public class ArrayCopyTest {

  static final int N = 100000;

  static void test(byte a1[], byte a2[], int from[], int to[],
                  int iter, int start, int limit, int step) {
    int res = 0;
    for (int size = start; size <= limit; size += step) {
      long begin_time = System.currentTimeMillis();
      for (int j = 0; j < iter; j++) {
        for (int k = 1; k < N; k++) {
          System.arraycopy(a1, to[k], a2, from[k], size);
          res += a1[size];
        }
      }
      long end_time = System.currentTimeMillis();
      System.out.println("'" + size + "," + (end_time-begin_time));
    }
    System.out.println("result = " + res);
  }
  
  public static void main (String[] args) {

    final int ARRSIZE = 128 * 1024;

    byte arr1[] = new byte[ARRSIZE * 2];
    byte arr2[] = new byte[ARRSIZE * 2];
    int from[] = new int[N];
    int to[] = new int[N];

    int f1 = 1, f2 = 1;
    for (int i = 0; i < ARRSIZE * 2; i++) {
      int n = f1 + f2;
      arr1[i] = (byte)n;
      arr2[i] = (byte)f1;
      f1 = f2; f2 = n;
    }

    java.util.Random gen = new java.util.Random(1L);

    for (int i = 0; i < N; i++) {
      from[i] = (int)(gen.nextDouble() * (double)ARRSIZE);
    }

    for (int i = 0; i < N; i++) {
      to[i] = (int)(gen.nextDouble() * (double)ARRSIZE);
    }

    int iter = Integer.parseInt(args[0]);
    int start = Integer.parseInt(args[1]);
    int end = Integer.parseInt(args[2]);
    int step = Integer.parseInt(args[3]);

    System.out.println("Warmup");
    test(arr1, arr2, from, to, 10, 0, 1000, 100);
    test(arr2, arr1, from, to, 10, 0, 1000, 100);

    System.out.println("Testing copies from size = " + start + " to " + end + ", step = " + step);
    System.out.println("=========================================================");
    test(arr1, arr2, from, to, iter, start, end, step);
    System.out.println("Testing reverse copies from size = " + start + " to " + end + ", step = " + step);
    test(arr2, arr1, from, to, iter, start, end, step);
    System.out.println("=========================================================");
  }
}