text: /*
   * Copyright 2014 Google Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  // independent from idl_parser, since this code is not needed for most clients
  
  #include "flatbuffers/code_generators.h"
  #include "flatbuffers/flatbuffers.h"
  #include "flatbuffers/idl.h"
  #include "flatbuffers/util.h"
  
  #include <unordered_set>
  
  namespace flatbuffers {
  
  // Pedantic warning free version of toupper().
  inline char ToUpper(char c) { return static_cast<char>(::toupper(c)); }
  
  // Make numerical literal with type-suffix.
  // This function is only needed for C++! Other languages do not need it.
  static inline std::string NumToStringCpp(std::string val, BaseType type) {
    // Avoid issues with -2147483648, -9223372036854775808.
    switch (type) {
      case BASE_TYPE_INT:
        return (val != "-2147483648") ? val : ("(-2147483647 - 1)");
      case BASE_TYPE_ULONG: return (val == "0") ? val : (val + "ULL");
      case BASE_TYPE_LONG:
        if (val == "-9223372036854775808")
          return "(-9223372036854775807LL - 1LL)";
        else
          return (val == "0") ? val : (val + "LL");
      default: return val;
    }
  }
  
  static std::string GeneratedFileName(const std::string &path,
                                       const std::string &file_name) {
    return path + file_name + "_generated.h";
  }
  
  namespace cpp {
  class CppGenerator : public BaseGenerator {
   public:
    CppGenerator(const Parser &parser, const std::string &path,
                 const std::string &file_name)
        : BaseGenerator(parser, path, file_name, "", "::"),
          cur_name_space_(nullptr),
          float_const_gen_("std::numeric_limits<double>::",
                           "std::numeric_limits<float>::", "quiet_NaN()",
                           "infinity()") {
      static const char *const keywords[] = {
        "alignas",
        "alignof",
        "and",
        "and_eq",
        "asm",
        "atomic_cancel",
        "atomic_commit",
        "atomic_noexcept",
        "auto",
        "bitand",
        "bitor",
        "bool",
        "break",
        "case",
        "catch",
        "char",
        "char16_t",
        "char32_t",
        "class",
        "compl",
        "concept",
        "const",
        "constexpr",
        "const_cast",
        "continue",
        "co_await",
        "co_return",
        "co_yield",
        "decltype",
        "default",
        "delete",
        "do",
        "double",
        "dynamic_cast",
        "else",
        "enum",
        "explicit",
        "export",
        "extern",
        "false",
        "float",
        "for",
        "friend",
        "goto",
        "if",
        "import",
        "inline",
        "int",
        "long",
        "module",
        "mutable",
        "namespace",
        "new",
        "noexcept",
        "not",
        "not_eq",
        "nullptr",
        "operator",
        "or",
        "or_eq",
        "private",
        "protected",
        "public",
        "register",
        "reinterpret_cast",
        "requires",
        "return",
        "short",
        "signed",
        "sizeof",
        "static",
        "static_assert",
        "static_cast",
        "struct",
        "switch",
        "synchronized",
        "template",
        "this",
        "thread_local",
        "throw",
        "true",
        "try",
        "typedef",
        "typeid",
        "typename",
        "union",
        "unsigned",
        "using",
        "virtual",
        "void",
        "volatile",
        "wchar_t",
        "while",
        "xor",
        "xor_eq",
        nullptr,
      };
      for (auto kw = keywords; *kw; kw++) keywords_.insert(*kw);
    }
  
    std::string GenIncludeGuard() const {
      // Generate include guard.
      std::string guard = file_name_;
      // Remove any non-alpha-numeric characters that may appear in a filename.
      struct IsAlnum {
        bool operator()(char c) const { return !is_alnum(c); }
      };
      guard.erase(std::remove_if(guard.begin(), guard.end(), IsAlnum()),
                  guard.end());
      guard = "FLATBUFFERS_GENERATED_" + guard;
      guard += "_";
      // For further uniqueness, also add the namespace.
      auto name_space = parser_.current_namespace_;
      for (auto it = name_space->components.begin();
           it != name_space->components.end(); ++it) {
        guard += *it + "_";
      }
      guard += "H_";
      std::transform(guard.begin(), guard.end(), guard.begin(), ToUpper);
      return guard;
    }
  
    void GenIncludeDependencies() {
      int num_includes = 0;
      for (auto it = parser_.native_included_files_.begin();
           it != parser_.native_included_files_.end(); ++it) {
        code_ += "#include \"" + *it + "\"";
        num_includes++;
      }
      for (auto it = parser_.included_files_.begin();
           it != parser_.included_files_.end(); ++it) {
        if (it->second.empty()) continue;
        auto noext = flatbuffers::StripExtension(it->second);
        auto basename = flatbuffers::StripPath(noext);
  
        code_ += "#include \"" + parser_.opts.include_prefix +
                 (parser_.opts.keep_include_path ? noext : basename) +
                 "_generated.h\"";
        num_includes++;
      }
      if (num_includes) code_ += "";
    }
  
    std::string EscapeKeyword(const std::string &name) const {
      return keywords_.find(name) == keywords_.end() ? name : name + "_";
    }
  
    std::string Name(const Definition &def) const {
      return EscapeKeyword(def.name);
    }
  
    std::string Name(const EnumVal &ev) const { return EscapeKeyword(ev.name); }
  
    // Iterate through all definitions we haven't generate code for (enums,
    // structs, and tables) and output them to a single file.
    bool generate() {
      code_.Clear();
      code_ += "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n";
  
      const auto include_guard = GenIncludeGuard();
      code_ += "#ifndef " + include_guard;
      code_ += "#define " + include_guard;
      code_ += "";
  
      if (parser_.opts.gen_nullable) {
        code_ += "#pragma clang system_header\n\n";
      }
  
      code_ += "#include \"flatbuffers/flatbuffers.h\"";
      if (parser_.uses_flexbuffers_) {
        code_ += "#include \"flatbuffers/flexbuffers.h\"";
      }
      code_ += "";
  
      if (parser_.opts.include_dependence_headers) { GenIncludeDependencies(); }
  
      FLATBUFFERS_ASSERT(!cur_name_space_);
  
      // Generate forward declarations for all structs/tables, since they may
      // have circular references.
      for (auto it = parser_.structs_.vec.begin();
           it != parser_.structs_.vec.end(); ++it) {
        const auto &struct_def = **it;
        if (!struct_def.generated) {
          SetNameSpace(struct_def.defined_namespace);
          code_ += "struct " + Name(struct_def) + ";";
          if (parser_.opts.generate_object_based_api) {
            auto nativeName =
                NativeName(Name(struct_def), &struct_def, parser_.opts);
            if (!struct_def.fixed) { code_ += "struct " + nativeName + ";"; }
          }
          code_ += "";
        }
      }
  
      // Generate forward declarations for all equal operators
      if (parser_.opts.generate_object_based_api && parser_.opts.gen_compare) {
        for (auto it = parser_.structs_.vec.begin();
             it != parser_.structs_.vec.end(); ++it) {
          const auto &struct_def = **it;
          if (!struct_def.generated) {
            SetNameSpace(struct_def.defined_namespace);
            auto nativeName =
                NativeName(Name(struct_def), &struct_def, parser_.opts);
            code_ += "bool operator==(const " + nativeName + " &lhs, const " +
                     nativeName + " &rhs);";
            code_ += "bool operator!=(const " + nativeName + " &lhs, const " +
                nativeName + " &rhs);";
          }
        }
        code_ += "";
      }
  
      // Generate preablmle code for mini reflection.
      if (parser_.opts.mini_reflect != IDLOptions::kNone) {
        // To break cyclic dependencies, first pre-declare all tables/structs.
        for (auto it = parser_.structs_.vec.begin();
             it != parser_.structs_.vec.end(); ++it) {
          const auto &struct_def = **it;
          if (!struct_def.generated) {
            SetNameSpace(struct_def.defined_namespace);
            GenMiniReflectPre(&struct_def);
          }
        }
      }
  
      // Generate code for all the enum declarations.
      for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
           ++it) {
        const auto &enum_def = **it;
        if (!enum_def.generated) {
          SetNameSpace(enum_def.defined_namespace);
          GenEnum(enum_def);
        }
      }
  
      // Generate code for all structs, then all tables.
      for (auto it = parser_.structs_.vec.begin();
           it != parser_.structs_.vec.end(); ++it) {
        const auto &struct_def = **it;
        if (struct_def.fixed && !struct_def.generated) {
          SetNameSpace(struct_def.defined_namespace);
          GenStruct(struct_def);
        }
      }
      for (auto it = parser_.structs_.vec.begin();
           it != parser_.structs_.vec.end(); ++it) {
        const auto &struct_def = **it;
        if (!struct_def.fixed && !struct_def.generated) {
          SetNameSpace(struct_def.defined_namespace);
          GenTable(struct_def);
        }
      }
      for (auto it = parser_.structs_.vec.begin();
           it != parser_.structs_.vec.end(); ++it) {
        const auto &struct_def = **it;
        if (!struct_def.fixed && !struct_def.generated) {
          SetNameSpace(struct_def.defined_namespace);
          GenTablePost(struct_def);
        }
      }
  
      // Generate code for union verifiers.
      for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
           ++it) {
        const auto &enum_def = **it;
        if (enum_def.is_union && !enum_def.generated) {
          SetNameSpace(enum_def.defined_namespace);
          GenUnionPost(enum_def);
        }
      }
  
      // Generate code for mini reflection.
      if (parser_.opts.mini_reflect != IDLOptions::kNone) {
        // Then the unions/enums that may refer to them.
        for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
             ++it) {
          const auto &enum_def = **it;
          if (!enum_def.generated) {
            SetNameSpace(enum_def.defined_namespace);
            GenMiniReflect(nullptr, &enum_def);
          }
        }
        // Then the full tables/structs.
        for (auto it = parser_.structs_.vec.begin();
             it != parser_.structs_.vec.end(); ++it) {
          const auto &struct_def = **it;
          if (!struct_def.generated) {
            SetNameSpace(struct_def.defined_namespace);
            GenMiniReflect(&struct_def, nullptr);
          }
        }
      }
  
      // Generate convenient global helper functions:
      if (parser_.root_struct_def_) {
        auto &struct_def = *parser_.root_struct_def_;
        SetNameSpace(struct_def.defined_namespace);
        auto name = Name(struct_def);
        auto qualified_name = cur_name_space_->GetFullyQualifiedName(name);
        auto cpp_name = TranslateNameSpace(qualified_name);
  
        code_.SetValue("STRUCT_NAME", name);
        code_.SetValue("CPP_NAME", cpp_name);
        code_.SetValue("NULLABLE_EXT", NullableExtension());
  
        // The root datatype accessor:
        code_ += "inline \\";
        code_ +=
            "const {{CPP_NAME}} *{{NULLABLE_EXT}}Get{{STRUCT_NAME}}(const void "
            "*buf) {";
        code_ += "  return flatbuffers::GetRoot<{{CPP_NAME}}>(buf);";
        code_ += "}";
        code_ += "";
  
        code_ += "inline \\";
        code_ +=
            "const {{CPP_NAME}} "
            "*{{NULLABLE_EXT}}GetSizePrefixed{{STRUCT_NAME}}(const void "
            "*buf) {";
        code_ += "  return flatbuffers::GetSizePrefixedRoot<{{CPP_NAME}}>(buf);";
        code_ += "}";
        code_ += "";
  
        if (parser_.opts.mutable_buffer) {
          code_ += "inline \\";
          code_ += "{{STRUCT_NAME}} *GetMutable{{STRUCT_NAME}}(void *buf) {";
          code_ += "  return flatbuffers::GetMutableRoot<{{STRUCT_NAME}}>(buf);";
          code_ += "}";
          code_ += "";
        }
  
        if (parser_.file_identifier_.length()) {
          // Return the identifier
          code_ += "inline const char *{{STRUCT_NAME}}Identifier() {";
          code_ += "  return \"" + parser_.file_identifier_ + "\";";
          code_ += "}";
          code_ += "";
  
          // Check if a buffer has the identifier.
          code_ += "inline \\";
          code_ += "bool {{STRUCT_NAME}}BufferHasIdentifier(const void *buf) {";
          code_ += "  return flatbuffers::BufferHasIdentifier(";
          code_ += "      buf, {{STRUCT_NAME}}Identifier());";
          code_ += "}";
          code_ += "";
        }
  
        // The root verifier.
        if (parser_.file_identifier_.length()) {
          code_.SetValue("ID", name + "Identifier()");
        } else {
          code_.SetValue("ID", "nullptr");
        }
  
        code_ += "inline bool Verify{{STRUCT_NAME}}Buffer(";
        code_ += "    flatbuffers::Verifier &verifier) {";
        code_ += "  return verifier.VerifyBuffer<{{CPP_NAME}}>({{ID}});";
        code_ += "}";
        code_ += "";
  
        code_ += "inline bool VerifySizePrefixed{{STRUCT_NAME}}Buffer(";
        code_ += "    flatbuffers::Verifier &verifier) {";
        code_ +=
            "  return verifier.VerifySizePrefixedBuffer<{{CPP_NAME}}>({{ID}});";
        code_ += "}";
        code_ += "";
  
        if (parser_.file_extension_.length()) {
          // Return the extension
          code_ += "inline const char *{{STRUCT_NAME}}Extension() {";
          code_ += "  return \"" + parser_.file_extension_ + "\";";
          code_ += "}";
          code_ += "";
        }
  
        // Finish a buffer with a given root object:
        code_ += "inline void Finish{{STRUCT_NAME}}Buffer(";
        code_ += "    flatbuffers::FlatBufferBuilder &fbb,";
        code_ += "    flatbuffers::Offset<{{CPP_NAME}}> root) {";
        if (parser_.file_identifier_.length())
          code_ += "  fbb.Finish(root, {{STRUCT_NAME}}Identifier());";
        else
          code_ += "  fbb.Finish(root);";
        code_ += "}";
        code_ += "";
  
        code_ += "inline void FinishSizePrefixed{{STRUCT_NAME}}Buffer(";
        code_ += "    flatbuffers::FlatBufferBuilder &fbb,";
        code_ += "    flatbuffers::Offset<{{CPP_NAME}}> root) {";
        if (parser_.file_identifier_.length())
          code_ += "  fbb.FinishSizePrefixed(root, {{STRUCT_NAME}}Identifier());";
        else
          code_ += "  fbb.FinishSizePrefixed(root);";
        code_ += "}";
        code_ += "";
  
        if (parser_.opts.generate_object_based_api) {
          // A convenient root unpack function.
          auto native_name =
              NativeName(WrapInNameSpace(struct_def), &struct_def, parser_.opts);
          code_.SetValue("UNPACK_RETURN",
                         GenTypeNativePtr(native_name, nullptr, false));
          code_.SetValue("UNPACK_TYPE",
                         GenTypeNativePtr(native_name, nullptr, true));
  
          code_ += "inline {{UNPACK_RETURN}} UnPack{{STRUCT_NAME}}(";
          code_ += "    const void *buf,";
          code_ += "    const flatbuffers::resolver_function_t *res = nullptr) {";
          code_ += "  return {{UNPACK_TYPE}}\\";
          code_ += "(Get{{STRUCT_NAME}}(buf)->UnPack(res));";
          code_ += "}";
          code_ += "";
        }
      }
  
      if (cur_name_space_) SetNameSpace(nullptr);
  
      // Close the include guard.
      code_ += "#endif  // " + include_guard;
  
      const auto file_path = GeneratedFileName(path_, file_name_);
      const auto final_code = code_.ToString();
      return SaveFile(file_path.c_str(), final_code, false);
    }
  
   private:
    CodeWriter code_;
  
    std::unordered_set<std::string> keywords_;
  
    // This tracks the current namespace so we can insert namespace declarations.
    const Namespace *cur_name_space_;
  
    const Namespace *CurrentNameSpace() const { return cur_name_space_; }
  
    // Translates a qualified name in flatbuffer text format to the same name in
    // the equivalent C++ namespace.
    static std::string TranslateNameSpace(const std::string &qualified_name) {
      std::string cpp_qualified_name = qualified_name;
      size_t start_pos = 0;
      while ((start_pos = cpp_qualified_name.find(".", start_pos)) !=
             std::string::npos) {
        cpp_qualified_name.replace(start_pos, 1, "::");
      }
      return cpp_qualified_name;
    }
  
    void GenComment(const std::vector<std::string> &dc, const char *prefix = "") {
      std::string text;
      ::flatbuffers::GenComment(dc, &text, nullptr, prefix);
      code_ += text + "\\";
    }
  
    // Return a C++ type from the table in idl.h
    std::string GenTypeBasic(const Type &type, bool user_facing_type) const {
      // clang-format off
      static const char *const ctypename[] = {
      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
                             RTYPE) \
              #CTYPE,
          FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
      #undef FLATBUFFERS_TD
      };
      // clang-format on
      if (user_facing_type) {
        if (type.enum_def) return WrapInNameSpace(*type.enum_def);
        if (type.base_type == BASE_TYPE_BOOL) return "bool";
      }
      return ctypename[type.base_type];
    }
  
    // Return a C++ pointer type, specialized to the actual struct/table types,
    // and vector element types.
    std::string GenTypePointer(const Type &type) const {
      switch (type.base_type) {
        case BASE_TYPE_STRING: {
          return "flatbuffers::String";
        }
        case BASE_TYPE_VECTOR: {
          const auto type_name = GenTypeWire(type.VectorType(), "", false);
          return "flatbuffers::Vector<" + type_name + ">";
        }
        case BASE_TYPE_STRUCT: {
          return WrapInNameSpace(*type.struct_def);
        }
        case BASE_TYPE_UNION:
        // fall through
        default: { return "void"; }
      }
    }
  
    // Return a C++ type for any type (scalar/pointer) specifically for
    // building a flatbuffer.
    std::string GenTypeWire(const Type &type, const char *postfix,
                            bool user_facing_type) const {
      if (IsScalar(type.base_type)) {
        return GenTypeBasic(type, user_facing_type) + postfix;
      } else if (IsStruct(type)) {
        return "const " + GenTypePointer(type) + " *";
      } else {
        return "flatbuffers::Offset<" + GenTypePointer(type) + ">" + postfix;
      }
    }
  
    // Return a C++ type for any type (scalar/pointer) that reflects its
    // serialized size.
    std::string GenTypeSize(const Type &type) const {
      if (IsScalar(type.base_type)) {
        return GenTypeBasic(type, false);
      } else if (IsStruct(type)) {
        return GenTypePointer(type);
      } else {
        return "flatbuffers::uoffset_t";
      }
    }
  
    std::string NullableExtension() {
      return parser_.opts.gen_nullable ? " _Nullable " : "";
    }
  
    static std::string NativeName(const std::string &name, const StructDef *sd,
                                  const IDLOptions &opts) {
      return sd && !sd->fixed ? opts.object_prefix + name + opts.object_suffix
                              : name;
    }
  
    const std::string &PtrType(const FieldDef *field) {
      auto attr = field ? field->attributes.Lookup("cpp_ptr_type") : nullptr;
      return attr ? attr->constant : parser_.opts.cpp_object_api_pointer_type;
    }
  
    const std::string NativeString(const FieldDef *field) {
      auto attr = field ? field->attributes.Lookup("cpp_str_type") : nullptr;
      auto &ret = attr ? attr->constant : parser_.opts.cpp_object_api_string_type;
      if (ret.empty()) { return "std::string"; }
      return ret;
    }
  
    bool FlexibleStringConstructor(const FieldDef *field) {
      auto attr = field
                      ? (field->attributes.Lookup("cpp_str_flex_ctor") != nullptr)
                      : false;
      auto ret =
          attr ? attr : parser_.opts.cpp_object_api_string_flexible_constructor;
      return ret && NativeString(field) !=
                        "std::string";  // Only for custom string types.
    }
  
    std::string GenTypeNativePtr(const std::string &type, const FieldDef *field,
                                 bool is_constructor) {
      auto &ptr_type = PtrType(field);
      if (ptr_type != "naked") {
        return (ptr_type != "default_ptr_type"
                    ? ptr_type
                    : parser_.opts.cpp_object_api_pointer_type) +
               "<" + type + ">";
      } else if (is_constructor) {
        return "";
      } else {
        return type + " *";
      }
    }
  
    std::string GenPtrGet(const FieldDef &field) {
      auto cpp_ptr_type_get = field.attributes.Lookup("cpp_ptr_type_get");
      if (cpp_ptr_type_get) return cpp_ptr_type_get->constant;
      auto &ptr_type = PtrType(&field);
      return ptr_type == "naked" ? "" : ".get()";
    }
  
    std::string GenTypeNative(const Type &type, bool invector,
                              const FieldDef &field) {
      switch (type.base_type) {
        case BASE_TYPE_STRING: {
          return NativeString(&field);
        }
        case BASE_TYPE_VECTOR: {
          const auto type_name = GenTypeNative(type.VectorType(), true, field);
          if (type.struct_def &&
              type.struct_def->attributes.Lookup("native_custom_alloc")) {
            auto native_custom_alloc =
                type.struct_def->attributes.Lookup("native_custom_alloc");
            return "std::vector<" + type_name + "," +
                   native_custom_alloc->constant + "<" + type_name + ">>";
          } else
            return "std::vector<" + type_name + ">";
        }
        case BASE_TYPE_STRUCT: {
          auto type_name = WrapInNameSpace(*type.struct_def);
          if (IsStruct(type)) {
            auto native_type = type.struct_def->attributes.Lookup("native_type");
            if (native_type) { type_name = native_type->constant; }
            if (invector || field.native_inline) {
              return type_name;
            } else {
              return GenTypeNativePtr(type_name, &field, false);
            }
          } else {
            return GenTypeNativePtr(
                NativeName(type_name, type.struct_def, parser_.opts), &field,
                false);
          }
        }
        case BASE_TYPE_UNION: {
          return type.enum_def->name + "Union";
        }
        default: { return GenTypeBasic(type, true); }
      }
    }
  
    // Return a C++ type for any type (scalar/pointer) specifically for
    // using a flatbuffer.
    std::string GenTypeGet(const Type &type, const char *afterbasic,
                           const char *beforeptr, const char *afterptr,
                           bool user_facing_type) {
      if (IsScalar(type.base_type)) {
        return GenTypeBasic(type, user_facing_type) + afterbasic;
      } else {
        return beforeptr + GenTypePointer(type) + afterptr;
      }
    }
  
    std::string GenEnumDecl(const EnumDef &enum_def) const {
      const IDLOptions &opts = parser_.opts;
      return (opts.scoped_enums ? "enum class " : "enum ") + Name(enum_def);
    }
  
    std::string GenEnumValDecl(const EnumDef &enum_def,
                               const std::string &enum_val) const {
      const IDLOptions &opts = parser_.opts;
      return opts.prefixed_enums ? Name(enum_def) + "_" + enum_val : enum_val;
    }
  
    std::string GetEnumValUse(const EnumDef &enum_def,
                              const EnumVal &enum_val) const {
      const IDLOptions &opts = parser_.opts;
      if (opts.scoped_enums) {
        return Name(enum_def) + "::" + Name(enum_val);
      } else if (opts.prefixed_enums) {
        return Name(enum_def) + "_" + Name(enum_val);
      } else {
        return Name(enum_val);
      }
    }
  
    std::string StripUnionType(const std::string &name) {
      return name.substr(0, name.size() - strlen(UnionTypeFieldSuffix()));
    }
  
    std::string GetUnionElement(const EnumVal &ev, bool wrap, bool actual_type,
                                bool native_type = false) {
      if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
        auto name = actual_type ? ev.union_type.struct_def->name : Name(ev);
        return wrap ? WrapInNameSpace(ev.union_type.struct_def->defined_namespace,
                                      name)
                    : name;
      } else if (ev.union_type.base_type == BASE_TYPE_STRING) {
        return actual_type ? (native_type ? "std::string" : "flatbuffers::String")
                           : Name(ev);
      } else {
        FLATBUFFERS_ASSERT(false);
        return Name(ev);
      }
    }
  
    std::string UnionVerifySignature(const EnumDef &enum_def) {
      return "bool Verify" + Name(enum_def) +
             "(flatbuffers::Verifier &verifier, const void *obj, " +
             Name(enum_def) + " type)";
    }
  
    std::string UnionVectorVerifySignature(const EnumDef &enum_def) {
      return "bool Verify" + Name(enum_def) + "Vector" +
             "(flatbuffers::Verifier &verifier, " +
             "const flatbuffers::Vector<flatbuffers::Offset<void>> *values, " +
             "const flatbuffers::Vector<uint8_t> *types)";
    }
  
    std::string UnionUnPackSignature(const EnumDef &enum_def, bool inclass) {
      return (inclass ? "static " : "") + std::string("void *") +
             (inclass ? "" : Name(enum_def) + "Union::") +
             "UnPack(const void *obj, " + Name(enum_def) +
             " type, const flatbuffers::resolver_function_t *resolver)";
    }
  
    std::string UnionPackSignature(const EnumDef &enum_def, bool inclass) {
      return "flatbuffers::Offset<void> " +
             (inclass ? "" : Name(enum_def) + "Union::") +
             "Pack(flatbuffers::FlatBufferBuilder &_fbb, " +
             "const flatbuffers::rehasher_function_t *_rehasher" +
             (inclass ? " = nullptr" : "") + ") const";
    }
  
    std::string TableCreateSignature(const StructDef &struct_def, bool predecl,
                                     const IDLOptions &opts) {
      return "flatbuffers::Offset<" + Name(struct_def) + "> Create" +
             Name(struct_def) + "(flatbuffers::FlatBufferBuilder &_fbb, const " +
             NativeName(Name(struct_def), &struct_def, opts) +
             " *_o, const flatbuffers::rehasher_function_t *_rehasher" +
             (predecl ? " = nullptr" : "") + ")";
    }
  
    std::string TablePackSignature(const StructDef &struct_def, bool inclass,
                                   const IDLOptions &opts) {
      return std::string(inclass ? "static " : "") + "flatbuffers::Offset<" +
             Name(struct_def) + "> " + (inclass ? "" : Name(struct_def) + "::") +
             "Pack(flatbuffers::FlatBufferBuilder &_fbb, " + "const " +
             NativeName(Name(struct_def), &struct_def, opts) + "* _o, " +
             "const flatbuffers::rehasher_function_t *_rehasher" +
             (inclass ? " = nullptr" : "") + ")";
    }
  
    std::string TableUnPackSignature(const StructDef &struct_def, bool inclass,
                                     const IDLOptions &opts) {
      return NativeName(Name(struct_def), &struct_def, opts) + " *" +
             (inclass ? "" : Name(struct_def) + "::") +
             "UnPack(const flatbuffers::resolver_function_t *_resolver" +
             (inclass ? " = nullptr" : "") + ") const";
    }
  
    std::string TableUnPackToSignature(const StructDef &struct_def, bool inclass,
                                       const IDLOptions &opts) {
      return "void " + (inclass ? "" : Name(struct_def) + "::") + "UnPackTo(" +
             NativeName(Name(struct_def), &struct_def, opts) + " *" +
             "_o, const flatbuffers::resolver_function_t *_resolver" +
             (inclass ? " = nullptr" : "") + ") const";
    }
  
    void GenMiniReflectPre(const StructDef *struct_def) {
      code_.SetValue("NAME", struct_def->name);
      code_ += "inline const flatbuffers::TypeTable *{{NAME}}TypeTable();";
      code_ += "";
    }
  
    void GenMiniReflect(const StructDef *struct_def, const EnumDef *enum_def) {
      code_.SetValue("NAME", struct_def ? struct_def->name : enum_def->name);
      code_.SetValue("SEQ_TYPE",
                     struct_def ? (struct_def->fixed ? "ST_STRUCT" : "ST_TABLE")
                                : (enum_def->is_union ? "ST_UNION" : "ST_ENUM"));
      auto num_fields =
          struct_def ? struct_def->fields.vec.size() : enum_def->size();
      code_.SetValue("NUM_FIELDS", NumToString(num_fields));
      std::vector<std::string> names;
      std::vector<Type> types;
  
      if (struct_def) {
        for (auto it = struct_def->fields.vec.begin();
             it != struct_def->fields.vec.end(); ++it) {
          const auto &field = **it;
          names.push_back(Name(field));
          types.push_back(field.value.type);
        }
      } else {
        for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
             ++it) {
          const auto &ev = **it;
          names.push_back(Name(ev));
          types.push_back(enum_def->is_union ? ev.union_type
                                             : Type(enum_def->underlying_type));
        }
      }
      std::string ts;
      std::vector<std::string> type_refs;
      for (auto it = types.begin(); it != types.end(); ++it) {
        auto &type = *it;
        if (!ts.empty()) ts += ",\n    ";
        auto is_vector = type.base_type == BASE_TYPE_VECTOR;
        auto bt = is_vector ? type.element : type.base_type;
        auto et = IsScalar(bt) || bt == BASE_TYPE_STRING
                      ? bt - BASE_TYPE_UTYPE + ET_UTYPE
                      : ET_SEQUENCE;
        int ref_idx = -1;
        std::string ref_name =
            type.struct_def
                ? WrapInNameSpace(*type.struct_def)
                : type.enum_def ? WrapInNameSpace(*type.enum_def) : "";
        if (!ref_name.empty()) {
          auto rit = type_refs.begin();
          for (; rit != type_refs.end(); ++rit) {
            if (*rit == ref_name) {
              ref_idx = static_cast<int>(rit - type_refs.begin());
              break;
            }
          }
          if (rit == type_refs.end()) {
            ref_idx = static_cast<int>(type_refs.size());
            type_refs.push_back(ref_name);
          }
        }
        ts += "{ flatbuffers::" + std::string(ElementaryTypeNames()[et]) + ", " +
              NumToString(is_vector) + ", " + NumToString(ref_idx) + " }";
      }
      std::string rs;
      for (auto it = type_refs.begin(); it != type_refs.end(); ++it) {
        if (!rs.empty()) rs += ",\n    ";
        rs += *it + "TypeTable";
      }
      std::string ns;
      for (auto it = names.begin(); it != names.end(); ++it) {
        if (!ns.empty()) ns += ",\n    ";
        ns += "\"" + *it + "\"";
      }
      std::string vs;
      const auto consecutive_enum_from_zero =
          enum_def && enum_def->MinValue()->IsZero() &&
          ((enum_def->size() - 1) == enum_def->Distance());
      if (enum_def && !consecutive_enum_from_zero) {
        for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
             ++it) {
          const auto &ev = **it;
          if (!vs.empty()) vs += ", ";
          vs += NumToStringCpp(enum_def->ToString(ev),
                               enum_def->underlying_type.base_type);
        }
      } else if (struct_def && struct_def->fixed) {
        for (auto it = struct_def->fields.vec.begin();
             it != struct_def->fields.vec.end(); ++it) {
          const auto &field = **it;
          vs += NumToString(field.value.offset);
          vs += ", ";
        }
        vs += NumToString(struct_def->bytesize);
      }
      code_.SetValue("TYPES", ts);
      code_.SetValue("REFS", rs);
      code_.SetValue("NAMES", ns);
      code_.SetValue("VALUES", vs);
      code_ += "inline const flatbuffers::TypeTable *{{NAME}}TypeTable() {";
      if (num_fields) {
        code_ += "  static const flatbuffers::TypeCode type_codes[] = {";
        code_ += "    {{TYPES}}";
        code_ += "  };";
      }
      if (!type_refs.empty()) {
        code_ += "  static const flatbuffers::TypeFunction type_refs[] = {";
        code_ += "    {{REFS}}";
        code_ += "  };";
      }
      if (!vs.empty()) {
        // Problem with uint64_t values greater than 9223372036854775807ULL.
        code_ += "  static const int64_t values[] = { {{VALUES}} };";
      }
      auto has_names =
          num_fields && parser_.opts.mini_reflect == IDLOptions::kTypesAndNames;
      if (has_names) {
        code_ += "  static const char * const names[] = {";
        code_ += "    {{NAMES}}";
        code_ += "  };";
      }
      code_ += "  static const flatbuffers::TypeTable tt = {";
      code_ += std::string("    flatbuffers::{{SEQ_TYPE}}, {{NUM_FIELDS}}, ") +
               (num_fields ? "type_codes, " : "nullptr, ") +
               (!type_refs.empty() ? "type_refs, " : "nullptr, ") +
               (!vs.empty() ? "values, " : "nullptr, ") +
               (has_names ? "names" : "nullptr");
      code_ += "  };";
      code_ += "  return &tt;";
      code_ += "}";
      code_ += "";
    }
  
    // Generate an enum declaration,
    // an enum string lookup table,
    // and an enum array of values
  
    void GenEnum(const EnumDef &enum_def) {
      code_.SetValue("ENUM_NAME", Name(enum_def));
      code_.SetValue("BASE_TYPE", GenTypeBasic(enum_def.underlying_type, false));
      code_.SetValue("SEP", "");
  
      GenComment(enum_def.doc_comment);
      code_ += GenEnumDecl(enum_def) + "\\";
      // MSVC doesn't support int64/uint64 enum without explicitly declared enum
      // type. The value 4611686018427387904ULL is truncated to zero with warning:
      // "warning C4309: 'initializing': truncation of constant value".
      auto add_type = parser_.opts.scoped_enums;
      add_type |= (enum_def.underlying_type.base_type == BASE_TYPE_LONG);
      add_type |= (enum_def.underlying_type.base_type == BASE_TYPE_ULONG);
      if (add_type) code_ += " : {{BASE_TYPE}}\\";
      code_ += " {";
  
      for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
        const auto &ev = **it;
        if (!ev.doc_comment.empty()) {
          auto prefix = code_.GetValue("SEP") + "  ";
          GenComment(ev.doc_comment, prefix.c_str());
          code_.SetValue("SEP", "");
        }
        code_.SetValue("KEY", GenEnumValDecl(enum_def, Name(ev)));
        code_.SetValue("VALUE",
                       NumToStringCpp(enum_def.ToString(ev),
                                      enum_def.underlying_type.base_type));
        code_ += "{{SEP}}  {{KEY}} = {{VALUE}}\\";
        code_.SetValue("SEP", ",\n");
      }
      const EnumVal *minv = enum_def.MinValue();
      const EnumVal *maxv = enum_def.MaxValue();
  
      if (parser_.opts.scoped_enums || parser_.opts.prefixed_enums) {
        FLATBUFFERS_ASSERT(minv && maxv);
  
        code_.SetValue("SEP", ",\n");
        if (enum_def.attributes.Lookup("bit_flags")) {
          code_.SetValue("KEY", GenEnumValDecl(enum_def, "NONE"));
          code_.SetValue("VALUE", "0");
          code_ += "{{SEP}}  {{KEY}} = {{VALUE}}\\";
  
          code_.SetValue("KEY", GenEnumValDecl(enum_def, "ANY"));
          code_.SetValue("VALUE",
                         NumToStringCpp(enum_def.AllFlags(),
                                        enum_def.underlying_type.base_type));
          code_ += "{{SEP}}  {{KEY}} = {{VALUE}}\\";
        } else {  // MIN & MAX are useless for bit_flags
          code_.SetValue("KEY", GenEnumValDecl(enum_def, "MIN"));
          code_.SetValue("VALUE", GenEnumValDecl(enum_def, minv->name));
          code_ += "{{SEP}}  {{KEY}} = {{VALUE}}\\";
  
          code_.SetValue("KEY", GenEnumValDecl(enum_def, "MAX"));
          code_.SetValue("VALUE", GenEnumValDecl(enum_def, maxv->name));
          code_ += "{{SEP}}  {{KEY}} = {{VALUE}}\\";
        }
      }
      code_ += "";
      code_ += "};";
  
      if (parser_.opts.scoped_enums && enum_def.attributes.Lookup("bit_flags")) {
        code_ +=
            "FLATBUFFERS_DEFINE_BITMASK_OPERATORS({{ENUM_NAME}}, {{BASE_TYPE}})";
      }
      code_ += "";
  
      // Generate an array of all enumeration values
      auto num_fields = NumToString(enum_def.size());
      code_ += "inline const {{ENUM_NAME}} (&EnumValues{{ENUM_NAME}}())[" +
               num_fields + "] {";
      code_ += "  static const {{ENUM_NAME}} values[] = {";
      for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
        const auto &ev = **it;
        auto value = GetEnumValUse(enum_def, ev);
        auto suffix = *it != enum_def.Vals().back() ? "," : "";
        code_ += "    " + value + suffix;
      }
      code_ += "  };";
      code_ += "  return values;";
      code_ += "}";
      code_ += "";
  
      // Generate a generate string table for enum values.
      // Problem is, if values are very sparse that could generate really big
      // tables. Ideally in that case we generate a map lookup instead, but for
      // the moment we simply don't output a table at all.
      auto range = enum_def.Distance();
      // Average distance between values above which we consider a table
      // "too sparse". Change at will.
      static const uint64_t kMaxSparseness = 5;
      if (range / static_cast<uint64_t>(enum_def.size()) < kMaxSparseness) {
        code_ += "inline const char * const *EnumNames{{ENUM_NAME}}() {";
        code_ += "  static const char * const names[] = {";
  
        auto val = enum_def.Vals().front();
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          auto ev = *it;
          for (auto k = enum_def.Distance(val, ev); k > 1; --k) {
            code_ += "    \"\",";
          }
          val = ev;
          code_ += "    \"" + Name(*ev) + "\",";
        }
        code_ += "    nullptr";
        code_ += "  };";
  
        code_ += "  return names;";
        code_ += "}";
        code_ += "";
  
        code_ += "inline const char *EnumName{{ENUM_NAME}}({{ENUM_NAME}} e) {";
  
        code_ += "  if (e < " + GetEnumValUse(enum_def, *enum_def.MinValue()) +
                 " || e > " + GetEnumValUse(enum_def, *enum_def.MaxValue()) +
                 ") return \"\";";
  
        code_ += "  const size_t index = static_cast<size_t>(e)\\";
        if (enum_def.MinValue()->IsNonZero()) {
          auto vals = GetEnumValUse(enum_def, *enum_def.MinValue());
          code_ += " - static_cast<size_t>(" + vals + ")\\";
        }
        code_ += ";";
  
        code_ += "  return EnumNames{{ENUM_NAME}}()[index];";
        code_ += "}";
        code_ += "";
      } else {
        code_ += "inline const char *EnumName{{ENUM_NAME}}({{ENUM_NAME}} e) {";
  
        code_ += "  switch (e) {";
  
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
          code_ += "    case " + GetEnumValUse(enum_def, ev) + ": return \"" +
                   Name(ev) + "\";";
        }
  
        code_ += "    default: return \"\";";
        code_ += "  }";
  
        code_ += "}";
        code_ += "";
      }
  
      // Generate type traits for unions to map from a type to union enum value.
      if (enum_def.is_union && !enum_def.uses_multiple_type_instances) {
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
  
          if (it == enum_def.Vals().begin()) {
            code_ += "template<typename T> struct {{ENUM_NAME}}Traits {";
          } else {
            auto name = GetUnionElement(ev, true, true);
            code_ += "template<> struct {{ENUM_NAME}}Traits<" + name + "> {";
          }
  
          auto value = GetEnumValUse(enum_def, ev);
          code_ += "  static const {{ENUM_NAME}} enum_value = " + value + ";";
          code_ += "};";
          code_ += "";
        }
      }
  
      if (parser_.opts.generate_object_based_api && enum_def.is_union) {
        // Generate a union type
        code_.SetValue("NAME", Name(enum_def));
        FLATBUFFERS_ASSERT(enum_def.Lookup("NONE"));
        code_.SetValue("NONE", GetEnumValUse(enum_def, *enum_def.Lookup("NONE")));
  
        code_ += "struct {{NAME}}Union {";
        code_ += "  {{NAME}} type;";
        code_ += "  void *value;";
        code_ += "";
        code_ += "  {{NAME}}Union() : type({{NONE}}), value(nullptr) {}";
        code_ += "  {{NAME}}Union({{NAME}}Union&& u) FLATBUFFERS_NOEXCEPT :";
        code_ += "    type({{NONE}}), value(nullptr)";
        code_ += "    { std::swap(type, u.type); std::swap(value, u.value); }";
        code_ += "  {{NAME}}Union(const {{NAME}}Union &) FLATBUFFERS_NOEXCEPT;";
        code_ +=
            "  {{NAME}}Union &operator=(const {{NAME}}Union &u) "
            "FLATBUFFERS_NOEXCEPT";
        code_ +=
            "    { {{NAME}}Union t(u); std::swap(type, t.type); std::swap(value, "
            "t.value); return *this; }";
        code_ +=
            "  {{NAME}}Union &operator=({{NAME}}Union &&u) FLATBUFFERS_NOEXCEPT";
        code_ +=
            "    { std::swap(type, u.type); std::swap(value, u.value); return "
            "*this; }";
        code_ += "  ~{{NAME}}Union() { Reset(); }";
        code_ += "";
        code_ += "  void Reset();";
        code_ += "";
        if (!enum_def.uses_multiple_type_instances) {
          code_ += "#ifndef FLATBUFFERS_CPP98_STL";
          code_ += "  template <typename T>";
          code_ += "  void Set(T&& val) {";
          code_ += "    using RT = typename std::remove_reference<T>::type;";
          code_ += "    Reset();";
          code_ += "    type = {{NAME}}Traits<typename RT::TableType>::enum_value;";
          code_ += "    if (type != {{NONE}}) {";
          code_ += "      value = new RT(std::forward<T>(val));";
          code_ += "    }";
          code_ += "  }";
          code_ += "#endif  // FLATBUFFERS_CPP98_STL";
          code_ += "";
        }
        code_ += "  " + UnionUnPackSignature(enum_def, true) + ";";
        code_ += "  " + UnionPackSignature(enum_def, true) + ";";
        code_ += "";
  
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
          if (ev.IsZero()) { continue; }
  
          const auto native_type =
              NativeName(GetUnionElement(ev, true, true, true),
                         ev.union_type.struct_def, parser_.opts);
          code_.SetValue("NATIVE_TYPE", native_type);
          code_.SetValue("NATIVE_NAME", Name(ev));
          code_.SetValue("NATIVE_ID", GetEnumValUse(enum_def, ev));
  
          code_ += "  {{NATIVE_TYPE}} *As{{NATIVE_NAME}}() {";
          code_ += "    return type == {{NATIVE_ID}} ?";
          code_ += "      reinterpret_cast<{{NATIVE_TYPE}} *>(value) : nullptr;";
          code_ += "  }";
  
          code_ += "  const {{NATIVE_TYPE}} *As{{NATIVE_NAME}}() const {";
          code_ += "    return type == {{NATIVE_ID}} ?";
          code_ +=
              "      reinterpret_cast<const {{NATIVE_TYPE}} *>(value) : nullptr;";
          code_ += "  }";
        }
        code_ += "};";
        code_ += "";
  
        if (parser_.opts.gen_compare) {
          code_ += "";
          code_ +=
              "inline bool operator==(const {{NAME}}Union &lhs, const "
              "{{NAME}}Union &rhs) {";
          code_ += "  if (lhs.type != rhs.type) return false;";
          code_ += "  switch (lhs.type) {";
  
          for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
               ++it) {
            const auto &ev = **it;
            code_.SetValue("NATIVE_ID", GetEnumValUse(enum_def, ev));
            if (ev.IsNonZero()) {
              const auto native_type =
                  NativeName(GetUnionElement(ev, true, true, true),
                             ev.union_type.struct_def, parser_.opts);
              code_.SetValue("NATIVE_TYPE", native_type);
              code_ += "    case {{NATIVE_ID}}: {";
              code_ +=
                  "      return *(reinterpret_cast<const {{NATIVE_TYPE}} "
                  "*>(lhs.value)) ==";
              code_ +=
                  "             *(reinterpret_cast<const {{NATIVE_TYPE}} "
                  "*>(rhs.value));";
              code_ += "    }";
            } else {
              code_ += "    case {{NATIVE_ID}}: {";
              code_ += "      return true;";  // "NONE" enum value.
              code_ += "    }";
            }
          }
          code_ += "    default: {";
          code_ += "      return false;";
          code_ += "    }";
          code_ += "  }";
          code_ += "}";
  
          code_ += "";
          code_ +=
              "inline bool operator!=(const {{NAME}}Union &lhs, const "
              "{{NAME}}Union &rhs) {";
          code_ += "    return !(lhs == rhs);";
          code_ += "}";
          code_ += "";
        }
      }
  
      if (enum_def.is_union) {
        code_ += UnionVerifySignature(enum_def) + ";";
        code_ += UnionVectorVerifySignature(enum_def) + ";";
        code_ += "";
      }
    }
  
    void GenUnionPost(const EnumDef &enum_def) {
      // Generate a verifier function for this union that can be called by the
      // table verifier functions. It uses a switch case to select a specific
      // verifier function to call, this should be safe even if the union type
      // has been corrupted, since the verifiers will simply fail when called
      // on the wrong type.
      code_.SetValue("ENUM_NAME", Name(enum_def));
  
      code_ += "inline " + UnionVerifySignature(enum_def) + " {";
      code_ += "  switch (type) {";
      for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
        const auto &ev = **it;
        code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
  
        if (ev.IsNonZero()) {
          code_.SetValue("TYPE", GetUnionElement(ev, true, true));
          code_ += "    case {{LABEL}}: {";
          auto getptr =
              "      auto ptr = reinterpret_cast<const {{TYPE}} *>(obj);";
          if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
            if (ev.union_type.struct_def->fixed) {
              code_ += "      return verifier.Verify<{{TYPE}}>(static_cast<const "
                       "uint8_t *>(obj), 0);";
            } else {
              code_ += getptr;
              code_ += "      return verifier.VerifyTable(ptr);";
            }
          } else if (ev.union_type.base_type == BASE_TYPE_STRING) {
            code_ += getptr;
            code_ += "      return verifier.VerifyString(ptr);";
          } else {
            FLATBUFFERS_ASSERT(false);
          }
          code_ += "    }";
        } else {
          code_ += "    case {{LABEL}}: {";
          code_ += "      return true;";  // "NONE" enum value.
          code_ += "    }";
        }
      }
      code_ += "    default: return false;";
      code_ += "  }";
      code_ += "}";
      code_ += "";
  
      code_ += "inline " + UnionVectorVerifySignature(enum_def) + " {";
      code_ += "  if (!values || !types) return !values && !types;";
      code_ += "  if (values->size() != types->size()) return false;";
      code_ += "  for (flatbuffers::uoffset_t i = 0; i < values->size(); ++i) {";
      code_ += "    if (!Verify" + Name(enum_def) + "(";
      code_ += "        verifier,  values->Get(i), types->GetEnum<" +
               Name(enum_def) + ">(i))) {";
      code_ += "      return false;";
      code_ += "    }";
      code_ += "  }";
      code_ += "  return true;";
      code_ += "}";
      code_ += "";
  
      if (parser_.opts.generate_object_based_api) {
        // Generate union Unpack() and Pack() functions.
        code_ += "inline " + UnionUnPackSignature(enum_def, false) + " {";
        code_ += "  switch (type) {";
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
          if (ev.IsZero()) { continue; }
  
          code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
          code_.SetValue("TYPE", GetUnionElement(ev, true, true));
          code_ += "    case {{LABEL}}: {";
          code_ += "      auto ptr = reinterpret_cast<const {{TYPE}} *>(obj);";
          if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
            if (ev.union_type.struct_def->fixed) {
              code_ += "      return new " +
                       WrapInNameSpace(*ev.union_type.struct_def) + "(*ptr);";
            } else {
              code_ += "      return ptr->UnPack(resolver);";
            }
          } else if (ev.union_type.base_type == BASE_TYPE_STRING) {
            code_ += "      return new std::string(ptr->c_str(), ptr->size());";
          } else {
            FLATBUFFERS_ASSERT(false);
          }
          code_ += "    }";
        }
        code_ += "    default: return nullptr;";
        code_ += "  }";
        code_ += "}";
        code_ += "";
  
        code_ += "inline " + UnionPackSignature(enum_def, false) + " {";
        code_ += "  switch (type) {";
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          auto &ev = **it;
          if (ev.IsZero()) { continue; }
  
          code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
          code_.SetValue("TYPE",
                         NativeName(GetUnionElement(ev, true, true, true),
                                    ev.union_type.struct_def, parser_.opts));
          code_.SetValue("NAME", GetUnionElement(ev, false, true));
          code_ += "    case {{LABEL}}: {";
          code_ += "      auto ptr = reinterpret_cast<const {{TYPE}} *>(value);";
          if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
            if (ev.union_type.struct_def->fixed) {
              code_ += "      return _fbb.CreateStruct(*ptr).Union();";
            } else {
              code_ +=
                  "      return Create{{NAME}}(_fbb, ptr, _rehasher).Union();";
            }
          } else if (ev.union_type.base_type == BASE_TYPE_STRING) {
            code_ += "      return _fbb.CreateString(*ptr).Union();";
          } else {
            FLATBUFFERS_ASSERT(false);
          }
          code_ += "    }";
        }
        code_ += "    default: return 0;";
        code_ += "  }";
        code_ += "}";
        code_ += "";
  
        // Union copy constructor
        code_ +=
            "inline {{ENUM_NAME}}Union::{{ENUM_NAME}}Union(const "
            "{{ENUM_NAME}}Union &u) FLATBUFFERS_NOEXCEPT : type(u.type), "
            "value(nullptr) {";
        code_ += "  switch (type) {";
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
          if (ev.IsZero()) { continue; }
          code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
          code_.SetValue("TYPE",
                         NativeName(GetUnionElement(ev, true, true, true),
                                    ev.union_type.struct_def, parser_.opts));
          code_ += "    case {{LABEL}}: {";
          bool copyable = true;
          if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
            // Don't generate code to copy if table is not copyable.
            // TODO(wvo): make tables copyable instead.
            for (auto fit = ev.union_type.struct_def->fields.vec.begin();
                 fit != ev.union_type.struct_def->fields.vec.end(); ++fit) {
              const auto &field = **fit;
              if (!field.deprecated && field.value.type.struct_def &&
                  !field.native_inline) {
                copyable = false;
                break;
              }
            }
          }
          if (copyable) {
            code_ +=
                "      value = new {{TYPE}}(*reinterpret_cast<{{TYPE}} *>"
                "(u.value));";
          } else {
            code_ +=
                "      FLATBUFFERS_ASSERT(false);  // {{TYPE}} not copyable.";
          }
          code_ += "      break;";
          code_ += "    }";
        }
        code_ += "    default:";
        code_ += "      break;";
        code_ += "  }";
        code_ += "}";
        code_ += "";
  
        // Union Reset() function.
        FLATBUFFERS_ASSERT(enum_def.Lookup("NONE"));
        code_.SetValue("NONE", GetEnumValUse(enum_def, *enum_def.Lookup("NONE")));
  
        code_ += "inline void {{ENUM_NAME}}Union::Reset() {";
        code_ += "  switch (type) {";
        for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
             ++it) {
          const auto &ev = **it;
          if (ev.IsZero()) { continue; }
          code_.SetValue("LABEL", GetEnumValUse(enum_def, ev));
          code_.SetValue("TYPE",
                         NativeName(GetUnionElement(ev, true, true, true),
                                    ev.union_type.struct_def, parser_.opts));
          code_ += "    case {{LABEL}}: {";
          code_ += "      auto ptr = reinterpret_cast<{{TYPE}} *>(value);";
          code_ += "      delete ptr;";
          code_ += "      break;";
          code_ += "    }";
        }
        code_ += "    default: break;";
        code_ += "  }";
        code_ += "  value = nullptr;";
        code_ += "  type = {{NONE}};";
        code_ += "}";
        code_ += "";
      }
    }
  
    // Generates a value with optionally a cast applied if the field has a
    // different underlying type from its interface type (currently only the
    // case for enums. "from" specify the direction, true meaning from the
    // underlying type to the interface type.
    std::string GenUnderlyingCast(const FieldDef &field, bool from,
                                  const std::string &val) {
      if (from && field.value.type.base_type == BASE_TYPE_BOOL) {
        return val + " != 0";
      } else if ((field.value.type.enum_def &&
                  IsScalar(field.value.type.base_type)) ||
                 field.value.type.base_type == BASE_TYPE_BOOL) {
        return "static_cast<" + GenTypeBasic(field.value.type, from) + ">(" +
               val + ")";
      } else {
        return val;
      }
    }
  
    std::string GenFieldOffsetName(const FieldDef &field) {
      std::string uname = Name(field);
      std::transform(uname.begin(), uname.end(), uname.begin(), ToUpper);
      return "VT_" + uname;
    }
  
    void GenFullyQualifiedNameGetter(const StructDef &struct_def,
                                     const std::string &name) {
      if (!parser_.opts.generate_name_strings) { return; }
      auto fullname = struct_def.defined_namespace->GetFullyQualifiedName(name);
      code_.SetValue("NAME", fullname);
      code_.SetValue("CONSTEXPR", "FLATBUFFERS_CONSTEXPR");
      code_ += "  static {{CONSTEXPR}} const char *GetFullyQualifiedName() {";
      code_ += "    return \"{{NAME}}\";";
      code_ += "  }";
    }
  
    std::string GenDefaultConstant(const FieldDef &field) {
      if (IsFloat(field.value.type.base_type))
        return float_const_gen_.GenFloatConstant(field);
      else
        return NumToStringCpp(field.value.constant, field.value.type.base_type);
    }
  
    std::string GetDefaultScalarValue(const FieldDef &field, bool is_ctor) {
      if (field.value.type.enum_def && IsScalar(field.value.type.base_type)) {
        auto ev = field.value.type.enum_def->FindByValue(field.value.constant);
        if (ev) {
          return WrapInNameSpace(field.value.type.enum_def->defined_namespace,
                                 GetEnumValUse(*field.value.type.enum_def, *ev));
        } else {
          return GenUnderlyingCast(
              field, true,
              NumToStringCpp(field.value.constant, field.value.type.base_type));
        }
      } else if (field.value.type.base_type == BASE_TYPE_BOOL) {
        return field.value.constant == "0" ? "false" : "true";
      } else if (field.attributes.Lookup("cpp_type")) {
        if (is_ctor) {
          if (PtrType(&field) == "naked") {
            return "nullptr";
          } else {
            return "";
          }
        } else {
          return "0";
        }
      } else {
        return GenDefaultConstant(field);
      }
    }
  
    void GenParam(const FieldDef &field, bool direct, const char *prefix) {
      code_.SetValue("PRE", prefix);
      code_.SetValue("PARAM_NAME", Name(field));
      if (direct && field.value.type.base_type == BASE_TYPE_STRING) {
        code_.SetValue("PARAM_TYPE", "const char *");
        code_.SetValue("PARAM_VALUE", "nullptr");
      } else if (direct && field.value.type.base_type == BASE_TYPE_VECTOR) {
        const auto vtype = field.value.type.VectorType();
        std::string type;
        if (IsStruct(vtype)) {
          type = WrapInNameSpace(*vtype.struct_def);
        } else {
          type = GenTypeWire(vtype, "", false);
        }
        code_.SetValue("PARAM_TYPE", "const std::vector<" + type + "> *");
        code_.SetValue("PARAM_VALUE", "nullptr");
      } else {
        code_.SetValue("PARAM_TYPE", GenTypeWire(field.value.type, " ", true));
        code_.SetValue("PARAM_VALUE", GetDefaultScalarValue(field, false));
      }
      code_ += "{{PRE}}{{PARAM_TYPE}}{{PARAM_NAME}} = {{PARAM_VALUE}}\\";
    }
  
    // Generate a member, including a default value for scalars and raw pointers.
    void GenMember(const FieldDef &field) {
      if (!field.deprecated &&  // Deprecated fields won't be accessible.
          field.value.type.base_type != BASE_TYPE_UTYPE &&
          (field.value.type.base_type != BASE_TYPE_VECTOR ||
           field.value.type.element != BASE_TYPE_UTYPE)) {
        auto type = GenTypeNative(field.value.type, false, field);
        auto cpp_type = field.attributes.Lookup("cpp_type");
        auto full_type =
            (cpp_type
                 ? (field.value.type.base_type == BASE_TYPE_VECTOR
                        ? "std::vector<" +
                              GenTypeNativePtr(cpp_type->constant, &field,
                                               false) +
                              "> "
                        : GenTypeNativePtr(cpp_type->constant, &field, false))
                 : type + " ");
        code_.SetValue("FIELD_TYPE", full_type);
        code_.SetValue("FIELD_NAME", Name(field));
        code_ += "  {{FIELD_TYPE}}{{FIELD_NAME}};";
      }
    }
  
    // Generate the default constructor for this struct. Properly initialize all
    // scalar members with default values.
    void GenDefaultConstructor(const StructDef &struct_def) {
      std::string initializer_list;
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (!field.deprecated &&  // Deprecated fields won't be accessible.
            field.value.type.base_type != BASE_TYPE_UTYPE) {
          auto cpp_type = field.attributes.Lookup("cpp_type");
          auto native_default = field.attributes.Lookup("native_default");
          // Scalar types get parsed defaults, raw pointers get nullptrs.
          if (IsScalar(field.value.type.base_type)) {
            if (!initializer_list.empty()) { initializer_list += ",\n        "; }
            initializer_list += Name(field);
            initializer_list +=
                "(" +
                (native_default ? std::string(native_default->constant)
                                : GetDefaultScalarValue(field, true)) +
                ")";
          } else if (field.value.type.base_type == BASE_TYPE_STRUCT) {
            if (IsStruct(field.value.type)) {
              if (native_default) {
                if (!initializer_list.empty()) {
                  initializer_list += ",\n        ";
                }
                initializer_list +=
                    Name(field) + "(" + native_default->constant + ")";
              }
            }
          } else if (cpp_type && field.value.type.base_type != BASE_TYPE_VECTOR) {
            if (!initializer_list.empty()) { initializer_list += ",\n        "; }
            initializer_list += Name(field) + "(0)";
          }
        }
      }
      if (!initializer_list.empty()) {
        initializer_list = "\n      : " + initializer_list;
      }
  
      code_.SetValue("NATIVE_NAME",
                     NativeName(Name(struct_def), &struct_def, parser_.opts));
      code_.SetValue("INIT_LIST", initializer_list);
  
      code_ += "  {{NATIVE_NAME}}(){{INIT_LIST}} {";
      code_ += "  }";
    }
  
    void GenCompareOperator(const StructDef &struct_def,
                            std::string accessSuffix = "") {
      std::string compare_op;
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (!field.deprecated &&  // Deprecated fields won't be accessible.
            field.value.type.base_type != BASE_TYPE_UTYPE &&
            (field.value.type.base_type != BASE_TYPE_VECTOR ||
             field.value.type.element != BASE_TYPE_UTYPE)) {
          if (!compare_op.empty()) { compare_op += " &&\n      "; }
          auto accessor = Name(field) + accessSuffix;
          compare_op += "(lhs." + accessor + " == rhs." + accessor + ")";
        }
      }
  
      std::string cmp_lhs;
      std::string cmp_rhs;
      if (compare_op.empty()) {
        cmp_lhs = "";
        cmp_rhs = "";
        compare_op = "  return true;";
      } else {
        cmp_lhs = "lhs";
        cmp_rhs = "rhs";
        compare_op = "  return\n      " + compare_op + ";";
      }
  
      code_.SetValue("CMP_OP", compare_op);
      code_.SetValue("CMP_LHS", cmp_lhs);
      code_.SetValue("CMP_RHS", cmp_rhs);
      code_ += "";
      code_ +=
          "inline bool operator==(const {{NATIVE_NAME}} &{{CMP_LHS}}, const "
          "{{NATIVE_NAME}} &{{CMP_RHS}}) {";
      code_ += "{{CMP_OP}}";
      code_ += "}";
  
      code_ += "";
      code_ +=
          "inline bool operator!=(const {{NATIVE_NAME}} &lhs, const "
          "{{NATIVE_NAME}} &rhs) {";
      code_ += "    return !(lhs == rhs);";
      code_ += "}";
      code_ += "";
    }
  
    void GenOperatorNewDelete(const StructDef &struct_def) {
      if (auto native_custom_alloc =
              struct_def.attributes.Lookup("native_custom_alloc")) {
        code_ += "  inline void *operator new (std::size_t count) {";
        code_ += "    return " + native_custom_alloc->constant +
                 "<{{NATIVE_NAME}}>().allocate(count / sizeof({{NATIVE_NAME}}));";
        code_ += "  }";
        code_ += "  inline void operator delete (void *ptr) {";
        code_ += "    return " + native_custom_alloc->constant +
                 "<{{NATIVE_NAME}}>().deallocate(static_cast<{{NATIVE_NAME}}*>("
                 "ptr),1);";
        code_ += "  }";
      }
    }
  
    void GenNativeTable(const StructDef &struct_def) {
      const auto native_name =
          NativeName(Name(struct_def), &struct_def, parser_.opts);
      code_.SetValue("STRUCT_NAME", Name(struct_def));
      code_.SetValue("NATIVE_NAME", native_name);
  
      // Generate a C++ object that can hold an unpacked version of this table.
      code_ += "struct {{NATIVE_NAME}} : public flatbuffers::NativeTable {";
      code_ += "  typedef {{STRUCT_NAME}} TableType;";
      GenFullyQualifiedNameGetter(struct_def, native_name);
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        GenMember(**it);
      }
      GenOperatorNewDelete(struct_def);
      GenDefaultConstructor(struct_def);
      code_ += "};";
      if (parser_.opts.gen_compare) GenCompareOperator(struct_def);
      code_ += "";
    }
  
    // Generate the code to call the appropriate Verify function(s) for a field.
    void GenVerifyCall(const FieldDef &field, const char *prefix) {
      code_.SetValue("PRE", prefix);
      code_.SetValue("NAME", Name(field));
      code_.SetValue("REQUIRED", field.required ? "Required" : "");
      code_.SetValue("SIZE", GenTypeSize(field.value.type));
      code_.SetValue("OFFSET", GenFieldOffsetName(field));
      if (IsScalar(field.value.type.base_type) || IsStruct(field.value.type)) {
        code_ +=
            "{{PRE}}VerifyField{{REQUIRED}}<{{SIZE}}>(verifier, {{OFFSET}})\\";
      } else {
        code_ += "{{PRE}}VerifyOffset{{REQUIRED}}(verifier, {{OFFSET}})\\";
      }
  
      switch (field.value.type.base_type) {
        case BASE_TYPE_UNION: {
          code_.SetValue("ENUM_NAME", field.value.type.enum_def->name);
          code_.SetValue("SUFFIX", UnionTypeFieldSuffix());
          code_ +=
              "{{PRE}}Verify{{ENUM_NAME}}(verifier, {{NAME}}(), "
              "{{NAME}}{{SUFFIX}}())\\";
          break;
        }
        case BASE_TYPE_STRUCT: {
          if (!field.value.type.struct_def->fixed) {
            code_ += "{{PRE}}verifier.VerifyTable({{NAME}}())\\";
          }
          break;
        }
        case BASE_TYPE_STRING: {
          code_ += "{{PRE}}verifier.VerifyString({{NAME}}())\\";
          break;
        }
        case BASE_TYPE_VECTOR: {
          code_ += "{{PRE}}verifier.VerifyVector({{NAME}}())\\";
  
          switch (field.value.type.element) {
            case BASE_TYPE_STRING: {
              code_ += "{{PRE}}verifier.VerifyVectorOfStrings({{NAME}}())\\";
              break;
            }
            case BASE_TYPE_STRUCT: {
              if (!field.value.type.struct_def->fixed) {
                code_ += "{{PRE}}verifier.VerifyVectorOfTables({{NAME}}())\\";
              }
              break;
            }
            case BASE_TYPE_UNION: {
              code_.SetValue("ENUM_NAME", field.value.type.enum_def->name);
              code_ +=
                  "{{PRE}}Verify{{ENUM_NAME}}Vector(verifier, {{NAME}}(), "
                  "{{NAME}}_type())\\";
              break;
            }
            default: break;
          }
          break;
        }
        default: { break; }
      }
    }
  
    // Generate CompareWithValue method for a key field.
    void GenKeyFieldMethods(const FieldDef &field) {
      FLATBUFFERS_ASSERT(field.key);
      const bool is_string = (field.value.type.base_type == BASE_TYPE_STRING);
  
      code_ += "  bool KeyCompareLessThan(const {{STRUCT_NAME}} *o) const {";
      if (is_string) {
        // use operator< of flatbuffers::String
        code_ += "    return *{{FIELD_NAME}}() < *o->{{FIELD_NAME}}();";
      } else {
        code_ += "    return {{FIELD_NAME}}() < o->{{FIELD_NAME}}();";
      }
      code_ += "  }";
  
      if (is_string) {
        code_ += "  int KeyCompareWithValue(const char *val) const {";
        code_ += "    return strcmp({{FIELD_NAME}}()->c_str(), val);";
        code_ += "  }";
      } else {
        FLATBUFFERS_ASSERT(IsScalar(field.value.type.base_type));
        auto type = GenTypeBasic(field.value.type, false);
        if (parser_.opts.scoped_enums && field.value.type.enum_def &&
            IsScalar(field.value.type.base_type)) {
          type = GenTypeGet(field.value.type, " ", "const ", " *", true);
        }
        // Returns {field<val: -1, field==val: 0, field>val: +1}.
        code_.SetValue("KEY_TYPE", type);
        code_ += "  int KeyCompareWithValue({{KEY_TYPE}} val) const {";
        code_ +=
            "    return static_cast<int>({{FIELD_NAME}}() > val) - "
            "static_cast<int>({{FIELD_NAME}}() < val);";
        code_ += "  }";
      }
    }
  
    // Generate an accessor struct, builder structs & function for a table.
    void GenTable(const StructDef &struct_def) {
      if (parser_.opts.generate_object_based_api) { GenNativeTable(struct_def); }
  
      // Generate an accessor struct, with methods of the form:
      // type name() const { return GetField<type>(offset, defaultval); }
      GenComment(struct_def.doc_comment);
  
      code_.SetValue("STRUCT_NAME", Name(struct_def));
      code_ +=
          "struct {{STRUCT_NAME}} FLATBUFFERS_FINAL_CLASS"
          " : private flatbuffers::Table {";
      if (parser_.opts.generate_object_based_api) {
        code_ += "  typedef {{NATIVE_NAME}} NativeTableType;";
      }
      if (parser_.opts.mini_reflect != IDLOptions::kNone) {
        code_ +=
            "  static const flatbuffers::TypeTable *MiniReflectTypeTable() {";
        code_ += "    return {{STRUCT_NAME}}TypeTable();";
        code_ += "  }";
      }
  
      GenFullyQualifiedNameGetter(struct_def, Name(struct_def));
  
      // Generate field id constants.
      if (struct_def.fields.vec.size() > 0) {
        // We need to add a trailing comma to all elements except the last one as
        // older versions of gcc complain about this.
        code_.SetValue("SEP", "");
        code_ +=
            "  enum FlatBuffersVTableOffset FLATBUFFERS_VTABLE_UNDERLYING_TYPE {";
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (field.deprecated) {
            // Deprecated fields won't be accessible.
            continue;
          }
  
          code_.SetValue("OFFSET_NAME", GenFieldOffsetName(field));
          code_.SetValue("OFFSET_VALUE", NumToString(field.value.offset));
          code_ += "{{SEP}}    {{OFFSET_NAME}} = {{OFFSET_VALUE}}\\";
          code_.SetValue("SEP", ",\n");
        }
        code_ += "";
        code_ += "  };";
      }
  
      // Generate the accessors.
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (field.deprecated) {
          // Deprecated fields won't be accessible.
          continue;
        }
  
        const bool is_struct = IsStruct(field.value.type);
        const bool is_scalar = IsScalar(field.value.type.base_type);
        code_.SetValue("FIELD_NAME", Name(field));
  
        // Call a different accessor for pointers, that indirects.
        std::string accessor = "";
        if (is_scalar) {
          accessor = "GetField<";
        } else if (is_struct) {
          accessor = "GetStruct<";
        } else {
          accessor = "GetPointer<";
        }
        auto offset_str = GenFieldOffsetName(field);
        auto offset_type =
            GenTypeGet(field.value.type, "", "const ", " *", false);
  
        auto call = accessor + offset_type + ">(" + offset_str;
        // Default value as second arg for non-pointer types.
        if (is_scalar) { call += ", " + GenDefaultConstant(field); }
        call += ")";
  
        std::string afterptr = " *" + NullableExtension();
        GenComment(field.doc_comment, "  ");
        code_.SetValue("FIELD_TYPE", GenTypeGet(field.value.type, " ", "const ",
                                                afterptr.c_str(), true));
        code_.SetValue("FIELD_VALUE", GenUnderlyingCast(field, true, call));
        code_.SetValue("NULLABLE_EXT", NullableExtension());
  
        code_ += "  {{FIELD_TYPE}}{{FIELD_NAME}}() const {";
        code_ += "    return {{FIELD_VALUE}};";
        code_ += "  }";
  
        if (field.value.type.base_type == BASE_TYPE_UNION) {
          auto u = field.value.type.enum_def;
  
          if (!field.value.type.enum_def->uses_multiple_type_instances)
            code_ +=
                "  template<typename T> "
                "const T *{{NULLABLE_EXT}}{{FIELD_NAME}}_as() const;";
  
          for (auto u_it = u->Vals().begin(); u_it != u->Vals().end(); ++u_it) {
            auto &ev = **u_it;
            if (ev.union_type.base_type == BASE_TYPE_NONE) { continue; }
            auto full_struct_name = GetUnionElement(ev, true, true);
  
            // @TODO: Mby make this decisions more universal? How?
            code_.SetValue("U_GET_TYPE",
                           EscapeKeyword(field.name + UnionTypeFieldSuffix()));
            code_.SetValue(
                "U_ELEMENT_TYPE",
                WrapInNameSpace(u->defined_namespace, GetEnumValUse(*u, ev)));
            code_.SetValue("U_FIELD_TYPE", "const " + full_struct_name + " *");
            code_.SetValue("U_FIELD_NAME", Name(field) + "_as_" + Name(ev));
            code_.SetValue("U_NULLABLE", NullableExtension());
  
            // `const Type *union_name_asType() const` accessor.
            code_ += "  {{U_FIELD_TYPE}}{{U_NULLABLE}}{{U_FIELD_NAME}}() const {";
            code_ +=
                "    return {{U_GET_TYPE}}() == {{U_ELEMENT_TYPE}} ? "
                "static_cast<{{U_FIELD_TYPE}}>({{FIELD_NAME}}()) "
                ": nullptr;";
            code_ += "  }";
          }
        }
  
        if (parser_.opts.mutable_buffer) {
          if (is_scalar) {
            const auto type = GenTypeWire(field.value.type, "", false);
            code_.SetValue("SET_FN", "SetField<" + type + ">");
            code_.SetValue("OFFSET_NAME", offset_str);
            code_.SetValue("FIELD_TYPE", GenTypeBasic(field.value.type, true));
            code_.SetValue("FIELD_VALUE",
                           GenUnderlyingCast(field, false, "_" + Name(field)));
            code_.SetValue("DEFAULT_VALUE", GenDefaultConstant(field));
  
            code_ +=
                "  bool mutate_{{FIELD_NAME}}({{FIELD_TYPE}} "
                "_{{FIELD_NAME}}) {";
            code_ +=
                "    return {{SET_FN}}({{OFFSET_NAME}}, {{FIELD_VALUE}}, "
                "{{DEFAULT_VALUE}});";
            code_ += "  }";
          } else {
            auto postptr = " *" + NullableExtension();
            auto type =
                GenTypeGet(field.value.type, " ", "", postptr.c_str(), true);
            auto underlying = accessor + type + ">(" + offset_str + ")";
            code_.SetValue("FIELD_TYPE", type);
            code_.SetValue("FIELD_VALUE",
                           GenUnderlyingCast(field, true, underlying));
  
            code_ += "  {{FIELD_TYPE}}mutable_{{FIELD_NAME}}() {";
            code_ += "    return {{FIELD_VALUE}};";
            code_ += "  }";
          }
        }
  
        auto nested = field.attributes.Lookup("nested_flatbuffer");
        if (nested) {
          std::string qualified_name = nested->constant;
          auto nested_root = parser_.LookupStruct(nested->constant);
          if (nested_root == nullptr) {
            qualified_name = parser_.current_namespace_->GetFullyQualifiedName(
                nested->constant);
            nested_root = parser_.LookupStruct(qualified_name);
          }
          FLATBUFFERS_ASSERT(nested_root);  // Guaranteed to exist by parser.
          (void)nested_root;
          code_.SetValue("CPP_NAME", TranslateNameSpace(qualified_name));
  
          code_ += "  const {{CPP_NAME}} *{{FIELD_NAME}}_nested_root() const {";
          code_ +=
              "    return "
              "flatbuffers::GetRoot<{{CPP_NAME}}>({{FIELD_NAME}}()->Data());";
          code_ += "  }";
        }
  
        if (field.flexbuffer) {
          code_ +=
              "  flexbuffers::Reference {{FIELD_NAME}}_flexbuffer_root()"
              " const {";
          // Both Data() and size() are const-methods, therefore call order
          // doesn't matter.
          code_ +=
              "    return flexbuffers::GetRoot({{FIELD_NAME}}()->Data(), "
              "{{FIELD_NAME}}()->size());";
          code_ += "  }";
        }
  
        // Generate a comparison function for this field if it is a key.
        if (field.key) { GenKeyFieldMethods(field); }
      }
  
      // Generate a verifier function that can check a buffer from an untrusted
      // source will never cause reads outside the buffer.
      code_ += "  bool Verify(flatbuffers::Verifier &verifier) const {";
      code_ += "    return VerifyTableStart(verifier)\\";
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (field.deprecated) { continue; }
        GenVerifyCall(field, " &&\n           ");
      }
  
      code_ += " &&\n           verifier.EndTable();";
      code_ += "  }";
  
      if (parser_.opts.generate_object_based_api) {
        // Generate the UnPack() pre declaration.
        code_ +=
            "  " + TableUnPackSignature(struct_def, true, parser_.opts) + ";";
        code_ +=
            "  " + TableUnPackToSignature(struct_def, true, parser_.opts) + ";";
        code_ += "  " + TablePackSignature(struct_def, true, parser_.opts) + ";";
      }
  
      code_ += "};";  // End of table.
      code_ += "";
  
      // Explicit specializations for union accessors
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (field.deprecated || field.value.type.base_type != BASE_TYPE_UNION) {
          continue;
        }
  
        auto u = field.value.type.enum_def;
        if (u->uses_multiple_type_instances) continue;
  
        code_.SetValue("FIELD_NAME", Name(field));
  
        for (auto u_it = u->Vals().begin(); u_it != u->Vals().end(); ++u_it) {
          auto &ev = **u_it;
          if (ev.union_type.base_type == BASE_TYPE_NONE) { continue; }
  
          auto full_struct_name = GetUnionElement(ev, true, true);
  
          code_.SetValue(
              "U_ELEMENT_TYPE",
              WrapInNameSpace(u->defined_namespace, GetEnumValUse(*u, ev)));
          code_.SetValue("U_FIELD_TYPE", "const " + full_struct_name + " *");
          code_.SetValue("U_ELEMENT_NAME", full_struct_name);
          code_.SetValue("U_FIELD_NAME", Name(field) + "_as_" + Name(ev));
  
          // `template<> const T *union_name_as<T>() const` accessor.
          code_ +=
              "template<> "
              "inline {{U_FIELD_TYPE}}{{STRUCT_NAME}}::{{FIELD_NAME}}_as"
              "<{{U_ELEMENT_NAME}}>() const {";
          code_ += "  return {{U_FIELD_NAME}}();";
          code_ += "}";
          code_ += "";
        }
      }
  
      GenBuilders(struct_def);
  
      if (parser_.opts.generate_object_based_api) {
        // Generate a pre-declaration for a CreateX method that works with an
        // unpacked C++ object.
        code_ += TableCreateSignature(struct_def, true, parser_.opts) + ";";
        code_ += "";
      }
    }
  
    void GenBuilders(const StructDef &struct_def) {
      code_.SetValue("STRUCT_NAME", Name(struct_def));
  
      // Generate a builder struct:
      code_ += "struct {{STRUCT_NAME}}Builder {";
      code_ += "  flatbuffers::FlatBufferBuilder &fbb_;";
      code_ += "  flatbuffers::uoffset_t start_;";
  
      bool has_string_or_vector_fields = false;
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (!field.deprecated) {
          const bool is_scalar = IsScalar(field.value.type.base_type);
          const bool is_string = field.value.type.base_type == BASE_TYPE_STRING;
          const bool is_vector = field.value.type.base_type == BASE_TYPE_VECTOR;
          if (is_string || is_vector) { has_string_or_vector_fields = true; }
  
          std::string offset = GenFieldOffsetName(field);
          std::string name = GenUnderlyingCast(field, false, Name(field));
          std::string value = is_scalar ? GenDefaultConstant(field) : "";
  
          // Generate accessor functions of the form:
          // void add_name(type name) {
          //   fbb_.AddElement<type>(offset, name, default);
          // }
          code_.SetValue("FIELD_NAME", Name(field));
          code_.SetValue("FIELD_TYPE", GenTypeWire(field.value.type, " ", true));
          code_.SetValue("ADD_OFFSET", Name(struct_def) + "::" + offset);
          code_.SetValue("ADD_NAME", name);
          code_.SetValue("ADD_VALUE", value);
          if (is_scalar) {
            const auto type = GenTypeWire(field.value.type, "", false);
            code_.SetValue("ADD_FN", "AddElement<" + type + ">");
          } else if (IsStruct(field.value.type)) {
            code_.SetValue("ADD_FN", "AddStruct");
          } else {
            code_.SetValue("ADD_FN", "AddOffset");
          }
  
          code_ += "  void add_{{FIELD_NAME}}({{FIELD_TYPE}}{{FIELD_NAME}}) {";
          code_ += "    fbb_.{{ADD_FN}}(\\";
          if (is_scalar) {
            code_ += "{{ADD_OFFSET}}, {{ADD_NAME}}, {{ADD_VALUE}});";
          } else {
            code_ += "{{ADD_OFFSET}}, {{ADD_NAME}});";
          }
          code_ += "  }";
        }
      }
  
      // Builder constructor
      code_ +=
          "  explicit {{STRUCT_NAME}}Builder(flatbuffers::FlatBufferBuilder "
          "&_fbb)";
      code_ += "        : fbb_(_fbb) {";
      code_ += "    start_ = fbb_.StartTable();";
      code_ += "  }";
  
      // Assignment operator;
      code_ +=
          "  {{STRUCT_NAME}}Builder &operator="
          "(const {{STRUCT_NAME}}Builder &);";
  
      // Finish() function.
      code_ += "  flatbuffers::Offset<{{STRUCT_NAME}}> Finish() {";
      code_ += "    const auto end = fbb_.EndTable(start_);";
      code_ += "    auto o = flatbuffers::Offset<{{STRUCT_NAME}}>(end);";
  
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (!field.deprecated && field.required) {
          code_.SetValue("FIELD_NAME", Name(field));
          code_.SetValue("OFFSET_NAME", GenFieldOffsetName(field));
          code_ += "    fbb_.Required(o, {{STRUCT_NAME}}::{{OFFSET_NAME}});";
        }
      }
      code_ += "    return o;";
      code_ += "  }";
      code_ += "};";
      code_ += "";
  
      // Generate a convenient CreateX function that uses the above builder
      // to create a table in one go.
      code_ +=
          "inline flatbuffers::Offset<{{STRUCT_NAME}}> "
          "Create{{STRUCT_NAME}}(";
      code_ += "    flatbuffers::FlatBufferBuilder &_fbb\\";
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        if (!field.deprecated) { GenParam(field, false, ",\n    "); }
      }
      code_ += ") {";
  
      code_ += "  {{STRUCT_NAME}}Builder builder_(_fbb);";
      for (size_t size = struct_def.sortbysize ? sizeof(largest_scalar_t) : 1;
           size; size /= 2) {
        for (auto it = struct_def.fields.vec.rbegin();
             it != struct_def.fields.vec.rend(); ++it) {
          const auto &field = **it;
          if (!field.deprecated && (!struct_def.sortbysize ||
                                    size == SizeOf(field.value.type.base_type))) {
            code_.SetValue("FIELD_NAME", Name(field));
            code_ += "  builder_.add_{{FIELD_NAME}}({{FIELD_NAME}});";
          }
        }
      }
      code_ += "  return builder_.Finish();";
      code_ += "}";
      code_ += "";
  
      // Generate a CreateXDirect function with vector types as parameters
      if (has_string_or_vector_fields) {
        code_ +=
            "inline flatbuffers::Offset<{{STRUCT_NAME}}> "
            "Create{{STRUCT_NAME}}Direct(";
        code_ += "    flatbuffers::FlatBufferBuilder &_fbb\\";
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (!field.deprecated) { GenParam(field, true, ",\n    "); }
        }
        // Need to call "Create" with the struct namespace.
        const auto qualified_create_name =
            struct_def.defined_namespace->GetFullyQualifiedName("Create");
        code_.SetValue("CREATE_NAME", TranslateNameSpace(qualified_create_name));
        code_ += ") {";
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (!field.deprecated) {
            code_.SetValue("FIELD_NAME", Name(field));
            if (field.value.type.base_type == BASE_TYPE_STRING) {
              if (!field.shared) {
                code_.SetValue("CREATE_STRING", "CreateString");
              } else {
                code_.SetValue("CREATE_STRING", "CreateSharedString");
              }
              code_ +=
                  "  auto {{FIELD_NAME}}__ = {{FIELD_NAME}} ? "
                  "_fbb.{{CREATE_STRING}}({{FIELD_NAME}}) : 0;";
            } else if (field.value.type.base_type == BASE_TYPE_VECTOR) {
              code_ += "  auto {{FIELD_NAME}}__ = {{FIELD_NAME}} ? \\";
              const auto vtype = field.value.type.VectorType();
              if (IsStruct(vtype)) {
                const auto type = WrapInNameSpace(*vtype.struct_def);
                code_ += "_fbb.CreateVectorOfStructs<" + type + ">\\";
              } else {
                const auto type = GenTypeWire(vtype, "", false);
                code_ += "_fbb.CreateVector<" + type + ">\\";
              }
              code_ += "(*{{FIELD_NAME}}) : 0;";
            }
          }
        }
        code_ += "  return {{CREATE_NAME}}{{STRUCT_NAME}}(";
        code_ += "      _fbb\\";
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (!field.deprecated) {
            code_.SetValue("FIELD_NAME", Name(field));
            code_ += ",\n      {{FIELD_NAME}}\\";
            if (field.value.type.base_type == BASE_TYPE_STRING ||
                field.value.type.base_type == BASE_TYPE_VECTOR) {
              code_ += "__\\";
            }
          }
        }
        code_ += ");";
        code_ += "}";
        code_ += "";
      }
    }
  
    std::string GenUnionUnpackVal(const FieldDef &afield,
                                  const char *vec_elem_access,
                                  const char *vec_type_access) {
      return afield.value.type.enum_def->name + "Union::UnPack(" + "_e" +
             vec_elem_access + ", " +
             EscapeKeyword(afield.name + UnionTypeFieldSuffix()) + "()" +
             vec_type_access + ", _resolver)";
    }
  
    std::string GenUnpackVal(const Type &type, const std::string &val,
                             bool invector, const FieldDef &afield) {
      switch (type.base_type) {
        case BASE_TYPE_STRING: {
          if (FlexibleStringConstructor(&afield)) {
            return NativeString(&afield) + "(" + val + "->c_str(), " + val +
                   "->size())";
          } else {
            return val + "->str()";
          }
        }
        case BASE_TYPE_STRUCT: {
          const auto name = WrapInNameSpace(*type.struct_def);
          if (IsStruct(type)) {
            auto native_type = type.struct_def->attributes.Lookup("native_type");
            if (native_type) {
              return "flatbuffers::UnPack(*" + val + ")";
            } else if (invector || afield.native_inline) {
              return "*" + val;
            } else {
              const auto ptype = GenTypeNativePtr(name, &afield, true);
              return ptype + "(new " + name + "(*" + val + "))";
            }
          } else {
            const auto ptype = GenTypeNativePtr(
                NativeName(name, type.struct_def, parser_.opts), &afield, true);
            return ptype + "(" + val + "->UnPack(_resolver))";
          }
        }
        case BASE_TYPE_UNION: {
          return GenUnionUnpackVal(
              afield, invector ? "->Get(_i)" : "",
              invector ? ("->GetEnum<" + type.enum_def->name + ">(_i)").c_str()
                       : "");
        }
        default: {
          return val;
          break;
        }
      }
    }
  
    std::string GenUnpackFieldStatement(const FieldDef &field,
                                        const FieldDef *union_field) {
      std::string code;
      switch (field.value.type.base_type) {
        case BASE_TYPE_VECTOR: {
          auto cpp_type = field.attributes.Lookup("cpp_type");
          std::string indexing;
          if (field.value.type.enum_def) {
            indexing += "static_cast<" +
                        WrapInNameSpace(*field.value.type.enum_def) + ">(";
          }
          indexing += "_e->Get(_i)";
          if (field.value.type.enum_def) { indexing += ")"; }
          if (field.value.type.element == BASE_TYPE_BOOL) { indexing += " != 0"; }
  
          // Generate code that pushes data from _e to _o in the form:
          //   for (uoffset_t i = 0; i < _e->size(); ++i) {
          //     _o->field.push_back(_e->Get(_i));
          //   }
          auto name = Name(field);
          if (field.value.type.element == BASE_TYPE_UTYPE) {
            name = StripUnionType(Name(field));
          }
          auto access =
              field.value.type.element == BASE_TYPE_UTYPE
                  ? ".type"
                  : (field.value.type.element == BASE_TYPE_UNION ? ".value" : "");
          code += "{ _o->" + name + ".resize(_e->size()); ";
          code += "for (flatbuffers::uoffset_t _i = 0;";
          code += " _i < _e->size(); _i++) { ";
          if (cpp_type) {
            // Generate code that resolves the cpp pointer type, of the form:
            //  if (resolver)
            //    (*resolver)(&_o->field, (hash_value_t)(_e));
            //  else
            //    _o->field = nullptr;
            code += "//vector resolver, " + PtrType(&field) + "\n";
            code += "if (_resolver) ";
            code += "(*_resolver)";
            code += "(reinterpret_cast<void **>(&_o->" + name + "[_i]" + access +
                    "), ";
            code += "static_cast<flatbuffers::hash_value_t>(" + indexing + "));";
            if (PtrType(&field) == "naked") {
              code += " else ";
              code += "_o->" + name + "[_i]" + access + " = nullptr";
            } else {
              // code += " else ";
              // code += "_o->" + name + "[_i]" + access + " = " +
              // GenTypeNativePtr(cpp_type->constant, &field, true) + "();";
              code += "/* else do nothing */";
            }
          } else {
            code += "_o->" + name + "[_i]" + access + " = ";
            code += GenUnpackVal(field.value.type.VectorType(), indexing, true,
                                 field);
          }
          code += "; } }";
          break;
        }
        case BASE_TYPE_UTYPE: {
          FLATBUFFERS_ASSERT(union_field->value.type.base_type ==
                             BASE_TYPE_UNION);
          // Generate code that sets the union type, of the form:
          //   _o->field.type = _e;
          code += "_o->" + union_field->name + ".type = _e;";
          break;
        }
        case BASE_TYPE_UNION: {
          // Generate code that sets the union value, of the form:
          //   _o->field.value = Union::Unpack(_e, field_type(), resolver);
          code += "_o->" + Name(field) + ".value = ";
          code += GenUnionUnpackVal(field, "", "");
          code += ";";
          break;
        }
        default: {
          auto cpp_type = field.attributes.Lookup("cpp_type");
          if (cpp_type) {
            // Generate code that resolves the cpp pointer type, of the form:
            //  if (resolver)
            //    (*resolver)(&_o->field, (hash_value_t)(_e));
            //  else
            //    _o->field = nullptr;
            code += "//scalar resolver, " + PtrType(&field) + " \n";
            code += "if (_resolver) ";
            code += "(*_resolver)";
            code += "(reinterpret_cast<void **>(&_o->" + Name(field) + "), ";
            code += "static_cast<flatbuffers::hash_value_t>(_e));";
            if (PtrType(&field) == "naked") {
              code += " else ";
              code += "_o->" + Name(field) + " = nullptr;";
            } else {
              // code += " else ";
              // code += "_o->" + Name(field) + " = " +
              // GenTypeNativePtr(cpp_type->constant, &field, true) + "();";
              code += "/* else do nothing */;";
            }
          } else {
            // Generate code for assigning the value, of the form:
            //  _o->field = value;
            code += "_o->" + Name(field) + " = ";
            code += GenUnpackVal(field.value.type, "_e", false, field) + ";";
          }
          break;
        }
      }
      return code;
    }
  
    std::string GenCreateParam(const FieldDef &field) {
      const IDLOptions &opts = parser_.opts;
  
      std::string value = "_o->";
      if (field.value.type.base_type == BASE_TYPE_UTYPE) {
        value += StripUnionType(Name(field));
        value += ".type";
      } else {
        value += Name(field);
      }
      if (field.value.type.base_type != BASE_TYPE_VECTOR &&
          field.attributes.Lookup("cpp_type")) {
        auto type = GenTypeBasic(field.value.type, false);
        value =
            "_rehasher ? "
            "static_cast<" +
            type + ">((*_rehasher)(" + value + GenPtrGet(field) + ")) : 0";
      }
  
      std::string code;
      switch (field.value.type.base_type) {
        // String fields are of the form:
        //   _fbb.CreateString(_o->field)
        // or
        //   _fbb.CreateSharedString(_o->field)
        case BASE_TYPE_STRING: {
          if (!field.shared) {
            code += "_fbb.CreateString(";
          } else {
            code += "_fbb.CreateSharedString(";
          }
          code += value;
          code.push_back(')');
  
          // For optional fields, check to see if there actually is any data
          // in _o->field before attempting to access it. If there isn't,
          // depending on set_empty_to_null either set it to 0 or an empty string.
          if (!field.required) {
            auto empty_value =
                opts.set_empty_to_null ? "0" : "_fbb.CreateSharedString(\"\")";
            code = value + ".empty() ? " + empty_value + " : " + code;
          }
          break;
        }
        // Vector fields come in several flavours, of the forms:
        //   _fbb.CreateVector(_o->field);
        //   _fbb.CreateVector((const utype*)_o->field.data(), _o->field.size());
        //   _fbb.CreateVectorOfStrings(_o->field)
        //   _fbb.CreateVectorOfStructs(_o->field)
        //   _fbb.CreateVector<Offset<T>>(_o->field.size() [&](size_t i) {
        //     return CreateT(_fbb, _o->Get(i), rehasher);
        //   });
        case BASE_TYPE_VECTOR: {
          auto vector_type = field.value.type.VectorType();
          switch (vector_type.base_type) {
            case BASE_TYPE_STRING: {
              if (NativeString(&field) == "std::string") {
                code += "_fbb.CreateVectorOfStrings(" + value + ")";
              } else {
                // Use by-function serialization to emulate
                // CreateVectorOfStrings(); this works also with non-std strings.
                code +=
                    "_fbb.CreateVector<flatbuffers::Offset<flatbuffers::String>>"
                    " ";
                code += "(" + value + ".size(), ";
                code += "[](size_t i, _VectorArgs *__va) { ";
                code +=
                    "return __va->__fbb->CreateString(__va->_" + value + "[i]);";
                code += " }, &_va )";
              }
              break;
            }
            case BASE_TYPE_STRUCT: {
              if (IsStruct(vector_type)) {
                auto native_type =
                    field.value.type.struct_def->attributes.Lookup("native_type");
                if (native_type) {
                  code += "_fbb.CreateVectorOfNativeStructs<";
                  code += WrapInNameSpace(*vector_type.struct_def) + ">";
                } else {
                  code += "_fbb.CreateVectorOfStructs";
                }
                code += "(" + value + ")";
              } else {
                code += "_fbb.CreateVector<flatbuffers::Offset<";
                code += WrapInNameSpace(*vector_type.struct_def) + ">> ";
                code += "(" + value + ".size(), ";
                code += "[](size_t i, _VectorArgs *__va) { ";
                code += "return Create" + vector_type.struct_def->name;
                code += "(*__va->__fbb, __va->_" + value + "[i]" +
                        GenPtrGet(field) + ", ";
                code += "__va->__rehasher); }, &_va )";
              }
              break;
            }
            case BASE_TYPE_BOOL: {
              code += "_fbb.CreateVector(" + value + ")";
              break;
            }
            case BASE_TYPE_UNION: {
              code +=
                  "_fbb.CreateVector<flatbuffers::"
                  "Offset<void>>(" +
                  value +
                  ".size(), [](size_t i, _VectorArgs *__va) { "
                  "return __va->_" +
                  value + "[i].Pack(*__va->__fbb, __va->__rehasher); }, &_va)";
              break;
            }
            case BASE_TYPE_UTYPE: {
              value = StripUnionType(value);
              code += "_fbb.CreateVector<uint8_t>(" + value +
                      ".size(), [](size_t i, _VectorArgs *__va) { "
                      "return static_cast<uint8_t>(__va->_" +
                      value + "[i].type); }, &_va)";
              break;
            }
            default: {
              if (field.value.type.enum_def) {
                // For enumerations, we need to get access to the array data for
                // the underlying storage type (eg. uint8_t).
                const auto basetype = GenTypeBasic(
                    field.value.type.enum_def->underlying_type, false);
                code += "_fbb.CreateVectorScalarCast<" + basetype +
                        ">(flatbuffers::data(" + value + "), " + value +
                        ".size())";
              } else if (field.attributes.Lookup("cpp_type")) {
                auto type = GenTypeBasic(vector_type, false);
                code += "_fbb.CreateVector<" + type + ">(" + value + ".size(), ";
                code += "[](size_t i, _VectorArgs *__va) { ";
                code += "return __va->__rehasher ? ";
                code += "static_cast<" + type + ">((*__va->__rehasher)";
                code += "(__va->_" + value + "[i]" + GenPtrGet(field) + ")) : 0";
                code += "; }, &_va )";
              } else {
                code += "_fbb.CreateVector(" + value + ")";
              }
              break;
            }
          }
  
          // If set_empty_to_null option is enabled, for optional fields, check to
          // see if there actually is any data in _o->field before attempting to
          // access it.
          if (opts.set_empty_to_null && !field.required) {
            code = value + ".size() ? " + code + " : 0";
          }
          break;
        }
        case BASE_TYPE_UNION: {
          // _o->field.Pack(_fbb);
          code += value + ".Pack(_fbb)";
          break;
        }
        case BASE_TYPE_STRUCT: {
          if (IsStruct(field.value.type)) {
            auto native_type =
                field.value.type.struct_def->attributes.Lookup("native_type");
            if (native_type) {
              code += "flatbuffers::Pack(" + value + ")";
            } else if (field.native_inline) {
              code += "&" + value;
            } else {
              code += value + " ? " + value + GenPtrGet(field) + " : 0";
            }
          } else {
            // _o->field ? CreateT(_fbb, _o->field.get(), _rehasher);
            const auto type = field.value.type.struct_def->name;
            code += value + " ? Create" + type;
            code += "(_fbb, " + value + GenPtrGet(field) + ", _rehasher)";
            code += " : 0";
          }
          break;
        }
        default: {
          code += value;
          break;
        }
      }
      return code;
    }
  
    // Generate code for tables that needs to come after the regular definition.
    void GenTablePost(const StructDef &struct_def) {
      code_.SetValue("STRUCT_NAME", Name(struct_def));
      code_.SetValue("NATIVE_NAME",
                     NativeName(Name(struct_def), &struct_def, parser_.opts));
  
      if (parser_.opts.generate_object_based_api) {
        // Generate the X::UnPack() method.
        code_ += "inline " +
                 TableUnPackSignature(struct_def, false, parser_.opts) + " {";
        code_ += "  auto _o = new {{NATIVE_NAME}}();";
        code_ += "  UnPackTo(_o, _resolver);";
        code_ += "  return _o;";
        code_ += "}";
        code_ += "";
  
        code_ += "inline " +
                 TableUnPackToSignature(struct_def, false, parser_.opts) + " {";
        code_ += "  (void)_o;";
        code_ += "  (void)_resolver;";
  
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (field.deprecated) { continue; }
  
          // Assign a value from |this| to |_o|.   Values from |this| are stored
          // in a variable |_e| by calling this->field_type().  The value is then
          // assigned to |_o| using the GenUnpackFieldStatement.
          const bool is_union = field.value.type.base_type == BASE_TYPE_UTYPE;
          const auto statement =
              GenUnpackFieldStatement(field, is_union ? *(it + 1) : nullptr);
  
          code_.SetValue("FIELD_NAME", Name(field));
          auto prefix = "  { auto _e = {{FIELD_NAME}}(); ";
          auto check = IsScalar(field.value.type.base_type) ? "" : "if (_e) ";
          auto postfix = " };";
          code_ += std::string(prefix) + check + statement + postfix;
        }
        code_ += "}";
        code_ += "";
  
        // Generate the X::Pack member function that simply calls the global
        // CreateX function.
        code_ += "inline " + TablePackSignature(struct_def, false, parser_.opts) +
                 " {";
        code_ += "  return Create{{STRUCT_NAME}}(_fbb, _o, _rehasher);";
        code_ += "}";
        code_ += "";
  
        // Generate a CreateX method that works with an unpacked C++ object.
        code_ += "inline " +
                 TableCreateSignature(struct_def, false, parser_.opts) + " {";
        code_ += "  (void)_rehasher;";
        code_ += "  (void)_o;";
  
        code_ +=
            "  struct _VectorArgs "
            "{ flatbuffers::FlatBufferBuilder *__fbb; "
            "const " +
            NativeName(Name(struct_def), &struct_def, parser_.opts) +
            "* __o; "
            "const flatbuffers::rehasher_function_t *__rehasher; } _va = { "
            "&_fbb, _o, _rehasher}; (void)_va;";
  
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          auto &field = **it;
          if (field.deprecated) { continue; }
          code_ += "  auto _" + Name(field) + " = " + GenCreateParam(field) + ";";
        }
        // Need to call "Create" with the struct namespace.
        const auto qualified_create_name =
            struct_def.defined_namespace->GetFullyQualifiedName("Create");
        code_.SetValue("CREATE_NAME", TranslateNameSpace(qualified_create_name));
  
        code_ += "  return {{CREATE_NAME}}{{STRUCT_NAME}}(";
        code_ += "      _fbb\\";
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          auto &field = **it;
          if (field.deprecated) { continue; }
  
          bool pass_by_address = false;
          if (field.value.type.base_type == BASE_TYPE_STRUCT) {
            if (IsStruct(field.value.type)) {
              auto native_type =
                  field.value.type.struct_def->attributes.Lookup("native_type");
              if (native_type) { pass_by_address = true; }
            }
          }
  
          // Call the CreateX function using values from |_o|.
          if (pass_by_address) {
            code_ += ",\n      &_" + Name(field) + "\\";
          } else {
            code_ += ",\n      _" + Name(field) + "\\";
          }
        }
        code_ += ");";
        code_ += "}";
        code_ += "";
      }
    }
  
    static void GenPadding(
        const FieldDef &field, std::string *code_ptr, int *id,
        const std::function<void(int bits, std::string *code_ptr, int *id)> &f) {
      if (field.padding) {
        for (int i = 0; i < 4; i++) {
          if (static_cast<int>(field.padding) & (1 << i)) {
            f((1 << i) * 8, code_ptr, id);
          }
        }
        FLATBUFFERS_ASSERT(!(field.padding & ~0xF));
      }
    }
  
    static void PaddingDefinition(int bits, std::string *code_ptr, int *id) {
      *code_ptr += "  int" + NumToString(bits) + "_t padding" +
                   NumToString((*id)++) + "__;";
    }
  
    static void PaddingInitializer(int bits, std::string *code_ptr, int *id) {
      (void)bits;
      *code_ptr += ",\n        padding" + NumToString((*id)++) + "__(0)";
    }
  
    static void PaddingNoop(int bits, std::string *code_ptr, int *id) {
      (void)bits;
      *code_ptr += "    (void)padding" + NumToString((*id)++) + "__;";
    }
  
    // Generate an accessor struct with constructor for a flatbuffers struct.
    void GenStruct(const StructDef &struct_def) {
      // Generate an accessor struct, with private variables of the form:
      // type name_;
      // Generates manual padding and alignment.
      // Variables are private because they contain little endian data on all
      // platforms.
      GenComment(struct_def.doc_comment);
      code_.SetValue("ALIGN", NumToString(struct_def.minalign));
      code_.SetValue("STRUCT_NAME", Name(struct_def));
  
      code_ +=
          "FLATBUFFERS_MANUALLY_ALIGNED_STRUCT({{ALIGN}}) "
          "{{STRUCT_NAME}} FLATBUFFERS_FINAL_CLASS {";
      code_ += " private:";
  
      int padding_id = 0;
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        code_.SetValue("FIELD_TYPE",
                       GenTypeGet(field.value.type, " ", "", " ", false));
        code_.SetValue("FIELD_NAME", Name(field));
        code_ += "  {{FIELD_TYPE}}{{FIELD_NAME}}_;";
  
        if (field.padding) {
          std::string padding;
          GenPadding(field, &padding, &padding_id, PaddingDefinition);
          code_ += padding;
        }
      }
  
      // Generate GetFullyQualifiedName
      code_ += "";
      code_ += " public:";
  
      // Make TypeTable accessible via the generated struct.
      if (parser_.opts.mini_reflect != IDLOptions::kNone) {
        code_ +=
            "  static const flatbuffers::TypeTable *MiniReflectTypeTable() {";
        code_ += "    return {{STRUCT_NAME}}TypeTable();";
        code_ += "  }";
      }
  
      GenFullyQualifiedNameGetter(struct_def, Name(struct_def));
  
      // Generate a default constructor.
      code_ += "  {{STRUCT_NAME}}() {";
      code_ += "    memset(static_cast<void *>(this), 0, sizeof({{STRUCT_NAME}}));";
      code_ += "  }";
  
      // Generate a constructor that takes all fields as arguments.
      std::string arg_list;
      std::string init_list;
      padding_id = 0;
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
        const auto member_name = Name(field) + "_";
        const auto arg_name = "_" + Name(field);
        const auto arg_type =
            GenTypeGet(field.value.type, " ", "const ", " &", true);
  
        if (it != struct_def.fields.vec.begin()) {
          arg_list += ", ";
          init_list += ",\n        ";
        }
        arg_list += arg_type;
        arg_list += arg_name;
        init_list += member_name;
        if (IsScalar(field.value.type.base_type)) {
          auto type = GenUnderlyingCast(field, false, arg_name);
          init_list += "(flatbuffers::EndianScalar(" + type + "))";
        } else {
          init_list += "(" + arg_name + ")";
        }
        if (field.padding) {
          GenPadding(field, &init_list, &padding_id, PaddingInitializer);
        }
      }
  
      if (!arg_list.empty()) {
        code_.SetValue("ARG_LIST", arg_list);
        code_.SetValue("INIT_LIST", init_list);
        code_ += "  {{STRUCT_NAME}}({{ARG_LIST}})";
        code_ += "      : {{INIT_LIST}} {";
        padding_id = 0;
        for (auto it = struct_def.fields.vec.begin();
             it != struct_def.fields.vec.end(); ++it) {
          const auto &field = **it;
          if (field.padding) {
            std::string padding;
            GenPadding(field, &padding, &padding_id, PaddingNoop);
            code_ += padding;
          }
        }
        code_ += "  }";
      }
  
      // Generate accessor methods of the form:
      // type name() const { return flatbuffers::EndianScalar(name_); }
      for (auto it = struct_def.fields.vec.begin();
           it != struct_def.fields.vec.end(); ++it) {
        const auto &field = **it;
  
        auto field_type = GenTypeGet(field.value.type, " ", "const ", " &", true);
        auto is_scalar = IsScalar(field.value.type.base_type);
        auto member = Name(field) + "_";
        auto value =
            is_scalar ? "flatbuffers::EndianScalar(" + member + ")" : member;
  
        code_.SetValue("FIELD_NAME", Name(field));
        code_.SetValue("FIELD_TYPE", field_type);
        code_.SetValue("FIELD_VALUE", GenUnderlyingCast(field, true, value));
  
        GenComment(field.doc_comment, "  ");
        code_ += "  {{FIELD_TYPE}}{{FIELD_NAME}}() const {";
        code_ += "    return {{FIELD_VALUE}};";
        code_ += "  }";
  
        if (parser_.opts.mutable_buffer) {
          auto mut_field_type = GenTypeGet(field.value.type, " ", "", " &", true);
          code_.SetValue("FIELD_TYPE", mut_field_type);
          if (is_scalar) {
            code_.SetValue("ARG", GenTypeBasic(field.value.type, true));
            code_.SetValue("FIELD_VALUE",
                           GenUnderlyingCast(field, false, "_" + Name(field)));
  
            code_ += "  void mutate_{{FIELD_NAME}}({{ARG}} _{{FIELD_NAME}}) {";
            code_ +=
                "    flatbuffers::WriteScalar(&{{FIELD_NAME}}_, "
                "{{FIELD_VALUE}});";
            code_ += "  }";
          } else {
            code_ += "  {{FIELD_TYPE}}mutable_{{FIELD_NAME}}() {";
            code_ += "    return {{FIELD_NAME}}_;";
            code_ += "  }";
          }
        }
  
        // Generate a comparison function for this field if it is a key.
        if (field.key) { GenKeyFieldMethods(field); }
      }
      code_.SetValue("NATIVE_NAME", Name(struct_def));
      GenOperatorNewDelete(struct_def);
      code_ += "};";
  
      code_.SetValue("STRUCT_BYTE_SIZE", NumToString(struct_def.bytesize));
      code_ += "FLATBUFFERS_STRUCT_END({{STRUCT_NAME}}, {{STRUCT_BYTE_SIZE}});";
      if (parser_.opts.gen_compare) GenCompareOperator(struct_def, "()");
      code_ += "";
    }
  
    // Set up the correct namespace. Only open a namespace if the existing one is
    // different (closing/opening only what is necessary).
    //
    // The file must start and end with an empty (or null) namespace so that
    // namespaces are properly opened and closed.
    void SetNameSpace(const Namespace *ns) {
      if (cur_name_space_ == ns) { return; }
  
      // Compute the size of the longest common namespace prefix.
      // If cur_name_space is A::B::C::D and ns is A::B::E::F::G,
      // the common prefix is A::B:: and we have old_size = 4, new_size = 5
      // and common_prefix_size = 2
      size_t old_size = cur_name_space_ ? cur_name_space_->components.size() : 0;
      size_t new_size = ns ? ns->components.size() : 0;
  
      size_t common_prefix_size = 0;
      while (common_prefix_size < old_size && common_prefix_size < new_size &&
             ns->components[common_prefix_size] ==
                 cur_name_space_->components[common_prefix_size]) {
        common_prefix_size++;
      }
  
      // Close cur_name_space in reverse order to reach the common prefix.
      // In the previous example, D then C are closed.
      for (size_t j = old_size; j > common_prefix_size; --j) {
        code_ += "}  // namespace " + cur_name_space_->components[j - 1];
      }
      if (old_size != common_prefix_size) { code_ += ""; }
  
      // open namespace parts to reach the ns namespace
      // in the previous example, E, then F, then G are opened
      for (auto j = common_prefix_size; j != new_size; ++j) {
        code_ += "namespace " + ns->components[j] + " {";
      }
      if (new_size != common_prefix_size) { code_ += ""; }
  
      cur_name_space_ = ns;
    }
  
    const TypedFloatConstantGenerator float_const_gen_;
  };
  
  }  // namespace cpp
  
  bool GenerateCPP(const Parser &parser, const std::string &path,
                   const std::string &file_name) {
    cpp::CppGenerator generator(parser, path, file_name);
    return generator.generate();
  }
  
  std::string CPPMakeRule(const Parser &parser, const std::string &path,
                          const std::string &file_name) {
    const auto filebase =
        flatbuffers::StripPath(flatbuffers::StripExtension(file_name));
    const auto included_files = parser.GetIncludedFilesRecursive(file_name);
    std::string make_rule = GeneratedFileName(path, filebase) + ": ";
    for (auto it = included_files.begin(); it != included_files.end(); ++it) {
      make_rule += " " + *it;
    }
    return make_rule;
  }
  
  }  // namespace flatbuffers
  