From: Warren Brown <wkb@...>
Date: 2003-04-05T05:13:29+09:00
Subject: Patch for bug in sprintf

All,

    I discovered a bug in sprintf.c.  When a width is specified for one of
the 'd' field types and a *positive* Bignum is supplied for the argument,
the string is padded by one too few characters:

%ruby -ve 'puts "(%12d)\n(%12d)\n(%12s)" %
[9876543210,-9876543210,9876543210]'
ruby 1.6.8 (2002-12-24) [i386-freebsd4.7]
( 9876543210)
( -9876543210)
(  9876543210)

    This is caused by the Bignum code decrementing the width even if there
is no sign character.  The patch to fix this is:

--- sprintf.c.original  Thu Dec 12 03:16:44 2002
+++ sprintf.c   Fri Apr  4 11:23:05 2003
@@ -436,14 +436,16 @@
                    if (s[0] == '-') {
                        s++;
                        sc = '-';
+                        width--;
                    }
                    else if (flags & FPLUS) {
                        sc = '+';
+                        width--;
                    }
                    else if (flags & FSPACE) {
                        sc = ' ';
+                        width--;
                    }
-                   width--;
                    goto format_integer;
                }
                if (!RBIGNUM(val)->sign) {

    This does not appear to be fixed in the latest snapshot:

%ruby -ve 'puts "(%12d)\n(%12d)\n(%12s)" %
[9876543210,-9876543210,9876543210]'
ruby 1.8.0 (2003-04-03) [i386-freebsd4.7]
( 9876543210)
( -9876543210)
(  9876543210)

    - Warren Brown