mv include/ruby/{impl,internal}

Devs do not love "impl".

1 files changed, 44 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..68544b760b
--- /dev/null
+++ b/include/ruby/internal/arithmetic/fixnum.h
@@ -0,0 +1,44 @@
+#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
+#define FIXNUM_MAX RUBY_FIXNUM_MAX
+#define FIXNUM_MIN RUBY_FIXNUM_MIN
+#define NEGFIXABLE RB_NEGFIXABLE
+#define POSFIXABLE RB_POSFIXABLE
+
+/*
+ * 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-stragne "< FIXNUM_MAX + 1" expression below is due to this.
+ */
+#define RB_POSFIXABLE(_) ((_) <  RUBY_FIXNUM_MAX + 1)
+#define RB_NEGFIXABLE(_) ((_) >= RUBY_FIXNUM_MIN)
+#define RB_FIXABLE(_)    (RB_POSFIXABLE(_) && RB_NEGFIXABLE(_))
+#define RUBY_FIXNUM_MAX  (LONG_MAX / 2)
+#define RUBY_FIXNUM_MIN  (LONG_MIN / 2)
+
+#endif /* RBIMPL_ARITHMETIC_FIXNUM_H */