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; }
107 /// StringMapEntry - This is used to represent one value that is inserted into
108 /// a StringMap. It contains the Value itself and the key: the string length
110 template<typename ValueTy>
111 class StringMapEntry : public StringMapEntryBase {
115 explicit StringMapEntry(unsigned strLen)
116 : StringMapEntryBase(strLen), second() {}
117 StringMapEntry(unsigned strLen, const ValueTy &V)
118 : StringMapEntryBase(strLen), second(V) {}
120 StringRef getKey() const {
121 return StringRef(getKeyData(), getKeyLength());
124 const ValueTy &getValue() const { return second; }
125 ValueTy &getValue() { return second; }
127 void setValue(const ValueTy &V) { second = V; }
129 /// getKeyData - Return the start of the string data that is the key for this
130 /// value. The string data is always stored immediately after the
131 /// StringMapEntry object.
132 const char *getKeyData() const {return reinterpret_cast<const char*>(this+1);}
134 StringRef first() const { return StringRef(getKeyData(), getKeyLength()); }
136 /// Create - Create a StringMapEntry for the specified key and default
137 /// construct the value.
138 template<typename AllocatorTy, typename InitType>
139 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
140 AllocatorTy &Allocator,
142 unsigned KeyLength = static_cast<unsigned>(KeyEnd-KeyStart);
144 // Okay, the item doesn't already exist, and 'Bucket' is the bucket to fill
145 // in. Allocate a new item with space for the string at the end and a null
148 unsigned AllocSize = static_cast<unsigned>(sizeof(StringMapEntry))+
150 unsigned Alignment = alignOf<StringMapEntry>();
152 StringMapEntry *NewItem =
153 static_cast<StringMapEntry*>(Allocator.Allocate(AllocSize,Alignment));
155 // Default construct the value.
156 new (NewItem) StringMapEntry(KeyLength);
158 // Copy the string information.
159 char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
160 memcpy(StrBuffer, KeyStart, KeyLength);
161 StrBuffer[KeyLength] = 0; // Null terminate for convenience of clients.
163 // Initialize the value if the client wants to.
164 StringMapEntryInitializer<ValueTy>::Initialize(*NewItem, InitVal);
168 template<typename AllocatorTy>
169 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
170 AllocatorTy &Allocator) {
171 return Create(KeyStart, KeyEnd, Allocator, 0);
174 /// Create - Create a StringMapEntry with normal malloc/free.
175 template<typename InitType>
176 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd,
179 return Create(KeyStart, KeyEnd, A, InitVal);
182 static StringMapEntry *Create(const char *KeyStart, const char *KeyEnd) {
183 return Create(KeyStart, KeyEnd, ValueTy());
186 /// GetStringMapEntryFromValue - Given a value that is known to be embedded
187 /// into a StringMapEntry, return the StringMapEntry itself.
188 static StringMapEntry &GetStringMapEntryFromValue(ValueTy &V) {
189 StringMapEntry *EPtr = 0;
190 char *Ptr = reinterpret_cast<char*>(&V) -
191 (reinterpret_cast<char*>(&EPtr->second) -
192 reinterpret_cast<char*>(EPtr));
193 return *reinterpret_cast<StringMapEntry*>(Ptr);
195 static const StringMapEntry &GetStringMapEntryFromValue(const ValueTy &V) {
196 return GetStringMapEntryFromValue(const_cast<ValueTy&>(V));
199 /// GetStringMapEntryFromKeyData - Given key data that is known to be embedded
200 /// into a StringMapEntry, return the StringMapEntry itself.
201 static StringMapEntry &GetStringMapEntryFromKeyData(const char *KeyData) {
202 char *Ptr = const_cast<char*>(KeyData) - sizeof(StringMapEntry<ValueTy>);
203 return *reinterpret_cast<StringMapEntry*>(Ptr);
206 /// Destroy - Destroy this StringMapEntry, releasing memory back to the
207 /// specified allocator.
208 template<typename AllocatorTy>
209 void Destroy(AllocatorTy &Allocator) {
210 // Free memory referenced by the item.
211 this->~StringMapEntry();
212 Allocator.Deallocate(this);
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(const StringMap &RHS)
245 : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
246 assert(RHS.empty() &&
247 "Copy ctor from non-empty stringmap not implemented yet!");
250 void operator=(const StringMap &RHS) {
251 assert(RHS.empty() &&
252 "assignment from non-empty stringmap not implemented yet!");
257 typedef typename ReferenceAdder<AllocatorTy>::result AllocatorRefTy;
258 typedef typename ReferenceAdder<const AllocatorTy>::result AllocatorCRefTy;
259 AllocatorRefTy getAllocator() { return Allocator; }
260 AllocatorCRefTy getAllocator() const { return Allocator; }
262 typedef const char* key_type;
263 typedef ValueTy mapped_type;
264 typedef StringMapEntry<ValueTy> value_type;
265 typedef size_t size_type;
267 typedef StringMapConstIterator<ValueTy> const_iterator;
268 typedef StringMapIterator<ValueTy> iterator;
271 return iterator(TheTable, NumBuckets == 0);
274 return iterator(TheTable+NumBuckets, true);
276 const_iterator begin() const {
277 return const_iterator(TheTable, NumBuckets == 0);
279 const_iterator end() const {
280 return const_iterator(TheTable+NumBuckets, true);
283 iterator find(StringRef Key) {
284 int Bucket = FindKey(Key);
285 if (Bucket == -1) return end();
286 return iterator(TheTable+Bucket, true);
289 const_iterator find(StringRef Key) const {
290 int Bucket = FindKey(Key);
291 if (Bucket == -1) return end();
292 return const_iterator(TheTable+Bucket, true);
295 /// lookup - Return the entry for the specified key, or a default
296 /// constructed value if no such entry exists.
297 ValueTy lookup(StringRef Key) const {
298 const_iterator it = find(Key);
304 ValueTy &operator[](StringRef Key) {
305 return GetOrCreateValue(Key).getValue();
308 size_type count(StringRef Key) const {
309 return find(Key) == end() ? 0 : 1;
312 /// insert - Insert the specified key/value pair into the map. If the key
313 /// already exists in the map, return false and ignore the request, otherwise
314 /// insert it and return true.
315 bool insert(MapEntryTy *KeyValue) {
316 unsigned BucketNo = LookupBucketFor(KeyValue->getKey());
317 StringMapEntryBase *&Bucket = TheTable[BucketNo];
318 if (Bucket && Bucket != getTombstoneVal())
319 return false; // Already exists in map.
321 if (Bucket == getTombstoneVal())
325 assert(NumItems + NumTombstones <= NumBuckets);
331 // clear - Empties out the StringMap
335 // Zap all values, resetting the keys back to non-present (not tombstone),
336 // which is safe because we're removing all elements.
337 for (unsigned I = 0, E = NumBuckets; I != E; ++I) {
338 StringMapEntryBase *&Bucket = TheTable[I];
339 if (Bucket && Bucket != getTombstoneVal()) {
340 static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
349 /// GetOrCreateValue - Look up the specified key in the table. If a value
350 /// exists, return it. Otherwise, default construct a value, insert it, and
352 template <typename InitTy>
353 MapEntryTy &GetOrCreateValue(StringRef Key, InitTy Val) {
354 unsigned BucketNo = LookupBucketFor(Key);
355 StringMapEntryBase *&Bucket = TheTable[BucketNo];
356 if (Bucket && Bucket != getTombstoneVal())
357 return *static_cast<MapEntryTy*>(Bucket);
359 MapEntryTy *NewItem =
360 MapEntryTy::Create(Key.begin(), Key.end(), Allocator, Val);
362 if (Bucket == getTombstoneVal())
365 assert(NumItems + NumTombstones <= NumBuckets);
367 // Fill in the bucket for the hash table. The FullHashValue was already
368 // filled in by LookupBucketFor.
375 MapEntryTy &GetOrCreateValue(StringRef Key) {
376 return GetOrCreateValue(Key, ValueTy());
379 /// remove - Remove the specified key/value pair from the map, but do not
380 /// erase it. This aborts if the key is not in the map.
381 void remove(MapEntryTy *KeyValue) {
385 void erase(iterator I) {
388 V.Destroy(Allocator);
391 bool erase(StringRef Key) {
392 iterator I = find(Key);
393 if (I == end()) return false;
405 template<typename ValueTy>
406 class StringMapConstIterator {
408 StringMapEntryBase **Ptr;
410 typedef StringMapEntry<ValueTy> value_type;
412 explicit StringMapConstIterator(StringMapEntryBase **Bucket,
413 bool NoAdvance = false)
415 if (!NoAdvance) AdvancePastEmptyBuckets();
418 const value_type &operator*() const {
419 return *static_cast<StringMapEntry<ValueTy>*>(*Ptr);
421 const value_type *operator->() const {
422 return static_cast<StringMapEntry<ValueTy>*>(*Ptr);
425 bool operator==(const StringMapConstIterator &RHS) const {
426 return Ptr == RHS.Ptr;
428 bool operator!=(const StringMapConstIterator &RHS) const {
429 return Ptr != RHS.Ptr;
432 inline StringMapConstIterator& operator++() { // Preincrement
434 AdvancePastEmptyBuckets();
437 StringMapConstIterator operator++(int) { // Postincrement
438 StringMapConstIterator tmp = *this; ++*this; return tmp;
442 void AdvancePastEmptyBuckets() {
443 while (*Ptr == 0 || *Ptr == StringMapImpl::getTombstoneVal())
448 template<typename ValueTy>
449 class StringMapIterator : public StringMapConstIterator<ValueTy> {
451 explicit StringMapIterator(StringMapEntryBase **Bucket,
452 bool NoAdvance = false)
453 : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
455 StringMapEntry<ValueTy> &operator*() const {
456 return *static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);
458 StringMapEntry<ValueTy> *operator->() const {
459 return static_cast<StringMapEntry<ValueTy>*>(*this->Ptr);