| //===- STLExtras.h - Useful functions when working with the STL -*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file contains some templates that are useful if you are working with the |
| // STL at all. |
| // |
| // No library is required when using these functinons. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef SUPPORT_STLEXTRAS_H |
| #define SUPPORT_STLEXTRAS_H |
| |
| #include <functional> |
| #include <utility> // for std::pair |
| #include "Support/iterator" |
| |
| namespace llvm { |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <functional> |
| //===----------------------------------------------------------------------===// |
| |
| // bind_obj - Often times you want to apply the member function of an object |
| // as a unary functor. This macro is shorthand that makes it happen less |
| // verbosely. |
| // |
| // Example: |
| // struct Summer { void accumulate(int x); } |
| // vector<int> Numbers; |
| // Summer MyS; |
| // for_each(Numbers.begin(), Numbers.end(), |
| // bind_obj(&MyS, &Summer::accumulate)); |
| // |
| // TODO: When I get lots of extra time, convert this from an evil macro |
| // |
| #define bind_obj(OBJ, METHOD) std::bind1st(std::mem_fun(METHOD), OBJ) |
| |
| |
| // bitwise_or - This is a simple functor that applys operator| on its two |
| // arguments to get a boolean result. |
| // |
| template<class Ty> |
| struct bitwise_or : public std::binary_function<Ty, Ty, bool> { |
| bool operator()(const Ty& left, const Ty& right) const { |
| return left | right; |
| } |
| }; |
| |
| |
| // deleter - Very very very simple method that is used to invoke operator |
| // delete on something. It is used like this: |
| // |
| // for_each(V.begin(), B.end(), deleter<Interval>); |
| // |
| template <class T> |
| static inline void deleter(T *Ptr) { |
| delete Ptr; |
| } |
| |
| |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <iterator> |
| //===----------------------------------------------------------------------===// |
| |
| // mapped_iterator - This is a simple iterator adapter that causes a function to |
| // be dereferenced whenever operator* is invoked on the iterator. |
| // |
| template <class RootIt, class UnaryFunc> |
| class mapped_iterator { |
| RootIt current; |
| UnaryFunc Fn; |
| public: |
| typedef typename std::iterator_traits<RootIt>::iterator_category |
| iterator_category; |
| typedef typename std::iterator_traits<RootIt>::difference_type |
| difference_type; |
| typedef typename UnaryFunc::result_type value_type; |
| |
| typedef void pointer; |
| //typedef typename UnaryFunc::result_type *pointer; |
| typedef void reference; // Can't modify value returned by fn |
| |
| typedef RootIt iterator_type; |
| typedef mapped_iterator<RootIt, UnaryFunc> _Self; |
| |
| inline RootIt &getCurrent() const { return current; } |
| |
| inline explicit mapped_iterator(const RootIt &I, UnaryFunc F) |
| : current(I), Fn(F) {} |
| inline mapped_iterator(const mapped_iterator &It) |
| : current(It.current), Fn(It.Fn) {} |
| |
| inline value_type operator*() const { // All this work to do this |
| return Fn(*current); // little change |
| } |
| |
| _Self& operator++() { ++current; return *this; } |
| _Self& operator--() { --current; return *this; } |
| _Self operator++(int) { _Self __tmp = *this; ++current; return __tmp; } |
| _Self operator--(int) { _Self __tmp = *this; --current; return __tmp; } |
| _Self operator+ (difference_type n) const { return _Self(current + n); } |
| _Self& operator+= (difference_type n) { current += n; return *this; } |
| _Self operator- (difference_type n) const { return _Self(current - n); } |
| _Self& operator-= (difference_type n) { current -= n; return *this; } |
| reference operator[](difference_type n) const { return *(*this + n); } |
| |
| inline bool operator!=(const _Self &X) const { return !operator==(X); } |
| inline bool operator==(const _Self &X) const { return current == X.current; } |
| inline bool operator< (const _Self &X) const { return current < X.current; } |
| |
| inline difference_type operator-(const _Self &X) const { |
| return current - X.current; |
| } |
| }; |
| |
| template <class _Iterator, class Func> |
| inline mapped_iterator<_Iterator, Func> |
| operator+(typename mapped_iterator<_Iterator, Func>::difference_type N, |
| const mapped_iterator<_Iterator, Func>& X) { |
| return mapped_iterator<_Iterator, Func>(X.getCurrent() - N); |
| } |
| |
| |
| // map_iterator - Provide a convenient way to create mapped_iterators, just like |
| // make_pair is useful for creating pairs... |
| // |
| template <class ItTy, class FuncTy> |
| inline mapped_iterator<ItTy, FuncTy> map_iterator(const ItTy &I, FuncTy F) { |
| return mapped_iterator<ItTy, FuncTy>(I, F); |
| } |
| |
| |
| // next/prior - These functions unlike std::advance do not modify the |
| // passed iterator but return a copy. |
| // |
| // next(myIt) returns copy of myIt incremented once |
| // next(myIt, n) returns copy of myIt incremented n times |
| // prior(myIt) returns copy of myIt decremented once |
| // prior(myIt, n) returns copy of myIt decremented n times |
| |
| template <typename ItTy, typename Dist> |
| inline ItTy next(ItTy it, Dist n) |
| { |
| std::advance(it, n); |
| return it; |
| } |
| |
| template <typename ItTy> |
| inline ItTy next(ItTy it) |
| { |
| std::advance(it, 1); |
| return it; |
| } |
| |
| template <typename ItTy, typename Dist> |
| inline ItTy prior(ItTy it, Dist n) |
| { |
| std::advance(it, -n); |
| return it; |
| } |
| |
| template <typename ItTy> |
| inline ItTy prior(ItTy it) |
| { |
| std::advance(it, -1); |
| return it; |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <algorithm> |
| //===----------------------------------------------------------------------===// |
| |
| // apply_until - Apply a functor to a sequence continually, unless the |
| // functor returns true. Return true if the functor returned true, return false |
| // if the functor never returned true. |
| // |
| template <class InputIt, class Function> |
| bool apply_until(InputIt First, InputIt Last, Function Func) { |
| for ( ; First != Last; ++First) |
| if (Func(*First)) return true; |
| return false; |
| } |
| |
| |
| // reduce - Reduce a sequence values into a single value, given an initial |
| // value and an operator. |
| // |
| template <class InputIt, class Function, class ValueType> |
| ValueType reduce(InputIt First, InputIt Last, Function Func, ValueType Value) { |
| for ( ; First != Last; ++First) |
| Value = Func(*First, Value); |
| return Value; |
| } |
| |
| #if 1 // This is likely to be more efficient |
| |
| // reduce_apply - Reduce the result of applying a function to each value in a |
| // sequence, given an initial value, an operator, a function, and a sequence. |
| // |
| template <class InputIt, class Function, class ValueType, class TransFunc> |
| inline ValueType reduce_apply(InputIt First, InputIt Last, Function Func, |
| ValueType Value, TransFunc XForm) { |
| for ( ; First != Last; ++First) |
| Value = Func(XForm(*First), Value); |
| return Value; |
| } |
| |
| #else // This is arguably more elegant |
| |
| // reduce_apply - Reduce the result of applying a function to each value in a |
| // sequence, given an initial value, an operator, a function, and a sequence. |
| // |
| template <class InputIt, class Function, class ValueType, class TransFunc> |
| inline ValueType reduce_apply2(InputIt First, InputIt Last, Function Func, |
| ValueType Value, TransFunc XForm) { |
| return reduce(map_iterator(First, XForm), map_iterator(Last, XForm), |
| Func, Value); |
| } |
| #endif |
| |
| |
| // reduce_apply_bool - Reduce the result of applying a (bool returning) function |
| // to each value in a sequence. All of the bools returned by the mapped |
| // function are bitwise or'd together, and the result is returned. |
| // |
| template <class InputIt, class Function> |
| inline bool reduce_apply_bool(InputIt First, InputIt Last, Function Func) { |
| return reduce_apply(First, Last, bitwise_or<bool>(), false, Func); |
| } |
| |
| |
| // map - This function maps the specified input sequence into the specified |
| // output iterator, applying a unary function in between. |
| // |
| template <class InIt, class OutIt, class Functor> |
| inline OutIt mapto(InIt Begin, InIt End, OutIt Dest, Functor F) { |
| return copy(map_iterator(Begin, F), map_iterator(End, F), Dest); |
| } |
| |
| |
| //===----------------------------------------------------------------------===// |
| // Extra additions to <utility> |
| //===----------------------------------------------------------------------===// |
| |
| // tie - this function ties two objects and returns a temporary object |
| // that is assignable from a std::pair. This can be used to make code |
| // more readable when using values returned from functions bundled in |
| // a std::pair. Since an example is worth 1000 words: |
| // |
| // typedef std::map<int, int> Int2IntMap; |
| // |
| // Int2IntMap myMap; |
| // Int2IntMap::iterator where; |
| // bool inserted; |
| // tie(where, inserted) = myMap.insert(std::make_pair(123,456)); |
| // |
| // if (inserted) |
| // // do stuff |
| // else |
| // // do other stuff |
| |
| namespace |
| { |
| template <typename T1, typename T2> |
| struct tier { |
| typedef T1 &first_type; |
| typedef T2 &second_type; |
| |
| first_type first; |
| second_type second; |
| |
| tier(first_type f, second_type s) : first(f), second(s) { } |
| tier& operator=(const std::pair<T1, T2>& p) { |
| first = p.first; |
| second = p.second; |
| return *this; |
| } |
| }; |
| } |
| |
| template <typename T1, typename T2> |
| inline tier<T1, T2> tie(T1& f, T2& s) { |
| return tier<T1, T2>(f, s); |
| } |
| |
| } // End llvm namespace |
| |
| #endif |