vl_rand.h File Reference

#include <string.h>
#include "vl_memory.h"
#include "vl_numtypes.h"

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Macros
#define	VL_H_RANDOM_SPLIT(randPtr, resultPtr)   (vlRandSplitBytes((randPtr), (resultPtr)))
#define	vlRandFx4(randPtr, resultPtr)
	Generates four random floats.

Functions
VL_API vl_rand	vlRandInit (void)
	Initializes a random state (aka, seed) based on the current time.
VL_API vl_rand	vlRandNext (vl_rand *rand)
	Returns the "next" 64-bit integer.
VL_API void	vlRandFill (vl_rand *rand, void *mem, vl_ularge_t len)
	Fills the specified region of memory with random bytes.
VL_API vl_float32_t	vlRandF (vl_rand *randPtr)
	Generate a random float.
VL_API void	vlRandFx2 (vl_rand *randPtr, vl_float32_t *resultPtr)
	Generates two random floats.
VL_API vl_float64_t	vlRandD (vl_rand *randPtr)
	Generate a random double.

Macro Definition Documentation

VL_H_RANDOM_SPLIT

#define VL_H_RANDOM_SPLIT	(		randPtr,
			resultPtr
	)		(vlRandSplitBytes((randPtr), (resultPtr)))

vlRandFx4

#define vlRandFx4	(		randPtr,
			resultPtr
	)

Value:

    vlRandFx2(randPtr, (vl_float32_t*)(resultPtr));                                                                    \
    vlRandFx2(randPtr, ((vl_float32_t*)(resultPtr)) + 2)

Generates four 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.

Returns

void

Function Documentation

vlRandD()

VL_API vl_float64_t vlRandD

(

vl_rand *

randPtr

)

Generate a random double.

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

Parameters

randPtr

pointer to random state

Complexity of O(1) constant.

Returns

random double.

vlRandF()

VL_API 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()

VL_API void vlRandFill	(	vl_rand *	rand,
		void *	mem,
		vl_ularge_t	len
	)

Fills the specified region of memory with random bytes.

This function operates on blocks of 8 bytes at a time, until it fills in the last few remaining bytes.

Parameters

rand	rand state
mem	destination
len	total number of bytes to fill.

Complexity of O(n) linear.

vlRandFx2()

VL_API 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_API vl_rand vlRandInit

(

void

)

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_API 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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