meta_c.h

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/**
 * @file addons/meta_c.h
 * @brief Utility macros for populating reflection data in C.
 */
 
#ifdef FLECS_META
 
/**
 * @defgroup c_addons_meta_c Meta Utilities
 * @ingroup c_addons
 * Macro utilities to automatically insert reflection data.
 *
 * @{
 */
 
#ifndef FLECS_META_C_H
#define FLECS_META_C_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* Macro that controls behavior of API. Usually set in module header. When the
 * macro is not defined, it defaults to IMPL. */
 
/* Define variables used by reflection utilities. This should only be defined
 * by the module itself, not by the code importing the module. */
/* #define ECS_META_IMPL IMPL */
 
/* Don't define variables used by reflection utilities, but still declare the
 * variable for the component ID. This enables the reflection utilities to be
 * used for global component variables, even if no reflection is used. */
/* #define ECS_META_IMPL DECLARE */
 
/* Don't define variables used by reflection utilities. This generates an extern
 * variable for the component identifier. */
/* #define ECS_META_IMPL EXTERN */
 
/** Declare component with descriptor. */
#define ECS_META_COMPONENT(world, name)\
    ECS_COMPONENT_DEFINE(world, name);\
    ecs_meta_from_desc(world, ecs_id(name),\
        FLECS__##name##_kind, FLECS__##name##_desc)
 
/** ECS_STRUCT(name, body). */
#define ECS_STRUCT(name, ...)\
    ECS_META_IMPL_CALL(ECS_STRUCT_, ECS_META_IMPL, name, #__VA_ARGS__);\
    ECS_STRUCT_TYPE(name, __VA_ARGS__)
 
/** ECS_ENUM(name, body). */
#define ECS_ENUM(name, ...)\
    ECS_META_IMPL_CALL(ECS_ENUM_, ECS_META_IMPL, name, #__VA_ARGS__);\
    ECS_ENUM_TYPE(name, __VA_ARGS__)
 
/** ECS_BITMASK(name, body). */
#define ECS_BITMASK(name, ...)\
    ECS_META_IMPL_CALL(ECS_BITMASK_, ECS_META_IMPL, name, #__VA_ARGS__);\
    ECS_ENUM_TYPE(name, __VA_ARGS__)
 
/** Macro used to mark part of type for which no reflection data is created. */
#define ECS_PRIVATE
 
/** Macro used to declare a vector member in types with reflection data. */
#define ecs_vec(T) ecs_vec_t
 
/** Macro used to declare a map member in types with reflection data. */
#define ecs_map(K, V) ecs_map_t
 
/** Populate meta information from type descriptor. */
FLECS_API
int ecs_meta_from_desc(
    ecs_world_t *world,
    ecs_entity_t component,
    ecs_type_kind_t kind,
    const char *desc);
 
 
/** \cond
 * Private utilities to switch between meta IMPL, DECLARE and EXTERN variants.
 */
 
#define ECS_META_IMPL_CALL_INNER(base, impl, name, type_desc)\
    base ## impl(name, type_desc)
 
#define ECS_META_IMPL_CALL(base, impl, name, type_desc)\
    ECS_META_IMPL_CALL_INNER(base, impl, name, type_desc)
 
/* ECS_STRUCT implementation */
#define ECS_STRUCT_TYPE(name, ...)\
    typedef struct name __VA_ARGS__ name
 
#define ECS_STRUCT_ECS_META_IMPL ECS_STRUCT_IMPL
 
#define ECS_STRUCT_IMPL(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    static const char *FLECS__##name##_desc = type_desc;\
    static ecs_type_kind_t FLECS__##name##_kind = EcsStructType;\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_STRUCT_DECLARE(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_STRUCT_EXTERN(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name)
 
 
/* ECS_ENUM implementation */
#define ECS_ENUM_TYPE(name, ...)\
    typedef enum name __VA_ARGS__ name
 
#define ECS_ENUM_ECS_META_IMPL ECS_ENUM_IMPL
 
#define ECS_ENUM_IMPL(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    static const char *FLECS__##name##_desc = type_desc;\
    static ecs_type_kind_t FLECS__##name##_kind = EcsEnumType;\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_ENUM_DECLARE(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_ENUM_EXTERN(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name)
 
 
/* ECS_BITMASK implementation */
#define ECS_BITMASK_TYPE(name, ...)\
    typedef enum name __VA_ARGS__ name
 
#define ECS_BITMASK_ECS_META_IMPL ECS_BITMASK_IMPL
 
#define ECS_BITMASK_IMPL(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    static const char *FLECS__##name##_desc = type_desc;\
    static ecs_type_kind_t FLECS__##name##_kind = EcsBitmaskType;\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_BITMASK_DECLARE(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name);\
    ECS_COMPONENT_DECLARE(name) = 0
 
#define ECS_BITMASK_EXTERN(name, type_desc)\
    extern ECS_COMPONENT_DECLARE(name)
 
/** \endcond */
 
#ifdef __cplusplus
}
#endif
 
#ifdef __cplusplus
 
#undef ECS_STRUCT
#define ECS_STRUCT(name, ...)\
    struct name __VA_ARGS__;\
    inline const char* flecs_meta_cpp_desc(name*) { return #__VA_ARGS__; }\
    inline ecs_type_kind_t flecs_meta_cpp_kind(name*) { return EcsStructType; }\
    static_assert(true, "")
 
#undef ECS_ENUM
#define ECS_ENUM(name, ...)\
    enum name __VA_ARGS__;\
    inline const char* flecs_meta_cpp_desc(name*) { return #__VA_ARGS__; }\
    inline ecs_type_kind_t flecs_meta_cpp_kind(name*) { return EcsEnumType; }\
    static_assert(true, "")
 
#undef ECS_BITMASK
#define ECS_BITMASK(name, ...)\
    enum name __VA_ARGS__;\
    inline const char* flecs_meta_cpp_desc(name*) { return #__VA_ARGS__; }\
    inline ecs_type_kind_t flecs_meta_cpp_kind(name*) { return EcsBitmaskType; }\
    static_assert(true, "")
 
#endif
 
#endif // FLECS_META_C_H
 
/** @} */
 
#endif // FLECS_META