av_gcd is now always defined regardless of input. This documents this
change in the "documented API". Two benefits (closely related):
1. The function is robust, and there is no need to worry about INT64_MIN, etc.
2. Clients of av_gcd, like av_reduce, can now be made fully correct. Currently,
av_reduce can trigger undefined behavior if e.g num is INT64_MIN due to
integer overflow in the FFABS. Furthermore, this undefined behavior is
completely undocumented, and could be a fuzzer's paradise. The FFABS was needed in the past as
av_gcd was undefined for negative inputs. In order to make av_reduce
robust, it is essential to guarantee that av_gcd works for all int64_t.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Some compilers, MSVC among them, don't recognize the divisions by
zero as meaning infinity/nan.
These macros should, according to the standard, expand to constant
expressions, but this shouldn't matter for our usage.
Signed-off-by: Martin Storsjö <martin@martin.st>
This reverts commit a2b186a188.
The defines were present for several years, removing
them without a version bump may break API.
(Fixes MPlayer compilation.)
While these defines are not defined by the C standard they are
standardized as X/Open System Interfaces Extension. We use the
appropiate _XOPEN_SOURCE define to make them available. They
seem to be available on all FATE configs since the constants
are used in files where mathematics.h is not included.
This reduces the number of false dependencies on header files and
speeds up compilation.
Originally committed as revision 22407 to svn://svn.ffmpeg.org/ffmpeg/trunk
Consistently apply this rule: the guard name is obtained from the
filename by stripping the leading "lib", converting '/' and '.' to
'_' and uppercasing the resulting name. Guard names in the root
directory have to be prefixed by "FFMPEG_".
Originally committed as revision 15120 to svn://svn.ffmpeg.org/ffmpeg/trunk
Patch by Zuxy Meng: zuxy meng gmail com
Original thread:
[FFmpeg-devel] [PATCH] Pure, const and malloc attributes to libavutil
Date: 03/18/2008 6:09 AM
Originally committed as revision 12489 to svn://svn.ffmpeg.org/ffmpeg/trunk
Ganesh Ajjanagadde
Lou Logan
Matt Oliver
Michael Niedermayer
Clément Bœsch
Ronald S. Bultje
Carl Eugen Hoyos
Janne Grunau
Justin Ruggles
Luca Barbato
Mans Rullgard
Stefano Sabatini
Alex Converse
Benoit Fouet
Diego Biurrun
Aurelien Jacobs
Zuxy Meng
Alexander Strasser