| /* |
| * 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, ByteOrder.BIG_ENDIAN); |
| } |
| } |