| #pragma once | |
| #ifdef _MSC_VER | |
| #include <intrin.h> | |
| #endif | |
| #include <stdint.h> | |
| inline static uint32_t bit_length(uint32_t n) { | |
| const uint32_t n_minus_1 = n - 1; | |
| if (n_minus_1 == 0) { | |
| return 0; | |
| } else { | |
| #ifdef _MSC_VER | |
| unsigned long bsr; | |
| _BitScanReverse(&bsr, n_minus_1); | |
| return bsr + 1; | |
| #else | |
| return 32 - __builtin_clz(n_minus_1); | |
| #endif | |
| } | |
| } |