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HSQLDB - Lightweight 100% Java SQL Database Engine
There is a newer version: 2.7.2
/* Copyright (c) 2001-2019, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */


package org.hsqldb.persist;

import org.hsqldb.Database;
import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;

/**
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.3
 * @since 1.9.0
 */
public class LobStoreRAFile implements LobStore {

    final int             lobBlockSize;
    String                fileName;
    RandomAccessInterface file;
    Database              database;

    public LobStoreRAFile(Database database, int lobBlockSize) {

        this.database     = database;
        this.lobBlockSize = lobBlockSize;
        this.fileName     = database.getPath() + ".lobs";

        try {
            boolean exists =
                database.logger.getFileAccess().isStreamElement(fileName);

            if (exists) {
                openFile();
            }
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    private void openFile() {

        try {
            boolean readonly = database.isFilesReadOnly();

            file = new RAFileSimple(database.logger, fileName, readonly ? "r"
                                                                        : "rws");
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public byte[] getBlockBytes(int blockAddress, int blockCount) {

        if (file == null) {
            throw Error.error(ErrorCode.FILE_IO_ERROR);
        }

        try {
            long   address   = (long) blockAddress * lobBlockSize;
            int    count     = blockCount * lobBlockSize;
            byte[] dataBytes = new byte[count];

            file.seek(address);
            file.read(dataBytes, 0, count);

            return dataBytes;
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public void setBlockBytes(byte[] dataBytes, int blockAddress,
                              int blockCount) {

        if (file == null) {
            openFile();
        }

        try {
            long address = (long) blockAddress * lobBlockSize;
            int  count   = blockCount * lobBlockSize;

            file.seek(address);
            file.write(dataBytes, 0, count);
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public void setBlockBytes(byte[] dataBytes, long position, int offset,
                              int length) {

        if (length == 0) {
            return;
        }

        if (file == null) {
            openFile();
        }

        try {
            file.seek(position);
            file.write(dataBytes, offset, length);
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public int getBlockSize() {
        return lobBlockSize;
    }

    public long getLength() {

        if (file == null) {
            openFile();
        }

        try {
            return file.length();
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public void setLength(long length) {

        try {
            if (file != null) {
                file.setLength(length);
                file.synch();
            }
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public void close() {

        try {
            if (file != null) {
                file.synch();
                file.close();
            }
        } catch (Throwable t) {
            throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
        }
    }

    public void synch() {

        if (file != null) {
            file.synch();
        }
    }
}