Re: String.indexOf

[John Keiser]

On 08 Aug 2001 14:15:14 -0400, Patrick Doyle wrote:
> 
> I have made some modificatinos to String.indexOf and String.lastIndexOf so
> they better handle empty strings.  (Does Mauve test such cases?)
> 
> I don't have a great deal of confidence in the correctness of these
> changes, but as far as I can tell, they do bring the code closer to the
> wording of the String spec by fixing a few off-by-one errors.  Does
> someone else want to put their brain on this to see if it makes sense?  
> (Consider empty needle and haystack strings.)
> 
> Here's the patch.  It may not be 100% kosher because I have trimmed out
> some other modifications I made (which you don't want), but the changes
> are simple enough that they could be applied by hand if necessary:
> 
> 
> +++ String.java Wed Aug  8 14:04:28 2001
> @@ -688,7 +689,7 @@
>     */
>    public int indexOf(String str, int fromIndex) throws
> NullPointerException {
>      if (fromIndex < 0) fromIndex = 0;
> -    for (int i = fromIndex; i < count; i++)
> +    for (int i = fromIndex; i <= count; i++)
>        if (regionMatches(i, str, 0, str.count))
>         return i;
>      return -1;
> @@ -735,7 +736,7 @@
>     * @exception NullPointerException if `str' is null
>     */
>    public int lastIndexOf(String str) throws NullPointerException {
> -    return lastIndexOf(str, count-1);
> +    return lastIndexOf(str, count);
>    }
>  

I assume the sole purpose of this change is to make it so that a person
can call lastIndexOf("") and have it return count?

I can't think of any other effect the code could possibly have.

--John