Alachisoft.NCache.Parser.GrammarReader Maven / Gradle / Ivy

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Internal package of Alachisoft.
There is a newer version: 5.3.3
package Alachisoft.NCache.Parser;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
// C# Translation of GoldParser, by Marcus Klimstra .
// Based on GOLDParser by Devin Cook .

/**
 * This class is used to read information stored in the very simple file structure used by the Compiled Grammar Table file.
 */
public class GrammarReader {

    private static final String c_filetype = "GOLD Parser Tables/v1.0";
    //private Encoding m_encoding;
    private BufferedInputStream m_reader;
    private java.util.LinkedList m_entryQueue;

    /*
     * constructor
     */
    public GrammarReader(String p_filename) throws IOException {
        try {
            //m_encoding = new UnicodeEncoding(false, true);
            m_reader = new BufferedInputStream(new FileInputStream(p_filename));
            m_entryQueue = new java.util.LinkedList();
        } catch (Exception e) {
            throw new Alachisoft.NCache.Parser.ParserException("Error constructing GrammarReader");
        }

        if (!HasValidHeader()) {
            throw new Alachisoft.NCache.Parser.ParserException("Incorrect file header");
        }
    }

    public GrammarReader(InputStream stream) throws IOException {
        try {
            //m_encoding = new UnicodeEncoding(false, true);
            m_reader = new BufferedInputStream(stream);
            m_entryQueue = new java.util.LinkedList();
        } catch (Exception e) {
            throw new Alachisoft.NCache.Parser.ParserException("Error constructing GrammarReader");
        }

        if (!HasValidHeader()) {
            throw new Alachisoft.NCache.Parser.ParserException("Incorrect file header");
        }
    }

    /*
     * public methods
     */
    public final boolean MoveNext() {
        try {
            EntryContent content = EntryContent.forValue(m_reader.read());
            //EntryContent content = (EntryContent)m_reader.read();
            if (content == EntryContent.Multi) {
                m_entryQueue.clear();
                byte[] buffer = new byte[2];
                m_reader.read(buffer);
                int count = buffer[0];
                for (int n = 0; n < count; n++) {
                    ReadEntry();
                }

                return true;
            } else {
                return false;
            }
        } catch (java.io.IOException e) {
            return false;
        }
    }

    public final Object RetrieveNext() {
        if (m_entryQueue.isEmpty()) {
            return null;
        } else {
            return m_entryQueue.poll();
        }
    }

    public final boolean RetrieveDone() {
        return (m_entryQueue.isEmpty());
    }

    /*
     * private methods
     */
    private boolean HasValidHeader() throws IOException {
        String filetype = ReadString();
        return filetype.equals(c_filetype);
    }

    private String ReadString() throws IOException {
        int pos = 0;
//C# TO JAVA CONVERTER WARNING: Unsigned integer types have no direct equivalent in Java:
//ORIGINAL LINE: byte[] buffer = new byte[1024];
        byte[] buffer = new byte[1024];

        while (true) {
            m_reader.read(buffer, pos, 2);
            if (buffer[pos] == 0) {
                break;
            }
            pos = pos + 2;
        }
        //return "UTF-8";
        return new String(buffer, 0, buffer.length, Charset.forName("UTF-8"));
        //return "GOLD Parser Tables/v1.0";
    }

    private void ReadEntry() throws IOException {
        EntryContent content = EntryContent.forValue(m_reader.read());
        switch (content) {
            case Empty:
                m_entryQueue.offer(new Object());
                break;
            case Boolean:
                boolean boolvalue = (m_reader.read() == 1);
                m_entryQueue.offer(boolvalue);
                break;
            case Byte:
//C# TO JAVA CONVERTER WARNING: Unsigned integer types have no direct equivalent in Java:
//ORIGINAL LINE: byte bytevalue = m_reader.ReadByte();
                byte bytevalue = (byte) m_reader.read();
                m_entryQueue.offer(bytevalue);
                break;
            case Integer:
                //short intvalue = (short) m_reader.read();
                byte[] buffer = new byte[2];
                m_reader.read(buffer);
                short intvalue = (short) (((buffer[1] & 0xFF) << 8) | buffer[0] & 0xFF);//buffer[0];
                m_entryQueue.offer(intvalue);
                break;
            case String:
                String strvalue = ReadString();
                m_entryQueue.offer(strvalue);
                break;
            default:
                throw new ParserException("Error reading CGT: unknown entry-content type");
        }
    }
}