static_contained_range_map.h

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// static_contained_range_map.h: StaticContainedRangeMap.
//
// StaticContainedRangeMap is similar to ContainedRangeMap.  However,
// StaticContainedRangeMap wraps a StaticMap instead of std::map, and does not
// support dynamic operations like StoreRange(...).
// StaticContainedRangeMap provides same RetrieveRange(...) interfaces as
// ContainedRangeMap.
//
// Please see contained_range_map.h for more documentation.
//
// Author: Siyang Xie (lambxsy@google.com)

#ifndef PROCESSOR_STATIC_CONTAINED_RANGE_MAP_H__
#define PROCESSOR_STATIC_CONTAINED_RANGE_MAP_H__

#include "processor/static_map-inl.h"

namespace google_breakpad {

template<typename AddressType, typename EntryType>
class StaticContainedRangeMap {
 public:
  StaticContainedRangeMap(): base_(), entry_size_(), entry_ptr_(), map_() { }
  explicit StaticContainedRangeMap(const char *base);

  // 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, const EntryType *&entry) const;

 private:
  friend class ModuleComparer;
  // AddressToRangeMap stores pointers.  This makes reparenting simpler in
  // StoreRange, because it doesn't need to copy entire objects.
  typedef StaticContainedRangeMap* SelfPtr;
  typedef
  StaticMap<AddressType, StaticContainedRangeMap> AddressToRangeMap;
  typedef typename AddressToRangeMap::const_iterator MapConstIterator;

  // 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|.
  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|.
  uint32_t entry_size_;
  const EntryType *entry_ptr_;

  // 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_STATIC_CONTAINED_RANGE_MAP_H__