/src/wrappers/glib/library/data_types/iterator_on_g_list.e

 1indexing
 2	description: "."
 3	copyright: "(C) 2006 Paolo Redaelli "
 4	license: "LGPL v2 or later"
 5	date: "$Date:$"
 6	revision: "$Revision:$"
 7
 8class ITERATOR_ON_G_LIST [ITEM->WRAPPER]
 9inherit
10	ITERATOR [ITEM]
11	WRAPPER_HANDLER
12
13insert
14   GLIST_EXTERNALS
15   GLIST_STRUCT
16   GLOBAL_CACHE
17	
18creation make
19	
20feature {} -- Creation
21	make (a_list: G_LIST_TRAVERSABLE[ITEM]) is
22		require
23         valid_list: a_list /= Void
24		do
25			list := a_list
26		end
27	
28feature {} -- Implementation
29	list: G_LIST_TRAVERSABLE[ITEM]
30	current_element: POINTER
31
32feature -- Iterator's features
33	start is
34		do
35			current_element := list.handle
36		end
37	
38	is_off: BOOLEAN is
39		do
40			Result := (current_element.is_null)
41		end
42	
43	item: ITEM is
44		local
45         ptr: POINTER
46         l: WRAPPER
47		do
48			ptr := glist_struct_get_data (current_element)
49			if ptr.is_not_null then
50				l := wrappers.reference_at(ptr)
51				Result ?= l -- TODO: this tricks the compiler. Combining the line just above and this one seems to fail
52				if Result=Void 
53					then Result:=list.wrapper(ptr) 
54				end
55			end
56		end
57	
58	next is
59		do
60			current_element := glist_struct_get_next (current_element)
61		end
62
63feature -- Bi-directional iterator features.
64	is_at_first: BOOLEAN is
65			-- Is Current iterator at the beginning of the G_LIST?
66		do
67			Result := (current_element = list.handle)
68		end
69	
70	prev is
71		require past_start: not is_at_first
72		do
73			current_element := glist_struct_get_prev (current_element)
74		end
75
76	--feature dispose is do -- Note: disposing an interator is a
77	--no-operation.  end
78end