#ifndef EXTERNAL_VALUE_H
#define EXTERNAL_VALUE_H

#include "ruby/config.h"

#if defined(__DOXYGEN__)

/**
 * Type that represents a Ruby object.  It is an unsigned integer of some kind,
 * depending on platforms.
 *
 * ```CXX
 * VALUE value = rb_eval_string("ARGF.readlines.map.with_index");
 * ```
 *
 * @warning  ::VALUE is not a pointer.
 * @warning  ::VALUE can be wider than `long`.
 */
typedef uintptr_t VALUE;

/**
 * Type that represents a Ruby identifier such as a variable name.
 *
 * ```CXX
 * ID method = rb_intern("method");
 * VALUE result = rb_funcall(obj, method, 0);
 * ```
 *
 * @note  ::rb_cSymbol is a Ruby-level data type for the same thing.
 */
typedef uintptr_t ID;

/**
 * A signed integer type that has the same width with ::VALUE.
 *
 * @internal
 *
 * @shyouhei wonders: is it guaranteed  that `uintptr_t` and `intptr_t` are the
 * same width?  As far as I read ISO/IEC 9899:2018 section 7.20.1.4 paragraph 1
 * no such description is given... or defined elsewhere?
 */
typedef intptr_t SIGNED_VALUE;

/**
 * Identical to  `sizeof(VALUE)`, except it  is a macro  that can also  be used
 * inside of preprocessor directives such as `#if`.  Handy on occasions.
 */
#define SIZEOF_VALUE SIZEOF_UINTPTR_T

/**
 * @private
 *
 * A compile-time constant of type ::VALUE whose value is 0.
 */
#define RBIMPL_VALUE_NULL UINTPTR_C(0)

/**
 * @private
 *
 * A compile-time constant of type ::VALUE whose value is 1.
 */
#define RBIMPL_VALUE_ONE  UINTPTR_C(1)

/**
 * @private
 *
 * Maximum possible value that a ::VALUE can take.
 */
#define RBIMPL_VALUE_FULL UINTPTR_MAX

#elif defined HAVE_UINTPTR_T && 0
typedef uintptr_t VALUE;
typedef uintptr_t ID;
# define SIGNED_VALUE intptr_t
# define SIZEOF_VALUE SIZEOF_UINTPTR_T
# undef PRI_VALUE_PREFIX
# define RBIMPL_VALUE_NULL UINTPTR_C(0)
# define RBIMPL_VALUE_ONE  UINTPTR_C(1)
# define RBIMPL_VALUE_FULL UINTPTR_MAX

#elif SIZEOF_LONG == SIZEOF_VOIDP
typedef unsigned long VALUE;
typedef unsigned long ID;
# define SIGNED_VALUE long
# define SIZEOF_VALUE SIZEOF_LONG
# define PRI_VALUE_PREFIX "l"
# define RBIMPL_VALUE_NULL 0UL
# define RBIMPL_VALUE_ONE  1UL
# define RBIMPL_VALUE_FULL ULONG_MAX

#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
typedef unsigned LONG_LONG VALUE;
typedef unsigned LONG_LONG ID;
# define SIGNED_VALUE LONG_LONG
# define LONG_LONG_VALUE 1
# define SIZEOF_VALUE SIZEOF_LONG_LONG
# define PRI_VALUE_PREFIX PRI_LL_PREFIX
# define RBIMPL_VALUE_NULL 0ULL
# define RBIMPL_VALUE_ONE  1ULL
# define RBIMPL_VALUE_FULL ULLONG_MAX

#else
# error ---->> ruby requires sizeof(void*) == sizeof(long) or sizeof(LONG_LONG) to be compiled. <<----
#endif

#endif /* EXTERNAL_VALUE_H */