libavutil/eval.h File Reference

simple arithmetic expression evaluator More...

#include "avutil.h"

Go to the source code of this file.

Typedefs
typedef struct AVExpr	AVExpr
Functions
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 and evaluate an expression.
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)
	Parse an expression.
double	av_expr_eval (AVExpr *e, const double *const_values, void *opaque)
	Evaluate a previously parsed expression.
void	av_expr_free (AVExpr *e)
	Free a parsed expression previously created with av_expr_parse().
attribute_deprecated int	av_parse_and_eval_expr (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)
attribute_deprecated int	av_parse_expr (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)
attribute_deprecated double	av_eval_expr (AVExpr *e, const double *const_values, void *opaque)
attribute_deprecated void	av_free_expr (AVExpr *e)
double	av_strtod (const char *numstr, char **tail)
	Parse the string in numstr and return its value as a double.

---

Detailed Description

simple arithmetic expression evaluator

Definition in file eval.h.

---

Typedef Documentation

typedef struct AVExpr AVExpr

Definition at line 31 of file eval.h.

---

Function Documentation

attribute_deprecated double av_eval_expr	(	AVExpr *	e,
		const double *	const_values,
		void *	opaque
	)

Deprecated:

Deprecated in favor of av_expr_eval().

Definition at line 556 of file eval.c.

double av_expr_eval	(	AVExpr *	e,
		const double *	const_values,
		void *	opaque
	)

Evaluate a previously parsed expression.

Parameters:

	const_values	a zero terminated array of values for the identifiers from av_expr_parse() const_names
	opaque	a pointer which will be passed to all functions from funcs1 and funcs2

Returns:

the value of the expression

Definition at line 518 of file eval.c.

Referenced by av_eval_expr(), av_expr_parse_and_eval(), config_props(), get_qscale(), put_image(), select_frame(), and start_frame().

void av_expr_free

(

AVExpr *

e

)

Free a parsed expression previously created with av_expr_parse().

Definition at line 187 of file eval.c.

Referenced by av_expr_free(), av_expr_parse(), av_expr_parse_and_eval(), av_free_expr(), ff_rate_control_uninit(), parse_expr(), parse_factor(), parse_primary(), parse_subexpr(), parse_term(), and uninit().

int av_expr_parse	(	AVExpr **	expr,
		const char *	s,
		const char *const *	const_names,
		const char *const *	func1_names,
		double(**)(void *, double)	funcs1,
		const char *const *	func2_names,
		double(**)(void *, double, double)	funcs2,
		int	log_offset,
		void *	log_ctx
	)

Parse an expression.

Parameters:

	expr	a pointer where is put an AVExpr containing the parsed value in case of successfull parsing, or NULL otherwise. The pointed to AVExpr must be freed with av_expr_free() by the user when it is not needed anymore.
	s	expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
	const_names	NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
	func1_names	NULL terminated array of zero terminated strings of funcs1 identifiers
	funcs1	NULL terminated array of function pointers for functions which take 1 argument
	func2_names	NULL terminated array of zero terminated strings of funcs2 identifiers
	funcs2	NULL terminated array of function pointers for functions which take 2 arguments
	log_ctx	parent logging context

Returns:

0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 468 of file eval.c.

Referenced by av_expr_parse_and_eval(), av_parse_expr(), config_input(), config_props(), ff_rate_control_init(), init(), and vf_open().

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(**)(void *, double)	funcs1,
		const char *const *	func2_names,
		double(**)(void *, double, double)	funcs2,
		void *	opaque,
		int	log_offset,
		void *	log_ctx
	)

Parse and evaluate an expression.

Note, this is significantly slower than av_expr_eval().

Parameters:

	res	a pointer to a double where is put the result value of the expression, or NAN in case of error
	s	expression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
	const_names	NULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
	const_values	a zero terminated array of values for the identifiers from const_names
	func1_names	NULL terminated array of zero terminated strings of funcs1 identifiers
	funcs1	NULL terminated array of function pointers for functions which take 1 argument
	func2_names	NULL terminated array of zero terminated strings of funcs2 identifiers
	funcs2	NULL terminated array of function pointers for functions which take 2 arguments
	opaque	a pointer which will be passed to all functions from funcs1 and funcs2
	log_ctx	parent logging context

Returns:

0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 527 of file eval.c.

Referenced by av_parse_and_eval_expr(), av_parse_video_rate(), av_set_string3(), config(), config_input(), config_input_overlay(), config_output_props(), and config_props().

attribute_deprecated void av_free_expr

(

AVExpr *

e

)

Deprecated:

Deprecated in favor of av_expr_free().

Definition at line 571 of file eval.c.

attribute_deprecated int av_parse_and_eval_expr	(	double *	res,
		const char *	s,
		const char *const *	const_names,
		const double *	const_values,
		const char *const *	func1_names,
		double(**)(void *, double)	funcs1,
		const char *const *	func2_names,
		double(**)(void *, double, double)	funcs2,
		void *	opaque,
		int	log_offset,
		void *	log_ctx
	)

Deprecated:

Deprecated in favor of av_expr_parse_and_eval().

Definition at line 561 of file eval.c.

attribute_deprecated int av_parse_expr	(	AVExpr **	expr,
		const char *	s,
		const char *const *	const_names,
		const char *const *	func1_names,
		double(**)(void *, double)	funcs1,
		const char *const *	func2_names,
		double(**)(void *, double, double)	funcs2,
		int	log_offset,
		void *	log_ctx
	)

Deprecated:

Deprecated in favor of av_expr_parse().

Definition at line 546 of file eval.c.

double av_strtod	(	const char *	numstr,
		char **	tail
	)

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.

Parameters:

	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.
	tail	if non-NULL puts here the pointer to the char next after the last parsed character

Definition at line 74 of file eval.c.

Referenced by parse_number_or_die(), and parse_primary().