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 28  
 29  // static_map-inl.h: StaticMap implementation.
 30  //
 31  // See static_map.h for documentation.
 32  //
 33  // Author: Siyang Xie (lambxsy@google.com)
 34  
 35  
 36  #ifndef PROCESSOR_STATIC_MAP_INL_H__
 37  #define PROCESSOR_STATIC_MAP_INL_H__
 38  
 39  #include "processor/static_map.h"
 40  #include "processor/static_map_iterator-inl.h"
 41  #include "processor/logging.h"
 42  
 43  namespace google_breakpad {
 44  
 45  template<typename Key, typename Value, typename Compare>
 46  StaticMap<Key, Value, Compare>::StaticMap(const char* raw_data)
 47      : raw_data_(raw_data),
 48        compare_() {
 49    // First 4 Bytes store the number of nodes.
 50    num_nodes_ = *(reinterpret_cast<const uint32_t*>(raw_data_));
 51  
 52    offsets_ = reinterpret_cast<const uint32_t*>(
 53        raw_data_ + sizeof(num_nodes_));
 54  
 55    keys_ = reinterpret_cast<const Key*>(
 56        raw_data_ + (1 + num_nodes_) * sizeof(uint32_t));
 57  }
 58  
 59  // find(), lower_bound() and upper_bound() implement binary search algorithm.
 60  template<typename Key, typename Value, typename Compare>
 61  StaticMapIterator<Key, Value, Compare>
 62  StaticMap<Key, Value, Compare>::find(const Key& key) const {
 63    int begin = 0;
 64    int end = num_nodes_;
 65    int middle;
 66    int compare_result;
 67    while (begin < end) {
 68      middle = begin + (end - begin) / 2;
 69      compare_result = compare_(key, GetKeyAtIndex(middle));
 70      if (compare_result == 0)
 71        return IteratorAtIndex(middle);
 72      if (compare_result < 0) {
 73        end = middle;
 74      } else {
 75        begin = middle + 1;
 76      }
 77    }
 78    return this->end();
 79  }
 80  
 81  template<typename Key, typename Value, typename Compare>
 82  StaticMapIterator<Key, Value, Compare>
 83  StaticMap<Key, Value, Compare>::lower_bound(const Key& key) const {
 84    int begin = 0;
 85    int end = num_nodes_;
 86    int middle;
 87    int comp_result;
 88    while (begin < end) {
 89      middle = begin + (end - begin) / 2;
 90      comp_result = compare_(key, GetKeyAtIndex(middle));
 91      if (comp_result == 0)
 92        return IteratorAtIndex(middle);
 93      if (comp_result < 0) {
 94        end = middle;
 95      } else {
 96        begin = middle + 1;
 97      }
 98    }
 99    return IteratorAtIndex(begin);
100  }
101  
102  template<typename Key, typename Value, typename Compare>
103  StaticMapIterator<Key, Value, Compare>
104  StaticMap<Key, Value, Compare>::upper_bound(const Key& key) const {
105    int begin = 0;
106    int end = num_nodes_;
107    int middle;
108    int compare_result;
109    while (begin < end) {
110      middle = begin + (end - begin) / 2;
111      compare_result = compare_(key, GetKeyAtIndex(middle));
112      if (compare_result == 0)
113        return IteratorAtIndex(middle + 1);
114      if (compare_result < 0) {
115        end = middle;
116      } else {
117        begin = middle + 1;
118      }
119    }
120    return IteratorAtIndex(begin);
121  }
122  
123  template<typename Key, typename Value, typename Compare>
124  bool StaticMap<Key, Value, Compare>::ValidateInMemoryStructure() const {
125    // check the number of nodes is non-negative:
126    if (!raw_data_) return false;
127    int32_t num_nodes = *(reinterpret_cast<const int32_t*>(raw_data_));
128    if (num_nodes < 0) {
129      BPLOG(INFO) << "StaticMap check failed: negative number of nodes";
130      return false;
131    }
132  
133    int node_index = 0;
134    if (num_nodes_) {
135      uint64_t first_offset = sizeof(int32_t) * (num_nodes_ + 1)
136                             + sizeof(Key) * num_nodes_;
137      // Num_nodes_ is too large.
138      if (first_offset > 0xffffffffUL) {
139        BPLOG(INFO) << "StaticMap check failed: size exceeds limit";
140        return false;
141      }
142      if (offsets_[node_index] != static_cast<uint32_t>(first_offset)) {
143        BPLOG(INFO) << "StaticMap check failed: first node offset is incorrect";
144        return false;
145      }
146    }
147  
148    for (node_index = 1; node_index < num_nodes_; ++node_index) {
149      // Check offsets[i] is strictly increasing:
150      if (offsets_[node_index] <= offsets_[node_index - 1]) {
151        BPLOG(INFO) << "StaticMap check failed: node offsets non-increasing";
152        return false;
153      }
154      // Check Key[i] is strictly increasing as no duplicate keys are allowed.
155      if (compare_(GetKeyAtIndex(node_index),
156                   GetKeyAtIndex(node_index - 1)) <= 0) {
157        BPLOG(INFO) << "StaticMap check failed: node keys non-increasing";
158        return false;
159      }
160    }
161    return true;
162  }
163  
164  template<typename Key, typename Value, typename Compare>
165  const Key StaticMap<Key, Value, Compare>::GetKeyAtIndex(int index) const {
166    if (index < 0 || index >= num_nodes_) {
167      BPLOG(ERROR) << "Key index out of range error";
168      // Key type is required to be primitive type.  Return 0 if index is invalid.
169      return 0;
170    }
171    return keys_[index];
172  }
173  
174  }  // namespace google_breakpad
175  
176  #endif  // PROCESSOR_STATIC_MAP_INL_H__