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https://github.com/c64scene-ar/llvm-6502.git
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aef806e9cb
Added method FindAndConstruct() to DenseMap, which does the same thing as operator[], except that it refers value_type& (a reference to both the key and mapped data pair). This method is useful for clients that wish to access the stored key value, as opposed to the key used to do the actual lookup (these need not always be the same). Redefined operator[] to use FindAndConstruct() (same logic). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43594 91177308-0d34-0410-b5e6-96231b3b80d8
459 lines
15 KiB
C++
459 lines
15 KiB
C++
//===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Chris Lattner and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the DenseMap class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_DENSEMAP_H
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#define LLVM_ADT_DENSEMAP_H
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#include "llvm/Support/DataTypes.h"
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#include "llvm/Support/MathExtras.h"
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#include <cassert>
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#include <utility>
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namespace llvm {
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template<typename T>
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struct DenseMapInfo {
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//static inline T getEmptyKey();
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//static inline T getTombstoneKey();
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//static unsigned getHashValue(const T &Val);
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//static bool isEqual(const T &LHS, const T &RHS);
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//static bool isPod()
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};
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// Provide DenseMapInfo for all pointers.
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template<typename T>
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struct DenseMapInfo<T*> {
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static inline T* getEmptyKey() { return reinterpret_cast<T*>(-1); }
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static inline T* getTombstoneKey() { return reinterpret_cast<T*>(-2); }
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static unsigned getHashValue(const T *PtrVal) {
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return (unsigned((uintptr_t)PtrVal) >> 4) ^
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(unsigned((uintptr_t)PtrVal) >> 9);
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}
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static bool isEqual(const T *LHS, const T *RHS) { return LHS == RHS; }
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static bool isPod() { return true; }
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};
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template<typename KeyT, typename ValueT,
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typename KeyInfoT = DenseMapInfo<KeyT>,
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typename ValueInfoT = DenseMapInfo<ValueT> >
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class DenseMapIterator;
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template<typename KeyT, typename ValueT,
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typename KeyInfoT = DenseMapInfo<KeyT>,
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typename ValueInfoT = DenseMapInfo<ValueT> >
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class DenseMapConstIterator;
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template<typename KeyT, typename ValueT,
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typename KeyInfoT = DenseMapInfo<KeyT>,
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typename ValueInfoT = DenseMapInfo<ValueT> >
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class DenseMap {
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typedef std::pair<KeyT, ValueT> BucketT;
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unsigned NumBuckets;
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BucketT *Buckets;
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unsigned NumEntries;
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unsigned NumTombstones;
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public:
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typedef BucketT value_type;
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DenseMap(const DenseMap& other) {
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NumBuckets = 0;
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CopyFrom(other);
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}
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explicit DenseMap(unsigned NumInitBuckets = 64) {
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init(NumInitBuckets);
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}
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~DenseMap() {
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const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
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for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
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if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
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!KeyInfoT::isEqual(P->first, TombstoneKey))
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P->second.~ValueT();
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P->first.~KeyT();
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}
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delete[] reinterpret_cast<char*>(Buckets);
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}
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typedef DenseMapIterator<KeyT, ValueT, KeyInfoT> iterator;
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typedef DenseMapConstIterator<KeyT, ValueT, KeyInfoT> const_iterator;
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inline iterator begin() {
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return iterator(Buckets, Buckets+NumBuckets);
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}
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inline iterator end() {
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return iterator(Buckets+NumBuckets, Buckets+NumBuckets);
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}
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inline const_iterator begin() const {
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return const_iterator(Buckets, Buckets+NumBuckets);
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}
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inline const_iterator end() const {
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return const_iterator(Buckets+NumBuckets, Buckets+NumBuckets);
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}
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bool empty() const { return NumEntries == 0; }
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unsigned size() const { return NumEntries; }
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/// Grow the densemap so that it has at least Size buckets. Does not shrink
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void resize(size_t Size) { grow(Size); }
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void clear() {
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// If the capacity of the array is huge, and the # elements used is small,
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// shrink the array.
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if (NumEntries * 4 < NumBuckets && NumBuckets > 64) {
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shrink_and_clear();
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return;
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}
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const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
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for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
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if (!KeyInfoT::isEqual(P->first, EmptyKey)) {
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if (!KeyInfoT::isEqual(P->first, TombstoneKey)) {
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P->second.~ValueT();
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--NumEntries;
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}
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P->first = EmptyKey;
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}
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}
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assert(NumEntries == 0 && "Node count imbalance!");
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NumTombstones = 0;
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}
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/// count - Return true if the specified key is in the map.
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bool count(const KeyT &Val) const {
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BucketT *TheBucket;
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return LookupBucketFor(Val, TheBucket);
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}
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iterator find(const KeyT &Val) {
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BucketT *TheBucket;
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if (LookupBucketFor(Val, TheBucket))
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return iterator(TheBucket, Buckets+NumBuckets);
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return end();
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}
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const_iterator find(const KeyT &Val) const {
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BucketT *TheBucket;
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if (LookupBucketFor(Val, TheBucket))
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return const_iterator(TheBucket, Buckets+NumBuckets);
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return end();
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}
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bool insert(const std::pair<KeyT, ValueT> &KV) {
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BucketT *TheBucket;
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if (LookupBucketFor(KV.first, TheBucket))
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return false; // Already in map.
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// Otherwise, insert the new element.
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InsertIntoBucket(KV.first, KV.second, TheBucket);
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return true;
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}
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bool erase(const KeyT &Val) {
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BucketT *TheBucket;
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if (!LookupBucketFor(Val, TheBucket))
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return false; // not in map.
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TheBucket->second.~ValueT();
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TheBucket->first = getTombstoneKey();
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--NumEntries;
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++NumTombstones;
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return true;
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}
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bool erase(iterator I) {
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BucketT *TheBucket = &*I;
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TheBucket->second.~ValueT();
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TheBucket->first = getTombstoneKey();
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--NumEntries;
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++NumTombstones;
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return true;
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}
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value_type& FindAndConstruct(const KeyT &Key) {
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BucketT *TheBucket;
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if (LookupBucketFor(Key, TheBucket))
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return *TheBucket;
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return *InsertIntoBucket(Key, ValueT(), TheBucket);
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}
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ValueT &operator[](const KeyT &Key) {
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return FindAndConstruct(Key).second;
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}
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DenseMap& operator=(const DenseMap& other) {
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CopyFrom(other);
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return *this;
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}
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private:
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void CopyFrom(const DenseMap& other) {
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if (NumBuckets != 0 && (!KeyInfoT::isPod() || !ValueInfoT::isPod())) {
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const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
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for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
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if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
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!KeyInfoT::isEqual(P->first, TombstoneKey))
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P->second.~ValueT();
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P->first.~KeyT();
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}
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}
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NumEntries = other.NumEntries;
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NumTombstones = other.NumTombstones;
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if (NumBuckets)
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delete[] reinterpret_cast<char*>(Buckets);
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Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT) *
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other.NumBuckets]);
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if (KeyInfoT::isPod() && ValueInfoT::isPod())
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memcpy(Buckets, other.Buckets, other.NumBuckets * sizeof(BucketT));
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else
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for (size_t i = 0; i < other.NumBuckets; ++i) {
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new (Buckets[i].first) KeyT(other.Buckets[i].first);
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if (!KeyInfoT::isEqual(Buckets[i].first, getEmptyKey()) &&
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!KeyInfoT::isEqual(Buckets[i].first, getTombstoneKey()))
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new (&Buckets[i].second) ValueT(other.Buckets[i].second);
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}
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NumBuckets = other.NumBuckets;
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}
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BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
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BucketT *TheBucket) {
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// If the load of the hash table is more than 3/4, or if fewer than 1/8 of
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// the buckets are empty (meaning that many are filled with tombstones),
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// grow the table.
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//
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// The later case is tricky. For example, if we had one empty bucket with
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// tons of tombstones, failing lookups (e.g. for insertion) would have to
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// probe almost the entire table until it found the empty bucket. If the
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// table completely filled with tombstones, no lookup would ever succeed,
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// causing infinite loops in lookup.
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if (NumEntries*4 >= NumBuckets*3 ||
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NumBuckets-(NumEntries+NumTombstones) < NumBuckets/8) {
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this->grow(NumBuckets * 2);
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LookupBucketFor(Key, TheBucket);
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}
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++NumEntries;
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// If we are writing over a tombstone, remember this.
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if (!KeyInfoT::isEqual(TheBucket->first, getEmptyKey()))
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--NumTombstones;
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TheBucket->first = Key;
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new (&TheBucket->second) ValueT(Value);
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return TheBucket;
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}
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static unsigned getHashValue(const KeyT &Val) {
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return KeyInfoT::getHashValue(Val);
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}
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static const KeyT getEmptyKey() {
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return KeyInfoT::getEmptyKey();
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}
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static const KeyT getTombstoneKey() {
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return KeyInfoT::getTombstoneKey();
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}
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/// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
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/// FoundBucket. If the bucket contains the key and a value, this returns
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/// true, otherwise it returns a bucket with an empty marker or tombstone and
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/// returns false.
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bool LookupBucketFor(const KeyT &Val, BucketT *&FoundBucket) const {
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unsigned BucketNo = getHashValue(Val);
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unsigned ProbeAmt = 1;
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BucketT *BucketsPtr = Buckets;
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// FoundTombstone - Keep track of whether we find a tombstone while probing.
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BucketT *FoundTombstone = 0;
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const KeyT EmptyKey = getEmptyKey();
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const KeyT TombstoneKey = getTombstoneKey();
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assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
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!KeyInfoT::isEqual(Val, TombstoneKey) &&
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"Empty/Tombstone value shouldn't be inserted into map!");
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while (1) {
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BucketT *ThisBucket = BucketsPtr + (BucketNo & (NumBuckets-1));
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// Found Val's bucket? If so, return it.
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if (KeyInfoT::isEqual(ThisBucket->first, Val)) {
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FoundBucket = ThisBucket;
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return true;
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}
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// If we found an empty bucket, the key doesn't exist in the set.
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// Insert it and return the default value.
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if (KeyInfoT::isEqual(ThisBucket->first, EmptyKey)) {
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// If we've already seen a tombstone while probing, fill it in instead
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// of the empty bucket we eventually probed to.
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if (FoundTombstone) ThisBucket = FoundTombstone;
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FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
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return false;
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}
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// If this is a tombstone, remember it. If Val ends up not in the map, we
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// prefer to return it than something that would require more probing.
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if (KeyInfoT::isEqual(ThisBucket->first, TombstoneKey) && !FoundTombstone)
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FoundTombstone = ThisBucket; // Remember the first tombstone found.
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// Otherwise, it's a hash collision or a tombstone, continue quadratic
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// probing.
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BucketNo += ProbeAmt++;
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}
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}
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void init(unsigned InitBuckets) {
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NumEntries = 0;
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NumTombstones = 0;
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NumBuckets = InitBuckets;
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assert(InitBuckets && (InitBuckets & InitBuckets-1) == 0 &&
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"# initial buckets must be a power of two!");
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Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*InitBuckets]);
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// Initialize all the keys to EmptyKey.
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const KeyT EmptyKey = getEmptyKey();
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for (unsigned i = 0; i != InitBuckets; ++i)
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new (&Buckets[i].first) KeyT(EmptyKey);
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}
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void grow(unsigned AtLeast) {
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unsigned OldNumBuckets = NumBuckets;
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BucketT *OldBuckets = Buckets;
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// Double the number of buckets.
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while (NumBuckets <= AtLeast)
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NumBuckets <<= 1;
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NumTombstones = 0;
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Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*NumBuckets]);
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// Initialize all the keys to EmptyKey.
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const KeyT EmptyKey = getEmptyKey();
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for (unsigned i = 0, e = NumBuckets; i != e; ++i)
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new (&Buckets[i].first) KeyT(EmptyKey);
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// Insert all the old elements.
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const KeyT TombstoneKey = getTombstoneKey();
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for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
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if (!KeyInfoT::isEqual(B->first, EmptyKey) &&
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!KeyInfoT::isEqual(B->first, TombstoneKey)) {
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// Insert the key/value into the new table.
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BucketT *DestBucket;
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bool FoundVal = LookupBucketFor(B->first, DestBucket);
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FoundVal = FoundVal; // silence warning.
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assert(!FoundVal && "Key already in new map?");
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DestBucket->first = B->first;
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new (&DestBucket->second) ValueT(B->second);
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// Free the value.
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B->second.~ValueT();
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}
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B->first.~KeyT();
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}
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// Free the old table.
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delete[] reinterpret_cast<char*>(OldBuckets);
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}
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void shrink_and_clear() {
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unsigned OldNumBuckets = NumBuckets;
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BucketT *OldBuckets = Buckets;
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// Reduce the number of buckets.
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NumBuckets = NumEntries > 32 ? 1 << (Log2_32_Ceil(NumEntries) + 1)
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: 64;
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NumTombstones = 0;
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Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*NumBuckets]);
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// Initialize all the keys to EmptyKey.
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const KeyT EmptyKey = getEmptyKey();
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for (unsigned i = 0, e = NumBuckets; i != e; ++i)
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new (&Buckets[i].first) KeyT(EmptyKey);
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// Free the old buckets.
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const KeyT TombstoneKey = getTombstoneKey();
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for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
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if (!KeyInfoT::isEqual(B->first, EmptyKey) &&
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!KeyInfoT::isEqual(B->first, TombstoneKey)) {
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// Free the value.
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B->second.~ValueT();
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}
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B->first.~KeyT();
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}
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// Free the old table.
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delete[] reinterpret_cast<char*>(OldBuckets);
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NumEntries = 0;
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}
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};
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template<typename KeyT, typename ValueT, typename KeyInfoT, typename ValueInfoT>
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class DenseMapIterator {
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typedef std::pair<KeyT, ValueT> BucketT;
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protected:
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const BucketT *Ptr, *End;
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public:
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DenseMapIterator(const BucketT *Pos, const BucketT *E) : Ptr(Pos), End(E) {
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AdvancePastEmptyBuckets();
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}
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std::pair<KeyT, ValueT> &operator*() const {
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return *const_cast<BucketT*>(Ptr);
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}
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std::pair<KeyT, ValueT> *operator->() const {
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return const_cast<BucketT*>(Ptr);
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}
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bool operator==(const DenseMapIterator &RHS) const {
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return Ptr == RHS.Ptr;
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}
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bool operator!=(const DenseMapIterator &RHS) const {
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return Ptr != RHS.Ptr;
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}
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inline DenseMapIterator& operator++() { // Preincrement
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++Ptr;
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AdvancePastEmptyBuckets();
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return *this;
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}
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DenseMapIterator operator++(int) { // Postincrement
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DenseMapIterator tmp = *this; ++*this; return tmp;
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}
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private:
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void AdvancePastEmptyBuckets() {
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const KeyT Empty = KeyInfoT::getEmptyKey();
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const KeyT Tombstone = KeyInfoT::getTombstoneKey();
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while (Ptr != End &&
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(KeyInfoT::isEqual(Ptr->first, Empty) ||
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KeyInfoT::isEqual(Ptr->first, Tombstone)))
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++Ptr;
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}
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};
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template<typename KeyT, typename ValueT, typename KeyInfoT, typename ValueInfoT>
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class DenseMapConstIterator : public DenseMapIterator<KeyT, ValueT, KeyInfoT> {
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public:
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DenseMapConstIterator(const std::pair<KeyT, ValueT> *Pos,
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const std::pair<KeyT, ValueT> *E)
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: DenseMapIterator<KeyT, ValueT, KeyInfoT>(Pos, E) {
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}
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const std::pair<KeyT, ValueT> &operator*() const {
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return *this->Ptr;
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}
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const std::pair<KeyT, ValueT> *operator->() const {
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return this->Ptr;
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}
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};
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} // end namespace llvm
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#endif
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