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/*
* 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);
/**
* Parses the string in numstr and returns its value as a double. If
* the string is empty, contains only whitespaces, or does not contain
* an initial substring that has the expected syntax for a
* floating-point number, no conversion is performed. In this case,
* returns a value of zero and the value returned in tail is the value
* of numstr.
*
* @param numstr a string representing a number, may contain one of
* the International System number postfixes, for example 'K', 'M',
* 'G'. If 'i' is appended after the postfix, powers of 2 are used
* instead of powers of 10. The 'B' postfix multiplies the value for
* 8, and can be appended after another postfix or used alone. This
* allows using for example 'KB', 'MiB', 'G' and 'B' as postfix.
* @param tail if non-NULL puts here the pointer to the char next
* after the last parsed character
*/
double av_strtod(const char *numstr, char **tail);
#endif /* AVCODEC_EVAL_H */
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