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Pseudo Random Number Generator (PRNG) More...

Detailed Description

Pseudo Random Number Generator (PRNG)

Various implementations of a PRNG are available:

By default, the auto_init_random module is enabled, which initializes the PRNG on startup. However, there is no lower limit on the entropy provided at that time. Unless the periph_hwrng module is used, entropy may be as little as zero (the constant may even be the same across devices).

Modules

 SHAX random number generator
 SHA based random number generator implementation(CSPRNG).
 

Files

file  random.h
 Common interface to the software PRNG.
 

Macros

#define RANDOM_SEED_DEFAULT   (1)
 Seed selected when all tries to collect seeds from a random source failed.
 
#define PRNG_FLOAT   (0)
 Enables support for floating point random number generation.
 

Functions

void random_init (uint32_t s)
 initializes PRNG with a seed
 
void random_init_by_array (uint32_t init_key[], int key_length)
 initialize by an array with array-length init_key is the array for initializing keys key_length is its length slight change for C++, 2004/2/26
 
uint32_t random_uint32 (void)
 generates a random number on [0,0xffffffff]-interval
 
void random_bytes (void *buf, size_t size)
 writes random bytes in the [0,0xff]-interval to memory
 
uint32_t random_uint32_range (uint32_t a, uint32_t b)
 generates a random number r with a <= r < b.
 
double random_real (void)
 generates a random number on [0,1)-real-interval
 
double random_real_inclusive (void)
 generates a random number on [0,1]-real-interval
 
double random_real_exclusive (void)
 generates a random number on (0,1)-real-interval
 
double random_res53 (void)
 generates a random number on [0,1) with 53-bit resolution
 

Macro Definition Documentation

◆ PRNG_FLOAT

#define PRNG_FLOAT   (0)

Enables support for floating point random number generation.

Definition at line 57 of file random.h.

◆ RANDOM_SEED_DEFAULT

#define RANDOM_SEED_DEFAULT   (1)

Seed selected when all tries to collect seeds from a random source failed.

Definition at line 50 of file random.h.

Function Documentation

◆ random_init()

void random_init ( uint32_t  s)

initializes PRNG with a seed

Users only need to call this if the auto_init_random module is disabled, or provides insufficient quality entropy.

Warning
Currently, the random module uses a global state => multiple calls to random_init will reset the existing state of the PRNG.
Parameters
sseed for the PRNG

◆ random_init_by_array()

void random_init_by_array ( uint32_t  init_key[],
int  key_length 
)

initialize by an array with array-length init_key is the array for initializing keys key_length is its length slight change for C++, 2004/2/26

Parameters
init_keyarray of keys (seeds) to initialize the PRNG
key_lengthnumber of elements in init_key

◆ random_real()

double random_real ( void  )

generates a random number on [0,1)-real-interval

Returns
a random number on [0,1)-real-interval

◆ random_real_exclusive()

double random_real_exclusive ( void  )

generates a random number on (0,1)-real-interval

Returns
a random number on (0,1)-real-interval

◆ random_real_inclusive()

double random_real_inclusive ( void  )

generates a random number on [0,1]-real-interval

Returns
a random number on [0,1]-real-interval

◆ random_res53()

double random_res53 ( void  )

generates a random number on [0,1) with 53-bit resolution

Returns
a random number on [0,1) with 53-bit resolution

◆ random_uint32()

uint32_t random_uint32 ( void  )

generates a random number on [0,0xffffffff]-interval

Returns
a random number on [0,0xffffffff]-interval

◆ random_uint32_range()

uint32_t random_uint32_range ( uint32_t  a,
uint32_t  b 
)

generates a random number r with a <= r < b.

Parameters
[in]aminimum for random number
[in]bupper bound for random number
Precondition
a < b
Returns
a random number on [a,b)-interval