Prime generator using Sieve of Eratothenes, uses a BitSet to save space

primesieve.h

void AllPrimesTill(int32_t till, std::vector<int32_t>& primes)
{
    BitSet<true> isPrime(till + 1);
    isPrime.Reset(0);
    isPrime.Reset(1);

    int32_t cap = static_cast<int32_t>( std::sqrt(till) ) + 1;

    primes.clear();
    for (int32_t i = 2; i <= cap; ++i)
    {
        if (isPrime[i])
        {
            for (int32_t i2 = i * i; i2 <= till; i2 += i)
            {
                isPrime.Reset(i2);
            }
        }
    }

    for (std::size_t i = 0; i < isPrime.Size(); ++i)
    {
        if (isPrime[i])
            primes.push_back(i);
    }
}