0,0 → 1,113 |
/* |
* 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" |
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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); |
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/** |
* Free a parsed expression previously created with av_expr_parse(). |
*/ |
void av_expr_free(AVExpr *e); |
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/** |
* 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 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); |
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#endif /* AVUTIL_EVAL_H */ |