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generate compile-time prime table
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#include <array> | |
#include <iostream> | |
#include <type_traits> | |
#define ENABLER(cond) \ | |
typename std::enable_if<(cond), std::nullptr_t>::type = nullptr | |
template <typename T, T... N> | |
struct IntegerSequence; | |
template <typename T, class S> | |
struct IntegerSequenceTraits : std::false_type | |
{}; | |
template <typename T, T... N> | |
struct IntegerSequenceTraits<T, IntegerSequence<T, N...> > : std::true_type { | |
using type = IntegerSequence<T, N...>; | |
using value_type = typename type::value_type; | |
using size_type = typename type::size_type; | |
static constexpr size_type size() { return type::size(); } | |
}; | |
template <std::size_t... N> | |
using IndexSequence = IntegerSequence<std::size_t, N...>; | |
template <bool... B> | |
using BoolSequence = IntegerSequence<bool, B...>; | |
template <std::size_t From, std::size_t To, ENABLER(From <= To)> | |
struct MakeIndexSequenceHelper { | |
template <std::size_t Start, std::size_t Count> | |
struct Impl; | |
template <std::size_t Start, std::size_t Count> | |
struct Impl { | |
using Head = typename Impl<Start, (Count / 2)>::type; | |
using Tail = typename Impl<(Start + Count / 2), (Count - Count / 2)>::type; | |
using type = typename Head::template Join<Tail>::type; | |
}; | |
template <std::size_t Start> | |
struct Impl<Start, 1> { | |
using type = IndexSequence<Start>; | |
}; | |
template <std::size_t Start> | |
struct Impl<Start, 0> { | |
using type = IndexSequence<>; | |
}; | |
using type = typename Impl<From, (To - From)>::type; | |
}; | |
template <std::size_t From, std::size_t To> | |
using MakeIndexSequence = typename MakeIndexSequenceHelper<From, To>::type; | |
template <typename T, T N> | |
struct MakeIntegerSequenceHelper { | |
template <class S> | |
struct Impl; | |
template <std::size_t... I> | |
struct Impl<IndexSequence<I...> > | |
: IntegerSequence<T, (static_cast<T>(I))...> | |
{}; | |
using type = typename Impl<MakeIndexSequence<0, N> >::type; | |
}; | |
template <typename T, T N> | |
using MakeIntegerSequence = typename MakeIntegerSequenceHelper<T, N>::type; | |
template <class S> | |
struct AndAll; | |
template <bool C, bool... B> | |
struct AndAll<BoolSequence<C, B...> > { | |
static constexpr bool value = C && AndAll<BoolSequence<B...> >::value; | |
}; | |
template <> | |
struct AndAll<BoolSequence<> > { | |
static constexpr bool value = true; | |
}; | |
template <class S> | |
struct OrAll; | |
template <bool C, bool... B> | |
struct OrAll<BoolSequence<C, B...> > { | |
static constexpr bool value = C || OrAll<BoolSequence<B...> >::value; | |
}; | |
template <> | |
struct OrAll<BoolSequence<> > { | |
static constexpr bool value = false; | |
}; | |
template <typename T, T... N> | |
struct IntegerSequence { | |
using value_type = T; | |
using size_type = std::size_t; | |
using type = IntegerSequence; | |
static constexpr size_type size() { return sizeof...(N); } | |
static constexpr std::array<T, size()> make_array() { | |
return std::array<T, size()>{{N...}}; | |
} | |
static constexpr T at(size_type n) { return ((T[size()]){N...})[n]; } | |
template <template <T...> class S> | |
using Unpack = S<N...>; | |
template <typename U, U(f)(T)> | |
using Map = IntegerSequence<U, f(N)...>; | |
template <typename U, template <T> class F> | |
using ValueMap = IntegerSequence<U, F<N>::value...>; | |
template <T... M> | |
using Append = IntegerSequence<T, N..., M...>; | |
template <T... M> | |
using Prepend = IntegerSequence<T, M..., N...>; | |
template <class S, bool B, ENABLER(B)> | |
struct JoinHelper { | |
using type = typename S::template Prepend<N...>::type; | |
}; | |
template <class S> | |
using Join = typename JoinHelper<S, IntegerSequenceTraits<T, S>::value>::type; | |
template <size_type... I> | |
using Extract = IntegerSequence<T, at(I)...>; | |
template <size_type From, size_type To, ENABLER(From <= To)> | |
struct SliceHelper { | |
using Sequence = MakeIndexSequence<From, To>; | |
using type = typename Sequence::template Unpack<Extract>::type; | |
}; | |
template <size_type From, size_type To> | |
using Slice = typename SliceHelper<From, To>::type; | |
template <size_type Count> | |
struct Divide { | |
static constexpr auto count = Count < size() ? Count : size(); | |
using Head = typename Slice<0, count>::type; | |
using Tail = typename Slice<(size() - count), size()>::type; | |
}; | |
template <size_type Count> | |
using Head = typename Divide<Count>::Head; | |
template <size_type Count> | |
using Tail = typename Divide<Count>::Tail; | |
template <template <T> class F> | |
struct FilterHelper { | |
using E = IntegerSequence<T>; | |
template <class S> | |
struct Impl; | |
template <T... M> | |
struct Impl<IntegerSequence<T, M...> > { | |
using Sequence = IntegerSequence<T, M...>; | |
static constexpr auto size = Sequence::size(); | |
static constexpr auto half = size / 2; | |
using Head = typename Sequence::template Head<half>::type; | |
using Tail = typename Sequence::template Tail<(size - half)>::type; | |
using Left = typename Impl<Head>::type; | |
using Right = typename Impl<Tail>::type; | |
using type = typename Left::template Join<Right>::type; | |
}; | |
template <T M> | |
struct Impl<IntegerSequence<T, M> > { | |
using S = IntegerSequence<T, M>; | |
using type = typename std::conditional<F<M>::value, S, E>::type; | |
}; | |
using type = typename std::conditional< | |
(size() == 0), E, typename Impl<IntegerSequence>::type>::type; | |
}; | |
template <template <T> class F> | |
using Filter = typename FilterHelper<F>::type; | |
}; | |
constexpr bool is_even(int n) { | |
return n % 2 == 0; | |
} | |
constexpr int square(int n) { | |
return n * n; | |
} | |
// return a^b mod n | |
constexpr int mod_pow(int a, int b, int n) { | |
return (b == 0 ? 1 : | |
is_even(b) ? square(mod_pow(a, b / 2, n)) : | |
(a * mod_pow(a, b - 1, n))) % n; | |
} | |
constexpr int int_pow(int a, int b) { | |
return (b == 0 ? 1 : | |
is_even(b) ? square(int_pow(a, b / 2)) : | |
(a * int_pow(a, b - 1))); | |
} | |
// return (d, s) | |
// N == d * 2^s and d is odd | |
template <int N> | |
struct Factorize { | |
using Half = Factorize<(N / 2)>; | |
static constexpr int d = is_even(N) ? Half::d : N; | |
static constexpr int s = is_even(N) ? (Half::s + 1) : 0; | |
}; | |
template <> | |
struct Factorize<1> { | |
static constexpr int d = 1; | |
static constexpr int s = 0; | |
}; | |
// if true, n may be prime | |
// if false, n must be composite | |
// n == d * 2^s | |
// a is sample | |
template <int A, int N> | |
struct MillerTest { | |
template <int D, int S, bool B> | |
struct Impl { | |
struct Test1 { | |
static constexpr bool value = mod_pow(A, D, N) == 1; | |
}; | |
template <int R> | |
struct Test2 { | |
static constexpr bool value = mod_pow(A, D * int_pow(2, R), N) == N - 1; | |
}; | |
using Sequence = MakeIntegerSequence<int, S>; | |
using Conditions = typename Sequence::template ValueMap<bool, Test2>::type; | |
static constexpr bool value = Test1::value || OrAll<Conditions>::value; | |
}; | |
template <int D, int S> | |
struct Impl<D, S, false> { | |
static constexpr bool value = true; | |
}; | |
static constexpr auto D = Factorize<(N - 1)>::d; | |
static constexpr auto S = Factorize<(N - 1)>::s; | |
static constexpr bool value = Impl<D, S, (A < N)>::value; | |
}; | |
template <int N> | |
struct IsPrime { | |
struct ImplFalse { | |
static constexpr bool A2 = MillerTest<2, N>::value; | |
static constexpr bool A7 = MillerTest<7, N>::value; | |
static constexpr bool A61 = MillerTest<61, N>::value; | |
using Conditions = BoolSequence<A2, A7, A61>; | |
static constexpr bool value = AndAll<Conditions>::value; | |
}; | |
struct ImplTrue { | |
static constexpr bool value = N < 2 ? false : (N == 2); | |
}; | |
using Impl = typename std::conditional< | |
(N < 2 || is_even(N)), ImplTrue, ImplFalse>::type; | |
static constexpr bool value = Impl::value; | |
}; | |
template <typename T, class S> | |
struct SequenceForEach { | |
template <class, std::size_t> | |
struct Impl; | |
template <T M, T... N, std::size_t I> | |
struct Impl<IntegerSequence<T, M, N...>, I> { | |
template <typename F> | |
static void apply(F f) { | |
f(I, M); | |
Impl<IntegerSequence<T, N...>, (I + 1)>::apply(f); | |
} | |
}; | |
template <std::size_t I> | |
struct Impl<IntegerSequence<T>, I> { | |
template <typename F> | |
static void apply(F) {} | |
}; | |
template <typename F> | |
static void apply(F f) { | |
Impl<S, 0>::apply(f); | |
} | |
}; | |
template <typename... S> | |
struct VariadicPrint { | |
template <typename... T> | |
struct Impl; | |
template <typename V, typename U, typename... T> | |
struct Impl<V, U, T...> { | |
static void print(const V& v, const U& u, const T&... t) { | |
std::cout << v << ' '; | |
Impl<U, T...>::print(u, t...); | |
} | |
}; | |
template <typename T> | |
struct Impl<T> { | |
static void print(const T& t) { | |
std::cout << t << std::endl; | |
} | |
}; | |
static void print(const S&... s) { | |
Impl<S...>::print(s...); | |
} | |
}; | |
template <typename... T> | |
void print(const T&... t) { | |
VariadicPrint<T...>::print(t...); | |
} | |
template <typename T, T... N> | |
void print(IntegerSequence<T, N...>) { | |
const auto print = VariadicPrint<std::size_t, T>::print; | |
SequenceForEach<T, IntegerSequence<T, N...> >::apply(print); | |
} | |
int main() { | |
using Ints = MakeIntegerSequence<int, 10000>; | |
using Primes = Ints::template Filter<IsPrime>; | |
constexpr auto primes = Primes::make_array(); | |
for (auto&& p : primes) { | |
print(p); | |
} | |
} |
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