Pseudo Random Number Generator (PRNG)

Macros
#define	M_RAND_MAX   M_UINT64_MAX

Typedefs
typedef struct M_rand	M_rand_t

Functions
M_rand_t *	M_rand_create (M_uint64 seed)
void	M_rand_destroy (M_rand_t *state)
M_uint64	M_rand (M_rand_t *state)
M_uint64	M_rand_range (M_rand_t *state, M_uint64 min, M_uint64 max)
M_uint64	M_rand_max (M_rand_t *state, M_uint64 max)
M_bool	M_rand_str (M_rand_t *state, const char *charset, char *out, size_t len)
M_rand_t *	M_rand_duplicate (const M_rand_t *state)
void	M_rand_jump (M_rand_t *state)

Detailed Description

This is NOT a cryptographically secure RNG. This should NEVER be used for cryptographic operations.

Macro Definition Documentation

M_RAND_MAX

#define M_RAND_MAX   M_UINT64_MAX

Typedef Documentation

M_rand_t

typedef struct M_rand M_rand_t

Function Documentation

M_rand_create()

M_rand_t * M_rand_create

(

M_uint64

seed

)

Create a random state for use with random number generation.

Parameters

[in]

seed

The seed state. Using the same seed will allow the sequence to be repeated. If 0 the seed will be a combination of system time, local and heap memory addresses. The data is meant to make choosing a random seed harder but still is not cryptographically secure. This not being a cryptographically secure random number generator we are using random data that is not cryptographically secure for speed.

Returns

Random state.

M_rand_destroy()

void M_rand_destroy

(

M_rand_t *

state

)

Destroy a random state.

Parameters

[in,out]

state

The state.

M_rand()

M_uint64 M_rand

(

M_rand_t *

state

)

Generate a random number.

Generates a random number from 0 to M_RAND_MAX.

Parameters

[in,out]

state

The state. Optional, can be NULL, but will incur the overhead of M_rand_create(0); M_rand_destroy(); per iteration if not provided. It is possible, in a tight loop on a very fast system for example, the same number could be generated multiple times if the state is NULL.

Returns

A random number.

M_rand_range()

M_uint64 M_rand_range	(	M_rand_t *	state,
		M_uint64	min,
		M_uint64	max
	)

Generate a random number within a given range.

Range is [min, max). Meaning from min to max-1.

Parameters

[in,out]	state	The state. Optional, can be NULL, but will incur the overhead of M_rand_create(0); M_rand_destroy(); per iteration if not provided. It is possible, in a tight loop on a very fast system for example, the same number could be generated multiple times if the state is NULL.
[in]	min	The min.
[in]	max	The max.

M_rand_max()

M_uint64 M_rand_max	(	M_rand_t *	state,
		M_uint64	max
	)

Generate a random number with a given maximum.

Range is [0, max). Meaning from 0 to max-1.

Parameters

[in,out]	state	The state. Optional, can be NULL, but will incur the overhead of M_rand_create(0); M_rand_destroy(); per iteration if not provided. It is possible, in a tight loop on a very fast system for example, the same number could be generated multiple times if the state is NULL.
[in]	max	The max.

M_rand_str()

M_bool M_rand_str	(	M_rand_t *	state,
		const char *	charset,
		char *	out,
		size_t	len
	)

Generate a random string based on the provided character set.

Parameters

[in,out]	state	The state. Optional, can be NULL, but will incur the overhead of M_rand_create(0); M_rand_destroy(); per iteration if not provided. It is possible, in a tight loop on a very fast system for example, the same string could be generated multiple times if the state is NULL.
[in]	charset	Character set to use to generate the random string.
[out]	out	Buffer to use to hold the resulting random string. Must be len+1 bytes in length or greater to handle NULL terminator.
[in]	len	Number of characters to generate. Actual number of bytes written will be 1 larger for the NULL terminator.

Returns

M_FALSE on usage error. M_TRUE on success.

M_rand_duplicate()

M_rand_t * M_rand_duplicate

(

const M_rand_t *

state

)

Duplicate the state of a random number generator.

If state is NULL this is equivalent to M_rand_create(0).

Parameters

[in,out]

state

The state.

Returns

Random state.

See also

M_rand_jump

M_rand_jump()

void M_rand_jump

(

M_rand_t *

state

)

Advance the random number generator to generate non-overlapping sequences.

Parameters

[in,out]

state

The state.

See also

M_rand_duplicate