[AC21.5] Handle leading + signs on bignums, etc.

[Jerry James]

Hi Giacomo,

Thanks for the bug report!

giacomo boffi <giacomo.boffi at polimi.it> wrote:
> i built xemacs from cvs, and i enabled the new bignums support
>
> M-x gnus RET
>
> failed, please see the attached backtrace
>
> i tried building a new copy of xemacs, from the same sources, except
> disabling bignum support, and gnus worked as fine as usual
>
> i'm sending this bug report from the xemacs with bignums enabled

It looks like the GMP function mpz_set_str chokes when the first
character is +.  In fact, mpq_set_str chokes also.  Well, we can safely
skip such plus signs, so let's just do it in case other libraries have
this defect as well.


src/ChangeLog addition:

2004-04-13  Jerry James  <james at xemacs.org>

	* data.c (Fstring_to_number): Skip leading + sign to avoid
	triggering random GMP behavior.
	* lread.c (read_atom): Ditto.
	* lread.c (isratio_string): Recognize ratio with leading + sign.
	* number.c (string_to_bignum): Skip leading + sign.


xemacs-21.5 source patch:
Diff command:   cvs -q diff -uN
Files affected: src/number.c src/lread.c src/data.c

Index: src/data.c
===================================================================
RCS file: /pack/xemacscvs/XEmacs/xemacs/src/data.c,v
retrieving revision 1.54
diff -d -u -u -r1.54 data.c
--- src/data.c	2004/04/08 15:23:09	1.54
+++ src/data.c	2004/04/13 15:16:41
@@ -1271,6 +1271,9 @@
 #ifdef HAVE_BIGFLOAT
       else
 	{
+	  /* GMP bigfloat_set_string returns random values with initial + */
+	  if (*p == '+')
+	    p++;
 	  bigfloat_set_prec (scratch_bigfloat, bigfloat_get_default_prec ());
 	  bigfloat_set_string (scratch_bigfloat, (const char *) p, b);
 	  return make_bigfloat_bf (scratch_bigfloat);
@@ -1281,12 +1284,19 @@
 #ifdef HAVE_RATIO
   if (qxestrchr (p, '/') != NULL)
     {
+      /* GMP ratio_set_string returns random values with initial + sign */
+      if (*p == '+')
+	p++;
       ratio_set_string (scratch_ratio, (const char *) p, b);
       return make_ratio_rt (scratch_ratio);
     }
 #endif /* HAVE_RATIO */
 
 #ifdef HAVE_BIGNUM
+  /* GMP bignum_set_string returns random values when the string starts with a
+     plus sign */
+  if (*p == '+')
+    p++;
   /* GMP bignum_set_string returns random values when fed an empty string */
   if (*p == '\0')
     return make_int (0);
Index: src/lread.c
===================================================================
RCS file: /pack/xemacscvs/XEmacs/xemacs/src/lread.c,v
retrieving revision 1.67
diff -d -u -u -r1.67 lread.c
--- src/lread.c	2004/04/07 03:49:00	1.67
+++ src/lread.c	2004/04/13 15:16:43
@@ -1851,6 +1851,9 @@
 #ifdef HAVE_RATIO
       if (isratio_string (read_ptr))
 	{
+	  /* GMP ratio_set_string returns random values with initial + sign */
+	  if (*read_ptr == '+')
+	    read_ptr++;
 	  ratio_set_string (scratch_ratio, read_ptr, 0);
 	  ratio_canonicalize (scratch_ratio);
 	  return Fcanonicalize_number (make_ratio_rt (scratch_ratio));
@@ -2673,8 +2676,8 @@
 int
 isratio_string (const char *cp)
 {
-  /* Possible minus sign */
-  if (*cp == '-')
+  /* Possible minus/plus sign */
+  if (*cp == '-' || *cp == '+')
     cp++;
 
   /* Numerator */
Index: src/number.c
===================================================================
RCS file: /pack/xemacscvs/XEmacs/xemacs/src/number.c,v
retrieving revision 1.4
diff -d -u -u -r1.4 number.c
--- src/number.c	2004/04/08 15:23:09	1.4
+++ src/number.c	2004/04/13 15:16:43
@@ -82,9 +82,15 @@
 			       bignum_hash, bignum_description, Lisp_Bignum);
 
 Lisp_Object
-string_to_bignum(const Ibyte *str, Bytecount len, int base)
+string_to_bignum (const Ibyte *str, Bytecount len, int base)
 {
   Lisp_Object b = make_bignum (0L);
+  /* GMP bignum_set_string returns random values with initial + sign */
+  if (*str == '+')
+    str++;
+  /* GMP bignum_set_string returns random values when fed an empty string */
+  if (*str == '\0')
+    return make_int (0);
   return (bignum_set_string (XBIGNUM_DATA (b), (const char *) str, base) < 0)
     ? Fsignal (Qinvalid_read_syntax,
 	       list3 (build_msg_string

-- 
Jerry James
http://www.ittc.ku.edu/~james/