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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 //
8 //     * Redistributions of source code must retain the above copyright
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
13 // distribution.
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15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 template<typename AddressType, typename EntryType>
53 class RangeMap {
54  public:
RangeMap()55   RangeMap() : map_() {}
56 
57   // Inserts a range into the map.  Returns false for a parameter error,
58   // or if the location of the range would conflict with a range already
59   // stored in the map.
60   bool StoreRange(const AddressType &base,
61                   const AddressType &size,
62                   const EntryType &entry);
63 
64   // Locates the range encompassing the supplied address.  If there is
65   // no such range, returns false.  entry_base and entry_size, if non-NULL,
66   // are set to the base and size of the entry's range.
67   bool RetrieveRange(const AddressType &address, EntryType *entry,
68                      AddressType *entry_base, AddressType *entry_size) const;
69 
70   // Locates the range encompassing the supplied address, if one exists.
71   // If no range encompasses the supplied address, locates the nearest range
72   // to the supplied address that is lower than the address.  Returns false
73   // if no range meets these criteria.  entry_base and entry_size, if
74   // non-NULL, are set to the base and size of the entry's range.
75   bool RetrieveNearestRange(const AddressType &address, EntryType *entry,
76                             AddressType *entry_base, AddressType *entry_size)
77                             const;
78 
79   // Treating all ranges as a list ordered by the address spaces that they
80   // occupy, locates the range at the index specified by index.  Returns
81   // false if index is larger than the number of ranges stored.  entry_base
82   // and entry_size, if non-NULL, are set to the base and size of the entry's
83   // range.
84   //
85   // RetrieveRangeAtIndex is not optimized for speedy operation.
86   bool RetrieveRangeAtIndex(int index, EntryType *entry,
87                             AddressType *entry_base, AddressType *entry_size)
88                             const;
89 
90   // Returns the number of ranges stored in the RangeMap.
91   int GetCount() const;
92 
93   // Empties the range map, restoring it to the state it was when it was
94   // initially created.
95   void Clear();
96 
97  private:
98   // Friend declarations.
99   friend class ModuleComparer;
100   friend class RangeMapSerializer<AddressType, EntryType>;
101 
102   class Range {
103    public:
Range(const AddressType & base,const EntryType & entry)104     Range(const AddressType &base, const EntryType &entry)
105         : base_(base), entry_(entry) {}
106 
base()107     AddressType base() const { return base_; }
entry()108     EntryType entry() const { return entry_; }
109 
110    private:
111     // The base address of the range.  The high address does not need to
112     // be stored, because RangeMap uses it as the key to the map.
113     const AddressType base_;
114 
115     // The entry corresponding to a range.
116     const EntryType entry_;
117   };
118 
119   // Convenience types.
120   typedef std::map<AddressType, Range> AddressToRangeMap;
121   typedef typename AddressToRangeMap::const_iterator MapConstIterator;
122   typedef typename AddressToRangeMap::value_type MapValue;
123 
124   // Maps the high address of each range to a EntryType.
125   AddressToRangeMap map_;
126 };
127 
128 
129 }  // namespace google_breakpad
130 
131 
132 #endif  // PROCESSOR_RANGE_MAP_H__
133