new module 'hypotl'

[Bruno Haible]

The hypotl module has no surprises.


2012-02-29  Bruno Haible  <address@hidden>

        New module 'hypotl'.
        * lib/math.in.h (hypotl): New declaration.
        * lib/hypotl.c: New file.
        * m4/hypotl.m4: New file.
        * m4/math_h.m4 (gl_MATH_H): Test whether hypotf is declared.
        (gl_MATH_H_DEFAULTS): Initialize GNULIB_HYPOTL, HAVE_HYPOTL.
        * modules/math (Makefile.am): Substitute GNULIB_HYPOTL, HAVE_HYPOTL.
        * modules/hypotl: New file.
        * tests/test-math-c++.cc: Check the hypotl declaration.
        * doc/posix-functions/hypotl.texi: Mention the new module.

================================ lib/hypotl.c ================================
/* Hypotenuse of a right-angled triangle.
   Copyright (C) 2012 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 3 of the License, 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, see <http://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <address@hidden>, 2012.  */

#include <config.h>

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

#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE

long double
hypotl (long double x, long double y)
{
  return hypot (x, y);
}

#else

long double
hypotl (long double x, long double y)
{
  if (isfinite (x) && isfinite (y))
    {
      /* Determine absolute values.  */
      x = fabsl (x);
      y = fabsl (y);

      {
        /* Find the bigger and the smaller one.  */
        long double a;
        long double b;

        if (x >= y)
          {
            a = x;
            b = y;
          }
        else
          {
            a = y;
            b = x;
          }
        /* Now 0 <= b <= a.  */

        {
          int e;
          long double an;
          long double bn;

          /* Write a = an * 2^e, b = bn * 2^e with 0 <= bn <= an < 1.  */
          an = frexpl (a, &e);
          bn = ldexpl (b, - e);

          {
            long double cn;

            /* Through the normalization, no unneeded overflow or underflow
               will occur here.  */
            cn = sqrtl (an * an + bn * bn);
            return ldexpl (cn, e);
          }
        }
      }
    }
  else
    {
      if (isinf (x) || isinf (y))
        /* x or y is infinite.  Return +Infinity.  */
        return HUGE_VALL;
      else
        /* x or y is NaN.  Return NaN.  */
        return x + y;
    }
}

#endif
================================ m4/hypotl.m4 ================================
# hypotl.m4 serial 1
dnl Copyright (C) 2012 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_HYPOTL],
[
  AC_REQUIRE([gl_MATH_H_DEFAULTS])
  AC_REQUIRE([gl_FUNC_HYPOT])

  dnl Test whether hypotl() exists. Assume that hypotl(), if it exists, is
  dnl defined in the same library as hypot().
  save_LIBS="$LIBS"
  LIBS="$LIBS $HYPOT_LIBM"
  AC_CHECK_FUNCS([hypotl])
  LIBS="$save_LIBS"
  if test $ac_cv_func_hypotl = yes; then
    HYPOTL_LIBM="$HYPOT_LIBM"
  else
    HAVE_HYPOTL=0
    dnl Find libraries needed to link lib/hypotl.c.
    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
      HYPOTL_LIBM="$HYPOT_LIBM"
    else
      AC_REQUIRE([gl_FUNC_FABSL])
      AC_REQUIRE([gl_FUNC_FREXPL])
      AC_REQUIRE([gl_FUNC_LDEXPL])
      AC_REQUIRE([gl_FUNC_SQRTL])
      HYPOTL_LIBM=
      dnl Append $FABSL_LIBM to HYPOTL_LIBM, avoiding gratuitous duplicates.
      case " $HYPOTL_LIBM " in
        *" $FABSL_LIBM "*) ;;
        *) HYPOTL_LIBM="$HYPOTL_LIBM $FABSL_LIBM" ;;
      esac
      dnl Append $FREXPL_LIBM to HYPOTL_LIBM, avoiding gratuitous duplicates.
      case " $HYPOTL_LIBM " in
        *" $FREXPL_LIBM "*) ;;
        *) HYPOTL_LIBM="$HYPOTL_LIBM $FREXPL_LIBM" ;;
      esac
      dnl Append $LDEXPL_LIBM to HYPOTL_LIBM, avoiding gratuitous duplicates.
      case " $HYPOTL_LIBM " in
        *" $LDEXPL_LIBM "*) ;;
        *) HYPOTL_LIBM="$HYPOTL_LIBM $LDEXPL_LIBM" ;;
      esac
      dnl Append $SQRTL_LIBM to HYPOTL_LIBM, avoiding gratuitous duplicates.
      case " $HYPOTL_LIBM " in
        *" $SQRTL_LIBM "*) ;;
        *) HYPOTL_LIBM="$HYPOTL_LIBM $SQRTL_LIBM" ;;
      esac
    fi
  fi
  AC_SUBST([HYPOTL_LIBM])
])
=============================== modules/hypotl ===============================
Description:
hypotl() function: length of a vector in the plane.

Files:
lib/hypotl.c
m4/hypotl.m4
m4/mathfunc.m4

Depends-on:
math
hypot           [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 1]
isfinite        [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]
fabsl           [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]
frexpl          [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]
ldexpl          [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]
sqrtl           [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]
isinf           [test $HAVE_HYPOTL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE 
= 0]

configure.ac:
gl_FUNC_HYPOTL
if test $HAVE_HYPOTL = 0; then
  AC_LIBOBJ([hypotl])
fi
gl_MATH_MODULE_INDICATOR([hypotl])

Makefile.am:

Include:
<math.h>

Link:
$(HYPOTL_LIBM)

License:
LGPL

Maintainer:
Bruno Haible
==============================================================================
--- doc/posix-functions/hypotl.texi.orig        Wed Feb 29 15:43:23 2012
+++ doc/posix-functions/hypotl.texi     Wed Feb 29 15:42:21 2012
@@ -4,15 +4,15 @@
 
 POSIX specification:@* 
@url{http://www.opengroup.org/onlinepubs/9699919799/functions/hypotl.html}
 
-Gnulib module: ---
+Gnulib module: hypotl
 
 Portability problems fixed by Gnulib:
 @itemize
address@hidden
+This function is missing on some platforms:
+FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 
6.5, Solaris 9, Cygwin, MSVC 9, Interix 3.5, BeOS.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
address@hidden
-This function is missing on some platforms:
-FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, IRIX 
6.5, Solaris 9, Cygwin, MSVC 9, Interix 3.5, BeOS.
 @end itemize
--- lib/math.in.h.orig  Wed Feb 29 15:43:23 2012
+++ lib/math.in.h       Wed Feb 29 14:33:08 2012
@@ -832,6 +832,21 @@
 # endif
 #endif
 
+/* Return sqrt(x^2+y^2).  */
+#if @GNULIB_HYPOTL@
+# if address@hidden@
+_GL_FUNCDECL_SYS (hypotl, long double, (long double x, long double y));
+# endif
+_GL_CXXALIAS_SYS (hypotl, long double, (long double x, long double y));
+_GL_CXXALIASWARN (hypotl);
+#elif defined GNULIB_POSIXCHECK
+# undef hypotl
+# if HAVE_RAW_DECL_HYPOTL
+_GL_WARN_ON_USE (hypotl, "hypotl is unportable - "
+                 "use gnulib module hypotl for portability");
+# endif
+#endif
+
 
 /* Return x * 2^exp.  */
 #if @GNULIB_LDEXPF@
--- m4/math_h.m4.orig   Wed Feb 29 15:43:23 2012
+++ m4/math_h.m4        Wed Feb 29 14:35:29 2012
@@ -1,4 +1,4 @@
-# math_h.m4 serial 72
+# math_h.m4 serial 73
 dnl Copyright (C) 2007-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -42,7 +42,7 @@
     [acosf acosl asinf asinl atanf atanl
      ceilf ceill copysign copysignf copysignl cosf cosl coshf
      expf expl fabsf fabsl floorf floorl fma fmaf fmal
-     fmod fmodf fmodl frexpf frexpl hypotf
+     fmod fmodf fmodl frexpf frexpl hypotf hypotl
      ldexpf ldexpl logb logf logl log10f log10l modf modff modfl powf
      remainder remainderf remainderl
      rint rintf rintl round roundf roundl sinf sinl sinhf sqrtf sqrtl
@@ -93,6 +93,7 @@
   GNULIB_FREXP=0;      AC_SUBST([GNULIB_FREXP])
   GNULIB_FREXPL=0;     AC_SUBST([GNULIB_FREXPL])
   GNULIB_HYPOTF=0;     AC_SUBST([GNULIB_HYPOTF])
+  GNULIB_HYPOTL=0;     AC_SUBST([GNULIB_HYPOTL])
   GNULIB_ISFINITE=0;   AC_SUBST([GNULIB_ISFINITE])
   GNULIB_ISINF=0;      AC_SUBST([GNULIB_ISINF])
   GNULIB_ISNAN=0;      AC_SUBST([GNULIB_ISNAN])
@@ -156,6 +157,7 @@
   HAVE_FMODL=1;                AC_SUBST([HAVE_FMODL])
   HAVE_FREXPF=1;               AC_SUBST([HAVE_FREXPF])
   HAVE_HYPOTF=1;               AC_SUBST([HAVE_HYPOTF])
+  HAVE_HYPOTL=1;               AC_SUBST([HAVE_HYPOTL])
   HAVE_ISNANF=1;               AC_SUBST([HAVE_ISNANF])
   HAVE_ISNAND=1;               AC_SUBST([HAVE_ISNAND])
   HAVE_ISNANL=1;               AC_SUBST([HAVE_ISNANL])
--- modules/math.orig   Wed Feb 29 15:43:23 2012
+++ modules/math        Wed Feb 29 14:36:03 2012
@@ -61,6 +61,7 @@
              -e 's/@''GNULIB_FREXP''@/$(GNULIB_FREXP)/g' \
              -e 's/@''GNULIB_FREXPL''@/$(GNULIB_FREXPL)/g' \
              -e 's/@''GNULIB_HYPOTF''@/$(GNULIB_HYPOTF)/g' \
+             -e 's/@''GNULIB_HYPOTL''@/$(GNULIB_HYPOTL)/g' \
              -e 's/@''GNULIB_ISFINITE''@/$(GNULIB_ISFINITE)/g' \
              -e 's/@''GNULIB_ISINF''@/$(GNULIB_ISINF)/g' \
              -e 's/@''GNULIB_ISNAN''@/$(GNULIB_ISNAN)/g' \
@@ -124,6 +125,7 @@
              -e 's|@''HAVE_FMODL''@|$(HAVE_FMODL)|g' \
              -e 's|@''HAVE_FREXPF''@|$(HAVE_FREXPF)|g' \
              -e 's|@''HAVE_HYPOTF''@|$(HAVE_HYPOTF)|g' \
+             -e 's|@''HAVE_HYPOTL''@|$(HAVE_HYPOTL)|g' \
              -e 's|@''HAVE_ISNANF''@|$(HAVE_ISNANF)|g' \
              -e 's|@''HAVE_ISNAND''@|$(HAVE_ISNAND)|g' \
              -e 's|@''HAVE_ISNANL''@|$(HAVE_ISNANL)|g' \
--- tests/test-math-c++.cc.orig Wed Feb 29 15:43:23 2012
+++ tests/test-math-c++.cc      Wed Feb 29 15:43:14 2012
@@ -159,6 +159,10 @@
 SIGNATURE_CHECK (GNULIB_NAMESPACE::hypotf, float, (float, float));
 #endif
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::hypot, double, (double, double));
+#if GNULIB_TEST_HYPOTL
+SIGNATURE_CHECK (GNULIB_NAMESPACE::hypotl, long double,
+                 (long double, long double));
+#endif
 
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::j0, double, (double));