vl_rand.c File Reference

#include "vl_rand.h"
#include <time.h>
#include <limits.h>

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Macros
#define	VL_IEEE754_FLOAT32_LOW23   0x007FFFFFu
#define	VL_IEEE754_FLOAT32_ONE   0x3F800000u
#define	VL_IEEE754_FLOAT32_LOW23_DW   0x007FFFFF007FFFFFull
#define	VL_IEEE754_FLOAT32_ONE_DW   0x3F8000003F800000ull
#define	VL_IEEE754_FLOAT64_LOW52   0x000FFFFFFFFFFFFFull
#define	VL_IEEE754_FLOAT64_ONE   0x3FF0000000000000ull

Functions
vl_rand	vlRandInit ()
	Initializes a random state (aka, seed) based on the current time.
vl_rand	vlRandNext (vl_rand *rand)
	Returns the "next" 64-bit integer.
void	vlRandFill (vl_rand *rand, void *mem, vl_memsize_t len)
vl_float32_t	vlRandF (vl_rand *rand)
	Generate a random float.
void	vlRandFx2 (vl_rand *rand, vl_float32_t *result)
	Generates two random floats.

Macro Definition Documentation

VL_IEEE754_FLOAT32_LOW23

#define VL_IEEE754_FLOAT32_LOW23   0x007FFFFFu

VL_IEEE754_FLOAT32_LOW23_DW

#define VL_IEEE754_FLOAT32_LOW23_DW   0x007FFFFF007FFFFFull

VL_IEEE754_FLOAT32_ONE

#define VL_IEEE754_FLOAT32_ONE   0x3F800000u

VL_IEEE754_FLOAT32_ONE_DW

#define VL_IEEE754_FLOAT32_ONE_DW   0x3F8000003F800000ull

VL_IEEE754_FLOAT64_LOW52

#define VL_IEEE754_FLOAT64_LOW52   0x000FFFFFFFFFFFFFull

VL_IEEE754_FLOAT64_ONE

#define VL_IEEE754_FLOAT64_ONE   0x3FF0000000000000ull

Function Documentation

vlRandF()

vl_float32_t vlRandF

(

vl_rand *

randPtr

)

Generate a random float.

Range of returned value is in 0...1.

Parameters

randPtr

pointer to random state

Complexity of O(1) constant.

Returns

random float

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vlRandFill()

void vlRandFill	(	vl_rand *	rand,
		void *	mem,
		vl_memsize_t	len )

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vlRandFx2()

void vlRandFx2	(	vl_rand *	randPtr,
		vl_float32_t *	resultPtr )

Generates two random floats.

Range of returned floats is in range of 0...1.

Parameters

randPtr	pointer to random state
resultPtr	where the result will be stored

Complexity of O(1) constant.

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vlRandInit()

vl_rand vlRandInit

(

)

Initializes a random state (aka, seed) based on the current time.

This function can be skipped entirely, assuming another seed integer can be provided.

Complexity of O(1) constant.

Returns

random state/seed.

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vlRandNext()

vl_rand vlRandNext

(

vl_rand *

rand

)

Returns the "next" 64-bit integer.

This function has a side effect of updating the random state.

Complexity of O(1) constant.

Parameters

rand	pointer to random state

Returns

unsigned 64-bit integer

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