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);
145 // next/prior - These functions unlike std::advance do not modify the
146 // passed iterator but return a copy.
148 // next(myIt) returns copy of myIt incremented once
149 // next(myIt, n) returns copy of myIt incremented n times
150 // prior(myIt) returns copy of myIt decremented once
151 // prior(myIt, n) returns copy of myIt decremented n times
153 template <typename ItTy, typename Dist>
154 inline ItTy next(ItTy it, Dist n)
160 template <typename ItTy>
161 inline ItTy next(ItTy it)
166 template <typename ItTy, typename Dist>
167 inline ItTy prior(ItTy it, Dist n)
169 std::advance(it, -n);
173 template <typename ItTy>
174 inline ItTy prior(ItTy it)
179 //===----------------------------------------------------------------------===//
180 // Extra additions to <utility>
181 //===----------------------------------------------------------------------===//
183 // tie - this function ties two objects and returns a temporary object
184 // that is assignable from a std::pair. This can be used to make code
185 // more readable when using values returned from functions bundled in
186 // a std::pair. Since an example is worth 1000 words:
188 // typedef std::map<int, int> Int2IntMap;
191 // Int2IntMap::iterator where;
193 // tie(where, inserted) = myMap.insert(std::make_pair(123,456));
199 template <typename T1, typename T2>
201 typedef T1 &first_type;
202 typedef T2 &second_type;
207 tier(first_type f, second_type s) : first(f), second(s) { }
208 tier& operator=(const std::pair<T1, T2>& p) {
215 template <typename T1, typename T2>
216 inline tier<T1, T2> tie(T1& f, T2& s) {
217 return tier<T1, T2>(f, s);
220 //===----------------------------------------------------------------------===//
221 // Extra additions for arrays
222 //===----------------------------------------------------------------------===//
224 /// Find where an array ends (for ending iterators)
225 /// This returns a pointer to the byte immediately
226 /// after the end of an array.
227 template<class T, std::size_t N>
228 inline T *array_endof(T (&x)[N]) {
232 /// Find the length of an array.
233 template<class T, std::size_t N>
234 inline size_t array_lengthof(T (&)[N]) {
238 /// array_pod_sort_comparator - This is helper function for array_pod_sort,
239 /// which just uses operator< on T.
241 inline int array_pod_sort_comparator(const void *P1, const void *P2) {
242 if (*reinterpret_cast<const T*>(P1) < *reinterpret_cast<const T*>(P2))
244 if (*reinterpret_cast<const T*>(P2) < *reinterpret_cast<const T*>(P1))
249 /// get_array_pad_sort_comparator - This is an internal helper function used to
250 /// get type deduction of T right.
252 inline int (*get_array_pad_sort_comparator(const T &))
253 (const void*, const void*) {
254 return array_pod_sort_comparator<T>;
258 /// array_pod_sort - This sorts an array with the specified start and end
259 /// extent. This is just like std::sort, except that it calls qsort instead of
260 /// using an inlined template. qsort is slightly slower than std::sort, but
261 /// most sorts are not performance critical in LLVM and std::sort has to be
262 /// template instantiated for each type, leading to significant measured code
263 /// bloat. This function should generally be used instead of std::sort where
266 /// This function assumes that you have simple POD-like types that can be
267 /// compared with operator< and can be moved with memcpy. If this isn't true,
268 /// you should use std::sort.
270 /// NOTE: If qsort_r were portable, we could allow a custom comparator and
271 /// default to std::less.
272 template<class IteratorTy>
273 inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
274 // Don't dereference start iterator of empty sequence.
275 if (Start == End) return;
276 qsort(&*Start, End-Start, sizeof(*Start),
277 get_array_pad_sort_comparator(*Start));
280 template<class IteratorTy>
281 inline void array_pod_sort(IteratorTy Start, IteratorTy End,
282 int (*Compare)(const void*, const void*)) {
283 // Don't dereference start iterator of empty sequence.
284 if (Start == End) return;
285 qsort(&*Start, End-Start, sizeof(*Start), Compare);
288 //===----------------------------------------------------------------------===//
289 // Extra additions to <algorithm>
290 //===----------------------------------------------------------------------===//
292 /// For a container of pointers, deletes the pointers and then clears the
294 template<typename Container>
295 void DeleteContainerPointers(Container &C) {
296 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
301 /// In a container of pairs (usually a map) whose second element is a pointer,
302 /// deletes the second elements and then clears the container.
303 template<typename Container>
304 void DeleteContainerSeconds(Container &C) {
305 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
310 } // End llvm namespace