[erlang-questions] zlib compress and uncompress on bit string << 255, 3:2 >>.

Kostis Sagonas <>
Thu Oct 28 02:54:01 CEST 2010


rgowka1 wrote:
> Hi -
> 
> I am using zlib:compress and uncompress on bitstring.
> 
> The expression zlib:uncompress( zlib:compress ( << 255, 3:2 >>  )) =:=
> << 255, 3:2 >> is evaluating to false.
> 
> zlib:uncompress( zlib:compress ( << 255, 3:2 >>  )).
> <<"ÿ">>
> 
> << << X >> || << X:1 >>  <= <<"ÿ">>  >>.
> <<1,1,0,0,0,0,1,1,1,0,1,1,1,1,1,1>>
> 
>  << << X >> || << X:1 >>  <= << 255, 3:2 >>  >>.
> <<1,1,1,1,1,1,1,1,1,1>>
> 
> Is this a bug with the zlib library or am I missing something basic here?

What exactly makes you consider it a bug?

The manual clearly mentions that zlib:uncompress/1 returns a binary().
Why do you expect that equality of this term with a bitstring() which is 
not a binary() should succeed?

Kostis


More information about the erlang-questions mailing list