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 // Copyright (c) 2006, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 // contained_range_map.h: Hierarchically-organized range maps.

 //

 // A contained range map is similar to a standard range map, except it allows

 // objects to be organized hierarchically.  A contained range map allows

 // objects to contain other objects.  It is not sensitive to the order that

 // objects are added to the map: larger, more general, containing objects

 // may be added either before or after smaller, more specific, contained

 // ones.

 //

 // Contained range maps guarantee that each object may only contain smaller

 // objects than itself, and that a parent object may only contain child

 // objects located entirely within the parent's address space.  Attempts

 // to introduce objects (via StoreRange) that violate these rules will fail.

 // Retrieval (via RetrieveRange) always returns the most specific (smallest)

 // object that contains the address being queried.  Note that while it is

 // not possible to insert two objects into a map that have exactly the same

 // geometry (base address and size), it is possible to completely mask a

 // larger object by inserting smaller objects that entirely fill the larger

 // object's address space.

 //

 // Internally, contained range maps are implemented as a tree.  Each tree

 // node except for the root node describes an object in the map.  Each node

 // maintains its list of children in a map similar to a standard range map,

 // keyed by the highest address that each child occupies.  Each node's

 // children occupy address ranges entirely within the node.  The root node

 // is the only node directly accessible to the user, and represents the

 // entire address space.

 //

 // Author: Mark Mentovai

 #ifndef PROCESSOR_CONTAINED_RANGE_MAP_H__

 #define PROCESSOR_CONTAINED_RANGE_MAP_H__

 #include <map>

 namespace google_breakpad {

 // Forward declarations (for later friend declarations of specialized template).

 template<class, class> class ContainedRangeMapSerializer;

 template<typename AddressType, typename EntryType>

 class ContainedRangeMap {

  public:

   // The default constructor creates a ContainedRangeMap with no geometry

   // and no entry, and as such is only suitable for the root node of a

   // ContainedRangeMap tree.

   ContainedRangeMap() : base_(), entry_(), map_(NULL) {}

   ~ContainedRangeMap();

   // Inserts a range into the map.  If the new range is encompassed by

   // an existing child range, the new range is passed into the child range's

   // StoreRange method.  If the new range encompasses any existing child

   // ranges, those child ranges are moved to the new range, becoming

   // grandchildren of this ContainedRangeMap.  Returns false for a

   // parameter error, or if the ContainedRangeMap hierarchy guarantees

   // would be violated.

   bool StoreRange(const AddressType &base,

                   const AddressType &size,

                   const EntryType &entry);

   // Retrieves the most specific (smallest) descendant range encompassing

   // the specified address.  This method will only return entries held by

   // child ranges, and not the entry contained by |this|.  This is necessary

   // to support a sparsely-populated root range.  If no descendant range

   // encompasses the address, returns false.

   bool RetrieveRange(const AddressType &address, EntryType *entry) const;

   // Removes all children.  Note that Clear only removes descendants,

   // leaving the node on which it is called intact.  Because the only

   // meaningful things contained by a root node are descendants, this

   // is sufficient to restore an entire ContainedRangeMap to its initial

   // empty state when called on the root node.

   void Clear();

  private:

   friend class ContainedRangeMapSerializer<AddressType, EntryType>;

   friend class ModuleComparer;

   // AddressToRangeMap stores pointers.  This makes reparenting simpler in

   // StoreRange, because it doesn't need to copy entire objects.

   typedef std::map<AddressType, ContainedRangeMap *> AddressToRangeMap;

   typedef typename AddressToRangeMap::const_iterator MapConstIterator;

   typedef typename AddressToRangeMap::iterator MapIterator;

   typedef typename AddressToRangeMap::value_type MapValue;

   // Creates a new ContainedRangeMap with the specified base address, entry,

   // and initial child map, which may be NULL.  This is only used internally

   // by ContainedRangeMap when it creates a new child.

   ContainedRangeMap(const AddressType &base, const EntryType &entry,

                     AddressToRangeMap *map)

       : base_(base), entry_(entry), map_(map) {}

   // The base address of this range.  The high address does not need to

   // be stored, because it is used as the key to an object in its parent's

   // map, and all ContainedRangeMaps except for the root range are contained

   // within maps.  The root range does not actually contain an entry, so its

   // base_ field is meaningless, and the fact that it has no parent and thus

   // no key is unimportant.  For this reason, the base_ field should only be

   // is accessed on child ContainedRangeMap objects, and never on |this|.

   const AddressType base_;

   // The entry corresponding to this range.  The root range does not

   // actually contain an entry, so its entry_ field is meaningless.  For

   // this reason, the entry_ field should only be accessed on child

   // ContainedRangeMap objects, and never on |this|.

   const EntryType entry_;

   // The map containing child ranges, keyed by each child range's high

   // address.  This is a pointer to avoid allocating map structures for

   // leaf nodes, where they are not needed.

   AddressToRangeMap *map_;

 };

 }  // namespace google_breakpad

 #endif  // PROCESSOR_CONTAINED_RANGE_MAP_H__