opensim – 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; |
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33 | using System.Collections.Generic; |
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34 | |||
35 | namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog |
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36 | { |
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37 | /// <summary> |
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38 | /// A BagofAnswers holds answers for bagof and setof. |
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39 | /// </summary> |
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40 | public class BagofAnswers |
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41 | { |
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42 | private object _template; |
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43 | private Variable[] _freeVariables; |
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44 | private Dictionary<object[], List<object>> _bagForFreeVariables; |
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45 | private List<object> _findallBagArray; |
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46 | private static TermArrayEqualityComparer _termArrayEqualityComparer = |
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47 | new TermArrayEqualityComparer(); |
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48 | |||
49 | /// <summary> |
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50 | /// To get the free variables, split off any existential qualifiers from Goal such as the X in |
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51 | /// "X ^ f(Y)", get the set of unbound variables in Goal that are not qualifiers, then remove |
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52 | /// the unbound variables that are qualifiers as well as the unbound variables in Template. |
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53 | /// </summary> |
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54 | /// <param name="Template"></param> |
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55 | /// <param name="Goal"></param> |
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56 | public BagofAnswers(object Template, object Goal) |
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57 | { |
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58 | _template = Template; |
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59 | |||
60 | // First get the set of variables that are not free variables. |
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61 | List<Variable> variableSet = new List<Variable>(); |
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62 | YP.addUniqueVariables(Template, variableSet); |
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63 | object UnqualifiedGoal = YP.getValue(Goal); |
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64 | while (UnqualifiedGoal is Functor2 && ((Functor2)UnqualifiedGoal)._name == Atom.HAT) |
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65 | { |
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66 | YP.addUniqueVariables(((Functor2)UnqualifiedGoal)._arg1, variableSet); |
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67 | UnqualifiedGoal = YP.getValue(((Functor2)UnqualifiedGoal)._arg2); |
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68 | } |
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69 | |||
70 | // Remember how many non-free variables there are so we can find the unique free variables |
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71 | // that are added. |
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72 | int nNonFreeVariables = variableSet.Count; |
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73 | YP.addUniqueVariables(UnqualifiedGoal, variableSet); |
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74 | int nFreeVariables = variableSet.Count - nNonFreeVariables; |
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75 | if (nFreeVariables == 0) |
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76 | { |
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77 | // There were no free variables added, so we won't waste time with _bagForFreeVariables. |
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78 | _freeVariables = null; |
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79 | _findallBagArray = new List<object>(); |
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80 | } |
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81 | else |
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82 | { |
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83 | // Copy the free variables. |
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84 | _freeVariables = new Variable[nFreeVariables]; |
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85 | for (int i = 0; i < nFreeVariables; ++i) |
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86 | _freeVariables[i] = variableSet[i + nNonFreeVariables]; |
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87 | |||
88 | _bagForFreeVariables = new Dictionary<object[], List<object>>(_termArrayEqualityComparer); |
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89 | } |
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90 | } |
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91 | |||
92 | public void add() |
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93 | { |
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94 | if (_freeVariables == null) |
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95 | // The goal has bound the values in _template but we don't bother with _freeVariables. |
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96 | _findallBagArray.Add(YP.makeCopy(_template, new Variable.CopyStore())); |
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97 | else |
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98 | { |
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99 | // The goal has bound the values in _template and _freeVariables. |
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100 | // Find the entry for this set of _freeVariables values. |
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101 | object[] freeVariableValues = new object[_freeVariables.Length]; |
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102 | for (int i = 0; i < _freeVariables.Length; ++i) |
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103 | freeVariableValues[i] = YP.getValue(_freeVariables[i]); |
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104 | List<object> bagArray; |
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105 | if (!_bagForFreeVariables.TryGetValue(freeVariableValues, out bagArray)) |
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106 | { |
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107 | bagArray = new List<object>(); |
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108 | _bagForFreeVariables[freeVariableValues] = bagArray; |
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109 | } |
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110 | |||
111 | // Now copy the template and add to the bag for the freeVariables values. |
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112 | bagArray.Add(YP.makeCopy(_template, new Variable.CopyStore())); |
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113 | } |
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114 | } |
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115 | |||
116 | // disable warning on l1, don't see how we can |
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117 | // code this differently |
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118 | #pragma warning disable 0168, 0219 |
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119 | |||
120 | /// <summary> |
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121 | /// For each result, unify the _freeVariables and unify bagArrayVariable with the associated bag. |
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122 | /// </summary> |
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123 | /// <param name="bagArrayVariable">this is unified with the List<object> of matches for template that |
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124 | /// corresponds to the bindings for freeVariables. Be very careful: this does not unify with a Prolog |
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125 | /// list.</param> |
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126 | /// <returns></returns> |
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127 | public IEnumerable<bool> resultArray(Variable bagArrayVariable) |
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128 | { |
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129 | if (_freeVariables == null) |
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130 | { |
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131 | // No unbound free variables, so we only filled one bag. If empty, bagof fails. |
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132 | if (_findallBagArray.Count > 0) |
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133 | { |
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134 | foreach (bool l1 in bagArrayVariable.unify(_findallBagArray)) |
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135 | yield return false; |
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136 | } |
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137 | } |
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138 | else |
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139 | { |
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140 | foreach (KeyValuePair<object[], List<object>> valuesAndBag in _bagForFreeVariables) |
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141 | { |
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142 | foreach (bool l1 in YP.unifyArrays(_freeVariables, valuesAndBag.Key)) |
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143 | { |
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144 | foreach (bool l2 in bagArrayVariable.unify(valuesAndBag.Value)) |
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145 | yield return false; |
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146 | } |
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147 | // Debug: Should we free memory of the answers already returned? |
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148 | } |
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149 | } |
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150 | } |
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151 | |||
152 | /// <summary> |
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153 | /// For each result, unify the _freeVariables and unify Bag with the associated bag. |
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154 | /// </summary> |
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155 | /// <param name="Bag"></param> |
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156 | /// <returns></returns> |
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157 | public IEnumerable<bool> result(object Bag) |
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158 | { |
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159 | Variable bagArrayVariable = new Variable(); |
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160 | foreach (bool l1 in resultArray(bagArrayVariable)) |
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161 | { |
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162 | foreach (bool l2 in YP.unify(Bag, ListPair.make((List<object>)bagArrayVariable.getValue()))) |
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163 | yield return false; |
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164 | } |
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165 | } |
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166 | |||
167 | /// <summary> |
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168 | /// For each result, unify the _freeVariables and unify Bag with the associated bag which is sorted |
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169 | /// with duplicates removed, as in setof. |
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170 | /// </summary> |
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171 | /// <param name="Bag"></param> |
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172 | /// <returns></returns> |
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173 | public IEnumerable<bool> resultSet(object Bag) |
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174 | { |
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175 | Variable bagArrayVariable = new Variable(); |
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176 | foreach (bool l1 in resultArray(bagArrayVariable)) |
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177 | { |
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178 | List<object> bagArray = (List<object>)bagArrayVariable.getValue(); |
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179 | YP.sortArray(bagArray); |
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180 | foreach (bool l2 in YP.unify(Bag, ListPair.makeWithoutRepeatedTerms(bagArray))) |
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181 | yield return false; |
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182 | } |
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183 | } |
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184 | |||
185 | public static IEnumerable<bool> bagofArray |
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186 | (object Template, object Goal, IEnumerable<bool> goalIterator, Variable bagArrayVariable) |
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187 | { |
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188 | BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal); |
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189 | foreach (bool l1 in goalIterator) |
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190 | bagOfAnswers.add(); |
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191 | return bagOfAnswers.resultArray(bagArrayVariable); |
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192 | } |
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193 | |||
194 | public static IEnumerable<bool> bagof |
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195 | (object Template, object Goal, IEnumerable<bool> goalIterator, object Bag) |
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196 | { |
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197 | BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal); |
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198 | foreach (bool l1 in goalIterator) |
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199 | bagOfAnswers.add(); |
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200 | return bagOfAnswers.result(Bag); |
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201 | } |
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202 | |||
203 | public static IEnumerable<bool> setof |
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204 | (object Template, object Goal, IEnumerable<bool> goalIterator, object Bag) |
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205 | { |
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206 | BagofAnswers bagOfAnswers = new BagofAnswers(Template, Goal); |
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207 | foreach (bool l1 in goalIterator) |
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208 | bagOfAnswers.add(); |
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209 | return bagOfAnswers.resultSet(Bag); |
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210 | } |
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211 | #pragma warning restore 0168, 0219 |
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212 | |||
213 | /// <summary> |
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214 | /// A TermArrayEqualityComparer implements IEqualityComparer to compare two object arrays using YP.termEqual. |
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215 | /// </summary> |
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216 | private class TermArrayEqualityComparer : IEqualityComparer<object[]> |
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217 | { |
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218 | public bool Equals(object[] array1, object[] array2) |
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219 | { |
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220 | if (array1.Length != array2.Length) |
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221 | return false; |
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222 | for (int i = 0; i < array1.Length; ++i) |
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223 | { |
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224 | if (!YP.termEqual(array1[i], array2[i])) |
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225 | return false; |
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226 | } |
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227 | return true; |
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228 | } |
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229 | |||
230 | public int GetHashCode(object[] array) |
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231 | { |
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232 | int hashCode = 0; |
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233 | for (int i = 0; i < array.Length; ++i) |
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234 | hashCode ^= array[i].GetHashCode(); |
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235 | return hashCode; |
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236 | } |
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237 | } |
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238 | } |
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239 | } |