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  1. /*
  2.  * copyright (c) 2005-2012 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 "attributes.h"
  27. #include "rational.h"
  28. #include "intfloat.h"
  29.  
  30. #ifndef M_E
  31. #define M_E            2.7182818284590452354   /* e */
  32. #endif
  33. #ifndef M_LN2
  34. #define M_LN2          0.69314718055994530942  /* log_e 2 */
  35. #endif
  36. #ifndef M_LN10
  37. #define M_LN10         2.30258509299404568402  /* log_e 10 */
  38. #endif
  39. #ifndef M_LOG2_10
  40. #define M_LOG2_10      3.32192809488736234787  /* log_2 10 */
  41. #endif
  42. #ifndef M_PHI
  43. #define M_PHI          1.61803398874989484820   /* phi / golden ratio */
  44. #endif
  45. #ifndef M_PI
  46. #define M_PI           3.14159265358979323846  /* pi */
  47. #endif
  48. #ifndef M_SQRT1_2
  49. #define M_SQRT1_2      0.70710678118654752440  /* 1/sqrt(2) */
  50. #endif
  51. #ifndef M_SQRT2
  52. #define M_SQRT2        1.41421356237309504880  /* sqrt(2) */
  53. #endif
  54. #ifndef NAN
  55. #define NAN            av_int2float(0x7fc00000)
  56. #endif
  57. #ifndef INFINITY
  58. #define INFINITY       av_int2float(0x7f800000)
  59. #endif
  60.  
  61. /**
  62.  * @addtogroup lavu_math
  63.  * @{
  64.  */
  65.  
  66.  
  67. enum AVRounding {
  68.     AV_ROUND_ZERO     = 0, ///< Round toward zero.
  69.     AV_ROUND_INF      = 1, ///< Round away from zero.
  70.     AV_ROUND_DOWN     = 2, ///< Round toward -infinity.
  71.     AV_ROUND_UP       = 3, ///< Round toward +infinity.
  72.     AV_ROUND_NEAR_INF = 5, ///< Round to nearest and halfway cases away from zero.
  73.     AV_ROUND_PASS_MINMAX = 8192, ///< Flag to pass INT64_MIN/MAX through instead of rescaling, this avoids special cases for AV_NOPTS_VALUE
  74. };
  75.  
  76. /**
  77.  * Return the greatest common divisor of a and b.
  78.  * If both a and b are 0 or either or both are <0 then behavior is
  79.  * undefined.
  80.  */
  81. int64_t av_const av_gcd(int64_t a, int64_t b);
  82.  
  83. /**
  84.  * Rescale a 64-bit integer with rounding to nearest.
  85.  * A simple a*b/c isn't possible as it can overflow.
  86.  */
  87. int64_t av_rescale(int64_t a, int64_t b, int64_t c) av_const;
  88.  
  89. /**
  90.  * Rescale a 64-bit integer with specified rounding.
  91.  * A simple a*b/c isn't possible as it can overflow.
  92.  *
  93.  * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
  94.  *         INT64_MIN or INT64_MAX then a is passed through unchanged.
  95.  */
  96. int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding) av_const;
  97.  
  98. /**
  99.  * Rescale a 64-bit integer by 2 rational numbers.
  100.  */
  101. int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
  102.  
  103. /**
  104.  * Rescale a 64-bit integer by 2 rational numbers with specified rounding.
  105.  *
  106.  * @return rescaled value a, or if AV_ROUND_PASS_MINMAX is set and a is
  107.  *         INT64_MIN or INT64_MAX then a is passed through unchanged.
  108.  */
  109. int64_t av_rescale_q_rnd(int64_t a, AVRational bq, AVRational cq,
  110.                          enum AVRounding) av_const;
  111.  
  112. /**
  113.  * Compare 2 timestamps each in its own timebases.
  114.  * The result of the function is undefined if one of the timestamps
  115.  * is outside the int64_t range when represented in the others timebase.
  116.  * @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
  117.  */
  118. int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
  119.  
  120. /**
  121.  * Compare 2 integers modulo mod.
  122.  * That is we compare integers a and b for which only the least
  123.  * significant log2(mod) bits are known.
  124.  *
  125.  * @param mod must be a power of 2
  126.  * @return a negative value if a is smaller than b
  127.  *         a positive value if a is greater than b
  128.  *         0                if a equals          b
  129.  */
  130. int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
  131.  
  132. /**
  133.  * Rescale a timestamp while preserving known durations.
  134.  *
  135.  * @param in_ts Input timestamp
  136.  * @param in_tb Input timesbase
  137.  * @param fs_tb Duration and *last timebase
  138.  * @param duration duration till the next call
  139.  * @param out_tb Output timesbase
  140.  */
  141. int64_t av_rescale_delta(AVRational in_tb, int64_t in_ts,  AVRational fs_tb, int duration, int64_t *last, AVRational out_tb);
  142.  
  143. /**
  144.  * @}
  145.  */
  146.  
  147. #endif /* AVUTIL_MATHEMATICS_H */
  148.