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#pragma once
#include "compat/assert.hpp"
#include <type_traits>
#include <utility>
#include <concepts>
namespace floormat::detail_Pack_output {
template<size_t N>
struct output_bits final
{
static_assert(N > 0);
static_assert(N < sizeof(size_t)*8);
static constexpr size_t length = N;
};
template<std::unsigned_integral T, size_t CAPACITY>
struct output
{
static_assert(std::is_fundamental_v<T>);
static_assert(CAPACITY <= sizeof(T)*8);
static constexpr size_t Capacity = CAPACITY;
T value{0};
template<size_t N>
constexpr T set(T x, output_bits<N>) const
{
static_assert(N <= CAPACITY, "data type too small");
static_assert(N > 0);
T value_{value};
if constexpr(CAPACITY != sizeof(T)*8)
value_ <<= CAPACITY;
auto x_ = T(x & (T{1}<<N)-T{1});
fm_assert(x_ == x);
value_ |= x_;
return value_;
}
template<size_t N>
struct next_
{
static_assert(N > 0);
static_assert(N <= CAPACITY);
using type = output<T, CAPACITY - N>;
};
template<size_t N> using next = typename next_<N>::type;
};
template<typename T, size_t N>
using output_field = std::pair<T, output_bits<N>>;
template<typename... Ts> struct empty_pack_tuple {}; // todo copypasta
template<typename T, size_t Left, size_t F, typename... Fields>
constexpr T write_(output<T, Left> st, output_field<T, F> field, Fields... fields)
{
T value = st.set(field.first, field.second);
using next = typename output<T, Left>::template next<F>;
return write_(next{value}, fields...);
}
template<typename T, size_t Left>
constexpr T write_(output<T, Left> st)
{
return st.value;
}
} // namespace floormat::detail_Pack_output
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