diff options
author | Ben Pfaff <blp@nicira.com> | 2012-10-31 17:13:27 -0700 |
---|---|---|
committer | Ben Pfaff <blp@nicira.com> | 2012-11-03 21:13:08 -0700 |
commit | 35bedb6171b62dd528e01dbeb8943bb841365bf5 (patch) | |
tree | 8458a53079e17c20ca7aef2ca571e6cdfc134ffa /lib/util.h | |
parent | fe9d0898828728fc6ce4667527c21beb8fa25ac2 (diff) |
util: New functions for the index of the leftmost or rightmost 1-bit.
These will acquire a user in an upcoming commit.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Diffstat (limited to 'lib/util.h')
-rw-r--r-- | lib/util.h | 21 |
1 files changed, 21 insertions, 0 deletions
@@ -271,6 +271,27 @@ zero_rightmost_1bit(uintmax_t x) { return x & (x - 1); } + +/* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 3), or 32 + * if 'x' is 0. + * + * Unlike the other functions for rightmost 1-bits, this function only works + * with 32-bit integers. */ +static inline uint32_t +rightmost_1bit_idx(uint32_t x) +{ + return x ? ctz(x) : 32; +} + +/* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 6), or 32 + * if 'x' is 0. + * + * This function only works with 32-bit integers. */ +static inline uint32_t +leftmost_1bit_idx(uint32_t x) +{ + return x ? log_2_floor(x) : 32; +} bool is_all_zeros(const uint8_t *, size_t); bool is_all_ones(const uint8_t *, size_t); |