Impelment CandidateGenerator.

src/candidate.rs

@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2025  Nicolás Ortega Froysa <nicolas@ortegas.org>
+ * Author: Nicolás Ortega Froysa <nicolas@ortegas.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pub struct CandidateGenerator {
+	base:u64,
+	first_use:bool,
+}
+
+impl CandidateGenerator {
+	pub fn new() -> CandidateGenerator {
+		CandidateGenerator {
+			base: 0,
+			first_use: true,
+		}
+	}
+
+	pub fn next(&mut self) -> u64 {
+		/*
+		 * All primes, except 2 and 3, will be equal to (n * 6 ± 1). This avoids
+		 * multiples of three, optimizing our counting.
+		 */
+		let val;
+
+		if self.base != 0 {
+			if self.first_use {
+				val = self.base - 1;
+			} else {
+				val = self.base + 1;
+			}
+		} else {
+			if self.first_use {
+				val = 2;
+			} else {
+				val = 3;
+			}
+		}
+
+		if self.first_use {
+			self.first_use = false;
+		} else {
+			self.first_use = true;
+			self.base += 6;
+		}
+
+		val
+	}
+}

src/main.rs

@@ -25,6 +25,8 @@ use std::process;
 use std::rc::Rc;
 use structopt::StructOpt;
 
+mod candidate;
+use candidate::CandidateGenerator;
 mod worker;
 
 #[derive(StructOpt)]
@@ -76,5 +78,10 @@ fn main() {
 		let res = *primes_list.borrow().get(opts.num as usize).unwrap();
 		println!("{}", res);
 	} else {
+		let mut cand_gen = CandidateGenerator::new();
+
+		while primes_list.borrow().len() < opts.num as usize {
+			let cand = cand_gen.next();
+		}
 	}
 }