From: nobu.nokada@...
Date: 2003-11-18T09:51:07+09:00
Subject: Re: pack bug on 64-bit ruby

Hi,

At Tue, 18 Nov 2003 07:03:54 +0900,
Berger, Daniel wrote:
> The question I have now then is, if I've got code that uses
> [-1].pack("V"), how should I handle this on 64 bit platforms?  Is there
> a way to tell the bit-ness of Ruby from within Ruby?  Perhaps a
> RUBY_BITNESS constant?  Or is there some sort of "cross-bitness"
> approach I can use?

[-1].pack("v") gently gives "\377\377" on 32 bit platforms, so
it might be better to just mask, like as Perl.


* pack.c (pack_pack): mask for lower bits.  [ruby-talk:85377]

Index: pack.c
===================================================================
RCS file: /cvs/ruby/src/ruby/pack.c,v
retrieving revision 1.57
diff -u -2 -p -r1.57 pack.c
--- pack.c	9 Oct 2003 17:45:52 -0000	1.57
+++ pack.c	18 Nov 2003 00:45:32 -0000
@@ -676,4 +676,5 @@ pack_pack(ary, fmt)
 		if (NIL_P(from)) s = 0;
 		else {
+		    from = rb_funcall(from, '&', 1, INT2FIX(0xffff));
 		    s = NUM2INT(from);
 		}
@@ -690,5 +691,6 @@ pack_pack(ary, fmt)
 		if (NIL_P(from)) l = 0;
 		else {
-		    l = NATINT_U32(from);
+		    from = rb_funcall(from, '&', 1, UINT2NUM(0xffffffff));
+		    l = NUM2ULONG(from);
 		}
 		l = htonl(l);
@@ -704,4 +706,5 @@ pack_pack(ary, fmt)
 		if (NIL_P(from)) s = 0;
 		else {
+		    from = rb_funcall(from, '&', 1, INT2FIX(0xffff));
 		    s = NUM2INT(from);
 		}
@@ -718,5 +721,6 @@ pack_pack(ary, fmt)
 		if (NIL_P(from)) l = 0;
 		else {
-		    l = NATINT_U32(from);
+		    from = rb_funcall(from, '&', 1, UINT2NUM(0xffffffff));
+		    l = NUM2ULONG(from);
 		}
 		l = htovl(l);


-- 
Nobu Nakada