nsIRandomAccessIterator Interface

 Create a new iterator pointing to the same position in the underlying container or sequence to which this iterator currently points.
 The returned iterator is suitable for use in a subsequent call to |isEqualTo()| against this iterator.

 @result a new iterator pointing at the same position in the same underlying container or sequence as this iterator

nsISupports clone()

 Retrieve (and |AddRef()|) the element this iterator currently points to.

 The result is undefined if this iterator currently points outside the
 useful range of the underlying container or sequence.

 @result a new reference to the element this iterator currently points to (if any)

nsISupports getElement()

 Retrieve (and |AddRef()|) an element at some offset from where this iterator currently points.
 The offset may be negative.  |getElementAt(0)| is equivalent to |getElement()|.

 The result is undefined if this iterator currently points outside the
 useful range of the underlying container or sequence.

 @param anOffset a |0|-based offset from the position to which this iterator currently points
 @result a new reference to the indicated element (if any)

nsISupports getElementAt(in PRInt32 anOffset)

 Test if |anotherIterator| points to the same position in the underlying container or sequence.

 The result is undefined if |anotherIterator| was not created by or for the same underlying container or sequence.

 @param anotherIterator another iterator to compare against, created by or for the same underlying container or sequence
 @result true if |anotherIterator| points to the same position in the underlying container or sequence

boolean isEqualTo(in nsISupports anotherIterator)

 Put |anElementToPut| into the underlying container or sequence at the position currently pointed to by this iterator.
 The iterator and the underlying container or sequence cooperate to |Release()|
 the replaced element, if any and if necessary, and to |AddRef()| the new element.

 The result is undefined if this iterator currently points outside the
 useful range of the underlying container or sequence.

 @param anElementToPut the element to place into the underlying container or sequence

void putElement(in nsISupports anElementToPut)

 Put |anElementToPut| into the underlying container or sequence at the position |anOffset| away from that currently pointed to by this iterator.
 The iterator and the underlying container or sequence cooperate to |Release()|
 the replaced element, if any and if necessary, and to |AddRef()| the new element.
 |putElementAt(0, obj)| is equivalent to |putElement(obj)|.

 The result is undefined if this iterator currently points outside the
 useful range of the underlying container or sequence.

 @param anOffset a |0|-based offset from the position to which this iterator currently points
 @param anElementToPut the element to place into the underlying container or sequence

void putElementAt(in PRInt32 anOffset, in nsISupports anElementToPut)

 Move this iterator to the previous position in the underlying container or sequence.

void stepBackward()

 Move this iterator backwards by |anOffset| positions in the underlying container or sequence.
 |anOffset| may be negative.  |stepBackwardBy(1)| is equivalent to |stepBackward()|.
 |stepBackwardBy(n)| is equivalent to |stepForwardBy(-n)|.  |stepBackwardBy(0)| is a no-op.

 @param anOffset a |0|-based offset from the position to which this iterator currently points

void stepBackwardBy(in PRInt32 anOffset)

 Advance this iterator to the next position in the underlying container or sequence.

void stepForward()

 Move this iterator by |anOffset| positions in the underlying container or sequence.
 |anOffset| may be negative.  |stepForwardBy(1)| is equivalent to |stepForward()|.
 |stepForwardBy(0)| is a no-op.

 @param anOffset a |0|-based offset from the position to which this iterator currently points

void stepForwardBy(in PRInt32 anOffset)