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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__