| /* |
| |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| |
| */ |
| package org.apache.batik.ext.awt.image.codec.util; |
| |
| import java.io.DataInput; |
| import java.io.DataInputStream; |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.UTFDataFormatException; |
| |
| /** |
| * An abstract subclass of <code>java.io.InputStream</code> that allows seeking |
| * within the input, similar to the <code>RandomAccessFile</code> class. |
| * Additionally, the <code>DataInput</code> interface is supported and extended |
| * to include support for little-endian representations of fundamental data |
| * types. |
| * |
| * <p> In addition to the familiar methods from <code>InputStream</code>, the |
| * methods <code>getFilePointer()</code>, <code>seek()</code>, are defined as in |
| * the <code>RandomAccessFile</code> class. The <code>canSeekBackwards()</code> |
| * method will return <code>true</code> if it is permissible to seek to a |
| * position earlier in the stream than the current value of |
| * <code>getFilePointer()</code>. Some subclasses of |
| * <code>SeekableStream</code> guarantee the ability to seek backwards while |
| * others may not offer this feature in the interest of providing greater |
| * efficiency for those users who do not require it. |
| * |
| * <p> The <code>DataInput</code> interface is supported as well. This included |
| * the <code>skipBytes()</code> and <code>readFully()</code> methods and a |
| * variety of <code>read</code> methods for various data types. |
| * |
| * <p> A number of concrete subclasses of <code>SeekableStream</code> are |
| * supplied in the <code>com.sun.media.jai.codec</code> package. |
| * |
| * <p> Three classes are provided for the purpose of adapting a standard |
| * <code>InputStream</code> to the <code>SeekableStream</code> interface. |
| * <code>ForwardSeekableStream</code> does not allows seeking backwards, but is |
| * inexpensive to use. <code>FileCacheSeekableStream</code> maintains a copy of |
| * all of the data read from the input in a temporary file; this file will be |
| * discarded automatically when the <code>FileSeekableStream</code> is |
| * finalized, or when the JVM exits normally. |
| * <code>FileCacheSeekableStream</code> is intended to be reasonably efficient |
| * apart from the unavoidable use of disk space. In circumstances where the |
| * creation of a temporary file is not possible, |
| * <code>MemoryCacheSeekableStream</code> may be used. |
| * <code>MemoryCacheSeekableStream</code> creates a potentially large in-memory |
| * buffer to store the stream data and so should be avoided when possible. |
| * |
| * <p> The <code>FileSeekableStream</code> class wraps a <code>File</code> or |
| * <code>RandomAccessFile</code>. It forwards requests to the real underlying |
| * file. It performs a limited amount of caching in order to avoid excessive |
| * I/O costs. |
| * |
| * <p> The <code>SegmentedSeekableStream</code> class performs a different sort |
| * of function. It creates a <code>SeekableStream</code> from another |
| * <code>SeekableStream</code> by selecting a series of portions or "segments". |
| * Each segment starts at a specified location within the source |
| * <code>SeekableStream</code> and extends for a specified number of bytes. The |
| * <code>StreamSegmentMapper</code> interface and <code>StreamSegment</code> |
| * class may be used to compute the segment positions dynamically. |
| * |
| * <p> A convenience methods, <code>wrapInputStream</code> is provided to |
| * construct a suitable <code>SeekableStream</code> instance whose data is |
| * supplied by a given <code>InputStream</code>. The caller, by means of the |
| * <code>canSeekBackwards</code> parameter, determines whether support for |
| * seeking backwards is required. |
| * |
| * @version $Id$ |
| */ |
| public abstract class SeekableStream extends InputStream implements DataInput { |
| |
| /** |
| * Returns a <code>SeekableStream</code> that will read from a |
| * given <code>InputStream</code>, optionally including support |
| * for seeking backwards. This is a convenience method that |
| * avoids the need to instantiate specific subclasses of |
| * <code>SeekableStream</code> depending on the current security |
| * model. |
| * |
| * @param is An <code>InputStream</code>. |
| * @param canSeekBackwards <code>true</code> if the ability to seek |
| * backwards in the output is required. |
| * @return An instance of <code>SeekableStream</code>. |
| */ |
| public static SeekableStream wrapInputStream(InputStream is, |
| boolean canSeekBackwards) { |
| SeekableStream stream = null; |
| |
| if (canSeekBackwards) { |
| try { |
| stream = new FileCacheSeekableStream(is); |
| } catch (Exception e) { |
| stream = new MemoryCacheSeekableStream(is); |
| } |
| } else { |
| stream = new ForwardSeekableStream(is); |
| } |
| return stream; |
| } |
| |
| // Methods from InputStream |
| |
| /** |
| * Reads the next byte of data from the input stream. The value byte is |
| * returned as an <code>int</code> in the range <code>0</code> to |
| * <code>255</code>. If no byte is available because the end of the stream |
| * has been reached, the value <code>-1</code> is returned. This method |
| * blocks until input data is available, the end of the stream is detected, |
| * or an exception is thrown. |
| * |
| * <p> A subclass must provide an implementation of this method. |
| * |
| * @return the next byte of data, or <code>-1</code> if the end of the |
| * stream is reached. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public abstract int read() throws IOException; |
| |
| /** |
| * Reads up to <code>len</code> bytes of data from the input stream into |
| * an array of bytes. An attempt is made to read as many as |
| * <code>len</code> bytes, but a smaller number may be read, possibly |
| * zero. The number of bytes actually read is returned as an integer. |
| * |
| * <p> This method blocks until input data is available, end of stream is |
| * detected, or an exception is thrown. |
| * |
| * <p> If <code>b</code> is <code>null</code>, a |
| * <code>NullPointerException</code> is thrown. |
| * |
| * <p> If <code>off</code> is negative, or <code>len</code> is negative, or |
| * <code>off+len</code> is greater than the length of the array |
| * <code>b</code>, then an <code>IndexOutOfBoundsException</code> is |
| * thrown. |
| * |
| * <p> If <code>len</code> is zero, then no bytes are read and |
| * <code>0</code> is returned; otherwise, there is an attempt to read at |
| * least one byte. If no byte is available because the stream is at end of |
| * stream, the value <code>-1</code> is returned; otherwise, at least one |
| * byte is read and stored into <code>b</code>. |
| * |
| * <p> The first byte read is stored into element <code>b[off]</code>, the |
| * next one into <code>b[off+1]</code>, and so on. The number of bytes read |
| * is, at most, equal to <code>len</code>. Let <i>k</i> be the number of |
| * bytes actually read; these bytes will be stored in elements |
| * <code>b[off]</code> through <code>b[off+</code><i>k</i><code>-1]</code>, |
| * leaving elements <code>b[off+</code><i>k</i><code>]</code> through |
| * <code>b[off+len-1]</code> unaffected. |
| * |
| * <p> In every case, elements <code>b[0]</code> through |
| * <code>b[off]</code> and elements <code>b[off+len]</code> through |
| * <code>b[b.length-1]</code> are unaffected. |
| * |
| * <p> If the first byte cannot be read for any reason other than end of |
| * stream, then an <code>IOException</code> is thrown. In particular, an |
| * <code>IOException</code> is thrown if the input stream has been closed. |
| * |
| * <p> A subclass must provide an implementation of this method. |
| * |
| * @param b the buffer into which the data is read. |
| * @param off the start offset in array <code>b</code> |
| * at which the data is written. |
| * @param len the maximum number of bytes to 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 stream has been reached. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public abstract int read(byte[] b, int off, int len) throws IOException; |
| |
| // Implemented in InputStream: |
| // |
| // public int read(byte[] b) throws IOException { |
| // public long skip(long n) throws IOException |
| // public int available) throws IOException |
| // public void close() throws IOException; |
| |
| /** Marked position, shared by {@link ForwardSeekableStream} */ |
| protected long markPos = -1L; |
| |
| /** |
| * Marks the current file position for later return using |
| * the <code>reset()</code> method. |
| */ |
| public synchronized void mark(int readLimit) { |
| try { |
| markPos = getFilePointer(); |
| } catch (IOException e) { |
| markPos = -1L; |
| } |
| } |
| |
| /** |
| * Returns the file position to its position at the time of |
| * the immediately previous call to the <code>mark()</code> |
| * method. |
| */ |
| public synchronized void reset() throws IOException { |
| if (markPos != -1) { |
| seek(markPos); |
| } |
| } |
| |
| /** |
| * Returns <code>true</code> if marking is supported. |
| * Marking is automatically supported for <code>SeekableStream</code> |
| * subclasses that support seeking backeards. Subclasses that do |
| * not support seeking backwards but do support marking must override |
| * this method. |
| */ |
| public boolean markSupported() { |
| return canSeekBackwards(); |
| } |
| |
| /** |
| * Returns <code>true</code> if this object supports calls to |
| * <code>seek(pos)</code> with an offset <code>pos</code> smaller |
| * than the current offset, as returned by <code>getFilePointer</code>. |
| */ |
| public boolean canSeekBackwards() { |
| return false; |
| } |
| |
| /** |
| * Returns the current offset in this stream. |
| * |
| * @return the offset from the beginning of the stream, in bytes, |
| * at which the next read occurs. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public abstract long getFilePointer() throws IOException; |
| |
| /** |
| * Sets the offset, measured from the beginning of this |
| * stream, at which the next read occurs. |
| * |
| * <p> If <code>canSeekBackwards()</code> returns <code>false</code>, |
| * then setting <code>pos</code> to an offset smaller than |
| * the current value of <code>getFilePointer()</code> will have |
| * no effect. |
| * |
| * @param pos the offset position, measured in bytes from the |
| * beginning of the stream, at which to set the stream |
| * pointer. |
| * @exception IOException if <code>pos</code> is less than |
| * <code>0</code> or if an I/O error occurs. |
| */ |
| public abstract void seek(long pos) throws IOException; |
| |
| // Methods from RandomAccessFile |
| |
| /** |
| * Reads <code>b.length</code> bytes from this stream into the byte |
| * array, starting at the current stream pointer. This method reads |
| * repeatedly from the stream 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 stream 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 stream into the byte |
| * array, starting at the current stream pointer. This method reads |
| * repeatedly from the stream 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 stream 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); |
| } |
| |
| // Methods from DataInput, plus little-endian versions |
| |
| /** |
| * 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 |
| * stream 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 { |
| if (n <= 0) { |
| return 0; |
| } |
| return (int)skip(n); |
| } |
| |
| /** |
| * Reads a <code>boolean</code> from this stream. This method reads a |
| * single byte from the stream, starting at the current stream 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 stream 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 stream. This method reads a |
| * byte from the stream, starting from the current stream 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 stream as a signed eight-bit |
| * <code>byte</code>. |
| * @exception EOFException if this stream 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 stream. This method reads |
| * a byte from this stream, starting at the current stream 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 stream, interpreted as an unsigned |
| * eight-bit number. |
| * @exception EOFException if this stream 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 stream. |
| * The method reads two |
| * bytes from this stream, starting at the current stream 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 stream, interpreted as a signed |
| * 16-bit number. |
| * @exception EOFException if this stream 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 a signed 16-bit number from this stream in little-endian order. |
| * The method reads two |
| * bytes from this stream, starting at the current stream 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)((b2 << 8) | b1) |
| * </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 stream, interpreted as a signed |
| * 16-bit number. |
| * @exception EOFException if this stream reaches the end before reading |
| * two bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final short readShortLE() throws IOException { |
| int ch1 = this.read(); |
| int ch2 = this.read(); |
| if ((ch1 | ch2) < 0) |
| throw new EOFException(); |
| return (short)((ch2 << 8) + (ch1 << 0)); |
| } |
| |
| /** |
| * Reads an unsigned 16-bit number from this stream. This method reads |
| * two bytes from the stream, starting at the current stream 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 stream, interpreted as an |
| * unsigned 16-bit integer. |
| * @exception EOFException if this stream 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 an unsigned 16-bit number from this stream in little-endian order. |
| * This method reads |
| * two bytes from the stream, starting at the current stream 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> |
| * (b2 << 8) | b1 |
| * </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 stream, interpreted as an |
| * unsigned 16-bit integer. |
| * @exception EOFException if this stream reaches the end before reading |
| * two bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final int readUnsignedShortLE() throws IOException { |
| int ch1 = this.read(); |
| int ch2 = this.read(); |
| if ((ch1 | ch2) < 0) |
| throw new EOFException(); |
| return (ch2 << 8) + (ch1 << 0); |
| } |
| |
| /** |
| * Reads a Unicode character from this stream. This method reads two |
| * bytes from the stream, starting at the current stream 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 stream as a Unicode character. |
| * @exception EOFException if this stream 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 Unicode character from this stream in little-endian order. |
| * This method reads two |
| * bytes from the stream, starting at the current stream 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)((b2 << 8) | b1) |
| * </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 stream as a Unicode character. |
| * @exception EOFException if this stream reaches the end before reading |
| * two bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final char readCharLE() throws IOException { |
| int ch1 = this.read(); |
| int ch2 = this.read(); |
| if ((ch1 | ch2) < 0) |
| throw new EOFException(); |
| return (char)((ch2 << 8) + (ch1 << 0)); |
| } |
| |
| /** |
| * Reads a signed 32-bit integer from this stream. This method reads 4 |
| * bytes from the stream, starting at the current stream 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 stream, interpreted as an |
| * <code>int</code>. |
| * @exception EOFException if this stream 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 32-bit integer from this stream in little-endian order. |
| * This method reads 4 |
| * bytes from the stream, starting at the current stream 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> |
| * (b4 << 24) | (b3 << 16) + (b2 << 8) + b1 |
| * </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 stream, interpreted as an |
| * <code>int</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * four bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final int readIntLE() 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 ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0)); |
| } |
| |
| /** |
| * Reads an unsigned 32-bit integer from this stream. This method reads 4 |
| * bytes from the stream, starting at the current stream 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 stream, interpreted as a |
| * <code>long</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * four bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final long readUnsignedInt() throws IOException { |
| long ch1 = this.read(); |
| long ch2 = this.read(); |
| long ch3 = this.read(); |
| long ch4 = this.read(); |
| if ((ch1 | ch2 | ch3 | ch4) < 0) |
| throw new EOFException(); |
| return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0)); |
| } |
| |
| private byte[] ruileBuf = new byte[4]; |
| |
| /** |
| * Reads an unsigned 32-bit integer from this stream in little-endian |
| * order. This method reads 4 |
| * bytes from the stream, starting at the current stream 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> |
| * (b4 << 24) | (b3 << 16) + (b2 << 8) + b1 |
| * </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 stream, interpreted as a |
| * <code>long</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * four bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final long readUnsignedIntLE() throws IOException { |
| this.readFully(ruileBuf); |
| long ch1 = (ruileBuf[0] & 0xff); |
| long ch2 = (ruileBuf[1] & 0xff); |
| long ch3 = (ruileBuf[2] & 0xff); |
| long ch4 = (ruileBuf[3] & 0xff); |
| |
| return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0)); |
| } |
| |
| /** |
| * Reads a signed 64-bit integer from this stream. This method reads eight |
| * bytes from the stream, starting at the current stream 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 stream, interpreted as a |
| * <code>long</code>. |
| * @exception EOFException if this stream 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 signed 64-bit integer from this stream in little-endian |
| * order. This method reads eight |
| * bytes from the stream, starting at the current stream 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 stream, interpreted as a |
| * <code>long</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * eight bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final long readLongLE() throws IOException { |
| int i1 = readIntLE(); |
| int i2 = readIntLE(); |
| return ((long)i2 << 32) + (i1 & 0xFFFFFFFFL); |
| } |
| |
| /** |
| * Reads a <code>float</code> from this stream. This method reads an |
| * <code>int</code> value, starting at the current stream 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 stream, interpreted as a |
| * <code>float</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * four bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final float readFloat() throws IOException { |
| return Float.intBitsToFloat(readInt()); |
| } |
| |
| /** |
| * Reads a <code>float</code> from this stream in little-endian order. |
| * This method reads an |
| * <code>int</code> value, starting at the current stream 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 stream, interpreted as a |
| * <code>float</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * four bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final float readFloatLE() throws IOException { |
| return Float.intBitsToFloat(readIntLE()); |
| } |
| |
| /** |
| * Reads a <code>double</code> from this stream. This method reads a |
| * <code>long</code> value, starting at the current stream 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 stream, interpreted as a |
| * <code>double</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * eight bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final double readDouble() throws IOException { |
| return Double.longBitsToDouble(readLong()); |
| } |
| |
| /** |
| * Reads a <code>double</code> from this stream in little-endian order. |
| * This method reads a |
| * <code>long</code> value, starting at the current stream 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 stream, interpreted as a |
| * <code>double</code>. |
| * @exception EOFException if this stream reaches the end before reading |
| * eight bytes. |
| * @exception IOException if an I/O error occurs. |
| */ |
| public final double readDoubleLE() throws IOException { |
| return Double.longBitsToDouble(readLongLE()); |
| } |
| |
| /** |
| * Reads the next line of text from this stream. This method successively |
| * reads bytes from the stream, starting at the current stream pointer, |
| * until it reaches a line terminator or the end |
| * of the stream. 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 stream. 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 stream is reached, or an exception is thrown. |
| * |
| * @return the next line of text from this stream, or null if end |
| * of stream 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 stream. The string has been encoded |
| * using a modified UTF-8 format. |
| * <p> |
| * The first two bytes are read, starting from the current stream |
| * 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 stream 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. |
| */ |
| public final String readUTF() throws IOException { |
| return DataInputStream.readUTF(this); |
| } |
| |
| /** |
| * Releases any system resources associated with this stream |
| * by calling the <code>close()</code> method. |
| */ |
| protected void finalize() throws Throwable { |
| super.finalize(); |
| close(); |
| } |
| } |