From 837495980cdb6be74ef30c21bc7816972125566d Mon Sep 17 00:00:00 2001
From: Weihang Lo <me@weihanglo.tw>
Date: Fri, 28 Feb 2025 00:25:56 -0500
Subject: [PATCH 1/3] feat: control precision via standard format options

---
 src/display.rs | 11 ++++++++++-
 src/lib.rs     |  4 ++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/display.rs b/src/display.rs
index e140db71..096e5516 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -128,6 +128,7 @@ impl fmt::Display for Display {
         let unit_prefixes = self.format.unit_prefixes();
         let unit_separator = self.format.unit_separator();
         let unit_suffix = self.format.unit_suffix();
+        let precision = f.precision().unwrap_or(1);
 
         if bytes < unit {
             write!(f, "{bytes}{unit_separator}B")?;
@@ -144,7 +145,7 @@ impl fmt::Display for Display {
 
             write!(
                 f,
-                "{:.1}{unit_separator}{unit_prefix}{unit_suffix}",
+                "{:.precision$}{unit_separator}{unit_prefix}{unit_suffix}",
                 (size / unit.pow(exp as u32) as f64),
             )?;
         }
@@ -293,4 +294,12 @@ mod tests {
         assert_to_string("540.9 PiB", ByteSize::pb(609), Format::Iec);
         assert_to_string("609.0 PB", ByteSize::pb(609), Format::Si);
     }
+
+    #[test]
+    fn precision() {
+        let size = ByteSize::mib(1908);
+        assert_eq!("1.9 GiB".to_string(), format!("{}", size));
+        assert_eq!("2 GiB".to_string(), format!("{:.0}", size));
+        assert_eq!("1.86328 GiB".to_string(), format!("{:.5}", size));
+    }
 }
diff --git a/src/lib.rs b/src/lib.rs
index b766a571..d82d1ce3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -236,9 +236,9 @@ impl fmt::Display for ByteSize {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let display = self.display();
 
-        if f.width().is_none() && f.precision().is_none() {
+        if f.width().is_none() {
             // allocation-free fast path for when no formatting options are specified
-            write!(f, "{display}")
+            display.fmt(f)
         } else {
             f.pad(&display.to_string())
         }

From 5c50e139cbfe2f92cc6a2e7f0c03d27282821462 Mon Sep 17 00:00:00 2001
From: Rob Ede <robjtede@icloud.com>
Date: Fri, 28 Feb 2025 05:54:24 +0000
Subject: [PATCH 2/3] test: fix precision display test

---
 ensure-no-std/Cargo.lock | 2 +-
 src/display.rs           | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/ensure-no-std/Cargo.lock b/ensure-no-std/Cargo.lock
index 76d3ca0d..d43290f2 100644
--- a/ensure-no-std/Cargo.lock
+++ b/ensure-no-std/Cargo.lock
@@ -4,7 +4,7 @@ version = 4
 
 [[package]]
 name = "bytesize"
-version = "1.3.0"
+version = "2.0.0"
 
 [[package]]
 name = "ensure-no-std"
diff --git a/src/display.rs b/src/display.rs
index 096e5516..a17e08d1 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -186,7 +186,7 @@ fn ideal_unit_std(size: f64, unit_base: f64) -> usize {
 
 #[cfg(test)]
 mod tests {
-    use alloc::string::ToString as _;
+    use alloc::{format, string::ToString as _};
 
     use super::*;
 

From 2329d379d71c3c761d6f2e74cd5f921e45c45543 Mon Sep 17 00:00:00 2001
From: Rob Ede <robjtede@icloud.com>
Date: Fri, 28 Feb 2025 05:56:19 +0000
Subject: [PATCH 3/3] docs: update changelog

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5f610638..a58e85af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Add support for precision in `Display` implementations.
+
 ## v2.0.0
 
 - Add support for `no_std` targets.