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#ifndef __INC_LIB8TION_RANDOM_H
#define __INC_LIB8TION_RANDOM_H
///@ingroup lib8tion
///@defgroup Random Fast random number generators
/// Fast 8- and 16- bit unsigned random numbers.
/// Significantly faster than Arduino random(), but
/// also somewhat less random. You can add entropy.
///@{
// X(n+1) = (2053 * X(n)) + 13849)
#define FASTLED_RAND16_2053 ((uint16_t)(2053))
#define FASTLED_RAND16_13849 ((uint16_t)(13849))
/// random number seed
extern uint16_t rand16seed;// = RAND16_SEED;
/// Generate an 8-bit random number
LIB8STATIC uint8_t random8(void)
{
rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
// return the sum of the high and low bytes, for better
// mixing and non-sequential correlation
return (uint8_t)(((uint8_t)(rand16seed & 0xFF)) +
((uint8_t)(rand16seed >> 8)));
}
/// Generate a 16 bit random number
LIB8STATIC uint16_t random16(void)
{
rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
return rand16seed;
}
/// Generate an 8-bit random number between 0 and lim
/// @param lim the upper bound for the result
LIB8STATIC uint8_t random8_max(uint8_t lim)
{
uint8_t r = random8();
r = (r*lim) >> 8;
return r;
}
/// Generate an 8-bit random number in the given range
/// @param min the lower bound for the random number
/// @param lim the upper bound for the random number
LIB8STATIC uint8_t random8_min_max(uint8_t min, uint8_t lim)
{
uint8_t delta = lim - min;
uint8_t r = random8_max(delta) + min;
return r;
}
/// Generate an 16-bit random number between 0 and lim
/// @param lim the upper bound for the result
LIB8STATIC uint16_t random16_max(uint16_t lim)
{
uint16_t r = random16();
uint32_t p = (uint32_t)lim * (uint32_t)r;
r = p >> 16;
return r;
}
/// Generate an 16-bit random number in the given range
/// @param min the lower bound for the random number
/// @param lim the upper bound for the random number
LIB8STATIC uint16_t random16_min_max( uint16_t min, uint16_t lim)
{
uint16_t delta = lim - min;
uint16_t r = random16_max(delta) + min;
return r;
}
/// Set the 16-bit seed used for the random number generator
LIB8STATIC void random16_set_seed(uint16_t seed)
{
rand16seed = seed;
}
/// Get the current seed value for the random number generator
LIB8STATIC uint16_t random16_get_seed(void)
{
return rand16seed;
}
/// Add entropy into the random number generator
LIB8STATIC void random16_add_entropy(uint16_t entropy)
{
rand16seed += entropy;
}
///@}
#endif
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