Name: bsT130419 Date: 10/12/2001


java version "1.3.1_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_01)
Java HotSpot(TM) Client VM (build 1.3.1_01, mixed mode)

The loop for String.equals is not very efficient. It can be
made 40% faster for strings longer than 4 characters by
unrolling it four times. Even though this incurs a slight
performance penalty for comparison of strings shorter than
4 characters, it seems worth it overall. Here is the new
code:

public boolean equals( Object anObject )
{
  if (anObject == this)
    return true;

  if (anObject instanceof String1)
  {
    String1 other = (String1) anObject;
    int n = count;
    if (n == other.count)
    {
      char[] v1 = value;
      char[] v2 = other.value;
      int i = offset;
      int j = other.offset;

      while (n >= 4)
      {
        if (v1[i] != v2[j] || v1[i+1] != v2[j+1] ||
            v1[i+2] != v2[j+2] || v1[i+3] != v2[j+3])
          return false;

        i += 4;
        j += 4;
        n -= 4;
      }

      while (n-- >= 1)
        if (v1[i++] != v2[j++])
          return false;

      return true;
    }
  }

  return false;
}
(Review ID: 133604)
======================================================================

No description of the performance test method or platform was given.

###@###.### 2001-10-12