llvm-project/llvm/lib/Transforms/ObjCARC/BlotMapVector.h

119 lines
3.6 KiB
C++

//===- BlotMapVector.h - A MapVector with the blot operation ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_BLOTMAPVECTOR_H
#define LLVM_LIB_TRANSFORMS_OBJCARC_BLOTMAPVECTOR_H
#include "llvm/ADT/DenseMap.h"
#include <cassert>
#include <cstddef>
#include <utility>
#include <vector>
namespace llvm {
/// \brief An associative container with fast insertion-order (deterministic)
/// iteration over its elements. Plus the special blot operation.
template <class KeyT, class ValueT> class BlotMapVector {
/// Map keys to indices in Vector.
using MapTy = DenseMap<KeyT, size_t>;
MapTy Map;
/// Keys and values.
using VectorTy = std::vector<std::pair<KeyT, ValueT>>;
VectorTy Vector;
public:
#ifdef EXPENSIVE_CHECKS
~BlotMapVector() {
assert(Vector.size() >= Map.size()); // May differ due to blotting.
for (typename MapTy::const_iterator I = Map.begin(), E = Map.end(); I != E;
++I) {
assert(I->second < Vector.size());
assert(Vector[I->second].first == I->first);
}
for (typename VectorTy::const_iterator I = Vector.begin(), E = Vector.end();
I != E; ++I)
assert(!I->first || (Map.count(I->first) &&
Map[I->first] == size_t(I - Vector.begin())));
}
#endif
using iterator = typename VectorTy::iterator;
using const_iterator = typename VectorTy::const_iterator;
iterator begin() { return Vector.begin(); }
iterator end() { return Vector.end(); }
const_iterator begin() const { return Vector.begin(); }
const_iterator end() const { return Vector.end(); }
ValueT &operator[](const KeyT &Arg) {
std::pair<typename MapTy::iterator, bool> Pair =
Map.insert(std::make_pair(Arg, size_t(0)));
if (Pair.second) {
size_t Num = Vector.size();
Pair.first->second = Num;
Vector.push_back(std::make_pair(Arg, ValueT()));
return Vector[Num].second;
}
return Vector[Pair.first->second].second;
}
std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &InsertPair) {
std::pair<typename MapTy::iterator, bool> Pair =
Map.insert(std::make_pair(InsertPair.first, size_t(0)));
if (Pair.second) {
size_t Num = Vector.size();
Pair.first->second = Num;
Vector.push_back(InsertPair);
return std::make_pair(Vector.begin() + Num, true);
}
return std::make_pair(Vector.begin() + Pair.first->second, false);
}
iterator find(const KeyT &Key) {
typename MapTy::iterator It = Map.find(Key);
if (It == Map.end())
return Vector.end();
return Vector.begin() + It->second;
}
const_iterator find(const KeyT &Key) const {
typename MapTy::const_iterator It = Map.find(Key);
if (It == Map.end())
return Vector.end();
return Vector.begin() + It->second;
}
/// This is similar to erase, but instead of removing the element from the
/// vector, it just zeros out the key in the vector. This leaves iterators
/// intact, but clients must be prepared for zeroed-out keys when iterating.
void blot(const KeyT &Key) {
typename MapTy::iterator It = Map.find(Key);
if (It == Map.end())
return;
Vector[It->second].first = KeyT();
Map.erase(It);
}
void clear() {
Map.clear();
Vector.clear();
}
bool empty() const {
assert(Map.empty() == Vector.empty());
return Map.empty();
}
};
} // end namespace llvm
#endif // LLVM_LIB_TRANSFORMS_OBJCARC_BLOTMAPVECTOR_H