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1 // Copyright (c) 2006, Google Inc. |
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2 // All rights reserved. |
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3 // |
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4 // Redistribution and use in source and binary forms, with or without |
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5 // modification, are permitted provided that the following conditions are |
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6 // met: |
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7 // |
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8 // * Redistributions of source code must retain the above copyright |
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9 // notice, this list of conditions and the following disclaimer. |
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10 // * Redistributions in binary form must reproduce the above |
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11 // copyright notice, this list of conditions and the following disclaimer |
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12 // in the documentation and/or other materials provided with the |
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13 // distribution. |
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14 // * Neither the name of Google Inc. nor the names of its |
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15 // contributors may be used to endorse or promote products derived from |
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16 // this software 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 |
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22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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29 |
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30 // contained_range_map.h: Hierarchically-organized range maps. |
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31 // |
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32 // A contained range map is similar to a standard range map, except it allows |
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33 // objects to be organized hierarchically. A contained range map allows |
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34 // objects to contain other objects. It is not sensitive to the order that |
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35 // objects are added to the map: larger, more general, containing objects |
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36 // may be added either before or after smaller, more specific, contained |
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37 // ones. |
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38 // |
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39 // Contained range maps guarantee that each object may only contain smaller |
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40 // objects than itself, and that a parent object may only contain child |
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41 // objects located entirely within the parent's address space. Attempts |
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42 // to introduce objects (via StoreRange) that violate these rules will fail. |
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43 // Retrieval (via RetrieveRange) always returns the most specific (smallest) |
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44 // object that contains the address being queried. Note that while it is |
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45 // not possible to insert two objects into a map that have exactly the same |
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46 // geometry (base address and size), it is possible to completely mask a |
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47 // larger object by inserting smaller objects that entirely fill the larger |
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48 // object's address space. |
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49 // |
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50 // Internally, contained range maps are implemented as a tree. Each tree |
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51 // node except for the root node describes an object in the map. Each node |
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52 // maintains its list of children in a map similar to a standard range map, |
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53 // keyed by the highest address that each child occupies. Each node's |
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54 // children occupy address ranges entirely within the node. The root node |
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55 // is the only node directly accessible to the user, and represents the |
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56 // entire address space. |
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57 // |
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58 // Author: Mark Mentovai |
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59 |
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60 #ifndef PROCESSOR_CONTAINED_RANGE_MAP_H__ |
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61 #define PROCESSOR_CONTAINED_RANGE_MAP_H__ |
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62 |
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63 |
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64 #include <map> |
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65 |
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66 |
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67 namespace google_breakpad { |
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68 |
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69 // Forward declarations (for later friend declarations of specialized template). |
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70 template<class, class> class ContainedRangeMapSerializer; |
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71 |
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72 template<typename AddressType, typename EntryType> |
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73 class ContainedRangeMap { |
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74 public: |
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75 // The default constructor creates a ContainedRangeMap with no geometry |
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76 // and no entry, and as such is only suitable for the root node of a |
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77 // ContainedRangeMap tree. |
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78 ContainedRangeMap() : base_(), entry_(), map_(NULL) {} |
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79 |
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80 ~ContainedRangeMap(); |
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81 |
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82 // Inserts a range into the map. If the new range is encompassed by |
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83 // an existing child range, the new range is passed into the child range's |
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84 // StoreRange method. If the new range encompasses any existing child |
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85 // ranges, those child ranges are moved to the new range, becoming |
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86 // grandchildren of this ContainedRangeMap. Returns false for a |
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87 // parameter error, or if the ContainedRangeMap hierarchy guarantees |
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88 // would be violated. |
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89 bool StoreRange(const AddressType &base, |
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90 const AddressType &size, |
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91 const EntryType &entry); |
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92 |
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93 // Retrieves the most specific (smallest) descendant range encompassing |
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94 // the specified address. This method will only return entries held by |
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95 // child ranges, and not the entry contained by |this|. This is necessary |
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96 // to support a sparsely-populated root range. If no descendant range |
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97 // encompasses the address, returns false. |
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98 bool RetrieveRange(const AddressType &address, EntryType *entry) const; |
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99 |
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100 // Removes all children. Note that Clear only removes descendants, |
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101 // leaving the node on which it is called intact. Because the only |
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102 // meaningful things contained by a root node are descendants, this |
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103 // is sufficient to restore an entire ContainedRangeMap to its initial |
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104 // empty state when called on the root node. |
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105 void Clear(); |
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106 |
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107 private: |
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108 friend class ContainedRangeMapSerializer<AddressType, EntryType>; |
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109 friend class ModuleComparer; |
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110 |
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111 // AddressToRangeMap stores pointers. This makes reparenting simpler in |
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112 // StoreRange, because it doesn't need to copy entire objects. |
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113 typedef std::map<AddressType, ContainedRangeMap *> AddressToRangeMap; |
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114 typedef typename AddressToRangeMap::const_iterator MapConstIterator; |
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115 typedef typename AddressToRangeMap::iterator MapIterator; |
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116 typedef typename AddressToRangeMap::value_type MapValue; |
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117 |
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118 // Creates a new ContainedRangeMap with the specified base address, entry, |
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119 // and initial child map, which may be NULL. This is only used internally |
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120 // by ContainedRangeMap when it creates a new child. |
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121 ContainedRangeMap(const AddressType &base, const EntryType &entry, |
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122 AddressToRangeMap *map) |
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123 : base_(base), entry_(entry), map_(map) {} |
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124 |
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125 // The base address of this range. The high address does not need to |
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126 // be stored, because it is used as the key to an object in its parent's |
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127 // map, and all ContainedRangeMaps except for the root range are contained |
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128 // within maps. The root range does not actually contain an entry, so its |
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129 // base_ field is meaningless, and the fact that it has no parent and thus |
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130 // no key is unimportant. For this reason, the base_ field should only be |
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131 // is accessed on child ContainedRangeMap objects, and never on |this|. |
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132 const AddressType base_; |
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133 |
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134 // The entry corresponding to this range. The root range does not |
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135 // actually contain an entry, so its entry_ field is meaningless. For |
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136 // this reason, the entry_ field should only be accessed on child |
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137 // ContainedRangeMap objects, and never on |this|. |
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138 const EntryType entry_; |
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139 |
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140 // The map containing child ranges, keyed by each child range's high |
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141 // address. This is a pointer to avoid allocating map structures for |
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142 // leaf nodes, where they are not needed. |
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143 AddressToRangeMap *map_; |
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144 }; |
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145 |
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146 |
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147 } // namespace google_breakpad |
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148 |
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149 |
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150 #endif // PROCESSOR_CONTAINED_RANGE_MAP_H__ |