[FFmpeg-devel] [PATCH] provide AV_BASE64_SIZE() macro

[Howard Chu]

M?ns Rullg?rd wrote:
> Michael Niedermayer<michaelni at gmx.at>  writes:
>
>> On Thu, Jun 03, 2010 at 11:00:49PM +0100, M?ns Rullg?rd wrote:
>>> Michael Niedermayer<michaelni at gmx.at>  writes:
>>>
>>>> On Thu, Jun 03, 2010 at 10:39:52PM +0100, M?ns Rullg?rd wrote:
>>>>> Michael Niedermayer<michaelni at gmx.at>  writes:
>>>>>
>>>>>> On Thu, Jun 03, 2010 at 01:50:06PM -0700, Howard Chu wrote:
>>>>>>> Just for convenience...
>>>>>>
>>>>>> IMHO this is making the code harder to understand
>>>>>
>>>>> How so?  It's an obscure calculation repeated multiple times.  That is
>>>>> exactly the kind of situation functions and macros were invented for.
>>>>
>>>> to me the calculation is clear,
>>>
>>> Because you happen to know exactly how base64 encoding works.  This is
>>> IMO not a reasonable requirement to place on users of the interface.
>>
>> its documented though, and i think its reasonable to expect users
>> to read the dox of what they use.
>
> By extension, one could argue that the base64 encoding is documented,
> wherefore we don't need to provide a function for it.
>
> I think a macro like this is good for the same reasons we have FFMAX
> and similar macros.
>
>>> Besides, the same rather complex calculation repeated numerous times
>>> is a recipe for trouble.  Sooner or later, someone will get it wrong
>>> in one place.  Then people will copy it from there, and the error will
>>> spread.  It's much better to put it all in a macro.
>>
>> i dont really see this as a big issue but if people prefer then iam not
>> against the macro

So, OK to commit, with the fixed comment?

+/**
+ * Calculate the output size needed to base64-encode x bytes.
+ */

>
> People have a remarkable knack for seeking out and copying the most
> broken example in the largest of code bases.  I'd rather not take that
> risk when it can be so easily avoided.
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/