svn commit: r1878359 - /pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java

[le...@apache.org]

Author: lehmi
Date: Mon Jun  1 12:11:12 2020
New Revision: 1878359

URL: http://svn.apache.org/viewvc?rev=1878359&view=rev
Log:
PDFBOX-4855: add an implementation of RandomAccessRead using memory mapped file reading

Added:
    pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java   (with props)

Added: pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java
URL: http://svn.apache.org/viewvc/pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java?rev=1878359&view=auto
==============================================================================
--- pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java (added)
+++ pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java Mon Jun  1 12:11:12 2020
@@ -0,0 +1,213 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.pdfbox.io;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.file.StandardOpenOption;
+import java.util.EnumSet;
+
+/**
+ * An implementation of the RandomAccess interface backed by a memory mapped file channel. The whole file is mapped to
+ * memory and the max size is limited to Integer.MAX_VALUE.
+ */
+public class RandomAccessReadMemoryMappedFile implements RandomAccessRead
+{
+
+    // mapped byte buffer
+    private MappedByteBuffer mappedByteBuffer;
+
+    // size of the whole file
+    private final long size;
+
+    // file channel of the file to be read
+    private final FileChannel fileChannel;
+
+    /**
+     * Default constructor.
+     */
+    public RandomAccessReadMemoryMappedFile(String filename) throws IOException
+    {
+        this(new File(filename));
+    }
+
+    /**
+     * Default constructor.
+     */
+    public RandomAccessReadMemoryMappedFile(File file) throws IOException
+    {
+        fileChannel = FileChannel.open(file.toPath(), EnumSet.of(StandardOpenOption.READ));
+        size = fileChannel.size();
+        // TODO only ints are allowed -> implement paging
+        if (size > Integer.MAX_VALUE)
+        {
+            throw new IOException(getClass().getName()
+                    + " doesn't yet support files bigger than "
+                    + Integer.MAX_VALUE);
+        }
+        // map the whole file to memory
+        mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, size);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void close() throws IOException
+    {
+        fileChannel.close();
+        mappedByteBuffer = null;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void seek(long position) throws IOException
+    {
+        checkClosed();
+        if (position < 0)
+        {
+            throw new IOException("Invalid position "+position);
+        }
+        mappedByteBuffer.position((int) position);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public long getPosition() throws IOException
+    {
+       checkClosed();
+       return mappedByteBuffer.position();
+    }
+    
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public int read() throws IOException
+    {
+        if (isEOF())
+        {
+            return -1;
+        }
+        return mappedByteBuffer.get() & 0xff;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public int read(byte[] b, int offset, int length) throws IOException
+    {
+        if (isEOF())
+        {
+            return 0;
+        }
+        int remainingBytes = (int)size - mappedByteBuffer.position();
+        mappedByteBuffer.get(b, offset, Math.min(remainingBytes, length));
+        return Math.min(remainingBytes, length);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public long length() throws IOException
+    {
+        checkClosed();
+        return size;
+    }
+
+    /**
+     * Ensure that the RandomAccessReadMemoryMappedFile is not closed
+     * 
+     * @throws IOException
+     */
+    private void checkClosed() throws IOException
+    {
+        if (isClosed())
+        {
+            throw new IOException(getClass().getSimpleName() + " already closed");
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean isClosed()
+    {
+        return !fileChannel.isOpen();
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean isEOF() throws IOException
+    {
+        checkClosed();
+        return mappedByteBuffer.position() >= size;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public int available() throws IOException
+    {
+        return (int) Math.min(length() - getPosition(), Integer.MAX_VALUE);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public int peek() throws IOException
+    {
+        int result = read();
+        if (result != -1)
+        {
+            rewind(1);
+        }
+        return result;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public void rewind(int bytes) throws IOException
+    {
+        checkClosed();
+        seek(getPosition() - bytes);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public int read(byte[] b) throws IOException
+    {
+        return read(b, 0, b.length);
+    }
+}

Propchange: pdfbox/trunk/pdfbox/src/main/java/org/apache/pdfbox/io/RandomAccessReadMemoryMappedFile.java
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