move primecheck to utils struct

src/is_prime.rs

@@ -1,10 +1,21 @@
-pub mod is_prime {
-    use num_bigint::BigUint;
-    fn log_2(x: BigUint) -> u64 {
+use num_bigint::BigUint;
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+pub struct PrimeUtils {
+    //prime_cache: Vec<BigUint>
+}
+
+impl PrimeUtils {
+
+    pub fn new() -> Self {
+        Self {  }
+    }
+
+    pub fn log_2(self: &Self, x: BigUint) -> u64 {
         x.bits() - 1
     }
     
-    pub fn is_prime(number: &BigUint) -> bool {
+    pub fn is_prime(self: &Self, number: &BigUint) -> bool {
         if BigUint::from(1u8) == *number {
             return false;
         }
@@ -20,7 +31,7 @@ pub mod is_prime {
     
         // number = 2^a - 1
         // a = log2(number + 1)
-        let a = log_2(number+1u8);
+        let a = self.log_2(number+1u8);
         if BigUint::from(2u8).pow(a as u32)-BigUint::from(1u8) != *number {
             let mut i = BigUint::from(1u8);
             let one = BigUint::from(1u8);
@@ -52,6 +63,6 @@ pub mod is_prime {
         } else {
             false
         }
-    } 
+    }
 }
 

src/main.rs

@@ -2,7 +2,7 @@ pub mod is_prime;
 
 use std::{time::SystemTime,thread};
 use num_bigint::BigUint;
-use crate::is_prime::is_prime::is_prime;
+use crate::is_prime::PrimeUtils;
 
 fn p(n: f64) -> f64 {
     let ln_n = n.ln();
@@ -38,7 +38,9 @@ fn main() {
 
     let sys_time = SystemTime::now();
 
-    let n:f64 = 1_000_000f64;
+    let utils = PrimeUtils::new();
+
+    let n:f64 = 1_000f64;
     let nthprime_approx = p(n*1.01) as u128;
     const THREADS: u128 = 12;
     let workloads = nthprime_approx/THREADS;
@@ -56,7 +58,7 @@ fn main() {
             
             loop {
                 number = number + &inc;
-                if is_prime(&number) {
+                if utils.is_prime(&number) {
                     lprimes.push(number.clone());
                 }
                 if number == max {
@@ -85,8 +87,8 @@ fn main() {
             break;
         }
     }
-    let removed = (primes.len()-n as usize).clamp(0, n as usize);
-    if primes.len() > n as usize {
+    let removed = (primes.len()-n as usize).clamp(0, primes.len());
+    if removed != 0 {
         for _ in 0..removed {
             primes.pop();
         }
@@ -98,7 +100,7 @@ fn main() {
         let inc = BigUint::from(1u8);
         loop {
             number = number + &inc;
-            if is_prime(&number) {
+            if utils.is_prime(&number) {
                 primes.push(number.clone());
             }
             if primes.len() == n as usize {