com.liferay.petra.io.unsync.UnsyncBufferedInputStream Maven / Gradle / Ivy
/**
* Copyright (c) 2000-present Liferay, Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1 of the License, or (at your option)
* any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*/
package com.liferay.petra.io.unsync;
import java.io.IOException;
import java.io.InputStream;
/**
*
* See https://issues.liferay.com/browse/LPS-6648.
*
*
* @author Shuyang Zhou
*/
public class UnsyncBufferedInputStream extends UnsyncFilterInputStream {
public UnsyncBufferedInputStream(InputStream inputStream) {
this(inputStream, _DEFAULT_BUFFER_SIZE);
}
public UnsyncBufferedInputStream(InputStream inputStream, int size) {
super(inputStream);
if (size <= 0) {
throw new IllegalArgumentException("Size is less than 1");
}
_buffer = new byte[size];
}
@Override
public int available() throws IOException {
if (inputStream == null) {
throw new IOException("Input stream is null");
}
return inputStream.available() + (_firstInvalidIndex - _index);
}
@Override
public void close() throws IOException {
if (inputStream != null) {
inputStream.close();
inputStream = null;
_buffer = null;
}
}
@Override
public void mark(int readLimit) {
if (readLimit <= 0) {
return;
}
_markLimitIndex = readLimit;
if (_index == 0) {
return;
}
int available = _firstInvalidIndex - _index;
if (available > 0) {
// Shuffle mark beginning to buffer beginning
System.arraycopy(_buffer, _index, _buffer, 0, available);
_index = 0;
_firstInvalidIndex = available;
}
else {
// Reset buffer states
_index = _firstInvalidIndex = 0;
}
}
@Override
public boolean markSupported() {
return true;
}
@Override
public int read() throws IOException {
if (inputStream == null) {
throw new IOException("Input stream is null");
}
if (_index >= _firstInvalidIndex) {
_fillInBuffer();
if (_index >= _firstInvalidIndex) {
return -1;
}
}
return _buffer[_index++] & 0xff;
}
@Override
public int read(byte[] bytes) throws IOException {
return read(bytes, 0, bytes.length);
}
@Override
public int read(byte[] bytes, int offset, int length) throws IOException {
if (inputStream == null) {
throw new IOException("Input stream is null");
}
if (length < 0) {
throw new IndexOutOfBoundsException("{length=" + length + "}");
}
if (length == 0) {
return 0;
}
int read = 0;
while (true) {
// Try to at least read some data
int currentRead = _readOnce(bytes, offset + read, length - read);
if (currentRead <= 0) {
if (read == 0) {
read = currentRead;
}
break;
}
read += currentRead;
if ((read >= length) || (inputStream.available() <= 0)) {
// Read enough or further reading may be blocked, stop reading
break;
}
}
return read;
}
@Override
public void reset() throws IOException {
if (inputStream == null) {
throw new IOException("Input stream is null");
}
if (_markLimitIndex < 0) {
throw new IOException("Resetting to invalid mark");
}
_index = 0;
}
@Override
public long skip(long skip) throws IOException {
if (inputStream == null) {
throw new IOException("Input stream is null");
}
if (skip <= 0) {
return 0;
}
long available = _firstInvalidIndex - _index;
if (available <= 0) {
if (_markLimitIndex < 0) {
// No mark required, skip the underlying input stream
return inputStream.skip(skip);
}
// Mark required, save the skipped data
_fillInBuffer();
available = _firstInvalidIndex - _index;
if (available <= 0) {
return 0;
}
}
// Skip the data in buffer
if (available < skip) {
skip = available;
}
_index += skip;
return skip;
}
private void _fillInBuffer() throws IOException {
if (_markLimitIndex < 0) {
// No mark required, fill the buffer
_index = _firstInvalidIndex = 0;
int number = inputStream.read(_buffer);
if (number > 0) {
_firstInvalidIndex = number;
}
return;
}
// Mark required
if (_index >= _markLimitIndex) {
// Passed mark limit indexs, get rid of all cache data
_markLimitIndex = -1;
_index = _firstInvalidIndex = 0;
}
else if (_index == _buffer.length) {
// Cannot get rid of cache data and there is no room to read in any
// more data, so grow the buffer
int newBufferSize = _buffer.length * 2;
if (newBufferSize > _markLimitIndex) {
newBufferSize = _markLimitIndex;
}
byte[] newBuffer = new byte[newBufferSize];
System.arraycopy(_buffer, 0, newBuffer, 0, _buffer.length);
_buffer = newBuffer;
}
// Read underlying input stream since the buffer has more space
_firstInvalidIndex = _index;
int number = inputStream.read(_buffer, _index, _buffer.length - _index);
if (number > 0) {
_firstInvalidIndex += number;
}
}
private int _readOnce(byte[] bytes, int offset, int length)
throws IOException {
int available = _firstInvalidIndex - _index;
if (available <= 0) {
// Buffer is empty, read from under input stream
if ((_markLimitIndex < 0) && (length >= _buffer.length)) {
// No mark required, left read block is no less than buffer,
// read through buffer is inefficient, so directly read from
// underlying input stream
return inputStream.read(bytes, offset, length);
}
// Mark is required, has to read through the buffer to remember
// data
_fillInBuffer();
available = _firstInvalidIndex - _index;
if (available <= 0) {
return -1;
}
}
if (length > available) {
length = available;
}
System.arraycopy(_buffer, _index, bytes, offset, length);
_index += length;
return length;
}
private static final int _DEFAULT_BUFFER_SIZE = 8192;
private byte[] _buffer;
private int _firstInvalidIndex;
private int _index;
private int _markLimitIndex = -1;
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