Fix HeaderMap seq -> hash map transition (#15)

The function that rebuilds the map with a new hasher did not correctly
update the hash table. Also, fix mask values.

src/header/map.rs

@@ -1594,6 +1594,8 @@ impl<T> HeaderMap<T> {
             // Initialze the indices
             self.indices = vec![Pos::none(); cap];
 
+            self.mask = cap.wrapping_sub(1) as Size;
+
             // Rebuild the table
             self.rebuild();
         }
@@ -1604,32 +1606,37 @@ impl<T> HeaderMap<T> {
         debug_assert!(!self.is_scan());
 
         // Loop over all entries and re-insert them into the map
-        for entry in &mut self.entries {
+        'outer:
+        for (index, entry) in self.entries.iter_mut().enumerate() {
             let hash = hash_elem_using(&self.danger, &entry.key);
             let mut probe = desired_pos(self.mask, hash);
             let mut dist = 0;
 
+            // Update the entry's hash code
+            entry.hash = hash;
+
             probe_loop!(probe < self.indices.len() as Size, {
                 if let Some((_, entry_hash)) = self.indices[probe as usize].resolve() {
                     // if existing element probed less than us, swap
                     let their_dist = probe_distance(self.mask, entry_hash, probe);
 
                     if their_dist < dist {
+                        // Robinhood
                         break;
                     }
                 } else {
-                    break;
+                    // Vaccant slot
+                    self.indices[probe as usize] = Pos::new(index as Size, hash);
+                    continue 'outer;
                 }
 
                 dist += 1;
             });
 
-            entry.hash = hash;
-
             do_insert_phase_two(
                 &mut self.indices,
                 probe as Size,
-                Pos::new(probe as Size, hash));
+                Pos::new(index as Size, hash));
         }
     }
 
@@ -3015,7 +3022,7 @@ fn probe_distance(mask: Size, hash: HashValue, current: Size) -> Size {
 fn hash_elem_using<K: ?Sized>(danger: &Danger, k: &K) -> HashValue
     where K: FastHash
 {
-    const MASK: u64 = MAX_SIZE as u64;
+    const MASK: u64 = (MAX_SIZE as u64) - 1;
 
     let hash = match *danger {
         // Safe hash

tests/header_map.rs

@@ -131,3 +131,129 @@ fn eq() {
 
     assert_ne!(a, b);
 }
+
+#[test]
+fn insert_all_std_headers() {
+    let mut m = HeaderMap::new();
+
+    for (i, hdr) in STD.iter().enumerate() {
+        m.insert(hdr.clone(), hdr.as_str().to_string());
+
+        for j in 0..(i+1) {
+            assert_eq!(m[&STD[j]], STD[j].as_str());
+        }
+
+        if i != 0 {
+            for j in (i+1)..STD.len() {
+                assert!(m.get(&STD[j]).is_none(), "contained {}; j={}", STD[j].as_str(), j);
+            }
+        }
+    }
+}
+
+#[test]
+fn insert_79_custom_std_headers() {
+    let mut h = HeaderMap::new();
+    let hdrs = custom_std(79);
+
+    for (i, hdr) in hdrs.iter().enumerate() {
+        h.insert(hdr.clone(), hdr.as_str().to_string());
+
+        for j in 0..(i+1) {
+            assert_eq!(h[&hdrs[j]], hdrs[j].as_str());
+        }
+
+        for j in (i+1)..hdrs.len() {
+            assert!(h.get(&hdrs[j]).is_none());
+        }
+    }
+}
+
+fn custom_std(n: usize) -> Vec<HeaderName> {
+    (0..n).map(|i| {
+        let s = format!("{}-{}", STD[i % STD.len()].as_str(), i);
+        s.parse().unwrap()
+    }).collect()
+}
+
+const STD: [HeaderName; 79] = [
+    ACCEPT,
+    ACCEPT_CHARSET,
+    ACCEPT_ENCODING,
+    ACCEPT_LANGUAGE,
+    ACCEPT_PATCH,
+    ACCEPT_RANGES,
+    ACCESS_CONTROL_ALLOW_CREDENTIALS,
+    ACCESS_CONTROL_ALLOW_HEADERS,
+    ACCESS_CONTROL_ALLOW_METHODS,
+    ACCESS_CONTROL_ALLOW_ORIGIN,
+    ACCESS_CONTROL_EXPOSE_HEADERS,
+    ACCESS_CONTROL_MAX_AGE,
+    ACCESS_CONTROL_REQUEST_HEADERS,
+    ACCESS_CONTROL_REQUEST_METHOD,
+    AGE,
+    ALLOW,
+    ALT_SVC,
+    AUTHORIZATION,
+    CACHE_CONTROL,
+    CONNECTION,
+    CONTENT_DISPOSITION,
+    CONTENT_ENCODING,
+    CONTENT_LANGUAGE,
+    CONTENT_LENGTH,
+    CONTENT_LOCATION,
+    CONTENT_MD5,
+    CONTENT_RANGE,
+    CONTENT_SECURITY_POLICY,
+    CONTENT_SECURITY_POLICY_REPORT_ONLY,
+    CONTENT_TYPE,
+    COOKIE,
+    DNT,
+    DATE,
+    ETAG,
+    EXPECT,
+    EXPIRES,
+    FORWARDED,
+    FROM,
+    HOST,
+    IF_MATCH,
+    IF_MODIFIED_SINCE,
+    IF_NONE_MATCH,
+    IF_RANGE,
+    IF_UNMODIFIED_SINCE,
+    LAST_MODIFIED,
+    KEEP_ALIVE,
+    LINK,
+    LOCATION,
+    MAX_FORWARDS,
+    ORIGIN,
+    PRAGMA,
+    PROXY_AUTHENTICATE,
+    PROXY_AUTHORIZATION,
+    PUBLIC_KEY_PINS,
+    PUBLIC_KEY_PINS_REPORT_ONLY,
+    RANGE,
+    REFERER,
+    REFERRER_POLICY,
+    REFRESH,
+    RETRY_AFTER,
+    SERVER,
+    SET_COOKIE,
+    STRICT_TRANSPORT_SECURITY,
+    TE,
+    TK,
+    TRAILER,
+    TRANSFER_ENCODING,
+    TSV,
+    USER_AGENT,
+    UPGRADE,
+    UPGRADE_INSECURE_REQUESTS,
+    VARY,
+    VIA,
+    WARNING,
+    WWW_AUTHENTICATE,
+    X_CONTENT_TYPE_OPTIONS,
+    X_DNS_PREFETCH_CONTROL,
+    X_FRAME_OPTIONS,
+    X_XSS_PROTECTION,
+];