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 /// StringMapEntryInitializer - This datatype can be partially specialized for
31 /// various datatypes in a stringmap to allow them to be initialized when an
32 /// entry is default constructed for the map.
33 template<typename ValueTy>
34 class StringMapEntryInitializer {
36 template <typename InitTy>
37 static void Initialize(StringMapEntry<ValueTy> &T, InitTy InitVal) {
43 /// StringMapEntryBase - Shared base class of StringMapEntry instances.
44 class StringMapEntryBase {
47 explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}
49 unsigned getKeyLength() const { return StrLen; }
52 /// StringMapImpl - This is the base class of StringMap that is shared among
53 /// all of its instantiations.
56 /// ItemBucket - The hash table consists of an array of these. If Item is
57 /// non-null, this is an extant entry, otherwise, it is a hole.
59 /// FullHashValue - This remembers the full hash value of the key for
61 unsigned FullHashValue;
63 /// Item - This is a pointer to the actual item object.
64 StringMapEntryBase *Item;
71 unsigned NumTombstones;
74 explicit StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
75 // Initialize the map with zero buckets to allocation.
81 StringMapImpl(unsigned InitSize, unsigned ItemSize);
84 /// ShouldRehash - Return true if the table should be rehashed after a new
85 /// element was recently inserted.
86 bool ShouldRehash() const {
87 // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
88 // the buckets are empty (meaning that many are filled with tombstones),
90 return NumItems*4 > NumBuckets*3 ||
91 NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
94 /// LookupBucketFor - Look up the bucket that the specified string should end
95 /// up in. If it already exists as a key in the map, the Item pointer for the
96 /// specified bucket will be non-null. Otherwise, it will be null. In either
97 /// case, the FullHashValue field of the bucket will be set to the hash value
99 unsigned LookupBucketFor(StringRef Key);
101 /// FindKey - Look up the bucket that contains the specified key. If it exists
102 /// in the map, return the bucket number of the key. Otherwise return -1.
103 /// This does not modify the map.
104 int FindKey(StringRef Key) const;
106 /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
107 /// delete it. This aborts if the value isn't in the table.
108 void RemoveKey(StringMapEntryBase *V);
110 /// RemoveKey - Remove the StringMapEntry for the specified key from the
111 /// table, returning it. If the key is not in the table, this returns null.
112 StringMapEntryBase *RemoveKey(StringRef Key);
114 void init(unsigned Size);
116 static StringMapEntryBase *getTombstoneVal() {
117 return (StringMapEntryBase*)-1;
120 unsigned getNumBuckets() const { return NumBuckets; }
121 unsigned getNumItems() const { return NumItems; }
123 bool empty() const { return NumItems == 0; }
124 unsigned size() const { return NumItems; }
127 /// StringMapEntry - This is used to represent one value that is inserted into
128 /// a StringMap. It contains the Value itself and the key: the string length
130 template<typename ValueTy>
131 class StringMapEntry : public StringMapEntryBase {
135 explicit StringMapEntry(unsigned strLen)
136 : StringMapEntryBase(strLen), second() {}
137 StringMapEntry(unsigned strLen, const ValueTy &V)
138 : StringMapEntryBase(strLen), second(V) {}
140 StringRef getKey() const {
141 return StringRef(getKeyData(), getKeyLength());
144 const ValueTy &getValue() const { return second; }
145 ValueTy &getValue() { return second; }
147 void setValue(const ValueTy &V) { second = V; }
149 /// getKeyData - Return the start of the string data that is the key for this
150 /// value. The string data is always stored immediately after the
151 /// StringMapEntry object.
152 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
154 const char *first() const { return getKeyData(); }
156 /// Create - Create a StringMapEntry for the specified key and default
157 /// construct the value.
158 template<typename AllocatorTy, typename InitType>
159 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
160 AllocatorTy &Allocator,
162 unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
164 // Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
165 // in. Allocate a new item with space for the string at the end and a null
168 unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
170 unsigned Alignment = alignOf<StringMapEntry>();
172 StringMapEntry *NewItem =
173 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
175 // Default construct the value.
176 new (NewItem) StringMapEntry(KeyLength);
178 // Copy the string information.
179 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
180 memcpy(StrBuffer, KeyStart, KeyLength);
181 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
183 // Initialize the value if the client wants to.
184 StringMapEntryInitializer<ValueTy>::Initialize(*NewItem, InitVal);
188 template<typename AllocatorTy>
189 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
190 AllocatorTy &Allocator) {
191 return Create(KeyStart, KeyEnd, Allocator, 0);
195 /// Create - Create a StringMapEntry with normal malloc/free.
196 template<typename InitType>
197 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
200 return Create(KeyStart, KeyEnd, A, InitVal);
203 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
204 return Create(KeyStart, KeyEnd, ValueTy());
207 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
208 /// into a StringMapEntry, return the StringMapEntry itself.
209 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
210 StringMapEntry *EPtr = 0;
211 char *Ptr = reinterpret_cast<char*>(&V) -
212 (reinterpret_cast<char*>(&EPtr->second) -
213 reinterpret_cast<char*>(EPtr));
214 return *reinterpret_cast<StringMapEntry*>(Ptr);
216 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
217 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
220 /// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
221 /// into a StringMapEntry, return the StringMapEntry itself.
222 static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
223 char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
224 return *reinterpret_cast<StringMapEntry*>(Ptr);
228 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
229 /// specified allocator.
230 template<typename AllocatorTy>
231 void Destroy(AllocatorTy &Allocator) {
232 // Free memory referenced by the item.
233 this->~StringMapEntry();
234 Allocator.Deallocate(this);
237 /// Destroy this object, releasing memory back to the malloc allocator.
245 /// StringMap - This is an unconventional map that is specialized for handling
246 /// keys that are "strings", which are basically ranges of bytes. This does some
247 /// funky memory allocation and hashing things to make it extremely efficient,
248 /// storing the string data *after* the value in the map.
249 template<typename ValueTy, typename AllocatorTy = MallocAllocator>
250 class StringMap : public StringMapImpl {
251 AllocatorTy Allocator;
252 typedef StringMapEntry<ValueTy> MapEntryTy;
254 StringMap() : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {}
255 explicit StringMap(unsigned InitialSize)
256 : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))) {}
258 explicit StringMap(AllocatorTy A)
259 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))), Allocator(A) {}
261 explicit StringMap(const StringMap &RHS)
262 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
263 assert(RHS.empty() &&
264 "Copy ctor from non-empty stringmap not implemented yet!");
267 void operator=(const StringMap &RHS) {
268 assert(RHS.empty() &&
269 "assignment from non-empty stringmap not implemented yet!");
274 typedef typename ReferenceAdder<AllocatorTy>::result AllocatorRefTy;
275 typedef typename ReferenceAdder<const AllocatorTy>::result AllocatorCRefTy;
276 AllocatorRefTy getAllocator() { return Allocator; }
277 AllocatorCRefTy getAllocator() const { return Allocator; }
279 typedef const char* key_type;
280 typedef ValueTy mapped_type;
281 typedef StringMapEntry<ValueTy> value_type;
282 typedef size_t size_type;
284 typedef StringMapConstIterator<ValueTy> const_iterator;
285 typedef StringMapIterator<ValueTy> iterator;
288 return iterator(TheTable, NumBuckets == 0);
291 return iterator(TheTable+NumBuckets, true);
293 const_iterator begin() const {
294 return const_iterator(TheTable, NumBuckets == 0);
296 const_iterator end() const {
297 return const_iterator(TheTable+NumBuckets, true);
300 iterator find(StringRef Key) {
301 int Bucket = FindKey(Key);
302 if (Bucket == -1) return end();
303 return iterator(TheTable+Bucket);
306 const_iterator find(StringRef Key) const {
307 int Bucket = FindKey(Key);
308 if (Bucket == -1) return end();
309 return const_iterator(TheTable+Bucket);
312 /// lookup - Return the entry for the specified key, or a default
313 /// constructed value if no such entry exists.
314 ValueTy lookup(StringRef Key) const {
315 const_iterator it = find(Key);
321 ValueTy& operator[](StringRef Key) {
322 return GetOrCreateValue(Key).getValue();
325 size_type count(StringRef Key) const {
326 return find(Key) == end() ? 0 : 1;
329 /// insert - Insert the specified key/value pair into the map. If the key
330 /// already exists in the map, return false and ignore the request, otherwise
331 /// insert it and return true.
332 bool insert(MapEntryTy *KeyValue) {
333 unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
334 ItemBucket &Bucket = TheTable[BucketNo];
335 if (Bucket.Item && Bucket.Item != getTombstoneVal())
336 return false; // Already exists in map.
338 if (Bucket.Item == getTombstoneVal())
340 Bucket.Item = KeyValue;
348 // clear - Empties out the StringMap
352 // Zap all values, resetting the keys back to non-present (not tombstone),
353 // which is safe because we're removing all elements.
354 for (ItemBucket *I = TheTable, *E = TheTable+NumBuckets; I != E; ++I) {
355 if (I->Item && I->Item != getTombstoneVal()) {
356 static_cast<MapEntryTy*>(I->Item)->Destroy(Allocator);
364 /// GetOrCreateValue - Look up the specified key in the table. If a value
365 /// exists, return it. Otherwise, default construct a value, insert it, and
367 template <typename InitTy>
368 StringMapEntry<ValueTy> &GetOrCreateValue(StringRef Key,
370 unsigned BucketNo = LookupBucketFor(Key);
371 ItemBucket &Bucket = TheTable[BucketNo];
372 if (Bucket.Item && Bucket.Item != getTombstoneVal())
373 return *static_cast<MapEntryTy*>(Bucket.Item);
375 MapEntryTy *NewItem =
376 MapEntryTy::Create(Key.begin(), Key.end(), Allocator, Val);
378 if (Bucket.Item == getTombstoneVal())
382 // Fill in the bucket for the hash table. The FullHashValue was already
383 // filled in by LookupBucketFor.
384 Bucket.Item = NewItem;
391 StringMapEntry<ValueTy> &GetOrCreateValue(StringRef Key) {
392 return GetOrCreateValue(Key, ValueTy());
395 template <typename InitTy>
396 StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
399 return GetOrCreateValue(StringRef(KeyStart, KeyEnd - KeyStart), Val);
402 StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
403 const char *KeyEnd) {
404 return GetOrCreateValue(StringRef(KeyStart, KeyEnd - KeyStart));
407 /// remove - Remove the specified key/value pair from the map, but do not
408 /// erase it. This aborts if the key is not in the map.
409 void remove(MapEntryTy *KeyValue) {
413 void erase(iterator I) {
416 V.Destroy(Allocator);
419 bool erase(StringRef Key) {
420 iterator I = find(Key);
421 if (I == end()) return false;
433 template<typename ValueTy>
434 class StringMapConstIterator {
436 StringMapImpl::ItemBucket *Ptr;
438 typedef StringMapEntry<ValueTy> value_type;
440 explicit StringMapConstIterator(StringMapImpl::ItemBucket *Bucket,
441 bool NoAdvance = false)
443 if (!NoAdvance) AdvancePastEmptyBuckets();
446 const value_type &operator*() const {
447 return *static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
449 const value_type *operator->() const {
450 return static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
453 bool operator==(const StringMapConstIterator &RHS) const {
454 return Ptr == RHS.Ptr;
456 bool operator!=(const StringMapConstIterator &RHS) const {
457 return Ptr != RHS.Ptr;
460 inline StringMapConstIterator& operator++() { // Preincrement
462 AdvancePastEmptyBuckets();
465 StringMapConstIterator operator++(int) { // Postincrement
466 StringMapConstIterator tmp = *this; ++*this; return tmp;
470 void AdvancePastEmptyBuckets() {
471 while (Ptr->Item == 0 || Ptr->Item == StringMapImpl::getTombstoneVal())
476 template<typename ValueTy>
477 class StringMapIterator : public StringMapConstIterator<ValueTy> {
479 explicit StringMapIterator(StringMapImpl::ItemBucket *Bucket,
480 bool NoAdvance = false)
481 : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
483 StringMapEntry<ValueTy> &operator*() const {
484 return *static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
486 StringMapEntry<ValueTy> *operator->() const {
487 return static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);