indexing
	description: "A low-level string class to solve some garbage collector problems (object move). The end-user must not use this class. Use class STRING instead."
	status: "See notice at end of class."
	date: "$Date$"
	revision: "$Revision$"

class interface
	WEL_STRING

create 

	make (a_string: STRING)
			-- Make a C string from a_string.
		require
			a_string_not_void: a_string /= void
		ensure
			not_shared: not shared

	make_empty (a_length: INTEGER)
			-- Make an empty C string of a_length characters.
			-- C memory area is not initialized.
		require
			positive_length: a_length >= 0

	make_by_pointer (a_pointer: POINTER)
			-- Set item with a_pointer.
			-- Since item is shared, it does not need
			-- to be freed.
			-- Caution: a_pointer must be a pointer
			-- coming from Windows.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			item_set: item = a_pointer
			shared: shared

feature -- Access

	count: INTEGER
			-- String length
			-- Was declared in WEL_STRING as synonym of length.

	item: POINTER
			-- Generic Windows handle or structure pointer.
			-- Can be a HWND, HICON, RECT *, WNDCLASS *, etc...
			-- (from WEL_ANY)

	length: INTEGER
			-- String length
			-- Was declared in WEL_STRING as synonym of count.

	null_separated_strings: LINKED_LIST [STRING]
			-- Retrieve all string contained in item. Strings are
			-- NULL separared inside item.
		ensure
			result_not_void: Result /= void

	space_separated_strings: LINKED_LIST [STRING]
			-- Retrieve all string contained in item. Strings are
			-- space-separared inside item.
		ensure
			result_not_void: Result /= void

	string: STRING
			-- Eiffel string
		ensure
			result_not_void: Result /= void
	
feature -- Measurement

	capacity: INTEGER
			-- Size of initial string (Needed for set_string precondition).

	structure_size: INTEGER
			-- String length
		ensure -- from WEL_STRUCTURE
			positive_result: Result > 0
	
feature -- Status report

	exists: BOOLEAN
			-- Does the item exist?
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			Result = (item /= default_pointer)

	shared: BOOLEAN
			-- Is item shared by another object?
			-- If False (by default), item will
			-- be destroyed by destroy_item.
			-- If True, item will not be destroyed.
			-- (from WEL_ANY)
	
feature -- Status setting

	set_shared
			-- Set shared to True.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			shared: shared

	set_unshared
			-- Set shared to False.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			unshared: not shared
	
feature -- Element change

	set_item (an_item: POINTER)
			-- Set item with an_item
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			item_set: item = an_item

	set_null_character (offset: INTEGER)
			-- Set %U at offset position of Current.
			-- First position being  at 0 index.
		require
			valid_offset: offset >= 0 and offset < capacity

	set_size_in_string (n: INTEGER)
			-- Set two first bytes of string pointed by item to
			-- value represented by n in a two bytes representation.
		require
			valid_size: n > 0

	set_string (a_string: STRING)
			-- Set string with a_string.
		require
			a_string_not_void: a_string /= void
			valid_count: a_string.count < capacity
		ensure
			string_set: a_string.is_equal (string)
	
feature -- Removal

	dispose
			-- Destroy the inner structure of Current.
			--
			-- This function should be called by the GC when the
			-- object is collected or by the user if Current is
			-- no more usefull.
			-- (from WEL_ANY)
	
feature -- Conversion

	to_integer: INTEGER
			-- Converts item to an integer.
			-- (from WEL_ANY)
		ensure -- from WEL_ANY
			Result = cwel_pointer_to_integer (item)
	
feature -- Basic operations

	initialize
			-- Fill Current with zeros.
			-- (from WEL_STRUCTURE)
		require -- from WEL_STRUCTURE
			exists: exists

	initialize_with_character (a_character: CHARACTER)
			-- Fill current with a_character.
			-- (from WEL_STRUCTURE)
		require -- from WEL_STRUCTURE
			exists: exists

	memory_copy (source_pointer: POINTER; length: INTEGER)
			-- Copy length bytes from source_pointer to item.
			-- (from WEL_STRUCTURE)
		require -- from WEL_STRUCTURE
			length_small_enough: length <= structure_size
			length_large_enough: length > 0
			exists: exists
	
invariant

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class WEL_STRING