moved some files and fixed javadoc
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5 changed files with 147 additions and 20 deletions
219
src/zutil/io/BufferedRandomAccessFile.java
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219
src/zutil/io/BufferedRandomAccessFile.java
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package zutil.io;
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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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/**
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* This class is a buffer for the RandomeAccesFile
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* Inspiration:
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* http://www.javaworld.com/javaworld/javatips/jw-javatip26.html
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*
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* @author Ziver
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*/
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public class BufferedRandomAccessFile extends RandomAccessFile{
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// The size of the buffer
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private int BUF_SIZE = 256;
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// The Buffer
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byte buffer[];
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// The end of the buffer
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int buf_end = 0;
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// The position in the buffer
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int buf_pos = 0;
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// The real file pointer position where the buffer starts
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long file_pos = 0;
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/**
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* Create a instance of this buffer
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*
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* @param filename is the file to read from
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* @param mode as in {@link java.io.RandomAccessFile#RandomAccessFile(File file, String mode)}
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*/
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public BufferedRandomAccessFile(String filename, String mode) throws IOException{
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this(new File(filename), mode);
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}
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/**
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* Create a instance of this buffer
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*
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* @param file is the file to read from
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* @param mode as in {@link java.io.RandomAccessFile#RandomAccessFile(File file, String mode)}
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*/
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public BufferedRandomAccessFile(File file, String mode) throws IOException{
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super(file,mode);
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invalidate();
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buffer = new byte[BUF_SIZE];
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}
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/**
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* Create a instance of this buffer
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*
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* @param filename is the file to read from
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* @param mode as in {@link java.io.RandomAccessFile#RandomAccessFile(File file, String mode)}
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* @param bufsize is the buffer size in bytes
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* @throws IOException
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*/
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public BufferedRandomAccessFile(String filename, String mode, int bufsize) throws IOException{
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this(new File(filename), mode, bufsize);
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}
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/**
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* Create a instance of this buffer
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*
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* @param file is the file to read from
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* @param mode as in {@link java.io.RandomAccessFile#RandomAccessFile(File file, String mode)}
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* @param bufsize is the buffer size in bytes
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* @throws IOException
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*/
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public BufferedRandomAccessFile(File file, String mode, int bufsize) throws IOException{
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super(file,mode);
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invalidate();
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BUF_SIZE = bufsize;
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buffer = new byte[BUF_SIZE];
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}
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/**
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* @return the next byte in the buffer
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*/
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public final int read() throws IOException{
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if(buf_pos >= buf_end) {
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if(fillBuffer() < 0)
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return -1;
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}
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if(buf_end == 0) {
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return -1;
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} else {
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buf_pos++;
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return buffer[buf_pos-1];
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}
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}
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/**
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* Reads in data from the file to the buffer
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*
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* @return the buffer
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* @throws IOException
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*/
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private int fillBuffer() throws IOException {
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int n = super.read(buffer, 0, BUF_SIZE );
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if(n >= 0) {
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file_pos +=n;
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buf_end = n;
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buf_pos = 0;
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}
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return n;
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}
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/**
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* Resets the buffer
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*
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* @throws IOException
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*/
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private void invalidate() throws IOException {
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buf_end = 0;
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buf_pos = 0;
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file_pos = super.getFilePointer();
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}
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/**
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* Fills the given array with data from the buffer
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*
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* @param b is the array that will be filled
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* @return the amount of bytes read or -1 if eof
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*/
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public int read(byte b[]) throws IOException {
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return read(b, 0, b.length);
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}
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/**
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* Reads a given length of bytes from the buffer
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*
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* @param b is the array that will be filled
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* @param off is the offset in the array
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* @param len is the amount to read
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* @return the amount of bytes read or -1 if eof
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*/
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public int read(byte b[], int off, int len) throws IOException {
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int leftover = buf_end - buf_pos;
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if(len <= leftover) {
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System.arraycopy(buffer, buf_pos, b, off, len);
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buf_pos += len;
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return len;
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}
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for(int i = 0; i < len; i++) {
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int c = this.read();
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if(c != -1)
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b[off+i] = (byte)c;
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else {
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return i;
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}
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}
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return len;
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}
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/**
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* @return the file pointer in the file
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*/
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public long getFilePointer() throws IOException{
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long l = file_pos;
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return (l - buf_end + buf_pos) ;
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}
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/**
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* Changes the file pointer to another position
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*
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* @param pos The position to move the pointer to
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*/
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public void seek(long pos) throws IOException {
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int n = (int)(file_pos - pos);
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if(n >= 0 && n <= buf_end) {
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buf_pos = buf_end - n;
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} else {
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super.seek(pos);
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invalidate();
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}
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}
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/**
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* This method is a replacement for readLine()
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*
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* @return the next line in the file
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*/
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public final String readNextLine() throws IOException {
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String str = null;
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if(buf_end-buf_pos <= 0) {
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if(fillBuffer() < 0) {
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throw new IOException("Error filling buffer!");
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}
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}
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int lineend = -1;
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for(int i = buf_pos; i < buf_end; i++) {
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if(buffer[i] == '\n') {
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lineend = i;
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break;
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}
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}
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if(lineend < 0) {
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StringBuffer input = new StringBuffer(256);
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int c;
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while (((c = read()) != -1) && (c != '\n')) {
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input.append((char)c);
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}
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if ((c == -1) && (input.length() == 0)) {
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return null;
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}
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return input.toString();
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}
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if(lineend > 0 && buffer[lineend-1] == '\r'){
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str = new String(buffer, buf_pos, lineend - buf_pos -1);
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}
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else {
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str = new String(buffer, buf_pos, lineend - buf_pos);
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}
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buf_pos = lineend +1;
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return str;
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}
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}
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