rint on MSVC

[Bruno Haible]

On MSVC 9, the rint() function does not exist. This patch provides the
replacement.


2011-10-09  Bruno Haible  <address@hidden>

        rint: Support for MSVC.
        * lib/math.in.h (rint): New declaration.
        * lib/rint.c: New file.
        * m4/rint.m4: New file.
        * m4/math_h.m4 (gl_MATH_H): Test whether rint is declared.
        (gl_MATH_H_DEFAULTS): Initialize GNULIB_RINT, HAVE_RINT.
        * modules/math (Makefile.am): Substitute GNULIB_RINT, HAVE_RINT.
        * modules/rint (Description): Fix.
        (Files): Add lib/rint.c, m4/rint.m4.
        (Depends-on): Add math.
        (configure.ac): Invoke gl_FUNC_RINT, AC_LIBOBJ,
        gl_MATH_MODULE_INDICATOR.
        * tests/test-math-c++.cc: Check the declaration of rint.
        * modules/math-c++-tests (Makefile.am): Link test-math-c++ against
        $(RINT_LIBM). Needed on IRIX 6.5 with cc.
        * doc/posix-functions/rint.texi: Mention the replacement provided by
        the module.

================================= lib/rint.c =================================
/* Round according to the current rounding mode.
   Copyright (C) 2007, 2010-2011 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.  */

#include <config.h>

/* Specification.  */
#include <math.h>

#include <float.h>
#include <stdlib.h>

#undef MIN

#ifdef USE_LONG_DOUBLE
# define RINT rintl
# define DOUBLE long double
# define MANT_DIG LDBL_MANT_DIG
# define MIN LDBL_MIN
# define L_(literal) literal##L
#elif ! defined USE_FLOAT
# define RINT rint
# define DOUBLE double
# define MANT_DIG DBL_MANT_DIG
# define MIN DBL_MIN
# define L_(literal) literal
#else /* defined USE_FLOAT */
# define RINT rintf
# define DOUBLE float
# define MANT_DIG FLT_MANT_DIG
# define MIN FLT_MIN
# define L_(literal) literal##f
#endif

/* -0.0.  See minus-zero.h.  */
#if defined __hpux || defined __sgi || defined __ICC
# define MINUS_ZERO (-MIN * MIN)
#else
# define MINUS_ZERO L_(-0.0)
#endif

DOUBLE
RINT (DOUBLE x)
{
  /* 2^(MANT_DIG-1).  */
  static const DOUBLE TWO_MANT_DIG =
    /* Assume MANT_DIG <= 5 * 31.
       Use the identity
       n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5).  */
    (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
    * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
    * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
    * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
    * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));

  /* The use of 'volatile' guarantees that excess precision bits are dropped at
     each addition step and before the following comparison at the caller's
     site.  It is necessary on x86 systems where double-floats are not IEEE
     compliant by default, to avoid that the results become platform and
     compiler option dependent.  'volatile' is a portable alternative to gcc's
     -ffloat-store option.  */
  volatile DOUBLE z = x;

  /* Consider the current rounding mode, cf.
     <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/float.h.html>.
     This implementation supports only rounds-to-nearest.  */
  if (FLT_ROUNDS != 1)
    abort ();

  if (z > L_(0.0))
    {
      /* Avoid rounding error for x = 0.5 - 2^(-MANT_DIG-1).  */
      if (z < L_(0.5))
        z = L_(0.0);
      /* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1.  */
      else if (z < TWO_MANT_DIG)
        {
          /* Round to the next integer.  */
          z += TWO_MANT_DIG;
          z -= TWO_MANT_DIG;
        }
    }
  else if (z < L_(0.0))
    {
      /* Avoid rounding error for x = -(0.5 - 2^(-MANT_DIG-1)).  */
      if (z > - L_(0.5))
        z = MINUS_ZERO;
      /* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1.  */
      else if (z > -TWO_MANT_DIG)
        {
          /* Round to the next integer.  */
          z -= TWO_MANT_DIG;
          z += TWO_MANT_DIG;
        }
    }
  return z;
}
================================= m4/rint.m4 =================================
# rint.m4 serial 1
dnl Copyright (C) 2011 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_RINT],
[
  dnl Determine RINT_LIBM.
  gl_MATHFUNC([rint], [double], [(double)])
  if test $gl_cv_func_rint_no_libm = no \
     && test $gl_cv_func_rint_in_libm = no; then
    HAVE_RINT=0
    RINT_LIBM=
  fi
  AC_SUBST([RINT_LIBM])
])
==============================================================================
--- doc/posix-functions/rint.texi.orig  Sun Oct  9 18:36:22 2011
+++ doc/posix-functions/rint.texi       Sun Oct  9 17:32:33 2011
@@ -8,11 +8,11 @@
 
 Portability problems fixed by Gnulib:
 @itemize
address@hidden
+This function is missing on some platforms:
+MSVC 9.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
address@hidden
-This function is missing on some platforms:
-MSVC 9.
 @end itemize
--- lib/math.in.h.orig  Sun Oct  9 18:36:22 2011
+++ lib/math.in.h       Sun Oct  9 18:36:17 2011
@@ -712,6 +712,21 @@
 #endif
 
 
+#if @GNULIB_RINT@
+# if address@hidden@
+_GL_FUNCDECL_SYS (rint, double, (double x));
+# endif
+_GL_CXXALIAS_SYS (rint, double, (double x));
+_GL_CXXALIASWARN (rint);
+#elif defined GNULIB_POSIXCHECK
+# undef rint
+# if HAVE_RAW_DECL_RINT
+_GL_WARN_ON_USE (rint, "rint is unportable - "
+                 "use gnulib module rint for portability");
+# endif
+#endif
+
+
 #if @GNULIB_ROUNDF@
 # if @REPLACE_ROUNDF@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
--- m4/math_h.m4.orig   Sun Oct  9 18:36:22 2011
+++ m4/math_h.m4        Sun Oct  9 17:40:51 2011
@@ -1,4 +1,4 @@
-# math_h.m4 serial 50
+# math_h.m4 serial 51
 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -43,7 +43,7 @@
      ceilf ceill copysign copysignf copysignl cosf cosl coshf
      expf expl fabsf floorf floorl fmodf frexpf frexpl
      ldexpf ldexpl logb logf logl log10f modff powf
-     round roundf roundl sinf sinl sinhf sqrtf sqrtl
+     rint round roundf roundl sinf sinl sinhf sqrtf sqrtl
      tanf tanl tanhf trunc truncf truncl])
 ])
 
@@ -98,6 +98,7 @@
   GNULIB_LOG10F=0;    AC_SUBST([GNULIB_LOG10F])
   GNULIB_MODFF=0;     AC_SUBST([GNULIB_MODFF])
   GNULIB_POWF=0;      AC_SUBST([GNULIB_POWF])
+  GNULIB_RINT=0;      AC_SUBST([GNULIB_RINT])
   GNULIB_ROUND=0;     AC_SUBST([GNULIB_ROUND])
   GNULIB_ROUNDF=0;    AC_SUBST([GNULIB_ROUNDF])
   GNULIB_ROUNDL=0;    AC_SUBST([GNULIB_ROUNDL])
@@ -141,6 +142,7 @@
   HAVE_LOG10F=1;               AC_SUBST([HAVE_LOG10F])
   HAVE_MODFF=1;                AC_SUBST([HAVE_MODFF])
   HAVE_POWF=1;                 AC_SUBST([HAVE_POWF])
+  HAVE_RINT=1;                 AC_SUBST([HAVE_RINT])
   HAVE_SINF=1;                 AC_SUBST([HAVE_SINF])
   HAVE_SINL=1;                 AC_SUBST([HAVE_SINL])
   HAVE_SINHF=1;                AC_SUBST([HAVE_SINHF])
--- modules/math.orig   Sun Oct  9 18:36:22 2011
+++ modules/math        Sun Oct  9 17:41:33 2011
@@ -68,6 +68,7 @@
              -e 's/@''GNULIB_LOG10F''@/$(GNULIB_LOG10F)/g' \
              -e 's/@''GNULIB_MODFF''@/$(GNULIB_MODFF)/g' \
              -e 's/@''GNULIB_POWF''@/$(GNULIB_POWF)/g' \
+             -e 's/@''GNULIB_RINT''@/$(GNULIB_RINT)/g' \
              -e 's/@''GNULIB_ROUND''@/$(GNULIB_ROUND)/g' \
              -e 's/@''GNULIB_ROUNDF''@/$(GNULIB_ROUNDF)/g' \
              -e 's/@''GNULIB_ROUNDL''@/$(GNULIB_ROUNDL)/g' \
@@ -111,6 +112,7 @@
              -e 's|@''HAVE_LOG10F''@|$(HAVE_LOG10F)|g' \
              -e 's|@''HAVE_MODFF''@|$(HAVE_MODFF)|g' \
              -e 's|@''HAVE_POWF''@|$(HAVE_POWF)|g' \
+             -e 's|@''HAVE_RINT''@|$(HAVE_RINT)|g' \
              -e 's|@''HAVE_SINF''@|$(HAVE_SINF)|g' \
              -e 's|@''HAVE_SINL''@|$(HAVE_SINL)|g' \
              -e 's|@''HAVE_SINHF''@|$(HAVE_SINHF)|g' \
--- modules/math-c++-tests.orig Sun Oct  9 18:36:22 2011
+++ modules/math-c++-tests      Sun Oct  9 18:21:33 2011
@@ -16,5 +16,6 @@
 TESTS += test-math-c++
 check_PROGRAMS += test-math-c++
 test_math_c___SOURCES = test-math-c++.cc test-math-c++2.cc
-test_math_c___LDADD = $(LDADD) $(COPYSIGNL_LIBM)
+# These link dependencies are needed on IRIX 6.5 with cc.
+test_math_c___LDADD = $(LDADD) $(COPYSIGNL_LIBM) $(RINT_LIBM)
 endif
--- modules/rint.orig   Sun Oct  9 18:36:22 2011
+++ modules/rint        Sun Oct  9 17:58:52 2011
@@ -1,13 +1,20 @@
 Description:
-rint() function: round to nearest integer.
+rint() function: round according to the current rounding mode.
 
 Files:
+lib/rint.c
+m4/rint.m4
 m4/mathfunc.m4
 
 Depends-on:
+math
 
 configure.ac:
-gl_MATHFUNC([rint], [double], [(double)])
+gl_FUNC_RINT
+if test $HAVE_RINT = 0; then
+  AC_LIBOBJ([rint])
+fi
+gl_MATH_MODULE_INDICATOR([rint])
 
 Makefile.am:
 
--- tests/test-math-c++.cc.orig Sun Oct  9 18:36:22 2011
+++ tests/test-math-c++.cc      Sun Oct  9 17:34:53 2011
@@ -104,7 +104,9 @@
 #endif
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::pow, double, (double, double));
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::remainder, double, (double, double));
-//SIGNATURE_CHECK (GNULIB_NAMESPACE::rint, double, (double));
+#if GNULIB_TEST_RINT
+SIGNATURE_CHECK (GNULIB_NAMESPACE::rint, double, (double));
+#endif
 #if GNULIB_TEST_SINF
 SIGNATURE_CHECK (GNULIB_NAMESPACE::sinf, float, (float));
 #endif

-- 
In memoriam Oskar Schindler <http://en.wikipedia.org/wiki/Oskar_Schindler>
<http://www.shoah.dk/Courage/Schindler.htm>