new module 'truncf'

[Bruno Haible]

The truncf() function can be implemented just like trunc().

2007-10-04  Bruno Haible  <address@hidden>

        * modules/truncf: New file.
        * lib/trunc.c: Make paramerizable through USE_* macros.
        * lib/truncf.c: New file.
        * m4/truncf.m4: New file.
        * lib/math.in.h (truncf): New declaration.
        * m4/math_h.m4 (gl_MATH_H_DEFAULTS): Initialize GNULIB_TRUNCF and
        HAVE_DECL_TRUNCF.
        * modules/math (Makefile.am): Substitute also GNULIB_TRUNCF and
        HAVE_DECL_TRUNCF.
        * doc/functions/truncf.texi: Mention the 'truncf' module.

*** doc/functions/truncf.texi.orig      2007-10-05 01:05:03.000000000 +0200
--- doc/functions/truncf.texi   2007-10-04 12:38:09.000000000 +0200
***************
*** 4,18 ****
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/truncf.html}
  
! Gnulib module: ---
  
  Portability problems fixed by Gnulib:
  @itemize
  @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, AIX 5.1, HP-UX 11, Solaris 9, Interix 
3.5.
  @end itemize
--- 4,18 ----
  
  POSIX specification: @url{http://www.opengroup.org/susv3xsh/truncf.html}
  
! Gnulib module: truncf
  
  Portability problems fixed by Gnulib:
  @itemize
+ @item
+ This function is missing on some platforms:
+ FreeBSD 5.2.1, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, Solaris 9, Interix 
3.5.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @end itemize
*** lib/math.in.h.orig  2007-10-05 01:05:03.000000000 +0200
--- lib/math.in.h       2007-10-05 00:22:13.000000000 +0200
***************
*** 65,70 ****
--- 65,71 ----
       acosl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double asinl (long double x);
  #endif
***************
*** 76,81 ****
--- 77,83 ----
       asinl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double atanl (long double x);
  #endif
***************
*** 87,92 ****
--- 89,95 ----
       atanl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double ceill (long double x);
  #endif
***************
*** 98,103 ****
--- 101,107 ----
       ceill (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double cosl (long double x);
  #endif
***************
*** 109,114 ****
--- 113,119 ----
       cosl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double expl (long double x);
  #endif
***************
*** 120,125 ****
--- 125,131 ----
       expl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double floorl (long double x);
  #endif
***************
*** 131,136 ****
--- 137,143 ----
       floorl (x))
  #endif
  
+ 
  /* Write x as
       x = mantissa * 2^exp
     where
***************
*** 152,157 ****
--- 159,165 ----
       frexpl (x, e))
  #endif
  
+ 
  /* Return x * 2^exp.  */
  #if @GNULIB_LDEXPL@ && @REPLACE_LDEXPL@
  # define ldexpl rpl_ldexpl
***************
*** 167,172 ****
--- 175,181 ----
       ldexpl (x, e))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double logl (long double x);
  #endif
***************
*** 178,183 ****
--- 187,193 ----
       logl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double sinl (long double x);
  #endif
***************
*** 189,194 ****
--- 199,205 ----
       sinl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double sqrtl (long double x);
  #endif
***************
*** 200,205 ****
--- 211,217 ----
       sqrtl (x))
  #endif
  
+ 
  #if @GNULIB_MATHL@ || address@hidden@
  extern long double tanl (long double x);
  #endif
***************
*** 211,216 ****
--- 223,242 ----
       tanl (x))
  #endif
  
+ 
+ #if @GNULIB_TRUNCF@
+ # if address@hidden@
+ #  define truncf rpl_truncf
+ extern float truncf (float x);
+ # endif
+ #elif defined GNULIB_POSIXCHECK
+ # undef truncf
+ # define truncf(x) \
+     (GL_LINK_WARNING ("truncf is unportable - " \
+                       "use gnulib module truncf for portability"), \
+      truncf (x))
+ #endif
+ 
  #if @GNULIB_TRUNC@
  # if address@hidden@
  #  define trunc rpl_trunc
*** lib/trunc.c.orig    2007-10-05 01:05:03.000000000 +0200
--- lib/trunc.c 2007-10-05 00:57:25.000000000 +0200
***************
*** 24,41 ****
  
  #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
--- 24,59 ----
  
  #include <float.h>
  
! #ifdef USE_LONG_DOUBLE
! # define FUNC truncl
! # define DOUBLE long double
! # define MANT_DIG LDBL_MANT_DIG
! # define L_(literal) literal##L
! #elif ! defined USE_FLOAT
! # define FUNC trunc
! # define DOUBLE double
! # define MANT_DIG DBL_MANT_DIG
! # define L_(literal) literal
! #else /* defined USE_FLOAT */
! # define FUNC truncf
! # define DOUBLE float
! # define MANT_DIG FLT_MANT_DIG
! # define L_(literal) literal##f
! #endif
! 
! /* 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));
  
! DOUBLE
! FUNC (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
***************
*** 43,68 ****
       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;
  }
--- 61,86 ----
       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 > L_(0.0))
      {
        /* 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 -= L_(1.0);
      }
!   else if (z < L_(0.0))
      {
        /* 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 += L_(1.0);
      }
    return z;
  }
Changing permissions from . to 100644
*** lib/truncf.c.orig   2003-09-23 19:59:22.000000000 +0200
--- lib/truncf.c        2007-10-04 12:27:09.000000000 +0200
***************
*** 0 ****
--- 1,21 ----
+ /* 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 <address@hidden>, 2007.  */
+ 
+ #define USE_FLOAT
+ #include "trunc.c"
*** m4/math_h.m4.orig   2007-10-05 01:05:03.000000000 +0200
--- m4/math_h.m4        2007-10-04 12:46:10.000000000 +0200
***************
*** 25,30 ****
--- 25,31 ----
    GNULIB_MATHL=0;   AC_SUBST([GNULIB_MATHL])
    GNULIB_SIGNBIT=0; AC_SUBST([GNULIB_SIGNBIT])
    GNULIB_TRUNC=0;   AC_SUBST([GNULIB_TRUNC])
+   GNULIB_TRUNCF=0;  AC_SUBST([GNULIB_TRUNCF])
    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])
***************
*** 40,45 ****
--- 41,47 ----
    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])
+   HAVE_DECL_TRUNCF=1; AC_SUBST([HAVE_DECL_TRUNCF])
    REPLACE_FREXP=0;    AC_SUBST([REPLACE_FREXP])
    REPLACE_FREXPL=0;   AC_SUBST([REPLACE_FREXPL])
    REPLACE_LDEXPL=0;   AC_SUBST([REPLACE_LDEXPL])
Changing permissions from . to 100644
*** m4/truncf.m4.orig   2003-09-23 19:59:22.000000000 +0200
--- m4/truncf.m4        2007-10-05 01:01:19.000000000 +0200
***************
*** 0 ****
--- 1,48 ----
+ # truncf.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_TRUNCF],
+ [
+   AC_REQUIRE([gl_MATH_H_DEFAULTS])
+   dnl Persuade glibc <math.h> to declare truncf().
+   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+   dnl Test whether truncf() is declared.
+   AC_CHECK_DECLS([truncf], , , [#include <math.h>])
+   if test "$ac_cv_have_decl_truncf" = yes; then
+     dnl Test whether truncf() can be used without libm.
+     TRUNCF_LIBM=?
+     AC_TRY_LINK([
+        #ifndef __NO_MATH_INLINES
+        # define __NO_MATH_INLINES 1 /* for glibc */
+        #endif
+        #include <math.h>
+        float x;],
+       [x = truncf(x);],
+       [TRUNCF_LIBM=])
+     if test "$TRUNCF_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>
+          float x;],
+         [x = truncf(x);],
+         [TRUNCF_LIBM="-lm"])
+       LIBS="$save_LIBS"
+     fi
+     if test "$TRUNCF_LIBM" = "?"; then
+       TRUNCF_LIBM=
+     fi
+   else
+     HAVE_DECL_TRUNCF=0
+     AC_LIBOBJ([truncf])
+     TRUNCF_LIBM=
+   fi
+   AC_SUBST([HAVE_DECL_TRUNCF])
+   AC_SUBST([TRUNCF_LIBM])
+ ])
*** modules/math.orig   2007-10-05 01:05:03.000000000 +0200
--- modules/math        2007-10-04 12:45:48.000000000 +0200
***************
*** 28,33 ****
--- 28,34 ----
              -e 's|@''GNULIB_MATHL''@|$(GNULIB_MATHL)|g' \
              -e 's|@''GNULIB_SIGNBIT''@|$(GNULIB_SIGNBIT)|g' \
              -e 's|@''GNULIB_TRUNC''@|$(GNULIB_TRUNC)|g' \
+             -e 's|@''GNULIB_TRUNCF''@|$(GNULIB_TRUNCF)|g' \
              -e 's|@''HAVE_DECL_ACOSL''@|$(HAVE_DECL_ACOSL)|g' \
              -e 's|@''HAVE_DECL_ASINL''@|$(HAVE_DECL_ASINL)|g' \
              -e 's|@''HAVE_DECL_ATANL''@|$(HAVE_DECL_ATANL)|g' \
***************
*** 42,47 ****
--- 43,49 ----
              -e 's|@''HAVE_DECL_SQRTL''@|$(HAVE_DECL_SQRTL)|g' \
              -e 's|@''HAVE_DECL_TANL''@|$(HAVE_DECL_TANL)|g' \
              -e 's|@''HAVE_DECL_TRUNC''@|$(HAVE_DECL_TRUNC)|g' \
+             -e 's|@''HAVE_DECL_TRUNCF''@|$(HAVE_DECL_TRUNCF)|g' \
              -e 's|@''REPLACE_FREXP''@|$(REPLACE_FREXP)|g' \
              -e 's|@''REPLACE_FREXPL''@|$(REPLACE_FREXPL)|g' \
              -e 's|@''REPLACE_LDEXPL''@|$(REPLACE_LDEXPL)|g' \
Changing permissions from . to 100644
*** modules/truncf.orig 2003-09-23 19:59:22.000000000 +0200
--- modules/truncf      2007-10-05 00:54:39.000000000 +0200
***************
*** 0 ****
--- 1,31 ----
+ Description:
+ truncf() function: round towards zero.
+ 
+ Files:
+ lib/truncf.c
+ lib/trunc.c
+ m4/truncf.m4
+ 
+ Depends-on:
+ math
+ extensions
+ float
+ 
+ configure.ac:
+ gl_FUNC_TRUNCF
+ gl_MATH_MODULE_INDICATOR([truncf])
+ 
+ Makefile.am:
+ 
+ Include:
+ <math.h>
+ 
+ Link:
+ $(TRUNCF_LIBM)
+ 
+ License:
+ LGPL
+ 
+ Maintainer:
+ Bruno Haible
+