| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | #ifndef __INC_LIB8TION_RANDOM_H | ||
| 2 | #define __INC_LIB8TION_RANDOM_H | ||
| 3 | |||
| 4 | #include <stdint.h> | ||
| 5 | |||
| 6 | #include "../lib8tion/lib8static.h" | ||
| 7 | |||
| 8 | /// @file random8.h | ||
| 9 | /// Fast, efficient random number generators specifically | ||
| 10 | /// designed for high-performance LED programming. | ||
| 11 | |||
| 12 | /// @ingroup lib8tion | ||
| 13 | /// @{ | ||
| 14 | |||
| 15 | /// @defgroup Random Fast Random Number Generators | ||
| 16 | /// Fast 8-bit and 16-bit unsigned random number generators. | ||
| 17 | /// Significantly faster than Arduino random(), but | ||
| 18 | /// also somewhat less random. You can add entropy. | ||
| 19 | /// | ||
| 20 | /// Pseudo-random number generation follows the form: | ||
| 21 | /// @code | ||
| 22 | /// X(n+1) = (2053 * X(n)) + 13849) | ||
| 23 | /// @endcode | ||
| 24 | /// @{ | ||
| 25 | |||
| 26 | /// Multiplier value for pseudo-random number generation | ||
| 27 | #define FASTLED_RAND16_2053 ((uint16_t)(2053)) | ||
| 28 | /// Increment value for pseudo-random number generation | ||
| 29 | #define FASTLED_RAND16_13849 ((uint16_t)(13849)) | ||
| 30 | |||
| 31 | #if defined(LIB8_ATTINY) | ||
| 32 | /// Multiplies a value by the pseudo-random multiplier | ||
| 33 | #define APPLY_FASTLED_RAND16_2053(x) (x << 11) + (x << 2) + x | ||
| 34 | #else | ||
| 35 | /// Multiplies a value by the pseudo-random multiplier | ||
| 36 | #define APPLY_FASTLED_RAND16_2053(x) (x * FASTLED_RAND16_2053) | ||
| 37 | #endif | ||
| 38 | |||
| 39 | /// Seed for the random number generator functions | ||
| 40 | extern uint16_t rand16seed; // = RAND16_SEED; | ||
| 41 | |||
| 42 | /// Generate an 8-bit random number | ||
| 43 | /// @returns random 8-bit number, in the range 0-255 | ||
| 44 | 174268 | LIB8STATIC uint8_t random8() { | |
| 45 | 174268 | rand16seed = APPLY_FASTLED_RAND16_2053(rand16seed) + FASTLED_RAND16_13849; | |
| 46 | // return the sum of the high and low bytes, for better | ||
| 47 | // mixing and non-sequential correlation | ||
| 48 | 174268 | return (uint8_t)(((uint8_t)(rand16seed & 0xFF)) + | |
| 49 | 174268 | ((uint8_t)(rand16seed >> 8))); | |
| 50 | } | ||
| 51 | |||
| 52 | /// Generate a 16-bit random number | ||
| 53 | /// @returns random 16-bit number, in the range 0-65535 | ||
| 54 | 17693 | LIB8STATIC uint16_t random16() { | |
| 55 | 17693 | rand16seed = APPLY_FASTLED_RAND16_2053(rand16seed) + FASTLED_RAND16_13849; | |
| 56 | 17693 | return rand16seed; | |
| 57 | } | ||
| 58 | |||
| 59 | /// Generate an 8-bit random number between 0 and lim | ||
| 60 | /// @param lim the upper bound for the result, exclusive | ||
| 61 | 22581 | LIB8STATIC uint8_t random8(uint8_t lim) { | |
| 62 | 22581 | uint8_t r = random8(); | |
| 63 | 22581 | r = (r * lim) >> 8; | |
| 64 | 22581 | return r; | |
| 65 | } | ||
| 66 | |||
| 67 | /// Generate an 8-bit random number in the given range | ||
| 68 | /// @param min the lower bound for the random number, inclusive | ||
| 69 | /// @param lim the upper bound for the random number, exclusive | ||
| 70 | 48 | LIB8STATIC uint8_t random8(uint8_t min, uint8_t lim) { | |
| 71 | 48 | uint8_t delta = lim - min; | |
| 72 | 48 | uint8_t r = random8(delta) + min; | |
| 73 | 48 | return r; | |
| 74 | } | ||
| 75 | |||
| 76 | /// Generate an 16-bit random number between 0 and lim | ||
| 77 | /// @param lim the upper bound for the result, exclusive | ||
| 78 | LIB8STATIC uint16_t random16(uint16_t lim) { | ||
| 79 | uint16_t r = random16(); | ||
| 80 | uint32_t p = (uint32_t)lim * (uint32_t)r; | ||
| 81 | r = p >> 16; | ||
| 82 | return r; | ||
| 83 | } | ||
| 84 | |||
| 85 | /// Generate an 16-bit random number in the given range | ||
| 86 | /// @param min the lower bound for the random number, inclusive | ||
| 87 | /// @param lim the upper bound for the random number, exclusive | ||
| 88 | LIB8STATIC uint16_t random16(uint16_t min, uint16_t lim) { | ||
| 89 | uint16_t delta = lim - min; | ||
| 90 | uint16_t r = random16(delta) + min; | ||
| 91 | return r; | ||
| 92 | } | ||
| 93 | |||
| 94 | /// Set the 16-bit seed used for the random number generator | ||
| 95 | 96 | LIB8STATIC void random16_set_seed(uint16_t seed) { rand16seed = seed; } | |
| 96 | |||
| 97 | /// Get the current seed value for the random number generator | ||
| 98 | 54 | LIB8STATIC uint16_t random16_get_seed() { return rand16seed; } | |
| 99 | |||
| 100 | /// Add entropy into the random number generator | ||
| 101 | LIB8STATIC void random16_add_entropy(uint16_t entropy) { | ||
| 102 | rand16seed += entropy; | ||
| 103 | } | ||
| 104 | |||
| 105 | /// @} Random | ||
| 106 | /// @} lib8tion | ||
| 107 | |||
| 108 | #endif | ||
| 109 |