add formatting trait for irc codes

add an impl off the formatting trait on String to format Strings with
the typical irc formatting codes for bold, italic etc

1 files changed, 50 insertions, 0 deletions

diff --git a/src/util/formatting/truncate.rs b/src/util/formatting/truncate.rs
new file mode 100644
index 0000000..c1b6257
--- /dev/null
+++ b/src/util/formatting/truncate.rs
@@ -0,0 +1,50 @@
+/// Truncates a string after a certain number of characters.
+/// Function always tries to truncate on a word boundary.
+/// Reimplemented from gonzobot.
+pub fn truncate(text: &str, len: usize) -> String {
+    if text.len() <= len {
+        return text.to_string();
+    }
+    format!(
+        "{}…",
+        text[..len]
+            .rsplitn(2, " ")
+            .collect::<Vec<&str>>()
+            .last()
+            .copied()
+            .expect("This can never happen >inb4 it happens")
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::truncate;
+
+    #[test]
+    fn test_truncate_with_input_of_lesser_length_than_limit() {
+        let input = "short text";
+        let result = truncate(input, input.len() + 1);
+        assert_eq!(input, result)
+    }
+
+    #[test]
+    fn test_truncate_with_input_of_equal_length_as_limit() {
+        let input = "short text";
+        let result = truncate(input, input.len());
+        assert_eq!(input, result)
+    }
+
+    #[test]
+    fn test_truncate_with_input_of_greater_length_than_limit() {
+        let input = "some longer text";
+        let result = truncate(input, input.len() - 1);
+        assert_eq!("some longer…", result)
+    }
+
+    #[test]
+    fn test_truncate_with_input_of_greater_length_than_limit_oneword() {
+        let input = "somelongertext";
+        let result = truncate(input, input.len() - 1);
+        assert_eq!("somelongertex…", result)
+    }
+}