1 //===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains some templates that are useful if you are working with the
13 // No library is required when using these functinons.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_ADT_STLEXTRAS_H
18 #define LLVM_ADT_STLEXTRAS_H
21 #include <utility> // for std::pair
22 #include "llvm/ADT/iterator"
26 //===----------------------------------------------------------------------===//
27 // Extra additions to <functional>
28 //===----------------------------------------------------------------------===//
31 struct greater_ptr : public std::binary_function<Ty, Ty, bool> {
32 bool operator()(const Ty* left, const Ty* right) const {
33 return *right < *left;
37 // deleter - Very very very simple method that is used to invoke operator
38 // delete on something. It is used like this:
40 // for_each(V.begin(), B.end(), deleter<Interval>);
43 static inline void deleter(T *Ptr) {
49 //===----------------------------------------------------------------------===//
50 // Extra additions to <iterator>
51 //===----------------------------------------------------------------------===//
53 // mapped_iterator - This is a simple iterator adapter that causes a function to
54 // be dereferenced whenever operator* is invoked on the iterator.
56 template <class RootIt, class UnaryFunc>
57 class mapped_iterator {
61 typedef typename std::iterator_traits<RootIt>::iterator_category
63 typedef typename std::iterator_traits<RootIt>::difference_type
65 typedef typename UnaryFunc::result_type value_type;
68 //typedef typename UnaryFunc::result_type *pointer;
69 typedef void reference; // Can't modify value returned by fn
71 typedef RootIt iterator_type;
72 typedef mapped_iterator<RootIt, UnaryFunc> _Self;
74 inline RootIt &getCurrent() const { return current; }
76 inline explicit mapped_iterator(const RootIt &I, UnaryFunc F)
77 : current(I), Fn(F) {}
78 inline mapped_iterator(const mapped_iterator &It)
79 : current(It.current), Fn(It.Fn) {}
81 inline value_type operator*() const { // All this work to do this
82 return Fn(*current); // little change
85 _Self& operator++() { ++current; return *this; }
86 _Self& operator--() { --current; return *this; }
87 _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; }
88 _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; }
89 _Self operator+ (difference_type n) const { return _Self(current + n); }
90 _Self& operator+= (difference_type n) { current += n; return *this; }
91 _Self operator- (difference_type n) const { return _Self(current - n); }
92 _Self& operator-= (difference_type n) { current -= n; return *this; }
93 reference operator[](difference_type n) const { return *(*this + n); }
95 inline bool operator!=(const _Self &X) const { return !operator==(X); }
96 inline bool operator==(const _Self &X) const { return current == X.current; }
97 inline bool operator< (const _Self &X) const { return current < X.current; }
99 inline difference_type operator-(const _Self &X) const {
100 return current - X.current;
104 template <class _Iterator, class Func>
105 inline mapped_iterator<_Iterator, Func>
106 operator+(typename mapped_iterator<_Iterator, Func>::difference_type N,
107 const mapped_iterator<_Iterator, Func>& X) {
108 return mapped_iterator<_Iterator, Func>(X.getCurrent() - N);
112 // map_iterator - Provide a convenient way to create mapped_iterators, just like
113 // make_pair is useful for creating pairs...
115 template <class ItTy, class FuncTy>
116 inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) {
117 return mapped_iterator<ItTy, FuncTy>(I, F);
121 // next/prior - These functions unlike std::advance do not modify the
122 // passed iterator but return a copy.
124 // next(myIt) returns copy of myIt incremented once
125 // next(myIt, n) returns copy of myIt incremented n times
126 // prior(myIt) returns copy of myIt decremented once
127 // prior(myIt, n) returns copy of myIt decremented n times
129 template <typename ItTy, typename Dist>
130 inline ItTy next(ItTy it, Dist n)
136 template <typename ItTy>
137 inline ItTy next(ItTy it)
143 template <typename ItTy, typename Dist>
144 inline ItTy prior(ItTy it, Dist n)
146 std::advance(it, -n);
150 template <typename ItTy>
151 inline ItTy prior(ItTy it)
153 std::advance(it, -1);
157 //===----------------------------------------------------------------------===//
158 // Extra additions to <utility>
159 //===----------------------------------------------------------------------===//
161 // tie - this function ties two objects and returns a temporary object
162 // that is assignable from a std::pair. This can be used to make code
163 // more readable when using values returned from functions bundled in
164 // a std::pair. Since an example is worth 1000 words:
166 // typedef std::map<int, int> Int2IntMap;
169 // Int2IntMap::iterator where;
171 // tie(where, inserted) = myMap.insert(std::make_pair(123,456));
180 template <typename T1, typename T2>
182 typedef T1 &first_type;
183 typedef T2 &second_type;
188 tier(first_type f, second_type s) : first(f), second(s) { }
189 tier& operator=(const std::pair<T1, T2>& p) {
197 template <typename T1, typename T2>
198 inline tier<T1, T2> tie(T1& f, T2& s) {
199 return tier<T1, T2>(f, s);
202 } // End llvm namespace