libavutil/mathematics.h

   1 /*
   2  * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef AVUTIL_MATHEMATICS_H
  22 #define AVUTIL_MATHEMATICS_H
  23
  24 #include <stdint.h>
  25 #include <math.h>
  26 #include "common.h"
  27 #include "rational.h"
  28
  29 #ifndef M_E
  30 #define M_E            2.7182818284590452354   /* e */
  31 #endif
  32 #ifndef M_LN2
  33 #define M_LN2          0.69314718055994530942  /* log_e 2 */
  34 #endif
  35 #ifndef M_LN10
  36 #define M_LN10         2.30258509299404568402  /* log_e 10 */
  37 #endif
  38 #ifndef M_PI
  39 #define M_PI           3.14159265358979323846  /* pi */
  40 #endif
  41 #ifndef M_SQRT1_2
  42 #define M_SQRT1_2      0.70710678118654752440  /* 1/sqrt(2) */
  43 #endif
  44 #ifndef NAN
  45 #define NAN            (0.0/0.0)
  46 #endif
  47 #ifndef INFINITY
  48 #define INFINITY       (1.0/0.0)
  49 #endif
  50
  51 enum AVRounding {
  52     AV_ROUND_ZERO     = 0, ///< Round toward zero.
  53     AV_ROUND_INF      = 1, ///< Round away from zero.
  54     AV_ROUND_DOWN     = 2, ///< Round toward -infinity.
  55     AV_ROUND_UP       = 3, ///< Round toward +infinity.
  56     AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
  57 };
  58
  59 int64_t av_const av_gcd(int64_t a, int64_t b);
  60
  61 /**
  62  * Rescales a 64-bit integer with rounding to nearest.
  63  * A simple a*b/c isn't possible as it can overflow.
  64  */
  65 int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
  66
  67 /**
  68  * Rescales a 64-bit integer with specified rounding.
  69  * A simple a*b/c isn't possible as it can overflow.
  70  */
  71 int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
  72
  73 /**
  74  * Rescales a 64-bit integer by 2 rational numbers.
  75  */
  76 int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
  77
  78 #endif /* AVUTIL_MATHEMATICS_H */