--- a/progs/catastrophic.java Thu Dec 06 22:51:46 2018 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,40 +0,0 @@
-// a case of catastrophic backtracking in Java
-//
-// regexp: (a*)*b
-// strings: aa....
-
-import java.util.regex.*;
-
-public class catastrophic {
- public static void main(String[] args) {
-
- //we always run all the tests twice -> warmup of the JVM
- for (int runs = 0; runs < 3; runs++) {
-
- Pattern pattern = Pattern.compile("(a*)*b");
-
- // Run from 5 to 28 characters
- for (int length = 70000; length < 70001; length++) {
-
- // Build input of specified length
- String input = "";
- for (int i = 0; i < length; i++) { input += "a"; }
-
- // Measure the average duration of two calls...
- long start = System.nanoTime();
- for (int i = 0; i < 2; i++) {
- pattern.matcher(input).find();
- }
-
- System.out.println(length + " " + input + ": "
- + ((System.nanoTime() - start) / 3000000000d)
- + "s");
- }
- }
- }
-}
-
-
-
-// javac catastrophic.java
-// java catastrophic