uint32_t plainmod_after_expansion()

in pir.cpp [80:100]

• 14 lines of code
• 5 McCabe index (conditional complexity)

uint32_t plainmod_after_expansion(uint32_t logt, uint32_t N, uint32_t d, 
        uint64_t ele_num, uint64_t ele_size) {

    // Goal: find max logtp such that logtp + ceil(log(ceil(d_root(n)))) <= logt
    // where n = ceil(ele_num / floor(N*logtp / ele_size *8))
    for (uint32_t logtp = logt; logtp >= 2; logtp--) {

        uint64_t n = plaintexts_per_db(logtp, N, ele_num, ele_size);

        if (logtp == logt && n == 1) {
            return logtp - 1;
        }

        if ((double)logtp + ceil(log2(ceil(pow(n, 1.0/(double)d)))) <= logt) {
            return logtp;
        }
    }

    assert(0); // this should never happen
    return logt;
}