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343 | #pragma once
#include <cmath><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <cstdint><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <vector><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <valarray><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <ranges><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <bit><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include "internal/dev_env.hpp"
#include "snippet/iterations.hpp"
#include "internal/types.hpp"
#include "internal/iterator.hpp"
#include "numeric/arithmetic.hpp"
#include "numeric/bit.hpp"
#include "numeric/limits.hpp"
namespace uni {
// Thanks to: https://qiita.com/peria/items/e0ab38f95d16a5f7cc58
template<class T>
struct prime_enumerator : std::ranges::view_interface<prime_enumerator<T>> {
using value_type = T;
using size_type = internal::size_t;
protected:
using impl_type = std::uint32_t;
impl_type _n = 0;
using small_bit_type = std::uint8_t;
using large_bit_type = std::uint64_t;
static constexpr impl_type SEGMENT_SIZE = 1'000'000;
static constexpr impl_type MOD30[8] = { 1, 7, 11, 13, 17, 19, 23, 29 };
static constexpr small_bit_type MASK[8][8] = {
{ 0xfe, 0xfd, 0xfb, 0xf7, 0xef, 0xdf, 0xbf, 0x7f },
{ 0xfd, 0xdf, 0xef, 0xfe, 0x7f, 0xf7, 0xfb, 0xbf },
{ 0xfb, 0xef, 0xfe, 0xbf, 0xfd, 0x7f, 0xf7, 0xdf },
{ 0xf7, 0xfe, 0xbf, 0xdf, 0xfb, 0xfd, 0x7f, 0xef },
{ 0xef, 0x7f, 0xfd, 0xfb, 0xdf, 0xbf, 0xfe, 0xf7 },
{ 0xdf, 0xf7, 0x7f, 0xfd, 0xbf, 0xfe, 0xef, 0xfb },
{ 0xbf, 0xfb, 0xf7, 0x7f, 0xfe, 0xef, 0xdf, 0xfd },
{ 0x7f, 0xbf, 0xdf, 0xef, 0xf7, 0xfb, 0xfd, 0xfe },
};
static constexpr impl_type C1[8] = { 6, 4, 2, 4, 2, 4, 6, 2 };
static constexpr impl_type C0[8][8] = {
{ 0, 0, 0, 0, 0, 0, 0, 1 }, { 1, 1, 1, 0, 1, 1, 1, 1 },
{ 2, 2, 0, 2, 0, 2, 2, 1 }, { 3, 1, 1, 2, 1, 1, 3, 1 },
{ 3, 3, 1, 2, 1, 3, 3, 1 }, { 4, 2, 2, 2, 2, 2, 4, 1 },
{ 5, 3, 1, 4, 1, 3, 5, 1 }, { 6, 4, 2, 4, 2, 4, 6, 1 },
};
size_type _size;
impl_type _sqrt_n = 0, _sqrt_ni = 0, _quart_n = 0;
std::valarray<small_bit_type> _small;
std::valarray<large_bit_type> _large;
std::vector<impl_type> _indecies;
small_bit_type* _flag = nullptr;
inline void _init(const value_type n, const impl_type size) noexcept(NO_EXCEPT) {
const size_type blocks = (size + 7) >> 3;
this->_large.resize(blocks + 1, ~0UL);
this->_flag = reinterpret_cast<small_bit_type*>(&(this->_large[0]));
this->_flag[0] = 0xfe;
value_type r = n % 30;
if(r <= 1) this->_flag[size - 1] = 0x0;
else if(r <= 7) this->_flag[size - 1] = 0x1;
else if(r <= 11) this->_flag[size - 1] = 0x3;
else if(r <= 13) this->_flag[size - 1] = 0x7;
else if(r <= 17) this->_flag[size - 1] = 0xf;
else if(r <= 19) this->_flag[size - 1] = 0x1f;
else if(r <= 23) this->_flag[size - 1] = 0x3f;
else if(r <= 29) this->_flag[size - 1] = 0x7f;
if(n < 30) this->_flag[0] &= 0xfe;
this->_large[blocks - 1] <<= 64 - ((size & 7) << 3);
this->_large[blocks - 1] >>= 64 - ((size & 7) << 3);
this->_large[blocks] = 0;
// for(auto x : this->_large) debug(std::bitset<64>(x));
}
inline void _gen_small() noexcept(NO_EXCEPT) {
const impl_type quart_ni = this->_quart_n / 30 + 1;
this->_small.resize(this->_sqrt_ni, 0xff);
this->_small[0] = 0xfe;
REP(i, quart_ni) {
for(small_bit_type flags = this->_small[i]; flags; flags &= flags - 1) {
const int ibit = lowest_bit_pos(flags);
const impl_type m = prime_enumerator::MOD30[ibit];
const impl_type pm = 30 * i + 2 * m;
for(
impl_type j = i * pm + (m * m) / 30, k = ibit;
j < this->_sqrt_ni;
j += i * prime_enumerator::C1[k] + prime_enumerator::C0[ibit][k], k = (k + 1) & 7
) {
this->_small[j] &= prime_enumerator::MASK[ibit][k];
}
}
}
REP(i, this->_sqrt_ni) {
for(small_bit_type flags = this->_small[i]; flags; flags &= flags - 1) {
const int ibit = lowest_bit_pos(flags);
const impl_type m = prime_enumerator::MOD30[ibit];
impl_type j = i * (30 * i + 2 * m) + (m * m) / 30;
this->_indecies.emplace_back(((j + prime_enumerator::SEGMENT_SIZE) << 3) | ibit);
}
}
}
inline void _gen_core(small_bit_type *const flags, const impl_type size) noexcept(NO_EXCEPT) {
auto p_index = this->_indecies.begin();
REP(i, this->_sqrt_ni) {
for(small_bit_type primes = this->_small[i]; primes; primes &= primes - 1) {
const int ibit = lowest_bit_pos(primes);
impl_type j = (*p_index >> 3) - prime_enumerator::SEGMENT_SIZE;
impl_type k = *p_index & 7;
for(; j < size; j += i * prime_enumerator::C1[k] + prime_enumerator::C0[ibit][k], k = (k + 1) & 7) {
flags[j] &= prime_enumerator::MASK[ibit][k];
}
*p_index = ((j << 3) | k);
++p_index;
}
}
}
using iterator_interface = internal::bidirectional_iterator_interface<const value_type>;
public:
struct iterator;
using const_iterator = iterator;
prime_enumerator() noexcept {};
prime_enumerator(const value_type n) noexcept(NO_EXCEPT) : _n(n) {<--- Struct 'prime_enumerator' has a constructor with 1 argument that is not explicit. [+]Struct 'prime_enumerator' has a constructor with 1 argument that is not explicit. Such, so called "Converting constructors", should in general be explicit for type safety reasons as that prevents unintended implicit conversions.
assert(n >= 0);
assert(std::endian::native == std::endian::little);
this->_sqrt_n = static_cast<impl_type>(sqrt_ceil(this->_n + 1));
this->_sqrt_ni = this->_sqrt_n / 30 + 1;
this->_quart_n = static_cast<impl_type>(sqrt_ceil(this->_sqrt_n));
this->_gen_small();
impl_type size = (this->_n + 1) / 30 + 1;<--- Shadow variable
this->_init(this->_n + 1, size);
for(small_bit_type* seg = this->_flag; ; seg += prime_enumerator::SEGMENT_SIZE) {
if(size < prime_enumerator::SEGMENT_SIZE) {
this->_gen_core(seg, size);
break;
};
this->_gen_core(seg, prime_enumerator::SEGMENT_SIZE);
size -= prime_enumerator::SEGMENT_SIZE;
}
this->_size = (this->_n >= 2) + (this->_n >= 3) + (this->_n >= 5);
for(const large_bit_type f : this->_large) this->_size += std::popcount(f);
}
inline size_type size() const noexcept(NO_EXCEPT) { return this->_size; }<--- Shadowed declaration
inline size_type count(const T x) const noexcept(NO_EXCEPT) {
assert(0 <= x and x <= this->_n);
size_type res = (x >= 2) + (x >= 3) + (x >= 5);
T count = 0;
constexpr int large_bit_width = std::numeric_limits<large_bit_type>::digits;
constexpr int large_bit_size = (30 * large_bit_width) >> 3;
for(const large_bit_type f : this->_large) {
if(count + large_bit_size > x) {
REP(i, large_bit_width) {
if(count + prime_enumerator::MOD30[i & 7] > x) break;
if((f >> i) & 1) res++;<--- Prefer prefix ++/-- operators for non-primitive types. [+]Prefix ++/-- operators should be preferred for non-primitive types. Pre-increment/decrement can be more efficient than post-increment/decrement. Post-increment/decrement usually involves keeping a copy of the previous value around and adds a little extra code.
if(((i + 1) & 7) == 0) count += 30;
}
break;
}
res += std::popcount(f);
count += large_bit_size;
}
return res;
}
inline size_type count(const T l, const T r) const noexcept(NO_EXCEPT) {
assert(l <= r);
return this->count(r) - this->count(l - 1);
}
inline bool is_prime(const T v) const noexcept(NO_EXCEPT) {
assert(0 <= v and v <= this->_n);
if(v == 0 or v == 1) return false;
if(v == 2 or v == 3 or v == 5) return true;
if((v & 1) == 0 or v % 3 == 0 or v % 5 == 0) return false;
REP(i, 8) {
if(prime_enumerator::MOD30[i] == v % 30) {
return static_cast<bool>((this->_flag[v / 30] >> i) & 1);
}
}
assert(false);
}
inline auto begin() const noexcept(NO_EXCEPT) { return iterator(this, 0); }
inline auto end() const noexcept(NO_EXCEPT) { return iterator(this, -1); }
inline auto rbegin() const noexcept(NO_EXCEPT) { return std::make_reverse_iterator(this->end()); }
inline auto rend() const noexcept(NO_EXCEPT) { return std::make_reverse_iterator(this->begin()); }
struct iterator : iterator_interface {
protected:
value_type _n = 0;
size_type _index = 0;
const std::valarray<large_bit_type>* _flags = nullptr;
size_type _block = -1, _flag_size;
int _bit = 0;
inline value_type _value() const noexcept(NO_EXCEPT) {
if(this->_bit < 0) return numeric_limits<value_type>::arithmetic_infinity();
if(this->_block < 0) {<--- Unsigned less than zero
if(this->_bit == 0) return 2;
if(this->_bit == 1) return 3;
if(this->_bit == 2) return 5;
}
return (
value_type{30} * ((this->_block << 3) + (this->_bit >> 3)) +
prime_enumerator::MOD30[this->_bit & 7]
);
}
public:
iterator() noexcept = default;
iterator(const prime_enumerator *const super, const int bit) noexcept(NO_EXCEPT)
: _n(super->_n), _flags(&super->_large), _flag_size(static_cast<size_type>(super->_large.size())), _bit(bit) {
if(bit < 0) {
this->_index = super->size();
this->_block = static_cast<size_type>(super->_large.size()) - 1;
}
}
inline size_type index() const noexcept(NO_EXCEPT) { return this->_index; }
inline value_type operator*() const noexcept(NO_EXCEPT) {
const value_type res = this->_value();
return (res > this->_n ? -1 : res);
}
inline iterator& operator++() noexcept(NO_EXCEPT) {
if(this->_value() > this->_n) return *this;
++this->_index;
if(this->_block < 0) {<--- Unsigned less than zero
++this->_bit;
if(this->_bit > 2) this->_block = 0, this->_bit = 1;
return *this;
}
int next;
while(true) {
const large_bit_type mask = this->_bit >= 63 ? 0UL : ~((1UL << (this->_bit + 1)) - 1);
next = lowest_bit_pos(this->_flags->operator[](this->_block) & mask);
if(next >= 0) break;
this->_block++;<--- Prefer prefix ++/-- operators for non-primitive types. [+]Prefix ++/-- operators should be preferred for non-primitive types. Pre-increment/decrement can be more efficient than post-increment/decrement. Post-increment/decrement usually involves keeping a copy of the previous value around and adds a little extra code.
this->_bit = -1;
if(this->_block >= this->_flag_size) break;
}
this->_bit = next;
return *this;
}
inline iterator& operator--() noexcept(NO_EXCEPT) {
if(this->_block < 0) {<--- Unsigned less than zero
if(this->_bit > 0) --this->_bit, --this->_index;
return *this;
}
--this->_index;
int prev = -1;
while(true) {
if(0 < this->_bit) {
const large_bit_type mask = this->_bit >= 64 ? ~0UL : ((1UL << this->_bit) - 1);
prev = highest_bit_pos(this->_flags->operator[](this->_block) & mask);
}
if(prev >= 0) break;
--this->_block;
this->_bit = 64;
if(this->_block < 0) {<--- Unsigned less than zero
this->_bit = (this->_n >= 3) + (this->_n >= 5);
return *this;
}
}
this->_bit = prev;
return *this;
}
inline iterator operator++(int) noexcept(NO_EXCEPT) { const auto res = *this; ++(*this); return res; }
inline iterator operator--(int) noexcept(NO_EXCEPT) { const auto res = *this; --(*this); return res; }
friend inline bool operator==(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT) { return lhs._index == rhs._index; }
friend inline auto operator<=>(const iterator& lhs, const iterator& rhs) noexcept(NO_EXCEPT) { return lhs._index <=> rhs._index; }
friend inline auto operator-(const iterator& lhs, const iterator& rhs) { return lhs._index - rhs._index; }
};
};
} // namespace uni
namespace std::ranges {
template<class T>
inline constexpr bool enable_borrowed_range<uni::prime_enumerator<T>> = true;
} // namespace std::ranges
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