87 lines
2.6 KiB
Java
87 lines
2.6 KiB
Java
package moe.nekojimi.friendcloud;
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import moe.nekojimi.friendcloud.objects.NetworkFile;
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import java.io.Closeable;
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import java.io.File;
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import java.io.IOException;
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import java.io.RandomAccessFile;
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public class FilePieceAccess implements Closeable
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{
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private final NetworkFile networkFile;
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private final File file;
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private final RandomAccessFile randomAccessFile;
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private final OpenMode openMode;
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public FilePieceAccess(NetworkFile networkFile, OpenMode openMode) throws IOException
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{
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this.networkFile = networkFile;
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this.file = networkFile.getOrCreateLocalFile();
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this.randomAccessFile = new RandomAccessFile(file,openMode == OpenMode.READ_WRITE ? "rw" : "r");
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this.openMode = openMode;
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if (openMode == OpenMode.READ_WRITE)
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randomAccessFile.setLength(file.length());
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}
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public long getPieceOffset(int index)
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{
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return (index * networkFile.getPieceSize());
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}
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public int getPieceSize(int index)
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{
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if (index != networkFile.getPieceCount()-1)
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return Math.toIntExact(networkFile.getPieceSize());
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int ret = Math.toIntExact(networkFile.getSize() % networkFile.getPieceSize());
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if (ret == 0)
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ret = Math.toIntExact(networkFile.getPieceSize());
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return ret;
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}
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public byte[] readPiece(int index) throws IOException
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{
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if (index >= networkFile.getPieceCount())
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throw new IllegalArgumentException("Piece index out of range!!");
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if (index < 0)
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throw new IllegalArgumentException("Piece index is negative!!");
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if (!networkFile.hasPiece(index))
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return null;
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int pieceSize = getPieceSize(index);
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byte[] buffer = new byte[pieceSize];
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long pieceOffset = getPieceOffset(index);
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System.out.println("Reading piece " + index + " from file " + file.getName() + " (offset=" + pieceOffset + ", size=" + pieceSize + ")");
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randomAccessFile.seek(pieceOffset);
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randomAccessFile.read(buffer);
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return buffer;
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}
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public void writePiece(int index, byte[] buffer) throws IOException
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{
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if (openMode == OpenMode.READ_ONLY)
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throw new IllegalStateException("File was opened read-only!");
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else if (buffer.length != getPieceSize(index))
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throw new IllegalArgumentException("Received a file piece that's the wrong size!! Length = " + buffer.length + " != Piece Size = " + getPieceSize(index));
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else if (index >= networkFile.getPieceCount())
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throw new IllegalArgumentException("Received a file piece with an index past the end of the file!!");
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randomAccessFile.seek(getPieceOffset(index));
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randomAccessFile.write(buffer);
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networkFile.setHasPiece(index, true);
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}
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@Override
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public void close() throws IOException
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{
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randomAccessFile.close();
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}
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public enum OpenMode
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{
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READ_ONLY,
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READ_WRITE;
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}
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}
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