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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtCore module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 #ifndef QCACHE_H |
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43 #define QCACHE_H |
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44 |
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45 #include <QtCore/qhash.h> |
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46 |
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47 QT_BEGIN_HEADER |
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48 |
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49 QT_BEGIN_NAMESPACE |
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50 |
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51 QT_MODULE(Core) |
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52 |
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53 template <class Key, class T> |
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54 class QCache |
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55 { |
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56 struct Node { |
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57 inline Node() : keyPtr(0) {} |
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58 inline Node(T *data, int cost) |
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59 : keyPtr(0), t(data), c(cost), p(0), n(0) {} |
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60 const Key *keyPtr; T *t; int c; Node *p,*n; |
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61 }; |
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62 Node *f, *l; |
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63 QHash<Key, Node> hash; |
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64 void *unused; |
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65 int mx, total; |
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66 |
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67 inline void unlink(Node &n) { |
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68 if (n.p) n.p->n = n.n; |
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69 if (n.n) n.n->p = n.p; |
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70 if (l == &n) l = n.p; |
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71 if (f == &n) f = n.n; |
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72 total -= n.c; |
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73 delete n.t; |
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74 hash.remove(*n.keyPtr); |
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75 } |
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76 inline T *relink(const Key &key) { |
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77 typename QHash<Key, Node>::iterator i = hash.find(key); |
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78 if (typename QHash<Key, Node>::const_iterator(i) == hash.constEnd()) |
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79 return 0; |
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80 |
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81 Node &n = *i; |
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82 if (f != &n) { |
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83 if (n.p) n.p->n = n.n; |
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84 if (n.n) n.n->p = n.p; |
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85 if (l == &n) l = n.p; |
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86 n.p = 0; |
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87 n.n = f; |
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88 f->p = &n; |
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89 f = &n; |
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90 } |
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91 return n.t; |
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92 } |
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93 |
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94 Q_DISABLE_COPY(QCache) |
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95 |
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96 public: |
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97 inline explicit QCache(int maxCost = 100); |
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98 #ifdef QT3_SUPPORT |
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99 inline QT3_SUPPORT_CONSTRUCTOR QCache(int maxCost, int /* dummy */) |
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100 : f(0), l(0), mx(maxCost), total(0) {} |
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101 #endif |
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102 inline ~QCache() { clear(); } |
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103 |
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104 inline int maxCost() const { return mx; } |
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105 void setMaxCost(int m); |
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106 inline int totalCost() const { return total; } |
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107 |
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108 inline int size() const { return hash.size(); } |
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109 inline int count() const { return hash.size(); } |
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110 inline bool isEmpty() const { return hash.isEmpty(); } |
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111 inline QList<Key> keys() const { return hash.keys(); } |
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112 |
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113 void clear(); |
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114 |
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115 bool insert(const Key &key, T *object, int cost = 1); |
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116 T *object(const Key &key) const; |
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117 inline bool contains(const Key &key) const { return hash.contains(key); } |
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118 T *operator[](const Key &key) const; |
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119 |
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120 bool remove(const Key &key); |
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121 T *take(const Key &key); |
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122 |
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123 private: |
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124 void trim(int m); |
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125 |
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126 #ifdef QT3_SUPPORT |
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127 inline QT3_SUPPORT T *find(const Key &key) const { return object(key); } |
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128 #endif |
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129 |
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130 }; |
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131 |
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132 template <class Key, class T> |
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133 inline QCache<Key, T>::QCache(int amaxCost) |
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134 : f(0), l(0), unused(0), mx(amaxCost), total(0) {} |
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135 |
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136 template <class Key, class T> |
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137 inline void QCache<Key,T>::clear() |
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138 { while (f) { delete f->t; f = f->n; } |
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139 hash.clear(); l = 0; total = 0; } |
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140 |
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141 template <class Key, class T> |
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142 inline void QCache<Key,T>::setMaxCost(int m) |
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143 { mx = m; trim(mx); } |
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144 |
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145 template <class Key, class T> |
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146 inline T *QCache<Key,T>::object(const Key &key) const |
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147 { return const_cast<QCache<Key,T>*>(this)->relink(key); } |
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148 |
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149 template <class Key, class T> |
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150 inline T *QCache<Key,T>::operator[](const Key &key) const |
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151 { return object(key); } |
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152 |
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153 template <class Key, class T> |
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154 inline bool QCache<Key,T>::remove(const Key &key) |
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155 { |
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156 typename QHash<Key, Node>::iterator i = hash.find(key); |
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157 if (typename QHash<Key, Node>::const_iterator(i) == hash.constEnd()) { |
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158 return false; |
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159 } else { |
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160 unlink(*i); |
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161 return true; |
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162 } |
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163 } |
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164 |
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165 template <class Key, class T> |
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166 inline T *QCache<Key,T>::take(const Key &key) |
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167 { |
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168 typename QHash<Key, Node>::iterator i = hash.find(key); |
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169 if (i == hash.end()) |
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170 return 0; |
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171 |
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172 Node &n = *i; |
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173 T *t = n.t; |
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174 n.t = 0; |
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175 unlink(n); |
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176 return t; |
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177 } |
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178 |
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179 template <class Key, class T> |
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180 bool QCache<Key,T>::insert(const Key &akey, T *aobject, int acost) |
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181 { |
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182 remove(akey); |
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183 if (acost > mx) { |
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184 delete aobject; |
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185 return false; |
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186 } |
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187 trim(mx - acost); |
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188 Node sn(aobject, acost); |
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189 typename QHash<Key, Node>::iterator i = hash.insert(akey, sn); |
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190 total += acost; |
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191 Node *n = &i.value(); |
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192 n->keyPtr = &i.key(); |
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193 if (f) f->p = n; |
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194 n->n = f; |
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195 f = n; |
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196 if (!l) l = f; |
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197 return true; |
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198 } |
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199 |
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200 template <class Key, class T> |
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201 void QCache<Key,T>::trim(int m) |
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202 { |
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203 Node *n = l; |
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204 while (n && total > m) { |
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205 Node *u = n; |
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206 n = n->p; |
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207 if (qIsDetached(*u->t)) |
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208 unlink(*u); |
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209 } |
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210 } |
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211 |
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212 QT_END_NAMESPACE |
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213 |
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214 QT_END_HEADER |
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215 |
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216 #endif // QCACHE_H |