X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Futil.h;h=a1f4bd740226fd899591003eb77afc27fe196200;hb=1db14c13e5a8b1009d97f603fa24fb7984547695;hp=8c9103c612123ccdbcb112ddf232a7e50bac83e4;hpb=8472a3cecc6c370e227dd477470e4a8cf760ddb5;p=sliver-openvswitch.git diff --git a/lib/util.h b/lib/util.h index 8c9103c61..a1f4bd740 100644 --- a/lib/util.h +++ b/lib/util.h @@ -17,6 +17,7 @@ #ifndef UTIL_H #define UTIL_H 1 +#include #include #include #include @@ -241,9 +242,33 @@ char *xreadlink(const char *filename); char *follow_symlinks(const char *filename); void ignore(bool x OVS_UNUSED); + +/* Returns the number of trailing 0-bits in 'n'. Undefined if 'n' == 0. + * + * This compiles to a single machine instruction ("bsf") with GCC on x86. */ +#if !defined(UINT_MAX) || !defined(UINT32_MAX) +#error "Someone screwed up the #includes." +#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX +static inline int +raw_ctz(uint32_t n) +{ + return __builtin_ctz(n); +} +#else +/* Defined in util.c. */ +int raw_ctz(uint32_t n); +#endif + +/* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */ +static inline int +ctz(uint32_t n) +{ + return n ? raw_ctz(n) : 32; +} + int log_2_floor(uint32_t); int log_2_ceil(uint32_t); -int ctz(uint32_t); +int popcount(uint32_t); bool is_all_zeros(const uint8_t *, size_t); bool is_all_ones(const uint8_t *, size_t);