Function write_collection_data_fast

cpp/fory/serialization/collection_serializer.h:120–207

/// write collection data for non-polymorphic, non-shared-ref elements.
template <typename T, typename Container>
inline void write_collection_data_fast(const Container &coll, WriteContext &ctx,
                                       bool has_generics) {
  static_assert(!is_polymorphic_v<T>,
                "Fast path is for non-polymorphic types only");
  static_assert(!is_shared_ref_v<T>,
                "Fast path is for non-shared-ref types only");

  // write length
  ctx.write_var_uint32(static_cast<uint32_t>(coll.size()));

  if (coll.empty()) {
    return;
  }

  // Check for null elements
  bool has_null = false;
  if constexpr (is_nullable_v<T>) {
    for (const auto &elem : coll) {
      if (is_null_value(elem)) {
        has_null = true;
        break;
      }
    }
  }

  // Build header bitmap
  uint8_t bitmap = COLL_IS_SAME_TYPE;
  if (has_null) {
    bitmap |= COLL_HAS_NULL;
  }

  // Determine if element type is declared
  using ElemType = nullable_element_t<T>;
  bool is_elem_declared =
      has_generics && !need_type_for_collection_elem<ElemType>();
  if (is_elem_declared) {
    bitmap |= COLL_DECL_ELEMENT_TYPE;
  }

  // write header
  ctx.write_uint8(bitmap);

  // write element type info if not declared
  if (!is_elem_declared) {
    Serializer<ElemType>::write_type_info(ctx);
  }

  // write elements
  if constexpr (is_nullable_v<T>) {
    using Inner = nullable_element_t<T>;
    if (has_null) {
      for (const auto &elem : coll) {
        if (is_null_value(elem)) {
          ctx.write_int8(NULL_FLAG);
        } else {
          ctx.write_int8(NOT_NULL_VALUE_FLAG);
          if (is_elem_declared) {
            Serializer<Inner>::write_data(deref_nullable(elem), ctx);