[FFmpeg-devel] [PATCHv2] avutil/crc: avoid needless space wastage of hardcoded crc table

[James Almer]

On 12/1/2015 10:35 PM, Ganesh Ajjanagadde wrote:
> On Tue, Dec 1, 2015 at 8:08 PM, James Almer <jamrial at gmail.com> wrote:
>> On 12/1/2015 9:53 PM, Ganesh Ajjanagadde wrote:
>>> There was no reason AFAIK for making AV_CRC_24_IEEE 12. This simply
>>> resulted in wasted space under --enable-hardcoded-tables:
>>> dynamic: 1318672 libavutil/libavutil.so.55
>>> old    : 1330680 libavutil/libavutil.so.55
>>> new    : 1326488 libavutil/libavutil.so.55
>>>
>>> Minor version number is bumped, with ifdefry due to API breakage.
>>>
>>> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
>>> ---
>>>  libavutil/crc.h     | 4 ++++
>>>  libavutil/version.h | 5 ++++-
>>>  2 files changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/libavutil/crc.h b/libavutil/crc.h
>>> index e86bf1d..9af4421 100644
>>> --- a/libavutil/crc.h
>>> +++ b/libavutil/crc.h
>>> @@ -40,7 +40,11 @@ typedef enum {
>>>      AV_CRC_32_IEEE,
>>>      AV_CRC_32_IEEE_LE,  /*< reversed bitorder version of AV_CRC_32_IEEE */
>>>      AV_CRC_16_ANSI_LE,  /*< reversed bitorder version of AV_CRC_16_ANSI */
>>> +#if FF_API_CRC_BIG_TABLE
>>>      AV_CRC_24_IEEE = 12,
>>> +#else
>>> +    AV_CRC_24_IEEE,
>>> +#endif /* FF_API_CRC_BIG_TABLE */
>>>      AV_CRC_MAX,         /*< Not part of public API! Do not use outside libavutil. */
>>>  }AVCRCId;
>>>
>>> diff --git a/libavutil/version.h b/libavutil/version.h
>>> index e0ddfd2..67e778a 100644
>>> --- a/libavutil/version.h
>>> +++ b/libavutil/version.h
>>> @@ -56,7 +56,7 @@
>>>   */
>>>
>>>  #define LIBAVUTIL_VERSION_MAJOR  55
>>> -#define LIBAVUTIL_VERSION_MINOR   9
>>> +#define LIBAVUTIL_VERSION_MINOR  10
>>>  #define LIBAVUTIL_VERSION_MICRO 100
>>>
>>>  #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
>>> @@ -108,6 +108,9 @@
>>>  #ifndef FF_API_ERROR_FRAME
>>>  #define FF_API_ERROR_FRAME              (LIBAVUTIL_VERSION_MAJOR < 56)
>>>  #endif
>>> +#ifndef FF_API_CRC_BIG_TABLE
>>> +#define FF_API_CRC_BIG_TABLE            (LIBAVUTIL_VERSION_INT < AV_VERSION_INT(55, 10, 100))
>>
>> This is wrong. With this check, FF_API_CRC_BIG_TABLE is false. The point
>> of these FF_API defines is to make sure they are true until the next major
>> bump. That's why you use LIBAVUTIL_VERSION_MAJOR < 56, like it's being
>> done for the rest.
> 
> Finally getting a sense for these things, thanks. Barring that, does
> it look fine?

Yes. You can also skip bumping minor. You're scheduling a change for the next
major bump and not making any changes with immediate effects, so a minor bump
is not necessary.

> 
>>
>>> +#endif
>>>
>>>
>>>  /**
>>>
>>
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