feat: create Display with f64

Signed-off-by: tison <wander4096@gmail.com>

Author: tisonkun

CHANGELOG.md

@@ -4,6 +4,12 @@ All significant changes to this software be documented in this file.
 
 ## Unreleased
 
+## v0.2.1 (2026-06-27)
+
+### New features
+
+* Added `Display::new` for formatting finite, non-negative `f64` byte counts directly.
+
 ## v0.2.0 (2026-06-27)
 
 ### Breaking changes

bsize/src/display.rs

@@ -20,7 +20,8 @@ use crate::Displayable;
 
 /// Create a [`Display`] instance for displaying a byte size.
 ///
-/// See [`Display`] for examples.
+/// See [`Display`] for examples. Use [`Display::new`] when the byte count is already represented
+/// as an `f64`.
 pub fn display(size: impl Displayable) -> Display {
     Display::new(size.canonicalize())
 }
@@ -36,8 +37,8 @@ impl<T: Displayable> BSize<T> {
 
 /// Display wrapper for formatting byte sizes as human-readable strings.
 ///
-/// You may create this wrapper with [`display`] or [`BSize::display`], then pass custom
-/// [`DisplayOptions`] with [`Display::options`].
+/// You may create this wrapper with [`Display::new`], [`display`], or [`BSize::display`], then
+/// pass custom [`DisplayOptions`] with [`Display::options`].
 ///
 /// # Examples
 ///
@@ -68,6 +69,15 @@ impl<T: Displayable> BSize<T> {
 /// assert_eq!("1.5 KiB", bsize::display(1536u64).to_string());
 /// ```
 ///
+/// Use [`Display::new`] when the byte count is already represented as an `f64`.
+///
+/// ```
+/// use bsize::Display;
+///
+/// assert_eq!("1.5 KiB", Display::new(1536.5).to_string());
+/// assert_eq!("1.54 kB", format!("{:.2}", Display::new(1536.5).decimal()));
+/// ```
+///
 /// Use standard formatter precision to control the number of fractional digits.
 ///
 /// ```
@@ -311,7 +321,24 @@ impl Display {
         self
     }
 
-    fn new(size: f64) -> Self {
+    /// Create a [`Display`] instance from a byte count.
+    ///
+    /// This constructor is useful when the byte count is already represented as an `f64`. For
+    /// supported integer byte counts, use [`display`] or [`BSize::display`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use bsize::Display;
+    ///
+    /// assert_eq!("2.5 KiB", Display::new(2560.0).to_string());
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// Panics if the `size` is not finite or is negative.
+    pub fn new(size: f64) -> Self {
+        assert!(size.is_finite() && size >= 0.0);
         let options = DisplayOptions::BINARY;
         Self { size, options }
     }
@@ -505,6 +532,24 @@ mod tests {
         assert_snapshot!(format!("{:.2}", Display::new(2500.5).decimal()), @"2.50 kB");
     }
 
+    #[test]
+    #[should_panic]
+    fn test_new_rejects_nan_size() {
+        Display::new(f64::NAN);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_new_rejects_infinite_size() {
+        Display::new(f64::INFINITY);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_new_rejects_negative_size() {
+        Display::new(-1.0);
+    }
+
     #[test]
     fn test_formats_default_binary() {
         assert_snapshot!(display(999u64), @"999 B");

bsize/src/lib.rs

@@ -52,45 +52,24 @@
 //!
 //! ```
 //! use bsize::BSize;
+//! use bsize::DisplayOptions;
+//! use bsize::DisplayBaseUnit;
+//! use bsize::DisplayScale;
 //!
 //! assert_eq!(
 //!     "518.0 GiB",
 //!     BSize::<usize>::gib(518).display().binary().to_string()
 //! );
+//!
 //! assert_eq!(
 //!     "556.2 GB",
 //!     BSize::<usize>::gib(518).display().decimal().to_string()
 //! );
-//! ```
-//!
-//! Customize display options.
-//!
-//! ```
-//! use bsize::BSize;
-//! use bsize::DisplayBaseUnit;
-//! use bsize::DisplayScale;
-//!
-//! let display = BSize::<u64>::b(1536).display().options(|opts| {
-//!     opts.base_unit(DisplayBaseUnit::Bit)
-//!         .scale(DisplayScale::Kilo)
-//! });
-//!
-//! assert_eq!("12.0 Kibit", display.to_string());
-//! ```
-//!
-//! Replace display options with a shared preset.
-//!
-//! ```
-//! use bsize::DisplayBaseUnit;
-//! use bsize::DisplayOptions;
-//! use bsize::DisplayScale;
 //!
 //! let network_units = DisplayOptions::DECIMAL
 //!     .base_unit(DisplayBaseUnit::Bit)
 //!     .scale(DisplayScale::Mega);
-//!
-//! let display = bsize::display(125_000u64).options(|_| network_units);
-//!
+//! let display = bsize::display(125_000u64).options(|_opts| network_units);
 //! assert_eq!("1.0 Mbit", display.to_string());
 //! ```
 //!