1 files changed, 35 insertions, 0 deletions
diff --git a/src/query_encoding.rs b/src/query_encoding.rs
new file mode 100644
index 0000000..76aed15
--- /dev/null
+++ b/src/query_encoding.rs
@@ -0,0 +1,35 @@
+// Copyright 2019 The rust-url developers.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::borrow::Cow;
+
+pub type EncodingOverride<'a> = Option<&'a dyn Fn(&str) -> Cow<[u8]>>;
+
+pub(crate) fn encode<'a>(encoding_override: EncodingOverride, input: &'a str) -> Cow<'a, [u8]> {
+    if let Some(o) = encoding_override {
+        return o(input);
+    }
+    input.as_bytes().into()
+}
+
+pub(crate) fn decode_utf8_lossy(input: Cow<[u8]>) -> Cow<str> {
+    match input {
+        Cow::Borrowed(bytes) => String::from_utf8_lossy(bytes),
+        Cow::Owned(bytes) => {
+            let raw_utf8: *const [u8];
+            match String::from_utf8_lossy(&bytes) {
+                Cow::Borrowed(utf8) => raw_utf8 = utf8.as_bytes(),
+                Cow::Owned(s) => return s.into(),
+            }
+            // from_utf8_lossy returned a borrow of `bytes` unchanged.
+            debug_assert!(raw_utf8 == &*bytes as *const [u8]);
+            // Reuse the existing `Vec` allocation.
+            unsafe { String::from_utf8_unchecked(bytes) }.into()
+        }
+    }
+}