mathematics.h
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上传日期:2022-07-11
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- /*
- * copyright (c) 2005 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
- */
- #ifndef AVUTIL_MATHEMATICS_H
- #define AVUTIL_MATHEMATICS_H
- //#include <stdint.h>
- #include <math.h>
- #include "rational.h"
- #ifndef M_E
- #define M_E 2.7182818284590452354 /* e */
- #endif
- #ifndef M_LN2
- #define M_LN2 0.69314718055994530942 /* log_e 2 */
- #endif
- #ifndef M_LN10
- #define M_LN10 2.30258509299404568402 /* log_e 10 */
- #endif
- #ifndef M_PI
- #define M_PI 3.14159265358979323846 /* pi */
- #endif
- #ifndef M_SQRT1_2
- #define M_SQRT1_2 0.70710678118654752440 /* 1/sqrt(2) */
- #endif
- 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
- };
- /**
- * rescale a 64bit 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 64bit 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 64bit integer by 2 rational numbers.
- */
- int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
- #endif /* AVUTIL_MATHEMATICS_H */