/thirdparty/breakpad/processor/static_map.h

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 28
 29// static_map.h: StaticMap.
 30//
 31// StaticMap provides lookup interfaces and iterators similar as stl::map's.
 32// These lookup operations are purely Read-Only, thus memory
 33// allocation & deallocation is mostly avoided (intentionally).
 34//
 35// The chunk of memory should contain data with pre-defined pattern:
 36// **************** header ***************
 37// uint32 (4 bytes): number of nodes
 38// uint32 (4 bytes): address offset of node1's mapped_value
 39// uint32 (4 bytes): address offset of node2's mapped_value
 40// ...
 41// uint32 (4 bytes): address offset of nodeN's mapped_value
 42//
 43// ************* Key array ************
 44// (X bytes): node1's key
 45// (X bytes): node2's key
 46// ...
 47// (X bytes): nodeN's key
 48//
 49// ************* Value array **********
 50// (? bytes): node1's mapped_value
 51// (? bytes): node2's mapped_value
 52// ...
 53// (? bytes): nodeN's mapped_value
 54//
 55// REQUIREMENT: Key type MUST be primitive type or pointers so that:
 56// X = sizeof(typename Key);
 57//
 58// Note: since address offset is stored as uint32, user should keep in mind that
 59// StaticMap only supports up to 4GB size of memory data.
 60
 61// Author: Siyang Xie (lambxsy@google.com)
 62
 63
 64#ifndef PROCESSOR_STATIC_MAP_H__
 65#define PROCESSOR_STATIC_MAP_H__
 66
 67#include "processor/static_map_iterator-inl.h"
 68
 69namespace google_breakpad {
 70
 71// Default functor to compare keys.
 72template<typename Key>
 73class DefaultCompare {
 74 public:
 75  int operator()(const Key &k1, const Key &k2) const {
 76    if (k1 < k2) return -1;
 77    if (k1 == k2) return 0;
 78    return 1;
 79  }
 80};
 81
 82template<typename Key, typename Value, typename Compare = DefaultCompare<Key> >
 83class StaticMap {
 84 public:
 85  typedef StaticMapIterator<Key, Value, Compare> iterator;
 86  typedef StaticMapIterator<Key, Value, Compare> const_iterator;
 87
 88  StaticMap() : raw_data_(0),
 89                num_nodes_(0),
 90                offsets_(0),
 91                compare_() { }
 92
 93  explicit StaticMap(const char* raw_data);
 94
 95  inline bool empty() const { return num_nodes_ == 0; }
 96  inline unsigned int size() const { return num_nodes_; }
 97
 98  // Return iterators.
 99  inline iterator begin() const { return IteratorAtIndex(0); }
100  inline iterator last() const { return IteratorAtIndex(num_nodes_ - 1); }
101  inline iterator end() const { return IteratorAtIndex(num_nodes_); }
102  inline iterator IteratorAtIndex(int index) const {
103    return iterator(raw_data_, index);
104  }
105
106  // Lookup operations.
107  iterator find(const Key &k) const;
108
109  // lower_bound(k) searches in a sorted range for the first element that has a
110  // key not less than the argument k.
111  iterator lower_bound(const Key &k) const;
112
113  // upper_bound(k) searches in a sorted range for the first element that has a
114  // key greater than the argument k.
115  iterator upper_bound(const Key &k) const;
116
117  // Checks if the underlying memory data conforms to the predefined pattern:
118  // first check the number of nodes is non-negative,
119  // then check both offsets and keys are strictly increasing (sorted).
120  bool ValidateInMemoryStructure() const;
121
122 private:
123  const Key GetKeyAtIndex(int i) const;
124
125  // Start address of a raw memory chunk with serialized data.
126  const char* raw_data_;
127
128  // Number of nodes in the static map.
129  u_int32_t num_nodes_;
130
131  // Array of offset addresses for stored values.
132  // For example:
133  // address_of_i-th_node_value = raw_data_ + offsets_[i]
134  const u_int32_t* offsets_;
135
136  // keys_[i] = key of i_th node
137  const Key* keys_;
138
139  Compare compare_;
140};
141
142}  // namespace google_breakpad
143
144#endif  // PROCESSOR_STATIC_MAP_H__