1 | /*
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2 | * IncrementRange.java
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3 | * Copyright (C) 2000-2001 Stuart Yeates
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4 | *
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5 | * This program is free software; you can redistribute it and/or modify
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6 | * it under the terms of the GNU General Public License as published by
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7 | * the Free Software Foundation; either version 2 of the License, or
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8 | * (at your option) any later version.
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9 | *
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10 | * This program is distributed in the hope that it will be useful,
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11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 | * GNU General Public License for more details.
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14 | *
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15 | * You should have received a copy of the GNU General Public License
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16 | * along with this program; if not, write to the Free Software
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17 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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18 | */
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19 |
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20 | // the package we're in
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21 | package org.greenstone.gsdl3.selfContained;
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22 |
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23 | // java standard library classes used
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24 | import java.io.IOException;
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25 | import java.io.Reader;
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26 | import java.io.Serializable;
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27 | import java.io.StringReader;
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28 | import java.io.StringWriter;
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29 | import java.io.Writer;
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30 |
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31 | /**
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32 | * Class IncrementRange increments strings and streams over a limited range of Characters.
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33 | *
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34 | *
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35 | * @author <a href="http://www.cs.waikato.ac.nz/~say1/">stuart yeates</a> (<a href="mailto:[email protected]">[email protected]</a>) at the <a href="http://www.nzdl.org">New Zealand Digital Library</a>
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36 | * @version $Revision: 5663 $
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37 | * @see Increment
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38 | *
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39 | */
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40 | final public class IncrementRange
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41 | extends Increment
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42 | implements Cloneable, Serializable
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43 | {
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44 | /**
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45 | * Create an IncrementRange which counts between first and last inclusive
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46 | *
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47 | * @param first the first character in the range
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48 | * @param last the last character in the range
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49 | * @see Increment
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50 | */
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51 | IncrementRange(char first, char last){
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52 | this.first = first;
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53 | this.last = last;
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54 | }
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55 | /**
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56 | * Create a default IncrementRange
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57 | *
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58 | * @see Increment
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59 | */
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60 | IncrementRange(){
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61 | }
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62 |
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63 | /**
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64 | * Create a IncrementRange over all Unicode characters
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65 | *
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66 | * @see Increment
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67 | */
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68 | IncrementRange(boolean b){
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69 | if (true) {
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70 | this.first = Character.MIN_VALUE;
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71 | this.last = Character.MAX_VALUE;
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72 | }
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73 | }
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74 | /** the last character in out range */
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75 | private char first = ' ';
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76 | /** the last character in out range */
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77 | private char last = 'z';
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78 |
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79 | /**
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80 | * Increment a stream of characters, reading from the reader and writing the incremented characters to the writer
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81 | *
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82 | * @exception java.io.Error if any of the characters in the string are outside the range of first-last
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83 | * @param str the string to be incremented
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84 | * @return the incremented string
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85 | * @see Increment
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86 | */
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87 | long incrementStream(Reader rdr, Writer wtr) {
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88 | try {
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89 | long count = 0; // the return value
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90 |
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91 | int i = rdr.read();
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92 | boolean carry = true;
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93 |
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94 | while (i != -1) {
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95 | char c = (char) i;
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96 |
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97 | // check the validity of the character we're about to increment
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98 | if (c < first || c > last)
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99 | throw new Error("Character '" + c + "' is ouside range");
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100 |
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101 | if (c == last) {
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102 | if (carry == true) {
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103 | wtr.write(first);
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104 | carry = true;
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105 | } else {
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106 | wtr.write(c);
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107 | carry = false;
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108 | }
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109 | } else {
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110 | if (carry == true) {
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111 | wtr.write(++c);
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112 | carry = false;
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113 | } else {
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114 | wtr.write(c);
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115 | carry = false;
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116 | }
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117 | }
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118 | count++;
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119 |
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120 | // read the next character
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121 | i = rdr.read();
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122 | }
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123 | if (carry == true) {
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124 | wtr.write(first);
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125 | count++;
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126 | }
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127 | return count;
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128 | } catch (IOException e) {
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129 | System.err.println("IOException in incrementStream()");
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130 | throw new Error(e.toString());
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131 | }
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132 | }
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133 |
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134 | /**
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135 | * Increment a string of characters
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136 | *
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137 | * @exception java.lang.Error if any of the characters in the string are outside the range of first-last
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138 | * @param str the string to be incremented
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139 | * @return the incremented string
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140 | * @see Increment
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141 | */
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142 | public final String incrementString(String str) {
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143 | StringBuffer buffer = new StringBuffer();
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144 | if (str.equals("")) {
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145 | buffer.append(first);
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146 | return buffer.toString();
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147 | } else {
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148 | boolean carry = true;
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149 | for (int i=0;i<str.length();i++) {
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150 | char c = str.charAt(i);
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151 | if (c < first || c > last)
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152 | throw new Error("Character '" + c + "' is ouside range");
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153 |
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154 | if (c == last) {
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155 | if (carry == true) {
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156 | buffer.append(first);
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157 | carry = true;
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158 | } else {
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159 | buffer.append(c);
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160 | carry = false;
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161 | }
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162 | } else {
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163 | if (carry == true) {
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164 | buffer.append(++c);
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165 | carry = false;
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166 | } else {
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167 | buffer.append(c);
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168 | carry = false;
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169 | }
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170 | }
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171 | }
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172 | if (carry == true)
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173 | buffer.append(first);
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174 | }
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175 | return buffer.toString();
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176 | }
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177 |
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178 |
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179 | /**
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180 | * Test the incrementing of strings (never returns)
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181 | */
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182 | public static void testStringIncrement() throws IOException
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183 | {
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184 | IncrementRange n = new IncrementRange ();
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185 | try {
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186 | String tmp = "";
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187 | System.out.println(stringToHex(tmp));
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188 | while (true) {
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189 | //checkStr(tmp);
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190 | tmp = n.incrementString(tmp);
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191 | n.checkStr(tmp);
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192 | }
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193 | } catch (Exception e) {
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194 | System.out.println("Caught exception: " + e);
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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 | * Test the incrementing of streams (never returns)
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201 | *
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202 | */
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203 | public static void testStreamIncrement()
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204 | {
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205 | IncrementRange n = new IncrementRange ();
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206 | try {
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207 | long counter = 0;
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208 | String tmp = "";
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209 | System.out.println(stringToHex(tmp));
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210 | while (true) {
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211 | //checkStr(tmp);
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212 | String tmp2 = n.incrementString(tmp);
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213 | StringWriter wtr = new StringWriter();
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214 | n.incrementStream(new StringReader(tmp),wtr);
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215 | if (!tmp2.equals(wtr.toString()))
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216 | throw new Exception("Error: \"" + tmp2 +
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217 | "\" and \"" + tmp2 +
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218 | "\"");
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219 | counter++;
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220 | if (counter % 1000000 == 0)
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221 | System.out.println(counter + " " + tmp);
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222 |
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223 | tmp = tmp2;
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224 | }
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225 | } catch (Exception e) {
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226 | System.out.println("Caught exception: " + e);
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227 | }
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228 | }
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229 |
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230 | /**
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231 | * Tests stream incrementing
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232 | *
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233 | *
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234 | */
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235 | public static void main(String args[])
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236 | {
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237 | testStreamIncrement();
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238 | }
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239 | }
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240 |
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