Forums » Ruby » Broken pack/unpack workaround

Array#pack and String#unpack are broken on OS X Tiger's ruby build. This
is known. I'm writing a lib where pack and unpack are used extensively
and would like to provide a workaround. Does anyone have such a
workaround already worked out? I can't think of a real easy way to do it
so I thought I'd check before running the gauntlet.

See also http://hans.fugal.net/yodl/blosxom.cgi/mac/ruby-pack.html

Here's a simplistic solution:

broken = (1 == [1].pack('n')[0])
if broken
  class String
    alias_method :broken_unpack, :unpack
    def unpack(spec)
      return broken_unpack(spec.tr('nvNV', 'vnVN'))
    end
  end
  class Array
    alias_method :broken_pack, :pack
    def pack(spec)
      return broken_pack(spec.tr('nvNV', 'vnVN'))
    end
  end
end

p([1].pack('n'))
p([1].pack('v'))
p([1].pack('N'))
p([1].pack('V'))

Paul.

Paul Battley wrote:

>       return broken_unpack(spec.tr('nvNV', 'vnVN'))

tr never occurred to me. That's perfect!