Data Structures | Macros | Enumerations | Functions | Variables

eval.c File Reference

simple arithmetic expression evaluator. More...

#include <float.h>
#include "attributes.h"
#include "avassert.h"
#include "avutil.h"
#include "common.h"
#include "eval.h"
#include "ffmath.h"
#include "log.h"
#include "mathematics.h"
#include "mem.h"
#include "sfc64.h"
#include "time.h"
#include "avstring.h"
#include "reverse.h"

Go to the source code of this file.

Data Structures

struct Parser

struct AVExpr

struct AVExprRoot

Macros

#define MAX_DEPTH 100

#define VARS 10

#define IS_IDENTIFIER_CHAR(c)

#define COMPUTE_NEXT_RANDOM()

Enumerations

enum {
  e_value , e_const , e_func0 , e_func1 ,
  e_func2 , e_squish , e_gauss , e_ld ,
  e_isnan , e_isinf , e_mod , e_max ,
  e_min , e_eq , e_gt , e_gte ,
  e_lte , e_lt , e_pow , e_mul ,
  e_div , e_add , e_last , e_st ,
  e_while , e_taylor , e_root , e_floor ,
  e_ceil , e_trunc , e_round , e_sqrt ,
  e_not , e_random , e_hypot , e_gcd ,
  e_if , e_ifnot , e_print , e_bitand ,
  e_bitor , e_between , e_clip , e_atan2 ,
  e_lerp , e_sgn , e_randomi
}

Functions

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

Parse the string in numstr and return its value as a double.

static int strmatch (const char *s, const char *prefix)

static double etime (double v)

static double eval_expr (Parser *p, AVExpr *e)

static int parse_expr (AVExpr **e, Parser *p)

void av_expr_free (AVExpr *e)

Free a parsed expression previously created with av_expr_parse().

static int parse_primary (AVExpr **e, Parser *p)

static AVExpr * make_eval_expr (int type, int value, AVExpr *p0, AVExpr *p1)

static int parse_pow (AVExpr **e, Parser *p, int *sign)

static int parse_dB (AVExpr **e, Parser *p, int *sign)

static int parse_factor (AVExpr **e, Parser *p)

static int parse_term (AVExpr **e, Parser *p)

static int parse_subexpr (AVExpr **e, Parser *p)

static int verify_expr (AVExpr *e)

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.

static int expr_count (AVExpr *e, unsigned *counter, int size, int type)

int av_expr_count_vars (AVExpr *e, unsigned *counter, int size)

Track the presence of variables and their number of occurrences in a parsed expression.

int av_expr_count_func (AVExpr *e, unsigned *counter, int size, int arg)

Track the presence of user provided functions and their number of occurrences in a parsed expression.

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

Evaluate a previously parsed expression.

int av_expr_parse_and_eval (double *d, 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.

Variables

static const AVClass eval_class

struct {

double bin_val

double dec_val

int8_t exp

} si_prefixes [ 'z' - 'E'+1]

struct {

const char * name

double value

} constants []

Detailed Description

simple arithmetic expression evaluator.

see http://joe.hotchkiss.com/programming/eval/eval.html

Definition in file eval.c.

Macro Definition Documentation

◆ MAX_DEPTH

#define MAX_DEPTH 100

Definition at line 44 of file eval.c.

◆ VARS

#define VARS 10

Definition at line 59 of file eval.c.

Referenced by av_expr_parse(), and eval_expr().

◆ IS_IDENTIFIER_CHAR

#define IS_IDENTIFIER_CHAR ( c )

Value:

((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')

c

static double c[64]

Definition vsrc_mptestsrc.c:89

Definition at line 149 of file eval.c.

Referenced by strmatch().

◆ COMPUTE_NEXT_RANDOM

#define COMPUTE_NEXT_RANDOM ( )

Value:

int idx = av_clip(eval_expr(p, e->param[0]), 0, VARS-1); \

FFSFC64 *s = p->prng_state + idx; \

uint64_t r; \

\

if (!s->counter) { \

r = isnan(p->var[idx]) ? 0 : p->var[idx]; \

ff_sfc64_init(s, r, r, r, 12); \

} \

r = ff_sfc64_get(s); \

p->var[idx] = r; \

s

#define s(width, name)

Definition cbs_vp9.c:198

av_clip

#define av_clip

Definition common.h:100

VARS

#define VARS

Definition eval.c:59

r

#define r

Definition input.c:42

isnan

#define isnan(x)

Definition libm.h:342

ff_sfc64_get

static uint64_t ff_sfc64_get(FFSFC64 *s)

Definition sfc64.h:41

FFSFC64

Definition sfc64.h:37

eval_expr

static void eval_expr(AVFilterContext *ctx)

Definition vf_overlay.c:96

Referenced by eval_expr().

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

Enumerator
e_value
e_const
e_func0
e_func1
e_func2
e_squish
e_gauss
e_ld
e_isnan
e_isinf
e_mod
e_max
e_min
e_eq
e_gt
e_gte
e_lte
e_lt
e_pow
e_mul
e_div
e_add
e_last
e_st
e_while
e_taylor
e_root
e_floor
e_ceil
e_trunc
e_round
e_sqrt
e_not
e_random
e_hypot
e_gcd
e_if
e_ifnot
e_print
e_bitand
e_bitor
e_between
e_clip
e_atan2
e_lerp
e_sgn
e_randomi

Definition at line 161 of file eval.c.

Function Documentation

◆ av_strtod()

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 by 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 110 of file eval.c.

Referenced by ff_parse_sample_rate(), parse_number(), parse_points_str(), parse_primary(), parse_string(), parse_weights(), set_param(), var_read_float(), vgs_eval(), and vgs_parse_numeric_argument().

◆ strmatch()

static int strmatch ( const char * s,

const char * prefix )

static

Definition at line 151 of file eval.c.

Referenced by parse_primary().

◆ etime()

static double etime ( double v )

static

Definition at line 191 of file eval.c.

Referenced by parse_primary().

◆ eval_expr()

static double eval_expr ( Parser * p,

AVExpr * e )

static

Definition at line 196 of file eval.c.

Referenced by av_expr_eval(), and eval_expr().

◆ parse_expr()

static int parse_expr ( AVExpr ** e,

Parser * p )

static

Definition at line 664 of file eval.c.

Referenced by av_expr_parse(), and parse_primary().

◆ av_expr_free()

void av_expr_free ( AVExpr * e )

Free a parsed expression previously created with av_expr_parse().

Definition at line 368 of file eval.c.

◆ parse_primary()

static int parse_primary ( AVExpr ** e,

Parser * p )

static

Definition at line 382 of file eval.c.

Referenced by parse_dB(), and parse_pow().

◆ make_eval_expr()

static AVExpr * make_eval_expr ( int type,

int value,

AVExpr * p0,

AVExpr * p1 )

static

Definition at line 551 of file eval.c.

Referenced by parse_expr(), parse_factor(), parse_subexpr(), and parse_term().

◆ parse_pow()

static int parse_pow ( AVExpr ** e,

Parser * p,

int * sign )

static

Definition at line 567 of file eval.c.

Referenced by parse_dB().

◆ parse_dB()

static int parse_dB ( AVExpr ** e,

Parser * p,

int * sign )

static

Definition at line 574 of file eval.c.

Referenced by parse_factor().

◆ parse_factor()

static int parse_factor ( AVExpr ** e,

Parser * p )

static

Definition at line 589 of file eval.c.

Referenced by parse_term().

◆ parse_term()

static int parse_term ( AVExpr ** e,

Parser * p )

static

Definition at line 616 of file eval.c.

Referenced by parse_subexpr().

◆ parse_subexpr()

static int parse_subexpr ( AVExpr ** e,

Parser * p )

static

Definition at line 640 of file eval.c.

Referenced by parse_expr().

◆ verify_expr()

static int verify_expr ( AVExpr * e )

static

Definition at line 694 of file eval.c.

Referenced by av_expr_parse(), and verify_expr().

◆ av_expr_parse()

int av_expr_parse ( AVExpr ** expr,

const char * s,

const char *const * const_names,

const char *const * func1_names,

double(** funcs1 )(void *, double),

const char *const * func2_names,

double(** funcs2 )(void *, double, double),

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 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_offset log level offset, can be used to silence error messages

log_ctx parent logging context

Returns: >= 0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 735 of file eval.c.

Referenced by addroi_init(), av_expr_parse_and_eval(), config_input(), config_input(), config_input(), config_input(), config_input(), config_input(), config_input(), config_input(), config_output(), config_output(), config_output(), config_params(), config_props(), config_props(), ff_rate_control_init(), generate_kernel(), geq_init(), init(), init(), init(), init(), init(), init(), init_axis_color(), init_cqt(), init_volume(), initialize(), libplacebo_init(), modplug_read_header(), noise_init(), nppscale_parse_expr(), process_command(), process_command(), process_command(), process_command(), process_forced_keyframes(), scale_parse_expr(), set_enable_expr(), set_expr(), set_expr(), set_expr(), set_expr(), set_expr(), set_expr(), setts_init(), and vgs_parse_numeric_argument().

◆ expr_count()

static int expr_count ( AVExpr * e,

unsigned * counter,

int size,

int type )

static

Definition at line 798 of file eval.c.

Referenced by av_expr_count_func(), av_expr_count_vars(), and expr_count().

◆ av_expr_count_vars()

int av_expr_count_vars ( AVExpr * e,

unsigned * counter,

int size )

Track the presence of variables and their number of occurrences in a parsed expression.

Parameters: e the AVExpr to track variables in

counter a zero-initialized array where the count of each variable will be stored

size size of array

Returns: 0 on success, a negative value indicates that no expression or array was passed or size was zero

Definition at line 814 of file eval.c.

Referenced by check_exprs(), check_exprs(), nppscale_scale(), and scale_frame().

◆ av_expr_count_func()

int av_expr_count_func ( AVExpr * e,

unsigned * counter,

int size,

int arg )

Track the presence of user provided functions and their number of occurrences in a parsed expression.

Parameters: e the AVExpr to track user provided functions in

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 up to 5 entries.

size size of array

arg number of arguments the counted functions have

Returns: 0 on success, a negative value indicates that no expression or array was passed or size was zero

Definition at line 819 of file eval.c.

Referenced by geq_init().

◆ av_expr_eval()

double av_expr_eval ( AVExpr * e,

const double * const_values,

void * opaque )

Evaluate a previously parsed expression.

Parameters: e the AVExpr to evaluate

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 824 of file eval.c.

Referenced by activate(), activate(), addroi_config_input(), av_expr_parse_and_eval(), config_input(), config_input(), config_output(), config_output(), config_props(), do_eval(), draw_text(), eval_expr(), eval_expr(), eval_expr(), eval_expr(), eval_pts(), evaluate_timeline_at_frame(), filter_channel(), filter_frame(), filter_frame(), filter_frame(), filter_frame(), filter_frame(), filter_frame(), forced_kf_apply(), generate_kernel(), get_max_local_gain(), get_qscale(), get_target_gain(), init(), init_axis_color(), init_cqt(), init_volume(), modplug_read_packet(), noise(), nppscale_eval_dimensions(), output_single_frame(), parse_expr(), request_frame(), scale_eval_dimensions(), select_frame(), set_brightness(), set_contrast(), set_gamma(), set_saturation(), set_volume(), setts_filter(), slice_geq_filter(), update_alpha(), update_context(), update_crops(), and vgs_eval().

◆ av_expr_parse_and_eval()

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(** funcs1 )(void *, double),

const char *const * func2_names,

double(** funcs2 )(void *, double, double),

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_offset log level offset, can be used to silence error messages

log_ctx parent logging context