Re: Storable issue

On Sat, Oct 27, 2007 at 09:36:38PM +0300, mokahol.gr
wrote:
> I have come across a case where two identical data
structrures are   
> stored in two different files using the storable
module. The only  
> thing is the filesizes of these  two files is
different, maybe by as  
> much as 10%.
> Any ideas why this is so?

$ perl -MData:umper
-MStorable -0777 -we 'foreach (ARGV) { print Dumper
Storable::read_magic do {open FH, $_ and <FH> }}'
/tmp/destdighash /tmp/destdighashnew        
$VAR1 = {
          'netorder' => 0,
          'hdrsize' => 13,
          'version' => 1,
          'file' => 1,
          'longsize' => 4,
          'ptrsize' => 4,
          'version_nv' => 1,
          'byteorder' => '1234',
          'major' => 1,
          'intsize' => 4
        };
$VAR1 = {
          'netorder' => 0,
          'hdrsize' => 15,
          'version' => '2.6',
          'minor' => 6,
          'file' => 1,
          'longsize' => 4,
          'ptrsize' => 4,
          'version_nv' => '2.006',
          'byteorder' => '1234',
          'nvsize' => 8,
          'major' => 2,
          'intsize' => 4
        };
$ ls -l /tmp/destdighash*
-rw-------  1 nick  wheel  8872 Nov  5 15:13
/tmp/destdighash
-rw-------  1 nick  wheel  7938 Nov  5 15:13
/tmp/destdighashnew


All I can say for sure is that the second file is generated
by a newer version
of Storable. I don't know why it is able to write out the
data in a more
compact format.

Nicholas Clark

Quoting Nicholas Clark <nickccl4.org>:
Thanks- the practical ramification is though that apparently
the two  
data structures are identical  and can be used
interchangeably,  
despite the fact that the files that store them have
different sizes.

> On Sat, Oct 27, 2007 at 09:36:38PM +0300, mokahol.gr
wrote:
>> I have come across a case where two identical data
structrures are
>> stored in two different files using the storable
module. The only
>> thing is the filesizes of these  two files is
different, maybe by as
>> much as 10%.
>> Any ideas why this is so?
>
> $ perl -MData:umper
-MStorable -0777 -we 'foreach (ARGV) { print   
> Dumper Storable::read_magic do {open FH, $_ and
<FH> }}'   
> /tmp/destdighash /tmp/destdighashnew
> $VAR1 = {
>           'netorder' => 0,
>           'hdrsize' => 13,
>           'version' => 1,
>           'file' => 1,
>           'longsize' => 4,
>           'ptrsize' => 4,
>           'version_nv' => 1,
>           'byteorder' => '1234',
>           'major' => 1,
>           'intsize' => 4
>         };
> $VAR1 = {
>           'netorder' => 0,
>           'hdrsize' => 15,
>           'version' => '2.6',
>           'minor' => 6,
>           'file' => 1,
>           'longsize' => 4,
>           'ptrsize' => 4,
>           'version_nv' => '2.006',
>           'byteorder' => '1234',
>           'nvsize' => 8,
>           'major' => 2,
>           'intsize' => 4
>         };
> $ ls -l /tmp/destdighash*
> -rw-------  1 nick  wheel  8872 Nov  5 15:13
/tmp/destdighash
> -rw-------  1 nick  wheel  7938 Nov  5 15:13
/tmp/destdighashnew
>
>
> All I can say for sure is that the second file is
generated by a   
> newer version
> of Storable. I don't know why it is able to write out
the data in a more
> compact format.
>
> Nicholas Clark
>