Revision: 5857
http://jnode.svn.sourceforge.net/jnode/?rev=5857&view=rev
Author: lsantha
Date: 2011-08-21 20:03:08 +0000 (Sun, 21 Aug 2011)
Log Message:
-----------
A RAMFile is stored in a list of Buffer object to support arbitrary large files.
Modified Paths:
--------------
trunk/fs/src/fs/org/jnode/fs/ramfs/RAMFile.java
Modified: trunk/fs/src/fs/org/jnode/fs/ramfs/RAMFile.java
===================================================================
--- trunk/fs/src/fs/org/jnode/fs/ramfs/RAMFile.java 2011-08-21 20:00:18 UTC
(rev 5856)
+++ trunk/fs/src/fs/org/jnode/fs/ramfs/RAMFile.java 2011-08-21 20:03:08 UTC
(rev 5857)
@@ -21,8 +21,11 @@
package org.jnode.fs.ramfs;
import java.io.IOException;
+import java.nio.BufferOverflowException;
+import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
+import java.util.ArrayList;
import org.jnode.fs.FSAccessRights;
import org.jnode.fs.FSDirectory;
import org.jnode.fs.FSEntry;
@@ -34,6 +37,7 @@
* A File implementation in the system RAM
*
* @author peda
+ * @author Levente S\u00e1ntha
*/
public class RAMFile implements FSEntry, FSFile {
@@ -41,7 +45,7 @@
private RAMDirectory parent;
private String filename;
- private ByteBuffer buffer;
+ private BufferList bufferList;
private long created;
private long lastModified;
@@ -63,42 +67,36 @@
// TODO accessRights
- buffer = ByteBuffer.allocate(128);
- buffer.limit(0);
+ bufferList = new BufferList();
fileSystem = (RAMFileSystem) parent.getFileSystem();
- fileSystem.addSummmedBufferSize(128);
+ fileSystem.addSummmedBufferSize(bufferList.capacity());
}
private void enlargeBuffer() throws FileSystemFullException {
- int oldCapacity = buffer.capacity();
+ int oldCapacity = bufferList.capacity();
if (oldCapacity > fileSystem.getFreeSpace())
throw new FileSystemFullException("RAMFileSystem reached maxSize");
- ByteBuffer temp = ByteBuffer.allocate(oldCapacity * 2);
- buffer.position(0);
- temp.put(buffer);
- buffer = temp;
- buffer.position(0);
+ bufferList.enlarge();
+ int newCapacity = bufferList.capacity();
// update fileSystem values
- fileSystem.addSummmedBufferSize(oldCapacity);
+ fileSystem.addSummmedBufferSize(newCapacity - oldCapacity);
}
private void shrinkBuffer() {
- int toShrink = buffer.capacity() / 2;
+ int oldCapacity = bufferList.capacity();
- ByteBuffer temp = ByteBuffer.allocate(toShrink);
- temp.put(buffer.array(), 0, toShrink);
- buffer = temp;
- buffer.position(0);
+ bufferList.shrink();
+ int newCapacity = bufferList.capacity();
// update fileSystem counter
- fileSystem.addSummmedBufferSize(-toShrink);
+ fileSystem.addSummmedBufferSize(newCapacity - oldCapacity);
}
/**
@@ -232,7 +230,7 @@
* @see org.jnode.fs.FSFile#getLength()
*/
public long getLength() {
- return buffer.limit();
+ return bufferList.limit();
}
/**
@@ -245,15 +243,15 @@
if (length > Integer.MAX_VALUE)
throw new IOException("Filesize too large");
- while (buffer.capacity() < length)
+ while (bufferList.capacity() < length)
enlargeBuffer();
- long toEnlarge = length - buffer.limit();
+ long toEnlarge = length - bufferList.limit();
- while (length < buffer.capacity() / 2)
+ while (length < bufferList.capacity() / 2)
shrinkBuffer();
- buffer.limit((int) length);
+ bufferList.limit((int) length);
// update fileSystem counters
fileSystem.addSummedFileSize(toEnlarge);
@@ -267,14 +265,14 @@
*/
public void read(long fileOffset, ByteBuffer dest) throws IOException {
- long currentSize = buffer.limit();
+ long currentSize = bufferList.limit();
long toRead = dest.limit();
if (fileOffset + toRead > currentSize)
throw new IOException("FileOffest outside file");
- buffer.position((int) fileOffset);
- buffer.get(dest.array(), 0, dest.limit());
+ bufferList.position((int) fileOffset);
+ bufferList.get(dest.array(), 0, dest.limit());
}
/**
@@ -284,14 +282,14 @@
*/
public void write(long fileOffset, ByteBuffer src) throws IOException {
- long currentSize = buffer.limit();
+ long currentSize = bufferList.limit();
long toWrite = src.limit();
if (fileOffset + toWrite >= currentSize)
setLength(fileOffset + toWrite);
- buffer.position((int) fileOffset);
- buffer.put(src);
+ bufferList.position((int) fileOffset);
+ bufferList.put(src);
setLastModified(System.currentTimeMillis());
}
@@ -305,13 +303,184 @@
void remove() throws IOException {
- long capacity = buffer.capacity();
+ long capacity = bufferList.capacity();
long filesize = getLength();
this.parent = null;
- this.buffer = null;
+ this.bufferList = null;
fileSystem.addSummedFileSize(-filesize);
fileSystem.addSummmedBufferSize(-capacity);
}
+
+ /**
+ * A resizing Buffer-like structure combining a set of NIO Buffers into
one entity.
+ *
+ * @author Levente S\u00e1ntha
+ */
+ private static class BufferList {
+ private static final int MAX_BUFFER_SIZE = 12 * 1024 * 1024;
+ private final ArrayList<ByteBuffer> bufferList;
+
+ BufferList() {
+ bufferList = new ArrayList<ByteBuffer>();
+ ByteBuffer buffer = ByteBuffer.allocate(128);
+ buffer.limit(0);
+ bufferList.add(buffer);
+ }
+
+ private void enlarge() {
+ int oldCapacity = capacity();
+ if (bufferList.size() == 1) {
+ final ByteBuffer oldBuffer = bufferList.get(0);
+ final int newCapacity = oldCapacity * 2;
+ bufferList.clear();
+ if (newCapacity > MAX_BUFFER_SIZE) {
+ final ByteBuffer newBuffer =
ByteBuffer.allocate(MAX_BUFFER_SIZE);
+ oldBuffer.position(0);
+ newBuffer.put(oldBuffer);
+ newBuffer.position(0);
+
+ bufferList.add(newBuffer);
+ bufferList.add(ByteBuffer.allocate(newCapacity -
MAX_BUFFER_SIZE));
+ } else {
+ ByteBuffer buffer2 = ByteBuffer.allocate(newCapacity);
+ oldBuffer.position(0);
+ buffer2.put(oldBuffer);
+ buffer2.position(0);
+
+ bufferList.add(buffer2);
+ }
+ } else {
+ bufferList.add(ByteBuffer.allocate(MAX_BUFFER_SIZE));
+ }
+ }
+
+ private void shrink() {
+ final int oldCapacity = capacity();
+ if (bufferList.size() == 1) {
+ final ByteBuffer oldBuffer = bufferList.get(0);
+ final int newCapacity = oldCapacity / 2;
+ bufferList.clear();
+
+ final ByteBuffer newBuffer = ByteBuffer.allocate(newCapacity);
+ oldBuffer.position(0);
+ oldBuffer.limit(newCapacity);
+ newBuffer.put(oldBuffer);
+ newBuffer.position(0);
+
+ bufferList.add(newBuffer);
+ } else {
+ bufferList.remove(bufferList.size() - 1);
+ }
+ }
+
+ private int capacity() {
+ int capacity = 0;
+ for (ByteBuffer buffer : bufferList) {
+ capacity += buffer.capacity();
+ }
+ return capacity;
+ }
+
+ private int limit() {
+ int limit = 0;
+ for (ByteBuffer buffer : bufferList) {
+ limit += buffer.limit();
+ }
+ return limit;
+ }
+
+ private void limit(int limit) {
+ for (ByteBuffer buffer : bufferList) {
+ if (limit < 0) {
+ buffer.limit(0);
+ } else {
+ int capacity = buffer.capacity();
+ if (limit <= capacity) {
+ buffer.limit(limit);
+ } else {
+ buffer.limit(capacity);
+ }
+ limit -= capacity;
+ }
+ }
+ }
+
+ private int position() {
+ int position = 0;
+ for (ByteBuffer buffer : bufferList) {
+ position += buffer.position();
+ }
+ return position;
+ }
+
+ public void position(int position) {
+ for (ByteBuffer buffer : bufferList) {
+ if (position < 0) {
+ buffer.position(0);
+ } else {
+ int limit = buffer.limit();
+ if (position <= limit) {
+ buffer.position(position);
+ } else {
+ buffer.position(limit);
+ }
+ position -= limit;
+ }
+ }
+ }
+
+ public int remaining() {
+ int remaining = 0;
+ for (ByteBuffer buffer : bufferList) {
+ remaining += buffer.remaining();
+ }
+ return remaining;
+ }
+
+ public void get(byte[] array, int offset, int length) {
+
+ if ((offset | length | (offset + length) | (array.length - (offset
+ length))) < 0)
+ throw new IndexOutOfBoundsException();
+
+ if (length > remaining())
+ throw new BufferUnderflowException();
+
+ for (ByteBuffer buffer : bufferList) {
+ int remaining = buffer.remaining();
+ if (remaining > 0) {
+ if (length > remaining) {
+ buffer.get(array, offset, remaining);
+ offset += remaining;
+ length -= remaining;
+ } else {
+ buffer.get(array, offset, length);
+ return;
+ }
+ }
+ }
+ }
+
+ public void put(ByteBuffer src) {
+ int length = src.remaining();
+ if (length > remaining())
+ throw new BufferOverflowException();
+
+ for (ByteBuffer buffer : bufferList) {
+ int remaining = buffer.remaining();
+ if (remaining > 0) {
+ if (length > remaining) {
+ src.limit(src.position() + remaining);
+ buffer.put(src);
+ length -= remaining;
+ } else {
+ src.limit(src.position() + length);
+ buffer.put(src);
+ return;
+ }
+ }
+ }
+ }
+ }
}
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