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A fork of the Apache Cassandra Project ready to embed Elasticsearch.
/*
* 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.cassandra.io.util;
import java.io.DataInput;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.primitives.Ints;
import org.apache.cassandra.utils.memory.MemoryUtil;
public class MemoryInputStream extends RebufferingInputStream implements DataInput
{
private final Memory mem;
private final int bufferSize;
private long offset;
public MemoryInputStream(Memory mem)
{
this(mem, Ints.saturatedCast(mem.size));
}
@VisibleForTesting
public MemoryInputStream(Memory mem, int bufferSize)
{
super(getByteBuffer(mem.peer, bufferSize));
this.mem = mem;
this.bufferSize = bufferSize;
this.offset = mem.peer + bufferSize;
}
@Override
protected void reBuffer() throws IOException
{
if (offset - mem.peer >= mem.size())
return;
buffer = getByteBuffer(offset, Math.min(bufferSize, Ints.saturatedCast(memRemaining())));
offset += buffer.capacity();
}
@Override
public int available()
{
return Ints.saturatedCast(buffer.remaining() + memRemaining());
}
private long memRemaining()
{
return mem.size + mem.peer - offset;
}
private static ByteBuffer getByteBuffer(long offset, int length)
{
return MemoryUtil.getByteBuffer(offset, length).order(ByteOrder.BIG_ENDIAN);
}
}