ser_common.h

#pragma once
#include "gaia/config/config.h"
 
#include <cstdint>
#include <type_traits>
 
#include "gaia/core/utility.h"
 
namespace gaia {
  namespace ser {
    enum class serialization_type_id : uint8_t {
      // Dummy
      ignore = 0,
 
      // Integer types
      s8 = 1,
      u8 = 2,
      s16 = 3,
      u16 = 4,
      s32 = 5,
      u32 = 6,
      s64 = 7,
      u64 = 8,
 
      // Boolean
      b = 9,
 
      // Character types
      c8 = 10,
      c16 = 11,
      c32 = 12,
      cw = 13,
 
      // Floating point types
      f8 = 14,
      f16 = 15,
      f32 = 16,
      f64 = 17,
      f128 = 18,
 
      // Special
      special_begin = 19,
      trivial_wrapper = special_begin,
      data_and_size = 20,
 
      Last = data_and_size,
    };
 
    inline uint32_t serialization_type_size(serialization_type_id id, uint32_t size) {
      static const uint32_t sizes[] = {
          // Dummy
          0, // ignore
 
          // Integer types
          1, // s8
          1, // u8
          2, // s16
          2, // u16
          4, // s32
          4, // u32
          8, // s64
          8, // u64
 
          // Boolean
          1, // b
 
          // Character types
          1, // c8
          2, // c16
          4, // c32
          8, // cw
 
          // Floating point types
          1, // f8
          2, // f16
          4, // f32
          8, // f64
          16, // f128
 
          // Special
          size, // trivial_wrapper
          sizeof(uintptr_t), // data_and_size, assume natural alignment
      };
 
      const auto s = sizes[(uint32_t)id];
      // Make sure we do not return an invalid value
      GAIA_ASSERT(s != (uint32_t)-1);
      return s;
    }
 
    template <typename T>
    struct is_trivially_serializable {
    private:
      static constexpr bool update() {
        return std::is_enum_v<T> || std::is_fundamental_v<T> || std::is_trivially_copyable_v<T>;
      }
 
    public:
      static constexpr bool value = update();
    };
 
    template <typename T>
    struct is_int_kind_id:
        std::disjunction<
            std::is_same<T, char>, std::is_same<T, unsigned char>, //
            std::is_same<T, int8_t>, std::is_same<T, uint8_t>, //
            std::is_same<T, int16_t>, std::is_same<T, uint16_t>, //
            std::is_same<T, int32_t>, std::is_same<T, uint32_t>, //
            std::is_same<T, int64_t>, std::is_same<T, uint64_t>, //
            std::is_same<T, size_t>, std::is_same<T, bool>> {};
 
    template <typename T>
    struct is_flt_kind_id:
        std::disjunction<
            // std::is_same<T, float8_t>, //
            // std::is_same<T, float16_t>, //
            std::is_same<T, float>, //
            std::is_same<T, double>, //
            std::is_same<T, long double>> {};
 
    template <typename T>
    GAIA_NODISCARD constexpr serialization_type_id int_kind_id() {
      static_assert(is_int_kind_id<T>::value, "Unsupported integral type");
 
      if constexpr (std::is_same_v<char, T>) {
        return serialization_type_id::s8;
      } else if constexpr (std::is_same_v<unsigned char, T>) {
        return serialization_type_id::u8;
      } else if constexpr (std::is_same_v<int8_t, T>) {
        return serialization_type_id::s8;
      } else if constexpr (std::is_same_v<uint8_t, T>) {
        return serialization_type_id::u8;
      } else if constexpr (std::is_same_v<int16_t, T>) {
        return serialization_type_id::s16;
      } else if constexpr (std::is_same_v<uint16_t, T>) {
        return serialization_type_id::u16;
      } else if constexpr (std::is_same_v<int32_t, T>) {
        return serialization_type_id::s32;
      } else if constexpr (std::is_same_v<uint32_t, T>) {
        return serialization_type_id::u32;
      } else if constexpr (std::is_same_v<int64_t, T>) {
        return serialization_type_id::s64;
      } else if constexpr (std::is_same_v<uint64_t, T>) {
        return serialization_type_id::u64;
      } else if constexpr (std::is_same_v<size_t, T>) {
        return serialization_type_id::u64;
      } else { // if constexpr (std::is_same_v<bool, T>) {
        return serialization_type_id::b;
      }
    }
 
    template <typename T>
    GAIA_NODISCARD constexpr serialization_type_id flt_type_id() {
      static_assert(is_flt_kind_id<T>::value, "Unsupported floating type");
 
      // if constexpr (std::is_same_v<float8_t, T>) {
      //  return serialization_type_id::f8;
      // } else if constexpr (std::is_same_v<float16_t, T>) {
      //  return serialization_type_id::f16;
      // } else
      if constexpr (std::is_same_v<float, T>) {
        return serialization_type_id::f32;
      } else if constexpr (std::is_same_v<double, T>) {
        return serialization_type_id::f64;
      } else { // if constexpr (std::is_same_v<long double, T>) {
        return serialization_type_id::f128;
      }
    }
 
    template <typename T>
    GAIA_NODISCARD constexpr serialization_type_id type_id() {
      if constexpr (std::is_enum_v<T>)
        return int_kind_id<std::underlying_type_t<T>>();
      else if constexpr (std::is_integral_v<T>)
        return int_kind_id<T>();
      else if constexpr (std::is_floating_point_v<T>)
        return flt_type_id<T>();
      else if constexpr (std::is_pointer_v<T>)
        return serialization_type_id::data_and_size;
      else if constexpr (core::has_size_begin_end<T>::value)
        return serialization_type_id::data_and_size;
      else if constexpr (std::is_class_v<T>)
        return serialization_type_id::trivial_wrapper;
      else
        return serialization_type_id::ignore;
    }
 
    // --------------------
    // Define function detectors
    // --------------------
 
    GAIA_DEFINE_HAS_MEMBER_FUNC(save);
    GAIA_DEFINE_HAS_MEMBER_FUNC(load);
    GAIA_DEFINE_HAS_MEMBER_FUNC(resize);
 
    // --------------------
    // Customization tags
    // --------------------
 
    struct save_tag {};
    struct load_tag {};
    inline constexpr save_tag save_v{};
    inline constexpr load_tag load_v{};
 
    // --------------------
    // Detection traits
    // --------------------
 
    template <typename S, typename T>
    auto has_tag_save_impl(int)
        -> decltype(tag_invoke(save_v, std::declval<S&>(), std::declval<const T&>()), std::true_type{});
    template <typename, typename>
    std::false_type has_tag_save_impl(...);
    template <typename S, typename T>
    using has_tag_save = decltype(has_tag_save_impl<S, T>(0));
 
    template <typename S, typename T>
    auto has_tag_load_impl(int)
        -> decltype(tag_invoke(load_v, std::declval<S&>(), std::declval<T&>()), std::true_type{});
    template <typename, typename>
    std::false_type has_tag_load_impl(...);
    template <typename S, typename T>
    using has_tag_load = decltype(has_tag_load_impl<S, T>(0));
  } // namespace ser
} // namespace gaia