#include <cstring>
namespace llvm {
+ template<typename ValueT>
+ class StringMapConstIterator;
+ template<typename ValueT>
+ class StringMapIterator;
+
/// StringMapEntryBase - Shared base class of StringMapEntry instances.
class StringMapEntryBase {
unsigned getKeyLength() const { return StrLen; }
};
-/// StringMapVisitor - Subclasses of this class may be implemented to walk all
-/// of the items in a StringMap.
-class StringMapVisitor {
-public:
- virtual ~StringMapVisitor();
- virtual void Visit(const char *Key, StringMapEntryBase *Value) const = 0;
-};
-
/// StringMapImpl - This is the base class of StringMap that is shared among
/// all of its instantiations.
class StringMapImpl {
-protected:
+public:
/// ItemBucket - The hash table consists of an array of these. If Item is
/// non-null, this is an extant entry, otherwise, it is a hole.
struct ItemBucket {
StringMapEntryBase *Item;
};
+protected:
ItemBucket *TheTable;
unsigned NumBuckets;
unsigned NumItems;
+ unsigned NumTombstones;
unsigned ItemSize;
protected:
+ StringMapImpl(unsigned itemSize) : ItemSize(itemSize) { init(16); }
StringMapImpl(unsigned InitSize, unsigned ItemSize);
void RehashTable();
+ /// ShouldRehash - Return true if the table should be rehashed after a new
+ /// element was recently inserted.
+ bool ShouldRehash() const {
+ // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
+ // the buckets are empty (meaning that many are filled with tombstones),
+ // grow the table.
+ return NumItems*4 > NumBuckets*3 ||
+ NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
+ }
+
/// LookupBucketFor - Look up the bucket that the specified string should end
/// up in. If it already exists as a key in the map, the Item pointer for the
/// specified bucket will be non-null. Otherwise, it will be null. In either
/// of the string.
unsigned LookupBucketFor(const char *KeyStart, const char *KeyEnd);
+ /// FindKey - Look up the bucket that contains the specified key. If it exists
+ /// in the map, return the bucket number of the key. Otherwise return -1.
+ /// This does not modify the map.
+ int FindKey(const char *KeyStart, const char *KeyEnd) const;
+
+ /// RemoveKey - Remove the specified StringMapEntry from the table, but do not
+ /// delete it. This aborts if the value isn't in the table.
+ void RemoveKey(StringMapEntryBase *V);
+
+ /// RemoveKey - Remove the StringMapEntry for the specified key from the
+ /// table, returning it. If the key is not in the table, this returns null.
+ StringMapEntryBase *RemoveKey(const char *KeyStart, const char *KeyEnd);
+private:
+ void init(unsigned Size);
public:
+ static StringMapEntryBase *getTombstoneVal() {
+ return (StringMapEntryBase*)-1;
+ }
+
unsigned getNumBuckets() const { return NumBuckets; }
unsigned getNumItems() const { return NumItems; }
- void VisitEntries(const StringMapVisitor &Visitor) const;
+ bool empty() const { return NumItems == 0; }
+ unsigned size() const { return NumItems; }
};
/// StringMapEntry - This is used to represent one value that is inserted into
AllocatorTy Allocator;
typedef StringMapEntry<ValueTy> MapEntryTy;
public:
- StringMap(unsigned InitialSize = 0)
+ StringMap() : StringMapImpl(sizeof(MapEntryTy)) {}
+ StringMap(unsigned InitialSize)
: StringMapImpl(InitialSize, sizeof(MapEntryTy)) {}
AllocatorTy &getAllocator() { return Allocator; }
const AllocatorTy &getAllocator() const { return Allocator; }
- /// FindValue - Look up the specified key in the map. If it exists, return a
- /// pointer to the element, otherwise return null.
- MapEntryTy *FindValue(const char *KeyStart, const char *KeyEnd) {
- unsigned BucketNo = LookupBucketFor(KeyStart, KeyEnd);
- return static_cast<MapEntryTy*>(TheTable[BucketNo].Item);
+ typedef StringMapConstIterator<ValueTy> const_iterator;
+ typedef StringMapIterator<ValueTy> iterator;
+
+ iterator begin() {
+ return iterator(TheTable, NumBuckets == 0);
+ }
+ iterator end() {
+ return iterator(TheTable+NumBuckets, true);
+ }
+ const_iterator begin() const {
+ return const_iterator(TheTable, NumBuckets == 0);
+ }
+ const_iterator end() const {
+ return const_iterator(TheTable+NumBuckets, true);
+ }
+
+ iterator find(const char *KeyStart, const char *KeyEnd) {
+ int Bucket = FindKey(KeyStart, KeyEnd);
+ if (Bucket == -1) return end();
+ return iterator(TheTable+Bucket);
+ }
+
+ const_iterator find(const char *KeyStart, const char *KeyEnd) const {
+ int Bucket = FindKey(KeyStart, KeyEnd);
+ if (Bucket == -1) return end();
+ return const_iterator(TheTable+Bucket);
+ }
+
+ /// insert - Insert the specified key/value pair into the map. If the key
+ /// already exists in the map, return false and ignore the request, otherwise
+ /// insert it and return true.
+ bool insert(MapEntryTy *KeyValue) {
+ unsigned BucketNo =
+ LookupBucketFor(KeyValue->getKeyData(),
+ KeyValue->getKeyData()+KeyValue->getKeyLength());
+ ItemBucket &Bucket = TheTable[BucketNo];
+ if (Bucket.Item && Bucket.Item != getTombstoneVal())
+ return false; // Already exists in map.
+
+ if (Bucket.Item == getTombstoneVal())
+ --NumTombstones;
+ Bucket.Item = KeyValue;
+ ++NumItems;
+
+ if (ShouldRehash())
+ RehashTable();
+ return true;
}
/// GetOrCreateValue - Look up the specified key in the table. If a value
const char *KeyEnd) {
unsigned BucketNo = LookupBucketFor(KeyStart, KeyEnd);
ItemBucket &Bucket = TheTable[BucketNo];
- if (Bucket.Item)
+ if (Bucket.Item && Bucket.Item != getTombstoneVal())
return *static_cast<MapEntryTy*>(Bucket.Item);
MapEntryTy *NewItem = MapEntryTy::Create(KeyStart, KeyEnd, Allocator);
+
+ if (Bucket.Item == getTombstoneVal())
+ --NumTombstones;
++NumItems;
// Fill in the bucket for the hash table. The FullHashValue was already
// filled in by LookupBucketFor.
Bucket.Item = NewItem;
- // If the hash table is now more than 3/4 full, rehash into a larger table.
- if (NumItems > NumBuckets*3/4)
+ if (ShouldRehash())
RehashTable();
return *NewItem;
}
+ /// remove - Remove the specified key/value pair from the map, but do not
+ /// erase it. This aborts if the key is not in the map.
+ void remove(MapEntryTy *KeyValue) {
+ RemoveKey(KeyValue);
+ }
+
~StringMap() {
for (ItemBucket *I = TheTable, *E = TheTable+NumBuckets; I != E; ++I) {
- if (MapEntryTy *Id = static_cast<MapEntryTy*>(I->Item))
- Id->Destroy(Allocator);
+ if (I->Item && I->Item != getTombstoneVal())
+ static_cast<MapEntryTy*>(I->Item)->Destroy(Allocator);
}
- delete [] TheTable;
+ free(TheTable);
}
};
+
+template<typename ValueTy>
+class StringMapConstIterator {
+protected:
+ StringMapImpl::ItemBucket *Ptr;
+public:
+ StringMapConstIterator(StringMapImpl::ItemBucket *Bucket,
+ bool NoAdvance = false)
+ : Ptr(Bucket) {
+ if (!NoAdvance) AdvancePastEmptyBuckets();
+ }
+
+ const StringMapEntry<ValueTy> &operator*() const {
+ return *static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
+ }
+ const StringMapEntry<ValueTy> *operator->() const {
+ return static_cast<StringMapEntry<ValueTy>*>(Ptr->Item);
+ }
+
+ bool operator==(const StringMapConstIterator &RHS) const {
+ return Ptr == RHS.Ptr;
+ }
+ bool operator!=(const StringMapConstIterator &RHS) const {
+ return Ptr != RHS.Ptr;
+ }
+
+ inline StringMapConstIterator& operator++() { // Preincrement
+ ++Ptr;
+ AdvancePastEmptyBuckets();
+ return *this;
+ }
+ StringMapConstIterator operator++(int) { // Postincrement
+ StringMapConstIterator tmp = *this; ++*this; return tmp;
+ }
+
+private:
+ void AdvancePastEmptyBuckets() {
+ while (Ptr->Item == 0 || Ptr->Item == StringMapImpl::getTombstoneVal())
+ ++Ptr;
+ }
+};
+
+template<typename ValueTy>
+class StringMapIterator : public StringMapConstIterator<ValueTy> {
+public:
+ StringMapIterator(StringMapImpl::ItemBucket *Bucket,
+ bool NoAdvance = false)
+ : StringMapConstIterator<ValueTy>(Bucket, NoAdvance) {
+ }
+ StringMapEntry<ValueTy> &operator*() const {
+ return *static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
+ }
+ StringMapEntry<ValueTy> *operator->() const {
+ return static_cast<StringMapEntry<ValueTy>*>(this->Ptr->Item);
+ }
+};
+
}
#endif
projects / oota-llvm.git / blobdiff