lib/Transforms/ObjCARC/BlotMapVector.h

   1 //===- BlotMapVector.h - A MapVector with the blot operation -*- C++ -*----===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/ADT/DenseMap.h"
  11 #include <algorithm>
  12 #include <vector>
  13
  14 namespace llvm {
  15 /// \brief An associative container with fast insertion-order (deterministic)
  16 /// iteration over its elements. Plus the special blot operation.
  17 template <class KeyT, class ValueT> class BlotMapVector {
  18   /// Map keys to indices in Vector.
  19   typedef DenseMap<KeyT, size_t> MapTy;
  20   MapTy Map;
  21
  22   typedef std::vector<std::pair<KeyT, ValueT>> VectorTy;
  23   /// Keys and values.
  24   VectorTy Vector;
  25
  26 public:
  27   typedef typename VectorTy::iterator iterator;
  28   typedef typename VectorTy::const_iterator const_iterator;
  29   iterator begin() { return Vector.begin(); }
  30   iterator end() { return Vector.end(); }
  31   const_iterator begin() const { return Vector.begin(); }
  32   const_iterator end() const { return Vector.end(); }
  33
  34 #ifdef EXPENSIVE_CHECKS
  35   ~BlotMapVector() {
  36     assert(Vector.size() >= Map.size()); // May differ due to blotting.
  37     for (typename MapTy::const_iterator I = Map.begin(), E = Map.end(); I != E;
  38          ++I) {
  39       assert(I->second < Vector.size());
  40       assert(Vector[I->second].first == I->first);
  41     }
  42     for (typename VectorTy::const_iterator I = Vector.begin(), E = Vector.end();
  43          I != E; ++I)
  44       assert(!I->first || (Map.count(I->first) &&
  45                            Map[I->first] == size_t(I - Vector.begin())));
  46   }
  47 #endif
  48
  49   ValueT &operator[](const KeyT &Arg) {
  50     std::pair<typename MapTy::iterator, bool> Pair =
  51         Map.insert(std::make_pair(Arg, size_t(0)));
  52     if (Pair.second) {
  53       size_t Num = Vector.size();
  54       Pair.first->second = Num;
  55       Vector.push_back(std::make_pair(Arg, ValueT()));
  56       return Vector[Num].second;
  57     }
  58     return Vector[Pair.first->second].second;
  59   }
  60
  61   std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &InsertPair) {
  62     std::pair<typename MapTy::iterator, bool> Pair =
  63         Map.insert(std::make_pair(InsertPair.first, size_t(0)));
  64     if (Pair.second) {
  65       size_t Num = Vector.size();
  66       Pair.first->second = Num;
  67       Vector.push_back(InsertPair);
  68       return std::make_pair(Vector.begin() + Num, true);
  69     }
  70     return std::make_pair(Vector.begin() + Pair.first->second, false);
  71   }
  72
  73   iterator find(const KeyT &Key) {
  74     typename MapTy::iterator It = Map.find(Key);
  75     if (It == Map.end())
  76       return Vector.end();
  77     return Vector.begin() + It->second;
  78   }
  79
  80   const_iterator find(const KeyT &Key) const {
  81     typename MapTy::const_iterator It = Map.find(Key);
  82     if (It == Map.end())
  83       return Vector.end();
  84     return Vector.begin() + It->second;
  85   }
  86
  87   /// This is similar to erase, but instead of removing the element from the
  88   /// vector, it just zeros out the key in the vector. This leaves iterators
  89   /// intact, but clients must be prepared for zeroed-out keys when iterating.
  90   void blot(const KeyT &Key) {
  91     typename MapTy::iterator It = Map.find(Key);
  92     if (It == Map.end())
  93       return;
  94     Vector[It->second].first = KeyT();
  95     Map.erase(It);
  96   }
  97
  98   void clear() {
  99     Map.clear();
 100     Vector.clear();
 101   }
 102
 103   bool empty() const {
 104     assert(Map.empty() == Vector.empty());
 105     return Map.empty();
 106   }
 107 };
 108 } //