package jalview.util;


public class StringUtils
{

  /**
   * Returns a new character array, after inserting characters into the given
   * character array.
   * 
   * @param in
   *          the character array to insert into
   * @param position
   *          the 0-based position for insertion
   * @param count
   *          the number of characters to insert
   * @param ch
   *          the character to insert
   */
  public static final char[] insertCharAt(char[] in, int position,
          int count,
          char ch)
  {
    char[] tmp = new char[in.length + count];
  
    if (position >= in.length)
    {
      System.arraycopy(in, 0, tmp, 0, in.length);
      position = in.length;
    }
    else
    {
      System.arraycopy(in, 0, tmp, 0, position);
    }
  
    int index = position;
    while (count > 0)
    {
      tmp[index++] = ch;
      count--;
    }
  
    if (position < in.length)
    {
      System.arraycopy(in, position, tmp, index,
              in.length - position);
    }
  
    return tmp;
  }

  /**
   * Delete
   * 
   * @param in
   * @param from
   * @param to
   * @return
   */
  public static final char[] deleteChars(char[] in, int from, int to)
  {
    if (from >= in.length)
    {
      return in;
    }

    char[] tmp;

    if (to >= in.length)
    {
      tmp = new char[from];
      System.arraycopy(in, 0, tmp, 0, from);
      to = in.length;
    }
    else
    {
      tmp = new char[in.length - to + from];
      System.arraycopy(in, 0, tmp, 0, from);
      System.arraycopy(in, to, tmp, from, in.length - to);
    }
    return tmp;
  }

  /**
   * Returns the last part of 'input' after the last occurrence of 'token'. For
   * example to extract only the filename from a full path or URL.
   * 
   * @param input
   * @param token
   *          a delimiter which must be in regular expression format
   * @return
   */
  public static String getLastToken(String input, String token)
  {
    if (input == null)
    {
      return null;
    }
    if (token == null)
    {
      return input;
    }
    String[] st = input.split(token);
    return st[st.length - 1];
  }
}