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/* * @(#)FileCacheImageOutputStream.java 1.26 06/01/05 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package javax.imageio.stream; import java.io.DataInput; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.OutputStream; import java.io.RandomAccessFile; import com.sun.imageio.stream.StreamCloser; /** * An implementation of <code>ImageOutputStream</code> that writes its * output to a regular <code>OutputStream</code>. A file is used to * cache data until it is flushed to the output stream. * * @version 0.5 */ public class FileCacheImageOutputStream extends ImageOutputStreamImpl { private OutputStream stream; private File cacheFile; private RandomAccessFile cache; // Pos after last (rightmost) byte written private long maxStreamPos = 0L; /** * Constructs a <code>FileCacheImageOutputStream</code> that will write * to a given <code>outputStream</code>. * * <p> A temporary file is used as a cache. If * <code>cacheDir</code>is non-<code>null</code> and is a * directory, the file will be created there. If it is * <code>null</code>, the system-dependent default temporary-file * directory will be used (see the documentation for * <code>File.createTempFile</code> for details). * * @param stream an <code>OutputStream</code> to write to. * @param cacheDir a <code>File</code> indicating where the * cache file should be created, or <code>null</code> to use the * system directory. * * @exception IllegalArgumentException if <code>stream</code> * is <code>null</code>. * @exception IllegalArgumentException if <code>cacheDir</code> is * non-<code>null</code> but is not a directory. * @exception IOException if a cache file cannot be created. */ public FileCacheImageOutputStream(OutputStream stream, File cacheDir) throws IOException { if (stream == null) { throw new IllegalArgumentException("stream == null!"); } if ((cacheDir != null) && !(cacheDir.isDirectory())) { throw new IllegalArgumentException("Not a directory!"); } this.stream = stream; this.cacheFile = File.createTempFile("imageio", ".tmp", cacheDir); this.cache = new RandomAccessFile(cacheFile, "rw"); StreamCloser.addToQueue(this); } public int read() throws IOException { checkClosed(); bitOffset = 0; int val = cache.read(); if (val != -1) { ++streamPos; } return val; } public int read(byte[] b, int off, int len) throws IOException { checkClosed(); if (b == null) { throw new NullPointerException("b == null!"); } if (off < 0 || len < 0 || off + len > b.length || off + len < 0) { throw new IndexOutOfBoundsException ("off < 0 || len < 0 || off+len > b.length || off+len < 0!"); } bitOffset = 0; if (len == 0) { return 0; } int nbytes = cache.read(b, off, len); if (nbytes != -1) { streamPos += nbytes; } return nbytes; } public void write(int b) throws IOException { flushBits(); // this will call checkClosed() for us cache.write(b); ++streamPos; maxStreamPos = Math.max(maxStreamPos, streamPos); } public void write(byte[] b, int off, int len) throws IOException { flushBits(); // this will call checkClosed() for us cache.write(b, off, len); streamPos += len; maxStreamPos = Math.max(maxStreamPos, streamPos); } public long length() { try { checkClosed(); return cache.length(); } catch (IOException e) { return -1L; } } /** * Sets the current stream position and resets the bit offset to * 0. It is legal to seek past the end of the file; an * <code>EOFException</code> will be thrown only if a read is * performed. The file length will not be increased until a write * is performed. * * @exception IndexOutOfBoundsException if <code>pos</code> is smaller * than the flushed position. * @exception IOException if any other I/O error occurs. */ public void seek(long pos) throws IOException { checkClosed(); if (pos < flushedPos) { throw new IndexOutOfBoundsException(); } cache.seek(pos); this.streamPos = cache.getFilePointer(); maxStreamPos = Math.max(maxStreamPos, streamPos); this.bitOffset = 0; } /** * Returns <code>true</code> since this * <code>ImageOutputStream</code> caches data in order to allow * seeking backwards. * * @return <code>true</code>. * * @see #isCachedMemory * @see #isCachedFile */ public boolean isCached() { return true; } /** * Returns <code>true</code> since this * <code>ImageOutputStream</code> maintains a file cache. * * @return <code>true</code>. * * @see #isCached * @see #isCachedMemory */ public boolean isCachedFile() { return true; } /** * Returns <code>false</code> since this * <code>ImageOutputStream</code> does not maintain a main memory * cache. * * @return <code>false</code>. * * @see #isCached * @see #isCachedFile */ public boolean isCachedMemory() { return false; } /** * Closes this <code>FileCacheImageOututStream</code>. All * pending data is flushed to the output, and the cache file * is closed and removed. The destination <code>OutputStream</code> * is not closed. * * @exception IOException if an error occurs. */ public void close() throws IOException { maxStreamPos = cache.length(); seek(maxStreamPos); flushBefore(maxStreamPos); super.close(); cache.close(); cache = null; cacheFile.delete(); cacheFile = null; stream.flush(); stream = null; StreamCloser.removeFromQueue(this); } public void flushBefore(long pos) throws IOException { long oFlushedPos = flushedPos; super.flushBefore(pos); // this will call checkClosed() for us long flushBytes = flushedPos - oFlushedPos; if (flushBytes > 0) { int bufLen = 512; byte[] buf = new byte[bufLen]; cache.seek(oFlushedPos); while (flushBytes > 0) { int len = (int)Math.min(flushBytes, bufLen); cache.readFully(buf, 0, len); stream.write(buf, 0, len); flushBytes -= len; } stream.flush(); } } }