llvm-6502/include/llvm/ADT/DenseSet.h
Benjamin Kramer 2cd5836249 Make the DenseMap bucket type configurable and use a smaller bucket for DenseSet.
DenseSet used to be implemented as DenseMap<Key, char>, which usually doubled
the memory footprint of the map. Now we use a compressed set so the second
element uses no memory at all. This required some surgery on DenseMap as
all accesses to the bucket now have to go through methods; this should
have no impact on the behavior of DenseMap though. The new default bucket
type for DenseMap is a slightly extended std::pair as we expose it through
DenseMap's iterator and don't want to break any existing users.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223588 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 19:22:44 +00:00

163 lines
4.9 KiB
C++

//===- llvm/ADT/DenseSet.h - Dense probed hash table ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the DenseSet class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_DENSESET_H
#define LLVM_ADT_DENSESET_H
#include "llvm/ADT/DenseMap.h"
namespace llvm {
namespace detail {
struct DenseSetEmpty {};
// Use the empty base class trick so we can create a DenseMap where the buckets
// contain only a single item.
template <typename KeyT> class DenseSetPair : public DenseSetEmpty {
KeyT key;
public:
KeyT &getFirst() { return key; }
const KeyT &getFirst() const { return key; }
DenseSetEmpty &getSecond() { return *this; }
const DenseSetEmpty &getSecond() const { return *this; }
};
}
/// DenseSet - This implements a dense probed hash-table based set.
template<typename ValueT, typename ValueInfoT = DenseMapInfo<ValueT> >
class DenseSet {
typedef DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
detail::DenseSetPair<ValueT>> MapTy;
static_assert(sizeof(typename MapTy::value_type) == sizeof(ValueT),
"DenseMap buckets unexpectedly large!");
MapTy TheMap;
public:
typedef ValueT key_type;
typedef ValueT value_type;
typedef unsigned size_type;
explicit DenseSet(unsigned NumInitBuckets = 0) : TheMap(NumInitBuckets) {}
bool empty() const { return TheMap.empty(); }
size_type size() const { return TheMap.size(); }
size_t getMemorySize() const { return TheMap.getMemorySize(); }
/// Grow the DenseSet so that it has at least Size buckets. Will not shrink
/// the Size of the set.
void resize(size_t Size) { TheMap.resize(Size); }
void clear() {
TheMap.clear();
}
/// Return 1 if the specified key is in the set, 0 otherwise.
size_type count(const ValueT &V) const {
return TheMap.count(V);
}
bool erase(const ValueT &V) {
return TheMap.erase(V);
}
void swap(DenseSet& RHS) {
TheMap.swap(RHS.TheMap);
}
// Iterators.
class Iterator {
typename MapTy::iterator I;
friend class DenseSet;
public:
typedef typename MapTy::iterator::difference_type difference_type;
typedef ValueT value_type;
typedef value_type *pointer;
typedef value_type &reference;
typedef std::forward_iterator_tag iterator_category;
Iterator(const typename MapTy::iterator &i) : I(i) {}
ValueT &operator*() { return I->getFirst(); }
ValueT *operator->() { return &I->getFirst(); }
Iterator& operator++() { ++I; return *this; }
bool operator==(const Iterator& X) const { return I == X.I; }
bool operator!=(const Iterator& X) const { return I != X.I; }
};
class ConstIterator {
typename MapTy::const_iterator I;
friend class DenseSet;
public:
typedef typename MapTy::const_iterator::difference_type difference_type;
typedef ValueT value_type;
typedef value_type *pointer;
typedef value_type &reference;
typedef std::forward_iterator_tag iterator_category;
ConstIterator(const typename MapTy::const_iterator &i) : I(i) {}
const ValueT &operator*() { return I->getFirst(); }
const ValueT *operator->() { return &I->getFirst(); }
ConstIterator& operator++() { ++I; return *this; }
bool operator==(const ConstIterator& X) const { return I == X.I; }
bool operator!=(const ConstIterator& X) const { return I != X.I; }
};
typedef Iterator iterator;
typedef ConstIterator const_iterator;
iterator begin() { return Iterator(TheMap.begin()); }
iterator end() { return Iterator(TheMap.end()); }
const_iterator begin() const { return ConstIterator(TheMap.begin()); }
const_iterator end() const { return ConstIterator(TheMap.end()); }
iterator find(const ValueT &V) { return Iterator(TheMap.find(V)); }
/// Alternative version of find() which allows a different, and possibly less
/// expensive, key type.
/// The DenseMapInfo is responsible for supplying methods
/// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key type
/// used.
template <class LookupKeyT>
iterator find_as(const LookupKeyT &Val) {
return Iterator(TheMap.find_as(Val));
}
template <class LookupKeyT>
const_iterator find_as(const LookupKeyT &Val) const {
return ConstIterator(TheMap.find_as(Val));
}
void erase(Iterator I) { return TheMap.erase(I.I); }
void erase(ConstIterator CI) { return TheMap.erase(CI.I); }
std::pair<iterator, bool> insert(const ValueT &V) {
detail::DenseSetEmpty Empty;
return TheMap.insert(std::make_pair(V, Empty));
}
// Range insertion of values.
template<typename InputIt>
void insert(InputIt I, InputIt E) {
for (; I != E; ++I)
insert(*I);
}
};
} // end namespace llvm
#endif