1 #ifndef __INC_LIB8TION_RANDOM_H
2 #define __INC_LIB8TION_RANDOM_H
5 ///@defgroup Random Fast random number generators
6 /// Fast 8- and 16- bit unsigned random numbers.
7 /// Significantly faster than Arduino random(), but
8 /// also somewhat less random. You can add entropy.
11 // X(n+1) = (2053 * X(n)) + 13849)
12 #define FASTLED_RAND16_2053 ((uint16_t)(2053))
13 #define FASTLED_RAND16_13849 ((uint16_t)(13849))
15 /// random number seed
16 extern uint16_t rand16seed;// = RAND16_SEED;
18 /// Generate an 8-bit random number
19 LIB8STATIC uint8_t random8(void)
21 rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
22 // return the sum of the high and low bytes, for better
23 // mixing and non-sequential correlation
24 return (uint8_t)(((uint8_t)(rand16seed & 0xFF)) +
25 ((uint8_t)(rand16seed >> 8)));
28 /// Generate a 16 bit random number
29 LIB8STATIC uint16_t random16(void)
31 rand16seed = (rand16seed * FASTLED_RAND16_2053) + FASTLED_RAND16_13849;
35 /// Generate an 8-bit random number between 0 and lim
36 /// @param lim the upper bound for the result
37 LIB8STATIC uint8_t random8_max(uint8_t lim)
39 uint8_t r = random8();
44 /// Generate an 8-bit random number in the given range
45 /// @param min the lower bound for the random number
46 /// @param lim the upper bound for the random number
47 LIB8STATIC uint8_t random8_min_max(uint8_t min, uint8_t lim)
49 uint8_t delta = lim - min;
50 uint8_t r = random8_max(delta) + min;
54 /// Generate an 16-bit random number between 0 and lim
55 /// @param lim the upper bound for the result
56 LIB8STATIC uint16_t random16_max(uint16_t lim)
58 uint16_t r = random16();
59 uint32_t p = (uint32_t)lim * (uint32_t)r;
64 /// Generate an 16-bit random number in the given range
65 /// @param min the lower bound for the random number
66 /// @param lim the upper bound for the random number
67 LIB8STATIC uint16_t random16_min_max( uint16_t min, uint16_t lim)
69 uint16_t delta = lim - min;
70 uint16_t r = random16_max(delta) + min;
74 /// Set the 16-bit seed used for the random number generator
75 LIB8STATIC void random16_set_seed(uint16_t seed)
80 /// Get the current seed value for the random number generator
81 LIB8STATIC uint16_t random16_get_seed(void)
86 /// Add entropy into the random number generator
87 LIB8STATIC void random16_add_entropy(uint16_t entropy)
89 rand16seed += entropy;