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bug#9157: [PATCH] dd: sparse conv flag
From: |
Pádraig Brady |
Subject: |
bug#9157: [PATCH] dd: sparse conv flag |
Date: |
Mon, 27 Feb 2012 15:20:00 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:6.0) Gecko/20110816 Thunderbird/6.0 |
I recently noticed a use case for this feature:
https://review.openstack.org/#change,4435
But I managed to forget we had a patch pending for this,
and spent a couple of hours writing my own version :p
Well at least it's good practise for reviewing Roman's...
I notice Roman's seeks() the output for any run of NULs,
while mine only considers blocks of the full output block size.
Checking the full block is a bit more CPU efficient,
and gives a bit more control, so I'm marginally leaning
towards doing that?
Also Roman's doesn't handle the case where a seek
is done at the end of the file. In that case an ftruncate()
or write() is needed to correctly set the size.
Notes on my version attached are:
I first need to refactor is_nul() for use by cp too.
My version is advisory also
We may need to coalesce seeks to larger ones? something like cache_round()?
I thought it better to keep the code simple in this regard though
as it's probably not of practical concern.
I used conv= for bsd compat, rather than oflag=.
Needs tests and docs yet.
cheers,
Pádraig.
dd-sparse.patch
Description: Text Data
- bug#9157: [PATCH] dd: sparse conv flag,
Pádraig Brady <=
- bug#9157: [PATCH] dd: sparse conv flag, Paul Eggert, 2012/02/27
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/27
- bug#9157: [PATCH] dd: sparse conv flag, Paul Eggert, 2012/02/27
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/27
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/27
- bug#9157: [PATCH] dd: sparse conv flag, Paul Eggert, 2012/02/28
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/28
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/28
- bug#9157: [PATCH] dd: sparse conv flag, Paul Eggert, 2012/02/28
- bug#9157: [PATCH] dd: sparse conv flag, Pádraig Brady, 2012/02/28