8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

src/java.base/share/classes/java/util/regex/IntHashSet.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.util.regex;
+
+import java.util.Arrays;
+
+/**
+ * A lightweight hashset implementation for positive 'int'. Not safe for
+ * concurrent access.
+ */
+class IntHashSet {
+    private int[] entries;
+    private int[] hashes;
+    private int pos = 0;
+
+    public IntHashSet() {
+        this.entries = new int[16 << 1];      // initCapacity = 16;
+        this.hashes = new int[(16 / 2) | 1];  // odd -> fewer collisions
+        Arrays.fill(this.entries, -1);
+        Arrays.fill(this.hashes, -1);
+    }
+
+    public boolean contains(int i) {
+        int h = hashes[i % hashes.length];
+        while (h != -1) {
+            if (entries[h] == i)
+                return true;
+            h = entries[h + 1];
+        }
+        return false;
+    }
+
+    public void add(int i) {
+        int h0 = i % hashes.length;
+        int next = hashes[h0];
+        //  if invoker guarantees contains(i) checked before add(i)
+        //  the following check is not needed.
+        int next0 = next;
+        while (next0 != -1) {
+            if (entries[next0 ] == i)
+                return;
+            next0 = entries[next0 + 1];
+        }
+        hashes[h0] = pos;
+        entries[pos++] = i;
+        entries[pos++] = next;
+        if (pos == entries.length)
+            expand();
+    }
+
+    public void clear() {
+        Arrays.fill(this.entries, -1);
+        Arrays.fill(this.hashes, -1);
+        pos = 0;
+    }
+
+    private void expand() {
+        int[] old = entries;
+        int[] es = new int[old.length << 1];
+        int hlen = (old.length / 2) | 1;
+        int[] hs = new int[hlen];
+        Arrays.fill(es, -1);
+        Arrays.fill(hs, -1);
+        for (int n = 0; n < pos;) {  // re-hashing
+            int i = old[n];
+            int hsh = i % hlen;
+            int next = hs[hsh];
+            hs[hsh] = n;
+            es[n++] = i;
+            es[n++] = next;
+        }
+        this.entries = es;
+        this.hashes = hs;
+    }
+}