#include <Rcpp.h>

using namespace Rcpp;

// [[Rcpp::export]]

NumericVector hashstr2i(std::vector< std::string > x, int ngrps, int prime1=3, int prime2=11, int prime3=15) {

NumericVector out(x.size());

for(uint32_t i =0; i < x.size(); i++)

{

std::string s = x[i];

uint32_t hash = 0;

for(uint32_t j =0; j < s.size(); j++) {

hash += s[j];

hash += (hash << 10);

hash ^= (hash >> 6);

}

hash += (hash << prime1);

hash ^= (hash >> prime2);

hash += (hash << prime3);

out[i] = (hash % ngrps) + 1;

}

return out;

}

// https://stackoverflow.com/questions/114085/fast-string-hashing-algorithm-with-low-collision-rates-with-32-bit-integer