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#ifndef MYGRATE_DBTYPES_H
#define MYGRATE_DBTYPES_H
#include "bitset.h"
#include <boost/numeric/conversion/cast.hpp>
#include <cstdint>
#include <span>
#include <string_view>
#include <variant>
struct timespec;
namespace MyGrate {
struct Date {
inline Date() { }
inline Date(uint16_t y, uint8_t m, uint8_t d) : year {y}, month {m}, day {d} { }
explicit inline Date(const tm & tm) : Date(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday) { }
uint16_t year;
uint8_t month;
uint8_t day;
};
struct Time {
inline Time() { }
inline Time(uint8_t h, uint8_t m, uint8_t s) : hour {h}, minute {m}, second {s} { }
explicit inline Time(const tm & tm) : Time(tm.tm_hour, tm.tm_min, tm.tm_sec) { }
uint8_t hour;
uint8_t minute;
uint8_t second;
};
struct DateTime : public Date, public Time {
inline DateTime() { }
inline DateTime(const Date & d, const Time & t) : Date {d}, Time {t} { }
explicit inline DateTime(const tm & tm) : Date {tm}, Time {tm} { }
};
using Blob = std::span<const std::byte>;
using DbValueV = std::variant<std::nullptr_t, double, float, int8_t, uint8_t, int16_t, uint16_t, int32_t, uint32_t,
int64_t, uint64_t, timespec, Date, Time, DateTime, std::string_view, BitSet, Blob>;
namespace detail {
template<typename I>
concept HasToString = requires
{
std::to_string(I {});
};
template<typename T> struct is_false {
static constexpr bool value {false};
};
template<typename R, template<typename> typename ConceptT> struct SafeExtract {
R
operator()(const R & i) const
{
return i;
}
template<typename I>
R
operator()(const I & i) const
{
if constexpr (ConceptT<I>::value) {
return boost::numeric_cast<R>(i);
}
else {
throw std::logic_error("Unreasonable conversion requested");
}
}
};
struct ToString {
std::string
operator()(const std::string_view & i) const
{
return std::string {i};
}
template<HasToString I>
std::string
operator()(const I & i) const
{
return std::to_string(i);
}
template<typename I>
std::string
operator()(const I &) const
{
throw std::logic_error("Unreasonable to_string requested");
}
};
}
class DbValue : public DbValueV {
public:
using DbValueV::DbValueV;
using DbValueV::operator=;
template<typename V>
inline auto
visit(V && v) const
{
return std::visit(std::forward<V>(v), static_cast<const DbValueV &>(*this));
}
template<typename T>
inline const auto &
get() const
{
return std::get<T>(static_cast<const DbValueV &>(*this));
}
template<typename R> operator R() const
{
if constexpr (std::is_integral_v<R>) {
return visit(detail::SafeExtract<R, std::is_integral> {});
}
else if constexpr (std::is_floating_point_v<R>) {
return visit(detail::SafeExtract<R, std::is_floating_point> {});
}
else if constexpr (std::is_same_v<std::string_view, R>) {
return get<std::string_view>();
}
else if constexpr (std::is_same_v<std::string, R>) {
return visit(detail::ToString {});
}
else {
static_assert(detail::is_false<R>::value, "Cannot extract one of these");
}
}
};
}
#endif
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