diff options
Diffstat (limited to 'src/third_party/wiredtiger/src/support/rand.c')
| -rw-r--r-- | src/third_party/wiredtiger/src/support/rand.c | 98 |
1 files changed, 46 insertions, 52 deletions
diff --git a/src/third_party/wiredtiger/src/support/rand.c b/src/third_party/wiredtiger/src/support/rand.c index dff19325429..264ee711755 100644 --- a/src/third_party/wiredtiger/src/support/rand.c +++ b/src/third_party/wiredtiger/src/support/rand.c @@ -40,83 +40,77 @@ * of zero, in which case they will be stuck on zero forever. Take a local copy * of the values to avoid that, and read/write in atomic, 8B chunks. */ -#undef M_W -#define M_W(r) r.x.w -#undef M_Z -#define M_Z(r) r.x.z +#undef M_W +#define M_W(r) r.x.w +#undef M_Z +#define M_Z(r) r.x.z /* * __wt_random_init -- - * Initialize return of a 32-bit pseudo-random number. + * Initialize return of a 32-bit pseudo-random number. */ void -__wt_random_init(WT_RAND_STATE volatile * rnd_state) - WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) +__wt_random_init(WT_RAND_STATE volatile *rnd_state) WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) { - WT_RAND_STATE rnd; + WT_RAND_STATE rnd; - M_W(rnd) = 521288629; - M_Z(rnd) = 362436069; - *rnd_state = rnd; + M_W(rnd) = 521288629; + M_Z(rnd) = 362436069; + *rnd_state = rnd; } /* * __wt_random_init_seed -- - * Initialize the state of a 32-bit pseudo-random number. - * Use this, instead of __wt_random_init if we are running with multiple - * threads and we want each thread to initialize its own random state based - * on a different random seed. + * Initialize the state of a 32-bit pseudo-random number. Use this, instead of __wt_random_init + * if we are running with multiple threads and we want each thread to initialize its own random + * state based on a different random seed. */ void -__wt_random_init_seed( - WT_SESSION_IMPL *session, WT_RAND_STATE volatile * rnd_state) - WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) +__wt_random_init_seed(WT_SESSION_IMPL *session, WT_RAND_STATE volatile *rnd_state) + WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) { - struct timespec ts; - WT_RAND_STATE rnd; + struct timespec ts; + WT_RAND_STATE rnd; - __wt_epoch(session, &ts); - M_W(rnd) = (uint32_t)(ts.tv_nsec + 521288629); - M_Z(rnd) = (uint32_t)(ts.tv_nsec + 362436069); + __wt_epoch(session, &ts); + M_W(rnd) = (uint32_t)(ts.tv_nsec + 521288629); + M_Z(rnd) = (uint32_t)(ts.tv_nsec + 362436069); - *rnd_state = rnd; + *rnd_state = rnd; } /* * __wt_random -- - * Return a 32-bit pseudo-random number. + * Return a 32-bit pseudo-random number. */ uint32_t -__wt_random(WT_RAND_STATE volatile * rnd_state) - WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) +__wt_random(WT_RAND_STATE volatile *rnd_state) WT_GCC_FUNC_ATTRIBUTE((visibility("default"))) { - WT_RAND_STATE rnd; - uint32_t w, z; + WT_RAND_STATE rnd; + uint32_t w, z; - /* - * Take a copy of the random state so we can ensure that the - * calculation operates on the state consistently regardless of - * concurrent calls with the same random state. - */ - rnd = *rnd_state; - w = M_W(rnd); - z = M_Z(rnd); + /* + * Take a copy of the random state so we can ensure that the calculation operates on the state + * consistently regardless of concurrent calls with the same random state. + */ + rnd = *rnd_state; + w = M_W(rnd); + z = M_Z(rnd); - /* - * Check if the value goes to 0 (from which we won't recover), and reset - * to the initial state. This has additional benefits if a caller fails - * to initialize the state, or initializes with a seed that results in a - * short period. - */ - if (z == 0 || w == 0) { - __wt_random_init(&rnd); - w = M_W(rnd); - z = M_Z(rnd); - } + /* + * Check if the value goes to 0 (from which we won't recover), and reset to the initial state. + * This has additional benefits if a caller fails to initialize the state, or initializes with a + * seed that results in a short period. + */ + if (z == 0 || w == 0) { + __wt_random_init(&rnd); + w = M_W(rnd); + z = M_Z(rnd); + } - M_Z(rnd) = z = 36969 * (z & 65535) + (z >> 16); - M_W(rnd) = w = 18000 * (w & 65535) + (w >> 16); - *rnd_state = rnd; + M_Z(rnd) = z = 36969 * (z & 65535) + (z >> 16); + M_W(rnd) = w = 18000 * (w & 65535) + (w >> 16); + *rnd_state = rnd; - return ((z << 16) + (w & 65535)); + return ((z << 16) + (w & 65535)); } |