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#ifndef RBIMPL_ARITHMETIC_LONG_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_ARITHMETIC_LONG_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 Arithmetic conversion between C's `long` and Ruby's.
*
* ### Q&A ###
*
* - Q: Why are INT2FIX etc. here, not in `int.h`?
*
* - A: Because they are in fact handling `long`. It seems someone did not
* understand the difference of `int` and `long` when they designed those
* macros.
*/
#include "ruby/internal/config.h"
#include "ruby/internal/arithmetic/fixnum.h" /* FIXABLE */
#include "ruby/internal/arithmetic/intptr_t.h" /* rb_int2big etc.*/
#include "ruby/internal/assume.h"
#include "ruby/internal/attr/artificial.h"
#include "ruby/internal/attr/cold.h"
#include "ruby/internal/attr/const.h"
#include "ruby/internal/attr/constexpr.h"
#include "ruby/internal/attr/noreturn.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/special_consts.h" /* FIXNUM_FLAG */
#include "ruby/internal/value.h"
#include "ruby/assert.h"
#define FIX2LONG RB_FIX2LONG
#define FIX2ULONG RB_FIX2ULONG
#define INT2FIX RB_INT2FIX
#define LONG2FIX RB_INT2FIX
#define LONG2NUM RB_LONG2NUM
#define NUM2LONG RB_NUM2LONG
#define NUM2ULONG RB_NUM2ULONG
#define RB_FIX2LONG rb_fix2long
#define RB_FIX2ULONG rb_fix2ulong
#define RB_LONG2FIX RB_INT2FIX
#define RB_LONG2NUM rb_long2num_inline
#define RB_NUM2LONG rb_num2long_inline
#define RB_NUM2ULONG rb_num2ulong_inline
#define RB_ULONG2NUM rb_ulong2num_inline
#define ULONG2NUM RB_ULONG2NUM
#define rb_fix_new RB_INT2FIX
#define rb_long2int rb_long2int_inline
/** @cond INTERNAL_MACRO */
#define RB_INT2FIX RB_INT2FIX
/** @endcond */
RBIMPL_SYMBOL_EXPORT_BEGIN()
RBIMPL_ATTR_NORETURN()
RBIMPL_ATTR_COLD()
void rb_out_of_int(SIGNED_VALUE num);
long rb_num2long(VALUE num);
unsigned long rb_num2ulong(VALUE num);
RBIMPL_SYMBOL_EXPORT_END()
RBIMPL_ATTR_CONST_UNLESS_DEBUG()
RBIMPL_ATTR_CONSTEXPR_UNLESS_DEBUG(CXX14)
RBIMPL_ATTR_ARTIFICIAL()
static inline VALUE
RB_INT2FIX(long i)
{
RBIMPL_ASSERT_OR_ASSUME(RB_FIXABLE(i));
/* :NOTE: VALUE can be wider than long. As j being unsigned, 2j+1 is fully
* defined. Also it can be compiled into a single LEA instruction. */
const unsigned long j = i;
const unsigned long k = 2 * j + RUBY_FIXNUM_FLAG;
const long l = k;
const SIGNED_VALUE m = l; /* Sign extend */
const VALUE n = m;
RBIMPL_ASSERT_OR_ASSUME(RB_FIXNUM_P(n));
return n;
}
static inline int
rb_long2int_inline(long n)
{
int i = RBIMPL_CAST((int)n);
if /* constexpr */ (sizeof(long) <= sizeof(int)) {
RBIMPL_ASSUME(i == n);
}
if (i != n)
rb_out_of_int(n);
return i;
}
RBIMPL_ATTR_CONST_UNLESS_DEBUG()
RBIMPL_ATTR_CONSTEXPR_UNLESS_DEBUG(CXX14)
static inline long
rbimpl_fix2long_by_idiv(VALUE x)
{
RBIMPL_ASSERT_OR_ASSUME(RB_FIXNUM_P(x));
/* :NOTE: VALUE can be wider than long. (x-1)/2 never overflows because
* RB_FIXNUM_P(x) holds. Also it has no portability issue like y>>1
* below. */
const SIGNED_VALUE y = x - RUBY_FIXNUM_FLAG;
const SIGNED_VALUE z = y / 2;
const long w = RBIMPL_CAST((long)z);
RBIMPL_ASSERT_OR_ASSUME(RB_FIXABLE(w));
return w;
}
RBIMPL_ATTR_CONST_UNLESS_DEBUG()
RBIMPL_ATTR_CONSTEXPR_UNLESS_DEBUG(CXX14)
static inline long
rbimpl_fix2long_by_shift(VALUE x)
{
RBIMPL_ASSERT_OR_ASSUME(RB_FIXNUM_P(x));
/* :NOTE: VALUE can be wider than long. If right shift is arithmetic, this
* is noticeably faster than above. */
const SIGNED_VALUE y = x;
const SIGNED_VALUE z = y >> 1;
const long w = RBIMPL_CAST((long)z);
RBIMPL_ASSERT_OR_ASSUME(RB_FIXABLE(w));
return w;
}
RBIMPL_ATTR_CONST()
RBIMPL_ATTR_CONSTEXPR(CXX11)
static inline bool
rbimpl_right_shift_is_arithmetic_p(void)
{
return (-1 >> 1) == -1;
}
RBIMPL_ATTR_CONST_UNLESS_DEBUG()
RBIMPL_ATTR_CONSTEXPR_UNLESS_DEBUG(CXX14)
static inline long
rb_fix2long(VALUE x)
{
if /* constexpr */ (rbimpl_right_shift_is_arithmetic_p()) {
return rbimpl_fix2long_by_shift(x);
}
else {
return rbimpl_fix2long_by_idiv(x);
}
}
RBIMPL_ATTR_CONST_UNLESS_DEBUG()
RBIMPL_ATTR_CONSTEXPR_UNLESS_DEBUG(CXX14)
static inline unsigned long
rb_fix2ulong(VALUE x)
{
RBIMPL_ASSERT_OR_ASSUME(RB_FIXNUM_P(x));
return rb_fix2long(x);
}
static inline long
rb_num2long_inline(VALUE x)
{
if (RB_FIXNUM_P(x))
return RB_FIX2LONG(x);
else
return rb_num2long(x);
}
static inline unsigned long
rb_num2ulong_inline(VALUE x)
{
/* This (negative fixnum would become a large unsigned long while negative
* bignum is an exception) has been THE behaviour of NUM2ULONG since the
* beginning. It is strange, but we can no longer change how it works at
* this moment. We have to get by with it. See also:
* https://bugs.ruby-lang.org/issues/9089 */
if (RB_FIXNUM_P(x))
return RB_FIX2ULONG(x);
else
return rb_num2ulong(x);
}
static inline VALUE
rb_long2num_inline(long v)
{
if (RB_FIXABLE(v))
return RB_LONG2FIX(v);
else
return rb_int2big(v);
}
static inline VALUE
rb_ulong2num_inline(unsigned long v)
{
if (RB_POSFIXABLE(v))
return RB_LONG2FIX(v);
else
return rb_uint2big(v);
}
/**
* @cond INTERNAL_MACRO
*
* Following overload is necessary because sometimes INT2FIX is used as a enum
* value (e.g. `enum { FOO = INT2FIX(0) };`). THIS IS NG in theory because a
* VALUE does not fit into an enum (which must be a signed int). But we cannot
* break existing codes.
*/
#if RBIMPL_HAS_ATTR_CONSTEXPR_CXX14
# /* C++ can write constexpr as enum values. */
#elif ! defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P)
# undef INT2FIX
# define INT2FIX(i) (RBIMPL_CAST((VALUE)(i)) << 1 | RUBY_FIXNUM_FLAG)
#else
# undef INT2FIX
# define INT2FIX(i) \
__builtin_choose_expr( \
__builtin_constant_p(i), \
RBIMPL_CAST((VALUE)(i)) << 1 | RUBY_FIXNUM_FLAG, \
RB_INT2FIX(i))
#endif
/** @endcond */
#endif /* RBIMPL_ARITHMETIC_LONG_H */
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