Optimize encode code

src/ext/vec.rs

@@ -24,21 +24,3 @@ impl<T: Copy> VecExt<T> for Vec<T> {
         }
     }
 }
-
-pub trait SliceExt<T> {
-    fn rfind(&self, pattern: &[T]) -> Option<usize>;
-}
-
-impl<T: PartialEq> SliceExt<T> for [T] {
-    fn rfind(&self, pattern: &[T]) -> Option<usize> {
-        if pattern.is_empty() || self.len() < pattern.len() {
-            return None;
-        }
-        for i in (0..=self.len() - pattern.len()).rev() {
-            if &self[i..i + pattern.len()] == pattern {
-                return Some(i);
-            }
-        }
-        None
-    }
-}