forked from OctaForge/libostd
290 lines
7.5 KiB
C++
290 lines
7.5 KiB
C++
/* Utilities for OctaSTD.
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*
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* This file is part of OctaSTD. See COPYING.md for futher information.
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*/
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#ifndef OCTA_UTILITY_H
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#define OCTA_UTILITY_H
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#include <stddef.h>
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#include "octa/type_traits.h"
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namespace octa {
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/* move */
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template<typename T>
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static inline constexpr RemoveReference<T> &&move(T &&v) {
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return static_cast<RemoveReference<T> &&>(v);
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}
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/* forward */
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template<typename T>
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static inline constexpr T &&forward(RemoveReference<T> &v) {
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return static_cast<T &&>(v);
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}
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template<typename T>
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static inline constexpr T &&forward(RemoveReference<T> &&v) {
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return static_cast<T &&>(v);
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}
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/* exchange */
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template<typename T, typename U = T>
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T exchange(T &v, U &&nv) {
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T old = move(v);
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v = forward<U>(nv);
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return old;
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}
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/* declval */
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template<typename T> AddRvalueReference<T> declval();
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/* swap */
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namespace detail {
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template<typename T>
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struct SwapTest {
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template<typename U, void (U::*)(U &)> struct Test {};
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template<typename U> static char test(Test<U, &U::swap> *);
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template<typename U> static int test(...);
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static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
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};
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template<typename T> inline void swap(T &a, T &b, EnableIf<
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octa::detail::SwapTest<T>::value, bool
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> = true) {
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a.swap(b);
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}
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template<typename T> inline void swap(T &a, T &b, EnableIf<
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!octa::detail::SwapTest<T>::value, bool
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> = true) {
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T c(octa::move(a));
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a = octa::move(b);
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b = octa::move(c);
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}
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}
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template<typename T> void swap(T &a, T &b) {
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octa::detail::swap(a, b);
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}
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template<typename T, octa::Size N> void swap(T (&a)[N], T (&b)[N]) {
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for (octa::Size i = 0; i < N; ++i) {
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octa::swap(a[i], b[i]);
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}
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}
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/* pair */
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template<typename T, typename U>
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struct Pair {
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T first;
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U second;
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Pair() = default;
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~Pair() = default;
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Pair(const Pair &) = default;
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Pair(Pair &&) = default;
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Pair(const T &x, const U &y): first(x), second(y) {}
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template<typename TT, typename UU>
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Pair(TT &&x, UU &&y):
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first(octa::forward<TT>(x)), second(octa::forward<UU>(y)) {}
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template<typename TT, typename UU>
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Pair(const Pair<TT, UU> &v): first(v.first), second(v.second) {}
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template<typename TT, typename UU>
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Pair(Pair<TT, UU> &&v):
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first(octa::move(v.first)), second(octa::move(v.second)) {}
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Pair &operator=(const Pair &v) {
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first = v.first;
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second = v.second;
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return *this;
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}
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template<typename TT, typename UU>
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Pair &operator=(const Pair<TT, UU> &v) {
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first = v.first;
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second = v.second;
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return *this;
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}
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Pair &operator=(Pair &&v) {
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first = octa::move(v.first);
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second = octa::move(v.second);
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return *this;
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}
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template<typename TT, typename UU>
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Pair &operator=(Pair<TT, UU> &&v) {
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first = octa::forward<TT>(v.first);
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second = octa::forward<UU>(v.second);
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return *this;
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}
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void swap(Pair &v) {
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octa::swap(first, v.first);
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octa::swap(second, v.second);
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}
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};
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template<typename T> struct ReferenceWrapper;
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namespace detail {
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template<typename T>
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struct MakePairRetBase {
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using Type = T;
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};
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template<typename T>
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struct MakePairRetBase<ReferenceWrapper<T>> {
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using Type = T &;
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};
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template<typename T>
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struct MakePairRet {
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using Type = typename octa::detail::MakePairRetBase<octa::Decay<T>>::Type;
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};
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} /* namespace detail */
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template<typename T, typename U>
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Pair<typename octa::detail::MakePairRet<T>::Type,
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typename octa::detail::MakePairRet<U>::Type
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> make_pair(T &&a, U &&b) {
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return Pair<typename octa::detail::MakePairRet<T>::Type,
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typename octa::detail::MakePairRet<U>::Type
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>(forward<T>(a), forward<U>(b));;
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}
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namespace detail {
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template<typename T, typename U,
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bool = octa::IsSame<octa::RemoveCv<T>, octa::RemoveCv<U>>::value,
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bool = octa::IsEmpty<T>::value,
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bool = octa::IsEmpty<U>::value
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> struct CompressedPairSwitch;
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/* neither empty */
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template<typename T, typename U, bool Same>
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struct CompressedPairSwitch<T, U, Same, false, false> { enum { value = 0 }; };
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/* first empty */
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template<typename T, typename U, bool Same>
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struct CompressedPairSwitch<T, U, Same, true, false> { enum { value = 1 }; };
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/* second empty */
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template<typename T, typename U, bool Same>
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struct CompressedPairSwitch<T, U, Same, false, true> { enum { value = 2 }; };
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/* both empty, not the same */
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template<typename T, typename U>
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struct CompressedPairSwitch<T, U, false, true, true> { enum { value = 3 }; };
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/* both empty and same */
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template<typename T, typename U>
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struct CompressedPairSwitch<T, U, true, true, true> { enum { value = 1 }; };
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template<typename T, typename U, octa::Size = CompressedPairSwitch<T, U>::value>
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struct CompressedPairBase;
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template<typename T, typename U>
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struct CompressedPairBase<T, U, 0> {
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T p_first;
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U p_second;
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CompressedPairBase(T a, U b): p_first(octa::forward<T>(a)),
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p_second(octa::forward<U>(b)) {}
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T &first() { return p_first; }
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const T &first() const { return p_first; }
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U &second() { return p_second; }
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const U &second() const { return p_second; }
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void swap(CompressedPairBase &v) {
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octa::swap(p_first, v.p_first);
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octa::swap(p_second, v.p_second);
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}
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};
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template<typename T, typename U>
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struct CompressedPairBase<T, U, 1>: T {
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U p_second;
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CompressedPairBase(T a, U b): T(octa::forward<T>(a)),
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p_second(octa::forward<U>(b)) {}
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T &first() { return *this; }
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const T &first() const { return *this; }
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U &second() { return p_second; }
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const U &second() const { return p_second; }
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void swap(CompressedPairBase &v) {
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octa::swap(p_second, v.p_second);
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}
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};
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template<typename T, typename U>
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struct CompressedPairBase<T, U, 2>: U {
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T p_first;
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CompressedPairBase(T a, U b): U(octa::forward<U>(b)),
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p_first(octa::forward<T>(a)) {}
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T &first() { return p_first; }
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const T &first() const { return p_first; }
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U &second() { return *this; }
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const U &second() const { return *this; }
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void swap(CompressedPairBase &v) {
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octa::swap(p_first, v.p_first);
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}
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};
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template<typename T, typename U>
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struct CompressedPairBase<T, U, 3>: T, U {
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CompressedPairBase(T a, U b): T(octa::forward<T>(a)),
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U(octa::forward<U>(b)) {}
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T &first() { return *this; }
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const T &first() const { return *this; }
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U &second() { return *this; }
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const U &second() const { return *this; }
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void swap(CompressedPairBase &) {}
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};
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template<typename T, typename U>
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struct CompressedPair: CompressedPairBase<T, U> {
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typedef CompressedPairBase<T, U> Base;
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CompressedPair(T a, U b): Base(octa::forward<T>(a),
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octa::forward<U>(b)) {}
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T &first() { return Base::first(); }
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const T &first() const { return Base::first(); }
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U &second() { return Base::second(); }
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const U &second() const { return Base::second(); }
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void swap(CompressedPair &v) {
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Base::swap(v);
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}
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};
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} /* namespace detail */
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} /* namespace octa */
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#endif |