Add command parsing example.

examples/parse_command.rs

@@ -0,0 +1,67 @@
+use smtp_codec::parse::command::command;
+use std::io::Write;
+
+fn main() -> std::io::Result<()> {
+    let mut args = std::env::args();
+
+    if let Some(path) = args.nth(1) {
+        let data = std::fs::read(path).unwrap();
+
+        match command(&data) {
+            Ok((remaining, command)) => {
+                println!("[!] {:#?}", command);
+                let serialized = {
+                    let mut serialized = Vec::new();
+                    command.serialize(&mut serialized).unwrap();
+                    String::from_utf8(serialized).unwrap()
+                };
+                print!("[!] {}", serialized);
+
+                if !remaining.is_empty() {
+                    println!("Remaining data in buffer: {:?}", remaining);
+                }
+            }
+            Err(error) => {
+                println!("Error parsing the command. Is it correct? ({:?})", error);
+            }
+        }
+
+        return Ok(());
+    }
+
+    loop {
+        let line = {
+            print!("Enter SMTP command (or \"exit\"): ");
+            std::io::stdout().flush().unwrap();
+
+            let mut line = String::new();
+            std::io::stdin().read_line(&mut line)?;
+            line.replace("\n", "\r\n")
+        };
+
+        if line.trim() == "exit" {
+            break;
+        }
+
+        match command(line.as_bytes()) {
+            Ok((remaining, command)) => {
+                println!("[!] {:#?}", command);
+                let serialized = {
+                    let mut serialized = Vec::new();
+                    command.serialize(&mut serialized).unwrap();
+                    String::from_utf8(serialized).unwrap()
+                };
+                print!("[!] {}", serialized);
+
+                if !remaining.is_empty() {
+                    println!("Remaining data in buffer: {:?}", remaining);
+                }
+            }
+            Err(error) => {
+                println!("Error parsing the command. Is it correct? ({:?})", error);
+            }
+        }
+    }
+
+    Ok(())
+}