xref: /aosp_15_r20/external/apache-commons-bcel/src/examples/Mini/JJTMiniParserState.java (revision 0c56280ab0842982c46a149f7b9eaa497e31e292)

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
/* Generated By:JJTree: Do not edit this line. JJTMiniParserState.java */

package Mini;

class JJTMiniParserState {
  private java.util.Stack<Node> nodes;
  private java.util.Stack<Integer> marks;

  private int sp;                // number of nodes on stack
  private int mk;                // current mark
  private boolean node_created;

  JJTMiniParserState() {
    nodes = new java.util.Stack<Node>();
    marks = new java.util.Stack<Integer>();
    sp = 0;
    mk = 0;
  }

  /* Determines whether the current node was actually closed and
     pushed.  This should only be called in the final user action of a
     node scope.  */
  boolean nodeCreated() {
    return node_created;
  }

  /* Call this to reinitialize the node stack.  It is called
     automatically by the parser's ReInit() method. */
  void reset() {
    nodes.removeAllElements();
    marks.removeAllElements();
    sp = 0;
    mk = 0;
  }

  /* Returns the root node of the AST.  It only makes sense to call
     this after a successful parse. */
  Node rootNode() {
    return nodes.elementAt(0);
  }

  /* Pushes a node on to the stack. */
  void pushNode(Node n) {
    nodes.push(n);
    ++sp;
  }

  /* Returns the node on the top of the stack, and remove it from the
     stack.  */
  Node popNode() {
    if (--sp < mk) {
      mk = marks.pop().intValue();
    }
    return nodes.pop();
  }

  /* Returns the node currently on the top of the stack. */
  Node peekNode() {
    return nodes.peek();
  }

  /* Returns the number of children on the stack in the current node
     scope. */
  int nodeArity() {
    return sp - mk;
  }


  void clearNodeScope(Node n) {
    while (sp > mk) {
      popNode();
    }
    mk = marks.pop().intValue();
  }


  void openNodeScope(Node n) {
    marks.push(new Integer(mk));
    mk = sp;
    n.jjtOpen();
  }


  /* A definite node is constructed from a specified number of
     children.  That number of nodes are popped from the stack and
     made the children of the definite node.  Then the definite node
     is pushed on to the stack. */
  void closeNodeScope(Node n, int num) {
    mk = marks.pop().intValue();
    while (num-- > 0) {
      Node c = popNode();
      c.jjtSetParent(n);
      n.jjtAddChild(c, num);
    }
    n.jjtClose();
    pushNode(n);
    node_created = true;
  }


  /* A conditional node is constructed if its condition is true.  All
     the nodes that have been pushed since the node was opened are
     made children of the the conditional node, which is then pushed
     on to the stack.  If the condition is false the node is not
     constructed and they are left on the stack. */
  void closeNodeScope(Node n, boolean condition) {
    if (condition) {
      int a = nodeArity();
      mk = marks.pop().intValue();
      while (a-- > 0) {
        Node c = popNode();
        c.jjtSetParent(n);
        n.jjtAddChild(c, a);
      }
      n.jjtClose();
      pushNode(n);
      node_created = true;
    } else {
      mk = marks.pop().intValue();
      node_created = false;
    }
  }
}