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 functions.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_ADT_STLEXTRAS_H
18 #define LLVM_ADT_STLEXTRAS_H
20 #include <cstddef> // for std::size_t
21 #include <cstdlib> // for qsort
24 #include <utility> // for std::pair
28 //===----------------------------------------------------------------------===//
29 // Extra additions to <functional>
30 //===----------------------------------------------------------------------===//
33 struct identity : public std::unary_function<Ty, Ty> {
34 Ty &operator()(Ty &self) const {
37 const Ty &operator()(const Ty &self) const {
43 struct less_ptr : public std::binary_function<Ty, Ty, bool> {
44 bool operator()(const Ty* left, const Ty* right) const {
45 return *left < *right;
50 struct greater_ptr : public std::binary_function<Ty, Ty, bool> {
51 bool operator()(const Ty* left, const Ty* right) const {
52 return *right < *left;
56 // deleter - Very very very simple method that is used to invoke operator
57 // delete on something. It is used like this:
59 // for_each(V.begin(), B.end(), deleter<Interval>);
62 inline void deleter(T *Ptr) {
68 //===----------------------------------------------------------------------===//
69 // Extra additions to <iterator>
70 //===----------------------------------------------------------------------===//
72 // mapped_iterator - This is a simple iterator adapter that causes a function to
73 // be dereferenced whenever operator* is invoked on the iterator.
75 template <class RootIt, class UnaryFunc>
76 class mapped_iterator {
80 typedef typename std::iterator_traits<RootIt>::iterator_category
82 typedef typename std::iterator_traits<RootIt>::difference_type
84 typedef typename UnaryFunc::result_type value_type;
87 //typedef typename UnaryFunc::result_type *pointer;
88 typedef void reference; // Can't modify value returned by fn
90 typedef RootIt iterator_type;
91 typedef mapped_iterator<RootIt, UnaryFunc> _Self;
93 inline const RootIt &getCurrent() const { return current; }
94 inline const UnaryFunc &getFunc() const { return Fn; }
96 inline explicit mapped_iterator(const RootIt &I, UnaryFunc F)
97 : current(I), Fn(F) {}
98 inline mapped_iterator(const mapped_iterator &It)
99 : current(It.current), Fn(It.Fn) {}
101 inline value_type operator*() const { // All this work to do this
102 return Fn(*current); // little change
105 _Self& operator++() { ++current; return *this; }
106 _Self& operator--() { --current; return *this; }
107 _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; }
108 _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; }
109 _Self operator+ (difference_type n) const {
110 return _Self(current + n, Fn);
112 _Self& operator+= (difference_type n) { current += n; return *this; }
113 _Self operator- (difference_type n) const {
114 return _Self(current - n, Fn);
116 _Self& operator-= (difference_type n) { current -= n; return *this; }
117 reference operator[](difference_type n) const { return *(*this + n); }
119 inline bool operator!=(const _Self &X) const { return !operator==(X); }
120 inline bool operator==(const _Self &X) const { return current == X.current; }
121 inline bool operator< (const _Self &X) const { return current < X.current; }
123 inline difference_type operator-(const _Self &X) const {
124 return current - X.current;
128 template <class _Iterator, class Func>
129 inline mapped_iterator<_Iterator, Func>
130 operator+(typename mapped_iterator<_Iterator, Func>::difference_type N,
131 const mapped_iterator<_Iterator, Func>& X) {
132 return mapped_iterator<_Iterator, Func>(X.getCurrent() - N, X.getFunc());
136 // map_iterator - Provide a convenient way to create mapped_iterators, just like
137 // make_pair is useful for creating pairs...
139 template <class ItTy, class FuncTy>
140 inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) {
141 return mapped_iterator<ItTy, FuncTy>(I, F);
144 //===----------------------------------------------------------------------===//
145 // Extra additions to <utility>
146 //===----------------------------------------------------------------------===//
148 // tie - this function ties two objects and returns a temporary object
149 // that is assignable from a std::pair. This can be used to make code
150 // more readable when using values returned from functions bundled in
151 // a std::pair. Since an example is worth 1000 words:
153 // typedef std::map<int, int> Int2IntMap;
156 // Int2IntMap::iterator where;
158 // tie(where, inserted) = myMap.insert(std::make_pair(123,456));
164 template <typename T1, typename T2>
166 typedef T1 &first_type;
167 typedef T2 &second_type;
172 tier(first_type f, second_type s) : first(f), second(s) { }
173 tier& operator=(const std::pair<T1, T2>& p) {
180 template <typename T1, typename T2>
181 inline tier<T1, T2> tie(T1& f, T2& s) {
182 return tier<T1, T2>(f, s);
185 /// \brief Function object to check whether the first component of a std::pair
186 /// compares less than the first component of another std::pair.
188 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
189 return lhs.first < rhs.first;
193 /// \brief Function object to check whether the second component of a std::pair
194 /// compares less than the second component of another std::pair.
196 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
197 return lhs.second < rhs.second;
201 //===----------------------------------------------------------------------===//
202 // Extra additions for 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 (&)[N]) {
219 /// array_pod_sort_comparator - This is helper function for array_pod_sort,
220 /// which just uses operator< on T.
222 inline int array_pod_sort_comparator(const void *P1, const void *P2) {
223 if (*reinterpret_cast<const T*>(P1) < *reinterpret_cast<const T*>(P2))
225 if (*reinterpret_cast<const T*>(P2) < *reinterpret_cast<const T*>(P1))
230 /// get_array_pod_sort_comparator - This is an internal helper function used to
231 /// get type deduction of T right.
233 inline int (*get_array_pod_sort_comparator(const T &))
234 (const void*, const void*) {
235 return array_pod_sort_comparator<T>;
239 /// array_pod_sort - This sorts an array with the specified start and end
240 /// extent. This is just like std::sort, except that it calls qsort instead of
241 /// using an inlined template. qsort is slightly slower than std::sort, but
242 /// most sorts are not performance critical in LLVM and std::sort has to be
243 /// template instantiated for each type, leading to significant measured code
244 /// bloat. This function should generally be used instead of std::sort where
247 /// This function assumes that you have simple POD-like types that can be
248 /// compared with operator< and can be moved with memcpy. If this isn't true,
249 /// you should use std::sort.
251 /// NOTE: If qsort_r were portable, we could allow a custom comparator and
252 /// default to std::less.
253 template<class IteratorTy>
254 inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
255 // Don't dereference start iterator of empty sequence.
256 if (Start == End) return;
257 qsort(&*Start, End-Start, sizeof(*Start),
258 get_array_pod_sort_comparator(*Start));
261 template <class IteratorTy>
262 inline void array_pod_sort(
263 IteratorTy Start, IteratorTy End,
265 const typename std::iterator_traits<IteratorTy>::value_type *,
266 const typename std::iterator_traits<IteratorTy>::value_type *)) {
267 // Don't dereference start iterator of empty sequence.
268 if (Start == End) return;
269 qsort(&*Start, End - Start, sizeof(*Start),
270 reinterpret_cast<int (*)(const void *, const void *)>(Compare));
273 //===----------------------------------------------------------------------===//
274 // Extra additions to <algorithm>
275 //===----------------------------------------------------------------------===//
277 /// For a container of pointers, deletes the pointers and then clears the
279 template<typename Container>
280 void DeleteContainerPointers(Container &C) {
281 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
286 /// In a container of pairs (usually a map) whose second element is a pointer,
287 /// deletes the second elements and then clears the container.
288 template<typename Container>
289 void DeleteContainerSeconds(Container &C) {
290 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
295 } // End llvm namespace