New module 'trunc'.

diff --git a/doc/functions/trunc.texi b/doc/functions/trunc.texi
index ecb17e5..42e1b9d 100644 (file)
--- a/doc/functions/trunc.texi
+++ b/doc/functions/trunc.texi
@@ -4,15 +4,15 @@
 
 POSIX specification: @url{http://www.opengroup.org/susv3xsh/trunc.html}
 
-Gnulib module: ---
+Gnulib module: trunc
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function is missing on some platforms:
+FreeBSD 5.2.1, NetBSD 3.0, OpenBSD 3.8, Solaris 9, Interix 3.5.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
-@item
-This function is missing on some platforms:
-FreeBSD 5.2.1, NetBSD 3.0, OpenBSD 3.8, Solaris 9, Interix 3.5.
 @end itemize

diff --git a/lib/math.in.h b/lib/math.in.h
index 5138c95..2b6c11b 100644 (file)
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -211,6 +211,19 @@ extern long double tanl (long double x);
      tanl (x))
 #endif
 
+#if @GNULIB_TRUNC@
+# if !@HAVE_DECL_TRUNC@
+#  define trunc rpl_trunc
+extern double trunc (double x);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef trunc
+# define trunc(x) \
+    (GL_LINK_WARNING ("trunc is unportable - " \
+                      "use gnulib module trunc for portability"), \
+     trunc (x))
+#endif
+
 
 #if @GNULIB_SIGNBIT@
 # if @REPLACE_SIGNBIT@

diff --git a/lib/trunc.c b/lib/trunc.c
new file mode 100644 (file)
index 0000000..b74021e
--- /dev/null
+++ b/lib/trunc.c
@@ -0,0 +1,68 @@
+/* Round towards zero.
+   Copyright (C) 2007 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 Bruno Haible <bruno@clisp.org>, 2007.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <math.h>
+
+#include <float.h>
+
+/* 2^(DBL_MANT_DIG-1).  */
+static const double TWO_MANT_DIG =
+  /* Assume DBL_MANT_DIG <= 4 * 31.
+     Use the identity
+       n = floor(n/4) + floor((n+1)/4) + floor((n+2)/4) + floor((n+3)/4).  */
+  (double) (1U << ((DBL_MANT_DIG - 1) / 4))
+  * (double) (1U << ((DBL_MANT_DIG - 1 + 1) / 4))
+  * (double) (1U << ((DBL_MANT_DIG - 1 + 2) / 4))
+  * (double) (1U << ((DBL_MANT_DIG - 1 + 3) / 4));
+
+double
+trunc (double x)
+{
+  /* 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 y = x;
+  volatile double z = y;
+
+  if (z > 0)
+    {
+      /* Round to the next integer (nearest or up or down, doesn't matter).  */
+      z += TWO_MANT_DIG;
+      z -= TWO_MANT_DIG;
+      /* Enforce rounding down.  */
+      if (z > y)
+       z -= 1.0;
+    }
+  else if (z < 0)
+    {
+      /* Round to the next integer (nearest or up or down, doesn't matter).  */
+      z -= TWO_MANT_DIG;
+      z += TWO_MANT_DIG;
+      /* Enforce rounding up.  */
+      if (z < y)
+       z += 1.0;
+    }
+  return z;
+}

diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 21f3449..e57883a 100644 (file)
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 5
+# math_h.m4 serial 6
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -24,6 +24,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   GNULIB_LDEXPL=0;  AC_SUBST([GNULIB_LDEXPL])
   GNULIB_MATHL=0;   AC_SUBST([GNULIB_MATHL])
   GNULIB_SIGNBIT=0; AC_SUBST([GNULIB_SIGNBIT])
+  GNULIB_TRUNC=0;   AC_SUBST([GNULIB_TRUNC])
   dnl Assume proper GNU behavior unless another module says otherwise.
   HAVE_DECL_ACOSL=1;  AC_SUBST([HAVE_DECL_ACOSL])
   HAVE_DECL_ASINL=1;  AC_SUBST([HAVE_DECL_ASINL])
@@ -38,6 +39,7 @@ AC_DEFUN([gl_MATH_H_DEFAULTS],
   HAVE_DECL_SINL=1;   AC_SUBST([HAVE_DECL_SINL])
   HAVE_DECL_SQRTL=1;  AC_SUBST([HAVE_DECL_SQRTL])
   HAVE_DECL_TANL=1;   AC_SUBST([HAVE_DECL_TANL])
+  HAVE_DECL_TRUNC=1;  AC_SUBST([HAVE_DECL_TRUNC])
   REPLACE_FREXP=0;    AC_SUBST([REPLACE_FREXP])
   REPLACE_FREXPL=0;   AC_SUBST([REPLACE_FREXPL])
   REPLACE_LDEXPL=0;   AC_SUBST([REPLACE_LDEXPL])

diff --git a/m4/trunc.m4 b/m4/trunc.m4
new file mode 100644 (file)
index 0000000..58db4a1
--- /dev/null
+++ b/m4/trunc.m4
@@ -0,0 +1,46 @@
+# trunc.m4 serial 1
+dnl Copyright (C) 2007 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_TRUNC],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  dnl Test whether trunc() is declared.
+  AC_CHECK_DECLS([trunc], , , [#include <math.h>])
+  if test "$ac_cv_have_decl_trunc" = yes; then
+    dnl Test whether trunc() can be used without libm.
+    TRUNC_LIBM=?
+    AC_TRY_LINK([
+       #ifndef __NO_MATH_INLINES
+       # define __NO_MATH_INLINES 1 /* for glibc */
+       #endif
+       #include <math.h>
+       double x;],
+      [x = trunc(x);],
+      [TRUNC_LIBM=])
+    if test "$TRUNC_LIBM" = "?"; then
+      save_LIBS="$LIBS"
+      LIBS="$LIBS -lm"
+      AC_TRY_LINK([
+         #ifndef __NO_MATH_INLINES
+         # define __NO_MATH_INLINES 1 /* for glibc */
+         #endif
+         #include <math.h>
+         double x;],
+        [x = trunc(x);],
+        [TRUNC_LIBM="-lm"])
+      LIBS="$save_LIBS"
+    fi
+    if test "$TRUNC_LIBM" = "?"; then
+      TRUNC_LIBM=
+    fi
+  else
+    HAVE_DECL_TRUNC=0
+    AC_LIBOBJ([trunc])
+    TRUNC_LIBM=
+  fi
+  AC_SUBST([HAVE_DECL_TRUNC])
+  AC_SUBST([TRUNC_LIBM])
+])

diff --git a/modules/math b/modules/math
index ffb13da..5818999 100644 (file)
--- a/modules/math
+++ b/modules/math
@@ -27,6 +27,7 @@ math.h: math.in.h
              -e 's|@''GNULIB_LDEXPL''@|$(GNULIB_LDEXPL)|g' \
              -e 's|@''GNULIB_MATHL''@|$(GNULIB_MATHL)|g' \
              -e 's|@''GNULIB_SIGNBIT''@|$(GNULIB_SIGNBIT)|g' \
+             -e 's|@''GNULIB_TRUNC''@|$(GNULIB_TRUNC)|g' \
              -e 's|@''HAVE_DECL_ACOSL''@|$(HAVE_DECL_ACOSL)|g' \
              -e 's|@''HAVE_DECL_ASINL''@|$(HAVE_DECL_ASINL)|g' \
              -e 's|@''HAVE_DECL_ATANL''@|$(HAVE_DECL_ATANL)|g' \
@@ -40,6 +41,7 @@ math.h: math.in.h
              -e 's|@''HAVE_DECL_SINL''@|$(HAVE_DECL_SINL)|g' \
              -e 's|@''HAVE_DECL_SQRTL''@|$(HAVE_DECL_SQRTL)|g' \
              -e 's|@''HAVE_DECL_TANL''@|$(HAVE_DECL_TANL)|g' \
+             -e 's|@''HAVE_DECL_TRUNC''@|$(HAVE_DECL_TRUNC)|g' \
              -e 's|@''REPLACE_FREXP''@|$(REPLACE_FREXP)|g' \
              -e 's|@''REPLACE_FREXPL''@|$(REPLACE_FREXPL)|g' \
              -e 's|@''REPLACE_LDEXPL''@|$(REPLACE_LDEXPL)|g' \

diff --git a/modules/trunc b/modules/trunc
new file mode 100644 (file)
index 0000000..8153eda
--- /dev/null
+++ b/modules/trunc
@@ -0,0 +1,29 @@
+Description:
+trunc() function: round towards zero.
+
+Files:
+lib/trunc.c
+m4/trunc.m4
+
+Depends-on:
+math
+float
+
+configure.ac:
+gl_FUNC_TRUNC
+gl_MATH_MODULE_INDICATOR([trunc])
+
+Makefile.am:
+
+Include:
+<math.h>
+
+Link:
+$(TRUNC_LIBM)
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible
+