stage2 更多的工具库

stage2/utils/map.spl

@@ -116,24 +116,36 @@ fn find_slot(self: *Map, key: *u8): usize {
     var i = self.hash_fn(key) & mask;
     var empty: SlotState = .Empty;
     var occupied: SlotState = .Occupied;
-    while self.states.data[i] != state_code(empty) {
+    var probes: usize = 0;
+    while probes < self.states.cap && self.states.data[i] != state_code(empty) {
         if self.states.data[i] == state_code(occupied) &&
            self.eq_fn(self.keys.data + i * self.key_size, key) {
             ret i;
         }
         i = (i + 1) & mask;
+        probes = probes + 1;
     }
     ret ~(0 as usize);
 }
 
-// 要求容量非零且键不存在，直接写入第一个空槽（重哈希专用）。
+// 要求容量非零且键不存在。优先复用探测链中的第一个墓碑。
 fn place(self: *Map, key: *u8, val: *u8) {
     var mask = self.states.cap - 1;
     var i = self.hash_fn(key) & mask;
     var empty: SlotState = .Empty;
+    var deleted: SlotState = .Deleted;
     var occupied: SlotState = .Occupied;
-    while self.states.data[i] != state_code(empty) {
+    var first_deleted = ~(0 as usize);
+    var probes: usize = 0;
+    while probes < self.states.cap && self.states.data[i] != state_code(empty) {
+        if self.states.data[i] == state_code(deleted) && first_deleted == ~(0 as usize) {
+            first_deleted = i;
+        }
         i = (i + 1) & mask;
+        probes = probes + 1;
+    }
+    if first_deleted != ~(0 as usize) {
+        i = first_deleted;
     }
     copy((self.keys.data + i * self.key_size) as *any, key as *any, self.key_size);
     copy((self.vals.data + i * self.val_size) as *any, val as *any, self.val_size);