Allow subtraction to underflow

src/main.rs

@@ -1,4 +1,5 @@
 use std::{
+    io::Read,
     ops::{Add, Sub},
     process::exit,
     usize,
@@ -56,7 +57,7 @@ fn main() {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 struct Machine {
     instruction_pointer: usize,
     data_pointer: usize,
@@ -64,8 +65,7 @@ struct Machine {
     instructions: Vec<Instruction>,
 }
 
-
-#[derive(Debug, Default, Clone, Copy, PartialEq)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash)]
 struct Cell {
     value: u8,
 }
@@ -91,6 +91,7 @@ impl Machine {
 
     fn step(&mut self) -> MachineState {
         let instruction = self.instructions.get(self.instruction_pointer).unwrap();
+
         match instruction {
             Instruction::BINC => self.binc(),
             Instruction::BDEC => self.bdec(),
@@ -178,12 +179,10 @@ impl Machine {
 
     fn inp(&mut self) {
         let mut input = String::new();
-        std::io::stdin().read_line(&mut input).unwrap();
-
-        let value = *input.into_bytes().first().unwrap();
+        std::io::stdin().take(1).read_to_string(&mut input).unwrap();
+        let value = input.as_bytes().first().unwrap().to_owned();
 
         let cell = Cell { value };
-
         self.data[self.data_pointer] = cell;
     }
 
@@ -230,25 +229,36 @@ impl Machine {
         std::io::stdin().read_line(&mut input).unwrap();
 
         let repetitions: usize = input.trim().parse().unwrap();
-
-        let bar = indicatif::ProgressBar::new(repetitions as u64);
-        bar.set_style(
-            ProgressStyle::with_template(
-                "{bar:40} | {human_pos}/{human_len} | {eta_precise} | {elapsed_precise}",
-            )
-            .unwrap(),
-        );
-        for _ in 0..repetitions {
-            bar.inc(1);
-            match self.step() {
-                MachineState::Ok => continue,
-                MachineState::EOI => {
-                    self.instruction_pointer -= 1;
-                    break;
+        if repetitions > 10000000 {
+            let bar = indicatif::ProgressBar::new(repetitions as u64);
+            bar.set_style(
+                ProgressStyle::with_template(
+                    "{bar:40} | {human_pos}/{human_len} | {eta_precise} | {elapsed_precise} | {per_sec}",
+                )
+                .unwrap(),
+            );
+            for _ in 0..repetitions {
+                bar.inc(1);
+                match self.step() {
+                    MachineState::Ok => continue,
+                    MachineState::EOI => {
+                        self.instruction_pointer -= 1;
+                        break;
+                    }
+                }
+            }
+            bar.finish();
+        } else {
+            for _ in 0..repetitions {
+                match self.step() {
+                    MachineState::Ok => continue,
+                    MachineState::EOI => {
+                        self.instruction_pointer -= 1;
+                        break;
+                    }
                 }
             }
         }
-        bar.finish();
     }
 }
 
@@ -266,17 +276,13 @@ impl Sub for Cell {
     type Output = Cell;
 
     fn sub(self, rhs: Self) -> Self::Output {
-        if self.value == 0 {
-            Cell { value: 0 }
-        } else {
-            Cell {
-                value: self.value - rhs.value,
-            }
+        Cell {
+            value: self.value - rhs.value,
         }
     }
 }
 #[allow(clippy::upper_case_acronyms)]
-#[derive(PartialEq, Eq, Debug)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 enum Instruction {
     PINC,        // >
     PDEC,        // <