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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

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

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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 {

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

template<class, class> class RangeMapSerializer;

// Determines what happens when two ranges overlap.

enum class MergeRangeStrategy {

  // When two ranges overlap, the new range fails to be inserted. The default

  // strategy.

  kExclusiveRanges,

  // The range with the lower base address will be truncated such that it's

  // high address is one less than the range above it.

  kTruncateLower,

  // The range with the greater high address has its range truncated such that

  // its base address is one higher than the range below it.

  kTruncateUpper

};

template<typename AddressType, typename EntryType>

class RangeMap {

 public:

  RangeMap() : merge_strategy_(MergeRangeStrategy::kExclusiveRanges), map_() {}

  void SetMergeStrategy(MergeRangeStrategy strat) { merge_strategy_ = strat; }

  MergeRangeStrategy GetMergeStrategy() const { return merge_strategy_; }

  // 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.  If enable_shrink_down is true and there is an overlap

  // between the current range and some other range (already in the map),

  // shrink down the range which ends at a higher address.

  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, entry_delta, and entry_size, if

  // non-NULL, are set to the base, delta, and size of the entry's range.

  // A positive entry delta (> 0) indicates that there was an overlap and the

  // entry was shrunk down (original start address was increased by delta).

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

                     AddressType *entry_base, AddressType *entry_delta,

                     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, entry_delta, and entry_size,

  // if non-NULL, are set to the base, delta, and size of the entry's range.

  // A positive entry delta (> 0) indicates that there was an overlap and the

  // entry was shrunk down (original start address was increased by delta).

  bool RetrieveNearestRange(const AddressType &address, EntryType *entry,

                            AddressType *entry_base, AddressType *entry_delta,

                            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,

  // entry_delta, and entry_size, if non-NULL, are set to the base, delta, and

  // size of the entry's range.

  // A positive entry delta (> 0) indicates that there was an overlap and the

  // entry was shrunk down (original start address was increased by delta).

//

  // RetrieveRangeAtIndex is not optimized for speedy operation.

  bool RetrieveRangeAtIndex(int index, EntryType *entry,

                            AddressType *entry_base, AddressType *entry_delta,

                            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:

  // Friend declarations.

  friend class ModuleComparer;

  friend class RangeMapSerializer<AddressType, EntryType>;

  // Same a StoreRange() with the only exception that the |delta| can be

  // passed in.

  bool StoreRangeInternal(const AddressType &base, const AddressType &delta,

                          const AddressType &size, const EntryType &entry);

  class Range {

   public:

    Range(const AddressType &base, const AddressType &delta,

          const EntryType &entry)

        : base_(base), delta_(delta), entry_(entry) {}

    AddressType base() const { return base_; }

    AddressType delta() const { return delta_; }

    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 delta when the range is shrunk down.

    const AddressType delta_;

    // 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;

  MergeRangeStrategy merge_strategy_;

  // Maps the high address of each range to a EntryType.

  AddressToRangeMap map_;

};

}  // namespace google_breakpad

#endif  // PROCESSOR_RANGE_MAP_H__