From: Bruno Haible <bruno@clisp.org>
Date: Mon, 28 Aug 2006 12:54:20 +0000 (+0000)
Subject: New module 'imaxdiv'.
X-Git-Tag: cvs-readonly~1980
X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=eb6d07a070b018aa129327c85dd7ef5f9ed44150;p=gnulib.git

New module 'imaxdiv'.
---

diff --git a/lib/imaxdiv.c b/lib/imaxdiv.c
new file mode 100644
index 000000000..1bbfe0e42
--- /dev/null
+++ b/lib/imaxdiv.c
@@ -0,0 +1,66 @@
+/* imaxdiv() function: division of 'intmax_t'.
+   Copyright (C) 2006 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification.  */
+#include <inttypes.h>
+
+#include <stdlib.h>
+
+imaxdiv_t
+imaxdiv (intmax_t numer, intmax_t denom)
+{
+  imaxdiv_t result;
+
+  result.quot = numer / denom;
+  result.rem = numer % denom;
+
+  /* Verify the requirements of ISO C 99 section 6.5.5 paragraph 6:
+     "When integers are divided, the result of the / operator is the
+      algebraic quotient with any fractional part discarded.  (This is
+      often called "truncation toward zero".)  If the quotient a/b is
+      representable, the expression (a/b)*b + a%b shall equal a."  */
+  if (!(denom == 0
+	|| (INTMAX_MIN + INTMAX_MAX < 0
+	    && denom == -1
+	    && numer < - INTMAX_MAX)))
+    {
+      if (!(result.quot * denom + result.rem == numer))
+	/* The compiler's implementation of / and % is broken.  */
+	abort ();
+      if (!(numer >= 0
+	    ? result.rem >= 0
+	      && (denom >= 0
+		  ? result.rem < denom
+		  : /* Don't write  result.rem < - denom,
+		       as it gives integer overflow if denom == INTMAX_MIN.  */
+		    - result.rem > denom)
+	    : result.rem <= 0
+	      && (denom >= 0
+		  ? result.rem > - denom
+		  : result.rem > denom)))
+	/* The compiler's implementation of / and % may be ok according to
+	   C89, but not to C99.  Please report this to <bug-gnulib@ngu.org>.
+	   This might be a big portability problem.  */
+	abort ();
+    }
+
+  return result;
+}
diff --git a/m4/imaxdiv.m4 b/m4/imaxdiv.m4
new file mode 100644
index 000000000..59118d229
--- /dev/null
+++ b/m4/imaxdiv.m4
@@ -0,0 +1,17 @@
+# imaxdiv.m4 serial 1
+dnl Copyright (C) 2006 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_IMAXDIV],
+[
+  AC_REQUIRE([gl_INTTYPES_H])
+  if test "$ac_cv_have_decl_imaxdiv" != yes; then
+    AC_LIBOBJ([imaxdiv])
+    gl_PREREQ_IMAXDIV
+  fi
+])
+
+# Prerequisites of lib/imaxdiv.c.
+AC_DEFUN([gl_PREREQ_IMAXDIV], [:])
diff --git a/modules/imaxdiv b/modules/imaxdiv
new file mode 100644
index 000000000..621d1f305
--- /dev/null
+++ b/modules/imaxdiv
@@ -0,0 +1,23 @@
+Description:
+imaxdiv() function: division of 'intmax_t'.
+
+Files:
+lib/imaxdiv.c
+m4/imaxdiv.m4
+
+Depends-on:
+inttypes
+
+configure.ac:
+gl_FUNC_IMAXDIV
+
+Makefile.am:
+
+Include:
+<inttypes.h>
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible