com.twelvemonkeys.imageio.util.IIOInputStreamAdapter Maven / Gradle / Ivy
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.twelvemonkeys.imageio.util;
import com.twelvemonkeys.lang.Validate;
import javax.imageio.stream.ImageInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* IIOInputStreamAdapter
*
* Note: You should always wrap this stream in a {@code BufferedInputStream}.
* If not, performance may degrade significantly.
*
*
* @author Harald Kuhr
* @author last modified by $Author: haraldk$
* @version $Id: IIOInputStreamAdapter.java,v 1.0 Sep 26, 2007 11:35:59 AM haraldk Exp$
*/
class IIOInputStreamAdapter extends InputStream {
private ImageInputStream input;
private final boolean hasLength;
private long left;
private long markPosition;
// TODO: Enforce stream boundaries!
// TODO: Stream start position....
/**
* Creates an {@code InputStream} that reads from the given {@code ImageInputStream}.
* The input stream will read from the current stream position, until the end of the
* underlying stream.
*
* @param pInput the {@code ImageInputStream} to read from.
*/
public IIOInputStreamAdapter(final ImageInputStream pInput) {
this(pInput, -1, false);
}
/**
* Creates an {@code InputStream} that reads from the given {@code ImageInputStream}.
* The input stream will read from the current stream position, until at most
* {@code pLength} bytes has been read.
*
* @param pInput the {@code ImageInputStream} to read from.
* @param pLength the length of the stream
*/
public IIOInputStreamAdapter(final ImageInputStream pInput, final long pLength) {
this(pInput, pLength, true);
}
private IIOInputStreamAdapter(ImageInputStream pInput, long pLength, boolean pHasLength) {
Validate.notNull(pInput, "stream");
Validate.isTrue(!pHasLength || pLength >= 0, pLength, "length < 0: %f");
input = pInput;
left = pLength;
hasLength = pHasLength;
}
/**
* Marks this stream as closed.
* This implementation does not close the underlying stream.
*/
public void close() throws IOException {
if (hasLength) {
input.seek(input.getStreamPosition() + left);
}
left = 0;
input = null;
}
public int available() throws IOException {
if (hasLength) {
return left > 0 ? (int) Math.min(Integer.MAX_VALUE, left) : 0;
}
return 0; // We don't really know, so we say 0 to be safe.
}
@Override
public boolean markSupported() {
return true;
}
public void mark(int pReadLimit) {
try {
markPosition = input.getStreamPosition();
}
catch (IOException e) {
// Let's hope this never happens, because it's not possible to reset then...
throw new IllegalStateException("Could not read stream position: " + e.getMessage(), e);
}
}
public void reset() throws IOException {
long diff = input.getStreamPosition() - markPosition;
input.seek(markPosition);
left += diff;
}
public int read() throws IOException {
if (hasLength && left-- <= 0) {
left = 0;
return -1;
}
return input.read();
}
public final int read(byte[] pBytes) throws IOException {
return read(pBytes, 0, pBytes.length);
}
public int read(final byte[] pBytes, final int pOffset, final int pLength) throws IOException {
if (hasLength && left <= 0) {
return -1;
}
int read = input.read(pBytes, pOffset, (int) findMaxLen(pLength));
if (hasLength) {
left = read < 0 ? 0 : left - read;
}
return read;
}
/**
* Finds the maximum number of bytes we can read or skip, from this stream.
* The number will be in the range {@code [0 ... bytes left]}.
*
* @param pLength the requested length
* @return the maximum number of bytes to read
*/
private long findMaxLen(long pLength) {
if (hasLength && left < pLength) {
return Math.max(left, 0);
}
else {
return Math.max(pLength, 0);
}
}
public long skip(long pLength) throws IOException {
long skipped = input.skipBytes(findMaxLen(pLength)); // Skips 0 or more, never -1
left -= skipped;
return skipped;
}
}