refactor+perf: revamp codebase

src/main.rs

@@ -2,7 +2,7 @@ use std::collections::HashMap;
 use std::fs::File;
 use std::io::{self, BufRead, BufReader};
 
-fn retrieve(memory: &mut HashMap<String, i64>, ops: Vec<String>) -> i64 {
+fn retrieve(memory: &HashMap<String, i64>, ops: &[String]) -> i64 {
     if ops.len() >= 3 {
         *memory.get(&ops[2]).unwrap_or(&0)
     } else {
@@ -10,16 +10,16 @@ fn retrieve(memory: &mut HashMap<String, i64>, ops: Vec<String>) -> i64 {
     }
 }
 
-fn branch(labels: &HashMap<String, usize>, ops: Vec<String>) -> usize {
+fn branch(labels: &HashMap<String, usize>, ops: &[String]) -> usize {
     if ops.len() >= 3 {
-        return *labels.get(&ops[2]).unwrap();
+        *labels.get(&ops[2]).unwrap_or(&0)
     } else {
-        return *labels.get(&ops[1]).unwrap();
+        *labels.get(&ops[1]).unwrap_or(&0)
     }
 }
 
 fn process(
-    line: String,
+    line: &str,
     accumulator: &mut i64,
     memory: &mut HashMap<String, i64>,
     labels: &HashMap<String, usize>,
@@ -27,70 +27,57 @@ fn process(
 ) -> usize {
     let ops: Vec<String> = line.split_whitespace().map(String::from).collect();
 
-    let options: Vec<&str> = if ops.len() >= 3 {
-        vec![ops[0].as_str(), ops[1].as_str()]
-    } else {
-        vec![ops[0].as_str()]
-    };
-
-    for op in options {
-        match op {
-            "INP" => {
-                let mut s = String::new();
-                io::stdin().read_line(&mut s).unwrap();
-                *accumulator = s.trim().parse::<i64>().unwrap();
+    match ops.get(0).map(String::as_str) {
+        Some("INP") => {
+            let mut s = String::new();
+            io::stdin().read_line(&mut s).unwrap();
+            *accumulator = s.trim().parse::<i64>().unwrap();
+        }
+        Some("OUT") => println!("{}", accumulator),
+        Some("STA") => {
+            let key = if ops.len() >= 3 { &ops[2] } else { &ops[1] };
+            memory.insert(key.clone(), *accumulator);
+        }
+        Some("LDA") => {
+            *accumulator = retrieve(memory, &ops);
+        }
+        Some("ADD") => {
+            if let Ok(value) = ops[1].parse::<i64>() {
+                *accumulator += value;
+            } else {
+                *accumulator += retrieve(memory, &ops);
             }
-            "OUT" => println!("{}", accumulator),
-            "STA" => {
-                if ops.len() >= 3 {
-                    memory.insert(ops[2].clone(), *accumulator);
-                } else {
-                    memory.insert(ops[1].clone(), *accumulator);
-                }
+        }
+        Some("SUB") => {
+            if let Ok(value) = ops[1].parse::<i64>() {
+                *accumulator -= value;
+            } else {
+                *accumulator -= retrieve(memory, &ops);
             }
-            "LDA" => {
-                *accumulator = retrieve(memory, ops.clone());
+        }
+        Some("BRA") => return branch(labels, &ops),
+        Some("BRP") => {
+            if *accumulator >= 0 {
+                return branch(labels, &ops);
             }
-            "ADD" => {
-                if let Ok(value) = ops[1].parse::<i64>() {
-                    *accumulator += value;
-                } else {
-                    *accumulator += retrieve(memory, ops.clone());
-                }
+        }
+        Some("BRZ") => {
+            if *accumulator == 0 {
+                return branch(labels, &ops);
             }
-            "SUB" => {
-                if let Ok(value) = ops[1].parse::<i64>() {
-                    *accumulator -= value;
-                } else {
-                    *accumulator -= retrieve(memory, ops.clone());
-                }
-            }
-            "BRA" => {
-                return branch(labels, ops);
-            }
-            "BRP" => {
-                if *accumulator >= 0 {
-                    return branch(labels, ops);
-                }
-            }
-            "BRZ" => {
-                if *accumulator == 0 {
-                    return branch(labels, ops);
-                }
-            }
-            "HLT" => std::process::exit(0),
-            _ => {
-                if ops.len() > 1 && ops[1] == "DAT" {
-                    memory.insert(
-                        ops[0].clone(),
-                        ops.get(2).and_then(|s| s.parse::<i64>().ok()).unwrap_or(0),
-                    );
-                }
+        }
+        Some("HLT") => std::process::exit(0),
+        _ => {
+            if ops.len() > 1 && ops[1] == "DAT" {
+                memory.insert(
+                    ops[0].clone(),
+                    ops.get(2).and_then(|s| s.parse::<i64>().ok()).unwrap_or(0),
+                );
             }
         }
     }
 
-    return pc + 1;
+    pc + 1
 }
 
 fn main() -> io::Result<()> {
@@ -111,8 +98,8 @@ fn main() -> io::Result<()> {
         }
         let ops: Vec<String> = line.split_whitespace().map(String::from).collect();
         if ops.len() > 1 && ops[1] == "DAT" {
-            labels.insert(ops[0].clone(), ops[2].clone().parse::<usize>().unwrap());
-        } else if ops.len() > 1 && !valid.contains(&&*ops[0].clone()) {
+            labels.insert(ops[0].clone(), ops[2].parse::<usize>().unwrap_or(0));
+        } else if ops.len() > 1 && !valid.contains(&&*ops[0]) {
             labels.insert(ops[0].clone(), index);
         }
         code.push(line);
@@ -121,7 +108,7 @@ fn main() -> io::Result<()> {
     let mut pc: usize = 1;
     while pc < code.len() {
         let line = &code[pc];
-        pc = process(line.to_string(), &mut accumulator, &mut memory, &labels, pc);
+        pc = process(line, &mut accumulator, &mut memory, &labels, pc);
     }
 
     Ok(())