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1   /* Generated By:JJTree: Do not edit this line. JJTParserState.java */
2   
3   package org.osoco.dyninc.parser;
4   
5   class JJTParserState {
6     private java.util.Stack nodes;
7     private java.util.Stack marks;
8   
9     private int sp;		// number of nodes on stack
10    private int mk;		// current mark
11    private boolean node_created;
12  
13    JJTParserState() {
14      nodes = new java.util.Stack();
15      marks = new java.util.Stack();
16      sp = 0;
17      mk = 0;
18    }
19  
20    /* Determines whether the current node was actually closed and
21       pushed.  This should only be called in the final user action of a
22       node scope.  */
23    boolean nodeCreated() {
24      return node_created;
25    }
26  
27    /* Call this to reinitialize the node stack.  It is called
28       automatically by the parser's ReInit() method. */
29    void reset() {
30      nodes.removeAllElements();
31      marks.removeAllElements();
32      sp = 0;
33      mk = 0;
34    }
35  
36    /* Returns the root node of the AST.  It only makes sense to call
37       this after a successful parse. */
38    Node rootNode() {
39      return (Node)nodes.elementAt(0);
40    }
41  
42    /* Pushes a node on to the stack. */
43    void pushNode(Node n) {
44      nodes.push(n);
45      ++sp;
46    }
47  
48    /* Returns the node on the top of the stack, and remove it from the
49       stack.  */
50    Node popNode() {
51      if (--sp < mk) {
52        mk = ((Integer)marks.pop()).intValue();
53      }
54      return (Node)nodes.pop();
55    }
56  
57    /* Returns the node currently on the top of the stack. */
58    Node peekNode() {
59      return (Node)nodes.peek();
60    }
61  
62    /* Returns the number of children on the stack in the current node
63       scope. */
64    int nodeArity() {
65      return sp - mk;
66    }
67  
68  
69    void clearNodeScope(Node n) {
70      while (sp > mk) {
71        popNode();
72      }
73      mk = ((Integer)marks.pop()).intValue();
74    }
75  
76  
77    void openNodeScope(Node n) {
78      marks.push(new Integer(mk));
79      mk = sp;
80      n.jjtOpen();
81    }
82  
83  
84    /* A definite node is constructed from a specified number of
85       children.  That number of nodes are popped from the stack and
86       made the children of the definite node.  Then the definite node
87       is pushed on to the stack. */
88    void closeNodeScope(Node n, int num) {
89      mk = ((Integer)marks.pop()).intValue();
90      while (num-- > 0) {
91        Node c = popNode();
92        c.jjtSetParent(n);
93        n.jjtAddChild(c, num);
94      }
95      n.jjtClose();
96      pushNode(n);
97      node_created = true;
98    }
99  
100 
101   /* A conditional node is constructed if its condition is true.  All
102      the nodes that have been pushed since the node was opened are
103      made children of the the conditional node, which is then pushed
104      on to the stack.  If the condition is false the node is not
105      constructed and they are left on the stack. */
106   void closeNodeScope(Node n, boolean condition) {
107     if (condition) {
108       int a = nodeArity();
109       mk = ((Integer)marks.pop()).intValue();
110       while (a-- > 0) {
111 	Node c = popNode();
112 	c.jjtSetParent(n);
113 	n.jjtAddChild(c, a);
114       }
115       n.jjtClose();
116       pushNode(n);
117       node_created = true;
118     } else {
119       mk = ((Integer)marks.pop()).intValue();
120       node_created = false;
121     }
122   }
123 }