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usage of zlib z_block flush option

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  usage of zlib z_block flush option jefflad <jladouceur@gmail.com> - 2012-09-05 08:48 -0700
    Re: usage of zlib z_block flush option Mark Adler <madler@alumni.caltech.edu> - 2012-09-12 20:15 -0700
      Re: usage of zlib z_block flush option jefflad <jladouceur@gmail.com> - 2012-11-02 14:13 -0700
        Re: usage of zlib z_block flush option Mark Adler <google@madler.net> - 2013-02-08 20:36 -0800
      Re: usage of zlib z_block flush option glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-11-02 22:23 +0000

#1504 — usage of zlib z_block flush option

I'm attempting to locate what applications uses the Z_BLOCK zlib flush option but have only found one obscure user.

Just wondering if anyone knows if this flush option is commonly used ?

thanks

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#1514

On 2012-09-05 08:48:58 -0700, jefflad said:
> I'm attempting to locate what applications uses the Z_BLOCK zlib flush 
> option but have only found one obscure user.
> 
> Just wondering if anyone knows if this flush option is commonly used ?

How would anyone know the answer to that?

You can see examples of the cases where Z_BLOCK is useful by looking in 
the zlib source code distribution at examples/gzappend.c, 
examples/gzjoin.c, and examples/zran.c.

Mark

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#1593

On Wednesday, September 12, 2012 11:15:43 PM UTC-4, Mark Adler wrote:
> On 2012-09-05 08:48:58 -0700, jefflad said:
> 
> > I'm attempting to locate what applications uses the Z_BLOCK zlib flush 
> 
> > option but have only found one obscure user.
> 
> > 
> 
> > Just wondering if anyone knows if this flush option is commonly used ?
> 
> 
> 
> How would anyone know the answer to that?

Because they used it, or came across it.

Perhaps my question wasn't clear. I was trying to find use-cases where this is used.

I'm just trying to understand why this would be used.

For example, Apache uses it here because...

> 
> 
> 
> You can see examples of the cases where Z_BLOCK is useful by looking in 
> 
> the zlib source code distribution at examples/gzappend.c, 
> 
> examples/gzjoin.c, and examples/zran.c.

I wasn't looking for example usage as they do not represent real world use-cases.

> 
> 
> 
> Mark

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#1739

On Friday, November 2, 2012 2:13:20 PM UTC-7, jefflad wrote:
> I wasn't looking for example usage as they do not represent real world use-cases.

Fine.  Then take a look at pigz.  http://zlib.net/pigz/

Mark

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#1594

Mark Adler <madler@alumni.caltech.edu> wrote:
> On 2012-09-05 08:48:58 -0700, jefflad said:
>> I'm attempting to locate what applications uses the Z_BLOCK zlib flush 
>> option but have only found one obscure user.
 
>> Just wondering if anyone knows if this flush option is commonly used ?
 
> How would anyone know the answer to that?
 
> You can see examples of the cases where Z_BLOCK is useful by looking in 
> the zlib source code distribution at examples/gzappend.c, 
> examples/gzjoin.c, and examples/zran.c.

I am not sure where it is used, but I believe it can
be used to allow sort-of-direct access. 

The usual LZW algorithms flush the tables when they get full,
but compressors can flush at any time. If you add an index,
you can start decompression at specific points.

Also, if the compressor knows that the the source is changing
such that previous data won't be optimal for future compression,
it can flush the tables at that point.

-- glen

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