Re: [Bug-gnulib] missing licenses in gnulib

[Paul Eggert]

Robert Millan <address@hidden> writes:

> For these borrowed files from other GNU or free software projects, I think we
> still need an explicit note in the files distributed as part of gnulib.

OK, let's start with atanl.c and logl.c.  I see that glibc has fixed
this problem by adding a proper copyright notice.  Also, I see that
gnulib has departed from the glibc code in some cases where it doesn't
need to (and this arguably could introduce a bug).  So I installed
the following patch to fix both problems.

2004-10-06  Paul Eggert  <address@hidden>

        * lib/atanl.c, lib/logl.c:
        Add GPL notice, to match glibc's added LGPL notice.
        * lib/atanl.c (atanl): Keep the code as similar to glibc as possible.
        * lib/logl.c (logl): Keep the code as similar to glibc as possible.
        This avoids a potential constant-folding bug.

Index: lib/atanl.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/atanl.c,v
retrieving revision 1.1
diff -p -u -r1.1 atanl.c
--- lib/atanl.c 18 Feb 2003 17:05:23 -0000      1.1
+++ lib/atanl.c 6 Oct 2004 19:59:05 -0000
@@ -42,7 +42,22 @@
  *
  */
 
-/* Copyright 2001 by Stephen L. Moshier <address@hidden>  */
+/* Copyright 2001 by Stephen L. Moshier <address@hidden>
+
+   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; see the file COPYING.
+   If not, write to the Free Software Foundation,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
 #include "mathl.h"
 
@@ -161,19 +176,25 @@ atanl (long double x)
   int k, sign;
   long double t, u, p, q;
 
-  sign = (x < 0) ? -1 : 1;
+  sign = x < 0.0;
 
   /* Check for zero or NaN.  */
   if (x != x || x == 0.0)
     return x + x;
 
-  /* Check for infinity.  */
   if (x + x == x)
-    return sign * atantbl[83];
+    {
+      /* Infinity. */
+      if (sign)
+       return -atantbl[83];
+      else
+       return atantbl[83];
+    }
 
-  x *= sign;
+  if (sign)
+      x = -x;
 
-  if (x >= 10.25) /* 10.25 */
+  if (x >= 10.25)
     {
       k = 83;
       t = -1.0/x;
@@ -196,5 +217,9 @@ atanl (long double x)
   u = t * u * p / q  +  t;
 
   /* arctan x = arctan u  +  arctan t */
-  return sign * (atantbl[k] + u);
+  u = atantbl[k] + u;
+  if (sign)
+    return (-u);
+  else
+    return u;
 }
Index: lib/logl.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/logl.c,v
retrieving revision 1.1
diff -p -u -r1.1 logl.c
--- lib/logl.c  18 Feb 2003 17:05:23 -0000      1.1
+++ lib/logl.c  6 Oct 2004 19:59:05 -0000
@@ -46,7 +46,22 @@
 
 #include "mathl.h"
 
-/* Copyright 2001 by Stephen L. Moshier <address@hidden> */
+/* Copyright 2001 by Stephen L. Moshier <address@hidden>
+
+   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; see the file COPYING.
+   If not, write to the Free Software Foundation,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
 
 /* log(1+x) = x - .5 x^2 + x^3 l(x)
    -.0078125 <= x <= +.0078125
@@ -173,7 +188,8 @@ static const long double
 long double
 logl(long double x)
 {
-  long double z, y, w, u, t;
+  long double z, y, w;
+  long double u, t;
   unsigned int m;
   int k, e;
 
@@ -181,15 +197,19 @@ logl(long double x)
 
   /* log(0) = -infinity. */
   if (x == 0.0L)
-    return -0.5L / 0.0L;
-
+    {
+      return -0.5L / ZERO;
+    }
   /* log ( x < 0 ) = NaN */
   if (x < 0.0L)
-    return (x - x) / (x - x);
-
+    {
+      return (x - x) / ZERO;
+    }
   /* log (infinity or NaN) */
   if (x + x == x || x != x)
-    return x + x;
+    {
+      return x + x;
+    }
 
   /* Extract exponent and reduce domain to 0.703125 <= u < 1.40625  */
   x = frexpl(x, &e);
@@ -202,13 +222,13 @@ logl(long double x)
   /* On this interval the table is not used due to cancellation error.  */
   if ((x <= 1.0078125L) && (x >= 0.9921875L))
     {
+      z = x - 1.0L;
       k = 64;
       t = 1.0L;
-      z = x - 1.0L;
     }
   else
     {
-      k = floorl((x - 0.5L) * 128.0L);
+      k = floorl ((x - 0.5L) * 128.0L);
       t = 0.5L + k / 128.0L;
       z = (x - t) / t;
     }