1 //===--- StringMap.h - String Hash table map interface ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Chris Lattner and is distributed under
6 // the University of Illinois Open Source 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"
21 template<typename ValueT>
22 class StringMapConstIterator;
23 template<typename ValueT>
24 class StringMapIterator;
27 /// StringMapEntryBase - Shared base class of StringMapEntry instances.
28 class StringMapEntryBase {
31 StringMapEntryBase(unsigned Len) : StrLen(Len) {}
33 unsigned getKeyLength() const { return StrLen; }
36 /// StringMapImpl - This is the base class of StringMap that is shared among
37 /// all of its instantiations.
40 /// ItemBucket - The hash table consists of an array of these. If Item is
41 /// non-null, this is an extant entry, otherwise, it is a hole.
43 /// FullHashValue - This remembers the full hash value of the key for
45 unsigned FullHashValue;
47 /// Item - This is a pointer to the actual item object.
48 StringMapEntryBase *Item;
55 unsigned NumTombstones;
58 StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
59 // Initialize the map with zero buckets to allocation.
65 StringMapImpl(unsigned InitSize, unsigned ItemSize);
68 /// ShouldRehash - Return true if the table should be rehashed after a new
69 /// element was recently inserted.
70 bool ShouldRehash() const {
71 // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
72 // the buckets are empty (meaning that many are filled with tombstones),
74 return NumItems*4 > NumBuckets*3 ||
75 NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
78 /// LookupBucketFor - Look up the bucket that the specified string should end
79 /// up in. If it already exists as a key in the map, the Item pointer for the
80 /// specified bucket will be non-null. Otherwise, it will be null. In either
81 /// case, the FullHashValue field of the bucket will be set to the hash value
83 unsigned LookupBucketFor(const char *KeyStart, const char *KeyEnd);
85 /// FindKey - Look up the bucket that contains the specified key. If it exists
86 /// in the map, return the bucket number of the key. Otherwise return -1.
87 /// This does not modify the map.
88 int FindKey(const char *KeyStart, const char *KeyEnd) const;
90 /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
91 /// delete it. This aborts if the value isn't in the table.
92 void RemoveKey(StringMapEntryBase *V);
94 /// RemoveKey - Remove the StringMapEntry for the specified key from the
95 /// table, returning it. If the key is not in the table, this returns null.
96 StringMapEntryBase *RemoveKey(const char *KeyStart, const char *KeyEnd);
98 void init(unsigned Size);
100 static StringMapEntryBase *getTombstoneVal() {
101 return (StringMapEntryBase*)-1;
104 unsigned getNumBuckets() const { return NumBuckets; }
105 unsigned getNumItems() const { return NumItems; }
107 bool empty() const { return NumItems == 0; }
108 unsigned size() const { return NumItems; }
111 /// StringMapEntry - This is used to represent one value that is inserted into
112 /// a StringMap. It contains the Value itself and the key: the string length
114 template<typename ValueTy>
115 class StringMapEntry : public StringMapEntryBase {
118 StringMapEntry(unsigned StrLen)
119 : StringMapEntryBase(StrLen), Val() {}
120 StringMapEntry(unsigned StrLen, const ValueTy &V)
121 : StringMapEntryBase(StrLen), Val(V) {}
123 const ValueTy &getValue() const { return Val; }
124 ValueTy &getValue() { return Val; }
126 void setValue(const ValueTy &V) { Val = V; }
128 /// getKeyData - Return the start of the string data that is the key for this
129 /// value. The string data is always stored immediately after the
130 /// StringMapEntry object.
131 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
133 /// Create - Create a StringMapEntry for the specified key and default
134 /// construct the value.
135 template<typename AllocatorTy>
136 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
137 AllocatorTy &Allocator) {
138 unsigned KeyLength = KeyEnd-KeyStart;
140 // Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
141 // in. Allocate a new item with space for the string at the end and a null
143 unsigned AllocSize = sizeof(StringMapEntry)+KeyLength+1;
146 unsigned Alignment = __alignof__(StringMapEntry);
149 unsigned Alignment = 8;
151 StringMapEntry *NewItem =
152 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize, Alignment));
154 // Default construct the value.
155 new (NewItem) StringMapEntry(KeyLength);
157 // Copy the string information.
158 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
159 memcpy(StrBuffer, KeyStart, KeyLength);
160 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
164 /// Create - Create a StringMapEntry with normal malloc/free.
165 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
167 return Create(KeyStart, KeyEnd, A);
171 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
172 /// into a StringMapEntry, return the StringMapEntry itself.
173 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
174 return *reinterpret_cast<StringMapEntry*>(reinterpret_cast<char*>(&V) -
175 sizeof(StringMapEntryBase));
177 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
178 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
181 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
182 /// specified allocator.
183 template<typename AllocatorTy>
184 void Destroy(AllocatorTy &Allocator) {
185 // Free memory referenced by the item.
186 this->~StringMapEntry();
187 Allocator.Deallocate(this);
190 /// Destroy this object, releasing memory back to the malloc allocator.
198 /// StringMap - This is an unconventional map that is specialized for handling
199 /// keys that are "strings", which are basically ranges of bytes. This does some
200 /// funky memory allocation and hashing things to make it extremely efficient,
201 /// storing the string data *after* the value in the map.
202 template<typename ValueTy, typename AllocatorTy = MallocAllocator>
203 class StringMap : public StringMapImpl {
204 AllocatorTy Allocator;
205 typedef StringMapEntry<ValueTy> MapEntryTy;
207 StringMap() : StringMapImpl(sizeof(MapEntryTy)) {}
208 StringMap(unsigned InitialSize)
209 : StringMapImpl(InitialSize, sizeof(MapEntryTy)) {}
211 AllocatorTy &getAllocator() { return Allocator; }
212 const AllocatorTy &getAllocator() const { return Allocator; }
214 typedef StringMapConstIterator<ValueTy> const_iterator;
215 typedef StringMapIterator<ValueTy> iterator;
218 return iterator(TheTable, NumBuckets == 0);
221 return iterator(TheTable+NumBuckets, true);
223 const_iterator begin() const {
224 return const_iterator(TheTable, NumBuckets == 0);
226 const_iterator end() const {
227 return const_iterator(TheTable+NumBuckets, true);
230 iterator find(const char *KeyStart, const char *KeyEnd) {
231 int Bucket = FindKey(KeyStart, KeyEnd);
232 if (Bucket == -1) return end();
233 return iterator(TheTable+Bucket);
236 const_iterator find(const char *KeyStart, const char *KeyEnd) const {
237 int Bucket = FindKey(KeyStart, KeyEnd);
238 if (Bucket == -1) return end();
239 return const_iterator(TheTable+Bucket);
242 /// insert - Insert the specified key/value pair into the map. If the key
243 /// already exists in the map, return false and ignore the request, otherwise
244 /// insert it and return true.
245 bool insert(MapEntryTy *KeyValue) {
247 LookupBucketFor(KeyValue->getKeyData(),
248 KeyValue->getKeyData()+KeyValue->getKeyLength());
249 ItemBucket &Bucket = TheTable[BucketNo];
250 if (Bucket.Item && Bucket.Item != getTombstoneVal())
251 return false; // Already exists in map.
253 if (Bucket.Item == getTombstoneVal())
255 Bucket.Item = KeyValue;
263 /// GetOrCreateValue - Look up the specified key in the table. If a value
264 /// exists, return it. Otherwise, default construct a value, insert it, and
266 StringMapEntry<ValueTy> &GetOrCreateValue(const char *KeyStart,
267 const char *KeyEnd) {
268 unsigned BucketNo = LookupBucketFor(KeyStart, KeyEnd);
269 ItemBucket &Bucket = TheTable[BucketNo];
270 if (Bucket.Item && Bucket.Item != getTombstoneVal())
271 return *static_cast<MapEntryTy*>(Bucket.Item);
273 MapEntryTy *NewItem = MapEntryTy::Create(KeyStart, KeyEnd, Allocator);
275 if (Bucket.Item == getTombstoneVal())
279 // Fill in the bucket for the hash table. The FullHashValue was already
280 // filled in by LookupBucketFor.
281 Bucket.Item = NewItem;
288 /// remove - Remove the specified key/value pair from the map, but do not
289 /// erase it. This aborts if the key is not in the map.
290 void remove(MapEntryTy *KeyValue) {
294 void erase(iterator I) {
297 V.Destroy(Allocator);
301 for (ItemBucket *I = TheTable, *E = TheTable+NumBuckets; I != E; ++I) {
302 if (I->Item && I->Item != getTombstoneVal())
303 static_cast<MapEntryTy*>(I->Item)->Destroy(Allocator);
308 StringMap(const StringMap &); // FIXME: Implement.
309 void operator=(const StringMap &); // FIXME: Implement.
313 template<typename ValueTy>
314 class StringMapConstIterator {
316 StringMapImpl::ItemBucket *Ptr;
318 StringMapConstIterator(StringMapImpl::ItemBucket *Bucket,
319 bool NoAdvance = false)
321 if (!NoAdvance) AdvancePastEmptyBuckets();
324 const StringMapEntry<ValueTy> &operator*() const {
325 return *static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
327 const StringMapEntry<ValueTy> *operator->() const {
328 return static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
331 bool operator==(const StringMapConstIterator &RHS) const {
332 return Ptr == RHS.Ptr;
334 bool operator!=(const StringMapConstIterator &RHS) const {
335 return Ptr != RHS.Ptr;
338 inline StringMapConstIterator& operator++() { // Preincrement
340 AdvancePastEmptyBuckets();
343 StringMapConstIterator operator++(int) { // Postincrement
344 StringMapConstIterator tmp = *this; ++*this; return tmp;
348 void AdvancePastEmptyBuckets() {
349 while (Ptr->Item == 0 || Ptr->Item == StringMapImpl::getTombstoneVal())
354 template<typename ValueTy>
355 class StringMapIterator : public StringMapConstIterator<ValueTy> {
357 StringMapIterator(StringMapImpl::ItemBucket *Bucket,
358 bool NoAdvance = false)
359 : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
361 StringMapEntry<ValueTy> &operator*() const {
362 return *static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
364 StringMapEntry<ValueTy> *operator->() const {
365 return static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);