| 1 | /* @title: Bit operations */ |
| 2 | #pragma once |
| 3 | #include <stddef.h> |
| 4 | #include <stdint.h> |
| 5 | |
| 6 | static inline size_t popcount(size_t n) { |
| 7 | size_t count = 0; |
| 8 | while (n > 0) { |
| 9 | if (n & 1) |
| 10 | count++; |
| 11 | |
| 12 | n >>= 1; |
| 13 | } |
| 14 | return count; |
| 15 | } |
| 16 | |
| 17 | static inline size_t next_pow2(size_t x) { |
| 18 | size_t p = 1; |
| 19 | if (x == 0) |
| 20 | return 1; |
| 21 | while (p < x) { |
| 22 | if (p > (SIZE_MAX >> 1)) |
| 23 | return p; |
| 24 | p <<= 1; |
| 25 | } |
| 26 | return p; |
| 27 | } |
| 28 | |
| 29 | static inline size_t prev_pow2(size_t x) { |
| 30 | size_t p = 1; |
| 31 | if (x == 0) |
| 32 | return 1; |
| 33 | while (p <= x) { |
| 34 | if (p > (SIZE_MAX >> 1)) |
| 35 | return p; |
| 36 | p <<= 1; |
| 37 | } |
| 38 | return p >> 1; |
| 39 | } |
| 40 | |