#ifndef ABSL_ALGORITHM_ALGORITHM_H_
#define ABSL_ALGORITHM_ALGORITHM_H_
#include <algorithm>
#include <iterator>
#include <type_traits>
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace algorithm_internal {
struct EqualTo {
template <typename T, typename U>
bool operator()(const T& a, const U& b) const {
return a == b;
}
};
template <typename InputIter1, typename InputIter2, typename Pred>
bool EqualImpl(InputIter1 first1, InputIter1 last1, InputIter2 first2,
InputIter2 last2, Pred pred, std::input_iterator_tag,
std::input_iterator_tag) {
while (true) {
if (first1 == last1) return first2 == last2;
if (first2 == last2) return false;
if (!pred(*first1, *first2)) return false;
++first1;
++first2;
}
}
template <typename InputIter1, typename InputIter2, typename Pred>
bool EqualImpl(InputIter1 first1, InputIter1 last1, InputIter2 first2,
InputIter2 last2, Pred&& pred, std::random_access_iterator_tag,
std::random_access_iterator_tag) {
return (last1 - first1 == last2 - first2) &&
std::equal(first1, last1, first2, std::forward<Pred>(pred));
}
template <typename InputIter1, typename InputIter2>
bool EqualImpl(InputIter1 first1, InputIter1 last1, InputIter2 first2,
InputIter2 last2, algorithm_internal::EqualTo ,
std::random_access_iterator_tag,
std::random_access_iterator_tag) {
return (last1 - first1 == last2 - first2) &&
std::equal(first1, last1, first2);
}
template <typename It>
It RotateImpl(It first, It middle, It last, std::true_type) {
return std::rotate(first, middle, last);
}
template <typename It>
It RotateImpl(It first, It middle, It last, std::false_type) {
std::rotate(first, middle, last);
return std::next(first, std::distance(middle, last));
}
}
template <typename InputIter1, typename InputIter2, typename Pred>
bool equal(InputIter1 first1, InputIter1 last1, InputIter2 first2,
InputIter2 last2, Pred&& pred) {
return algorithm_internal::EqualImpl(
first1, last1, first2, last2, std::forward<Pred>(pred),
typename std::iterator_traits<InputIter1>::iterator_category{},
typename std::iterator_traits<InputIter2>::iterator_category{});
}
template <typename InputIter1, typename InputIter2>
bool equal(InputIter1 first1, InputIter1 last1, InputIter2 first2,
InputIter2 last2) {
return absl::equal(first1, last1, first2, last2,
algorithm_internal::EqualTo{});
}
template <typename InputIterator, typename EqualityComparable>
bool linear_search(InputIterator first, InputIterator last,
const EqualityComparable& value) {
return std::find(first, last, value) != last;
}
template <typename ForwardIterator>
ForwardIterator rotate(ForwardIterator first, ForwardIterator middle,
ForwardIterator last) {
return algorithm_internal::RotateImpl(
first, middle, last,
std::is_same<decltype(std::rotate(first, middle, last)),
ForwardIterator>());
}
ABSL_NAMESPACE_END
}
#endif