--- a
+++ b/src/internals.h
@@ -0,0 +1,30 @@
+#ifndef OUTBREAKER2_INTERNALS_H
+#define OUTBREAKER2_INTERNALS_H
+
+#include <Rcpp.h>
+
+std::vector<int> cpp_are_possible_ancestors(Rcpp::IntegerVector t_inf, size_t i);
+
+size_t cpp_sample1(Rcpp::IntegerVector x);
+
+size_t cpp_pick_possible_ancestor(Rcpp::IntegerVector t_inf, size_t i);
+
+Rcpp::IntegerVector cpp_find_descendents(Rcpp::IntegerVector alpha, size_t i);
+
+Rcpp::IntegerVector cpp_find_local_cases(Rcpp::IntegerVector alpha, size_t i);
+
+Rcpp::List cpp_swap_cases(Rcpp::List param, size_t i);
+
+size_t cpp_get_n_mutations(Rcpp::List data, size_t i, size_t j);
+
+Rcpp::List cpp_lookup_sequenced_ancestor(Rcpp::List data, Rcpp::List param, size_t i);
+
+void lookup_sequenced_ancestor(Rcpp::IntegerVector alpha, Rcpp::IntegerVector kappa, 
+			       Rcpp::LogicalVector has_dna, size_t i, 
+			       size_t *out_alpha, 
+			       size_t *out_n_generations, 
+			       bool *found_sequenced_ancestor
+			       );
+
+
+#endif