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#pragma once
#include "typetraits.h"
#include <cstring>
template <class T>
static constexpr const T& Min(const T& l, const T& r) {
return r < l ? r : l;
}
template <typename T, typename... Args>
static constexpr const T& Min(const T& a, const T& b, const Args&... args) {
return Min(a, Min(b, args...));
}
template <class T>
static constexpr const T& Max(const T& l, const T& r) {
return l < r ? r : l;
}
template <typename T, typename... Args>
static constexpr const T& Max(const T& a, const T& b, const Args&... args) {
return Max(a, Max(b, args...));
}
// replace with http://en.cppreference.com/w/cpp/algorithm/clamp in c++17
template <class T>
constexpr const T& ClampVal(const T& val, const T& min, const T& max) {
return val < min ? min : (max < val ? max : val);
}
template <typename T = double, typename... Args>
static T Mean(const Args&... other) noexcept {
const auto numArgs = sizeof...(other);
auto sum = T();
for (const auto& v : {other...}) {
sum += v;
}
return sum / numArgs;
}
template <class T>
static inline void Zero(T& t) noexcept {
memset((void*)&t, 0, sizeof(t));
}
/**
* Securely zero memory (compiler does not optimize this out)
*
* @param pointer void pointer to start of memory block to be zeroed
* @param count size of memory block to be zeroed (in bytes)
*/
void SecureZero(void* pointer, size_t count) noexcept;
/**
* Securely zero memory of given object (compiler does not optimize this out)
*
* @param t reference to object, which must be zeroed
*/
template <class T>
static inline void SecureZero(T& t) noexcept {
SecureZero((void*)&t, sizeof(t));
}
namespace NSwapCheck {
Y_HAS_MEMBER(swap);
Y_HAS_MEMBER(Swap);
template <class T, class = void>
struct TSwapSelector {
static inline void Swap(T& l, T& r) noexcept(std::is_nothrow_move_constructible<T>::value&&
std::is_nothrow_move_assignable<T>::value) {
T tmp(std::move(l));
l = std::move(r);
r = std::move(tmp);
}
};
template <class T>
struct TSwapSelector<T, std::enable_if_t<THasSwap<T>::value>> {
static inline void Swap(T& l, T& r) noexcept(noexcept(l.Swap(r))) {
l.Swap(r);
}
};
template <class T>
struct TSwapSelector<T, std::enable_if_t<THasswap<T>::value && !THasSwap<T>::value>> {
static inline void Swap(T& l, T& r) noexcept(noexcept(l.swap(r))) {
l.swap(r);
}
};
}
/*
* DoSwap better than ::Swap in member functions...
*/
template <class T>
static inline void DoSwap(T& l, T& r) noexcept(noexcept(NSwapCheck::TSwapSelector<T>::Swap(l, r))) {
NSwapCheck::TSwapSelector<T>::Swap(l, r);
}
template <bool b>
struct TNullTmpl {
template <class T>
operator T() const {
return (T)0;
}
};
using TNull = TNullTmpl<0>;
/*
* Class for zero-initialize padding bytes in derived classes
*/
template <typename TDerived>
class TZeroInit {
protected:
TZeroInit() {
// Actually, safe because this as TDerived is not initialized yet.
Zero(*static_cast<TDerived*>(this));
}
};
struct TIdentity {
template <class T>
constexpr decltype(auto) operator()(T&& x) const noexcept {
return std::forward<T>(x);
}
};
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