Initial commit.

Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "cmpr"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+clap = { version = "3", features = ["derive"] }

src/main.rs

@@ -0,0 +1,59 @@
+use clap::Parser;
+use std::fs;
+use std::fs::File;
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::process;
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+struct Args {
+    /// file A
+    file_a: String,
+
+    /// file B
+    file_b: String,
+}
+
+fn main() {
+    let args = Args::parse();
+
+    let size_a = fs::metadata(&args.file_a).unwrap().len();
+    let size_b = fs::metadata(&args.file_b).unwrap().len();
+
+    if size_a != size_b {
+        println!("Files have different sizes.");
+        process::exit(1);
+    }
+
+    let handle_a = File::open(&args.file_a).unwrap();
+    let handle_b = File::open(&args.file_b).unwrap();
+
+    let mut reader_a = BufReader::new(handle_a);
+    let mut reader_b = BufReader::new(handle_b);
+
+    let mut buf_a = [0; 1024];
+    let mut buf_b = [0; 1024];
+
+    loop {
+        let len_a = reader_a.read(&mut buf_a).unwrap();
+        let len_b = reader_b.read(&mut buf_b).unwrap();
+
+        if len_a == 0 && len_b == 0 {
+            break;
+        }
+
+        if len_a != len_b {
+            println!("Files are NOT equal.");
+            process::exit(2);
+        }
+
+        if buf_a != buf_b {
+            println!("Files are NOT equal.");
+            process::exit(3);
+        }
+    }
+
+    println!("Files are equal.");
+    process::exit(0);
+}