FWD » Core Development » Base Language

import java.io.*;

import java.util.*;

import java.security.*;

public class StringGenerator

{

   private static SecureRandom random = new SecureRandom();

   public static void writeRecord(OutputStream out, int[] data)

   throws IOException

   {

      out.write(data.length);

      for (int i = 0; i < data.length; i++)

      {

         out.write(data[i]);

      }

   }

   public static int[] genRandomUnsignedBytes(int len)

   throws IOException

   {

      int[] result = new int[len];

      for (int i = 0; i < len; i++)

      {

         result[i] = random.nextInt(256);

         if (result[i] < 0 || result[i] > 255)

            throw new IllegalStateException("found invalid int " + result[i]);

      }

      return result;

   }

   private static class IntArrayHolder

   implements Comparable

   {

      int[] data = null;

      public IntArrayHolder(int[] data)

      {

         this.data = data;

      }

      public int compareTo(Object other)

      {

         if (other == null)

            throw new NullPointerException();

         IntArrayHolder oth = (IntArrayHolder) other;

         int result = 0;

         if (data.length == oth.data.length)

         {

            // compare contents, lowest element to highest element

            for (int i = 0; i < data.length; i++)

            {

               if (data[i] == oth.data.length)

               {

                  continue;

               }

               else

               {

                  // first differing element determines the result

                  result = (data[i] > oth.data[i]) ? 1 : -1;

               }

            }

            // result stays as 0, nothing to do since they are equal

         }

         else

         {

            result = (data.length > oth.data.length) ? 1 : -1;

         }

         return result;

      }

      public boolean equals(Object other)

      {

         if (!(other instanceof IntArrayHolder))

            return false;

         return this.compareTo((IntArrayHolder) other) == 0;

      }

      public int hashCode()

      {

         return Arrays.hashCode(data);

      }

   }

   public static void main(String[] args)

   {

      OutputStream out  = null;

      int[] data = null;

      try

      {

         out = new FileOutputStream(args[1]);

         if ("-r".equalsIgnoreCase(args[0]))

         {

            for (int j = 3; j < 33; j++)

            {

               TreeSet<IntArrayHolder> set = new TreeSet<IntArrayHolder>();

               while (set.size() < 10000)

               {

                  set.add(new IntArrayHolder(genRandomUnsignedBytes(j)));

               }

               Iterator<IntArrayHolder> iter = set.iterator();

               while (iter.hasNext())

               {

                  writeRecord(out, iter.next().data);

               }

            }

         }

         else

         {

            // empty string

            data = new int[0];

            writeRecord(out, data);

            // all possible 1 character strings

            data = new int[1];

            for (int n = 0; n < 256; n++)

            {

               data[0] = n;

               writeRecord(out, data);

            }

            // all possible 2 character strings

            data = new int[2];

            for (int i = 0; i < 256; i++)

            {

               data[0] = i;

               for (int j = 0; j < 256; j++)

               {

                  data[1] = j;

                  writeRecord(out, data);

               }

            }

         }

      }

      catch (IOException ioe)

      {

         ioe.printStackTrace();

      }

      finally

      {

         try

         {

            if (out != null)

               out.close();

         }

         catch (IOException ioe)

         {

            // ignore

         }

      }

   }

}