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Diffstat (limited to 'include/ruby/internal/arithmetic/fixnum.h')
| -rw-r--r-- | include/ruby/internal/arithmetic/fixnum.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/include/ruby/internal/arithmetic/fixnum.h b/include/ruby/internal/arithmetic/fixnum.h new file mode 100644 index 0000000000..c8927ac824 --- /dev/null +++ b/include/ruby/internal/arithmetic/fixnum.h @@ -0,0 +1,60 @@ +#ifndef RBIMPL_ARITHMETIC_FIXNUM_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RBIMPL_ARITHMETIC_FIXNUM_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 Handling of integers formerly known as Fixnums. + */ +#include "ruby/backward/2/limits.h" + +#define FIXABLE RB_FIXABLE /**< @old{RB_FIXABLE} */ +#define FIXNUM_MAX RUBY_FIXNUM_MAX /**< @old{RUBY_FIXNUM_MAX} */ +#define FIXNUM_MIN RUBY_FIXNUM_MIN /**< @old{RUBY_FIXNUM_MIN} */ +#define NEGFIXABLE RB_NEGFIXABLE /**< @old{RB_NEGFIXABLE} */ +#define POSFIXABLE RB_POSFIXABLE /**< @old{RB_POSFIXABLE} */ + +/** + * Checks if the passed value is in range of fixnum, assuming it is a positive + * number. Can sometimes be useful for C's unsigned integer types. + * + * @internal + * + * FIXABLE can be applied to anything, from double to intmax_t. The problem is + * double. On a 64bit system RUBY_FIXNUM_MAX is 4,611,686,018,427,387,903, + * which is not representable by a double. The nearest value that a double can + * represent is 4,611,686,018,427,387,904, which is not fixable. The + * seemingly-strange "< FIXNUM_MAX + 1" expression below is due to this. + */ +#define RB_POSFIXABLE(_) ((_) < RUBY_FIXNUM_MAX + 1) + +/** + * Checks if the passed value is in range of fixnum, assuming it is a negative + * number. This is an implementation of #RB_FIXABLE. Rarely used stand alone. + */ +#define RB_NEGFIXABLE(_) ((_) >= RUBY_FIXNUM_MIN) + +/** Checks if the passed value is in range of fixnum */ +#define RB_FIXABLE(_) (RB_POSFIXABLE(_) && RB_NEGFIXABLE(_)) + +/** Maximum possible value that a fixnum can represent. */ +#define RUBY_FIXNUM_MAX (LONG_MAX / 2) + +/** Minimum possible value that a fixnum can represent. */ +#define RUBY_FIXNUM_MIN (LONG_MIN / 2) + +#endif /* RBIMPL_ARITHMETIC_FIXNUM_H */ |