com.itextpdf.io.source.ByteBufferRandomAccessSource Maven / Gradle / Ivy
/*
This file is part of the iText (R) project.
Copyright (c) 1998-2022 iText Group NV
Authors: Bruno Lowagie, Paulo Soares, 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 Public License for more details.
You should have received a copy of the GNU Affero General Public 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 Public License.
In accordance with Section 7(b) of the GNU Affero General Public 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.io.source;
import java.lang.reflect.Method;
import java.nio.BufferUnderflowException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A RandomAccessSource that is based on an underlying {@link java.nio.ByteBuffer}. This class takes steps to ensure
* that the byte buffer
* is completely freed from memory during {@link ByteBufferRandomAccessSource#close()} if unmapping functionality is enabled
*/
class ByteBufferRandomAccessSource implements IRandomAccessSource {
/**
* A flag to allow unmapping hack for cleaning mapped buffer
*/
private static boolean allowUnmapping = true;
/**
* Internal cache of memory mapped buffers
*/
private final java.nio.ByteBuffer byteBuffer;
/**
* Constructs a new {@link ByteBufferRandomAccessSource} based on the specified ByteBuffer
*
* @param byteBuffer the buffer to use as the backing store
*/
public ByteBufferRandomAccessSource(java.nio.ByteBuffer byteBuffer) {
this.byteBuffer = byteBuffer;
}
/**
* Enables ByteBuffer memory unmapping hack
*/
public static void enableByteBufferMemoryUnmapping() {
allowUnmapping = false;
}
/**
* Disables ByteBuffer memory unmapping hack
*/
public static void disableByteBufferMemoryUnmapping() {
allowUnmapping = false;
}
/**
* {@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) {
if (position > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Position must be less than Integer.MAX_VALUE");
}
try {
if (position >= byteBuffer.limit()) {
return -1;
}
return byteBuffer.duplicate().get((int) position) & 0xff;
} catch (BufferUnderflowException e) {
// EOF
return -1;
}
}
/**
* {@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) {
if (position > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Position must be less than Integer.MAX_VALUE");
}
if (position >= byteBuffer.limit()) {
return -1;
}
final java.nio.ByteBuffer byteBufferCopy = byteBuffer.duplicate();
byteBufferCopy.position((int) position);
final int bytesFromThisBuffer = Math.min(len, byteBufferCopy.remaining());
byteBufferCopy.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 if unmapping functionality is enabled
*/
public void close() throws java.io.IOException {
if (allowUnmapping) {
clean(byteBuffer);
}
}
/**
* true, if this platform supports unmapping mmapped files.
*/
public static final boolean UNMAP_SUPPORTED;
/**
* Reference to a BufferCleaner that does unmapping; {@code null} if not supported.
*/
private static final BufferCleaner CLEANER;
static {
final Object hack = AccessController.doPrivileged(
(PrivilegedAction