Compile-Time Map - Static Hash Map at Compile Time

Allows to have a hash map built at compile time. The map could be used to perform runtime as well as compile-time lookups.

Install

• C++-14 supporting compiler
• Header-only usage without any external dependencies, except the Standard Library.

Usage

More examples could be found in tests/tests.cpp.

class JsonSerializable {
public:
  virtual ~JsonSerializable() {}

  static JsonSerializable* createFromJson(JsonObject const& json_object);
};

class Holy : public JsonSerializable {
public:
  static JsonSerializable* createFromJson(JsonObject const& json_object) {
    auto holy = new Holy;
    // Fill `holy` with data from `json_object`
    return holy;
  }
};
class Moly : public JsonSerializable {
public:
  static JsonSerializable* createFromJson(JsonObject const& json_object) {
    auto moly = new Moly;
    // Fill `moly` with data from `json_object`
    return moly;
  }
};
class Miny : public JsonSerializable {
public:
  static JsonSerializable* createFromJson(JsonObject const& json_object) {
    auto miny = new Miny;
    // Fill `miny` with data from `json_object`
    return miny;
  }
};
class Moe : public JsonSerializable {
public:
  static JsonSerializable* createFromJson(JsonObject const& json_object) {
    auto moe = new Moe;
    // Fill `moe` with data from `json_object`
    return moe;
  }
};

JsonSerializable* JsonSerializable::createFromJson(JsonObject const& json_object) {
  constexpr auto spec = ctm::makeHashMapSpec(std::make_tuple("Holy", &Holy::createFromJson),
                                             std::make_tuple("Moly", &Moly::createFromJson),
                                             std::make_tuple("Miny", &Miny::createFromJson),
                                             std::make_tuple("Moe", &Moe::createFromJson));
  static constexpr auto map = ctm::HashMap<decltype(spec),
                                           spec.maxBucketSize,
                                           spec.bucketCount,
                                           spec.elementCount>::make(spec);
  auto factory_function = map[json_object.at("type")];
  if (factory_function == nullptr)
    return nullptr;
  return factory_function(json_object);
}