hru(1): made it actually work

src/hru.rs

@@ -20,64 +20,36 @@ use std::{
 	cmp::Ordering,
 	env::args,
 	io::stdin,
-	process::exit,
+	process::ExitCode,
 };
 
 extern crate sysexits;
 
-use sysexits::EX_SOFTWARE;
-
-fn auto_c(input: u64) -> (u64, u32) {
-	let mut number = input;
-	let mut remainder = 0;
-	let mut exp: u32 = 0;
-
-	if number % 10 > 0 { }
-	else {
-		while remainder == 0 {
-			number /= 10;
-			remainder = number % 10;
-			exp += 1;
-		}
-	}
+use sysexits::EX_DATAERR;
 
+fn convert(input: u64) -> (f64, u32) {
 	let list: Vec<u32> = vec![3, 6, 9, 12, 15, 18, 21, 24, 27, 30];
-	let mut exps = list.iter().peekable();
+	let mut out = (0.0, 0_u32);
 
-	while let Some(i) = exps.next() {
-		match exp.cmp(i) {
+	if input < 1000 { return (input as f64, 0); }
+
+	for n in list {
+		let c = 10_u64.pow(n);
+		match c.cmp(&input) {
 			Ordering::Less => {
-				number = input;
-				break;
+				out = (input as f64 / c as f64, n);
 			},
-			Ordering::Equal => break,
-			Ordering::Greater => {
-				if let Some(p) = exps.peek() {
-					match exp.cmp(p) {
-						Ordering::Less => {
-							let exp_e = 10_u64.checked_pow(exp)
-								.unwrap_or_else(|| { exit(EX_SOFTWARE); });
-
-							let index_e = 10_u64.checked_pow(i.to_owned())
-								.unwrap_or_else(|| { exit(EX_SOFTWARE); });
-
-							number *= exp_e / index_e;
-							exp = *i;
-							break;
-						},
-						Ordering::Greater => continue,
-						_ => break,
-					};
-				}
+			Ordering::Equal => {
+				return (input as f64 / c as f64, n);
 			},
+			Ordering::Greater => {},
 		};
 	}
 
-	(number, exp)
+	out
 }
 
-
-fn main() {
+fn main() -> ExitCode {
 	let argv = args().collect::<Vec<String>>();
 	let mut buf = String::new();
 	let _ = stdin().read_line(&mut buf);
@@ -86,11 +58,11 @@ fn main() {
 		Ok(f) => f,
 		Err(err) => {
 			eprintln!("{}: {}", argv[0], err);
-			exit(1);
+			return ExitCode::from(EX_DATAERR as u8);
 		},
 	};
 
-	let (number, prefix) = auto_c(n);
+	let (number, prefix) = convert(n);
 
 	let si_prefix = format!("{}B", match prefix {
 		3 => "K",
@@ -106,5 +78,9 @@ fn main() {
 		_ => "",
 	});
 
-	println!("{} {}", number.to_string(), si_prefix);
+	let out = ((number * 10.0).round() / 10.0).to_string();
+
+	println!("{} {}", out, si_prefix);
+
+	ExitCode::SUCCESS
 }