From 9857b8a456ff07ac423fa45928cf14db225605c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Kijewski?= <rene.kijewski@fu-berlin.de>
Date: Fri, 14 Jun 2024 16:30:16 +0200
Subject: [PATCH] filter: simplify center

---
 askama/src/filters/mod.rs | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/askama/src/filters/mod.rs b/askama/src/filters/mod.rs
index ed380aa8..22d9059d 100644
--- a/askama/src/filters/mod.rs
+++ b/askama/src/filters/mod.rs
@@ -486,31 +486,19 @@ pub fn capitalize(s: impl ToString) -> Result<impl fmt::Display, Infallible> {
 
 /// Centers the value in a field of a given width
 #[inline]
-pub fn center(src: impl ToString, dst_len: usize) -> Result<impl fmt::Display, Infallible> {
-    fn center(src: String, dst_len: usize) -> Result<String, Infallible> {
-        let len = src.len();
-        if dst_len <= len || dst_len >= MAX_LEN {
-            Ok(src)
-        } else {
-            let diff = dst_len - len;
-            let mid = diff / 2;
-            let r = diff % 2;
-            let mut buf = String::with_capacity(dst_len);
-
-            for _ in 0..mid {
-                buf.push(' ');
-            }
-
-            buf.push_str(&src);
+pub fn center(src: impl fmt::Display, width: usize) -> Result<impl fmt::Display, Infallible> {
+    Ok(Center { src, width })
+}
 
-            for _ in 0..mid + r {
-                buf.push(' ');
-            }
+struct Center<T> {
+    src: T,
+    width: usize,
+}
 
-            Ok(buf)
-        }
+impl<T: fmt::Display> fmt::Display for Center<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{: ^1$}", self.src, self.width.min(MAX_LEN))
     }
-    center(src.to_string(), dst_len)
 }
 
 /// Count the words in that string.