// Copyright (c) 2006, Google Inc.
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//
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// range_map.h: Range maps.
//
// A range map associates a range of addresses with a specific object.  This
// is useful when certain objects of variable size are located within an
// address space.  The range map makes it simple to determine which object is
// associated with a specific address, which may be any address within the
// range associated with an object.
//
// Author: Mark Mentovai

#ifndef PROCESSOR_RANGE_MAP_H__
#define PROCESSOR_RANGE_MAP_H__


#include <map>


namespace google_breakpad {


template<typename AddressType, typename EntryType>
class RangeMap {
 public:
  RangeMap() : map_() {}

  // Inserts a range into the map.  Returns false for a parameter error,
  // or if the location of the range would conflict with a range already
  // stored in the map.
  bool StoreRange(const AddressType &base,
                  const AddressType &size,
                  const EntryType &entry);

  // Locates the range encompassing the supplied address.  If there is
  // no such range, returns false.  entry_base and entry_size, if non-NULL,
  // are set to the base and size of the entry's range.
  bool RetrieveRange(const AddressType &address, EntryType *entry,
                     AddressType *entry_base, AddressType *entry_size) const;

  // Locates the range encompassing the supplied address, if one exists.
  // If no range encompasses the supplied address, locates the nearest range
  // to the supplied address that is lower than the address.  Returns false
  // if no range meets these criteria.  entry_base and entry_size, if
  // non-NULL, are set to the base and size of the entry's range.
  bool RetrieveNearestRange(const AddressType &address, EntryType *entry,
                            AddressType *entry_base, AddressType *entry_size)
                            const;

  // Treating all ranges as a list ordered by the address spaces that they
  // occupy, locates the range at the index specified by index.  Returns
  // false if index is larger than the number of ranges stored.  entry_base
  // and entry_size, if non-NULL, are set to the base and size of the entry's
  // range.
  //
  // RetrieveRangeAtIndex is not optimized for speedy operation.
  bool RetrieveRangeAtIndex(int index, EntryType *entry,
                            AddressType *entry_base, AddressType *entry_size)
                            const;

  // Returns the number of ranges stored in the RangeMap.
  int GetCount() const;

  // Empties the range map, restoring it to the state it was when it was
  // initially created.
  void Clear();

 private:
  class Range {
   public:
    Range(const AddressType &base, const EntryType &entry)
        : base_(base), entry_(entry) {}

    AddressType base() const { return base_; }
    EntryType entry() const { return entry_; }

   private:
    // The base address of the range.  The high address does not need to
    // be stored, because RangeMap uses it as the key to the map.
    const AddressType base_;

    // The entry corresponding to a range.
    const EntryType entry_;
  };

  // Convenience types.
  typedef std::map<AddressType, Range> AddressToRangeMap;
  typedef typename AddressToRangeMap::const_iterator MapConstIterator;
  typedef typename AddressToRangeMap::value_type MapValue;

  // Maps the high address of each range to a EntryType.
  AddressToRangeMap map_;
};


}  // namespace google_breakpad


#endif  // PROCESSOR_RANGE_MAP_H__
