[FFmpeg-devel] [PATCH 5/8] Add eval.texi file.

Víctor Paesa victorpaesa
Mon Nov 1 10:10:00 CET 2010


Hi,

On Mon, Nov 1, 2010 at 00:25, Stefano Sabatini wrote:
> On date Sunday 2010-10-31 23:58:24 +0100, Michael Niedermayer encoded:
>> On Sun, Oct 31, 2010 at 11:38:43PM +0100, Stefano Sabatini wrote:
>> > On date Sunday 2010-10-31 21:53:53 +0100, Michael Niedermayer encoded:
>> > > On Sun, Oct 31, 2010 at 04:04:32PM +0100, Stefano Sabatini wrote:
>> > [...]
>> > > > diff --git a/doc/eval.texi b/doc/eval.texi
>> > > > new file mode 100644
>> > > > index 0000000..b60d7f4
>> > > > --- /dev/null
>> > > > +++ b/doc/eval.texi
>> > > > @@ -0,0 +1,115 @@
>> > > > + at chapter Expression Evaluation
>> > > > + at c man begin EXPRESSION EVALUATION
>> > > > +
>> > > > +When evaluating an expression, FFmpeg uses an internal formula
>> > > > +evaluator, implemeneted through the @file{libavutil/eval.h} interface.
>> > > > +
>> > >
>> > > > +Two expressions @var{expr1} and @var{expr2} can be combined to form
>> > > > +another expression "@var{expr1};@var{expr2}".
>> > > > + at var{expr1} and @var{expr2} are evaluated in turn, and the new
>> > > > +expression evaluates to the value of @var{expr2}.
>> > >
>> > > I really dont think this should be at the begin of the docs
>> >
>> > Changed position.
>>
>> good, i leave further review to the English & docs experts
>
> Fine, I'll wait some days then I'll commit as it is if no one will
> comment.

--- /dev/null
+++ b/doc/eval.texi
@@ -0,0 +1,115 @@
+ at chapter Expression Evaluation
+ at c man begin EXPRESSION EVALUATION
+
+When evaluating an arithemetic expression, FFmpeg uses an internal
+formula evaluator, implemented through the @file{libavutil/eval.h}
+interface.
+
+An expression may contain unary, binary operators, and functions.

"An expression may contain unary, binary operators, constants, and functions."

[...]

+It is possible to define more unary and binary functions used in an
+expression, and define a list of the recognized constants.

"In your C code, you can extend the list of unary and binary functions,
and define recognized constants, so that they are available for your
expressions."

[...]

+The evaluator also recognizes the Internation System number postfixes.

International

+If 'i' is appended after the postfix, powers of 2 are used
+instead of powers of 10. The 'B' postfix multiplies the value for
+8, and can be appended after another postfix or used alone. This
+allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.

Regards,
V?ctor



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