static_map_iterator.h

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// static_map_iterator.h: StaticMapIterator template class declaration.
//
// StaticMapIterator provides increment and decrement operators to iterate
// through a StaticMap map.  It does not provide *, -> operators, user should
// use GetKeyPtr(), GetKey(), GetValuePtr() interfaces to retrieve data or
// pointer to data.  StaticMapIterator is essentially a const_iterator.
//
// Author: Siyang Xie (lambxsy@google.com)


#ifndef PROCESSOR_STATIC_MAP_ITERATOR_H__
#define PROCESSOR_STATIC_MAP_ITERATOR_H__

#include "google_breakpad/common/breakpad_types.h"

namespace google_breakpad {

// Forward declaration.
template<typename Key, typename Value, typename Compare> class StaticMap;

// StaticMapIterator does not support operator*() or operator->(),
// User should use GetKey(), GetKeyPtr(), GetValuePtr() instead;
template<typename Key, typename Value, typename Compare>
class StaticMapIterator {
 public:
  // Constructors.
  StaticMapIterator(): index_(-1), base_(NULL) { }

  // Increment & Decrement operators:
  StaticMapIterator& operator++();
  StaticMapIterator operator++(int post_fix_operator);

  StaticMapIterator& operator--();
  StaticMapIterator operator--(int post_fix_operator);

  // Interface for retrieving data / pointer to data.
  const Key* GetKeyPtr() const;

  // Run time error will occur if GetKey() is called on an invalid iterator.
  inline const Key GetKey() const { return *GetKeyPtr(); }

  // return a raw memory pointer that points to the start address of value.
  const char* GetValueRawPtr() const;

  // return a reinterpret-casted pointer to the value.
  inline const Value* GetValuePtr() const {
    return reinterpret_cast<const Value*>(GetValueRawPtr());
  }

  bool operator==(const StaticMapIterator& x) const;
  bool operator!=(const StaticMapIterator& x) const;

  // Check if this iterator is valid.
  // If iterator is invalid, user is forbidden to use ++/-- operator
  // or interfaces for retrieving data / pointer to data.
  bool IsValid() const;

 private:
  friend class StaticMap<Key, Value, Compare>;

  // Only StaticMap can call this constructor.
  explicit StaticMapIterator(const char* base, const int32_t &index);

  // Index of node that the iterator is pointing to.
  int32_t index_;

  // Beginning address of the serialized map data.
  const char* base_;

  // Number of nodes in the map.  Use it to identify end() iterator.
  int32_t num_nodes_;

  // offsets_ is an array of offset addresses of mapped values.
  // For example:
  // address_of_i-th_node_value = base_ + offsets_[i]
  const uint32_t* offsets_;

  // keys_[i] = key of i_th node.
  const Key* keys_;
};

}  // namespace google_breakpad

#endif  // PROCESSOR_STATIC_MAP_ITERATOR_H__