94 lines
2.7 KiB
Java
94 lines
2.7 KiB
Java
import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.nio.CharBuffer;
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import java.nio.channels.AsynchronousFileChannel;
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import java.nio.channels.CompletionHandler;
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import java.nio.charset.Charset;
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import java.nio.file.OpenOption;
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import java.nio.file.Path;
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import java.nio.file.Paths;
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import java.nio.file.StandardOpenOption;
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import java.util.concurrent.Semaphore;
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/**
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*
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*/
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/**
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* @author KAJE
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*
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*/
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public class NioLineCount {
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static int theCount = 0;
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// A 0 means that you will be waited until signalled
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static Semaphore partialReadGate = new Semaphore(1);
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static boolean doContinue = true;
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static long readPosition = 0;
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private static int lineCount(String thePath, boolean doDance){
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if ( ! doDance ) return -1;
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ByteBuffer buffer = ByteBuffer.allocate(1024);
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Path myPath = Paths.get( thePath );
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try {
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AsynchronousFileChannel fileChannel = AsynchronousFileChannel.open(myPath, StandardOpenOption.READ);
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while ( doContinue ) {
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try {
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// In the end we will be waiting here
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partialReadGate.acquire();
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if ( ! doContinue ) return theCount;
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} catch (InterruptedException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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fileChannel.read(buffer, readPosition, buffer, new CompletionHandler<Integer,ByteBuffer>() {
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@Override
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public void completed(Integer result, ByteBuffer attachment) {
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// System.out.println("Result = " + result + " Limit = " + attachment.limit());
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if ( result != -1 ) {
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attachment.flip();
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byte[] data = new byte[attachment.limit()];
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attachment.get( data );
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//System.out.println(new String(data));
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for (int i = 0; i < data.length; i++ ) {
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if ( data[i] == '\n' )
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theCount++;
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//System.out.println("data: " + data[i]);
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}
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// System.out.println("position: " + readPosition + " Count: " + theCount);
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readPosition += data.length;
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attachment.clear();
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} else {
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doContinue = false;
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}
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partialReadGate.release();
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}
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@Override
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public void failed(Throwable exc, ByteBuffer attachment) {
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}
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});
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}
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} catch (IOException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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return theCount;
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}
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/**
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* @param args
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*/
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public static void main(String[] args){
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long startTime = System.nanoTime();
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lineCount("", false);
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long dryRun = System.nanoTime() - startTime;
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startTime = System.nanoTime();
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int lines = lineCount("input.txt", true);
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long stopTime = System.nanoTime();
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System.out.println("Lines: " + String.valueOf(lines));
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System.out.println("Time it took: " + (stopTime - startTime - dryRun) + " " + dryRun);
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}
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}
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