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| 1 | /* | ||
| 2 | * Copyright (c) 2000, 2006, 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 javax.imageio.stream; | ||
| 27 | |||
| 28 | import java.io.IOException; | ||
| 29 | import java.io.OutputStream; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * An implementation of <code>ImageOutputStream</code> that writes its | ||
| 33 | * output to a regular <code>OutputStream</code>. A memory buffer is | ||
| 34 | * used to cache at least the data between the discard position and | ||
| 35 | * the current write position. The only constructor takes an | ||
| 36 | * <code>OutputStream</code>, so this class may not be used for | ||
| 37 | * read/modify/write operations. Reading can occur only on parts of | ||
| 38 | * the stream that have already been written to the cache and not | ||
| 39 | * yet flushed. | ||
| 40 | * | ||
| 41 | */ | ||
| 42 | public class MemoryCacheImageOutputStream extends ImageOutputStreamImpl { | ||
| 43 | |||
| 44 | private OutputStream stream; | ||
| 45 | |||
| 46 | private MemoryCache cache = new MemoryCache(); | ||
| 47 | |||
| 48 | /** | ||
| 49 | * Constructs a <code>MemoryCacheImageOutputStream</code> that will write | ||
| 50 | * to a given <code>OutputStream</code>. | ||
| 51 | * | ||
| 52 | * @param stream an <code>OutputStream</code> to write to. | ||
| 53 | * | ||
| 54 | * @exception IllegalArgumentException if <code>stream</code> is | ||
| 55 | * <code>null</code>. | ||
| 56 | */ | ||
| 57 | public MemoryCacheImageOutputStream(OutputStream stream) { | ||
| 58 | if (stream == null) { | ||
| 59 | throw new IllegalArgumentException("stream == null!"); | ||
| 60 | } | ||
| 61 | this.stream = stream; | ||
| 62 | } | ||
| 63 | |||
| 64 | public int read() throws IOException { | ||
| 65 | checkClosed(); | ||
| 66 | |||
| 67 | bitOffset = 0; | ||
| 68 | |||
| 69 | int val = cache.read(streamPos); | ||
| 70 | if (val != -1) { | ||
| 71 | ++streamPos; | ||
| 72 | } | ||
| 73 | return val; | ||
| 74 | } | ||
| 75 | |||
| 76 | public int read(byte[] b, int off, int len) throws IOException { | ||
| 77 | checkClosed(); | ||
| 78 | |||
| 79 | if (b == null) { | ||
| 80 | throw new NullPointerException("b == null!"); | ||
| 81 | } | ||
| 82 | // Fix 4467608: read([B,I,I) works incorrectly if len<=0 | ||
| 83 | if (off < 0 || len < 0 || off + len > b.length || off + len < 0) { | ||
| 84 | throw new IndexOutOfBoundsException | ||
| 85 | ("off < 0 || len < 0 || off+len > b.length || off+len < 0!"); | ||
| 86 | } | ||
| 87 | |||
| 88 | bitOffset = 0; | ||
| 89 | |||
| 90 | if (len == 0) { | ||
| 91 | return 0; | ||
| 92 | } | ||
| 93 | |||
| 94 | // check if we're already at/past EOF i.e. | ||
| 95 | // no more bytes left to read from cache | ||
| 96 | long bytesLeftInCache = cache.getLength() - streamPos; | ||
| 97 | if (bytesLeftInCache <= 0) { | ||
| 98 | return -1; // EOF | ||
| 99 | } | ||
| 100 | |||
| 101 | // guaranteed by now that bytesLeftInCache > 0 && len > 0 | ||
| 102 | // and so the rest of the error checking is done by cache.read() | ||
| 103 | // NOTE that alot of error checking is duplicated | ||
| 104 | len = (int)Math.min(bytesLeftInCache, (long)len); | ||
| 105 | cache.read(b, off, len, streamPos); | ||
| 106 | streamPos += len; | ||
| 107 | return len; | ||
| 108 | } | ||
| 109 | |||
| 110 | public void write(int b) throws IOException { | ||
| 111 | flushBits(); // this will call checkClosed() for us | ||
| 112 | cache.write(b, streamPos); | ||
| 113 | ++streamPos; | ||
| 114 | } | ||
| 115 | |||
| 116 | public void write(byte[] b, int off, int len) throws IOException { | ||
| 117 | flushBits(); // this will call checkClosed() for us | ||
| 118 | cache.write(b, off, len, streamPos); | ||
| 119 | streamPos += len; | ||
| 120 | } | ||
| 121 | |||
| 122 | public long length() { | ||
| 123 | try { | ||
| 124 | checkClosed(); | ||
| 125 | return cache.getLength(); | ||
| 126 | } catch (IOException e) { | ||
| 127 | return -1L; | ||
| 128 | } | ||
| 129 | } | ||
| 130 | |||
| 131 | /** | ||
| 132 | * Returns <code>true</code> since this | ||
| 133 | * <code>ImageOutputStream</code> caches data in order to allow | ||
| 134 | * seeking backwards. | ||
| 135 | * | ||
| 136 | * @return <code>true</code>. | ||
| 137 | * | ||
| 138 | * @see #isCachedMemory | ||
| 139 | * @see #isCachedFile | ||
| 140 | */ | ||
| 141 | public boolean isCached() { | ||
| 142 | return true; | ||
| 143 | } | ||
| 144 | |||
| 145 | /** | ||
| 146 | * Returns <code>false</code> since this | ||
| 147 | * <code>ImageOutputStream</code> does not maintain a file cache. | ||
| 148 | * | ||
| 149 | * @return <code>false</code>. | ||
| 150 | * | ||
| 151 | * @see #isCached | ||
| 152 | * @see #isCachedMemory | ||
| 153 | */ | ||
| 154 | public boolean isCachedFile() { | ||
| 155 | return false; | ||
| 156 | } | ||
| 157 | |||
| 158 | /** | ||
| 159 | * Returns <code>true</code> since this | ||
| 160 | * <code>ImageOutputStream</code> maintains a main memory cache. | ||
| 161 | * | ||
| 162 | * @return <code>true</code>. | ||
| 163 | * | ||
| 164 | * @see #isCached | ||
| 165 | * @see #isCachedFile | ||
| 166 | */ | ||
| 167 | public boolean isCachedMemory() { | ||
| 168 | return true; | ||
| 169 | } | ||
| 170 | |||
| 171 | /** | ||
| 172 | * Closes this <code>MemoryCacheImageOutputStream</code>. All | ||
| 173 | * pending data is flushed to the output, and the cache | ||
| 174 | * is released. The destination <code>OutputStream</code> | ||
| 175 | * is not closed. | ||
| 176 | */ | ||
| 177 | public void close() throws IOException { | ||
| 178 | long length = cache.getLength(); | ||
| 179 | seek(length); | ||
| 180 | flushBefore(length); | ||
| 181 | super.close(); | ||
| 182 | cache.reset(); | ||
| 183 | cache = null; | ||
| 184 | stream = null; | ||
| 185 | } | ||
| 186 | |||
| 187 | public void flushBefore(long pos) throws IOException { | ||
| 188 | long oFlushedPos = flushedPos; | ||
| 189 | super.flushBefore(pos); // this will call checkClosed() for us | ||
| 190 | |||
| 191 | long flushBytes = flushedPos - oFlushedPos; | ||
| 192 | cache.writeToStream(stream, oFlushedPos, flushBytes); | ||
| 193 | cache.disposeBefore(flushedPos); | ||
| 194 | stream.flush(); | ||
| 195 | } | ||
| 196 | } | ||