// 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__