[FFmpeg-devel] [PATCH] do not memset for a size of 0

Benoit Fouet benoit.fouet
Mon Oct 12 18:34:33 CEST 2009


On 2009-10-12 18:26, Reimar D?ffinger wrote:
> On Mon, Oct 12, 2009 at 05:20:15PM +0200, Benoit Fouet wrote:
>> Hi,
>>
>> the following patch fixes the linker warning:
>> /home/hack/ffmpeg/ffmpeg_x86/libavcodec/libavcodec.a(pcx.o): In function
>> `memset':
>>
>>
>> /usr/include/bits/string3.h:82: warning: memset used with constant zero
>> length parameter; this could be due to transposed parameters
>>
>> Index: libavcodec/pcx.c
>> ===================================================================
>> --- libavcodec/pcx.c    (revision 20209)
>> +++ libavcodec/pcx.c    (working copy)
>> @@ -71,6 +71,7 @@ static void pcx_palette(const uint8_t **
>>
>>      for (i=0; i<pallen; i++)
>>          *dst++ = bytestream_get_be24(src);
>> +    if (256 - pallen)
>>      memset(dst, 0, (256 - pallen) * sizeof(*dst));
>>  }
> 
> I think it is a good idea, but
> if (pallen < 256)
> IMO is more readable.

indeed :)

Index: pcx.c
===================================================================
--- pcx.c	(revision 20209)
+++ pcx.c	(working copy)
@@ -71,6 +71,7 @@ static void pcx_palette(const uint8_t **

     for (i=0; i<pallen; i++)
         *dst++ = bytestream_get_be24(src);
+    if (pallen < 256)
     memset(dst, 0, (256 - pallen) * sizeof(*dst));
 }


Ben




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