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Benchmark for reading and parsing 10000000 integers
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package org.coursera.algs4partII002.perf; | |
import org.junit.Test; | |
import java.io.BufferedInputStream; | |
import java.io.BufferedReader; | |
import java.io.IOException; | |
import java.io.InputStreamReader; | |
import java.util.Scanner; | |
import java.util.StringTokenizer; | |
public class BufferedScannerPerfTest { | |
@Test | |
public void testScanner() { | |
Scanner scanner = new Scanner(new BufferedInputStream(getClass().getResourceAsStream("/integers.dat"))); | |
for (int i = 0; i < 10000000; i++) { | |
if (scanner.hasNext()) { | |
scanner.nextInt(); | |
} | |
} | |
} | |
@Test | |
public void testBufferedReader() throws IOException { | |
StringTokenizer stringTokenizer = new StringTokenizer("", "\n"); | |
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(getClass().getResourceAsStream("/integers.dat"))); | |
for (int i = 0; i < 10000000; i++) { | |
if (stringTokenizer.hasMoreTokens() != true) { | |
stringTokenizer = new StringTokenizer(bufferedReader.readLine()); | |
} | |
Integer.parseInt(stringTokenizer.nextToken()); | |
} | |
} | |
} | |
// +------------------+--------------+-------------+--------------+-------------+--------+ | |
// | Test | Time Elapsed | Usage Delta | Usage Before | Usage After | Result | | |
// +------------------+--------------+-------------+--------------+-------------+--------+ | |
// |testBufferedReader| 2s| 491,542 Kb| 4,377 Kb| 495,920 Kb| Passed| | |
// +------------------+--------------+-------------+--------------+-------------+--------+ | |
// | testScanner| 12s| 232,761 Kb| 495,920 Kb| 728,682 Kb| Passed| | |
// +------------------+--------------+-------------+--------------+-------------+--------+ |
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package org.coursera.algs4partII002.perf; | |
import org.junit.Test; | |
import java.io.*; | |
import java.util.Random; | |
import java.util.logging.Logger; | |
public class GenIntegers { | |
@Test | |
public void genIntegers() throws ClassNotFoundException, IOException { | |
Random random = new Random(System.currentTimeMillis()); | |
File integers = new File(Class.forName("org.coursera.algs4partII002.perf.BufferedScannerPerfTest").getResource("/").getPath() + "../../src/main/resources/integers.dat"); | |
Logger.getAnonymousLogger().info(integers.getAbsolutePath()); | |
if (integers.exists() == false) | |
integers.createNewFile(); | |
BufferedWriter outputStream = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(integers))); | |
for (int i = 0; i < 10000000; i++) { | |
int v = random.nextInt(); | |
if (v < 0) | |
v = -v; | |
outputStream.append(String.valueOf(v)); | |
outputStream.append("\n"); | |
} | |
outputStream.close(); | |
} | |
} |
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#include <cstdio> | |
int main(void) { | |
FILE *f = fopen("../../../target/classes/integers.dat", "r"); | |
int N = 10000000; | |
int n = 0; | |
for(int i = 0; i < N; i++) { | |
fscanf(f, "%d", &n); | |
} | |
return 0; | |
} | |
// $ gcc -o ReaderPerfTest -Wall -O3 ReaderPerfTest.cc | |
// $ time `./ReaderPerfTest.exe` | |
// | |
// real 0m4.873s | |
// user 0m4.664s | |
// sys 0m0.155s | |
// |
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