[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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| 3 | * contributor license agreements. See the NOTICE file distributed with this |
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| 4 | * work for additional information regarding copyright ownership. The ASF |
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| 5 | * licenses this file to you under the Apache License, Version 2.0 (the |
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| 6 | * "License"); you may not use this file except in compliance with the License. |
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| 7 | * You may obtain a copy of the License at |
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| 8 | * |
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| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 10 | * |
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| 11 | * Unless required by applicable law or agreed to in writing, software |
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| 12 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
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| 13 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
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| 14 | * License for the specific language governing permissions and limitations under |
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| 15 | * the License. |
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| 16 | */ |
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| 17 | package org.apache.hadoop.io.file.tfile; |
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| 18 | |
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| 19 | import java.io.DataInputStream; |
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| 20 | import java.io.DataOutputStream; |
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| 21 | import java.io.IOException; |
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| 22 | import java.io.InputStream; |
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| 23 | import java.io.OutputStream; |
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| 24 | |
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| 25 | /** |
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| 26 | * Several related classes to support chunk-encoded sub-streams on top of a |
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| 27 | * regular stream. |
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| 28 | */ |
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| 29 | final class Chunk { |
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| 30 | |
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| 31 | /** |
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| 32 | * Prevent the instantiation of class. |
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| 33 | */ |
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| 34 | private Chunk() { |
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| 35 | // nothing |
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| 36 | } |
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| 37 | |
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| 38 | /** |
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| 39 | * Decoding a chain of chunks encoded through ChunkEncoder or |
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| 40 | * SingleChunkEncoder. |
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| 41 | */ |
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| 42 | static public class ChunkDecoder extends InputStream { |
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| 43 | private DataInputStream in = null; |
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| 44 | private boolean lastChunk; |
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| 45 | private int remain = 0; |
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| 46 | private boolean closed; |
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| 47 | |
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| 48 | public ChunkDecoder() { |
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| 49 | lastChunk = true; |
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| 50 | closed = true; |
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| 51 | } |
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| 52 | |
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| 53 | public void reset(DataInputStream downStream) { |
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| 54 | // no need to wind forward the old input. |
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| 55 | in = downStream; |
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| 56 | lastChunk = false; |
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| 57 | remain = 0; |
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| 58 | closed = false; |
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| 59 | } |
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| 60 | |
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| 61 | /** |
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| 62 | * Constructor |
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| 63 | * |
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| 64 | * @param in |
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| 65 | * The source input stream which contains chunk-encoded data |
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| 66 | * stream. |
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| 67 | */ |
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| 68 | public ChunkDecoder(DataInputStream in) { |
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| 69 | this.in = in; |
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| 70 | lastChunk = false; |
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| 71 | closed = false; |
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| 72 | } |
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| 73 | |
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| 74 | /** |
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| 75 | * Have we reached the last chunk. |
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| 76 | * |
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| 77 | * @return true if we have reached the last chunk. |
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| 78 | * @throws java.io.IOException |
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| 79 | */ |
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| 80 | public boolean isLastChunk() throws IOException { |
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| 81 | checkEOF(); |
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| 82 | return lastChunk; |
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| 83 | } |
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| 84 | |
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| 85 | /** |
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| 86 | * How many bytes remain in the current chunk? |
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| 87 | * |
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| 88 | * @return remaining bytes left in the current chunk. |
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| 89 | * @throws java.io.IOException |
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| 90 | */ |
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| 91 | public int getRemain() throws IOException { |
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| 92 | checkEOF(); |
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| 93 | return remain; |
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| 94 | } |
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| 95 | |
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| 96 | /** |
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| 97 | * Reading the length of next chunk. |
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| 98 | * |
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| 99 | * @throws java.io.IOException |
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| 100 | * when no more data is available. |
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| 101 | */ |
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| 102 | private void readLength() throws IOException { |
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| 103 | remain = Utils.readVInt(in); |
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| 104 | if (remain >= 0) { |
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| 105 | lastChunk = true; |
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| 106 | } else { |
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| 107 | remain = -remain; |
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| 108 | } |
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| 109 | } |
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| 110 | |
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| 111 | /** |
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| 112 | * Check whether we reach the end of the stream. |
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| 113 | * |
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| 114 | * @return false if the chunk encoded stream has more data to read (in which |
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| 115 | * case available() will be greater than 0); true otherwise. |
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| 116 | * @throws java.io.IOException |
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| 117 | * on I/O errors. |
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| 118 | */ |
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| 119 | private boolean checkEOF() throws IOException { |
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| 120 | if (isClosed()) return true; |
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| 121 | while (true) { |
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| 122 | if (remain > 0) return false; |
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| 123 | if (lastChunk) return true; |
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| 124 | readLength(); |
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| 125 | } |
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| 126 | } |
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| 127 | |
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| 128 | @Override |
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| 129 | /* |
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| 130 | * This method never blocks the caller. Returning 0 does not mean we reach |
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| 131 | * the end of the stream. |
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| 132 | */ |
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| 133 | public int available() { |
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| 134 | return remain; |
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| 135 | } |
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| 136 | |
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| 137 | @Override |
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| 138 | public int read() throws IOException { |
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| 139 | if (checkEOF()) return -1; |
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| 140 | int ret = in.read(); |
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| 141 | if (ret < 0) throw new IOException("Corrupted chunk encoding stream"); |
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| 142 | --remain; |
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| 143 | return ret; |
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| 144 | } |
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| 145 | |
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| 146 | @Override |
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| 147 | public int read(byte[] b) throws IOException { |
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| 148 | return read(b, 0, b.length); |
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| 149 | } |
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| 150 | |
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| 151 | @Override |
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| 152 | public int read(byte[] b, int off, int len) throws IOException { |
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| 153 | if ((off | len | (off + len) | (b.length - (off + len))) < 0) { |
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| 154 | throw new IndexOutOfBoundsException(); |
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| 155 | } |
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| 156 | |
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| 157 | if (!checkEOF()) { |
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| 158 | int n = Math.min(remain, len); |
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| 159 | int ret = in.read(b, off, n); |
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| 160 | if (ret < 0) throw new IOException("Corrupted chunk encoding stream"); |
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| 161 | remain -= ret; |
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| 162 | return ret; |
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| 163 | } |
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| 164 | return -1; |
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| 165 | } |
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| 166 | |
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| 167 | @Override |
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| 168 | public long skip(long n) throws IOException { |
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| 169 | if (!checkEOF()) { |
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| 170 | long ret = in.skip(Math.min(remain, n)); |
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| 171 | remain -= ret; |
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| 172 | return ret; |
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| 173 | } |
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| 174 | return 0; |
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| 175 | } |
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| 176 | |
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| 177 | @Override |
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| 178 | public boolean markSupported() { |
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| 179 | return false; |
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| 180 | } |
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| 181 | |
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| 182 | public boolean isClosed() { |
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| 183 | return closed; |
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| 184 | } |
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| 185 | |
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| 186 | @Override |
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| 187 | public void close() throws IOException { |
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| 188 | if (closed == false) { |
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| 189 | try { |
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| 190 | while (!checkEOF()) { |
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| 191 | skip(Integer.MAX_VALUE); |
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| 192 | } |
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| 193 | } finally { |
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| 194 | closed = true; |
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| 195 | } |
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| 196 | } |
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| 197 | } |
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| 198 | } |
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| 199 | |
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| 200 | /** |
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| 201 | * Chunk Encoder. Encoding the output data into a chain of chunks in the |
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| 202 | * following sequences: -len1, byte[len1], -len2, byte[len2], ... len_n, |
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| 203 | * byte[len_n]. Where len1, len2, ..., len_n are the lengths of the data |
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| 204 | * chunks. Non-terminal chunks have their lengths negated. Non-terminal chunks |
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| 205 | * cannot have length 0. All lengths are in the range of 0 to |
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| 206 | * Integer.MAX_VALUE and are encoded in Utils.VInt format. |
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| 207 | */ |
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| 208 | static public class ChunkEncoder extends OutputStream { |
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| 209 | /** |
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| 210 | * The data output stream it connects to. |
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| 211 | */ |
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| 212 | private DataOutputStream out; |
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| 213 | |
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| 214 | /** |
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| 215 | * The internal buffer that is only used when we do not know the advertised |
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| 216 | * size. |
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| 217 | */ |
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| 218 | private byte buf[]; |
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| 219 | |
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| 220 | /** |
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| 221 | * The number of valid bytes in the buffer. This value is always in the |
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| 222 | * range <tt>0</tt> through <tt>buf.length</tt>; elements <tt>buf[0]</tt> |
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| 223 | * through <tt>buf[count-1]</tt> contain valid byte data. |
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| 224 | */ |
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| 225 | private int count; |
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| 226 | |
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| 227 | /** |
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| 228 | * Constructor. |
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| 229 | * |
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| 230 | * @param out |
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| 231 | * the underlying output stream. |
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| 232 | * @param buf |
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| 233 | * user-supplied buffer. The buffer would be used exclusively by |
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| 234 | * the ChunkEncoder during its life cycle. |
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| 235 | */ |
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| 236 | public ChunkEncoder(DataOutputStream out, byte[] buf) { |
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| 237 | this.out = out; |
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| 238 | this.buf = buf; |
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| 239 | this.count = 0; |
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| 240 | } |
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| 241 | |
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| 242 | /** |
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| 243 | * Write out a chunk. |
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| 244 | * |
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| 245 | * @param chunk |
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| 246 | * The chunk buffer. |
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| 247 | * @param offset |
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| 248 | * Offset to chunk buffer for the beginning of chunk. |
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| 249 | * @param len |
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| 250 | * @param last |
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| 251 | * Is this the last call to flushBuffer? |
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| 252 | */ |
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| 253 | private void writeChunk(byte[] chunk, int offset, int len, boolean last) |
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| 254 | throws IOException { |
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| 255 | if (last) { // always write out the length for the last chunk. |
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| 256 | Utils.writeVInt(out, len); |
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| 257 | if (len > 0) { |
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| 258 | out.write(chunk, offset, len); |
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| 259 | } |
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| 260 | } else { |
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| 261 | if (len > 0) { |
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| 262 | Utils.writeVInt(out, -len); |
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| 263 | out.write(chunk, offset, len); |
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| 264 | } |
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| 265 | } |
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| 266 | } |
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| 267 | |
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| 268 | /** |
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| 269 | * Write out a chunk that is a concatenation of the internal buffer plus |
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| 270 | * user supplied data. This will never be the last block. |
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| 271 | * |
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| 272 | * @param data |
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| 273 | * User supplied data buffer. |
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| 274 | * @param offset |
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| 275 | * Offset to user data buffer. |
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| 276 | * @param len |
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| 277 | * User data buffer size. |
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| 278 | */ |
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| 279 | private void writeBufData(byte[] data, int offset, int len) |
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| 280 | throws IOException { |
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| 281 | if (count + len > 0) { |
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| 282 | Utils.writeVInt(out, -(count + len)); |
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| 283 | out.write(buf, 0, count); |
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| 284 | count = 0; |
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| 285 | out.write(data, offset, len); |
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| 286 | } |
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| 287 | } |
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| 288 | |
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| 289 | /** |
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| 290 | * Flush the internal buffer. |
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| 291 | * |
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| 292 | * Is this the last call to flushBuffer? |
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| 293 | * |
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| 294 | * @throws java.io.IOException |
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| 295 | */ |
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| 296 | private void flushBuffer() throws IOException { |
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| 297 | if (count > 0) { |
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| 298 | writeChunk(buf, 0, count, false); |
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| 299 | count = 0; |
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| 300 | } |
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| 301 | } |
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| 302 | |
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| 303 | @Override |
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| 304 | public void write(int b) throws IOException { |
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| 305 | if (count >= buf.length) { |
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| 306 | flushBuffer(); |
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| 307 | } |
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| 308 | buf[count++] = (byte) b; |
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| 309 | } |
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| 310 | |
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| 311 | @Override |
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| 312 | public void write(byte b[]) throws IOException { |
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| 313 | write(b, 0, b.length); |
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| 314 | } |
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| 315 | |
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| 316 | @Override |
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| 317 | public void write(byte b[], int off, int len) throws IOException { |
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| 318 | if ((len + count) >= buf.length) { |
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| 319 | /* |
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| 320 | * If the input data do not fit in buffer, flush the output buffer and |
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| 321 | * then write the data directly. In this way buffered streams will |
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| 322 | * cascade harmlessly. |
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| 323 | */ |
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| 324 | writeBufData(b, off, len); |
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| 325 | return; |
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| 326 | } |
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| 327 | |
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| 328 | System.arraycopy(b, off, buf, count, len); |
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| 329 | count += len; |
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| 330 | } |
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| 331 | |
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| 332 | @Override |
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| 333 | public void flush() throws IOException { |
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| 334 | flushBuffer(); |
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| 335 | out.flush(); |
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| 336 | } |
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| 337 | |
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| 338 | @Override |
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| 339 | public void close() throws IOException { |
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| 340 | if (buf != null) { |
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| 341 | try { |
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| 342 | writeChunk(buf, 0, count, true); |
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| 343 | } finally { |
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| 344 | buf = null; |
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| 345 | out = null; |
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| 346 | } |
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| 347 | } |
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| 348 | } |
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| 349 | } |
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| 350 | |
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| 351 | /** |
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| 352 | * Encode the whole stream as a single chunk. Expecting to know the size of |
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| 353 | * the chunk up-front. |
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| 354 | */ |
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| 355 | static public class SingleChunkEncoder extends OutputStream { |
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| 356 | /** |
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| 357 | * The data output stream it connects to. |
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| 358 | */ |
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| 359 | private final DataOutputStream out; |
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| 360 | |
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| 361 | /** |
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| 362 | * The remaining bytes to be written. |
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| 363 | */ |
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| 364 | private int remain; |
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| 365 | private boolean closed = false; |
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| 366 | |
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| 367 | /** |
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| 368 | * Constructor. |
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| 369 | * |
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| 370 | * @param out |
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| 371 | * the underlying output stream. |
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| 372 | * @param size |
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| 373 | * The total # of bytes to be written as a single chunk. |
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| 374 | * @throws java.io.IOException |
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| 375 | * if an I/O error occurs. |
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| 376 | */ |
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| 377 | public SingleChunkEncoder(DataOutputStream out, int size) |
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| 378 | throws IOException { |
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| 379 | this.out = out; |
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| 380 | this.remain = size; |
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| 381 | Utils.writeVInt(out, size); |
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| 382 | } |
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| 383 | |
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| 384 | @Override |
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| 385 | public void write(int b) throws IOException { |
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| 386 | if (remain > 0) { |
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| 387 | out.write(b); |
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| 388 | --remain; |
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| 389 | } else { |
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| 390 | throw new IOException("Writing more bytes than advertised size."); |
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| 391 | } |
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| 392 | } |
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| 393 | |
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| 394 | @Override |
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| 395 | public void write(byte b[]) throws IOException { |
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| 396 | write(b, 0, b.length); |
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| 397 | } |
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| 398 | |
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| 399 | @Override |
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| 400 | public void write(byte b[], int off, int len) throws IOException { |
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| 401 | if (remain >= len) { |
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| 402 | out.write(b, off, len); |
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| 403 | remain -= len; |
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| 404 | } else { |
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| 405 | throw new IOException("Writing more bytes than advertised size."); |
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| 406 | } |
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| 407 | } |
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| 408 | |
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| 409 | @Override |
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| 410 | public void flush() throws IOException { |
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| 411 | out.flush(); |
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| 412 | } |
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| 413 | |
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| 414 | @Override |
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| 415 | public void close() throws IOException { |
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| 416 | if (closed == true) { |
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| 417 | return; |
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| 418 | } |
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| 419 | |
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| 420 | try { |
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| 421 | if (remain > 0) { |
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| 422 | throw new IOException("Writing less bytes than advertised size."); |
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| 423 | } |
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| 424 | } finally { |
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| 425 | closed = true; |
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| 426 | } |
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| 427 | } |
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| 428 | } |
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| 429 | } |
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