/thirdparty/breakpad/processor/range_map-inl.h

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 29
 30// range_map-inl.h: Range map implementation.
 31//
 32// See range_map.h for documentation.
 33//
 34// Author: Mark Mentovai
 35
 36#ifndef PROCESSOR_RANGE_MAP_INL_H__
 37#define PROCESSOR_RANGE_MAP_INL_H__
 38
 39
 40#include <assert.h>
 41
 42#include "processor/range_map.h"
 43#include "processor/logging.h"
 44
 45
 46namespace google_breakpad {
 47
 48
 49template<typename AddressType, typename EntryType>
 50bool RangeMap<AddressType, EntryType>::StoreRange(const AddressType &base,
 51                                                  const AddressType &size,
 52                                                  const EntryType &entry) {
 53  AddressType high = base + size - 1;
 54
 55  // Check for undersize or overflow.
 56  if (size <= 0 || high < base) {
 57    // The processor will hit this case too frequently with common symbol
 58    // files in the size == 0 case, which is more suited to a DEBUG channel.
 59    // Filter those out since there's no DEBUG channel at the moment.
 60    BPLOG_IF(INFO, size != 0) << "StoreRange failed, " << HexString(base) <<
 61                                 "+" << HexString(size) << ", " <<
 62                                 HexString(high);
 63    return false;
 64  }
 65
 66  // Ensure that this range does not overlap with another one already in the
 67  // map.
 68  MapConstIterator iterator_base = map_.lower_bound(base);
 69  MapConstIterator iterator_high = map_.lower_bound(high);
 70
 71  if (iterator_base != iterator_high) {
 72    // Some other range begins in the space used by this range.  It may be
 73    // contained within the space used by this range, or it may extend lower.
 74    // Regardless, it is an error.
 75    AddressType other_base = iterator_base->second.base();
 76    AddressType other_size = iterator_base->first - other_base + 1;
 77    BPLOG(INFO) << "StoreRange failed, an existing range is contained by or "
 78                   "extends lower than the new range: new " <<
 79                   HexString(base) << "+" << HexString(size) << ", existing " <<
 80                   HexString(other_base) << "+" << HexString(other_size);
 81    return false;
 82  }
 83
 84  if (iterator_high != map_.end()) {
 85    if (iterator_high->second.base() <= high) {
 86      // The range above this one overlaps with this one.  It may fully
 87      // contain this range, or it may begin within this range and extend
 88      // higher.  Regardless, it's an error.
 89      AddressType other_base = iterator_high->second.base();
 90      AddressType other_size = iterator_high->first - other_base + 1;
 91      BPLOG(INFO) << "StoreRange failed, an existing range contains or "
 92                     "extends higher than the new range: new " <<
 93                     HexString(base) << "+" << HexString(size) <<
 94                     ", existing " <<
 95                     HexString(other_base) << "+" << HexString(other_size);
 96      return false;
 97    }
 98  }
 99
100  // Store the range in the map by its high address, so that lower_bound can
101  // be used to quickly locate a range by address.
102  map_.insert(MapValue(high, Range(base, entry)));
103  return true;
104}
105
106
107template<typename AddressType, typename EntryType>
108bool RangeMap<AddressType, EntryType>::RetrieveRange(
109    const AddressType &address, EntryType *entry,
110    AddressType *entry_base, AddressType *entry_size) const {
111  BPLOG_IF(ERROR, !entry) << "RangeMap::RetrieveRange requires |entry|";
112  assert(entry);
113
114  MapConstIterator iterator = map_.lower_bound(address);
115  if (iterator == map_.end())
116    return false;
117
118  // The map is keyed by the high address of each range, so |address| is
119  // guaranteed to be lower than the range's high address.  If |range| is
120  // not directly preceded by another range, it's possible for address to
121  // be below the range's low address, though.  When that happens, address
122  // references something not within any range, so return false.
123  if (address < iterator->second.base())
124    return false;
125
126  *entry = iterator->second.entry();
127  if (entry_base)
128    *entry_base = iterator->second.base();
129  if (entry_size)
130    *entry_size = iterator->first - iterator->second.base() + 1;
131
132  return true;
133}
134
135
136template<typename AddressType, typename EntryType>
137bool RangeMap<AddressType, EntryType>::RetrieveNearestRange(
138    const AddressType &address, EntryType *entry,
139    AddressType *entry_base, AddressType *entry_size) const {
140  BPLOG_IF(ERROR, !entry) << "RangeMap::RetrieveNearestRange requires |entry|";
141  assert(entry);
142
143  // If address is within a range, RetrieveRange can handle it.
144  if (RetrieveRange(address, entry, entry_base, entry_size))
145    return true;
146
147  // upper_bound gives the first element whose key is greater than address,
148  // but we want the first element whose key is less than or equal to address.
149  // Decrement the iterator to get there, but not if the upper_bound already
150  // points to the beginning of the map - in that case, address is lower than
151  // the lowest stored key, so return false.
152  MapConstIterator iterator = map_.upper_bound(address);
153  if (iterator == map_.begin())
154    return false;
155  --iterator;
156
157  *entry = iterator->second.entry();
158  if (entry_base)
159    *entry_base = iterator->second.base();
160  if (entry_size)
161    *entry_size = iterator->first - iterator->second.base() + 1;
162
163  return true;
164}
165
166
167template<typename AddressType, typename EntryType>
168bool RangeMap<AddressType, EntryType>::RetrieveRangeAtIndex(
169    int index, EntryType *entry,
170    AddressType *entry_base, AddressType *entry_size) const {
171  BPLOG_IF(ERROR, !entry) << "RangeMap::RetrieveRangeAtIndex requires |entry|";
172  assert(entry);
173
174  if (index >= GetCount()) {
175    BPLOG(ERROR) << "Index out of range: " << index << "/" << GetCount();
176    return false;
177  }
178
179  // Walk through the map.  Although it's ordered, it's not a vector, so it
180  // can't be addressed directly by index.
181  MapConstIterator iterator = map_.begin();
182  for (int this_index = 0; this_index < index; ++this_index)
183    ++iterator;
184
185  *entry = iterator->second.entry();
186  if (entry_base)
187    *entry_base = iterator->second.base();
188  if (entry_size)
189    *entry_size = iterator->first - iterator->second.base() + 1;
190
191  return true;
192}
193
194
195template<typename AddressType, typename EntryType>
196int RangeMap<AddressType, EntryType>::GetCount() const {
197  return map_.size();
198}
199
200
201template<typename AddressType, typename EntryType>
202void RangeMap<AddressType, EntryType>::Clear() {
203  map_.clear();
204}
205
206
207}  // namespace google_breakpad
208
209
210#endif  // PROCESSOR_RANGE_MAP_INL_H__