114 lines
3.0 KiB
Java
114 lines
3.0 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package javax.imageio.stream;
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import org.apache.harmony.x.imageio.stream.RandomAccessMemoryCache;
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import java.io.IOException;
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import java.io.InputStream;
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/**
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* The MemoryCacheImageInputStream class implements ImageInputStream
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* using a memory buffer for caching the data.
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*/
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public class MemoryCacheImageInputStream extends ImageInputStreamImpl {
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/** The is. */
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private InputStream is;
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/** The ramc. */
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private RandomAccessMemoryCache ramc = new RandomAccessMemoryCache();
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/**
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* Instantiates a new MemoryCacheImageInputStream
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* which reads from the specified InputStream.
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*
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* @param stream the InputStream to be read.
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*/
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public MemoryCacheImageInputStream(InputStream stream) {
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if (stream == null) {
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throw new IllegalArgumentException("stream == null!");
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}
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is = stream;
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}
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@Override
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public int read() throws IOException {
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bitOffset = 0;
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if (streamPos >= ramc.length()) {
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int count = (int)(streamPos - ramc.length() + 1);
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int bytesAppended = ramc.appendData(is, count);
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if (bytesAppended < count) {
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return -1;
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}
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}
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int res = ramc.getData(streamPos);
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if (res >= 0) {
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streamPos++;
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}
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return res;
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}
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@Override
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public int read(byte[] b, int off, int len) throws IOException {
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bitOffset = 0;
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if (streamPos >= ramc.length()) {
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int count = (int)(streamPos - ramc.length() + len);
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ramc.appendData(is, count);
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}
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int res = ramc.getData(b, off, len, streamPos);
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if (res > 0) {
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streamPos += res;
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}
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return res;
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}
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@Override
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public boolean isCached() {
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return true;
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}
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@Override
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public boolean isCachedFile() {
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return false;
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}
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@Override
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public boolean isCachedMemory() {
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return true;
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}
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@Override
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public void close() throws IOException {
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super.close();
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ramc.close();
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}
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@Override
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public void flushBefore(long pos) throws IOException {
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super.flushBefore(pos);
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ramc.freeBefore(getFlushedPosition());
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}
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}
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