1//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file contains some templates that are useful if you are working with the 11// STL at all. 12// 13// No library is required when using these functions. 14// 15//===----------------------------------------------------------------------===// 16 17#ifndef LLVM_ADT_STLEXTRAS_H 18#define LLVM_ADT_STLEXTRAS_H 19 20#include <cstddef> // for std::size_t 21#include <cstdlib> // for qsort 22#include <functional> 23#include <iterator> 24#include <utility> // for std::pair 25 26namespace llvm { 27 28//===----------------------------------------------------------------------===// 29// Extra additions to <functional> 30//===----------------------------------------------------------------------===// 31 32template<class Ty> 33struct identity : public std::unary_function<Ty, Ty> { 34 Ty &operator()(Ty &self) const { 35 return self; 36 } 37 const Ty &operator()(const Ty &self) const { 38 return self; 39 } 40}; 41 42template<class Ty> 43struct less_ptr : public std::binary_function<Ty, Ty, bool> { 44 bool operator()(const Ty* left, const Ty* right) const { 45 return *left < *right; 46 } 47}; 48 49template<class Ty> 50struct greater_ptr : public std::binary_function<Ty, Ty, bool> { 51 bool operator()(const Ty* left, const Ty* right) const { 52 return *right < *left; 53 } 54}; 55 56// deleter - Very very very simple method that is used to invoke operator 57// delete on something. It is used like this: 58// 59// for_each(V.begin(), B.end(), deleter<Interval>); 60// 61template <class T> 62inline void deleter(T *Ptr) { 63 delete Ptr; 64} 65 66 67 68//===----------------------------------------------------------------------===// 69// Extra additions to <iterator> 70//===----------------------------------------------------------------------===// 71 72// mapped_iterator - This is a simple iterator adapter that causes a function to 73// be dereferenced whenever operator* is invoked on the iterator. 74// 75template <class RootIt, class UnaryFunc> 76class mapped_iterator { 77 RootIt current; 78 UnaryFunc Fn; 79public: 80 typedef typename std::iterator_traits<RootIt>::iterator_category 81 iterator_category; 82 typedef typename std::iterator_traits<RootIt>::difference_type 83 difference_type; 84 typedef typename UnaryFunc::result_type value_type; 85 86 typedef void pointer; 87 //typedef typename UnaryFunc::result_type *pointer; 88 typedef void reference; // Can't modify value returned by fn 89 90 typedef RootIt iterator_type; 91 typedef mapped_iterator<RootIt, UnaryFunc> _Self; 92 93 inline const RootIt &getCurrent() const { return current; } 94 inline const UnaryFunc &getFunc() const { return Fn; } 95 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) {} 100 101 inline value_type operator*() const { // All this work to do this 102 return Fn(*current); // little change 103 } 104 105 _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); 111 } 112 _Self& operator+= (difference_type n) { current += n; return *this; } 113 _Self operator- (difference_type n) const { 114 return _Self(current - n, Fn); 115 } 116 _Self& operator-= (difference_type n) { current -= n; return *this; } 117 reference operator[](difference_type n) const { return *(*this + n); } 118 119 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; } 122 123 inline difference_type operator-(const _Self &X) const { 124 return current - X.current; 125 } 126}; 127 128template <class _Iterator, class Func> 129inline mapped_iterator<_Iterator, Func> 130operator+(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()); 133} 134 135 136// map_iterator - Provide a convenient way to create mapped_iterators, just like 137// make_pair is useful for creating pairs... 138// 139template <class ItTy, class FuncTy> 140inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) { 141 return mapped_iterator<ItTy, FuncTy>(I, F); 142} 143 144 145// next/prior - These functions unlike std::advance do not modify the 146// passed iterator but return a copy. 147// 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 152 153template <typename ItTy, typename Dist> 154inline ItTy next(ItTy it, Dist n) 155{ 156 std::advance(it, n); 157 return it; 158} 159 160template <typename ItTy> 161inline ItTy next(ItTy it) 162{ 163 return ++it; 164} 165 166template <typename ItTy, typename Dist> 167inline ItTy prior(ItTy it, Dist n) 168{ 169 std::advance(it, -n); 170 return it; 171} 172 173template <typename ItTy> 174inline ItTy prior(ItTy it) 175{ 176 return --it; 177} 178 179//===----------------------------------------------------------------------===// 180// Extra additions to <utility> 181//===----------------------------------------------------------------------===// 182 183// 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: 187// 188// typedef std::map<int, int> Int2IntMap; 189// 190// Int2IntMap myMap; 191// Int2IntMap::iterator where; 192// bool inserted; 193// tie(where, inserted) = myMap.insert(std::make_pair(123,456)); 194// 195// if (inserted) 196// // do stuff 197// else 198// // do other stuff 199template <typename T1, typename T2> 200struct tier { 201 typedef T1 &first_type; 202 typedef T2 &second_type; 203 204 first_type first; 205 second_type second; 206 207 tier(first_type f, second_type s) : first(f), second(s) { } 208 tier& operator=(const std::pair<T1, T2>& p) { 209 first = p.first; 210 second = p.second; 211 return *this; 212 } 213}; 214 215template <typename T1, typename T2> 216inline tier<T1, T2> tie(T1& f, T2& s) { 217 return tier<T1, T2>(f, s); 218} 219 220//===----------------------------------------------------------------------===// 221// Extra additions for arrays 222//===----------------------------------------------------------------------===// 223 224/// Find where an array ends (for ending iterators) 225/// This returns a pointer to the byte immediately 226/// after the end of an array. 227template<class T, std::size_t N> 228inline T *array_endof(T (&x)[N]) { 229 return x+N; 230} 231 232/// Find the length of an array. 233template<class T, std::size_t N> 234inline size_t array_lengthof(T (&)[N]) { 235 return N; 236} 237 238/// array_pod_sort_comparator - This is helper function for array_pod_sort, 239/// which just uses operator< on T. 240template<typename T> 241inline int array_pod_sort_comparator(const void *P1, const void *P2) { 242 if (*reinterpret_cast<const T*>(P1) < *reinterpret_cast<const T*>(P2)) 243 return -1; 244 if (*reinterpret_cast<const T*>(P2) < *reinterpret_cast<const T*>(P1)) 245 return 1; 246 return 0; 247} 248 249/// get_array_pad_sort_comparator - This is an internal helper function used to 250/// get type deduction of T right. 251template<typename T> 252inline int (*get_array_pad_sort_comparator(const T &)) 253 (const void*, const void*) { 254 return array_pod_sort_comparator<T>; 255} 256 257 258/// 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 264/// possible. 265/// 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. 269/// 270/// NOTE: If qsort_r were portable, we could allow a custom comparator and 271/// default to std::less. 272template<class IteratorTy> 273inline 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)); 278} 279 280template<class IteratorTy> 281inline 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); 286} 287 288//===----------------------------------------------------------------------===// 289// Extra additions to <algorithm> 290//===----------------------------------------------------------------------===// 291 292/// For a container of pointers, deletes the pointers and then clears the 293/// container. 294template<typename Container> 295void DeleteContainerPointers(Container &C) { 296 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I) 297 delete *I; 298 C.clear(); 299} 300 301/// In a container of pairs (usually a map) whose second element is a pointer, 302/// deletes the second elements and then clears the container. 303template<typename Container> 304void DeleteContainerSeconds(Container &C) { 305 for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I) 306 delete I->second; 307 C.clear(); 308} 309 310} // End llvm namespace 311 312#endif 313