001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019 package org.apache.hadoop.io; 020 021 import java.io.DataInputStream; 022 import java.io.InputStream; 023 import java.nio.ByteBuffer; 024 import java.util.LinkedList; 025 import java.util.List; 026 027 public class DataInputByteBuffer extends DataInputStream { 028 029 private static class Buffer extends InputStream { 030 private final byte[] scratch = new byte[1]; 031 ByteBuffer[] buffers = new ByteBuffer[0]; 032 int bidx, pos, length; 033 @Override 034 public int read() { 035 if (-1 == read(scratch, 0, 1)) { 036 return -1; 037 } 038 return scratch[0] & 0xFF; 039 } 040 @Override 041 public int read(byte[] b, int off, int len) { 042 if (bidx >= buffers.length) { 043 return -1; 044 } 045 int cur = 0; 046 do { 047 int rem = Math.min(len, buffers[bidx].remaining()); 048 buffers[bidx].get(b, off, rem); 049 cur += rem; 050 off += rem; 051 len -= rem; 052 } while (len > 0 && ++bidx < buffers.length); 053 pos += cur; 054 return cur; 055 } 056 public void reset(ByteBuffer[] buffers) { 057 bidx = pos = length = 0; 058 this.buffers = buffers; 059 for (ByteBuffer b : buffers) { 060 length += b.remaining(); 061 } 062 } 063 public int getPosition() { 064 return pos; 065 } 066 public int getLength() { 067 return length; 068 } 069 public ByteBuffer[] getData() { 070 return buffers; 071 } 072 } 073 074 private Buffer buffers; 075 076 public DataInputByteBuffer() { 077 this(new Buffer()); 078 } 079 080 private DataInputByteBuffer(Buffer buffers) { 081 super(buffers); 082 this.buffers = buffers; 083 } 084 085 public void reset(ByteBuffer... input) { 086 buffers.reset(input); 087 } 088 089 public ByteBuffer[] getData() { 090 return buffers.getData(); 091 } 092 093 public int getPosition() { 094 return buffers.getPosition(); 095 } 096 097 public int getLength() { 098 return buffers.getLength(); 099 } 100 }