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The official Couchbase JVM Core IO Library
/*
* Copyright 2019 Couchbase, Inc.
*
* 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 com.couchbase.client.core.json.stream;
import com.couchbase.client.core.deps.io.netty.buffer.ByteBuf;
import com.couchbase.client.core.deps.io.netty.buffer.ByteBufAllocator;
import static java.nio.charset.StandardCharsets.UTF_8;
/**
* A stream window implementation that copies input data into a single accumulator buffer.
*/
public class CopyingStreamWindow implements StreamWindow {
private final ByteBuf window;
/**
* Offset from the beginning of the stream to the end of the window.
*/
private long streamOffset;
public CopyingStreamWindow(ByteBufAllocator allocator) {
this.window = allocator.buffer();
}
@Override
public void add(ByteBuf buf) {
streamOffset += buf.readableBytes();
try {
window.writeBytes(buf);
} finally {
buf.release();
}
}
@Override
public void releaseBefore(long releaseStreamOffset) {
if (releaseStreamOffset <= 0) {
return;
}
int localOffset = toLocalOffset(releaseStreamOffset);
window.skipBytes(localOffset);
window.discardSomeReadBytes();
}
@Override
public byte[] getBytes(long startStreamOffset, long endStreamOffset) {
final int localStartOffset = toLocalOffset(startStreamOffset);
final int localEndOffset = toLocalOffset(endStreamOffset);
final byte[] result = new byte[localEndOffset - localStartOffset];
window.getBytes(window.readerIndex() + localStartOffset, result);
return result;
}
/**
* @param streamOffset offset from the beginning of the stream
* @return corresponding offset from window's reader index
*/
private int toLocalOffset(long streamOffset) {
return (int) (streamOffset - this.streamOffset + window.readableBytes());
}
@Override
public void close() {
if (window.refCnt() > 0) {
window.release();
}
}
@Override
public String toString() {
return window + ", streamOffset=" + streamOffset + ", content=`" + window.toString(UTF_8) + "`";
}
}