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Data Structures | Macros | Functions | Variables
eval.c File Reference
#include <float.h>
#include "attributes.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
 

Macros

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

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 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. 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

◆ VARS

#define VARS   10

Definition at line 56 of file eval.c.

◆ IS_IDENTIFIER_CHAR

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

Definition at line 146 of file eval.c.

◆ 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; \

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 107 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 148 of file eval.c.

Referenced by parse_primary().

◆ etime()

static double etime ( double  v )
static

Definition at line 181 of file eval.c.

Referenced by parse_primary().

◆ eval_expr()

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

Definition at line 186 of file eval.c.

Referenced by av_expr_eval().

◆ parse_expr()

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

Definition at line 639 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 358 of file eval.c.

Referenced by addroi_uninit(), av_expr_free(), av_expr_parse(), av_expr_parse_and_eval(), avfilter_free(), command(), config_input(), config_output(), config_params(), config_props(), eval_expr(), ff_rate_control_uninit(), generate_kernel(), geq_uninit(), init(), init_axis_color(), init_cqt(), init_volume(), libplacebo_uninit(), noise_close(), nppscale_parse_expr(), nppscale_uninit(), ost_free(), overlay_cuda_uninit(), parse_channel_expressions(), parse_expr(), parse_factor(), parse_primary(), parse_subexpr(), parse_term(), process_command(), scale_parse_expr(), set_enable_expr(), set_expr(), setts_close(), uninit(), and vgs_statement_free().

◆ parse_primary()

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

Definition at line 369 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 530 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 542 of file eval.c.

Referenced by parse_dB().

◆ parse_dB()

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

Definition at line 549 of file eval.c.

Referenced by parse_factor().

◆ parse_factor()

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

Definition at line 564 of file eval.c.

Referenced by parse_term().

◆ parse_term()

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

Definition at line 591 of file eval.c.

Referenced by parse_subexpr().

◆ parse_subexpr()

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

Definition at line 615 of file eval.c.

Referenced by parse_expr().

◆ verify_expr()

static int verify_expr ( AVExpr *  e )
static

Definition at line 669 of file eval.c.

Referenced by av_expr_parse().

◆ 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
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 710 of file eval.c.

Referenced by addroi_init(), av_expr_parse_and_eval(), config_input(), config_output(), config_params(), config_props(), ff_rate_control_init(), generate_kernel(), geq_init(), init(), init_axis_color(), init_cqt(), init_volume(), initialize(), libplacebo_init(), modplug_read_header(), noise_init(), nppscale_parse_expr(), process_command(), process_forced_keyframes(), scale_parse_expr(), set_enable_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 766 of file eval.c.

Referenced by av_expr_count_func(), and av_expr_count_vars().

◆ 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 782 of file eval.c.

Referenced by 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 787 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 792 of file eval.c.

Referenced by activate(), addroi_config_input(), av_expr_parse_and_eval(), config_input(), config_output(), config_props(), do_eval(), draw_text(), eval_expr(), eval_pts(), evaluate_timeline_at_frame(), filter_channel(), 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(**)(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_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 805 of file eval.c.

Referenced by activate(), av_parse_ratio(), calc_persp_luts(), config_input(), config_output_props(), config_props(), drawbox_vaapi_config_output(), eval_expr(), ff_print_eval_expr(), ff_print_formatted_eval_expr(), ff_scale_eval_dimensions(), filter_frame(), generate_kernel(), get_aspect_ratio(), main(), pad_opencl_config_output(), pad_vaapi_config_output(), and set_string_number().

Variable Documentation

◆ eval_class

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,
}

Definition at line 61 of file eval.c.

Referenced by av_expr_eval(), and av_expr_parse().

◆ bin_val

double bin_val

Definition at line 71 of file eval.c.

◆ dec_val

double dec_val

Definition at line 72 of file eval.c.

◆ exp

int8_t exp

Definition at line 73 of file eval.c.

Referenced by ac3_exponent_min_c(), ac3_extract_exponents_c(), acelp_decode_gain_codef(), adpcm_decode_frame(), apply_channel_coupling(), ath(), av_bessel_i0(), av_div_sf_ieee754(), av_mul_sf_ieee754(), bit_allocate(), bitreduction(), comp_harmonic_coeff(), compute_exp_strategy(), config_filter(), config_input(), config_output(), convert_sp2zp(), create_freq_table(), decode(), decode_aiff_header(), decode_subframe(), dnn_detect_parse_yolo_output(), encode_exp_vlc(), encode_exponents(), encode_exponents_blk_ch(), erf(), estimate_pitch(), eval_expr(), evrc_decode_frame(), exit_handler(), fade_gain(), ff_ac3_bit_alloc_calc_psd(), ff_tx_mdct_fwd(), ff_tx_mdct_inv(), filter_dbl(), filter_frame(), fir_to_phase(), gaussian(), generate_min_phase_kernel(), generate_window_func(), get_aiff_header(), get_coef(), get_volume(), hom(), init(), init_gaussian_filter(), init_pass2(), init_weights_pipeline(), mapres(), modify_qscale(), mult(), nb_decode(), noise_filter(), output_gain(), parse_mantissas(), parse_points(), parse_primary(), put_float(), qdm2_fft_decode_tones(), qdm2_fft_init_coefficient(), quant(), quantize_mantissas_blk_ch(), sbr_hf_g_filt_c(), scalbnl(), set_ap1(), set_band_parameters(), set_default_ctl_value(), set_gauss(), set_parameters(), sigmoid(), spectral_flatness(), speex_std_stereo(), stream_component_open(), swri_dither_init(), sws_getGaussianVec(), trc_arib_std_b67_inv(), try_export_flags(), twinvq_mulawinv(), unsharp_opencl_make_filter_params(), vorbis_floor0_decode(), vorbisfloat2float(), and wv_get_value_float().

◆ si_prefixes

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().

◆ name

const char* name

Definition at line 98 of file eval.c.

Referenced by parse_primary().

◆ value

double value

Definition at line 99 of file eval.c.

Referenced by make_eval_expr().

◆ constants

const { ... } constants[]
Initial value:
= {
{ "E", M_E },
{ "PI", M_PI },
{ "PHI", M_PHI },
{ "QP2LAMBDA", FF_QP2LAMBDA },
}

Referenced by jxl_u32(), and parse_primary().

av_clip
#define av_clip
Definition: common.h:100
r
const char * r
Definition: vf_curves.c:127
M_PHI
#define M_PHI
Definition: mathematics.h:61
s
#define s(width, name)
Definition: cbs_vp9.c:198
M_E
#define M_E
Definition: mathematics.h:37
if
if(ret)
Definition: filter_design.txt:179
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
NULL
#define NULL
Definition: coverity.c:32
isnan
#define isnan(x)
Definition: libm.h:342
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:241
eval_expr
static double eval_expr(Parser *p, AVExpr *e)
Definition: eval.c:186
M_PI
#define M_PI
Definition: mathematics.h:67
ff_sfc64_get
static uint64_t ff_sfc64_get(FFSFC64 *s)
Definition: sfc64.h:41
VARS
#define VARS
Definition: eval.c:56
Windows::Graphics::DirectX::Direct3D11::p
IDirect3DDxgiInterfaceAccess _COM_Outptr_ void ** p
Definition: vsrc_gfxcapture_winrt.hpp:53
FF_QP2LAMBDA
#define FF_QP2LAMBDA
factor to convert from H.263 QP to lambda
Definition: avutil.h:226
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