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/*
* Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
* |
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* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* 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 |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/** |
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* @file |
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* simple arithmetic expression evaluator |
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*/
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#ifndef AVUTIL_EVAL_H
#define AVUTIL_EVAL_H |
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#include "avutil.h"
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typedef struct AVExpr AVExpr; |
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/** |
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* Parse and evaluate an expression. |
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* Note, this is significantly slower than av_expr_eval(). |
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* |
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* @param res a pointer to a double where is put the result value of
* the expression, or NAN in case of error |
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* @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 |
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* @param funcs1 NULL terminated array of function pointers for functions which take 1 argument |
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* @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers |
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* @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 |
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* @param log_ctx parent logging context |
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* @return >= 0 in case of success, a negative value corresponding to an |
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* AVERROR code otherwise |
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*/ |
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int av_expr_parse_and_eval(double *res, const char *s, |
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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), |
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void *opaque, int log_offset, void *log_ctx); |
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|
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/** |
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* Parse an expression. |
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* |
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* @param expr a pointer where is put an AVExpr containing the parsed |
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* value in case of successful parsing, or NULL otherwise. |
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* The pointed to AVExpr must be freed with av_expr_free() by the user |
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* when it is not needed anymore. |
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* @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 |
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* @param funcs1 NULL terminated array of function pointers for functions which take 1 argument |
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* @param func2_names NULL terminated array of zero terminated strings of funcs2 identifiers |
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* @param funcs2 NULL terminated array of function pointers for functions which take 2 arguments |
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* @param log_ctx parent logging context |
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* @return >= 0 in case of success, a negative value corresponding to an |
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* AVERROR code otherwise |
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*/ |
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int av_expr_parse(AVExpr **expr, const char *s, |
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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), |
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int log_offset, void *log_ctx); |
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|
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/** |
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* Evaluate a previously parsed expression. |
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* |
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* @param const_values a zero terminated array of values for the identifiers from av_expr_parse() const_names |
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* @param opaque a pointer which will be passed to all functions from funcs1 and funcs2 |
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* @return the value of the expression
*/ |
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double av_expr_eval(AVExpr *e, const double *const_values, void *opaque);
/**
* Free a parsed expression previously created with av_expr_parse().
*/
void av_expr_free(AVExpr *e);
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/** |
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* Parse the string in numstr and return its value as a double. If |
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* 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 |
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* instead of powers of 10. The 'B' postfix multiplies the value by |
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* 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 |
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*/
double av_strtod(const char *numstr, char **tail);
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#endif /* AVUTIL_EVAL_H */ |