Move prime finding to its own module.

src/main.rs

@@ -16,106 +16,49 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-use std::fs::File;
-use std::io::{BufRead, BufReader};
-use std::path::PathBuf;
+//use std::fs::File;
+//use std::io::{BufRead, BufReader};
+//use std::path::PathBuf;
 use std::process;
 use structopt::StructOpt;
 
+mod worker;
+
 #[derive(StructOpt)]
 #[structopt(about = "A prime number generator and tester.")]
 struct Opt {
 	#[structopt(short, long, help = "Print all found primes")]
 	verbose:bool,
-	#[structopt(short, long, name = "FILE", help = "Import prime numbers from FILE")]
-	import:Option<PathBuf>,
+	//#[structopt(short, long, name = "FILE", help = "Import prime numbers from FILE")]
+	//import:Option<PathBuf>,
 	#[structopt(short, long, help = "Test if num is prime instead of generation")]
 	test:bool,
 	#[structopt(help = "Max of the prime to generate or number to test for primality")]
-	num:u64,
-	#[structopt(short, long, name = "n", default_value = "1", help = "Number of threads to spawn")]
-	jobs:u64,
+	num:usize,
+	//#[structopt(short, long, name = "n", default_value = "1", help = "Number of threads to spawn")]
+	//jobs:u64,
 }
 
-const SEGMENT_SIZE:usize = 0x40000000;
-
 fn main() {
 	let opts = Opt::from_args();
 
-	let mut prime_list = Vec::<usize>::new();
-	let mut arr = vec![false; SEGMENT_SIZE];
-
-	if opts.import.is_some() {
+	/*if opts.import.is_some() {
 		let in_file = File::open(opts.import.unwrap()).unwrap();
 		let reader = BufReader::new(in_file);
 		for p in reader.lines().into_iter() {
 			prime_list.push(p.unwrap().parse().unwrap());
 		}
-	}
+	}*/
 
-	let limit = (opts.num * 5) as usize;
-	if opts.num < 2 || limit > SEGMENT_SIZE {
+	if opts.num < 2 {
 		eprintln!("Invalid value for num: {}", opts.num);
 		process::exit(1);
 	}
-	if opts.num > 2 {
-		arr[2] = true;
-	}
-	if opts.num > 3 {
-		arr[3] = true;
-	}
 
-	let sqrt_of_num = f64::sqrt(opts.num 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 prime_list = worker::work_segment(0, opts.num);
 
-			let n1 = xx4 + yy;
-			if n1 % 12 == 1 || n1 % 12 == 5 {
-				arr[n1] = !arr[n1];
-			}
-
-			let n2 = xx3 + yy;
-			if n2 % 12 == 7 {
-				arr[n2] = !arr[n2];
-			}
-
-			if x > y {
-				let n3 = xx3 - yy;
-				if 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 <= (opts.num as usize) {
-			arr[j] = false;
-			j += i * i;
-		}
-	}
-
-	for i in 2..=(opts.num as usize) {
-		if arr[i] {
-			if opts.verbose && !opts.test {
-				println!("{}", i);
-			}
-			prime_list.push(i);
-		}
-	}
-
-	if !opts.verbose && !opts.test {
-		println!("{}", prime_list.last().unwrap());
-	} else if opts.test {
-		if *prime_list.last().unwrap() == (opts.num as usize) {
+	if opts.test {
+		if *prime_list.last().unwrap() == (opts.num as u64) {
 			if opts.verbose {
 				println!("{} is prime", opts.num);
 			}
@@ -126,5 +69,13 @@ fn main() {
 			}
 			process::exit(1);
 		}
+	} else {
+		if !opts.verbose {
+			println!("{}", prime_list.last().unwrap());
+		} else {
+			for p in prime_list {
+				println!("{}", p);
+			}
+		}
 	}
 }

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
+}