Add precision to file sizes

format.rs

@@ -6,20 +6,75 @@ static IEC_PREFIXES: &'static [&'static str] = &[
     "", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi"
 ];
 
-fn format_bytes(mut amount: u64, kilo: u64, prefixes: &[&str]) -> (String, String) {
+fn format_bytes(mut amount: f64, kilo: f64, prefixes: &[&str]) -> (String, String) {
     let mut prefix = 0;
-    while amount > kilo {
+    while amount >= kilo {
         amount /= kilo;
         prefix += 1;
     }
-    return (format!("{}", amount), prefixes[prefix].to_string());
+
+    if amount < 10.0 && prefix != 0 {
+        (format!("{:.1}", amount), prefixes[prefix].to_string())
+    }
+    else {
+        (format!("{:.0}", amount), prefixes[prefix].to_string())
+    }
 }
 
 #[allow(non_snake_case_functions)]
 pub fn format_IEC_bytes(amount: u64) -> (String, String) {
-    format_bytes(amount, 1024, IEC_PREFIXES)
+    format_bytes(amount as f64, 1024.0, IEC_PREFIXES)
 }
 
 pub fn format_metric_bytes(amount: u64) -> (String, String) {
-    format_bytes(amount, 1000, METRIC_PREFIXES)
+    format_bytes(amount as f64, 1000.0, METRIC_PREFIXES)
+}
+
+#[test]
+fn test_0() {
+    let kk = format_metric_bytes(0);
+    assert!(kk == ("0".to_string(), "".to_string()));
+}
+
+#[test]
+fn test_999() {
+    let kk = format_metric_bytes(999);
+    assert!(kk == ("999".to_string(), "".to_string()));
+}
+
+#[test]
+fn test_1000() {
+    let kk = format_metric_bytes(1000);
+    assert!(kk == ("1.0".to_string(), "K".to_string()));
+}
+
+#[test]
+fn test_1030() {
+    let kk = format_metric_bytes(1030);
+    assert!(kk == ("1.0".to_string(), "K".to_string()));
+}
+
+#[test]
+fn test_1100() {
+    let kk = format_metric_bytes(1100);
+    assert!(kk == ("1.1".to_string(), "K".to_string()));
+}
+
+#[test]
+fn test_1111() {
+    let kk = format_metric_bytes(1111);
+    assert!(kk == ("1.1".to_string(), "K".to_string()));
 }
+
+#[test]
+fn test_104857() {
+    let kk = format_IEC_bytes(126456);
+    assert!(kk == ("123".to_string(), "Ki".to_string()));
+}
+
+#[test]
+fn test_1048576() {
+    let kk = format_IEC_bytes(1048576);
+    assert!(kk == ("1.0".to_string(), "Mi".to_string()));
+}
+