1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one |
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3 | * or more contributor license agreements. See the NOTICE file |
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4 | * distributed with this work for additional information |
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5 | * regarding copyright ownership. The ASF licenses this file |
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6 | * to you under the Apache License, Version 2.0 (the |
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7 | * "License"); you may not use this file except in compliance |
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8 | * with the License. You may obtain a copy of the License at |
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9 | * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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11 | * |
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12 | * Unless required by applicable law or agreed to in writing, software |
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13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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15 | * See the License for the specific language governing permissions and |
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16 | * limitations under the License. |
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17 | */ |
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18 | |
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19 | package org.apache.hadoop.util; |
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20 | |
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21 | public class UTF8ByteArrayUtils { |
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22 | /** |
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23 | * Find the first occurrence of the given byte b in a UTF-8 encoded string |
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24 | * @param utf a byte array containing a UTF-8 encoded string |
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25 | * @param start starting offset |
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26 | * @param end ending position |
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27 | * @param b the byte to find |
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28 | * @return position that first byte occures otherwise -1 |
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29 | */ |
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30 | public static int findByte(byte [] utf, int start, int end, byte b) { |
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31 | for(int i=start; i<end; i++) { |
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32 | if (utf[i]==b) { |
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33 | return i; |
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34 | } |
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35 | } |
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36 | return -1; |
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37 | } |
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38 | |
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39 | /** |
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40 | * Find the first occurrence of the given bytes b in a UTF-8 encoded string |
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41 | * @param utf a byte array containing a UTF-8 encoded string |
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42 | * @param start starting offset |
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43 | * @param end ending position |
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44 | * @param b the bytes to find |
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45 | * @return position that first byte occures otherwise -1 |
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46 | */ |
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47 | public static int findBytes(byte [] utf, int start, int end, byte[] b) { |
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48 | int matchEnd = end - b.length; |
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49 | for(int i=start; i<=matchEnd; i++) { |
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50 | boolean matched = true; |
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51 | for(int j=0; j<b.length; j++) { |
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52 | if (utf[i+j] != b[j]) { |
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53 | matched = false; |
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54 | break; |
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55 | } |
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56 | } |
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57 | if (matched) { |
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58 | return i; |
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59 | } |
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60 | } |
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61 | return -1; |
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62 | } |
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63 | |
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64 | /** |
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65 | * Find the nth occurrence of the given byte b in a UTF-8 encoded string |
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66 | * @param utf a byte array containing a UTF-8 encoded string |
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67 | * @param start starting offset |
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68 | * @param length the length of byte array |
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69 | * @param b the byte to find |
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70 | * @param n the desired occurrence of the given byte |
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71 | * @return position that nth occurrence of the given byte if exists; otherwise -1 |
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72 | */ |
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73 | public static int findNthByte(byte [] utf, int start, int length, byte b, int n) { |
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74 | int pos = -1; |
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75 | int nextStart = start; |
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76 | for (int i = 0; i < n; i++) { |
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77 | pos = findByte(utf, nextStart, length, b); |
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78 | if (pos < 0) { |
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79 | return pos; |
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80 | } |
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81 | nextStart = pos + 1; |
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82 | } |
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83 | return pos; |
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84 | } |
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85 | |
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86 | /** |
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87 | * Find the nth occurrence of the given byte b in a UTF-8 encoded string |
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88 | * @param utf a byte array containing a UTF-8 encoded string |
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89 | * @param b the byte to find |
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90 | * @param n the desired occurrence of the given byte |
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91 | * @return position that nth occurrence of the given byte if exists; otherwise -1 |
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92 | */ |
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93 | public static int findNthByte(byte [] utf, byte b, int n) { |
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94 | return findNthByte(utf, 0, utf.length, b, n); |
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95 | } |
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96 | |
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97 | } |
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98 | |
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