/* * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef AVUTIL_MATHEMATICS_H #define AVUTIL_MATHEMATICS_H #include <stdint.h> #include <math.h> #include "attributes.h" #include "rational.h" #include "intfloat.h" #ifndef M_LOG2_10 #define M_LOG2_10 3.32192809488736234787 /* log_2 10 */ #endif #ifndef M_PHI #define M_PHI 1.61803398874989484820 /* phi / golden ratio */ #endif #ifndef NAN #define NAN av_int2float(0x7fc00000) #endif #ifndef INFINITY #define INFINITY av_int2float(0x7f800000) #endif /** * @addtogroup lavu_math * @{ */ enum AVRounding { 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. }; /** * 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. */ 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; /** * Rescale a 64-bit integer by 2 rational numbers with specified rounding. */ 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); /** * @} */ #endif /* AVUTIL_MATHEMATICS_H */