ID generated on windows is incorrect

[namchuai]

On Windows, (amd64), generated id is 0001KPJCYV0000000000000000

Works normally on unix though.

Code:

auto ulid = ulid::CreateNowRand();
auto thread_id = ulid::Marshal(ulid);

[MilesFan]

in ulid_struct.hh, from line 307 to 316

ulid.data[?] = (uint8_t)(std::rand() * 255ull) / RAND_MAX;

is semantically zero, as a uint8_t (max 255) divided by RAND_MAX (32767) is always zero.

change it to ulid.data[?] = (uint8_t)(std::rand() * 255ull / RAND_MAX) will fix it.

The implementation for non-Windows in ulid_uint128.hh is different.