1 //===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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 <cstring> // for std::size_t
23 #include "llvm/ADT/iterator.h"
27 //===----------------------------------------------------------------------===//
28 // Extra additions to <functional>
29 //===----------------------------------------------------------------------===//
32 struct greater_ptr : public std::binary_function<Ty, Ty, bool> {
33 bool operator()(const Ty* left, const Ty* right) const {
34 return *right < *left;
38 // deleter - Very very very simple method that is used to invoke operator
39 // delete on something. It is used like this:
41 // for_each(V.begin(), B.end(), deleter<Interval>);
44 static inline void deleter(T *Ptr) {
50 //===----------------------------------------------------------------------===//
51 // Extra additions to <iterator>
52 //===----------------------------------------------------------------------===//
54 // mapped_iterator - This is a simple iterator adapter that causes a function to
55 // be dereferenced whenever operator* is invoked on the iterator.
57 template <class RootIt, class UnaryFunc>
58 class mapped_iterator {
62 typedef typename std::iterator_traits<RootIt>::iterator_category
64 typedef typename std::iterator_traits<RootIt>::difference_type
66 typedef typename UnaryFunc::result_type value_type;
69 //typedef typename UnaryFunc::result_type *pointer;
70 typedef void reference; // Can't modify value returned by fn
72 typedef RootIt iterator_type;
73 typedef mapped_iterator<RootIt, UnaryFunc> _Self;
75 inline const RootIt &getCurrent() const { return current; }
77 inline explicit mapped_iterator(const RootIt &I, UnaryFunc F)
78 : current(I), Fn(F) {}
79 inline mapped_iterator(const mapped_iterator &It)
80 : current(It.current), Fn(It.Fn) {}
82 inline value_type operator*() const { // All this work to do this
83 return Fn(*current); // little change
86 _Self& operator++() { ++current; return *this; }
87 _Self& operator--() { --current; return *this; }
88 _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; }
89 _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; }
90 _Self operator+ (difference_type n) const { return _Self(current + n); }
91 _Self& operator+= (difference_type n) { current += n; return *this; }
92 _Self operator- (difference_type n) const { return _Self(current - n); }
93 _Self& operator-= (difference_type n) { current -= n; return *this; }
94 reference operator[](difference_type n) const { return *(*this + n); }
96 inline bool operator!=(const _Self &X) const { return !operator==(X); }
97 inline bool operator==(const _Self &X) const { return current == X.current; }
98 inline bool operator< (const _Self &X) const { return current < X.current; }
100 inline difference_type operator-(const _Self &X) const {
101 return current - X.current;
105 template <class _Iterator, class Func>
106 inline mapped_iterator<_Iterator, Func>
107 operator+(typename mapped_iterator<_Iterator, Func>::difference_type N,
108 const mapped_iterator<_Iterator, Func>& X) {
109 return mapped_iterator<_Iterator, Func>(X.getCurrent() - N);
113 // map_iterator - Provide a convenient way to create mapped_iterators, just like
114 // make_pair is useful for creating pairs...
116 template <class ItTy, class FuncTy>
117 inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) {
118 return mapped_iterator<ItTy, FuncTy>(I, F);
122 // next/prior - These functions unlike std::advance do not modify the
123 // passed iterator but return a copy.
125 // next(myIt) returns copy of myIt incremented once
126 // next(myIt, n) returns copy of myIt incremented n times
127 // prior(myIt) returns copy of myIt decremented once
128 // prior(myIt, n) returns copy of myIt decremented n times
130 template <typename ItTy, typename Dist>
131 inline ItTy next(ItTy it, Dist n)
137 template <typename ItTy>
138 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)
156 //===----------------------------------------------------------------------===//
157 // Extra additions to <utility>
158 //===----------------------------------------------------------------------===//
160 // tie - this function ties two objects and returns a temporary object
161 // that is assignable from a std::pair. This can be used to make code
162 // more readable when using values returned from functions bundled in
163 // a std::pair. Since an example is worth 1000 words:
165 // typedef std::map<int, int> Int2IntMap;
168 // Int2IntMap::iterator where;
170 // tie(where, inserted) = myMap.insert(std::make_pair(123,456));
179 template <typename T1, typename T2>
181 typedef T1 &first_type;
182 typedef T2 &second_type;
187 tier(first_type f, second_type s) : first(f), second(s) { }
188 tier& operator=(const std::pair<T1, T2>& p) {
196 template <typename T1, typename T2>
197 inline tier<T1, T2> tie(T1& f, T2& s) {
198 return tier<T1, T2>(f, s);
201 //===----------------------------------------------------------------------===//
202 // Extra additions to arrays
203 //===----------------------------------------------------------------------===//
205 /// Find where an array ends (for ending iterators)
206 /// This returns a pointer to the byte immediately
207 /// after the end of an array.
208 template<class T, std::size_t N>
209 inline T *array_endof(T (&x)[N]) {
213 /// Find the length of an array.
214 template<class T, std::size_t N>
215 inline size_t array_lengthof(T (&x)[N]) {
219 } // End llvm namespace