normalize route parameters (#37)

src/error.rs

@@ -1,4 +1,4 @@
-use crate::tree::Node;
+use crate::tree::{denormalize_params, Node};
 
 use std::fmt;
 
@@ -49,12 +49,19 @@ impl InsertError {
             route.extend_from_slice(&current.prefix);
         }
 
+        let mut last = current;
+        while let Some(node) = last.children.first() {
+            last = node;
+        }
+
         let mut current = current.children.first();
         while let Some(node) = current {
             route.extend_from_slice(&node.prefix);
             current = node.children.first();
         }
 
+        denormalize_params(&mut route, &last.param_remapping);
+
         InsertError::Conflict {
             with: String::from_utf8(route).unwrap(),
         }

src/params.rs

@@ -139,6 +139,24 @@ impl<'k, 'v> Params<'k, 'v> {
             ParamsKind::Large(vec) => vec.push(param),
         }
     }
+
+    // Transform each key.
+    pub(crate) fn for_each_key_mut(&mut self, f: impl Fn((usize, &mut &'k [u8]))) {
+        match &mut self.kind {
+            ParamsKind::None => {}
+            ParamsKind::Small(arr, len) => arr
+                .iter_mut()
+                .take(*len)
+                .map(|param| &mut param.key)
+                .enumerate()
+                .for_each(f),
+            ParamsKind::Large(vec) => vec
+                .iter_mut()
+                .map(|param| &mut param.key)
+                .enumerate()
+                .for_each(f),
+        }
+    }
 }
 
 /// An iterator over the keys and values of a route's [parameters](crate::Params).