| /* |
| * 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 |
| * simple arithmetic expression evaluator |
| */ |
| |
| #ifndef AVUTIL_EVAL_H |
| #define AVUTIL_EVAL_H |
| |
| #include "avutil.h" |
| |
| 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_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_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 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 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 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); |
| |
| #endif /* AVUTIL_EVAL_H */ |