LLVM API Documentation
00001 //===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 // 00010 // This file contains some templates that are useful if you are working with the 00011 // STL at all. 00012 // 00013 // No library is required when using these functinons. 00014 // 00015 //===----------------------------------------------------------------------===// 00016 00017 #ifndef LLVM_ADT_STLEXTRAS_H 00018 #define LLVM_ADT_STLEXTRAS_H 00019 00020 #include <functional> 00021 #include <utility> // for std::pair 00022 #include "llvm/ADT/iterator" 00023 00024 namespace llvm { 00025 00026 //===----------------------------------------------------------------------===// 00027 // Extra additions to <functional> 00028 //===----------------------------------------------------------------------===// 00029 00030 template<class Ty> 00031 struct greater_ptr : public std::binary_function<Ty, Ty, bool> { 00032 bool operator()(const Ty* left, const Ty* right) const { 00033 return *right < *left; 00034 } 00035 }; 00036 00037 // deleter - Very very very simple method that is used to invoke operator 00038 // delete on something. It is used like this: 00039 // 00040 // for_each(V.begin(), B.end(), deleter<Interval>); 00041 // 00042 template <class T> 00043 static inline void deleter(T *Ptr) { 00044 delete Ptr; 00045 } 00046 00047 00048 00049 //===----------------------------------------------------------------------===// 00050 // Extra additions to <iterator> 00051 //===----------------------------------------------------------------------===// 00052 00053 // mapped_iterator - This is a simple iterator adapter that causes a function to 00054 // be dereferenced whenever operator* is invoked on the iterator. 00055 // 00056 template <class RootIt, class UnaryFunc> 00057 class mapped_iterator { 00058 RootIt current; 00059 UnaryFunc Fn; 00060 public: 00061 typedef typename std::iterator_traits<RootIt>::iterator_category 00062 iterator_category; 00063 typedef typename std::iterator_traits<RootIt>::difference_type 00064 difference_type; 00065 typedef typename UnaryFunc::result_type value_type; 00066 00067 typedef void pointer; 00068 //typedef typename UnaryFunc::result_type *pointer; 00069 typedef void reference; // Can't modify value returned by fn 00070 00071 typedef RootIt iterator_type; 00072 typedef mapped_iterator<RootIt, UnaryFunc> _Self; 00073 00074 inline RootIt &getCurrent() const { return current; } 00075 00076 inline explicit mapped_iterator(const RootIt &I, UnaryFunc F) 00077 : current(I), Fn(F) {} 00078 inline mapped_iterator(const mapped_iterator &It) 00079 : current(It.current), Fn(It.Fn) {} 00080 00081 inline value_type operator*() const { // All this work to do this 00082 return Fn(*current); // little change 00083 } 00084 00085 _Self& operator++() { ++current; return *this; } 00086 _Self& operator--() { --current; return *this; } 00087 _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; } 00088 _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; } 00089 _Self operator+ (difference_type n) const { return _Self(current + n); } 00090 _Self& operator+= (difference_type n) { current += n; return *this; } 00091 _Self operator- (difference_type n) const { return _Self(current - n); } 00092 _Self& operator-= (difference_type n) { current -= n; return *this; } 00093 reference operator[](difference_type n) const { return *(*this + n); } 00094 00095 inline bool operator!=(const _Self &X) const { return !operator==(X); } 00096 inline bool operator==(const _Self &X) const { return current == X.current; } 00097 inline bool operator< (const _Self &X) const { return current < X.current; } 00098 00099 inline difference_type operator-(const _Self &X) const { 00100 return current - X.current; 00101 } 00102 }; 00103 00104 template <class _Iterator, class Func> 00105 inline mapped_iterator<_Iterator, Func> 00106 operator+(typename mapped_iterator<_Iterator, Func>::difference_type N, 00107 const mapped_iterator<_Iterator, Func>& X) { 00108 return mapped_iterator<_Iterator, Func>(X.getCurrent() - N); 00109 } 00110 00111 00112 // map_iterator - Provide a convenient way to create mapped_iterators, just like 00113 // make_pair is useful for creating pairs... 00114 // 00115 template <class ItTy, class FuncTy> 00116 inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) { 00117 return mapped_iterator<ItTy, FuncTy>(I, F); 00118 } 00119 00120 00121 // next/prior - These functions unlike std::advance do not modify the 00122 // passed iterator but return a copy. 00123 // 00124 // next(myIt) returns copy of myIt incremented once 00125 // next(myIt, n) returns copy of myIt incremented n times 00126 // prior(myIt) returns copy of myIt decremented once 00127 // prior(myIt, n) returns copy of myIt decremented n times 00128 00129 template <typename ItTy, typename Dist> 00130 inline ItTy next(ItTy it, Dist n) 00131 { 00132 std::advance(it, n); 00133 return it; 00134 } 00135 00136 template <typename ItTy> 00137 inline ItTy next(ItTy it) 00138 { 00139 std::advance(it, 1); 00140 return it; 00141 } 00142 00143 template <typename ItTy, typename Dist> 00144 inline ItTy prior(ItTy it, Dist n) 00145 { 00146 std::advance(it, -n); 00147 return it; 00148 } 00149 00150 template <typename ItTy> 00151 inline ItTy prior(ItTy it) 00152 { 00153 std::advance(it, -1); 00154 return it; 00155 } 00156 00157 //===----------------------------------------------------------------------===// 00158 // Extra additions to <utility> 00159 //===----------------------------------------------------------------------===// 00160 00161 // tie - this function ties two objects and returns a temporary object 00162 // that is assignable from a std::pair. This can be used to make code 00163 // more readable when using values returned from functions bundled in 00164 // a std::pair. Since an example is worth 1000 words: 00165 // 00166 // typedef std::map<int, int> Int2IntMap; 00167 // 00168 // Int2IntMap myMap; 00169 // Int2IntMap::iterator where; 00170 // bool inserted; 00171 // tie(where, inserted) = myMap.insert(std::make_pair(123,456)); 00172 // 00173 // if (inserted) 00174 // // do stuff 00175 // else 00176 // // do other stuff 00177 00178 namespace 00179 { 00180 template <typename T1, typename T2> 00181 struct tier { 00182 typedef T1 &first_type; 00183 typedef T2 &second_type; 00184 00185 first_type first; 00186 second_type second; 00187 00188 tier(first_type f, second_type s) : first(f), second(s) { } 00189 tier& operator=(const std::pair<T1, T2>& p) { 00190 first = p.first; 00191 second = p.second; 00192 return *this; 00193 } 00194 }; 00195 } 00196 00197 template <typename T1, typename T2> 00198 inline tier<T1, T2> tie(T1& f, T2& s) { 00199 return tier<T1, T2>(f, s); 00200 } 00201 00202 } // End llvm namespace 00203 00204 #endif