Add DecimalDisplay for ByteSize decimal prefixes printing helper

Author: ChanTsune

src/lib.rs

@@ -196,6 +196,24 @@ impl ByteSize {
     pub fn binary_display(&self) -> BinaryDisplay {
         BinaryDisplay(self)
     }
+
+    /// Returns an object that implements [`Display`] for SI(decimal) prefixes printing.
+    ///
+    /// [`Display`]: fmt::Display
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bytesize::ByteSize;
+    ///
+    /// assert_eq!("100 B", format!("{}", ByteSize::b(100).decimal_display()));
+    /// assert_eq!("3.0 MB", format!("{}", ByteSize::mb(3).decimal_display()));
+    /// assert_eq!("5.0 TB", format!("{}", ByteSize::tb(5).decimal_display()));
+    /// ```
+    #[inline(always)]
+    pub fn decimal_display(&self) -> DecimalDisplay {
+        DecimalDisplay(self)
+    }
 }
 
 pub fn to_string(bytes: u64, si_prefix: bool) -> String {
@@ -325,6 +343,18 @@ impl<'b> Display for BinaryDisplay<'b> {
     }
 }
 
+/// Helper struct for SI(decimal) prefixes printing with [`format!`] and `{}`.
+///
+/// This `struct` implements the [`Display`] trait.
+/// It is created by the [`decimal_display`](ByteSize::decimal_display) method on [`ByteSize`].
+pub struct DecimalDisplay<'b>(&'b ByteSize);
+
+impl<'b> Display for DecimalDisplay<'b> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        write!(f, "{}", to_string(self.0 .0, false))
+    }
+}
+
 #[cfg(feature = "serde")]
 impl<'de> Deserialize<'de> for ByteSize {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>