1 //===--- StringMap.h - String Hash table map interface ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the StringMap class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ADT_STRINGMAP_H
15 #define LLVM_ADT_STRINGMAP_H
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/Support/Allocator.h"
23 template<typename ValueT>
24 class StringMapConstIterator;
25 template<typename ValueT>
26 class StringMapIterator;
27 template<typename ValueTy>
30 /// StringMapEntryBase - Shared base class of StringMapEntry instances.
31 class StringMapEntryBase {
34 explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}
36 unsigned getKeyLength() const { return StrLen; }
39 /// StringMapImpl - This is the base class of StringMap that is shared among
40 /// all of its instantiations.
43 // Array of NumBuckets pointers to entries, null pointers are holes.
44 // TheTable[NumBuckets] contains a sentinel value for easy iteration. Followed
45 // by an array of the actual hash values as unsigned integers.
46 StringMapEntryBase **TheTable;
49 unsigned NumTombstones;
52 explicit StringMapImpl(unsigned itemSize)
54 // Initialize the map with zero buckets to allocation.
55 NumBuckets(0), NumItems(0), NumTombstones(0), ItemSize(itemSize) {}
56 StringMapImpl(StringMapImpl &&RHS)
57 : TheTable(RHS.TheTable), NumBuckets(RHS.NumBuckets),
58 NumItems(RHS.NumItems), NumTombstones(RHS.NumTombstones),
59 ItemSize(RHS.ItemSize) {
60 RHS.TheTable = nullptr;
63 RHS.NumTombstones = 0;
66 StringMapImpl(unsigned InitSize, unsigned ItemSize);
69 /// LookupBucketFor - Look up the bucket that the specified string should end
70 /// up in. If it already exists as a key in the map, the Item pointer for the
71 /// specified bucket will be non-null. Otherwise, it will be null. In either
72 /// case, the FullHashValue field of the bucket will be set to the hash value
74 unsigned LookupBucketFor(StringRef Key);
76 /// FindKey - Look up the bucket that contains the specified key. If it exists
77 /// in the map, return the bucket number of the key. Otherwise return -1.
78 /// This does not modify the map.
79 int FindKey(StringRef Key) const;
81 /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
82 /// delete it. This aborts if the value isn't in the table.
83 void RemoveKey(StringMapEntryBase *V);
85 /// RemoveKey - Remove the StringMapEntry for the specified key from the
86 /// table, returning it. If the key is not in the table, this returns null.
87 StringMapEntryBase *RemoveKey(StringRef Key);
89 void init(unsigned Size);
91 static StringMapEntryBase *getTombstoneVal() {
92 return (StringMapEntryBase*)-1;
95 unsigned getNumBuckets() const { return NumBuckets; }
96 unsigned getNumItems() const { return NumItems; }
98 bool empty() const { return NumItems == 0; }
99 unsigned size() const { return NumItems; }
101 void swap(StringMapImpl &Other) {
102 std::swap(TheTable, Other.TheTable);
103 std::swap(NumBuckets, Other.NumBuckets);
104 std::swap(NumItems, Other.NumItems);
105 std::swap(NumTombstones, Other.NumTombstones);
109 /// StringMapEntry - This is used to represent one value that is inserted into
110 /// a StringMap. It contains the Value itself and the key: the string length
112 template<typename ValueTy>
113 class StringMapEntry : public StringMapEntryBase {
114 StringMapEntry(StringMapEntry &E) LLVM_DELETED_FUNCTION;
118 explicit StringMapEntry(unsigned strLen)
119 : StringMapEntryBase(strLen), second() {}
120 StringMapEntry(unsigned strLen, ValueTy V)
121 : StringMapEntryBase(strLen), second(std::move(V)) {}
123 StringRef getKey() const {
124 return StringRef(getKeyData(), getKeyLength());
127 const ValueTy &getValue() const { return second; }
128 ValueTy &getValue() { return second; }
130 void setValue(const ValueTy &V) { second = V; }
132 /// getKeyData - Return the start of the string data that is the key for this
133 /// value. The string data is always stored immediately after the
134 /// StringMapEntry object.
135 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
137 StringRef first() const { return StringRef(getKeyData(), getKeyLength()); }
139 /// Create - Create a StringMapEntry for the specified key and default
140 /// construct the value.
141 template<typename AllocatorTy, typename InitType>
142 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
143 AllocatorTy &Allocator,
145 unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
147 // Allocate a new item with space for the string at the end and a null
149 unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
151 unsigned Alignment = alignOf<StringMapEntry>();
153 StringMapEntry *NewItem =
154 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
156 // Default construct the value.
157 new (NewItem) StringMapEntry(KeyLength, std::move(InitVal));
159 // Copy the string information.
160 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
161 memcpy(StrBuffer, KeyStart, KeyLength);
162 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
166 template<typename AllocatorTy>
167 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
168 AllocatorTy &Allocator) {
169 return Create(KeyStart, KeyEnd, Allocator, 0);
172 /// Create - Create a StringMapEntry with normal malloc/free.
173 template<typename InitType>
174 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
177 return Create(KeyStart, KeyEnd, A, std::move(InitVal));
180 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
181 return Create(KeyStart, KeyEnd, ValueTy());
184 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
185 /// into a StringMapEntry, return the StringMapEntry itself.
186 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
187 StringMapEntry *EPtr = 0;
188 char *Ptr = reinterpret_cast<char*>(&V) -
189 (reinterpret_cast<char*>(&EPtr->second) -
190 reinterpret_cast<char*>(EPtr));
191 return *reinterpret_cast<StringMapEntry*>(Ptr);
193 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
194 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
197 /// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
198 /// into a StringMapEntry, return the StringMapEntry itself.
199 static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
200 char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
201 return *reinterpret_cast<StringMapEntry*>(Ptr);
204 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
205 /// specified allocator.
206 template<typename AllocatorTy>
207 void Destroy(AllocatorTy &Allocator) {
208 // Free memory referenced by the item.
210 static_cast<unsigned>(sizeof(StringMapEntry)) + getKeyLength() + 1;
211 this->~StringMapEntry();
212 Allocator.Deallocate(static_cast<void *>(this), AllocSize);
215 /// Destroy this object, releasing memory back to the malloc allocator.
223 /// StringMap - This is an unconventional map that is specialized for handling
224 /// keys that are "strings", which are basically ranges of bytes. This does some
225 /// funky memory allocation and hashing things to make it extremely efficient,
226 /// storing the string data *after* the value in the map.
227 template<typename ValueTy, typename AllocatorTy = MallocAllocator>
228 class StringMap : public StringMapImpl {
229 AllocatorTy Allocator;
231 typedef StringMapEntry<ValueTy> MapEntryTy;
233 StringMap() : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {}
234 explicit StringMap(unsigned InitialSize)
235 : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))) {}
237 explicit StringMap(AllocatorTy A)
238 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))), Allocator(A) {}
240 StringMap(unsigned InitialSize, AllocatorTy A)
241 : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))),
244 StringMap(StringMap &&RHS)
245 : StringMapImpl(std::move(RHS)), Allocator(std::move(RHS.Allocator)) {}
247 StringMap &operator=(StringMap RHS) {
248 StringMapImpl::swap(RHS);
249 std::swap(Allocator, RHS.Allocator);
253 // FIXME: Implement copy operations if/when they're needed.
255 AllocatorTy &getAllocator() { return Allocator; }
256 const AllocatorTy &getAllocator() const { return Allocator; }
258 typedef const char* key_type;
259 typedef ValueTy mapped_type;
260 typedef StringMapEntry<ValueTy> value_type;
261 typedef size_t size_type;
263 typedef StringMapConstIterator<ValueTy> const_iterator;
264 typedef StringMapIterator<ValueTy> iterator;
267 return iterator(TheTable, NumBuckets == 0);
270 return iterator(TheTable+NumBuckets, true);
272 const_iterator begin() const {
273 return const_iterator(TheTable, NumBuckets == 0);
275 const_iterator end() const {
276 return const_iterator(TheTable+NumBuckets, true);
279 iterator find(StringRef Key) {
280 int Bucket = FindKey(Key);
281 if (Bucket == -1) return end();
282 return iterator(TheTable+Bucket, true);
285 const_iterator find(StringRef Key) const {
286 int Bucket = FindKey(Key);
287 if (Bucket == -1) return end();
288 return const_iterator(TheTable+Bucket, true);
291 /// lookup - Return the entry for the specified key, or a default
292 /// constructed value if no such entry exists.
293 ValueTy lookup(StringRef Key) const {
294 const_iterator it = find(Key);
300 ValueTy &operator[](StringRef Key) {
301 return GetOrCreateValue(Key).getValue();
304 /// count - Return 1 if the element is in the map, 0 otherwise.
305 size_type count(StringRef Key) const {
306 return find(Key) == end() ? 0 : 1;
309 /// insert - Insert the specified key/value pair into the map. If the key
310 /// already exists in the map, return false and ignore the request, otherwise
311 /// insert it and return true.
312 bool insert(MapEntryTy *KeyValue) {
313 unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
314 StringMapEntryBase *&Bucket = TheTable[BucketNo];
315 if (Bucket && Bucket != getTombstoneVal())
316 return false; // Already exists in map.
318 if (Bucket == getTombstoneVal())
322 assert(NumItems + NumTombstones <= NumBuckets);
328 // clear - Empties out the StringMap
332 // Zap all values, resetting the keys back to non-present (not tombstone),
333 // which is safe because we're removing all elements.
334 for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
335 StringMapEntryBase *&Bucket = TheTable[I];
336 if (Bucket && Bucket != getTombstoneVal()) {
337 static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
346 /// GetOrCreateValue - Look up the specified key in the table. If a value
347 /// exists, return it. Otherwise, default construct a value, insert it, and
349 template <typename InitTy>
350 MapEntryTy &GetOrCreateValue(StringRef Key, InitTy Val) {
351 unsigned BucketNo = LookupBucketFor(Key);
352 StringMapEntryBase *&Bucket = TheTable[BucketNo];
353 if (Bucket && Bucket != getTombstoneVal())
354 return *static_cast<MapEntryTy*>(Bucket);
356 MapEntryTy *NewItem =
357 MapEntryTy::Create(Key.begin(), Key.end(), Allocator, std::move(Val));
359 if (Bucket == getTombstoneVal())
362 assert(NumItems + NumTombstones <= NumBuckets);
364 // Fill in the bucket for the hash table. The FullHashValue was already
365 // filled in by LookupBucketFor.
372 MapEntryTy &GetOrCreateValue(StringRef Key) {
373 return GetOrCreateValue(Key, ValueTy());
376 /// remove - Remove the specified key/value pair from the map, but do not
377 /// erase it. This aborts if the key is not in the map.
378 void remove(MapEntryTy *KeyValue) {
382 void erase(iterator I) {
385 V.Destroy(Allocator);
388 bool erase(StringRef Key) {
389 iterator I = find(Key);
390 if (I == end()) return false;
396 // Delete all the elements in the map, but don't reset the elements
397 // to default values. This is a copy of clear(), but avoids unnecessary
398 // work not required in the destructor.
400 for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
401 StringMapEntryBase *Bucket = TheTable[I];
402 if (Bucket && Bucket != getTombstoneVal()) {
403 static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
412 template<typename ValueTy>
413 class StringMapConstIterator {
415 StringMapEntryBase **Ptr;
417 typedef StringMapEntry<ValueTy> value_type;
419 StringMapConstIterator() : Ptr(nullptr) { }
421 explicit StringMapConstIterator(StringMapEntryBase **Bucket,
422 bool NoAdvance = false)
424 if (!NoAdvance) AdvancePastEmptyBuckets();
427 const value_type &operator*() const {
428 return *static_cast<StringMapEntry<ValueTy>*>(*Ptr);
430 const value_type *operator->() const {
431 return static_cast<StringMapEntry<ValueTy>*>(*Ptr);
434 bool operator==(const StringMapConstIterator &RHS) const {
435 return Ptr == RHS.Ptr;
437 bool operator!=(const StringMapConstIterator &RHS) const {
438 return Ptr != RHS.Ptr;
441 inline StringMapConstIterator& operator++() { // Preincrement
443 AdvancePastEmptyBuckets();
446 StringMapConstIterator operator++(int) { // Postincrement
447 StringMapConstIterator tmp = *this; ++*this; return tmp;
451 void AdvancePastEmptyBuckets() {
452 while (*Ptr == nullptr || *Ptr == StringMapImpl::getTombstoneVal())
457 template<typename ValueTy>
458 class StringMapIterator : public StringMapConstIterator<ValueTy> {
460 StringMapIterator() {}
461 explicit StringMapIterator(StringMapEntryBase **Bucket,
462 bool NoAdvance = false)
463 : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
465 StringMapEntry<ValueTy> &operator*() const {
466 return *static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);
468 StringMapEntry<ValueTy> *operator->() const {
469 return static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);