Do not trim each forward slash when not required.

Author: o0Ignition0o

src/lib.rs

@@ -456,13 +456,15 @@ impl Url {
 
         if self.slice(self.scheme_end + 1..).starts_with("//") {
             // URL with authority
-            match self.byte_at(self.username_end) {
-                b':' => {
-                    assert!(self.host_start >= self.username_end + 2);
-                    assert_eq!(self.byte_at(self.host_start - 1), b'@');
+            if self.username_end < self.serialization.len() as u32 {
+                match self.byte_at(self.username_end) {
+                    b':' => {
+                        assert!(self.host_start >= self.username_end + 2);
+                        assert_eq!(self.byte_at(self.host_start - 1), b'@');
+                    }
+                    b'@' => assert!(self.host_start == self.username_end + 1),
+                    _ => assert_eq!(self.username_end, self.scheme_end + 3),
                 }
-                b'@' => assert!(self.host_start == self.username_end + 1),
-                _ => assert_eq!(self.username_end, self.scheme_end + 3),
             }
             assert!(self.host_start >= self.username_end);
             assert!(self.host_end >= self.host_start);

src/parser.rs

@@ -440,7 +440,11 @@ impl<'a> Parser<'a> {
                         .collect::<String>()
                         != "//"
                 });
-                self.after_double_slash(remaining, scheme_type, scheme_end)
+                if let Some(after_prefix) = input.split_prefix("//") {
+                    return self.after_double_slash(after_prefix, scheme_type, scheme_end);
+                } else {
+                    self.after_double_slash(remaining, scheme_type, scheme_end)
+                }
             }
             SchemeType::NotSpecial => self.parse_non_special(input, scheme_type, scheme_end),
         }
@@ -753,6 +757,9 @@ impl<'a> Parser<'a> {
                     debug_assert!(base_url.byte_at(scheme_end) == b':');
                     self.serialization
                         .push_str(base_url.slice(..scheme_end + 1));
+                    if let Some(after_prefix) = input.split_prefix("//") {
+                        return self.after_double_slash(after_prefix, scheme_type, scheme_end);
+                    }
                     return self.after_double_slash(remaining, scheme_type, scheme_end);
                 }
                 let path_start = base_url.path_start;
@@ -1150,7 +1157,11 @@ impl<'a> Parser<'a> {
                 ".." | "%2e%2e" | "%2e%2E" | "%2E%2e" | "%2E%2E" | "%2e." | "%2E." | ".%2e"
                 | ".%2E" => {
                     debug_assert!(self.serialization.as_bytes()[segment_start - 1] == b'/');
-                    self.serialization.truncate(segment_start - 1); // Truncate "/../"
+                    if ends_with_slash {
+                        self.serialization.truncate(segment_start - 1); // Truncate "/../"
+                    } else {
+                        self.serialization.truncate(segment_start); // Truncate ".."
+                    }
                     self.pop_path(scheme_type, path_start);
                     // and then if neither c is U+002F (/), nor url is special and c is U+005C (\), append the empty string to url’s path.
                     if ends_with_slash && !self.serialization.ends_with("/") {