2 files changed, 19 insertions, 1 deletions
diff --git a/askama_shared/src/filters/mod.rs b/askama_shared/src/filters/mod.rs
index 35166ff..672c5b3 100644
--- a/askama_shared/src/filters/mod.rs
+++ b/askama_shared/src/filters/mod.rs
@@ -12,6 +12,7 @@ pub use self::json::json;
 
 use askama_escape::MarkupDisplay;
 use error::Error::Fmt;
+use humansize::{file_size_opts, FileSize};
 use num_traits::cast::NumCast;
 use num_traits::Signed;
 use std::fmt;
@@ -22,12 +23,13 @@ use super::Result;
 // Askama or should refer to a local `filters` module. It should contain all the
 // filters shipped with Askama, even the optional ones (since optional inclusion
 // in the const vector based on features seems impossible right now).
-pub const BUILT_IN_FILTERS: [&str; 21] = [
+pub const BUILT_IN_FILTERS: [&str; 22] = [
     "abs",
     "capitalize",
     "center",
     "e",
     "escape",
+    "filesizeformat",
     "format",
     "indent",
     "into_f64",
@@ -77,6 +79,12 @@ where
     escape(i)
 }
 
+/// Returns adequate string representation (in KB, ..) of number of bytes
+pub fn filesizeformat(b: usize) -> Result<String> {
+    b.file_size(file_size_opts::DECIMAL)
+        .map_err(|_| Fmt(fmt::Error))
+}
+
 /// Formats arguments according to the specified format
 ///
 /// The first argument to this filter must be a string literal (as in normal
@@ -268,6 +276,15 @@ mod tests {
     use std::f64::INFINITY;
 
     #[test]
+    fn test_filesizeformat() {
+        assert_eq!(filesizeformat(0).unwrap(), "0 B");
+        assert_eq!(filesizeformat(999).unwrap(), "999 B");
+        assert_eq!(filesizeformat(1000).unwrap(), "1 KB");
+        assert_eq!(filesizeformat(1023).unwrap(), "1.02 KB");
+        assert_eq!(filesizeformat(1024).unwrap(), "1.02 KB");
+    }
+
+    #[test]
     fn test_linebreaks() {
         assert_eq!(
             linebreaks(&"Foo\nBar Baz").unwrap(),
diff --git a/askama_shared/src/lib.rs b/askama_shared/src/lib.rs
index 9e2ba6c..a8839fa 100644
--- a/askama_shared/src/lib.rs
+++ b/askama_shared/src/lib.rs
@@ -1,6 +1,7 @@
 #![cfg_attr(feature = "cargo-clippy", allow(unused_parens))]
 
 extern crate askama_escape;
+extern crate humansize;
 extern crate num_traits;
 extern crate serde;
 #[macro_use]