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A framework for constructing recognizers, compilers, and translators from grammatical descriptions containing Java, C#, C++, or Python actions.

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package org.antlr.runtime;

import java.io.IOException;
import java.io.FileInputStream;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.util.List;
import java.util.ArrayList;

public class SerializedGrammar {
    public static final String COOKIE = "$ANTLR";
    public static final int FORMAT_VERSION = 1;
    //public static org.antlr.tool.Grammar gr; // TESTING ONLY; remove later

    public String name;
    public char type; // in {l, p, t, c}
    public List rules;

    class Rule {
        String name;
        Block block;
        public Rule(String name, Block block) {
            this.name = name;
            this.block = block;
        }
        public String toString() {
            return name+":"+block;
        }
    }

    class Block {
        List[] alts;
        public Block(List[] alts) {
            this.alts = alts;
        }
        public String toString() {
            StringBuffer buf = new StringBuffer();
            buf.append("(");
            for (int i = 0; i < alts.length; i++) {
                List alt = alts[i];
                if ( i>0 ) buf.append("|");
                buf.append(alt.toString());
            }
            buf.append(")");
            return buf.toString();
        }
    }

    class TokenRef {
        int ttype;
        public TokenRef(int ttype) { this.ttype = ttype; }
        public String toString() { return String.valueOf(ttype); }
    }

    class RuleRef {
        int ruleIndex;
        public RuleRef(int ruleIndex) { this.ruleIndex = ruleIndex; }
        public String toString() { return String.valueOf(ruleIndex); }
    }

    public SerializedGrammar(String filename) throws IOException {
        System.out.println("loading "+filename);
        FileInputStream fis = new FileInputStream(filename);
        BufferedInputStream bos = new BufferedInputStream(fis);
        DataInputStream in = new DataInputStream(bos);
        readFile(in);
        in.close();
    }

    protected void readFile(DataInputStream in) throws IOException {
        String cookie = readString(in); // get $ANTLR
        if ( !cookie.equals(COOKIE) ) throw new IOException("not a serialized grammar file");
        int version = in.readByte();
        char grammarType = (char)in.readByte();
        this.type = grammarType;
        String grammarName = readString(in);
        this.name = grammarName;
        System.out.println(grammarType+" grammar "+grammarName);
        int numRules = in.readShort();
        System.out.println("num rules = "+numRules);
        rules = readRules(in, numRules);
    }

    protected List readRules(DataInputStream in, int numRules) throws IOException {
        List rules = new ArrayList();
        for (int i=0; i