LR1ItemSet.java

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * This file is part of SableCC.                             *
 * See the file "LICENSE" for copyright information and the  *
 * terms and conditions for copying, distribution and        *
 * modification of SableCC.                                  *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

package org.sablecc.sablecc;

import java.util.Iterator;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.Vector;

@SuppressWarnings({"rawtypes", "unchecked"})
final class LR1ItemSet implements Cloneable, Comparable {
    private final TreeMap items;
    private int hashCode = 0;

    LR1ItemSet() {
        this.items = new TreeMap();
    }

    private LR1ItemSet(LR1ItemSet set
    ) {
        this.items = (TreeMap) set.items.clone();
        this.hashCode = set.hashCode;
    }

    void set
            (LR1Item item) {
        if (items.put(item, item) == null) {
            hashCode += item.hashCode();
            modified_ = true;
        }
    }

    boolean get
            (LR1Item item) {
        return items.get(item) != null;
    }

    LR1Item[] items_;
    boolean modified_ = true;

    private void computeArray() {
        Vector itemVector = new Vector(0);

        for (Iterator e = items.keySet().iterator(); e.hasNext(); ) {
            itemVector.addElement(e.next());
        }

        items_ = new LR1Item[itemVector.size()];
        itemVector.copyInto(items_);
        modified_ = false;
    }

    LR1Item[] items() {
        if (modified_) {
            computeArray();
        }

        return items_;
    }

    @Override
    public String toString() {
        String nl = System.getProperty("line.separator");

        StringBuffer result = new StringBuffer();
        result.append("{" + nl + "\t");

        Production[] productions = Production.productions();
        Symbol[] terminals = Symbol.terminals();
        boolean comma = false;
        for (int i = 0; i < productions.length; i++) {
            int rightsideLength = productions[i].rightside().length;

            for (int j = 0; j <= rightsideLength; j++) {
                LR0Item lr0Item = new LR0Item(productions[i].index, j);

                for (int k = 0; k < terminals.length; k++) {
                    LR1Item item = new LR1Item(lr0Item, terminals[k].index);
                    if (get
                            (item)) {
                        if (comma) {
                            result.append("," + nl + "\t");
                        } else {
                            comma = true;
                        }

                        result.append(item);
                    }
                }
            }
        }

        result.append(nl + "}");
        return result.toString();
    }

    public String toString(Symbol lookahead) {
        String nl = System.getProperty("line.separator");

        LR1Item[] items = items();
        int length = items.length;

        TreeSet strings = new TreeSet();

        for (int i = 0; i < length; i++) {

            String s = items[i].toString(lookahead);
            //System.out.println("s = " + s + " " + " items[i] : " + items[i] + " lookahead : " + lookahead);
            if (s != null) {
                strings.add(s);
            }
        }

        StringBuffer result = new StringBuffer();
        result.append("{");

        boolean colon = false;
        for (Iterator i = strings.iterator(); i.hasNext(); ) {
            if (colon) {
                result.append(",");
                result.append(nl);
            } else {
                colon = true;
                result.append(nl);
            }

            result.append("\t");
            result.append(i.next());
        }

        result.append(nl);
        result.append("}");

        return result.toString();
    }

    @Override
    public Object clone() {
        return new LR1ItemSet(this);
    }

    @Override
    public boolean equals(Object obj) {
        if ((obj == null) ||
                (obj.getClass() != this.getClass())) {
            return false;
        }

        LR1ItemSet set
                = (LR1ItemSet) obj;

        if (set.items.size() != items.size()) {
            return false;
        }

        for (Iterator e = items.keySet().iterator(); e.hasNext(); ) {
            if (!set.get((LR1Item) e.next())) {
                return false;
            }
        }

        return true;
    }

    @Override
    public int hashCode() {
        return hashCode;
    }

    @Override
    public int compareTo(Object object) {
        LR1ItemSet set
                = (LR1ItemSet) object;

        int result = items.size() - set.items.size();

        if (result == 0) {
            Iterator e = items.keySet().iterator();
            Iterator f = set.items.keySet().iterator();

            while (e.hasNext() && f.hasNext() && (result == 0)) {
                result = ((LR1Item) e.next()).compareTo(f.next());
            }

            if (result == 0) {
                if (e.hasNext()) {
                    return 1;
                }

                if (f.hasNext()) {
                    return -1;
                }
            }
        }

        return result;
    }
}