llvm-6502/include/llvm/ADT/STLExtras.h
Benjamin Kramer 0d293e45b6 Provide basic type safety for array_pod_sort comparators.
This makes using array_pod_sort significantly safer. The implementation relies
on function pointer casting but that should be safe as we're dealing with void*
here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191175 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-22 14:09:50 +00:00

333 lines
10 KiB
C++

//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file 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 functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_STLEXTRAS_H
#define LLVM_ADT_STLEXTRAS_H
#include <cstddef> // for std::size_t
#include <cstdlib> // for qsort
#include <functional>
#include <iterator>
#include <utility> // for std::pair
namespace llvm {
//===----------------------------------------------------------------------===//
// Extra additions to <functional>
//===----------------------------------------------------------------------===//
template<class Ty>
struct identity : public std::unary_function<Ty, Ty> {
Ty &operator()(Ty &self) const {
return self;
}
const Ty &operator()(const Ty &self) const {
return self;
}
};
template<class Ty>
struct less_ptr : public std::binary_function<Ty, Ty, bool> {
bool operator()(const Ty* left, const Ty* right) const {
return *left < *right;
}
};
template<class Ty>
struct greater_ptr : public std::binary_function<Ty, Ty, bool> {
bool operator()(const Ty* left, const Ty* right) const {
return *right < *left;
}
};
// 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>
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 const RootIt &getCurrent() const { return current; }
inline const UnaryFunc &getFunc() const { return Fn; }
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, Fn);
}
_Self& operator+= (difference_type n) { current += n; return *this; }
_Self operator- (difference_type n) const {
return _Self(current - n, Fn);
}
_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, X.getFunc());
}
// 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)
{
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)
{
return --it;
}
//===----------------------------------------------------------------------===//
// 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
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);
}
/// \brief Function object to check whether the first component of a std::pair
/// compares less than the first component of another std::pair.
struct less_first {
template <typename T> bool operator()(const T &lhs, const T &rhs) const {
return lhs.first < rhs.first;
}
};
/// \brief Function object to check whether the second component of a std::pair
/// compares less than the second component of another std::pair.
struct less_second {
template <typename T> bool operator()(const T &lhs, const T &rhs) const {
return lhs.second < rhs.second;
}
};
//===----------------------------------------------------------------------===//
// Extra additions for arrays
//===----------------------------------------------------------------------===//
/// Find where an array ends (for ending iterators)
/// This returns a pointer to the byte immediately
/// after the end of an array.
template<class T, std::size_t N>
inline T *array_endof(T (&x)[N]) {
return x+N;
}
/// Find the length of an array.
template<class T, std::size_t N>
inline size_t array_lengthof(T (&)[N]) {
return N;
}
/// array_pod_sort_comparator - This is helper function for array_pod_sort,
/// which just uses operator< on T.
template<typename T>
inline int array_pod_sort_comparator(const void *P1, const void *P2) {
if (*reinterpret_cast<const T*>(P1) < *reinterpret_cast<const T*>(P2))
return -1;
if (*reinterpret_cast<const T*>(P2) < *reinterpret_cast<const T*>(P1))
return 1;
return 0;
}
/// get_array_pod_sort_comparator - This is an internal helper function used to
/// get type deduction of T right.
template<typename T>
inline int (*get_array_pod_sort_comparator(const T &))
(const void*, const void*) {
return array_pod_sort_comparator<T>;
}
/// array_pod_sort - This sorts an array with the specified start and end
/// extent. This is just like std::sort, except that it calls qsort instead of
/// using an inlined template. qsort is slightly slower than std::sort, but
/// most sorts are not performance critical in LLVM and std::sort has to be
/// template instantiated for each type, leading to significant measured code
/// bloat. This function should generally be used instead of std::sort where
/// possible.
///
/// This function assumes that you have simple POD-like types that can be
/// compared with operator< and can be moved with memcpy. If this isn't true,
/// you should use std::sort.
///
/// NOTE: If qsort_r were portable, we could allow a custom comparator and
/// default to std::less.
template<class IteratorTy>
inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
// Don't dereference start iterator of empty sequence.
if (Start == End) return;
qsort(&*Start, End-Start, sizeof(*Start),
get_array_pod_sort_comparator(*Start));
}
template <class IteratorTy>
inline void array_pod_sort(
IteratorTy Start, IteratorTy End,
int (*Compare)(
const typename std::iterator_traits<IteratorTy>::value_type *,
const typename std::iterator_traits<IteratorTy>::value_type *)) {
// Don't dereference start iterator of empty sequence.
if (Start == End) return;
qsort(&*Start, End - Start, sizeof(*Start),
reinterpret_cast<int (*)(const void *, const void *)>(Compare));
}
//===----------------------------------------------------------------------===//
// Extra additions to <algorithm>
//===----------------------------------------------------------------------===//
/// For a container of pointers, deletes the pointers and then clears the
/// container.
template<typename Container>
void DeleteContainerPointers(Container &C) {
for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
delete *I;
C.clear();
}
/// In a container of pairs (usually a map) whose second element is a pointer,
/// deletes the second elements and then clears the container.
template<typename Container>
void DeleteContainerSeconds(Container &C) {
for (typename Container::iterator I = C.begin(), E = C.end(); I != E; ++I)
delete I->second;
C.clear();
}
} // End llvm namespace
#endif