linux-kernel - Re: [PATCH 1/3] hexdump: more output formatting

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Date:	Wed, 30 May 2007 15:03:07 -0700
From:	Randy Dunlap <randy.dunlap@...cle.com>
To:	Satyam Sharma <satyam.sharma@...il.com>
CC:	Christoph Lameter <clameter@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, hugh@...itas.com
Subject: Re: [PATCH 1/3] hexdump: more output formatting

Satyam Sharma wrote:
> Hello Randy,
> 
>> Add a prefix string parameter.  Callers are responsible for any
>> string length/alignment that they want to see in the output.  I.e.,
>> callers should pad strings to achieve alignment if they want that.
>>
>> Add rowsize parameter.  This is the number of raw data bytes
>> to be printed per line.  Must be 16 or 32.
>>
>> Add a group_size parameter.  This allows callers to dump values
>> as 1-byte, 2-byte, 4-byte, or 8-byte numbers.  Default is
>> 1-byte numbers.  If the total length is not an even multiple
>> of group_size, 1-byte numbers are printed.
> 
> I wonder if (over-)engineering could hurt its adoption by more kernel
> users. There aren't very many 8-argument monsters in the kernel,
> and one would expect hexdump() to be easier on the fingers to
> type? :-) Why not just continue with reasonable default/fixed rowsize
> and groupsize values?

Yes, one can try to satisfy the users/callers by adapting to their
needs (wishes), which requires parameters or such; or one can have
no callers and end up with (around 11 currently) different hex dump
functions in the kernel source tree, but no users of lib/hexdump.c.

But it won't take much more "requirements" for me to drop the patch.

>> Add an "ascii" output parameter.  This causes ASCII data output
>> following the hex data output.
> [...]
>> +       if (!ascii)
>> +               goto nil;
>> +
>> +       if ((lx + 1) < linebuflen)
>>                 linebuf[lx++] = ' ';
>> -       }
>> -       for (j = 0; (j < 16) && (j < len) && (lx + 2) < linebuflen; j++)
>> +       for (j = 0; (j < rowsize) && (j < len) && (lx + 2) < 
>> linebuflen; j++)
>>                 linebuf[lx++] = isprint(ptr[j]) ? ptr[j] : '.';
>> +nil:
>>         linebuf[lx++] = '\0';
> 
> if (ascii) {
> ...
> }
> 
> linebuf[lx++] = '\0';
> 
> would help lose a goto and label.

The label has another reference already, so it wouldn't be lost.

But the if (ascii) block could be added...

-- 
~Randy
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