com.itextpdf.text.io.ByteBufferRandomAccessSource Maven / Gradle / Ivy
/*
*
* This file is part of the iText (R) project.
Copyright (c) 1998-2019 iText Group NV
* Authors: Kevin Day, Bruno Lowagie, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
* ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
* OF THIRD PARTY RIGHTS.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Affero General License for more
* details. You should have received a copy of the GNU Affero General License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General License.
*
* In accordance with Section 7(b) of the GNU Affero General License, a covered
* work must retain the producer line in every PDF that is created or
* manipulated using iText.
*
* You can be released from the requirements of the license by purchasing a
* commercial license. Buying such a license is mandatory as soon as you develop
* commercial activities involving the iText software without disclosing the
* source code of your own applications. These activities include: offering paid
* services to customers as an ASP, serving PDFs on the fly in a web
* application, shipping iText with a closed source product.
*
* For more information, please contact iText Software Corp. at this address:
* [email protected]
*/
package com.itextpdf.text.io;
import java.io.IOException;
import java.lang.reflect.Method;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* A RandomAccessSource that is based on an underlying {@link ByteBuffer}. This class takes steps to ensure that the byte buffer
* is completely freed from memory during {@link ByteBufferRandomAccessSource#close()}
* @since 5.3.5
*/
class ByteBufferRandomAccessSource implements RandomAccessSource {
/**
* Internal cache of memory mapped buffers
*/
private final ByteBuffer byteBuffer;
/**
* Constructs a new {@link ByteBufferRandomAccessSource} based on the specified ByteBuffer
* @param byteBuffer the buffer to use as the backing store
*/
public ByteBufferRandomAccessSource(final ByteBuffer byteBuffer) {
this.byteBuffer = byteBuffer;
}
/**
* {@inheritDoc}
*
* Note: Because ByteBuffers don't support long indexing, the position must be a valid positive int
* @param position the position to read the byte from - must be less than Integer.MAX_VALUE
*/
public int get(long position) throws IOException {
if (position > Integer.MAX_VALUE)
throw new IllegalArgumentException("Position must be less than Integer.MAX_VALUE");
try {
if (position >= byteBuffer.limit())
return -1;
byte b = byteBuffer.get((int)position);
int n = b & 0xff;
return n;
} catch (BufferUnderflowException e) {
return -1; // EOF
}
}
/**
* {@inheritDoc}
*
* Note: Because ByteBuffers don't support long indexing, the position must be a valid positive int
* @param position the position to read the byte from - must be less than Integer.MAX_VALUE
*/
public int get(long position, byte[] bytes, int off, int len) throws IOException {
if (position > Integer.MAX_VALUE)
throw new IllegalArgumentException("Position must be less than Integer.MAX_VALUE");
if (position >= byteBuffer.limit())
return -1;
byteBuffer.position((int)position);
int bytesFromThisBuffer = Math.min(len, byteBuffer.remaining());
byteBuffer.get(bytes, off, bytesFromThisBuffer);
return bytesFromThisBuffer;
}
/**
* {@inheritDoc}
*/
public long length() {
return byteBuffer.limit();
}
/**
* @see java.io.RandomAccessFile#close()
* Cleans the mapped bytebuffers and closes the channel
*/
public void close() throws IOException {
clean(byteBuffer);
}
/**
* invokes the clean method on the ByteBuffer's cleaner
* @param buffer ByteBuffer
* @return boolean true on success
*/
private static boolean clean(final java.nio.ByteBuffer buffer) {
if (buffer == null || !buffer.isDirect())
return false;
Boolean b = (Boolean) AccessController.doPrivileged(new PrivilegedAction() {
public Boolean run() {
Boolean success = Boolean.FALSE;
try {
Method getCleanerMethod = buffer.getClass().getMethod("cleaner", (Class[])null);
getCleanerMethod.setAccessible(true);
Object cleaner = getCleanerMethod.invoke(buffer, (Object[])null);
Method clean = cleaner.getClass().getMethod("clean", (Class[])null);
clean.invoke(cleaner, (Object[])null);
success = Boolean.TRUE;
} catch (Exception e) {
// This really is a show stopper on windows
//e.printStackTrace();
}
return success;
}
});
return b.booleanValue();
}
}