aboutsummaryrefslogtreecommitdiff
path: root/src/processor/static_map.h
blob: 9723ab2a84649dcd8d35fe642fe887993d173bba (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
// Copyright 2010 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
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// static_map.h: StaticMap.
//
// StaticMap provides lookup interfaces and iterators similar as stl::map's.
// These lookup operations are purely Read-Only, thus memory
// allocation & deallocation is mostly avoided (intentionally).
//
// The chunk of memory should contain data with pre-defined pattern:
// **************** header ***************
// uint32 (4 bytes): number of nodes
// uint32 (4 bytes): address offset of node1's mapped_value
// uint32 (4 bytes): address offset of node2's mapped_value
// ...
// uint32 (4 bytes): address offset of nodeN's mapped_value
//
// ************* Key array ************
// (X bytes): node1's key
// (X bytes): node2's key
// ...
// (X bytes): nodeN's key
//
// ************* Value array **********
// (? bytes): node1's mapped_value
// (? bytes): node2's mapped_value
// ...
// (? bytes): nodeN's mapped_value
//
// REQUIREMENT: Key type MUST be primitive type or pointers so that:
// X = sizeof(typename Key);
//
// Note: since address offset is stored as uint32, user should keep in mind that
// StaticMap only supports up to 4GB size of memory data.

// Author: Siyang Xie (lambxsy@google.com)


#ifndef PROCESSOR_STATIC_MAP_H__
#define PROCESSOR_STATIC_MAP_H__

#include "processor/static_map_iterator-inl.h"

namespace google_breakpad {

// Default functor to compare keys.
template<typename Key>
class DefaultCompare {
 public:
  int operator()(const Key &k1, const Key &k2) const {
    if (k1 < k2) return -1;
    if (k1 == k2) return 0;
    return 1;
  }
};

template<typename Key, typename Value, typename Compare = DefaultCompare<Key> >
class StaticMap {
 public:
  typedef StaticMapIterator<Key, Value, Compare> iterator;
  typedef StaticMapIterator<Key, Value, Compare> const_iterator;

  StaticMap() : raw_data_(0),
                num_nodes_(0),
                offsets_(0),
                compare_() { }

  explicit StaticMap(const char* raw_data);

  inline bool empty() const { return num_nodes_ == 0; }
  inline unsigned int size() const { return num_nodes_; }

  // Return iterators.
  inline iterator begin() const { return IteratorAtIndex(0); }
  inline iterator last() const { return IteratorAtIndex(num_nodes_ - 1); }
  inline iterator end() const { return IteratorAtIndex(num_nodes_); }
  inline iterator IteratorAtIndex(int index) const {
    return iterator(raw_data_, index);
  }

  // Lookup operations.
  iterator find(const Key &k) const;

  // lower_bound(k) searches in a sorted range for the first element that has a
  // key not less than the argument k.
  iterator lower_bound(const Key &k) const;

  // upper_bound(k) searches in a sorted range for the first element that has a
  // key greater than the argument k.
  iterator upper_bound(const Key &k) const;

  // Checks if the underlying memory data conforms to the predefined pattern:
  // first check the number of nodes is non-negative,
  // then check both offsets and keys are strictly increasing (sorted).
  bool ValidateInMemoryStructure() const;

 private:
  const Key GetKeyAtIndex(int i) const;

  // Start address of a raw memory chunk with serialized data.
  const char* raw_data_;

  // Number of nodes in the static map.
  int32_t num_nodes_;

  // Array of offset addresses for stored values.
  // For example:
  // address_of_i-th_node_value = raw_data_ + offsets_[i]
  const uint32_t* offsets_;

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

  Compare compare_;
};

}  // namespace google_breakpad

#endif  // PROCESSOR_STATIC_MAP_H__