replicant-frameworks_native/awt/javax/imageio/stream/MemoryCacheImageInputStream.java
2009-03-03 19:31:44 -08:00

120 lines
3.1 KiB
Java

/*
* 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 javax.imageio.stream;
import org.apache.harmony.x.imageio.stream.RandomAccessMemoryCache;
import java.io.IOException;
import java.io.InputStream;
/**
* The MemoryCacheImageInputStream class implements ImageInputStream using a
* memory buffer for caching the data.
*
* @since Android 1.0
*/
public class MemoryCacheImageInputStream extends ImageInputStreamImpl {
/**
* The is.
*/
private InputStream is;
/**
* The ramc.
*/
private RandomAccessMemoryCache ramc = new RandomAccessMemoryCache();
/**
* Instantiates a new MemoryCacheImageInputStream which reads from the
* specified InputStream.
*
* @param stream
* the InputStream to be read.
*/
public MemoryCacheImageInputStream(InputStream stream) {
if (stream == null) {
throw new IllegalArgumentException("stream == null!");
}
is = stream;
}
@Override
public int read() throws IOException {
bitOffset = 0;
if (streamPos >= ramc.length()) {
int count = (int)(streamPos - ramc.length() + 1);
int bytesAppended = ramc.appendData(is, count);
if (bytesAppended < count) {
return -1;
}
}
int res = ramc.getData(streamPos);
if (res >= 0) {
streamPos++;
}
return res;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
bitOffset = 0;
if (streamPos >= ramc.length()) {
int count = (int)(streamPos - ramc.length() + len);
ramc.appendData(is, count);
}
int res = ramc.getData(b, off, len, streamPos);
if (res > 0) {
streamPos += res;
}
return res;
}
@Override
public boolean isCached() {
return true;
}
@Override
public boolean isCachedFile() {
return false;
}
@Override
public boolean isCachedMemory() {
return true;
}
@Override
public void close() throws IOException {
super.close();
ramc.close();
}
@Override
public void flushBefore(long pos) throws IOException {
super.flushBefore(pos);
ramc.freeBefore(getFlushedPosition());
}
}