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(*
* Rational numbers
* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*)
(* This is a part of Pascal porting of ffmpeg.
* Originally by Victor Zinetz for Delphi and Free Pascal on Windows.
* For Mac OS X, some modifications were made by The Creative CAT, denoted as CAT
* in the source codes *)
(*
* Conversion of libavutil/rational.h
* revision 12498, Wed Mar 19 06:17:43 2008 UTC
*)
unit rational;
{$IFDEF FPC}
{$MODE DELPHI}
{$PACKENUM 4} (* use 4-byte enums *)
{$PACKRECORDS C} (* C/C++-compatible record packing *)
{$ELSE}
{$MINENUMSIZE 4} (* use 4-byte enums *)
{$ENDIF}
{$I switches.inc}
interface
uses
UConfig;
type
(*
* Rational number num/den.
*)
PAVRational = ^TAVRational;
TAVRational = record
num: integer; ///< numerator
den: integer; ///< denominator
end;
(**
* Compare two rationals.
* @param a first rational
* @param b second rational
* @return 0 if a==b, 1 if a>b and -1 if a<b.
*)
function av_cmp_q(a: TAVRational; b: TAVRational): integer; {$IFDEF HasInline}inline;{$ENDIF}
(**
* Rational to double conversion.
* @param a rational to convert
* @return (double) a
*)
function av_q2d(a: TAVRational): double; {$IFDEF HasInline}inline;{$ENDIF}
(**
* Reduce a fraction.
* This is useful for framerate calculations.
* @param dst_nom destination numerator
* @param dst_den destination denominator
* @param nom source numerator
* @param den source denominator
* @param max the maximum allowed for dst_nom & dst_den
* @return 1 if exact, 0 otherwise
*)
function av_reduce(dst_nom: PInteger; dst_den: PInteger; nom: int64; den: int64; max: int64): integer;
cdecl; external av__util;
(**
* Multiplies two rationals.
* @param b first rational.
* @param c second rational.
* @return b*c.
*)
function av_mul_q(b: TAVRational; c: TAVRational): TAVRational;
cdecl; external av__util; {av_const}
(**
* Divides one rational by another.
* @param b first rational.
* @param c second rational.
* @return b/c.
*)
function av_div_q(b: TAVRational; c: TAVRational): TAVRational;
cdecl; external av__util; {av_const}
(**
* Adds two rationals.
* @param b first rational.
* @param c second rational.
* @return b+c.
*)
function av_add_q(b: TAVRational; c: TAVRational): TAVRational;
cdecl; external av__util; {av_const}
(**
* Subtracts one rational from another.
* @param b first rational.
* @param c second rational.
* @return b-c.
*)
function av_sub_q(b: TAVRational; c: TAVRational): TAVRational;
cdecl; external av__util; {av_const}
(**
* Converts a double precision floating point number to a rational.
* @param d double to convert
* @param max the maximum allowed numerator and denominator
* @return (AVRational) d.
*)
function av_d2q(d: double; max: integer): TAVRational;
cdecl; external av__util; {av_const}
implementation
function av_cmp_q (a: TAVRational; b: TAVRational): integer;
var
tmp: int64;
begin
tmp := a.num * int64(b.den) - b.num * int64(a.den);
if (tmp <> 0) then
Result := (tmp shr 63) or 1
else
Result := 0
end;
function av_q2d(a: TAVRational): double;
begin
Result := a.num / a.den;
end;
end.
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