1 /* |
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2 * Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: |
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15 * |
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16 * SourceIterator can be used to traverse through the source file character at a time |
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17 * |
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18 */ |
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19 package com.nokia.tracecompiler.source; |
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20 |
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21 /** |
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22 * SourceIterator can be used to traverse through the source file character at a |
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23 * time. |
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24 * |
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25 */ |
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26 public class SourceIterator { |
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27 |
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28 /** |
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29 * The source parser |
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30 */ |
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31 private SourceParser parser; |
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32 |
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33 /** |
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34 * Index of next excluded area |
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35 */ |
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36 private int nextExcludedIndex; |
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37 |
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38 /** |
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39 * The type of next excluded area |
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40 */ |
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41 private int nextExcludedAreaType; |
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42 |
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43 /** |
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44 * Offset to the start of next excluded area |
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45 */ |
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46 private int nextExcludedStart; |
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47 |
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48 /** |
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49 * Offset to the end of next excluded area |
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50 */ |
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51 private int nextExcludedEnd; |
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52 |
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53 /** |
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54 * Index of next character to be fetched |
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55 */ |
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56 private int nextIndex; |
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57 |
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58 /** |
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59 * Index of character returned by latest call to next |
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60 */ |
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61 private int currentIndex; |
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62 |
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63 /** |
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64 * Index of character returned by previous call to next |
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65 */ |
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66 private int previousIndex; |
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67 |
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68 /** |
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69 * Search flags |
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70 */ |
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71 private int flags; |
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72 |
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73 /** |
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74 * Constructor |
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75 * |
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76 * @param parser |
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77 * source parser |
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78 * @param startIndex |
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79 * the index where to start |
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80 * @param flags |
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81 * the iterator flags |
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82 */ |
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83 SourceIterator(SourceParser parser, int startIndex, int flags) { |
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84 SourceDocumentInterface source = parser.getSource(); |
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85 if (startIndex >= source.getLength() |
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86 && ((flags & SourceParser.BACKWARD_SEARCH) != 0)) { |
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87 nextIndex = source.getLength() - 1; |
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88 } else { |
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89 nextIndex = startIndex; |
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90 } |
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91 this.parser = parser; |
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92 this.flags = flags; |
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93 if (hasNext()) { |
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94 boolean forward = (flags & SourceParser.BACKWARD_SEARCH) == 0; |
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95 nextExcludedIndex = parser.findExcludedAreaIndex(nextIndex); |
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96 if (nextExcludedIndex < 0) { |
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97 nextExcludedIndex = -1 - nextExcludedIndex; |
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98 if (forward) { |
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99 // Update increments the index, so it must be moved behind |
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100 // the start of search |
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101 nextExcludedIndex--; |
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102 } |
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103 } |
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104 // Increments / decrements the next excluded area according to |
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105 // search direction. If direction is backward, this decrements the |
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106 // index. In that case the above initialization has selected the |
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107 // index after the start of search index. If direction is forward, |
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108 // this increments the index. |
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109 updateExcludedIndex(); |
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110 // After the excluded index has been set, the white spaces and |
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111 // comments are skipped |
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112 if (forward) { |
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113 forwardSeekNext(); |
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114 } else { |
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115 backwardSeekNext(); |
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116 } |
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117 previousIndex = startIndex; |
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118 currentIndex = startIndex; |
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119 } |
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120 } |
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121 |
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122 /** |
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123 * Determines if there are more characters to process |
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124 * |
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125 * @return true if iterator has more characters |
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126 */ |
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127 public boolean hasNext() { |
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128 return (flags & SourceParser.BACKWARD_SEARCH) == 0 ? nextIndex < parser |
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129 .getSource().getLength() : nextIndex >= 0; |
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130 } |
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131 |
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132 /** |
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133 * Gets the next character from this iterator |
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134 * |
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135 * @return the next character |
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136 * @throws SourceParserException |
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137 * if there are no more characters |
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138 */ |
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139 public char next() throws SourceParserException { |
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140 char ret; |
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141 previousIndex = currentIndex; |
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142 currentIndex = nextIndex; |
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143 if ((flags & SourceParser.BACKWARD_SEARCH) == 0) { |
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144 ret = forwardNext(); |
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145 } else { |
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146 ret = backwardNext(); |
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147 } |
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148 return ret; |
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149 } |
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150 |
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151 /** |
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152 * Returns next character moving forward |
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153 * |
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154 * @return the character |
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155 * @throws SourceParserException |
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156 * if there are no more characters |
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157 */ |
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158 private char forwardNext() throws SourceParserException { |
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159 char c = parser.getSource().getChar(nextIndex); |
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160 nextIndex++; |
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161 forwardSeekNext(); |
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162 return c; |
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163 } |
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164 |
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165 /** |
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166 * Skips to next index |
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167 */ |
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168 private void forwardSeekNext() { |
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169 // Skips over the excluded area if the index enters one |
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170 boolean didSkip; |
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171 SourceDocumentInterface source = parser.getSource(); |
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172 try { |
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173 do { |
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174 didSkip = false; |
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175 if (nextIndex >= nextExcludedStart && nextExcludedStart != -1) { |
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176 // Skips if applicable. Otherwise just updates the next |
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177 // excluded |
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178 // area variables |
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179 if (isExcluded()) { |
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180 nextIndex = nextExcludedEnd; |
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181 } |
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182 updateExcludedIndex(); |
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183 } |
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184 if ((flags & SourceParser.SKIP_WHITE_SPACES) != 0) { |
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185 // Skips over white spaces |
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186 boolean wspFound = true; |
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187 do { |
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188 // If a white space is skipped, the excluded area check |
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189 // needs to be done again. didSkip flag controls that |
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190 if (nextIndex < source.getLength() |
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191 && Character.isWhitespace(source |
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192 .getChar(nextIndex))) { |
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193 nextIndex++; |
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194 didSkip = true; |
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195 } else { |
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196 wspFound = false; |
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197 } |
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198 } while (wspFound); |
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199 } |
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200 } while (didSkip); |
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201 } catch (SourceParserException e) { |
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202 // The exception must not be thrown out of this function |
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203 } |
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204 } |
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205 |
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206 /** |
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207 * Returns next character moving backward |
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208 * |
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209 * @return the character |
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210 * @throws SourceParserException |
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211 * if there are no more characters |
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212 */ |
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213 private char backwardNext() throws SourceParserException { |
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214 char c = parser.getSource().getChar(nextIndex); |
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215 nextIndex--; |
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216 backwardSeekNext(); |
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217 return c; |
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218 } |
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219 |
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220 /** |
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221 * Skips to previous index |
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222 */ |
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223 private void backwardSeekNext() { |
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224 // Skips over the excluded area if the index enters one |
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225 boolean didSkip; |
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226 SourceDocumentInterface source = parser.getSource(); |
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227 try { |
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228 do { |
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229 didSkip = false; |
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230 if (nextIndex <= nextExcludedEnd - 1) { |
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231 // Skips if applicable. Otherwise just updates the next |
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232 // excluded |
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233 // area variables |
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234 if (isExcluded()) { |
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235 nextIndex = nextExcludedStart - 1; |
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236 } |
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237 updateExcludedIndex(); |
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238 } |
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239 if ((flags & SourceParser.SKIP_WHITE_SPACES) != 0) { |
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240 boolean wspFound = true; |
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241 do { |
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242 // If a white space is skipped, the excluded area check |
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243 // needs to be done again. didSkip flag controls that |
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244 if (nextIndex >= 0 |
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245 && Character.isWhitespace(source |
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246 .getChar(nextIndex))) { |
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247 nextIndex--; |
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248 didSkip = true; |
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249 } else { |
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250 wspFound = false; |
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251 } |
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252 } while (wspFound); |
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253 } |
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254 } while (didSkip); |
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255 } catch (SourceParserException e) { |
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256 // The exception must not be thrown out of this function |
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257 } |
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258 } |
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259 |
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260 /** |
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261 * Updates the excluded area index |
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262 */ |
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263 private void updateExcludedIndex() { |
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264 if ((flags & SourceParser.BACKWARD_SEARCH) == 0) { |
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265 nextExcludedIndex++; |
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266 } else { |
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267 nextExcludedIndex--; |
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268 } |
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269 // Updates the values using the next excluded area |
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270 if (nextExcludedIndex >= 0 |
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271 && nextExcludedIndex < parser.getExcludedAreas().size()) { |
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272 SourceExcludedArea p = parser.getExcludedAreas().get( |
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273 nextExcludedIndex); |
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274 nextExcludedStart = p.getOffset(); |
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275 nextExcludedEnd = p.getOffset() + p.getLength(); |
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276 nextExcludedAreaType = p.getType(); |
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277 } else { |
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278 nextExcludedStart = -1; |
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279 nextExcludedEnd = -1; |
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280 } |
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281 } |
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282 |
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283 /** |
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284 * Returns the index where the next character will be fetched |
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285 * |
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286 * @return the index |
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287 */ |
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288 public int nextIndex() { |
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289 return nextIndex; |
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290 } |
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291 |
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292 /** |
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293 * Gets the index of the character returned by last call to next |
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294 * |
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295 * @return the index |
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296 */ |
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297 public int currentIndex() { |
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298 return currentIndex; |
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299 } |
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300 |
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301 /** |
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302 * Gets the index that preceeded the latest call to next |
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303 * |
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304 * @return the index |
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305 */ |
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306 public int previousIndex() { |
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307 return previousIndex; |
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308 } |
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309 |
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310 /** |
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311 * Gets the next character but does not move the iterator |
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312 * |
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313 * @return the next character |
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314 * @throws SourceParserException |
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315 * if there are no more characters |
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316 */ |
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317 public char peek() throws SourceParserException { |
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318 return parser.getSource().getChar(nextIndex); |
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319 } |
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320 |
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321 /** |
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322 * Determines if the iterator skipped over characters during last call to |
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323 * next |
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324 * |
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325 * @return true if skipped, false otherwise |
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326 */ |
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327 public boolean hasSkipped() { |
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328 return (flags & SourceParser.BACKWARD_SEARCH) == 0 ? currentIndex > previousIndex + 1 |
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329 : currentIndex < previousIndex - 1; |
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330 } |
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331 |
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332 /** |
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333 * Checks if the next area is skipped |
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334 * |
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335 * @return true is skipped |
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336 */ |
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337 private boolean isExcluded() { |
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338 return isExcluded(nextExcludedAreaType); |
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339 } |
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340 |
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341 /** |
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342 * Checks if the given type is skipped |
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343 * |
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344 * @param type |
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345 * the type |
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346 * @return true is skipped |
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347 */ |
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348 private boolean isExcluded(int type) { |
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349 return SourceParser.isExcluded(type, flags); |
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350 } |
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351 |
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352 } |
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