diff options
Diffstat (limited to 'node/Utils.hpp')
| -rw-r--r-- | node/Utils.hpp | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/node/Utils.hpp b/node/Utils.hpp index 7b1994be..ceb29d7e 100644 --- a/node/Utils.hpp +++ b/node/Utils.hpp @@ -253,6 +253,20 @@ public: } /** + * Count the number of bits set in an integer + * + * @param v 64-bit integer + * @return Number of bits set in this integer (0-64) + */ + static inline uint64_t countBits(uint64_t v) + { + v = v - ((v >> 1) & (uint64_t)~(uint64_t)0/3); + v = (v & (uint64_t)~(uint64_t)0/15*3) + ((v >> 2) & (uint64_t)~(uint64_t)0/15*3); + v = (v + (v >> 4)) & (uint64_t)~(uint64_t)0/255*15; + return (uint64_t)(v * ((uint64_t)~(uint64_t)0/255)) >> 56; + } + + /** * Check if a memory buffer is all-zero * * @param p Memory to scan |