#ifndef RBIMPL_SPECIAL_CONSTS_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_SPECIAL_CONSTS_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Defines enum ::ruby_special_consts.
* @see Sasada, K., "A Lightweight Representation of Floating-Point
* Numbers on Ruby Interpreter", in proceedings of 10th JSSST
* SIGPPL Workshop on Programming and Programming Languages
* (PPL2008), pp. 9-16, 2008.
*/
#include "ruby/internal/attr/artificial.h"
#include "ruby/internal/attr/const.h"
#include "ruby/internal/attr/constexpr.h"
#include "ruby/internal/attr/enum_extensibility.h"
#include "ruby/internal/stdbool.h"
#include "ruby/internal/value.h"
/**
* @private
* @warning Do not touch this macro.
* @warning It is an implementation detail.
* @warning The value of this macro must match for ruby itself and all
* extension libraries, otherwise serious memory corruption shall
* occur.
*/
#if defined(USE_FLONUM)
# /* Take that. */
#elif SIZEOF_VALUE >= SIZEOF_DOUBLE
# define USE_FLONUM 1
#else
# define USE_FLONUM 0
#endif
/** This is an old name of #RB_TEST. Not sure which name is preferred. */
#define RTEST RB_TEST
#define FIXNUM_P RB_FIXNUM_P /**< @old{RB_FIXNUM_P} */
#define IMMEDIATE_P RB_IMMEDIATE_P /**< @old{RB_IMMEDIATE_P} */
#define NIL_P RB_NIL_P /**< @old{RB_NIL_P} */
#define SPECIAL_CONST_P RB_SPECIAL_CONST_P /**< @old{RB_SPECIAL_CONST_P} */
#define STATIC_SYM_P RB_STATIC_SYM_P /**< @old{RB_STATIC_SYM_P} */
#define Qfalse RUBY_Qfalse /**< @old{RUBY_Qfalse} */
#define Qnil RUBY_Qnil /**< @old{RUBY_Qnil} */
#define Qtrue RUBY_Qtrue /**< @old{RUBY_Qtrue} */
#define Qundef RUBY_Qundef /**< @old{RUBY_Qundef} */
#define FIXNUM_FLAG RUBY_FIXNUM_FLAG /**< @old{RUBY_FIXNUM_FLAG} */
#define FLONUM_FLAG RUBY_FLONUM_FLAG /**< @old{RUBY_FLONUM_FLAG} */
#define FLONUM_MASK RUBY_FLONUM_MASK /**< @old{RUBY_FLONUM_MASK} */
#define FLONUM_P RB_FLONUM_P /**< @old{RB_FLONUM_P} */
#define IMMEDIATE_MASK RUBY_IMMEDIATE_MASK /**< @old{RUBY_IMMEDIATE_MASK} */
#define SYMBOL_FLAG RUBY_SYMBOL_FLAG /**< @old{RUBY_SYMBOL_FLAG} */
/** @cond INTERNAL_MACRO */
#define RB_FIXNUM_P RB_FIXNUM_P
#define RB_FLONUM_P RB_FLONUM_P
#define RB_IMMEDIATE_P RB_IMMEDIATE_P
#define RB_NIL_P RB_NIL_P
#define RB_SPECIAL_CONST_P RB_SPECIAL_CONST_P
#define RB_STATIC_SYM_P RB_STATIC_SYM_P
#define RB_TEST RB_TEST
/** @endcond */
/** special constants - i.e. non-zero and non-fixnum constants */
enum
RBIMPL_ATTR_ENUM_EXTENSIBILITY(closed)
ruby_special_consts {
#if defined(__DOXYGEN__)
RUBY_Qfalse, /**< @see ::rb_cFalseClass */
RUBY_Qtrue, /**< @see ::rb_cTrueClass */
RUBY_Qnil, /**< @see ::rb_cNilClass */
RUBY_Qundef, /**< Represents so-called undef. */
RUBY_IMMEDIATE_MASK, /**< Bit mask detecting special consts. */
RUBY_FIXNUM_FLAG, /**< Flag to denote a fixnum. */
RUBY_FLONUM_MASK, /**< Bit mask detecting a flonum. */
RUBY_FLONUM_FLAG, /**< Flag to denote a flonum. */
RUBY_SYMBOL_FLAG, /**< Flag to denote a static symbol. */
#elif USE_FLONUM
RUBY_Qfalse = 0x00, /* ...0000 0000 */
RUBY_Qtrue = 0x14, /* ...0001 0100 */
RUBY_Qnil = 0x08, /* ...0000 1000 */
RUBY_Qundef = 0x34, /* ...0011 0100 */
RUBY_IMMEDIATE_MASK = 0x07, /* ...0000 0111 */
RUBY_FIXNUM_FLAG = 0x01, /* ...xxxx xxx1 */
RUBY_FLONUM_MASK = 0x03, /* ...0000 0011 */
RUBY_FLONUM_FLAG = 0x02, /* ...xxxx xx10 */
RUBY_SYMBOL_FLAG = 0x0c, /* ...xxxx 1100 */
#else
RUBY_Qfalse = 0x00, /* ...0000 0000 */
RUBY_Qtrue = 0x02, /* ...0000 0010 */
RUBY_Qnil = 0x04, /* ...0000 0100 */
RUBY_Qundef = 0x06, /* ...0000 0110 */
RUBY_IMMEDIATE_MASK = 0x03, /* ...0000 0011 */
RUBY_FIXNUM_FLAG = 0x01, /* ...xxxx xxx1 */
RUBY_FLONUM_MASK = 0x00, /* any values ANDed with FLONUM_MASK cannot be FLONUM_FLAG */
RUBY_FLONUM_FLAG = 0x02, /* ...0000 0010 */
RUBY_SYMBOL_FLAG = 0x0e, /* ...0000 1110 */
#endif
RUBY_SPECIAL_SHIFT = 8 /**< Least significant 8 bits are reserved. */
};
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Emulates Ruby's "if" statement.
*
* @param[in] obj An arbitrary ruby object.
* @retval false `obj` is either ::RUBY_Qfalse or ::RUBY_Qnil.
* @retval true Anything else.
*
* @internal
*
* It HAS to be `__attribute__((const))` in order for clang to properly deduce
* `__builtin_assume()`.
*/
static inline bool
RB_TEST(VALUE obj)
{
/*
* Qfalse: ....0000 0000
* Qnil: ....0000 1000
* ~Qnil: ....1111 0111
* v ....xxxx xxxx
* ----------------------------
* RTEST(v) ....xxxx 0xxx
*
* RTEST(v) can be 0 if and only if (v == Qfalse || v == Qnil).
*/
return obj & ~RUBY_Qnil;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is nil.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is ::RUBY_Qnil.
* @retval false Anything else.
*/
static inline bool
RB_NIL_P(VALUE obj)
{
return obj == RUBY_Qnil;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is a so-called Fixnum.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is a Fixnum.
* @retval false Anything else.
* @note Fixnum was a thing in the 20th century, but it is rather an
* implementation detail today.
*/
static inline bool
RB_FIXNUM_P(VALUE obj)
{
return obj & RUBY_FIXNUM_FLAG;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX14)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is a static symbol.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is a static symbol
* @retval false Anything else.
* @see RB_DYNAMIC_SYM_P()
* @see RB_SYMBOL_P()
* @note These days there are static and dynamic symbols, just like we
* once had Fixnum/Bignum back in the old days.
*/
static inline bool
RB_STATIC_SYM_P(VALUE obj)
{
RBIMPL_ATTR_CONSTEXPR(CXX14)
const VALUE mask = ~(RBIMPL_VALUE_FULL << RUBY_SPECIAL_SHIFT);
return (obj & mask) == RUBY_SYMBOL_FLAG;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is a so-called Flonum.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is a Flonum.
* @retval false Anything else.
* @see RB_FLOAT_TYPE_P()
* @note These days there are Flonums and non-Flonum floats, just like we
* once had Fixnum/Bignum back in the old days.
*/
static inline bool
RB_FLONUM_P(VALUE obj)
{
#if USE_FLONUM
return (obj & RUBY_FLONUM_MASK) == RUBY_FLONUM_FLAG;
#else
return false;
#endif
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is an immediate i.e. an object which has no
* corresponding storage inside of the object space.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is a Flonum.
* @retval false Anything else.
* @see RB_FLOAT_TYPE_P()
* @note The concept of "immediate" is purely C specific.
*/
static inline bool
RB_IMMEDIATE_P(VALUE obj)
{
return obj & RUBY_IMMEDIATE_MASK;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
RBIMPL_ATTR_ARTIFICIAL()
/**
* Checks if the given object is of enum ::ruby_special_consts.
*
* @param[in] obj An arbitrary ruby object.
* @retval true `obj` is a special constant.
* @retval false Anything else.
*/
static inline bool
RB_SPECIAL_CONST_P(VALUE obj)
{
return RB_IMMEDIATE_P(obj) || ! RB_TEST(obj);
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
/**
* Identical to RB_SPECIAL_CONST_P, except it returns a ::VALUE.
*
* @param[in] obj An arbitrary ruby object.
* @retval RUBY_Qtrue `obj` is a special constant.
* @retval RUBY_Qfalse Anything else.
*
* @internal
*
* This function is to mimic old rb_special_const_p macro but have anyone
* actually used its return value? Wasn't it just something no one needed?
*/
static inline VALUE
rb_special_const_p(VALUE obj)
{
return RB_SPECIAL_CONST_P(obj) * RUBY_Qtrue;
}
/**
* @cond INTERNAL_MACRO
* See [ruby-dev:27513] for the following macros.
*/
#define RUBY_Qfalse RBIMPL_CAST((VALUE)RUBY_Qfalse)
#define RUBY_Qtrue RBIMPL_CAST((VALUE)RUBY_Qtrue)
#define RUBY_Qnil RBIMPL_CAST((VALUE)RUBY_Qnil)
#define RUBY_Qundef RBIMPL_CAST((VALUE)RUBY_Qundef)
/** @endcond */
#endif /* RBIMPL_SPECIAL_CONSTS_H */
