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 less_ptr : public std::binary_function<Ty, Ty, bool> {
34 bool operator()(const Ty* left, const Ty* right) const {
35 return *left < *right;
40 struct greater_ptr : public std::binary_function<Ty, Ty, bool> {
41 bool operator()(const Ty* left, const Ty* right) const {
42 return *right < *left;
46 // deleter - Very very very simple method that is used to invoke operator
47 // delete on something. It is used like this:
49 // for_each(V.begin(), B.end(), deleter<Interval>);
52 static inline void deleter(T *Ptr) {
58 //===----------------------------------------------------------------------===//
59 // Extra additions to <iterator>
60 //===----------------------------------------------------------------------===//
62 // mapped_iterator - This is a simple iterator adapter that causes a function to
63 // be dereferenced whenever operator* is invoked on the iterator.
65 template <class RootIt, class UnaryFunc>
66 class mapped_iterator {
70 typedef typename std::iterator_traits<RootIt>::iterator_category
72 typedef typename std::iterator_traits<RootIt>::difference_type
74 typedef typename UnaryFunc::result_type value_type;
77 //typedef typename UnaryFunc::result_type *pointer;
78 typedef void reference; // Can't modify value returned by fn
80 typedef RootIt iterator_type;
81 typedef mapped_iterator<RootIt, UnaryFunc> _Self;
83 inline const RootIt &getCurrent() const { return current; }
84 inline const UnaryFunc &getFunc() const { return Fn; }
86 inline explicit mapped_iterator(const RootIt &I, UnaryFunc F)
87 : current(I), Fn(F) {}
88 inline mapped_iterator(const mapped_iterator &It)
89 : current(It.current), Fn(It.Fn) {}
91 inline value_type operator*() const { // All this work to do this
92 return Fn(*current); // little change
95 _Self& operator++() { ++current; return *this; }
96 _Self& operator--() { --current; return *this; }
97 _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; }
98 _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; }
99 _Self operator+ (difference_type n) const {
100 return _Self(current + n, Fn);
102 _Self& operator+= (difference_type n) { current += n; return *this; }
103 _Self operator- (difference_type n) const {
104 return _Self(current - n, Fn);
106 _Self& operator-= (difference_type n) { current -= n; return *this; }
107 reference operator[](difference_type n) const { return *(*this + n); }
109 inline bool operator!=(const _Self &X) const { return !operator==(X); }
110 inline bool operator==(const _Self &X) const { return current == X.current; }
111 inline bool operator< (const _Self &X) const { return current < X.current; }
113 inline difference_type operator-(const _Self &X) const {
114 return current - X.current;
118 template <class _Iterator, class Func>
119 inline mapped_iterator<_Iterator, Func>
120 operator+(typename mapped_iterator<_Iterator, Func>::difference_type N,
121 const mapped_iterator<_Iterator, Func>& X) {
122 return mapped_iterator<_Iterator, Func>(X.getCurrent() - N, X.getFunc());
126 // map_iterator - Provide a convenient way to create mapped_iterators, just like
127 // make_pair is useful for creating pairs...
129 template <class ItTy, class FuncTy>
130 inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) {
131 return mapped_iterator<ItTy, FuncTy>(I, F);
135 // next/prior - These functions unlike std::advance do not modify the
136 // passed iterator but return a copy.
138 // next(myIt) returns copy of myIt incremented once
139 // next(myIt, n) returns copy of myIt incremented n times
140 // prior(myIt) returns copy of myIt decremented once
141 // prior(myIt, n) returns copy of myIt decremented n times
143 template <typename ItTy, typename Dist>
144 inline ItTy next(ItTy it, Dist n)
150 template <typename ItTy>
151 inline ItTy next(ItTy it)
156 template <typename ItTy, typename Dist>
157 inline ItTy prior(ItTy it, Dist n)
159 std::advance(it, -n);
163 template <typename ItTy>
164 inline ItTy prior(ItTy it)
169 //===----------------------------------------------------------------------===//
170 // Extra additions to <utility>
171 //===----------------------------------------------------------------------===//
173 // tie - this function ties two objects and returns a temporary object
174 // that is assignable from a std::pair. This can be used to make code
175 // more readable when using values returned from functions bundled in
176 // a std::pair. Since an example is worth 1000 words:
178 // typedef std::map<int, int> Int2IntMap;
181 // Int2IntMap::iterator where;
183 // tie(where, inserted) = myMap.insert(std::make_pair(123,456));
192 template <typename T1, typename T2>
194 typedef T1 &first_type;
195 typedef T2 &second_type;
200 tier(first_type f, second_type s) : first(f), second(s) { }
201 tier& operator=(const std::pair<T1, T2>& p) {
209 template <typename T1, typename T2>
210 inline tier<T1, T2> tie(T1& f, T2& s) {
211 return tier<T1, T2>(f, s);
214 //===----------------------------------------------------------------------===//
215 // Extra additions for arrays
216 //===----------------------------------------------------------------------===//
218 /// Find where an array ends (for ending iterators)
219 /// This returns a pointer to the byte immediately
220 /// after the end of an array.
221 template<class T, std::size_t N>
222 inline T *array_endof(T (&x)[N]) {
226 /// Find the length of an array.
227 template<class T, std::size_t N>
228 inline size_t array_lengthof(T (&)[N]) {
232 /// array_pod_sort_comparator - This is helper function for array_pod_sort,
233 /// which just uses operator< on T.
235 static inline int array_pod_sort_comparator(const void *P1, const void *P2) {
236 if (*reinterpret_cast<const T*>(P1) < *reinterpret_cast<const T*>(P2))
238 if (*reinterpret_cast<const T*>(P2) < *reinterpret_cast<const T*>(P1))
243 /// get_array_pad_sort_comparator - This is an internal helper function used to
244 /// get type deduction of T right.
246 static int (*get_array_pad_sort_comparator(const T &))
247 (const void*, const void*) {
248 return array_pod_sort_comparator<T>;
252 /// array_pod_sort - This sorts an array with the specified start and end
253 /// extent. This is just like std::sort, except that it calls qsort instead of
254 /// using an inlined template. qsort is slightly slower than std::sort, but
255 /// most sorts are not performance critical in LLVM and std::sort has to be
256 /// template instantiated for each type, leading to significant measured code
257 /// bloat. This function should generally be used instead of std::sort where
260 /// This function assumes that you have simple POD-like types that can be
261 /// compared with operator< and can be moved with memcpy. If this isn't true,
262 /// you should use std::sort.
264 /// NOTE: If qsort_r were portable, we could allow a custom comparator and
265 /// default to std::less.
266 template<class IteratorTy>
267 static inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
268 // Don't dereference start iterator of empty sequence.
269 if (Start == End) return;
270 qsort(&*Start, End-Start, sizeof(*Start),
271 get_array_pad_sort_comparator(*Start));
274 template<class IteratorTy>
275 static inline void array_pod_sort(IteratorTy Start, IteratorTy End,
276 int (*Compare)(const void*, const void*)) {
277 // Don't dereference start iterator of empty sequence.
278 if (Start == End) return;
279 qsort(&*Start, End-Start, sizeof(*Start), Compare);
282 //===----------------------------------------------------------------------===//
283 // Extra additions to <algorithm>
284 //===----------------------------------------------------------------------===//
286 /// For a container of pointers, deletes the pointers and then clears the
288 template<typename Container>
289 void DeleteContainerPointers(Container &C) {
290 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
295 /// In a container of pairs (usually a map) whose second element is a pointer,
296 /// deletes the second elements and then clears the container.
297 template<typename Container>
298 void DeleteContainerSeconds(Container &C) {
299 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
304 } // End llvm namespace