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HSQLDB - Lightweight 100% Java SQL Database Engine
/* Copyright (c) 2001-2021, 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;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb.persist;
import java.io.DataInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import org.hsqldb.Database;
import org.hsqldb.lib.HsqlByteArrayInputStream;
/**
* This class is a random access wrapper around a DataInputStream object and
* enables access to cached tables when a database is included in a jar.
*
* A proof-of-concept prototype was first contributed by winfriedthom@users.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.3.0
* @since 1.8.0
*/
final class RAFileInJar implements RandomAccessInterface {
DataInputStream file;
final String fileName;
long fileLength;
boolean bufferDirty = true;
byte[] buffer = new byte[4096];
HsqlByteArrayInputStream ba = new HsqlByteArrayInputStream(buffer);
long bufferOffset;
//
long seekPosition;
long realPosition;
RAFileInJar(String name) throws FileNotFoundException, IOException {
fileName = name;
fileLength = getLength();
resetStream();
}
public long length() {
return fileLength;
}
/**
* Some JVM's do not allow seek beyond end of file, so zeros are written
* first in that case. Reported by bohgammer@users in Open Disucssion
* Forum.
*/
public void seek(long position) {
seekPosition = position;
}
public long getFilePointer() {
return seekPosition;
}
private void readIntoBuffer() throws IOException {
long filePos = seekPosition;
bufferDirty = false;
long subOffset = filePos % buffer.length;
long readLength = fileLength - (filePos - subOffset);
if (readLength <= 0) {
throw new IOException("read beyond end of file");
}
if (readLength > buffer.length) {
readLength = buffer.length;
}
fileSeek(filePos - subOffset);
file.readFully(buffer, 0, (int) readLength);
bufferOffset = filePos - subOffset;
realPosition = bufferOffset + readLength;
}
public int read() throws IOException {
if (seekPosition >= fileLength) {
return -1;
}
if (bufferDirty || seekPosition < bufferOffset
|| seekPosition >= bufferOffset + buffer.length) {
readIntoBuffer();
}
ba.reset();
ba.skip(seekPosition - bufferOffset);
int val = ba.read();
seekPosition++;
return val;
}
public long readLong() throws IOException {
long hi = readInt();
long lo = readInt();
return (hi << 32) + (lo & 0xffffffffL);
}
public int readInt() throws IOException {
if (bufferDirty || seekPosition < bufferOffset
|| seekPosition >= bufferOffset + buffer.length) {
readIntoBuffer();
}
ba.reset();
ba.skip(seekPosition - bufferOffset);
int val = ba.readInt();
seekPosition += 4;
return val;
}
public void read(byte[] b, int offset, int length) throws IOException {
if (bufferDirty || seekPosition < bufferOffset
|| seekPosition >= bufferOffset + buffer.length) {
readIntoBuffer();
}
ba.reset();
ba.skip(seekPosition - bufferOffset);
int bytesRead = ba.read(b, offset, length);
seekPosition += bytesRead;
if (bytesRead < length) {
if (seekPosition != realPosition) {
fileSeek(seekPosition);
}
file.readFully(b, offset + bytesRead, length - bytesRead);
seekPosition += (length - bytesRead);
realPosition = seekPosition;
}
}
public void write(byte[] b, int off, int len) {}
public void writeInt(int i) {}
public void writeLong(long i) {}
public void close() throws IOException {
file.close();
}
public boolean isReadOnly() {
return true;
}
private long getLength() throws IOException {
int count = 0;
resetStream();
while (true) {
if (file.read() < 0) {
break;
}
count++;
}
return count;
}
private void resetStream() throws IOException {
if (file != null) {
file.close();
}
InputStream fis = null;
try {
fis = getClass().getResourceAsStream(fileName);
if (fis == null) {
ClassLoader cl =
Thread.currentThread().getContextClassLoader();
if (cl != null) {
fis = cl.getResourceAsStream(fileName);
}
}
} catch (Throwable t) {
//
} finally {
if (fis == null) {
throw new FileNotFoundException(fileName);
}
}
file = new DataInputStream(fis);
}
private void fileSeek(long position) throws IOException {
long skipPosition = realPosition;
if (position < skipPosition) {
resetStream();
skipPosition = 0;
}
while (position > skipPosition) {
skipPosition += file.skip(position - skipPosition);
}
}
public boolean ensureLength(long newLong) {
return true;
}
public boolean setLength(long newLength) {
return false;
}
public Database getDatabase() {
return null;
}
public void synch() {}
}