llvm.org GIT mirror llvm / cf0db29 include / llvm / ADT / StringMap.h
cf0db29

Tree @cf0db29 (Download .tar.gz)

StringMap.h @cf0db29raw · history · blame

  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
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
//===--- StringMap.h - String Hash table map interface ----------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the StringMap class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_STRINGMAP_H
#define LLVM_ADT_STRINGMAP_H

#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include <cstring>
#include <utility>

namespace llvm {
  template<typename ValueT>
  class StringMapConstIterator;
  template<typename ValueT>
  class StringMapIterator;
  template<typename ValueTy>
  class StringMapEntry;

/// StringMapEntryBase - Shared base class of StringMapEntry instances.
class StringMapEntryBase {
  unsigned StrLen;
public:
  explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}

  unsigned getKeyLength() const { return StrLen; }
};

/// StringMapImpl - This is the base class of StringMap that is shared among
/// all of its instantiations.
class StringMapImpl {
protected:
  // Array of NumBuckets pointers to entries, null pointers are holes.
  // TheTable[NumBuckets] contains a sentinel value for easy iteration. Followed
  // by an array of the actual hash values as unsigned integers.
  StringMapEntryBase **TheTable;
  unsigned NumBuckets;
  unsigned NumItems;
  unsigned NumTombstones;
  unsigned ItemSize;
protected:
  explicit StringMapImpl(unsigned itemSize)
      : TheTable(nullptr),
        // Initialize the map with zero buckets to allocation.
        NumBuckets(0), NumItems(0), NumTombstones(0), ItemSize(itemSize) {}
  StringMapImpl(StringMapImpl &&RHS)
      : TheTable(RHS.TheTable), NumBuckets(RHS.NumBuckets),
        NumItems(RHS.NumItems), NumTombstones(RHS.NumTombstones),
        ItemSize(RHS.ItemSize) {
    RHS.TheTable = nullptr;
    RHS.NumBuckets = 0;
    RHS.NumItems = 0;
    RHS.NumTombstones = 0;
  }

  StringMapImpl(unsigned InitSize, unsigned ItemSize);
  unsigned RehashTable(unsigned BucketNo = 0);

  /// LookupBucketFor - Look up the bucket that the specified string should end
  /// up in.  If it already exists as a key in the map, the Item pointer for the
  /// specified bucket will be non-null.  Otherwise, it will be null.  In either
  /// case, the FullHashValue field of the bucket will be set to the hash value
  /// of the string.
  unsigned LookupBucketFor(StringRef Key);

  /// FindKey - Look up the bucket that contains the specified key. If it exists
  /// in the map, return the bucket number of the key.  Otherwise return -1.
  /// This does not modify the map.
  int FindKey(StringRef Key) const;

  /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
  /// delete it.  This aborts if the value isn't in the table.
  void RemoveKey(StringMapEntryBase *V);

  /// RemoveKey - Remove the StringMapEntry for the specified key from the
  /// table, returning it.  If the key is not in the table, this returns null.
  StringMapEntryBase *RemoveKey(StringRef Key);
private:
  void init(unsigned Size);
public:
  static StringMapEntryBase *getTombstoneVal() {
    return (StringMapEntryBase*)-1;
  }

  unsigned getNumBuckets() const { return NumBuckets; }
  unsigned getNumItems() const { return NumItems; }

  bool empty() const { return NumItems == 0; }
  unsigned size() const { return NumItems; }

  void swap(StringMapImpl &Other) {
    std::swap(TheTable, Other.TheTable);
    std::swap(NumBuckets, Other.NumBuckets);
    std::swap(NumItems, Other.NumItems);
    std::swap(NumTombstones, Other.NumTombstones);
  }
};

/// StringMapEntry - This is used to represent one value that is inserted into
/// a StringMap.  It contains the Value itself and the key: the string length
/// and data.
template<typename ValueTy>
class StringMapEntry : public StringMapEntryBase {
  StringMapEntry(StringMapEntry &E) = delete;
public:
  ValueTy second;

  explicit StringMapEntry(unsigned strLen)
    : StringMapEntryBase(strLen), second() {}
  template <class InitTy>
  StringMapEntry(unsigned strLen, InitTy &&V)
      : StringMapEntryBase(strLen), second(std::forward<InitTy>(V)) {}

  StringRef getKey() const {
    return StringRef(getKeyData(), getKeyLength());
  }

  const ValueTy &getValue() const { return second; }
  ValueTy &getValue() { return second; }

  void setValue(const ValueTy &V) { second = V; }

  /// getKeyData - Return the start of the string data that is the key for this
  /// value.  The string data is always stored immediately after the
  /// StringMapEntry object.
  const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}

  StringRef first() const { return StringRef(getKeyData(), getKeyLength()); }

  /// Create - Create a StringMapEntry for the specified key and default
  /// construct the value.
  template <typename AllocatorTy, typename InitType>
  static StringMapEntry *Create(StringRef Key, AllocatorTy &Allocator,
                                InitType &&InitVal) {
    unsigned KeyLength = Key.size();

    // Allocate a new item with space for the string at the end and a null
    // terminator.
    unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
      KeyLength+1;
    unsigned Alignment = alignOf<StringMapEntry>();

    StringMapEntry *NewItem =
      static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));

    // Default construct the value.
    new (NewItem) StringMapEntry(KeyLength, std::forward<InitType>(InitVal));

    // Copy the string information.
    char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
    memcpy(StrBuffer, Key.data(), KeyLength);
    StrBuffer[KeyLength] = 0;  // Null terminate for convenience of clients.
    return NewItem;
  }

  template<typename AllocatorTy>
  static StringMapEntry *Create(StringRef Key, AllocatorTy &Allocator) {
    return Create(Key, Allocator, ValueTy());
  }

  /// Create - Create a StringMapEntry with normal malloc/free.
  template<typename InitType>
  static StringMapEntry *Create(StringRef Key, InitType &&InitVal) {
    MallocAllocator A;
    return Create(Key, A, std::forward<InitType>(InitVal));
  }

  static StringMapEntry *Create(StringRef Key) {
    return Create(Key, ValueTy());
  }

  /// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
  /// into a StringMapEntry, return the StringMapEntry itself.
  static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
    char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
    return *reinterpret_cast<StringMapEntry*>(Ptr);
  }

  /// Destroy - Destroy this StringMapEntry, releasing memory back to the
  /// specified allocator.
  template<typename AllocatorTy>
  void Destroy(AllocatorTy &Allocator) {
    // Free memory referenced by the item.
    unsigned AllocSize =
        static_cast<unsigned>(sizeof(StringMapEntry)) + getKeyLength() + 1;
    this->~StringMapEntry();
    Allocator.Deallocate(static_cast<void *>(this), AllocSize);
  }

  /// Destroy this object, releasing memory back to the malloc allocator.
  void Destroy() {
    MallocAllocator A;
    Destroy(A);
  }
};


/// StringMap - This is an unconventional map that is specialized for handling
/// keys that are "strings", which are basically ranges of bytes. This does some
/// funky memory allocation and hashing things to make it extremely efficient,
/// storing the string data *after* the value in the map.
template<typename ValueTy, typename AllocatorTy = MallocAllocator>
class StringMap : public StringMapImpl {
  AllocatorTy Allocator;
public:
  typedef StringMapEntry<ValueTy> MapEntryTy;
  
  StringMap() : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {}
  explicit StringMap(unsigned InitialSize)
    : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))) {}

  explicit StringMap(AllocatorTy A)
    : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))), Allocator(A) {}

  StringMap(unsigned InitialSize, AllocatorTy A)
    : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))),
      Allocator(A) {}

  StringMap(StringMap &&RHS)
      : StringMapImpl(std::move(RHS)), Allocator(std::move(RHS.Allocator)) {}

  StringMap &operator=(StringMap RHS) {
    StringMapImpl::swap(RHS);
    std::swap(Allocator, RHS.Allocator);
    return *this;
  }

  // FIXME: Implement copy operations if/when they're needed.

  AllocatorTy &getAllocator() { return Allocator; }
  const AllocatorTy &getAllocator() const { return Allocator; }

  typedef const char* key_type;
  typedef ValueTy mapped_type;
  typedef StringMapEntry<ValueTy> value_type;
  typedef size_t size_type;

  typedef StringMapConstIterator<ValueTy> const_iterator;
  typedef StringMapIterator<ValueTy> iterator;

  iterator begin() {
    return iterator(TheTable, NumBuckets == 0);
  }
  iterator end() {
    return iterator(TheTable+NumBuckets, true);
  }
  const_iterator begin() const {
    return const_iterator(TheTable, NumBuckets == 0);
  }
  const_iterator end() const {
    return const_iterator(TheTable+NumBuckets, true);
  }

  iterator find(StringRef Key) {
    int Bucket = FindKey(Key);
    if (Bucket == -1) return end();
    return iterator(TheTable+Bucket, true);
  }

  const_iterator find(StringRef Key) const {
    int Bucket = FindKey(Key);
    if (Bucket == -1) return end();
    return const_iterator(TheTable+Bucket, true);
  }

  /// lookup - Return the entry for the specified key, or a default
  /// constructed value if no such entry exists.
  ValueTy lookup(StringRef Key) const {
    const_iterator it = find(Key);
    if (it != end())
      return it->second;
    return ValueTy();
  }

  ValueTy &operator[](StringRef Key) {
    return insert(std::make_pair(Key, ValueTy())).first->second;
  }

  /// count - Return 1 if the element is in the map, 0 otherwise.
  size_type count(StringRef Key) const {
    return find(Key) == end() ? 0 : 1;
  }

  /// insert - Insert the specified key/value pair into the map.  If the key
  /// already exists in the map, return false and ignore the request, otherwise
  /// insert it and return true.
  bool insert(MapEntryTy *KeyValue) {
    unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
    StringMapEntryBase *&Bucket = TheTable[BucketNo];
    if (Bucket && Bucket != getTombstoneVal())
      return false;  // Already exists in map.

    if (Bucket == getTombstoneVal())
      --NumTombstones;
    Bucket = KeyValue;
    ++NumItems;
    assert(NumItems + NumTombstones <= NumBuckets);

    RehashTable();
    return true;
  }

  /// insert - Inserts the specified key/value pair into the map if the key
  /// isn't already in the map. The bool component of the returned pair is true
  /// if and only if the insertion takes place, and the iterator component of
  /// the pair points to the element with key equivalent to the key of the pair.
  std::pair<iterator, bool> insert(std::pair<StringRef, ValueTy> KV) {
    unsigned BucketNo = LookupBucketFor(KV.first);
    StringMapEntryBase *&Bucket = TheTable[BucketNo];
    if (Bucket && Bucket != getTombstoneVal())
      return std::make_pair(iterator(TheTable + BucketNo, false),
                            false); // Already exists in map.

    if (Bucket == getTombstoneVal())
      --NumTombstones;
    Bucket =
        MapEntryTy::Create(KV.first, Allocator, std::move(KV.second));
    ++NumItems;
    assert(NumItems + NumTombstones <= NumBuckets);

    BucketNo = RehashTable(BucketNo);
    return std::make_pair(iterator(TheTable + BucketNo, false), true);
  }

  // clear - Empties out the StringMap
  void clear() {
    if (empty()) return;

    // Zap all values, resetting the keys back to non-present (not tombstone),
    // which is safe because we're removing all elements.
    for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
      StringMapEntryBase *&Bucket = TheTable[I];
      if (Bucket && Bucket != getTombstoneVal()) {
        static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
      }
      Bucket = nullptr;
    }

    NumItems = 0;
    NumTombstones = 0;
  }

  /// remove - Remove the specified key/value pair from the map, but do not
  /// erase it.  This aborts if the key is not in the map.
  void remove(MapEntryTy *KeyValue) {
    RemoveKey(KeyValue);
  }

  void erase(iterator I) {
    MapEntryTy &V = *I;
    remove(&V);
    V.Destroy(Allocator);
  }

  bool erase(StringRef Key) {
    iterator I = find(Key);
    if (I == end()) return false;
    erase(I);
    return true;
  }

  ~StringMap() {
    // Delete all the elements in the map, but don't reset the elements
    // to default values.  This is a copy of clear(), but avoids unnecessary
    // work not required in the destructor.
    if (!empty()) {
      for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
        StringMapEntryBase *Bucket = TheTable[I];
        if (Bucket && Bucket != getTombstoneVal()) {
          static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
        }
      }
    }
    free(TheTable);
  }
};


template<typename ValueTy>
class StringMapConstIterator {
protected:
  StringMapEntryBase **Ptr;
public:
  typedef StringMapEntry<ValueTy> value_type;

  StringMapConstIterator() : Ptr(nullptr) { }

  explicit StringMapConstIterator(StringMapEntryBase **Bucket,
                                  bool NoAdvance = false)
  : Ptr(Bucket) {
    if (!NoAdvance) AdvancePastEmptyBuckets();
  }

  const value_type &operator*() const {
    return *static_cast<StringMapEntry<ValueTy>*>(*Ptr);
  }
  const value_type *operator->() const {
    return static_cast<StringMapEntry<ValueTy>*>(*Ptr);
  }

  bool operator==(const StringMapConstIterator &RHS) const {
    return Ptr == RHS.Ptr;
  }
  bool operator!=(const StringMapConstIterator &RHS) const {
    return Ptr != RHS.Ptr;
  }

  inline StringMapConstIterator& operator++() {   // Preincrement
    ++Ptr;
    AdvancePastEmptyBuckets();
    return *this;
  }
  StringMapConstIterator operator++(int) {        // Postincrement
    StringMapConstIterator tmp = *this; ++*this; return tmp;
  }

private:
  void AdvancePastEmptyBuckets() {
    while (*Ptr == nullptr || *Ptr == StringMapImpl::getTombstoneVal())
      ++Ptr;
  }
};

template<typename ValueTy>
class StringMapIterator : public StringMapConstIterator<ValueTy> {
public:
  StringMapIterator() {}
  explicit StringMapIterator(StringMapEntryBase **Bucket,
                             bool NoAdvance = false)
    : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
  }
  StringMapEntry<ValueTy> &operator*() const {
    return *static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);
  }
  StringMapEntry<ValueTy> *operator->() const {
    return static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);
  }
};

} // namespace llvm

#endif