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 | |
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18 | package org.apache.hadoop.io.file.tfile; |
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19 | |
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20 | import java.io.DataInput; |
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21 | import java.io.DataOutput; |
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22 | import java.io.IOException; |
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23 | import java.util.Comparator; |
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24 | import java.util.List; |
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25 | |
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26 | import org.apache.hadoop.io.Text; |
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27 | |
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28 | /** |
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29 | * Supporting Utility classes used by TFile, and shared by users of TFile. |
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30 | */ |
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31 | public final class Utils { |
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32 | |
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33 | /** |
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34 | * Prevent the instantiation of Utils. |
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35 | */ |
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36 | private Utils() { |
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37 | // nothing |
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38 | } |
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39 | |
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40 | /** |
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41 | * Encoding an integer into a variable-length encoding format. Synonymous to |
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42 | * <code>Utils#writeVLong(out, n)</code>. |
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43 | * |
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44 | * @param out |
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45 | * output stream |
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46 | * @param n |
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47 | * The integer to be encoded |
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48 | * @throws IOException |
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49 | * @see Utils#writeVLong(DataOutput, long) |
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50 | */ |
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51 | public static void writeVInt(DataOutput out, int n) throws IOException { |
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52 | writeVLong(out, n); |
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53 | } |
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54 | |
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55 | /** |
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56 | * Encoding a Long integer into a variable-length encoding format. |
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57 | * <ul> |
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58 | * <li>if n in [-32, 127): encode in one byte with the actual value. |
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59 | * Otherwise, |
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60 | * <li>if n in [-20*2^8, 20*2^8): encode in two bytes: byte[0] = n/256 - 52; |
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61 | * byte[1]=n&0xff. Otherwise, |
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62 | * <li>if n IN [-16*2^16, 16*2^16): encode in three bytes: byte[0]=n/2^16 - |
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63 | * 88; byte[1]=(n>>8)&0xff; byte[2]=n&0xff. Otherwise, |
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64 | * <li>if n in [-8*2^24, 8*2^24): encode in four bytes: byte[0]=n/2^24 - 112; |
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65 | * byte[1] = (n>>16)&0xff; byte[2] = (n>>8)&0xff; byte[3]=n&0xff. Otherwise: |
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66 | * <li>if n in [-2^31, 2^31): encode in five bytes: byte[0]=-125; byte[1] = |
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67 | * (n>>24)&0xff; byte[2]=(n>>16)&0xff; byte[3]=(n>>8)&0xff; byte[4]=n&0xff; |
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68 | * <li>if n in [-2^39, 2^39): encode in six bytes: byte[0]=-124; byte[1] = |
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69 | * (n>>32)&0xff; byte[2]=(n>>24)&0xff; byte[3]=(n>>16)&0xff; |
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70 | * byte[4]=(n>>8)&0xff; byte[5]=n&0xff |
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71 | * <li>if n in [-2^47, 2^47): encode in seven bytes: byte[0]=-123; byte[1] = |
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72 | * (n>>40)&0xff; byte[2]=(n>>32)&0xff; byte[3]=(n>>24)&0xff; |
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73 | * byte[4]=(n>>16)&0xff; byte[5]=(n>>8)&0xff; byte[6]=n&0xff; |
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74 | * <li>if n in [-2^55, 2^55): encode in eight bytes: byte[0]=-122; byte[1] = |
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75 | * (n>>48)&0xff; byte[2] = (n>>40)&0xff; byte[3]=(n>>32)&0xff; |
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76 | * byte[4]=(n>>24)&0xff; byte[5]=(n>>16)&0xff; byte[6]=(n>>8)&0xff; |
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77 | * byte[7]=n&0xff; |
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78 | * <li>if n in [-2^63, 2^63): encode in nine bytes: byte[0]=-121; byte[1] = |
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79 | * (n>>54)&0xff; byte[2] = (n>>48)&0xff; byte[3] = (n>>40)&0xff; |
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80 | * byte[4]=(n>>32)&0xff; byte[5]=(n>>24)&0xff; byte[6]=(n>>16)&0xff; |
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81 | * byte[7]=(n>>8)&0xff; byte[8]=n&0xff; |
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82 | * </ul> |
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83 | * |
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84 | * @param out |
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85 | * output stream |
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86 | * @param n |
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87 | * the integer number |
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88 | * @throws IOException |
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89 | */ |
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90 | @SuppressWarnings("fallthrough") |
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91 | public static void writeVLong(DataOutput out, long n) throws IOException { |
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92 | if ((n < 128) && (n >= -32)) { |
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93 | out.writeByte((int) n); |
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94 | return; |
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95 | } |
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96 | |
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97 | long un = (n < 0) ? ~n : n; |
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98 | // how many bytes do we need to represent the number with sign bit? |
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99 | int len = (Long.SIZE - Long.numberOfLeadingZeros(un)) / 8 + 1; |
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100 | int firstByte = (int) (n >> ((len - 1) * 8)); |
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101 | switch (len) { |
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102 | case 1: |
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103 | // fall it through to firstByte==-1, len=2. |
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104 | firstByte >>= 8; |
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105 | case 2: |
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106 | if ((firstByte < 20) && (firstByte >= -20)) { |
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107 | out.writeByte(firstByte - 52); |
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108 | out.writeByte((int) n); |
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109 | return; |
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110 | } |
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111 | // fall it through to firstByte==0/-1, len=3. |
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112 | firstByte >>= 8; |
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113 | case 3: |
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114 | if ((firstByte < 16) && (firstByte >= -16)) { |
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115 | out.writeByte(firstByte - 88); |
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116 | out.writeShort((int) n); |
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117 | return; |
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118 | } |
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119 | // fall it through to firstByte==0/-1, len=4. |
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120 | firstByte >>= 8; |
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121 | case 4: |
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122 | if ((firstByte < 8) && (firstByte >= -8)) { |
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123 | out.writeByte(firstByte - 112); |
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124 | out.writeShort(((int) n) >>> 8); |
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125 | out.writeByte((int) n); |
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126 | return; |
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127 | } |
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128 | out.writeByte(len - 129); |
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129 | out.writeInt((int) n); |
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130 | return; |
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131 | case 5: |
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132 | out.writeByte(len - 129); |
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133 | out.writeInt((int) (n >>> 8)); |
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134 | out.writeByte((int) n); |
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135 | return; |
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136 | case 6: |
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137 | out.writeByte(len - 129); |
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138 | out.writeInt((int) (n >>> 16)); |
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139 | out.writeShort((int) n); |
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140 | return; |
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141 | case 7: |
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142 | out.writeByte(len - 129); |
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143 | out.writeInt((int) (n >>> 24)); |
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144 | out.writeShort((int) (n >>> 8)); |
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145 | out.writeByte((int) n); |
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146 | return; |
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147 | case 8: |
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148 | out.writeByte(len - 129); |
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149 | out.writeLong(n); |
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150 | return; |
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151 | default: |
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152 | throw new RuntimeException("Internel error"); |
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153 | } |
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154 | } |
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155 | |
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156 | /** |
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157 | * Decoding the variable-length integer. Synonymous to |
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158 | * <code>(int)Utils#readVLong(in)</code>. |
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159 | * |
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160 | * @param in |
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161 | * input stream |
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162 | * @return the decoded integer |
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163 | * @throws IOException |
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164 | * |
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165 | * @see Utils#readVLong(DataInput) |
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166 | */ |
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167 | public static int readVInt(DataInput in) throws IOException { |
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168 | long ret = readVLong(in); |
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169 | if ((ret > Integer.MAX_VALUE) || (ret < Integer.MIN_VALUE)) { |
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170 | throw new RuntimeException( |
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171 | "Number too large to be represented as Integer"); |
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172 | } |
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173 | return (int) ret; |
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174 | } |
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175 | |
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176 | /** |
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177 | * Decoding the variable-length integer. Suppose the value of the first byte |
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178 | * is FB, and the following bytes are NB[*]. |
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179 | * <ul> |
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180 | * <li>if (FB >= -32), return (long)FB; |
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181 | * <li>if (FB in [-72, -33]), return (FB+52)<<8 + NB[0]&0xff; |
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182 | * <li>if (FB in [-104, -73]), return (FB+88)<<16 + (NB[0]&0xff)<<8 + |
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183 | * NB[1]&0xff; |
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184 | * <li>if (FB in [-120, -105]), return (FB+112)<<24 + (NB[0]&0xff)<<16 + |
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185 | * (NB[1]&0xff)<<8 + NB[2]&0xff; |
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186 | * <li>if (FB in [-128, -121]), return interpret NB[FB+129] as a signed |
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187 | * big-endian integer. |
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188 | * |
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189 | * @param in |
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190 | * input stream |
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191 | * @return the decoded long integer. |
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192 | * @throws IOException |
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193 | */ |
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194 | |
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195 | public static long readVLong(DataInput in) throws IOException { |
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196 | int firstByte = in.readByte(); |
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197 | if (firstByte >= -32) { |
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198 | return firstByte; |
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199 | } |
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200 | |
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201 | switch ((firstByte + 128) / 8) { |
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202 | case 11: |
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203 | case 10: |
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204 | case 9: |
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205 | case 8: |
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206 | case 7: |
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207 | return ((firstByte + 52) << 8) | in.readUnsignedByte(); |
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208 | case 6: |
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209 | case 5: |
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210 | case 4: |
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211 | case 3: |
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212 | return ((firstByte + 88) << 16) | in.readUnsignedShort(); |
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213 | case 2: |
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214 | case 1: |
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215 | return ((firstByte + 112) << 24) | (in.readUnsignedShort() << 8) |
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216 | | in.readUnsignedByte(); |
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217 | case 0: |
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218 | int len = firstByte + 129; |
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219 | switch (len) { |
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220 | case 4: |
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221 | return in.readInt(); |
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222 | case 5: |
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223 | return ((long) in.readInt()) << 8 | in.readUnsignedByte(); |
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224 | case 6: |
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225 | return ((long) in.readInt()) << 16 | in.readUnsignedShort(); |
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226 | case 7: |
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227 | return ((long) in.readInt()) << 24 | (in.readUnsignedShort() << 8) |
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228 | | in.readUnsignedByte(); |
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229 | case 8: |
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230 | return in.readLong(); |
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231 | default: |
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232 | throw new IOException("Corrupted VLong encoding"); |
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233 | } |
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234 | default: |
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235 | throw new RuntimeException("Internal error"); |
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236 | } |
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237 | } |
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238 | |
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239 | /** |
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240 | * Write a String as a VInt n, followed by n Bytes as in Text format. |
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241 | * |
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242 | * @param out |
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243 | * @param s |
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244 | * @throws IOException |
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245 | */ |
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246 | public static void writeString(DataOutput out, String s) throws IOException { |
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247 | if (s != null) { |
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248 | Text text = new Text(s); |
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249 | byte[] buffer = text.getBytes(); |
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250 | int len = text.getLength(); |
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251 | writeVInt(out, len); |
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252 | out.write(buffer, 0, len); |
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253 | } else { |
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254 | writeVInt(out, -1); |
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255 | } |
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256 | } |
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257 | |
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258 | /** |
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259 | * Read a String as a VInt n, followed by n Bytes in Text format. |
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260 | * |
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261 | * @param in |
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262 | * The input stream. |
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263 | * @return The string |
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264 | * @throws IOException |
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265 | */ |
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266 | public static String readString(DataInput in) throws IOException { |
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267 | int length = readVInt(in); |
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268 | if (length == -1) return null; |
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269 | byte[] buffer = new byte[length]; |
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270 | in.readFully(buffer); |
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271 | return Text.decode(buffer); |
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272 | } |
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273 | |
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274 | /** |
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275 | * A generic Version class. We suggest applications built on top of TFile use |
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276 | * this class to maintain version information in their meta blocks. |
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277 | * |
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278 | * A version number consists of a major version and a minor version. The |
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279 | * suggested usage of major and minor version number is to increment major |
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280 | * version number when the new storage format is not backward compatible, and |
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281 | * increment the minor version otherwise. |
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282 | */ |
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283 | public static final class Version implements Comparable<Version> { |
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284 | private final short major; |
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285 | private final short minor; |
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286 | |
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287 | /** |
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288 | * Construct the Version object by reading from the input stream. |
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289 | * |
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290 | * @param in |
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291 | * input stream |
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292 | * @throws IOException |
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293 | */ |
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294 | public Version(DataInput in) throws IOException { |
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295 | major = in.readShort(); |
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296 | minor = in.readShort(); |
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297 | } |
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298 | |
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299 | /** |
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300 | * Constructor. |
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301 | * |
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302 | * @param major |
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303 | * major version. |
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304 | * @param minor |
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305 | * minor version. |
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306 | */ |
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307 | public Version(short major, short minor) { |
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308 | this.major = major; |
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309 | this.minor = minor; |
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310 | } |
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311 | |
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312 | /** |
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313 | * Write the objec to a DataOutput. The serialized format of the Version is |
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314 | * major version followed by minor version, both as big-endian short |
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315 | * integers. |
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316 | * |
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317 | * @param out |
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318 | * The DataOutput object. |
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319 | * @throws IOException |
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320 | */ |
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321 | public void write(DataOutput out) throws IOException { |
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322 | out.writeShort(major); |
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323 | out.writeShort(minor); |
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324 | } |
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325 | |
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326 | /** |
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327 | * Get the major version. |
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328 | * |
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329 | * @return Major version. |
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330 | */ |
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331 | public int getMajor() { |
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332 | return major; |
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333 | } |
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334 | |
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335 | /** |
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336 | * Get the minor version. |
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337 | * |
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338 | * @return The minor version. |
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339 | */ |
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340 | public int getMinor() { |
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341 | return minor; |
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342 | } |
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343 | |
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344 | /** |
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345 | * Get the size of the serialized Version object. |
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346 | * |
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347 | * @return serialized size of the version object. |
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348 | */ |
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349 | public static int size() { |
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350 | return (Short.SIZE + Short.SIZE) / Byte.SIZE; |
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351 | } |
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352 | |
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353 | /** |
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354 | * Return a string representation of the version. |
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355 | */ |
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356 | public String toString() { |
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357 | return new StringBuilder("v").append(major).append(".").append(minor) |
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358 | .toString(); |
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359 | } |
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360 | |
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361 | /** |
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362 | * Test compatibility. |
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363 | * |
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364 | * @param other |
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365 | * The Version object to test compatibility with. |
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366 | * @return true if both versions have the same major version number; false |
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367 | * otherwise. |
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368 | */ |
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369 | public boolean compatibleWith(Version other) { |
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370 | return major == other.major; |
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371 | } |
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372 | |
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373 | /** |
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374 | * Compare this version with another version. |
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375 | */ |
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376 | @Override |
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377 | public int compareTo(Version that) { |
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378 | if (major != that.major) { |
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379 | return major - that.major; |
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380 | } |
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381 | return minor - that.minor; |
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382 | } |
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383 | |
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384 | @Override |
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385 | public boolean equals(Object other) { |
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386 | if (this == other) return true; |
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387 | if (!(other instanceof Version)) return false; |
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388 | return compareTo((Version) other) == 0; |
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389 | } |
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390 | |
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391 | @Override |
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392 | public int hashCode() { |
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393 | return (major << 16 + minor); |
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394 | } |
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395 | } |
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396 | |
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397 | /** |
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398 | * Lower bound binary search. Find the index to the first element in the list |
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399 | * that compares greater than or equal to key. |
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400 | * |
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401 | * @param <T> |
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402 | * Type of the input key. |
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403 | * @param list |
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404 | * The list |
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405 | * @param key |
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406 | * The input key. |
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407 | * @param cmp |
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408 | * Comparator for the key. |
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409 | * @return The index to the desired element if it exists; or list.size() |
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410 | * otherwise. |
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411 | */ |
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412 | public static <T> int lowerBound(List<? extends T> list, T key, |
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413 | Comparator<? super T> cmp) { |
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414 | int low = 0; |
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415 | int high = list.size(); |
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416 | |
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417 | while (low < high) { |
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418 | int mid = (low + high) >>> 1; |
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419 | T midVal = list.get(mid); |
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420 | int ret = cmp.compare(midVal, key); |
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421 | if (ret < 0) |
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422 | low = mid + 1; |
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423 | else high = mid; |
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424 | } |
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425 | return low; |
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426 | } |
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427 | |
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428 | /** |
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429 | * Upper bound binary search. Find the index to the first element in the list |
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430 | * that compares greater than the input key. |
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431 | * |
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432 | * @param <T> |
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433 | * Type of the input key. |
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434 | * @param list |
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435 | * The list |
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436 | * @param key |
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437 | * The input key. |
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438 | * @param cmp |
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439 | * Comparator for the key. |
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440 | * @return The index to the desired element if it exists; or list.size() |
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441 | * otherwise. |
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442 | */ |
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443 | public static <T> int upperBound(List<? extends T> list, T key, |
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444 | Comparator<? super T> cmp) { |
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445 | int low = 0; |
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446 | int high = list.size(); |
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447 | |
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448 | while (low < high) { |
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449 | int mid = (low + high) >>> 1; |
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450 | T midVal = list.get(mid); |
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451 | int ret = cmp.compare(midVal, key); |
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452 | if (ret <= 0) |
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453 | low = mid + 1; |
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454 | else high = mid; |
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455 | } |
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456 | return low; |
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457 | } |
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458 | |
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459 | /** |
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460 | * Lower bound binary search. Find the index to the first element in the list |
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461 | * that compares greater than or equal to key. |
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462 | * |
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463 | * @param <T> |
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464 | * Type of the input key. |
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465 | * @param list |
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466 | * The list |
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467 | * @param key |
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468 | * The input key. |
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469 | * @return The index to the desired element if it exists; or list.size() |
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470 | * otherwise. |
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471 | */ |
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472 | public static <T> int lowerBound(List<? extends Comparable<? super T>> list, |
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473 | T key) { |
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474 | int low = 0; |
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475 | int high = list.size(); |
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476 | |
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477 | while (low < high) { |
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478 | int mid = (low + high) >>> 1; |
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479 | Comparable<? super T> midVal = list.get(mid); |
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480 | int ret = midVal.compareTo(key); |
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481 | if (ret < 0) |
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482 | low = mid + 1; |
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483 | else high = mid; |
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484 | } |
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485 | return low; |
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486 | } |
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487 | |
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488 | /** |
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489 | * Upper bound binary search. Find the index to the first element in the list |
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490 | * that compares greater than the input key. |
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491 | * |
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492 | * @param <T> |
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493 | * Type of the input key. |
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494 | * @param list |
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495 | * The list |
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496 | * @param key |
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497 | * The input key. |
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498 | * @return The index to the desired element if it exists; or list.size() |
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499 | * otherwise. |
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500 | */ |
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501 | public static <T> int upperBound(List<? extends Comparable<? super T>> list, |
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502 | T key) { |
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503 | int low = 0; |
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504 | int high = list.size(); |
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505 | |
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506 | while (low < high) { |
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507 | int mid = (low + high) >>> 1; |
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508 | Comparable<? super T> midVal = list.get(mid); |
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509 | int ret = midVal.compareTo(key); |
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510 | if (ret <= 0) |
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511 | low = mid + 1; |
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512 | else high = mid; |
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513 | } |
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514 | return low; |
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515 | } |
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516 | } |
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