(*
  * copyright (c) 2005-2012 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg 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 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*)

unit mathematics;

{$include ffmpeg.inc}

interface

uses
  rational;

{$IFNDEF M_E}

const
  M_E = 2.7182818284590452354; (* e *)
{$ENDIF}
{$IFNDEF M_LN2}

const
  M_LN2 = 0.69314718055994530942; (* log_e 2 *)
{$ENDIF}
{$IFNDEF M_LN10}

const
  M_LN10 = 2.30258509299404568402; (* log_e 10 *)
{$ENDIF}
{$IFNDEF M_LOG2_10}

const
  M_LOG2_10 = 3.32192809488736234787; (* log_2 10 *)
{$ENDIF}
{$IFNDEF M_PHI}

const
  M_PHI = 1.61803398874989484820; (* phi / golden ratio *)
{$ENDIF}
{$IFNDEF M_PI}

const
  M_PI = 3.14159265358979323846; (* pi *)
{$ENDIF}
{$IFNDEF M_SQRT1_2}

const
  M_SQRT1_2 = 0.70710678118654752440; (* 1/sqrt(2) *)
{$ENDIF}
{$IFNDEF M_SQRT2}

const
  M_SQRT2 = 1.41421356237309504880; (* sqrt(2) *)
{$ENDIF}
{$IFNDEF NAN}

const
  NAN = $7FC00000;
{$ENDIF}
{$IFNDEF INFINITY}

const
  INFINITY = $7F800000;
{$ENDIF}

Type
  TAVRounding = (AV_ROUND_ZERO = 0,
    /// < Round toward zero.
    AV_ROUND_INF = 1,
    /// < Round away from zero.
    AV_ROUND_DOWN = 2,
    /// < Round toward -infinity.
    AV_ROUND_UP = 3,
    /// < Round toward +infinity.
    AV_ROUND_NEAR_INF = 5,
    /// < Round to nearest and halfway cases away from zero.
    AV_ROUND_PASS_MINMAX = 8192
    /// < Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE
    );

  (*
    * Return the greatest common divisor of a and b.
    * If both a and b are 0 or either or both are <0 then behavior is
    * undefined.
  *)
  // int64_t av_const av_gcd(int64_t a, int64_t b);

  (*
    * Rescale a 64-bit integer with rounding to nearest.
    * A simple a*b/c isn't possible as it can overflow.
  *)
  // int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;

  (*
    * Rescale a 64-bit integer with specified rounding.
    * A simple a*b/c isn't possible as it can overflow.
    *
    * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
    *         INT64_MIN or INT64_MAX then a is passed through unchanged.
  *)
  // int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;

  (*
    * Rescale a 64-bit integer by 2 rational numbers.
  *)
  // int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
function av_rescale_q(a: int64; bq: TAVRational; cq: TAVRational): int64; cdecl;

(*
  * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
  *
  * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
  *         INT64_MIN or INT64_MAX then a is passed through unchanged.
*)
// int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq, enum AVRounding)av_const;

(*
  * Compare 2 timestamps each in its own timebases.
  * The result of the function is undefined if one of the timestamps
  * is outside the int64_t range when represented in the others timebase.
  * @return -1 if ts_a is before ts_b, 1 if ts_a is after ts_b or 0 if they represent the same position
*)
// int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);

(*
  * Compare 2 integers modulo mod.
  * That is we compare integers a and b for which only the least
  * significant log2(mod) bits are known.
  *
  * @param mod must be a power of 2
  * @return a negative value if a is smaller than b
  *         a positive value if a is greater than b
  *         0                if a equals          b
*)
// int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);

(*
  * Rescale a timestamp while preserving known durations.
  *
  * @param in_ts Input timestamp
  * @param in_tb Input timesbase
  * @param fs_tb Duration and *last timebase
  * @param duration duration till the next call
  * @param out_tb Output timesbase
*)
// int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts, AVRational fs_tb, int duration, int64_t * last, AVRational out_tb);

implementation

uses ffmpeglib;

function av_rescale_q; external avutil_dll;

end.