/* Copied from https://llvm.org/svn/llvm-project/test-suite/tags/RELEASE_14/SingleSource/Benchmarks
 * License: LLVM Release License. See Notice file
 */

package org.linaro.benchmarks.stanford;

import org.openjdk.jmh.annotations.*;
import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@State(Scope.Benchmark)

public class Perm {

  private static final int permrange = 10;

  private boolean error;

  /* Perm */
  private int[] permarray = new int [permrange + 1];
  /* converted pctr to unsigned int for 16 bit WR*/
  private int  pctr;

// CHECKSTYLE.OFF: .*
    /* Permutation program, heavily recursive, written by Denny Brown. */
void Swap ( int a[], int ai,  int b[], int bi ) {
	int t;
	t = a[ai];  a[ai] = b[bi];  b[bi] = t;
}

void Initialize () {
	int i;
	for ( i = 1; i <= 7; i++ ) {
	    permarray[i]=i-1;
	}
}

void Permute (int n) {   /* permute */
	int k;
	pctr = pctr + 1;
	if ( n!=1 )  {
	    Permute(n-1);
	    for ( k = n-1; k >= 1; k-- ) {
			Swap(permarray, n, permarray, k);
			Permute(n-1);
			Swap(permarray, n, permarray, k);
		}
    }
}     /* permute */

void Perm ()    {   /* Perm */
    int i;
    pctr = 0;
    for ( i = 1; i <= 5; i++ ) {
		Initialize();
		Permute(7);
	}
    if ( pctr != 43300 )
	error = true;
}     /* Perm */
  // CHECKSTYLE.ON: .*

  @Benchmark
  public void jmhTimePerm() {
    Perm();
  }
}