org.glassfish.grizzly.utils.BufferInputStream Maven / Gradle / Ivy
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package org.glassfish.grizzly.utils;
import java.io.IOException;
import java.io.InputStream;
import org.glassfish.grizzly.Buffer;
import org.glassfish.grizzly.memory.Buffers;
/**
* {@link InputStream} implementation over Grizzly {@link Buffer}.
*
* @author Alexey Stashok
*/
public class BufferInputStream extends InputStream {
private final Buffer buffer;
private final boolean isMovingPosition;
private int position;
private final int limit;
/**
* Create the {@link InputStream} over Grizzly {@link Buffer}.
* Constructed BufferInputStream read operations will affect the
* passed {@link Buffer} position, which means each BufferInputStream
* read operation will shift {@link Buffer}'s position by number of bytes,
* which were read.
*
* @param buffer
*/
public BufferInputStream(final Buffer buffer) {
isMovingPosition = true;
this.buffer = buffer;
this.position = buffer.position();
this.limit = buffer.limit();
}
/**
* Create the {@link InputStream} over Grizzly {@link Buffer}.
* Constructed BufferInputStream read operations will *not* affect
* the passed {@link Buffer} position, which means the passed {@link Buffer}
* position will never be changed during BufferInputStream
*
* @param buffer
*/
public BufferInputStream(final Buffer buffer, final int position,
final int limit) {
isMovingPosition = false;
this.buffer = buffer;
this.position = position;
this.limit = limit;
}
/**
* {@inheritDoc}
*/
@Override
public int read() throws IOException {
if (position >= limit) {
return -1;
}
final int result = buffer.get(position++) & 0xFF;
if (isMovingPosition) {
buffer.position(position);
}
return result;
}
/**
* {@inheritDoc}
*/
@Override
public int read(final byte[] b, final int off, final int len)
throws IOException {
if (position >= limit) {
return -1;
}
final int length = Math.min(len, available());
final int oldPos = buffer.position();
final int oldLim = buffer.limit();
if (!isMovingPosition) {
Buffers.setPositionLimit(buffer, position, limit);
}
try {
buffer.get(b, off, length);
} finally {
if (!isMovingPosition) {
Buffers.setPositionLimit(buffer, oldPos, oldLim);
}
}
position += length;
return length;
}
/**
* {@inheritDoc}
*/
@Override
public int available() throws IOException {
return limit - position;
}
/**
* {@inheritDoc}
*/
@Override
public long skip(final long n) throws IOException {
final int skipped = (int) Math.min(n, available());
position += skipped;
if (isMovingPosition) {
buffer.position(position);
}
return skipped;
}
}