| /* | |
| * Copyright (c) 2002 Michael Niedermayer <[email protected]> | |
| * | |
| * 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 | |
| * simple arithmetic expression evaluator | |
| */ | |
| typedef struct AVExpr AVExpr; | |
| /** | |
| * Parse and evaluate an expression. | |
| * Note, this is significantly slower than av_expr_eval(). | |
| * | |
| * @param res a pointer to a double where is put the result value of | |
| * the expression, or NAN in case of error | |
| * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" | |
| * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} | |
| * @param const_values a zero terminated array of values for the identifiers from const_names | |
| * @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers | |
| * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument | |
| * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers | |
| * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments | |
| * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 | |
| * @param log_offset log level offset, can be used to silence error messages | |
| * @param log_ctx parent logging context | |
| * @return >= 0 in case of success, a negative value corresponding to an | |
| * AVERROR code otherwise | |
| */ | |
| int av_expr_parse_and_eval(double *res, const char *s, | |
| const char * const *const_names, const double *const_values, | |
| const char * const *func1_names, double (* const *funcs1)(void *, double), | |
| const char * const *func2_names, double (* const *funcs2)(void *, double, double), | |
| void *opaque, int log_offset, void *log_ctx); | |
| /** | |
| * Parse an expression. | |
| * | |
| * @param expr a pointer where is put an AVExpr containing the parsed | |
| * value in case of successful parsing, or NULL otherwise. | |
| * The pointed to AVExpr must be freed with av_expr_free() by the user | |
| * when it is not needed anymore. | |
| * @param s expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)" | |
| * @param const_names NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0} | |
| * @param func1_names NULL terminated array of zero terminated strings of funcs1 identifiers | |
| * @param funcs1 NULL terminated array of function pointers for functions which take 1 argument | |
| * @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers | |
| * @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments | |
| * @param log_offset log level offset, can be used to silence error messages | |
| * @param log_ctx parent logging context | |
| * @return >= 0 in case of success, a negative value corresponding to an | |
| * AVERROR code otherwise | |
| */ | |
| int av_expr_parse(AVExpr **expr, const char *s, | |
| const char * const *const_names, | |
| const char * const *func1_names, double (* const *funcs1)(void *, double), | |
| const char * const *func2_names, double (* const *funcs2)(void *, double, double), | |
| int log_offset, void *log_ctx); | |
| /** | |
| * Evaluate a previously parsed expression. | |
| * | |
| * @param e the AVExpr to evaluate | |
| * @param const_values a zero terminated array of values for the identifiers from av_expr_parse() const_names | |
| * @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 | |
| * @return the value of the expression | |
| */ | |
| double av_expr_eval(AVExpr *e, const double *const_values, void *opaque); | |
| /** | |
| * Track the presence of variables and their number of occurrences in a parsed expression | |
| * | |
| * @param e the AVExpr to track variables in | |
| * @param counter a zero-initialized array where the count of each variable will be stored | |
| * @param size size of array | |
| * @return 0 on success, a negative value indicates that no expression or array was passed | |
| * or size was zero | |
| */ | |
| int av_expr_count_vars(AVExpr *e, unsigned *counter, int size); | |
| /** | |
| * Track the presence of user provided functions and their number of occurrences | |
| * in a parsed expression. | |
| * | |
| * @param e the AVExpr to track user provided functions in | |
| * @param counter a zero-initialized array where the count of each function will be stored | |
| * if you passed 5 functions with 2 arguments to av_expr_parse() | |
| * then for arg=2 this will use upto 5 entries. | |
| * @param size size of array | |
| * @param arg number of arguments the counted functions have | |
| * @return 0 on success, a negative value indicates that no expression or array was passed | |
| * or size was zero | |
| */ | |
| int av_expr_count_func(AVExpr *e, unsigned *counter, int size, int arg); | |
| /** | |
| * Free a parsed expression previously created with av_expr_parse(). | |
| */ | |
| void av_expr_free(AVExpr *e); | |
| /** | |
| * Parse the string in numstr and return 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 by | |
| * 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); | |