) throws IOException {
- write((v >>> 8) & 0xFF);
- write((v >>> 0) & 0xFF);
- //written += 2;
- }
-
- /**
- * Writes an <code>int</code> to the file as four bytes, high byte first.
- * The write starts at the current position of the file pointer.
- *
- * @param v an <code>int</code> to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeInt(int v) throws IOException {
- write((v >>> 24) & 0xFF);
- write((v >>> 16) & 0xFF);
- write((v >>> 8) & 0xFF);
- write((v >>> 0) & 0xFF);
- //written += 4;
- }
-
- /**
- * Writes a <code>long</code> to the file as eight bytes, high byte first.
- * The write starts at the current position of the file pointer.
- *
- * @param v a <code>long</code> to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeLong(long v) throws IOException {
- write((int)(v >>> 56) & 0xFF);
- write((int)(v >>> 48) & 0xFF);
- write((int)(v >>> 40) & 0xFF);
- write((int)(v >>> 32) & 0xFF);
- write((int)(v >>> 24) & 0xFF);
- write((int)(v >>> 16) & 0xFF);
- write((int)(v >>> 8) & 0xFF);
- write((int)(v >>> 0) & 0xFF);
- //written += 8;
- }
-
- /**
- * Converts the float argument to an <code>int</code> using the
- * <code>floatToIntBits</code> method in class <code>Float</code>,
- * and then writes that <code>int</code> value to the file as a
- * four-byte quantity, high byte first. The write starts at the
- * current position of the file pointer.
- *
- * @param v a <code>float</code> value to be written.
- * @exception IOException if an I/O error occurs.
- * @see java.lang.Float#floatToIntBits(float)
- */
- public final void writeFloat(float v) throws IOException {
- writeInt(Float.floatToIntBits(v));
- }
-
- /**
- * Converts the double argument to a <code>long</code> using the
- * <code>doubleToLongBits</code> method in class <code>Double</code>,
- * and then writes that <code>long</code> value to the file as an
- * eight-byte quantity, high byte first. The write starts at the current
- * position of the file pointer.
- *
- * @param v a <code>double</code> value to be written.
- * @exception IOException if an I/O error occurs.
- * @see java.lang.Double#doubleToLongBits(double)
- */
- public final void writeDouble(double v) throws IOException {
- writeLong(Double.doubleToLongBits(v));
- }
-
- /**
- * Writes the string to the file as a sequence of bytes. Each
- * character in the string is written out, in sequence, by discarding
- * its high eight bits. The write starts at the current position of
- * the file pointer.
- *
- * @param s a string of bytes to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeBytes(String s) throws IOException {
- int len = s.length();
- byte[] b = new byte[len];
- s.getBytes(0, len, b, 0);
- writeBytes(b, 0, len);
- }
-
- /**
- * Writes a string to the file as a sequence of characters. Each
- * character is written to the data output stream as if by the
- * <code>writeChar</code> method. The write starts at the current
- * position of the file pointer.
- *
- * @param s a <code>String</code> value to be written.
- * @exception IOException if an I/O error occurs.
- * @see java.io.RandomAccessFile#writeChar(int)
- */
- public final void writeChars(String s) throws IOException {
- int clen = s.length();
- int blen = 2*clen;
- byte[] b = new byte[blen];
- char[] c = new char[clen];
- s.getChars(0, clen, c, 0);
- for (int i = 0, j = 0; i < clen; i++) {
- b[j++] = (byte)(c[i] >>> 8);
- b[j++] = (byte)(c[i] >>> 0);
- }
- writeBytes(b, 0, blen);
- }
-
- /**
- * Writes a string to the file using UTF-8 encoding in a
- * machine-independent manner.
- * <p>
- * First, two bytes are written to the file, starting at the
- * current file pointer, as if by the
- * <code>writeShort</code> method giving the number of bytes to
- * follow. This value is the number of bytes actually written out,
- * not the length of the string. Following the length, each character
- * of the string is output, in sequence, using the UTF-8 encoding
- * for each character.
- *
- * @param str a string to be written.
- * @exception IOException if an I/O error occurs.
- */
- public final void writeUTF(String str) throws IOException {
- DataOutputStream.writeUTF(str, this);
- }
-
- private static native void initIDs();
-
- private native void close0() throws IOException;
-
- static {
- initIDs();
- }
-
- }