1 | // Copyright (c) 2006, Google Inc. |
2 | // All rights reserved. |
3 | // |
4 | // Redistribution and use in source and binary forms, with or without |
5 | // modification, are permitted provided that the following conditions are |
6 | // met: |
7 | // |
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9 | // notice, this list of conditions and the following disclaimer. |
10 | // * Redistributions in binary form must reproduce the above |
11 | // copyright notice, this list of conditions and the following disclaimer |
12 | // in the documentation and/or other materials provided with the |
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15 | // contributors may be used to endorse or promote products derived from |
16 | // this software without specific prior written permission. |
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29 | |
30 | // range_map.h: Range maps. |
31 | // |
32 | // A range map associates a range of addresses with a specific object. This |
33 | // is useful when certain objects of variable size are located within an |
34 | // address space. The range map makes it simple to determine which object is |
35 | // associated with a specific address, which may be any address within the |
36 | // range associated with an object. |
37 | // |
38 | // Author: Mark Mentovai |
39 | |
40 | #ifndef PROCESSOR_RANGE_MAP_H__ |
41 | #define PROCESSOR_RANGE_MAP_H__ |
42 | |
43 | |
44 | #include <map> |
45 | |
46 | |
47 | namespace google_breakpad { |
48 | |
49 | // Forward declarations (for later friend declarations of specialized template). |
50 | template<class, class> class RangeMapSerializer; |
51 | |
52 | // Determines what happens when two ranges overlap. |
53 | enum class MergeRangeStrategy { |
54 | // When two ranges overlap, the new range fails to be inserted. The default |
55 | // strategy. |
56 | kExclusiveRanges, |
57 | |
58 | // The range with the lower base address will be truncated such that it's |
59 | // high address is one less than the range above it. |
60 | kTruncateLower, |
61 | |
62 | // The range with the greater high address has its range truncated such that |
63 | // its base address is one higher than the range below it. |
64 | kTruncateUpper |
65 | }; |
66 | |
67 | template<typename AddressType, typename EntryType> |
68 | class RangeMap { |
69 | public: |
70 | RangeMap() : merge_strategy_(MergeRangeStrategy::kExclusiveRanges), map_() {} |
71 | |
72 | void SetMergeStrategy(MergeRangeStrategy strat) { merge_strategy_ = strat; } |
73 | |
74 | MergeRangeStrategy GetMergeStrategy() const { return merge_strategy_; } |
75 | |
76 | // Inserts a range into the map. Returns false for a parameter error, |
77 | // or if the location of the range would conflict with a range already |
78 | // stored in the map. If enable_shrink_down is true and there is an overlap |
79 | // between the current range and some other range (already in the map), |
80 | // shrink down the range which ends at a higher address. |
81 | bool StoreRange(const AddressType& base, const AddressType& size, |
82 | const EntryType& entry); |
83 | |
84 | // Locates the range encompassing the supplied address. If there is no such |
85 | // range, returns false. entry_base, entry_delta, and entry_size, if |
86 | // non-NULL, are set to the base, delta, and size of the entry's range. |
87 | // A positive entry delta (> 0) indicates that there was an overlap and the |
88 | // entry was shrunk down (original start address was increased by delta). |
89 | bool RetrieveRange(const AddressType& address, EntryType* entry, |
90 | AddressType* entry_base, AddressType* entry_delta, |
91 | AddressType* entry_size) const; |
92 | |
93 | // Locates the range encompassing the supplied address, if one exists. |
94 | // If no range encompasses the supplied address, locates the nearest range |
95 | // to the supplied address that is lower than the address. Returns false |
96 | // if no range meets these criteria. entry_base, entry_delta, and entry_size, |
97 | // if non-NULL, are set to the base, delta, and size of the entry's range. |
98 | // A positive entry delta (> 0) indicates that there was an overlap and the |
99 | // entry was shrunk down (original start address was increased by delta). |
100 | bool RetrieveNearestRange(const AddressType& address, EntryType* entry, |
101 | AddressType* entry_base, AddressType* entry_delta, |
102 | AddressType* entry_size) const; |
103 | |
104 | // Treating all ranges as a list ordered by the address spaces that they |
105 | // occupy, locates the range at the index specified by index. Returns |
106 | // false if index is larger than the number of ranges stored. entry_base, |
107 | // entry_delta, and entry_size, if non-NULL, are set to the base, delta, and |
108 | // size of the entry's range. |
109 | // A positive entry delta (> 0) indicates that there was an overlap and the |
110 | // entry was shrunk down (original start address was increased by delta). |
111 | // |
112 | // RetrieveRangeAtIndex is not optimized for speedy operation. |
113 | bool RetrieveRangeAtIndex(int index, EntryType* entry, |
114 | AddressType* entry_base, AddressType* entry_delta, |
115 | AddressType* entry_size) const; |
116 | |
117 | // Returns the number of ranges stored in the RangeMap. |
118 | int GetCount() const; |
119 | |
120 | // Empties the range map, restoring it to the state it was when it was |
121 | // initially created. |
122 | void Clear(); |
123 | |
124 | private: |
125 | // Friend declarations. |
126 | friend class ModuleComparer; |
127 | friend class RangeMapSerializer<AddressType, EntryType>; |
128 | |
129 | // Same a StoreRange() with the only exception that the |delta| can be |
130 | // passed in. |
131 | bool StoreRangeInternal(const AddressType& base, const AddressType& delta, |
132 | const AddressType& size, const EntryType& entry); |
133 | |
134 | class Range { |
135 | public: |
136 | Range(const AddressType& base, const AddressType& delta, |
137 | const EntryType& entry) |
138 | : base_(base), delta_(delta), entry_(entry) {} |
139 | |
140 | AddressType base() const { return base_; } |
141 | AddressType delta() const { return delta_; } |
142 | EntryType entry() const { return entry_; } |
143 | |
144 | private: |
145 | // The base address of the range. The high address does not need to |
146 | // be stored, because RangeMap uses it as the key to the map. |
147 | const AddressType base_; |
148 | |
149 | // The delta when the range is shrunk down. |
150 | const AddressType delta_; |
151 | |
152 | // The entry corresponding to a range. |
153 | const EntryType entry_; |
154 | }; |
155 | |
156 | // Convenience types. |
157 | typedef std::map<AddressType, Range> AddressToRangeMap; |
158 | typedef typename AddressToRangeMap::const_iterator MapConstIterator; |
159 | typedef typename AddressToRangeMap::value_type MapValue; |
160 | |
161 | MergeRangeStrategy merge_strategy_; |
162 | |
163 | // Maps the high address of each range to a EntryType. |
164 | AddressToRangeMap map_; |
165 | }; |
166 | |
167 | |
168 | } // namespace google_breakpad |
169 | |
170 | |
171 | #endif // PROCESSOR_RANGE_MAP_H__ |
172 | |