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 701 of file eval.c.

Referenced by av_parse_ratio(), config(), config_input(), config_output_props(), config_props(), func_eval_expr(), init(), main(), and set_string_number().

Parse an expression.

Parameters

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.

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 640 of file eval.c.

Referenced by av_expr_parse_and_eval(), config_input(), config_props(), ff_rate_control_init(), geq_init(), init(), modplug_read_header(), process_command(), set_enable_expr(), set_expr(), and transcode_init().

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 691 of file eval.c.

Referenced by av_expr_parse_and_eval(), config_props(), DEFINE_BLEND(), do_video_out(), draw_text(), eval_expr(), ff_filter_frame_framed(), filter_frame(), filter_plane(), geq_filter_frame(), get_qscale(), init(), modplug_read_packet(), request_frame(), select_frame(), send_next(), and update_context().

Free a parsed expression previously created with av_expr_parse().

Definition at line 302 of file eval.c.

Referenced by av_expr_free(), av_expr_parse(), av_expr_parse_and_eval(), avfilter_free(), config_input(), config_props(), ff_rate_control_uninit(), ffmpeg_cleanup(), geq_uninit(), parse_expr(), parse_factor(), parse_primary(), parse_subexpr(), parse_term(), process_command(), set_enable_expr(), set_expr(), and uninit().

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 89 of file eval.c.

Referenced by ff_parse_sample_rate(), parse_number_or_die(), parse_points_str(), parse_primary(), var_read_float(), and yae_set_tempo().