question: public int indexOf ( java . lang . String string ) { int start = 0 ; int subCount = string . count ; int _count = count ; if ( subCount > 0 ) { if ( subCount > _count ) { return - 1 ; } char [ ] target = string . value ; int subOffset = string . offset ; char firstChar = target [ subOffset ] ; int end = subOffset + subCount ; while ( true ) { int i = indexOf ( firstChar , start ) ; if ( i == - 1 || subCount + i > _count ) { return - 1 ; } int o1 = offset + i , o2 = subOffset ; char [ ] _value = value ; while ( ++ o2 < end && _value [ ++ o1 ] == target [ o2 ] ) { } if ( o2 == end ) { return i ; } start = i + 1 ; } } return start < _count ? start : _count ; }
target:  Returns the index within this string of the first occurrence of the specified substring. The integer returned is the smallest value such that: this.startsWith(str, ) is true.