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/*
* JBoss, Home of Professional Open Source
*
* Copyright 2013 Red Hat, Inc. and/or its affiliates.
*
* Licensed 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.xnio.conduits;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import org.xnio.channels.FixedLengthOverflowException;
import org.xnio.channels.FixedLengthUnderflowException;
import org.xnio.channels.StreamSourceChannel;
import static java.lang.Math.min;
import static org.xnio._private.Messages.msg;
/**
* A stream sink conduit with a limited length.
*
* @author David M. Lloyd
*/
public final class FixedLengthStreamSinkConduit extends AbstractStreamSinkConduit implements StreamSinkConduit {
private long remaining;
/**
* Construct a new instance.
*
* @param next the delegate conduit to set
*/
public FixedLengthStreamSinkConduit(final FixedLengthStreamSinkConduit next) {
super(next);
}
public long transferFrom(final FileChannel src, final long position, final long count) throws IOException {
if (count == 0L) return 0L;
final long remaining = this.remaining;
if (remaining == 0L) {
throw msg.fixedOverflow();
}
long res = 0L;
try {
return res = next.transferFrom(src, position, min(count, remaining));
} finally {
this.remaining = remaining - res;
}
}
public long transferFrom(final StreamSourceChannel source, final long count, final ByteBuffer throughBuffer) throws IOException {
if (count == 0L) return 0L;
final long remaining = this.remaining;
if (remaining == 0L) {
throw msg.fixedOverflow();
}
long res = 0L;
try {
return res = next.transferFrom(source, min(count, remaining), throughBuffer);
} finally {
this.remaining = remaining - res;
}
}
@Override
public int writeFinal(ByteBuffer src) throws IOException {
return write(src, true);
}
@Override
public long writeFinal(ByteBuffer[] srcs, int offset, int length) throws IOException {
return write(srcs, offset, length, true);
}
@Override
public int write(final ByteBuffer src) throws IOException {
return write(src, false);
}
@Override
public long write(final ByteBuffer[] srcs, final int offs, final int len) throws IOException {
return write(srcs, offs, len, false);
}
private int write(final ByteBuffer src, final boolean writeFinal) throws IOException {
if (! src.hasRemaining()) {
return 0;
}
int res = 0;
final long remaining = this.remaining;
if (remaining == 0L) {
throw msg.fixedOverflow();
}
try {
final int lim = src.limit();
final int pos = src.position();
if (lim - pos > remaining) {
src.limit((int) (remaining - (long) pos));
try {
return res = doWrite(src, writeFinal);
} finally {
src.limit(lim);
}
} else {
return res = doWrite(src, writeFinal);
}
} finally {
this.remaining = remaining - res;
}
}
private long write(final ByteBuffer[] srcs, final int offs, final int len, boolean writeFinal) throws IOException {
if (len == 0) {
return 0L;
} else if (len == 1) {
return write(srcs[offs], writeFinal);
}
final long remaining = this.remaining;
if (remaining == 0L) {
throw msg.fixedOverflow();
}
long res = 0L;
try {
int lim;
// The total amount of buffer space discovered so far.
long t = 0L;
for (int i = 0; i < len; i ++) {
final ByteBuffer buffer = srcs[i + offs];
// Grow the discovered buffer space by the remaining size of the current buffer.
// We want to capture the limit so we calculate "remaining" ourselves.
t += (lim = buffer.limit()) - buffer.position();
if (t > remaining) {
// only read up to this point, and trim the last buffer by the number of extra bytes
buffer.limit(lim - (int) (t - (remaining)));
try {
return res = doWrite(srcs, offs, i + 1, writeFinal);
} finally {
// restore the original limit
buffer.limit(lim);
}
}
}
if (t == 0L) {
return 0L;
}
// the total buffer space is less than the remaining count.
return res = doWrite(srcs, offs, len, writeFinal);
} finally {
this.remaining = remaining - res;
}
}
private long doWrite(ByteBuffer[] srcs, int offs, int len, boolean writeFinal) throws IOException {
if(writeFinal) {
return next.writeFinal(srcs, offs, len);
} else {
return next.write(srcs, offs, len);
}
}
private int doWrite(ByteBuffer src, boolean writeFinal) throws IOException {
if(writeFinal) {
return next.writeFinal(src);
} else {
return next.write(src);
}
}
public void terminateWrites() throws IOException {
next.terminateWrites();
if (remaining > 0L) {
throw msg.fixedOverflow();
}
}
public void truncateWrites() throws IOException {
next.terminateWrites();
if (remaining > 0L) {
throw msg.fixedOverflow();
}
}
/**
* Get the number of remaining bytes available to read.
*
* @return the number of remaining bytes available to read
*/
public long getRemaining() {
return remaining;
}
}