| /* |
| * 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.*; |
| import java.nio.ByteBuffer; |
| |
| import org.apache.cassandra.utils.ByteBufferUtil; |
| |
| public class ByteBufferDataInput extends AbstractDataInput implements FileDataInput, DataInput |
| { |
| private final ByteBuffer buffer; |
| private final String filename; |
| private final long segmentOffset; |
| private int position; |
| |
| public ByteBufferDataInput(ByteBuffer buffer, String filename, long segmentOffset, int position) |
| { |
| assert buffer != null; |
| this.buffer = buffer; |
| this.filename = filename; |
| this.segmentOffset = segmentOffset; |
| this.position = position; |
| } |
| |
| // Only use when we know the seek in within the mapped segment. Throws an |
| // IOException otherwise. |
| public void seek(long pos) throws IOException |
| { |
| long inSegmentPos = pos - segmentOffset; |
| if (inSegmentPos < 0 || inSegmentPos > buffer.capacity()) |
| throw new IOException(String.format("Seek position %d is not within mmap segment (seg offs: %d, length: %d)", pos, segmentOffset, buffer.capacity())); |
| |
| position = (int) inSegmentPos; |
| } |
| |
| public long getFilePointer() |
| { |
| return segmentOffset + position; |
| } |
| |
| public long getPosition() |
| { |
| return segmentOffset + position; |
| } |
| |
| public long getPositionLimit() |
| { |
| return segmentOffset + buffer.capacity(); |
| } |
| |
| @Override |
| public boolean markSupported() |
| { |
| return false; |
| } |
| |
| public void reset(FileMark mark) throws IOException |
| { |
| assert mark instanceof MappedFileDataInputMark; |
| position = ((MappedFileDataInputMark) mark).position; |
| } |
| |
| public FileMark mark() |
| { |
| return new MappedFileDataInputMark(position); |
| } |
| |
| public long bytesPastMark(FileMark mark) |
| { |
| assert mark instanceof MappedFileDataInputMark; |
| assert position >= ((MappedFileDataInputMark) mark).position; |
| return position - ((MappedFileDataInputMark) mark).position; |
| } |
| |
| public boolean isEOF() throws IOException |
| { |
| return position == buffer.capacity(); |
| } |
| |
| public long bytesRemaining() throws IOException |
| { |
| return buffer.capacity() - position; |
| } |
| |
| public String getPath() |
| { |
| return filename; |
| } |
| |
| public int read() throws IOException |
| { |
| if (isEOF()) |
| return -1; |
| return buffer.get(position++) & 0xFF; |
| } |
| |
| /** |
| * Does the same thing as <code>readFully</code> do but without copying data (thread safe) |
| * @param length length of the bytes to read |
| * @return buffer with portion of file content |
| * @throws IOException on any fail of I/O operation |
| */ |
| public ByteBuffer readBytes(int length) throws IOException |
| { |
| int remaining = buffer.remaining() - position; |
| if (length > remaining) |
| throw new IOException(String.format("mmap segment underflow; remaining is %d but %d requested", |
| remaining, length)); |
| |
| if (length == 0) |
| return ByteBufferUtil.EMPTY_BYTE_BUFFER; |
| |
| ByteBuffer bytes = buffer.duplicate(); |
| bytes.position(buffer.position() + position).limit(buffer.position() + position + length); |
| position += length; |
| |
| // we have to copy the data in case we unreference the underlying sstable. See CASSANDRA-3179 |
| ByteBuffer clone = ByteBuffer.allocate(bytes.remaining()); |
| clone.put(bytes); |
| clone.flip(); |
| return clone; |
| } |
| |
| @Override |
| public final void readFully(byte[] bytes) throws IOException |
| { |
| ByteBufferUtil.arrayCopy(buffer, buffer.position() + position, bytes, 0, bytes.length); |
| position += bytes.length; |
| } |
| |
| @Override |
| public final void readFully(byte[] bytes, int offset, int count) throws IOException |
| { |
| ByteBufferUtil.arrayCopy(buffer, buffer.position() + position, bytes, offset, count); |
| position += count; |
| } |
| |
| private static class MappedFileDataInputMark implements FileMark |
| { |
| int position; |
| |
| MappedFileDataInputMark(int position) |
| { |
| this.position = position; |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return getClass().getSimpleName() + "(" + |
| "filename='" + filename + "'" + |
| ", position=" + position + |
| ")"; |
| } |
| } |