[2/2] new module 'isinf'

[Ben Pfaff]

PSPP wants to use 'isinf', so I've written up a new module for
the C99 'isinf' macro.  This second patch is the body of the
module.

I tested this to work on Debian GNU/Linux 'unstable' locally, and
via HP TestDrive on HP-UX 11i v2 and v3 on Itanium II and SuSE
Enterprise Server 10 on Opteron.

It fails on FreeBSD 6.2 on i386 (td152.testdrive.hp.com) with an
assertion failure on "ASSERT (!isinf (LDBL_MAX));", because that
system thinks that LDBL_MAX is infinite:

    $ cat > test.c
    #include <float.h>
    #include <stdio.h>

    int
    main(void)  
    {
      printf ("%Lf\n", LDBL_MAX);
      return 0;
    }
    $ gcc test.c
    $ ./a.out
    inf
    $ gcc -v
    Using built-in specs.
    Configured with: FreeBSD/i386 system compiler
    Thread model: posix
    gcc version 3.4.6 [FreeBSD] 20060305

The existing float module doesn't help, because the definition
that it provides for LDBL_MAX is identical to the definition
provided by the system.

I don't know what to do about that problem.

commit 25b1bcdbc504ddec001287fecdc405fc57e229f9
Author: Ben Pfaff <address@hidden>
Date:   Mon Jul 14 21:17:34 2008 -0700

    Add isinf module.

diff --git a/ChangeLog b/ChangeLog
index ac4a511..90e0f83 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,21 @@
 2008-07-14  Ben Pfaff  <address@hidden>
 
+       Add isinf module.
+       * lib/isinf.c: New file.
+       * lib/math.in.h: Define isinf macro if we have decided to replace
+       it.
+       * m4/isinf.m4: New file.
+       * m4/math_h.m4: Initialize and substitute variables for isinf
+       module.
+       * modules/isinf: New file.
+       * modules/isinf-tests: New file.
+       * modules/math: Add substitutions for new module.
+       * tests/test-isinf.c: New file.
+       * doc/posix-functions/isinf.texi: Mention new module.
+       * MODULES.html.sh: Mention new module.
+
+2008-07-14  Ben Pfaff  <address@hidden>
+
        Factor out some macros for use by additional modules.
        * m4/isnanf.m4 (gl_FLOAT_EXPONENT_LOCATION): Move into new file
        float-exponent.m4.
diff --git a/MODULES.html.sh b/MODULES.html.sh
index 118e3f5..e96bff6 100755
--- a/MODULES.html.sh
+++ b/MODULES.html.sh
@@ -2000,6 +2000,7 @@ func_all_modules ()
   func_module frexpl
   func_module frexpl-nolibm
   func_module isfinite
+  func_module isinf
   func_module isnan
   func_module isnanf
   func_module isnanf-nolibm
diff --git a/doc/posix-functions/isinf.texi b/doc/posix-functions/isinf.texi
index 8377f4f..19e793b 100644
--- a/doc/posix-functions/isinf.texi
+++ b/doc/posix-functions/isinf.texi
@@ -4,15 +4,15 @@
 
 POSIX specification: @url{http://www.opengroup.org/susv3xsh/isinf.html}
 
-Gnulib module: ---
+Gnulib module: isinf
 
 Portability problems fixed by Gnulib:
 @itemize
address@hidden
+This macro is missing on some platforms:
+AIX 4.3.2, IRIX 6.5, OSF/1 5.1, Solaris 10.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
address@hidden
-This function is missing on some platforms:
-AIX 4.3.2, IRIX 6.5, OSF/1 5.1, Solaris 10.
 @end itemize
diff --git a/lib/isinf.c b/lib/isinf.c
new file mode 100644
index 0000000..56ca9ae
--- /dev/null
+++ b/lib/isinf.c
@@ -0,0 +1,37 @@
+/* Test for positive or negative infinity.
+   Copyright (C) 2007-2008 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.  */
+
+/* Written by Ben Pfaff <address@hidden>, 2008. */
+
+#include <config.h>
+
+#include <float.h>
+
+int gl_isinff (float x)
+{
+  return x < -FLT_MAX || x > FLT_MAX;
+}
+
+int gl_isinfd (double x)
+{
+  return x < -DBL_MAX || x > DBL_MAX;
+}
+
+int gl_isinfl (long double x)
+{
+  return x < -LDBL_MAX || x > LDBL_MAX;
+}
diff --git a/lib/math.in.h b/lib/math.in.h
index 85f3785..4ff8fc9 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -381,6 +381,22 @@ extern int gl_isfinitel (long double x);
 #endif
 
 
+#if @GNULIB_ISINF@
+# if @REPLACE_ISINF@
+extern int gl_isinff (float x);
+extern int gl_isinfd (double x);
+extern int gl_isinfl (long double x);
+#  undef isinf
+#  define isinf(x) \
+   (sizeof (x) == sizeof (long double) ? gl_isinfl (x) : \
+    sizeof (x) == sizeof (double) ? gl_isinfd (x) : \
+    gl_isinff (x))
+# endif
+#elif defined GNULIB_POSIXCHECK
+  /* How to override a macro?  */
+#endif
+
+
 #if @GNULIB_ISNAN@
 # if @REPLACE_ISNAN@
 /* We can't just use the isnanf macro (e.g.) as exposed by
diff --git a/m4/isinf.m4 b/m4/isinf.m4
new file mode 100644
index 0000000..1b9e45a
--- /dev/null
+++ b/m4/isinf.m4
@@ -0,0 +1,49 @@
+# isinf.m4 serial 1
+dnl Copyright (C) 2007-2008 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_ISINF],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  dnl Persuade glibc <math.h> to declare isinf.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+  AC_CHECK_DECLS([isinf], , , [#include <math.h>])
+  if test "$ac_cv_have_decl_isinf" = yes; then
+    gl_CHECK_MATH_LIB([ISINF_LIBM], [x = isinf (x);])
+    if test "$ISINF_LIBM" != missing; then
+      dnl Test whether isinf() on 'long double' works.
+      gl_ISINFL_WORKS
+      case "$gl_cv_func_isinfl_works" in
+        *yes) ;;
+        *)    ISINF_LIBM=missing;;
+      esac
+    fi
+  fi
+  if test "$ac_cv_have_decl_isinf" != yes ||
+     test "$ISINF_LIBM" = missing; then
+    REPLACE_ISINF=1
+    AC_LIBOBJ([isinf])
+    ISINF_LIBM=
+  fi
+  AC_SUBST([REPLACE_ISINF])
+  AC_SUBST([ISINF_LIBM])
+])
+
+dnl Test whether isinf() correctly returns false for LDBL_MAX.
+AC_DEFUN([gl_ISINFL_WORKS],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_C_BIGENDIAN])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether isinf(long double) works], [gl_cv_func_isinfl_works],
+    [
+      AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <float.h>
+                                       #include <math.h>]],
+                                     [[return !!isinf(LDBL_MAX);]])],
+                    [gl_cv_func_isinfl_works=yes],
+                    [gl_cv_func_isinfl_works=no],
+                   [gl_cv_func_isinfl_works="guessing no"])
+    ])
+])
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 0348f24..b7a2738 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -51,6 +51,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   GNULIB_FREXP=0;    AC_SUBST([GNULIB_FREXP])
   GNULIB_FREXPL=0;   AC_SUBST([GNULIB_FREXPL])
   GNULIB_ISFINITE=0; AC_SUBST([GNULIB_ISFINITE])
+  GNULIB_ISINF=0;    AC_SUBST([GNULIB_ISINF])
   GNULIB_ISNAN=0;    AC_SUBST([GNULIB_ISNAN])
   GNULIB_LDEXPL=0;   AC_SUBST([GNULIB_LDEXPL])
   GNULIB_MATHL=0;    AC_SUBST([GNULIB_MATHL])
@@ -83,6 +84,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   REPLACE_FREXPL=0;            AC_SUBST([REPLACE_FREXPL])
   REPLACE_HUGE_VAL=0;          AC_SUBST([REPLACE_HUGE_VAL])
   REPLACE_ISFINITE=0;          AC_SUBST([REPLACE_ISFINITE])
+  REPLACE_ISINF=0;             AC_SUBST([REPLACE_ISINF])
   REPLACE_ISNAN=0;             AC_SUBST([REPLACE_ISNAN])
   REPLACE_LDEXPL=0;            AC_SUBST([REPLACE_LDEXPL])
   REPLACE_NAN=0;               AC_SUBST([REPLACE_NAN])
diff --git a/modules/isinf b/modules/isinf
new file mode 100644
index 0000000..c5e4dbd
--- /dev/null
+++ b/modules/isinf
@@ -0,0 +1,27 @@
+Description:
+isinf macro: test for positive or negative infinity
+
+Files:
+lib/isinf.c
+m4/isinf.m4
+m4/check-math-lib.m4
+
+Depends-on:
+float
+math
+extensions
+
+configure.ac:
+gl_ISINF
+gl_MATH_MODULE_INDICATOR([isinf])
+
+Makefile.am:
+
+Include:
+<math.h>
+
+License:
+GPL
+
+Maintainer:
+Ben Pfaff
diff --git a/modules/isinf-tests b/modules/isinf-tests
new file mode 100644
index 0000000..4928cd1
--- /dev/null
+++ b/modules/isinf-tests
@@ -0,0 +1,21 @@
+Files:
+m4/float-exponent.m4
+m4/double-exponent.m4
+m4/ldouble-exponent.m4
+tests/test-isinf.c
+
+Depends-on:
+float
+
+configure.ac:
+gl_FLOAT_EXPONENT_LOCATION
+gl_DOUBLE_EXPONENT_LOCATION
+gl_LONG_DOUBLE_EXPONENT_LOCATION
+
+Makefile.am:
+TESTS += test-isinf
+check_PROGRAMS += test-isinf
+test_isinf_LDADD = $(LDADD) @ISINF_LIBM@
+
+License:
+GPL
diff --git a/modules/math b/modules/math
index 4be8501..20ec1d6 100644
--- a/modules/math
+++ b/modules/math
@@ -29,6 +29,7 @@ math.h: math.in.h
              -e 's|@''GNULIB_FREXP''@|$(GNULIB_FREXP)|g' \
              -e 's|@''GNULIB_FREXPL''@|$(GNULIB_FREXPL)|g' \
              -e 's|@''GNULIB_ISFINITE''@|$(GNULIB_ISFINITE)|g' \
+             -e 's|@''GNULIB_ISINF''@|$(GNULIB_ISINF)|g' \
              -e 's|@''GNULIB_ISNAN''@|$(GNULIB_ISNAN)|g' \
              -e 's|@''GNULIB_LDEXPL''@|$(GNULIB_LDEXPL)|g' \
              -e 's|@''GNULIB_MATHL''@|$(GNULIB_MATHL)|g' \
@@ -60,6 +61,7 @@ math.h: math.in.h
              -e 's|@''REPLACE_FREXPL''@|$(REPLACE_FREXPL)|g' \
              -e 's|@''REPLACE_HUGE_VAL''@|$(REPLACE_HUGE_VAL)|g' \
              -e 's|@''REPLACE_ISFINITE''@|$(REPLACE_ISFINITE)|g' \
+             -e 's|@''REPLACE_ISINF''@|$(REPLACE_ISINF)|g' \
              -e 's|@''REPLACE_ISNAN''@|$(REPLACE_ISNAN)|g' \
              -e 's|@''REPLACE_LDEXPL''@|$(REPLACE_LDEXPL)|g' \
              -e 's|@''REPLACE_NAN''@|$(REPLACE_NAN)|g' \
diff --git a/tests/test-isinf.c b/tests/test-isinf.c
new file mode 100644
index 0000000..43c77ad
--- /dev/null
+++ b/tests/test-isinf.c
@@ -0,0 +1,249 @@
+/* Test of isinf() substitute.
+   Copyright (C) 2007-2008 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 Ben Pfaff, 2008, using Bruno Haible's code as a
+   template. */
+
+#include <config.h>
+
+#include <float.h>
+#include <limits.h>
+#include <math.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define ASSERT(expr) \
+  do                                                                        \
+    {                                                                       \
+      if (!(expr))                                                          \
+        {                                                                   \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                  \
+          abort ();                                                         \
+        }                                                                   \
+    }                                                                       \
+  while (0)
+
+float zerof = 0.0f;
+double zerod = 0.0;
+long double zerol = 0.0L;
+
+static void
+test_isinff ()
+{
+  /* Zero. */
+  ASSERT (!isinf (0.0f));
+  /* Subnormal values. */
+  ASSERT (!isinf (FLT_MIN / 2));
+  ASSERT (!isinf (-FLT_MIN / 2));
+  /* Finite values.  */
+  ASSERT (!isinf (3.141f));
+  ASSERT (!isinf (3.141e30f));
+  ASSERT (!isinf (3.141e-30f));
+  ASSERT (!isinf (-2.718f));
+  ASSERT (!isinf (-2.718e30f));
+  ASSERT (!isinf (-2.718e-30f));
+  ASSERT (!isinf (FLT_MAX));
+  ASSERT (!isinf (-FLT_MAX));
+  /* Infinite values.  */
+  ASSERT (isinf (1.0f / 0.0f));
+  ASSERT (isinf (-1.0f / 0.0f));
+  /* Quiet NaN.  */
+  ASSERT (!isinf (zerof / zerof));
+#if defined FLT_EXPBIT0_WORD && defined FLT_EXPBIT0_BIT
+  /* Signalling NaN.  */
+  {
+    #define NWORDS \
+      ((sizeof (float) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+    typedef union { float value; unsigned int word[NWORDS]; } memory_float;
+    memory_float m;
+    m.value = zerof / zerof;
+# if FLT_EXPBIT0_BIT > 0
+    m.word[FLT_EXPBIT0_WORD] ^= (unsigned int) 1 << (FLT_EXPBIT0_BIT - 1);
+# else
+    m.word[FLT_EXPBIT0_WORD + (FLT_EXPBIT0_WORD < NWORDS / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    if (FLT_EXPBIT0_WORD < NWORDS / 2)
+      m.word[FLT_EXPBIT0_WORD + 1] |= (unsigned int) 1 << FLT_EXPBIT0_BIT;
+    else
+      m.word[0] |= (unsigned int) 1;
+    ASSERT (!isinf (m.value));
+    #undef NWORDS
+  }
+#endif
+}
+
+static void
+test_isinfd ()
+{
+  /* Zero. */
+  ASSERT (!isinf (0.0));
+  /* Subnormal values. */
+  ASSERT (!isinf (DBL_MIN / 2));
+  ASSERT (!isinf (-DBL_MIN / 2));
+  /* Finite values. */
+  ASSERT (!isinf (3.141));
+  ASSERT (!isinf (3.141e30));
+  ASSERT (!isinf (3.141e-30));
+  ASSERT (!isinf (-2.718));
+  ASSERT (!isinf (-2.718e30));
+  ASSERT (!isinf (-2.718e-30));
+  ASSERT (!isinf (DBL_MAX));
+  ASSERT (!isinf (-DBL_MAX));
+  /* Infinite values.  */
+  ASSERT (isinf (1.0 / 0.0));
+  ASSERT (isinf (-1.0 / 0.0));
+  /* Quiet NaN.  */
+  ASSERT (!isinf (zerod / zerod));
+#if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
+  /* Signalling NaN.  */
+  {
+    #define NWORDS \
+      ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+    typedef union { double value; unsigned int word[NWORDS]; } memory_double;
+    memory_double m;
+    m.value = zerod / zerod;
+# if DBL_EXPBIT0_BIT > 0
+    m.word[DBL_EXPBIT0_WORD] ^= (unsigned int) 1 << (DBL_EXPBIT0_BIT - 1);
+# else
+    m.word[DBL_EXPBIT0_WORD + (DBL_EXPBIT0_WORD < NWORDS / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    m.word[DBL_EXPBIT0_WORD + (DBL_EXPBIT0_WORD < NWORDS / 2 ? 1 : - 1)]
+      |= (unsigned int) 1 << DBL_EXPBIT0_BIT;
+    ASSERT (!isinf (m.value));
+    #undef NWORDS
+  }
+#endif
+}
+
+static void
+test_isinfl ()
+{
+  #define NWORDS \
+    ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned 
int))
+  typedef union { unsigned int word[NWORDS]; long double value; }
+          memory_long_double;
+
+  /* Zero. */
+  ASSERT (!isinf (0.0L));
+  /* Subnormal values. */
+  ASSERT (!isinf (LDBL_MIN / 2));
+  ASSERT (!isinf (-LDBL_MIN / 2));
+  /* Finite values. */
+  ASSERT (!isinf (3.141L));
+  ASSERT (!isinf (3.141e30L));
+  ASSERT (!isinf (3.141e-30L));
+  ASSERT (!isinf (-2.718L));
+  ASSERT (!isinf (-2.718e30L));
+  ASSERT (!isinf (-2.718e-30L));
+  ASSERT (!isinf (LDBL_MAX));
+  ASSERT (!isinf (-LDBL_MAX));
+  /* Infinite values.  */
+  ASSERT (isinf (1.0L / 0.0L));
+  ASSERT (isinf (-1.0L / 0.0L));
+  /* Quiet NaN.  */
+  ASSERT (!isinf (zerol / zerol));
+
+#if defined LDBL_EXPBIT0_WORD && defined LDBL_EXPBIT0_BIT
+  /* A bit pattern that is different from a Quiet NaN.  With a bit of luck,
+     it's a Signalling NaN.  */
+  {
+    memory_long_double m;
+    m.value = zerol / zerol;
+# if LDBL_EXPBIT0_BIT > 0
+    m.word[LDBL_EXPBIT0_WORD] ^= (unsigned int) 1 << (LDBL_EXPBIT0_BIT - 1);
+# else
+    m.word[LDBL_EXPBIT0_WORD + (LDBL_EXPBIT0_WORD < NWORDS / 2 ? 1 : - 1)]
+      ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
+# endif
+    m.word[LDBL_EXPBIT0_WORD + (LDBL_EXPBIT0_WORD < NWORDS / 2 ? 1 : - 1)]
+      |= (unsigned int) 1 << LDBL_EXPBIT0_BIT;
+    ASSERT (!isinf (m.value));
+  }
+#endif
+
+#if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined 
__amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined 
_M_IX86 || defined _X86_))
+/* Representation of an 80-bit 'long double' as an initializer for a sequence
+   of 'unsigned int' words.  */
+# ifdef WORDS_BIGENDIAN
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
+       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
+       (unsigned int) (mantlo) << 16                                        \
+     }
+# else
+#  define LDBL80_WORDS(exponent,manthi,mantlo) \
+     { mantlo, manthi, exponent }
+# endif
+  { /* Quiet NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  {
+    /* Signalling NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  /* The isnanl function should recognize Pseudo-NaNs, Pseudo-Infinities,
+     Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
+       Intel IA-64 Architecture Software Developer's Manual, Volume 1:
+       Application Architecture.
+       Table 5-2 "Floating-Point Register Encodings"
+       Figure 5-6 "Memory to Floating-Point Register Data Translation"
+   */
+  { /* Pseudo-NaN.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  { /* Pseudo-Infinity.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  { /* Pseudo-Zero.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  { /* Unnormalized number.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+  { /* Pseudo-Denormal.  */
+    static memory_long_double x =
+      { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
+    ASSERT (!isinf (x.value));
+  }
+#endif
+
+  #undef NWORDS
+}
+
+int
+main ()
+{
+  test_isinff ();
+  test_isinfd ();
+  test_isinfl ();
+  return 0;
+}

-- 
Ben Pfaff 
http://benpfaff.org