libavutil/integer.h

   1 /*
   2  * arbitrary precision integers
   3  * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file integer.h
  24  * arbitrary precision integers
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #ifndef AVUTIL_INTEGER_H
  29 #define AVUTIL_INTEGER_H
  30
  31 #include <stdint.h>
  32 #include "common.h"
  33
  34 #define AV_INTEGER_SIZE 8
  35
  36 typedef struct AVInteger{
  37     uint16_t v[AV_INTEGER_SIZE];
  38 } AVInteger;
  39
  40 AVInteger av_add_i(AVInteger a, AVInteger b) av_const;
  41 AVInteger av_sub_i(AVInteger a, AVInteger b) av_const;
  42
  43 /**
  44  * returns the rounded down value of the logarithm of base 2 of the given AVInteger.
  45  * this is simply the index of the most significant bit which is 1. Or 0 of all bits are 0
  46  */
  47 int av_log2_i(AVInteger a) av_const;
  48 AVInteger av_mul_i(AVInteger a, AVInteger b) av_const;
  49
  50 /**
  51  * returns 0 if a==b, 1 if a>b and -1 if a<b.
  52  */
  53 int av_cmp_i(AVInteger a, AVInteger b) av_const;
  54
  55 /**
  56  * bitwise shift.
  57  * @param s the number of bits by which the value should be shifted right, may be negative for shifting left
  58  */
  59 AVInteger av_shr_i(AVInteger a, int s) av_const;
  60
  61 /**
  62  * returns a % b.
  63  * @param quot a/b will be stored here
  64  */
  65 AVInteger av_mod_i(AVInteger *quot, AVInteger a, AVInteger b);
  66
  67 /**
  68  * returns a/b.
  69  */
  70 AVInteger av_div_i(AVInteger a, AVInteger b) av_const;
  71
  72 /**
  73  * converts the given int64_t to an AVInteger.
  74  */
  75 AVInteger av_int2i(int64_t a) av_const;
  76
  77 /**
  78  * converts the given AVInteger to an int64_t.
  79  * if the AVInteger is too large to fit into an int64_t,
  80  * then only the least significant 64bit will be used
  81  */
  82 int64_t av_i2int(AVInteger a) av_const;
  83
  84 #endif /* AVUTIL_INTEGER_H */