Move prime finding to its own module.

src/worker.rs

@@ -0,0 +1,83 @@
+/*
+ * 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/>.
+ */
+
+/**
+ * @brief Work on a segment.
+ *
+ * @param start:usize Beginning of the segment (inclusive).
+ * @param end:usize End of the segment (inclusive).
+ *
+ * @return List of primes found in segment.
+ */
+pub fn work_segment(start:usize, end:usize) -> Vec<u64> {
+	let mut found_primes = Vec::<u64>::new();
+	let mut arr = vec![false; end - start + 1];
+
+	if start < 2 && end > 2 {
+		arr[2] = true;
+	}
+	if start < 3 && end > 3 {
+		arr[3] = true;
+	}
+
+	let sqrt_of_num = f64::sqrt(end as f64) as usize;
+	for x in 1..=sqrt_of_num {
+		let xx4 = 4 * x * x;
+		let xx3 = 3 * x * x;
+		for y in 1..=sqrt_of_num {
+			let yy = y * y;
+
+			let n1 = xx4 + yy;
+			if n1 <= end && (n1 % 12 == 1 || n1 % 12 == 5) {
+				arr[n1] = !arr[n1];
+			}
+
+			let n2 = xx3 + yy;
+			if n2 <= end && n2 % 12 == 7 {
+				arr[n2] = !arr[n2];
+			}
+
+			if x > y {
+				let n3 = xx3 - yy;
+				if n3 <= end && n3 % 12 == 11 {
+					arr[n3] = !arr[n3];
+				}
+			}
+		}
+	}
+
+	for i in 5..=sqrt_of_num {
+		if !arr[i] {
+			continue;
+		}
+
+		let mut j = i * i;
+		while j <= end {
+			arr[j] = false;
+			j += i * i;
+		}
+	}
+
+	for i in 2..=end {
+		if arr[i] {
+			found_primes.push(i as u64);
+		}
+	}
+
+	found_primes
+}