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/*
* 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 org.apache.dubbo.common.io;
import java.io.IOException;
import java.io.InputStream;
/**
* Stream utils.
*/
public class StreamUtils {
private StreamUtils() {
}
public static InputStream limitedInputStream(final InputStream is, final int limit) throws IOException {
return new InputStream() {
private int mPosition = 0;
private int mMark = 0;
private final int mLimit = Math.min(limit, is.available());
@Override
public int read() throws IOException {
if (mPosition < mLimit) {
mPosition++;
return is.read();
}
return -1;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
if (b == null) {
throw new NullPointerException();
}
if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
}
if (mPosition >= mLimit) {
return -1;
}
if (mPosition + len > mLimit) {
len = mLimit - mPosition;
}
if (len <= 0) {
return 0;
}
is.read(b, off, len);
mPosition += len;
return len;
}
@Override
public long skip(long len) throws IOException {
if (mPosition + len > mLimit) {
len = mLimit - mPosition;
}
if (len <= 0) {
return 0;
}
is.skip(len);
mPosition += len;
return len;
}
@Override
public int available() {
return mLimit - mPosition;
}
@Override
public boolean markSupported() {
return is.markSupported();
}
@Override
public void mark(int readlimit) {
is.mark(readlimit);
mMark = mPosition;
}
@Override
public void reset() throws IOException {
is.reset();
mPosition = mMark;
}
@Override
public void close() throws IOException {
is.close();
}
};
}
public static InputStream markSupportedInputStream(final InputStream is, final int markBufferSize) {
if (is.markSupported()) {
return is;
}
return new InputStream() {
byte[] mMarkBuffer;
boolean mInMarked = false;
boolean mInReset = false;
boolean mDry = false;
private int mPosition = 0;
private int mCount = 0;
@Override
public int read() throws IOException {
if (!mInMarked) {
return is.read();
} else {
if (mPosition < mCount) {
byte b = mMarkBuffer[mPosition++];
return b & 0xFF;
}
if (!mInReset) {
if (mDry) {
return -1;
}
if (null == mMarkBuffer) {
mMarkBuffer = new byte[markBufferSize];
}
if (mPosition >= markBufferSize) {
throw new IOException("Mark buffer is full!");
}
int read = is.read();
if (-1 == read) {
mDry = true;
return -1;
}
mMarkBuffer[mPosition++] = (byte) read;
mCount++;
return read;
} else {
// mark buffer is used, exit mark status!
mInMarked = false;
mInReset = false;
mPosition = 0;
mCount = 0;
return is.read();
}
}
}
/**
* NOTE: the readlimit argument for this class
* has no meaning.
*/
@Override
public synchronized void mark(int readlimit) {
mInMarked = true;
mInReset = false;
// mark buffer is not empty
int count = mCount - mPosition;
if (count > 0) {
System.arraycopy(mMarkBuffer, mPosition, mMarkBuffer, 0, count);
mCount = count;
mPosition = 0;
}
}
@Override
public synchronized void reset() throws IOException {
if (!mInMarked) {
throw new IOException("should mark before reset!");
}
mInReset = true;
mPosition = 0;
}
@Override
public boolean markSupported() {
return true;
}
@Override
public int available() throws IOException {
int available = is.available();
if (mInMarked && mInReset) {
available += mCount - mPosition;
}
return available;
}
@Override
public void close() throws IOException {
is.close();
}
};
}
public static InputStream markSupportedInputStream(final InputStream is) {
return markSupportedInputStream(is, 1024);
}
public static void skipUnusedStream(InputStream is) throws IOException {
if (is.available() > 0) {
is.skip(is.available());
}
}
}