diff options
Diffstat (limited to 'src/common/crypto.c')
| -rw-r--r-- | src/common/crypto.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/common/crypto.c b/src/common/crypto.c index 06b6aa4b51..1d75555b2f 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -2067,6 +2067,26 @@ crypto_rand_uint64(uint64_t max) } } +/** Return a pseudorandom double d, chosen uniformly from the range + * 0.0 <= d < 1.0. + */ +double +crypto_rand_double(void) +{ + /* We just use an unsigned int here; we don't really care about getting + * more than 32 bits of resolution */ + unsigned int uint; + crypto_rand((char*)&uint, sizeof(uint)); +#if SIZEOF_INT == 4 +#define UINT_MAX_AS_DOUBLE 4294967296.0 +#elif SIZEOF_INT == 8 +#define UINT_MAX_AS_DOUBLE 1.8446744073709552e+19 +#else +#error SIZEOF_INT is neither 4 nor 8 +#endif + return ((double)uint) / UINT_MAX_AS_DOUBLE; +} + /** Generate and return a new random hostname starting with <b>prefix</b>, * ending with <b>suffix</b>, and containing no less than * <b>min_rand_len</b> and no more than <b>max_rand_len</b> random base32 |