libavcodec/eval.h

   1 /*
   2  * simple arithmetic expression evaluator
   3  *
   4  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 /**
  24  * @file eval.h
  25  * eval header.
  26  */
  27
  28 #ifndef FFMPEG_EVAL_H
  29 #define FFMPEG_EVAL_H
  30
  31 #if LIBAVCODEC_VERSION_INT < ((52<<16)+(0<<8)+0)
  32 /**
  33  * @deprecated Use ff_eval2 instead
  34  */
  35 double ff_eval(char *s, double *const_value, const char **const_name,
  36                double (**func1)(void *, double), const char **func1_name,
  37                double (**func2)(void *, double, double), char **func2_name,
  38                void *opaque);
  39 #endif
  40
  41 /**
  42  * Parses and evaluates an expression.
  43  * Note, this is significantly slower than ff_parse_eval()
  44  * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)"
  45  * @param func1 NULL terminated array of function pointers for functions which take 1 argument
  46  * @param func2 NULL terminated array of function pointers for functions which take 2 arguments
  47  * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0}
  48  * @param func1_name NULL terminated array of zero terminated strings of func1 identifers
  49  * @param func2_name NULL terminated array of zero terminated strings of func2 identifers
  50  * @param error pointer to a char* which is set to an error message if something goes wrong
  51  * @param const_value a zero terminated array of values for the identifers from const_name
  52  * @param opaque a pointer which will be passed to all functions from func1 and func2
  53  * @return the value of the expression
  54  */
  55 double ff_eval2(const char *s, double *const_value, const char **const_name,
  56                double (**func1)(void *, double), const char **func1_name,
  57                double (**func2)(void *, double, double), char **func2_name,
  58                void *opaque, const char **error);
  59
  60 typedef struct ff_expr_s AVEvalExpr;
  61
  62 /**
  63  * Parses a expression.
  64  * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)"
  65  * @param func1 NULL terminated array of function pointers for functions which take 1 argument
  66  * @param func2 NULL terminated array of function pointers for functions which take 2 arguments
  67  * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0}
  68  * @param func1_name NULL terminated array of zero terminated strings of func1 identifers
  69  * @param func2_name NULL terminated array of zero terminated strings of func2 identifers
  70  * @param error pointer to a char* which is set to an error message if something goes wrong
  71  * @return AVEvalExpr which must be freed with ff_eval_free by the user when it is not needed anymore
  72  *         NULL if anything went wrong
  73  */
  74 AVEvalExpr * ff_parse(const char *s, const char **const_name,
  75                double (**func1)(void *, double), const char **func1_name,
  76                double (**func2)(void *, double, double), char **func2_name,
  77                const char **error);
  78 /**
  79  * Evaluates a previously parsed expression.
  80  * @param const_value a zero terminated array of values for the identifers from ff_parse const_name
  81  * @param opaque a pointer which will be passed to all functions from func1 and func2
  82  * @return the value of the expression
  83  */
  84 double ff_parse_eval(AVEvalExpr * e, double *const_value, void *opaque);
  85 void ff_eval_free(AVEvalExpr * e);
  86
  87 #endif /* FFMPEG_EVAL_H */