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"
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) {
42 /// StringMapEntryBase - Shared base class of StringMapEntry instances.
43 class StringMapEntryBase {
46 explicit StringMapEntryBase(unsigned Len) : StrLen(Len) {}
48 unsigned getKeyLength() const { return StrLen; }
51 /// StringMapImpl - This is the base class of StringMap that is shared among
52 /// all of its instantiations.
55 // Array of NumBuckets pointers to entries, null pointers are holes.
56 // TheTable[NumBuckets] contains a sentinel value for easy iteration. Followed
57 // by an array of the actual hash values as unsigned integers.
58 StringMapEntryBase **TheTable;
61 unsigned NumTombstones;
64 explicit StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
65 // Initialize the map with zero buckets to allocation.
71 StringMapImpl(unsigned InitSize, unsigned ItemSize);
74 /// LookupBucketFor - Look up the bucket that the specified string should end
75 /// up in. If it already exists as a key in the map, the Item pointer for the
76 /// specified bucket will be non-null. Otherwise, it will be null. In either
77 /// case, the FullHashValue field of the bucket will be set to the hash value
79 unsigned LookupBucketFor(StringRef Key);
81 /// FindKey - Look up the bucket that contains the specified key. If it exists
82 /// in the map, return the bucket number of the key. Otherwise return -1.
83 /// This does not modify the map.
84 int FindKey(StringRef Key) const;
86 /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
87 /// delete it. This aborts if the value isn't in the table.
88 void RemoveKey(StringMapEntryBase *V);
90 /// RemoveKey - Remove the StringMapEntry for the specified key from the
91 /// table, returning it. If the key is not in the table, this returns null.
92 StringMapEntryBase *RemoveKey(StringRef Key);
94 void init(unsigned Size);
96 static StringMapEntryBase *getTombstoneVal() {
97 return (StringMapEntryBase*)-1;
100 unsigned getNumBuckets() const { return NumBuckets; }
101 unsigned getNumItems() const { return NumItems; }
103 bool empty() const { return NumItems == 0; }
104 unsigned size() const { return NumItems; }
106 void swap(StringMapImpl &Other) {
107 std::swap(TheTable, Other.TheTable);
108 std::swap(NumBuckets, Other.NumBuckets);
109 std::swap(NumItems, Other.NumItems);
110 std::swap(NumTombstones, Other.NumTombstones);
114 /// StringMapEntry - This is used to represent one value that is inserted into
115 /// a StringMap. It contains the Value itself and the key: the string length
117 template<typename ValueTy>
118 class StringMapEntry : public StringMapEntryBase {
122 explicit StringMapEntry(unsigned strLen)
123 : StringMapEntryBase(strLen), second() {}
124 StringMapEntry(unsigned strLen, const ValueTy &V)
125 : StringMapEntryBase(strLen), second(V) {}
127 StringRef getKey() const {
128 return StringRef(getKeyData(), getKeyLength());
131 const ValueTy &getValue() const { return second; }
132 ValueTy &getValue() { return second; }
134 void setValue(const ValueTy &V) { second = V; }
136 /// getKeyData - Return the start of the string data that is the key for this
137 /// value. The string data is always stored immediately after the
138 /// StringMapEntry object.
139 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
141 StringRef first() const { return StringRef(getKeyData(), getKeyLength()); }
143 /// Create - Create a StringMapEntry for the specified key and default
144 /// construct the value.
145 template<typename AllocatorTy, typename InitType>
146 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
147 AllocatorTy &Allocator,
149 unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
151 // Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
152 // in. Allocate a new item with space for the string at the end and a null
155 unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
157 unsigned Alignment = alignOf<StringMapEntry>();
159 StringMapEntry *NewItem =
160 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
162 // Default construct the value.
163 new (NewItem) StringMapEntry(KeyLength);
165 // Copy the string information.
166 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
167 memcpy(StrBuffer, KeyStart, KeyLength);
168 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
170 // Initialize the value if the client wants to.
171 StringMapEntryInitializer<ValueTy>::Initialize(*NewItem, InitVal);
175 template<typename AllocatorTy>
176 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
177 AllocatorTy &Allocator) {
178 return Create(KeyStart, KeyEnd, Allocator, 0);
181 /// Create - Create a StringMapEntry with normal malloc/free.
182 template<typename InitType>
183 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
186 return Create(KeyStart, KeyEnd, A, InitVal);
189 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
190 return Create(KeyStart, KeyEnd, ValueTy());
193 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
194 /// into a StringMapEntry, return the StringMapEntry itself.
195 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
196 StringMapEntry *EPtr = 0;
197 char *Ptr = reinterpret_cast<char*>(&V) -
198 (reinterpret_cast<char*>(&EPtr->second) -
199 reinterpret_cast<char*>(EPtr));
200 return *reinterpret_cast<StringMapEntry*>(Ptr);
202 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
203 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
206 /// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
207 /// into a StringMapEntry, return the StringMapEntry itself.
208 static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
209 char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
210 return *reinterpret_cast<StringMapEntry*>(Ptr);
213 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
214 /// specified allocator.
215 template<typename AllocatorTy>
216 void Destroy(AllocatorTy &Allocator) {
217 // Free memory referenced by the item.
218 this->~StringMapEntry();
219 Allocator.Deallocate(this);
222 /// Destroy this object, releasing memory back to the malloc allocator.
230 /// StringMap - This is an unconventional map that is specialized for handling
231 /// keys that are "strings", which are basically ranges of bytes. This does some
232 /// funky memory allocation and hashing things to make it extremely efficient,
233 /// storing the string data *after* the value in the map.
234 template<typename ValueTy, typename AllocatorTy = MallocAllocator>
235 class StringMap : public StringMapImpl {
236 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 explicit StringMap(AllocatorTy A)
245 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))), Allocator(A) {}
247 StringMap(unsigned InitialSize, AllocatorTy A)
248 : StringMapImpl(InitialSize, static_cast<unsigned>(sizeof(MapEntryTy))),
251 StringMap(const StringMap &RHS)
252 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
253 assert(RHS.empty() &&
254 "Copy ctor from non-empty stringmap not implemented yet!");
257 void operator=(const StringMap &RHS) {
258 assert(RHS.empty() &&
259 "assignment from non-empty stringmap not implemented yet!");
264 typedef typename ReferenceAdder<AllocatorTy>::result AllocatorRefTy;
265 typedef typename ReferenceAdder<const AllocatorTy>::result AllocatorCRefTy;
266 AllocatorRefTy getAllocator() { return Allocator; }
267 AllocatorCRefTy getAllocator() const { return Allocator; }
269 typedef const char* key_type;
270 typedef ValueTy mapped_type;
271 typedef StringMapEntry<ValueTy> value_type;
272 typedef size_t size_type;
274 typedef StringMapConstIterator<ValueTy> const_iterator;
275 typedef StringMapIterator<ValueTy> iterator;
278 return iterator(TheTable, NumBuckets == 0);
281 return iterator(TheTable+NumBuckets, true);
283 const_iterator begin() const {
284 return const_iterator(TheTable, NumBuckets == 0);
286 const_iterator end() const {
287 return const_iterator(TheTable+NumBuckets, true);
290 iterator find(StringRef Key) {
291 int Bucket = FindKey(Key);
292 if (Bucket == -1) return end();
293 return iterator(TheTable+Bucket, true);
296 const_iterator find(StringRef Key) const {
297 int Bucket = FindKey(Key);
298 if (Bucket == -1) return end();
299 return const_iterator(TheTable+Bucket, true);
302 /// lookup - Return the entry for the specified key, or a default
303 /// constructed value if no such entry exists.
304 ValueTy lookup(StringRef Key) const {
305 const_iterator it = find(Key);
311 ValueTy &operator[](StringRef Key) {
312 return GetOrCreateValue(Key).getValue();
315 size_type count(StringRef Key) const {
316 return find(Key) == end() ? 0 : 1;
319 /// insert - Insert the specified key/value pair into the map. If the key
320 /// already exists in the map, return false and ignore the request, otherwise
321 /// insert it and return true.
322 bool insert(MapEntryTy *KeyValue) {
323 unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
324 StringMapEntryBase *&Bucket = TheTable[BucketNo];
325 if (Bucket && Bucket != getTombstoneVal())
326 return false; // Already exists in map.
328 if (Bucket == getTombstoneVal())
332 assert(NumItems + NumTombstones <= NumBuckets);
338 // clear - Empties out the StringMap
342 // Zap all values, resetting the keys back to non-present (not tombstone),
343 // which is safe because we're removing all elements.
344 for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
345 StringMapEntryBase *&Bucket = TheTable[I];
346 if (Bucket && Bucket != getTombstoneVal()) {
347 static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
356 /// GetOrCreateValue - Look up the specified key in the table. If a value
357 /// exists, return it. Otherwise, default construct a value, insert it, and
359 template <typename InitTy>
360 MapEntryTy &GetOrCreateValue(StringRef Key, InitTy Val) {
361 unsigned BucketNo = LookupBucketFor(Key);
362 StringMapEntryBase *&Bucket = TheTable[BucketNo];
363 if (Bucket && Bucket != getTombstoneVal())
364 return *static_cast<MapEntryTy*>(Bucket);
366 MapEntryTy *NewItem =
367 MapEntryTy::Create(Key.begin(), Key.end(), Allocator, Val);
369 if (Bucket == getTombstoneVal())
372 assert(NumItems + NumTombstones <= NumBuckets);
374 // Fill in the bucket for the hash table. The FullHashValue was already
375 // filled in by LookupBucketFor.
382 MapEntryTy &GetOrCreateValue(StringRef Key) {
383 return GetOrCreateValue(Key, ValueTy());
386 /// remove - Remove the specified key/value pair from the map, but do not
387 /// erase it. This aborts if the key is not in the map.
388 void remove(MapEntryTy *KeyValue) {
392 void erase(iterator I) {
395 V.Destroy(Allocator);
398 bool erase(StringRef Key) {
399 iterator I = find(Key);
400 if (I == end()) return false;
412 template<typename ValueTy>
413 class StringMapConstIterator {
415 StringMapEntryBase **Ptr;
417 typedef StringMapEntry<ValueTy> value_type;
419 StringMapConstIterator() : Ptr(0) { }
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 == 0 || *Ptr == StringMapImpl::getTombstoneVal())
457 template<typename ValueTy>
458 class StringMapIterator : public StringMapConstIterator<ValueTy> {
460 StringMapIterator() : StringMapConstIterator<ValueTy>() {}
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);