/* * simple arithmetic expression evaluator * * Copyright (c) 2002 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 */ /** * @file libavcodec/eval.h * eval header. */ #ifndef AVCODEC_EVAL_H #define AVCODEC_EVAL_H /** * Parses and evaluates an expression. * Note, this is significantly slower than ff_parse_eval() * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)" * @param func1 NULL terminated array of function pointers for functions which take 1 argument * @param func2 NULL terminated array of function pointers for functions which take 2 arguments * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0} * @param func1_name NULL terminated array of zero terminated strings of func1 identifers * @param func2_name NULL terminated array of zero terminated strings of func2 identifers * @param error pointer to a char* which is set to an error message if something goes wrong * @param const_value a zero terminated array of values for the identifers from const_name * @param opaque a pointer which will be passed to all functions from func1 and func2 * @return the value of the expression */ double ff_eval2(const char *s, const double *const_value, const char * const *const_name, double (**func1)(void *, double), const char **func1_name, double (**func2)(void *, double, double), const char **func2_name, void *opaque, const char **error); typedef struct ff_expr_s AVEvalExpr; /** * Parses a expression. * @param s expression as a zero terminated string for example "1+2^3+5*5+sin(2/3)" * @param func1 NULL terminated array of function pointers for functions which take 1 argument * @param func2 NULL terminated array of function pointers for functions which take 2 arguments * @param const_name NULL terminated array of zero terminated strings of constant identifers for example {"PI", "E", 0} * @param func1_name NULL terminated array of zero terminated strings of func1 identifers * @param func2_name NULL terminated array of zero terminated strings of func2 identifers * @param error pointer to a char* which is set to an error message if something goes wrong * @return AVEvalExpr which must be freed with ff_eval_free by the user when it is not needed anymore * NULL if anything went wrong */ AVEvalExpr * ff_parse(const char *s, const char * const *const_name, double (**func1)(void *, double), const char **func1_name, double (**func2)(void *, double, double), const char **func2_name, const char **error); /** * Evaluates a previously parsed expression. * @param const_value a zero terminated array of values for the identifers from ff_parse const_name * @param opaque a pointer which will be passed to all functions from func1 and func2 * @return the value of the expression */ double ff_parse_eval(AVEvalExpr * e, const double *const_value, void *opaque); void ff_eval_free(AVEvalExpr * e); #endif /* AVCODEC_EVAL_H */