+private class FlatStringReverseIterator
+ super IndexedIterator[Char]
+
+ var target: String
+
+ var target_items: NativeString
+
+ var curr_pos: Int
+
+ init with_pos(tgt: String, pos: Int)
+ do
+ target = tgt
+ target_items = tgt.items
+ curr_pos = pos + tgt.index_from
+ end
+
+ redef fun is_ok do return curr_pos >= 0
+
+ redef fun item do return target_items[curr_pos]
+
+ redef fun next do curr_pos -= 1
+
+ redef fun index do return curr_pos - target.index_from
+
+end
+
+private class FlatStringIterator
+ super IndexedIterator[Char]
+
+ var target: String
+
+ var target_items: NativeString
+
+ var curr_pos: Int
+
+ init with_pos(tgt: String, pos: Int)
+ do
+ target = tgt
+ target_items = tgt.items
+ curr_pos = pos + target.index_from
+ end
+
+ redef fun is_ok do return curr_pos <= target.index_to
+
+ redef fun item do return target_items[curr_pos]
+
+ redef fun next do curr_pos += 1
+
+ redef fun index do return curr_pos - target.index_from
+
+end
+
+private class FlatStringCharView
+ super StringCharView
+
+ redef type SELFTYPE: String
+
+ redef fun [](index)
+ do
+ # Check that the index (+ index_from) is not larger than indexTo
+ # In other terms, if the index is valid
+ assert index >= 0
+ assert (index + target.index_from) <= target.index_to
+ return target.items[index + target.index_from]
+ end
+
+ redef fun iterator_from(start) do return new FlatStringIterator.with_pos(target, start)
+
+ redef fun reverse_iterator_from(start) do return new FlatStringReverseIterator.with_pos(target, start)
+
+end
+
+abstract class Buffer
+ super Text
+
+ redef type SELFVIEW: BufferCharView
+ redef type SELFTYPE: Buffer
+
+ # Modifies the char contained at pos `index`
+ #
+ # DEPRECATED : Use self.chars.[]= instead
+ fun []=(index: Int, item: Char) is abstract
+
+ # Adds a char `c` at the end of self
+ #
+ # DEPRECATED : Use self.chars.add instead
+ fun add(c: Char) is abstract
+
+ # Clears the buffer
+ fun clear is abstract
+
+ # Enlarges the subsequent array containing the chars of self
+ fun enlarge(cap: Int) is abstract
+
+ # Adds the content of string `s` at the end of self
+ fun append(s: String) is abstract
+
+ redef fun chars: BufferCharView is abstract
+end
+