/*
 * Copyright (c) 2017, Jaroslav Bachorik <j.bachorik@btrace.io>.
 * 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.  Copyright owner designates
 * this particular file as subject to the "Classpath" exception as provided
 * by the owner 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.
 */
package org.openjdk.btrace.core;

import java.util.HashMap;
import java.util.Map;

/** Simplified trie-based prefix map */
public class PrefixMap {
  private final Node root = new Node();

  public void add(CharSequence val) {
    Node n = root;
    for (int i = 0; i < val.length(); i++) {
      char ch = val.charAt(i);
      Node child = n.getReferencedNode(ch);
      if (child == null) {
        child = new Node();
        n.addReferencedNode(ch, child);
      }
      n = child;
    }
    n.setValue(val);
  }

  public boolean contains(CharSequence val) {
    Node n = root;
    for (int i = 0; i < val.length(); i++) {
      char ch = val.charAt(i);
      Node child = n.getReferencedNode(ch);
      if (child == null) {
        return false;
      }
      if (child.value != null) {
        return true;
      }
      n = child;
    }
    return false;
  }

  private static final class Node {
    private final Map<Character, Node> refs = new HashMap<>();
    private CharSequence value;

    public Node() {
      value = null;
    }

    public Node getReferencedNode(char ch) {
      return refs.get(ch);
    }

    public void addReferencedNode(char ch, Node n) {
      if (!refs.containsKey(ch)) {
        refs.put(ch, n);
      }
    }

    public void setValue(CharSequence val) {
      value = val;
    }
  }
}
