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Data Structures | Macros | Functions | Variables
eval.c File Reference

simple arithmetic expression evaluator. More...

#include <float.h>
#include "attributes.h"
#include "avutil.h"
#include "common.h"
#include "eval.h"
#include "ffmath.h"
#include "internal.h"
#include "log.h"
#include "mathematics.h"
#include "time.h"
#include "avstring.h"
#include "timer.h"
#include "reverse.h"

Go to the source code of this file.

Data Structures

struct  Parser
 
struct  AVExpr
 

Macros

#define VARS   10
 
#define IS_IDENTIFIER_CHAR(c)   ((c) - '0' <= 9U || (c) - 'a' <= 25U || (c) - 'A' <= 25U || (c) == '_')
 

Functions

double av_strtod (const char *numstr, char **tail)
 Parse the string in numstr and return its value as a double. More...
 
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(). More...
 
static int parse_primary (AVExpr **e, Parser *p)
 
static AVExprmake_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. More...
 
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. More...
 
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. More...
 
double av_expr_eval (AVExpr *e, const double *const_values, void *opaque)
 Evaluate a previously parsed expression. More...
 
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. More...
 

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

#define VARS   10

Definition at line 56 of file eval.c.

Referenced by av_expr_parse(), and eval_expr().

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

Definition at line 145 of file eval.c.

Referenced by strmatch().

Function Documentation

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
numstra 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.
tailif non-NULL puts here the pointer to the char next after the last parsed character

Definition at line 106 of file eval.c.

Referenced by ff_parse_sample_rate(), open_output_file(), parse_number_or_die(), parse_points_str(), parse_primary(), parse_string(), parse_weights(), set_param(), and var_read_float().

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

Definition at line 147 of file eval.c.

Referenced by parse_primary().

static double etime ( double  v)
static

Definition at line 179 of file eval.c.

Referenced by parse_primary().

static double eval_expr ( Parser p,
AVExpr e 
)
static

Definition at line 184 of file eval.c.

Referenced by av_expr_eval().

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

Definition at line 615 of file eval.c.

Referenced by av_expr_parse(), eval_expr(), and parse_primary().

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

Definition at line 346 of file eval.c.

Referenced by parse_dB(), and parse_pow().

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

Definition at line 506 of file eval.c.

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

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

Definition at line 518 of file eval.c.

Referenced by parse_dB().

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

Definition at line 525 of file eval.c.

Referenced by parse_factor().

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

Definition at line 540 of file eval.c.

Referenced by parse_term().

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

Definition at line 567 of file eval.c.

Referenced by parse_subexpr().

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

Definition at line 591 of file eval.c.

Referenced by parse_expr().

static int verify_expr ( AVExpr e)
static

Definition at line 645 of file eval.c.

Referenced by av_expr_parse().

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
expra 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.
sexpression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
const_namesNULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
func1_namesNULL terminated array of zero terminated strings of funcs1 identifiers
funcs1NULL terminated array of function pointers for functions which take 1 argument
func2_namesNULL terminated array of zero terminated strings of funcs2 identifiers
funcs2NULL terminated array of function pointers for functions which take 2 arguments
log_ctxparent logging context
Returns
>= 0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 685 of file eval.c.

Referenced by addroi_init(), av_expr_parse_and_eval(), config_input(), config_output(), config_props(), ff_rate_control_init(), generate_kernel(), geq_init(), init(), init_axis_color(), init_cqt(), init_output_stream_encode(), init_volume(), initialize(), modplug_read_header(), parse_fontsize(), process_command(), scale_parse_expr(), set_enable_expr(), and set_expr().

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

Definition at line 740 of file eval.c.

Referenced by av_expr_count_func(), and 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
countera zero-initialized array where the count of each variable will be stored
sizesize of array
Returns
0 on success, a negative value indicates that no expression or array was passed or size was zero

Definition at line 756 of file eval.c.

Referenced by check_exprs(), and scale_frame().

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
countera 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 upto 5 entries.
sizesize of array
argnumber 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 761 of file eval.c.

Referenced by geq_init().

double av_expr_eval ( AVExpr e,
const double *  const_values,
void opaque 
)
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
resa pointer to a double where is put the result value of the expression, or NAN in case of error
sexpression as a zero terminated string, for example "1+2^3+5*5+sin(2/3)"
const_namesNULL terminated array of zero terminated strings of constant identifiers, for example {"PI", "E", 0}
const_valuesa zero terminated array of values for the identifiers from const_names
func1_namesNULL terminated array of zero terminated strings of funcs1 identifiers
funcs1NULL terminated array of function pointers for functions which take 1 argument
func2_namesNULL terminated array of zero terminated strings of funcs2 identifiers
funcs2NULL terminated array of function pointers for functions which take 2 arguments
opaquea pointer which will be passed to all functions from funcs1 and funcs2
log_ctxparent logging context
Returns
>= 0 in case of success, a negative value corresponding to an AVERROR code otherwise

Definition at line 776 of file eval.c.

Referenced by activate(), av_parse_ratio(), calc_persp_luts(), config_input(), config_output_props(), config_props(), ff_scale_eval_dimensions(), filter_frame(), func_eval_expr(), func_eval_expr_int_format(), generate_kernel(), get_aspect_ratio(), main(), pad_opencl_config_output(), qsvscale_config_props(), and set_string_number().

Variable Documentation

const AVClass eval_class
static
Initial value:
= {
.class_name = "Eval",
.item_name = av_default_item_name,
.option = NULL,
.log_level_offset_offset = 0x42,
.parent_log_context_offset = 0x42,
}
#define NULL
Definition: coverity.c:32
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235

Definition at line 60 of file eval.c.

Referenced by av_expr_parse().

double bin_val

Definition at line 70 of file eval.c.

double dec_val

Definition at line 71 of file eval.c.

int8_t exp
const { ... } si_prefixes['z' - 'E' + 1]
Initial value:
= {
['y'-'E']= { 8.271806125530276749e-25, 1e-24, -24 },
['z'-'E']= { 8.4703294725430034e-22, 1e-21, -21 },
['a'-'E']= { 8.6736173798840355e-19, 1e-18, -18 },
['f'-'E']= { 8.8817841970012523e-16, 1e-15, -15 },
['p'-'E']= { 9.0949470177292824e-13, 1e-12, -12 },
['n'-'E']= { 9.3132257461547852e-10, 1e-9, -9 },
['u'-'E']= { 9.5367431640625e-7, 1e-6, -6 },
['m'-'E']= { 9.765625e-4, 1e-3, -3 },
['c'-'E']= { 9.8431332023036951e-3, 1e-2, -2 },
['d'-'E']= { 9.921256574801246e-2, 1e-1, -1 },
['h'-'E']= { 1.0159366732596479e2, 1e2, 2 },
['k'-'E']= { 1.024e3, 1e3, 3 },
['K'-'E']= { 1.024e3, 1e3, 3 },
['M'-'E']= { 1.048576e6, 1e6, 6 },
['G'-'E']= { 1.073741824e9, 1e9, 9 },
['T'-'E']= { 1.099511627776e12, 1e12, 12 },
['P'-'E']= { 1.125899906842624e15, 1e15, 15 },
['E'-'E']= { 1.152921504606847e18, 1e18, 18 },
['Z'-'E']= { 1.1805916207174113e21, 1e21, 21 },
['Y'-'E']= { 1.2089258196146292e24, 1e24, 24 },
}

Referenced by av_strtod().

const char* name

Definition at line 97 of file eval.c.

double value

Definition at line 98 of file eval.c.

Referenced by make_eval_expr().

const { ... } constants[]
Initial value:
= {
{ "E", M_E },
{ "PI", M_PI },
{ "PHI", M_PHI },
{ "QP2LAMBDA", FF_QP2LAMBDA },
}
#define M_E
Definition: mathematics.h:37
#define M_PHI
Definition: mathematics.h:49
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:227
#define M_PI
Definition: mathematics.h:52

Referenced by parse_primary().