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/Support/Allocator.h"
22 template<typename ValueT>
23 class StringMapConstIterator;
24 template<typename ValueT>
25 class StringMapIterator;
26 template<typename ValueTy>
29 /// StringMapEntryInitializer - This datatype can be partially specialized for
30 /// various datatypes in a stringmap to allow them to be initialized when an
31 /// entry is default constructed for the map.
32 template<typename ValueTy>
33 class StringMapEntryInitializer {
35 template <typename InitTy>
36 static void Initialize(StringMapEntry<ValueTy> &T, InitTy InitVal) {
41 /// StringMapEntryBase - Shared base class of StringMapEntry instances.
42 class StringMapEntryBase {
45 explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}
47 unsigned getKeyLength() const { return StrLen; }
50 /// StringMapImpl - This is the base class of StringMap that is shared among
51 /// all of its instantiations.
54 /// ItemBucket - The hash table consists of an array of these. If Item is
55 /// non-null, this is an extant entry, otherwise, it is a hole.
57 /// FullHashValue - This remembers the full hash value of the key for
59 unsigned FullHashValue;
61 /// Item - This is a pointer to the actual item object.
62 StringMapEntryBase *Item;
69 unsigned NumTombstones;
72 explicit StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
73 // Initialize the map with zero buckets to allocation.
79 StringMapImpl(unsigned InitSize, unsigned ItemSize);
82 /// ShouldRehash - Return true if the table should be rehashed after a new
83 /// element was recently inserted.
84 bool ShouldRehash() const {
85 // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
86 // the buckets are empty (meaning that many are filled with tombstones),
88 return NumItems*4 > NumBuckets*3 ||
89 NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
92 /// LookupBucketFor - Look up the bucket that the specified string should end
93 /// up in. If it already exists as a key in the map, the Item pointer for the
94 /// specified bucket will be non-null. Otherwise, it will be null. In either
95 /// case, the FullHashValue field of the bucket will be set to the hash value
97 unsigned LookupBucketFor(const char *KeyStart, const char *KeyEnd);
99 /// FindKey - Look up the bucket that contains the specified key. If it exists
100 /// in the map, return the bucket number of the key. Otherwise return -1.
101 /// This does not modify the map.
102 int FindKey(const char *KeyStart, const char *KeyEnd) const;
104 /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
105 /// delete it. This aborts if the value isn't in the table.
106 void RemoveKey(StringMapEntryBase *V);
108 /// RemoveKey - Remove the StringMapEntry for the specified key from the
109 /// table, returning it. If the key is not in the table, this returns null.
110 StringMapEntryBase *RemoveKey(const char *KeyStart, const char *KeyEnd);
112 void init(unsigned Size);
114 static StringMapEntryBase *getTombstoneVal() {
115 return (StringMapEntryBase*)-1;
118 unsigned getNumBuckets() const { return NumBuckets; }
119 unsigned getNumItems() const { return NumItems; }
121 bool empty() const { return NumItems == 0; }
122 unsigned size() const { return NumItems; }
125 /// StringMapEntry - This is used to represent one value that is inserted into
126 /// a StringMap. It contains the Value itself and the key: the string length
128 template<typename ValueTy>
129 class StringMapEntry : public StringMapEntryBase {
133 explicit StringMapEntry(unsigned strLen)
134 : StringMapEntryBase(strLen), second() {}
135 StringMapEntry(unsigned strLen, const ValueTy &V)
136 : StringMapEntryBase(strLen), second(V) {}
138 const ValueTy &getValue() const { return second; }
139 ValueTy &getValue() { return second; }
141 void setValue(const ValueTy &V) { second = V; }
143 /// getKeyData - Return the start of the string data that is the key for this
144 /// value. The string data is always stored immediately after the
145 /// StringMapEntry object.
146 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
148 const char *first() const { return getKeyData(); }
150 /// Create - Create a StringMapEntry for the specified key and default
151 /// construct the value.
152 template<typename AllocatorTy, typename InitType>
153 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
154 AllocatorTy &Allocator,
156 unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
158 // Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
159 // in. Allocate a new item with space for the string at the end and a null
162 unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
164 unsigned Alignment = alignof<StringMapEntry>();
166 StringMapEntry *NewItem =
167 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
169 // Default construct the value.
170 new (NewItem) StringMapEntry(KeyLength);
172 // Copy the string information.
173 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
174 memcpy(StrBuffer, KeyStart, KeyLength);
175 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
177 // Initialize the value if the client wants to.
178 StringMapEntryInitializer<ValueTy>::Initialize(*NewItem, InitVal);
182 template<typename AllocatorTy>
183 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
184 AllocatorTy &Allocator) {
185 return Create(KeyStart, KeyEnd, Allocator, (void*)0);
189 /// Create - Create a StringMapEntry with normal malloc/free.
190 template<typename InitType>
191 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
194 return Create(KeyStart, KeyEnd, A, InitVal);
197 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
198 return Create(KeyStart, KeyEnd, (void*)0);
201 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
202 /// into a StringMapEntry, return the StringMapEntry itself.
203 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
204 StringMapEntry *EPtr = 0;
205 char *Ptr = reinterpret_cast<char*>(&V) -
206 (reinterpret_cast<char*>(&EPtr->second) -
207 reinterpret_cast<char*>(EPtr));
208 return *reinterpret_cast<StringMapEntry*>(Ptr);
210 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
211 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
214 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
215 /// specified allocator.
216 template<typename AllocatorTy>
217 void Destroy(AllocatorTy &Allocator) {
218 // Free memory referenced by the item.
219 this->~StringMapEntry();
220 Allocator.Deallocate(this);
223 /// Destroy this object, releasing memory back to the malloc allocator.
231 /// StringMap - This is an unconventional map that is specialized for handling
232 /// keys that are "strings", which are basically ranges of bytes. This does some
233 /// funky memory allocation and hashing things to make it extremely efficient,
234 /// storing the string data *after* the value in the map.
235 template<typename ValueTy, typename AllocatorTy = MallocAllocator>
236 class StringMap : public StringMapImpl {
237 AllocatorTy Allocator;
238 typedef StringMapEntry<ValueTy> MapEntryTy;
240 StringMap() : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {}
241 explicit StringMap(unsigned InitialSize)
242 : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))) {}
244 AllocatorTy &getAllocator() { return Allocator; }
245 const AllocatorTy &getAllocator() const { return Allocator; }
247 typedef const char* key_type;
248 typedef ValueTy mapped_type;
249 typedef StringMapEntry<ValueTy> value_type;
250 typedef size_t size_type;
252 typedef StringMapConstIterator<ValueTy> const_iterator;
253 typedef StringMapIterator<ValueTy> iterator;
256 return iterator(TheTable, NumBuckets == 0);
259 return iterator(TheTable+NumBuckets, true);
261 const_iterator begin() const {
262 return const_iterator(TheTable, NumBuckets == 0);
264 const_iterator end() const {
265 return const_iterator(TheTable+NumBuckets, true);
268 iterator find(const char *KeyStart, const char *KeyEnd) {
269 int Bucket = FindKey(KeyStart, KeyEnd);
270 if (Bucket == -1) return end();
271 return iterator(TheTable+Bucket);
273 iterator find(const char *Key) {
274 return find(Key, Key + strlen(Key));
276 iterator find(const std::string &Key) {
277 const char* key_start = (Key.empty() ? NULL : &Key[0]);
278 return find(key_start, key_start + Key.size());
281 const_iterator find(const char *KeyStart, const char *KeyEnd) const {
282 int Bucket = FindKey(KeyStart, KeyEnd);
283 if (Bucket == -1) return end();
284 return const_iterator(TheTable+Bucket);
286 const_iterator find(const char *Key) const {
287 return find(Key, Key + strlen(Key));
289 const_iterator find(const std::string &Key) const {
290 const char* key_start = (Key.empty() ? NULL : &Key[0]);
291 return find(key_start, key_start + Key.size());
294 ValueTy& operator[](const char *Key) {
295 value_type& entry = GetOrCreateValue(Key, Key + strlen(Key));
296 return entry.getValue();
298 ValueTy& operator[](const std::string &Key) {
299 const char* key_start = (Key.empty() ? NULL : &Key[0]);
300 value_type& entry = GetOrCreateValue(key_start, key_start + Key.size());
301 return entry.getValue();
304 size_type count(const char *KeyStart, const char *KeyEnd) const {
305 return find(KeyStart, KeyEnd) == end() ? 0 : 1;
307 size_type count(const char *Key) const {
308 return count(Key, Key + strlen(Key));
310 size_type count(const std::string &Key) const {
311 const char* key_start = (Key.empty() ? NULL : &Key[0]);
312 return count(key_start, key_start + Key.size());
315 /// insert - Insert the specified key/value pair into the map. If the key
316 /// already exists in the map, return false and ignore the request, otherwise
317 /// insert it and return true.
318 bool insert(MapEntryTy *KeyValue) {
320 LookupBucketFor(KeyValue->getKeyData(),
321 KeyValue->getKeyData()+KeyValue->getKeyLength());
322 ItemBucket &Bucket = TheTable[BucketNo];
323 if (Bucket.Item && Bucket.Item != getTombstoneVal())
324 return false; // Already exists in map.
326 if (Bucket.Item == getTombstoneVal())
328 Bucket.Item = KeyValue;
336 // clear - Empties out the StringMap
340 // Zap all values, resetting the keys back to non-present (not tombstone),
341 // which is safe because we're removing all elements.
342 for (ItemBucket *I = TheTable, *E = TheTable+NumBuckets; I != E; ++I) {
343 if (I->Item && I->Item != getTombstoneVal()) {
344 static_cast<MapEntryTy*>(I->Item)->Destroy(Allocator);
350 /// GetOrCreateValue - Look up the specified key in the table. If a value
351 /// exists, return it. Otherwise, default construct a value, insert it, and
353 template <typename InitTy>
354 StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
357 unsigned BucketNo = LookupBucketFor(KeyStart, KeyEnd);
358 ItemBucket &Bucket = TheTable[BucketNo];
359 if (Bucket.Item && Bucket.Item != getTombstoneVal())
360 return *static_cast<MapEntryTy*>(Bucket.Item);
362 MapEntryTy *NewItem = MapEntryTy::Create(KeyStart, KeyEnd, Allocator, Val);
364 if (Bucket.Item == getTombstoneVal())
368 // Fill in the bucket for the hash table. The FullHashValue was already
369 // filled in by LookupBucketFor.
370 Bucket.Item = NewItem;
377 StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
378 const char *KeyEnd) {
379 return GetOrCreateValue(KeyStart, KeyEnd, (void*)0);
382 /// remove - Remove the specified key/value pair from the map, but do not
383 /// erase it. This aborts if the key is not in the map.
384 void remove(MapEntryTy *KeyValue) {
388 void erase(iterator I) {
391 V.Destroy(Allocator);
394 bool erase(const char *Key) {
395 iterator I = find(Key);
396 if (I == end()) return false;
401 bool erase(const std::string &Key) {
402 iterator I = find(Key);
403 if (I == end()) return false;
413 StringMap(const StringMap &); // FIXME: Implement.
414 void operator=(const StringMap &); // FIXME: Implement.
418 template<typename ValueTy>
419 class StringMapConstIterator {
421 StringMapImpl::ItemBucket *Ptr;
423 explicit StringMapConstIterator(StringMapImpl::ItemBucket *Bucket,
424 bool NoAdvance = false)
426 if (!NoAdvance) AdvancePastEmptyBuckets();
429 const StringMapEntry<ValueTy> &operator*() const {
430 return *static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
432 const StringMapEntry<ValueTy> *operator->() const {
433 return static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
436 bool operator==(const StringMapConstIterator &RHS) const {
437 return Ptr == RHS.Ptr;
439 bool operator!=(const StringMapConstIterator &RHS) const {
440 return Ptr != RHS.Ptr;
443 inline StringMapConstIterator& operator++() { // Preincrement
445 AdvancePastEmptyBuckets();
448 StringMapConstIterator operator++(int) { // Postincrement
449 StringMapConstIterator tmp = *this; ++*this; return tmp;
453 void AdvancePastEmptyBuckets() {
454 while (Ptr->Item == 0 || Ptr->Item == StringMapImpl::getTombstoneVal())
459 template<typename ValueTy>
460 class StringMapIterator : public StringMapConstIterator<ValueTy> {
462 explicit StringMapIterator(StringMapImpl::ItemBucket *Bucket,
463 bool NoAdvance = false)
464 : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
466 StringMapEntry<ValueTy> &operator*() const {
467 return *static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
469 StringMapEntry<ValueTy> *operator->() const {
470 return static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);