if( p->iCursor<0 ){
    p->iCursor = 0;
  }

But iCursor is an unsigned integer and will never go bellow 0, therefore this code does nothing. If iCursor is decremented past 0 it will go to a very high number.

I guess I'm being pedantic, but if you took the trouble to write the code I suppose you must have thought it important to guard against this.