/* Copyright (c) 2001-2009, 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.jdbc;
import java.io.IOException;
import java.io.Reader;
import java.sql.SQLException;
import org.hsqldb.Error;
import org.hsqldb.ErrorCode;
/**
* This class is used as an InputStream to retrieve data from a Blob.
* mark() and reset() are not supported.
*
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 1.9.0
* @since 1.9.0
*/
public final class ClobInputStream extends Reader {
final JDBCClobClient clob;
final long availableLength;
long bufferOffset;
long currentPosition;
char[] buffer;
boolean isClosed;
int streamBlockSize;
public ClobInputStream(JDBCClobClient clob, long offset, long length,
int blockSize) throws SQLException {
if (!JDBCClobClient.isInLimits(clob.length(), offset, length)) {
throw Util.outOfRangeArgument();
}
this.clob = clob;
this.availableLength = offset + length;
this.currentPosition = offset;
this.streamBlockSize = blockSize;
}
public int read() throws IOException {
checkClosed();
if (currentPosition >= availableLength) {
return -1;
}
if (buffer == null
|| currentPosition >= bufferOffset + buffer.length) {
try {
readIntoBuffer();
} catch (SQLException e) {
throw new IOException(e.getMessage());
}
}
int val = buffer[(int) (currentPosition - bufferOffset)] & 0xff;
currentPosition++;
return val;
}
public int read(char[] cbuf, int off, int len) throws IOException {
checkClosed();
if (currentPosition + len >= availableLength) {
return -1;
}
for (int i = off; i < len; i++) {
cbuf[i] = (char) read();
}
return len;
}
public long skip(long n) throws IOException {
checkClosed();
if (n <= 0) {
return 0;
}
if (currentPosition + n > availableLength) {
n = availableLength - currentPosition;
}
currentPosition += n;
return n;
}
public int available() throws IOException {
return (int) (bufferOffset + buffer.length - currentPosition);
}
public void close() throws IOException {
isClosed = true;
}
private void checkClosed() throws IOException {
if (isClosed || clob.isClosed()) {
throw new IOException(
Error.getMessage(ErrorCode.X_0F503));
}
}
private void readIntoBuffer() throws SQLException {
long readLength = availableLength - currentPosition;
if (readLength <= 0) {}
if (readLength > streamBlockSize) {
readLength = streamBlockSize;
}
buffer = clob.getChars(currentPosition, (int) readLength);
bufferOffset = currentPosition;
}
}