opensim-development – Blame information for rev 1
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1 | eva | 1 | /* |
2 | * Copyright (C) 2007-2008, Jeff Thompson |
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3 | * |
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4 | * All rights reserved. |
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5 | * |
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6 | * Redistribution and use in source and binary forms, with or without |
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7 | * modification, are permitted provided that the following conditions are met: |
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8 | * |
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9 | * * Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * * Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * * Neither the name of the copyright holder nor the names of its contributors |
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15 | * may be used to endorse or promote products derived from this software |
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16 | * without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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19 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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20 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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21 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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22 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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23 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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24 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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25 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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26 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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27 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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28 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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29 | */ |
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30 | |||
31 | using System; |
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32 | using System.Collections.Generic; |
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33 | |||
34 | namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog |
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35 | { |
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36 | public class ListPair : Functor2 |
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37 | { |
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38 | public ListPair(object head, object tail) : base(Atom.DOT, head, tail) |
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39 | { |
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40 | } |
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41 | |||
42 | public static object make(List<object> list) |
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43 | { |
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44 | if (list.Count <= 0) |
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45 | return Atom.NIL; |
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46 | |||
47 | object result = Atom.NIL; |
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48 | // Start from the end. |
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49 | for (int i = list.Count - 1; i >= 0; --i) |
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50 | result = new ListPair(list[i], result); |
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51 | return result; |
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52 | } |
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53 | |||
54 | public static object make(object[] array) |
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55 | { |
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56 | if (array.Length <= 0) |
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57 | return Atom.NIL; |
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58 | |||
59 | object result = Atom.NIL; |
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60 | // Start from the end. |
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61 | for (int i = array.Length - 1; i >= 0; --i) |
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62 | result = new ListPair(array[i], result); |
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63 | return result; |
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64 | } |
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65 | |||
66 | /// <summary> |
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67 | /// Return a ListPair version of array, where repeated elements |
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68 | /// (according to YP.termEqual) are removed. |
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69 | /// </summary> |
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70 | /// <param name="array"></param> |
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71 | /// <returns></returns> |
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72 | public static object makeWithoutRepeatedTerms(object[] array) |
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73 | { |
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74 | if (array.Length <= 0) |
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75 | return Atom.NIL; |
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76 | |||
77 | // Start from the end. |
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78 | object previousTerm = array[array.Length - 1]; |
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79 | object result = new ListPair(previousTerm, Atom.NIL); |
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80 | for (int i = array.Length - 2; i >= 0; --i) |
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81 | { |
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82 | object term = array[i]; |
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83 | if (YP.termEqual(term, previousTerm)) |
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84 | continue; |
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85 | result = new ListPair(term, result); |
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86 | previousTerm = term; |
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87 | } |
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88 | return result; |
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89 | } |
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90 | |||
91 | /// <summary> |
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92 | /// Return a ListPair version of array, where repeated elements |
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93 | /// (according to YP.termEqual) are removed. |
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94 | /// </summary> |
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95 | /// <param name="array"></param> |
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96 | /// <returns></returns> |
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97 | public static object makeWithoutRepeatedTerms(List<object> array) |
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98 | { |
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99 | if (array.Count <= 0) |
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100 | return Atom.NIL; |
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101 | |||
102 | // Start from the end. |
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103 | object previousTerm = array[array.Count - 1]; |
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104 | object result = new ListPair(previousTerm, Atom.NIL); |
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105 | for (int i = array.Count - 2; i >= 0; --i) |
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106 | { |
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107 | object term = array[i]; |
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108 | if (YP.termEqual(term, previousTerm)) |
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109 | continue; |
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110 | result = new ListPair(term, result); |
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111 | previousTerm = term; |
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112 | } |
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113 | return result; |
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114 | } |
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115 | |||
116 | public static object make(object element1) |
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117 | { |
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118 | return new ListPair(element1, Atom.NIL); |
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119 | } |
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120 | |||
121 | public static object make(object element1, object element2) |
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122 | { |
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123 | return new ListPair(element1, new ListPair(element2, Atom.NIL)); |
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124 | } |
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125 | |||
126 | public static object make(object element1, object element2, object element3) |
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127 | { |
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128 | return new ListPair(element1, |
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129 | new ListPair(element2, new ListPair(element3, Atom.NIL))); |
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130 | } |
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131 | |||
132 | /// <summary> |
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133 | /// Return an array of the elements in list or null if it is not |
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134 | /// a proper list. If list is Atom.NIL, return an array of zero elements. |
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135 | /// If the list or one of the tails of the list is Variable, raise an instantiation_error. |
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136 | /// This does not call YP.getValue on each element. |
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137 | /// </summary> |
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138 | /// <param name="list"></param> |
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139 | /// <returns></returns> |
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140 | public static object[] toArray(object list) |
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141 | { |
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142 | list = YP.getValue(list); |
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143 | if (list.Equals(Atom.NIL)) |
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144 | return new object[0]; |
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145 | |||
146 | List<object> result = new List<object>(); |
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147 | object element = list; |
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148 | while (true) { |
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149 | if (element == Atom.NIL) |
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150 | break; |
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151 | if (element is Variable) |
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152 | throw new PrologException(Atom.a("instantiation_error"), |
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153 | "List tail is an unbound variable"); |
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154 | if (!(element is Functor2 && ((Functor2)element)._name == Atom.DOT)) |
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155 | // Not a proper list. |
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156 | return null; |
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157 | result.Add(((Functor2)element)._arg1); |
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158 | element = YP.getValue(((Functor2)element)._arg2); |
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159 | } |
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160 | |||
161 | if (result.Count <= 0) |
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162 | return null; |
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163 | return result.ToArray(); |
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164 | } |
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165 | } |
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166 | } |