Automatic generation produced by ISE Eiffel
indexing description: "Trees implemented using a two way linked list representation" status: "See notice at end of class" names: two_way_tree, tree, two_way_list representation: recursive, linked access: cursor, membership contents: generic date: "$Date: 2001-11-16 20:32:23 +0000 (Fri, 16 Nov 2001) $" revision: "$Revision: 51435 $" class interface TWO_WAY_TREE [G] create make (v: like item) -- Create single node with item v. feature -- Initialization make (v: like item) -- Create single node with item v. feature -- Access child_cursor: CURSOR -- Current cursor position -- (from LINKED_LIST) first: like child_item -- Item at first position -- (from LINKED_LIST) require -- from CHAIN not_empty: not is_leaf first_child: like parent -- Leftmost child i_th (i: INTEGER): like child_item -- Item at i-th position -- Was declared in CHAIN as synonym of @. -- (from CHAIN) require -- from TABLE valid_key: valid_index (k) child_index: INTEGER -- Index of current position -- (from LINKED_LIST) ensure -- from TREE valid_index: Result >= 0 and Result <= arity + 1 index_of (v: like child_item; i: INTEGER): INTEGER -- Index of i-th occurrence of item identical to v. -- (Reference or object equality, -- based on object_comparison.) -- 0 if none. -- (from CHAIN) require -- from LINEAR positive_occurrences: i > 0 ensure -- from LINEAR non_negative_result: Result >= 0 child_item: G -- Current item -- (from LINKED_LIST) require -- from TRAVERSABLE not_off: not child_off require -- from ACTIVE readable: child_readable require -- from TREE readable: child_readable item: G -- Content of cell. -- (from CELL) last: like child_item -- Item at last position -- (from LINKED_LIST) require -- from CHAIN not_empty: not is_leaf last_child: like parent left_sibling: like Current -- Left neighbor -- (from BI_LINKABLE) sequential_occurrences (v: G): INTEGER -- Number of times v appears. -- (Reference or object equality, -- based on object_comparison.) -- (from LINEAR) ensure -- from BAG non_negative_occurrences: Result >= 0 parent: TWO_WAY_TREE [G] -- Parent node right_sibling: like Current -- Right neighbor -- (from LINKABLE) sublist: like Current -- Result produced by last split -- (from TWO_WAY_LIST) infix "@" (i: INTEGER): like child_item -- Item at i-th position -- Was declared in CHAIN as synonym of i_th. -- (from CHAIN) require -- from TABLE valid_key: valid_index (k) feature -- Measurement child_capacity: INTEGER -- Maximal number of children -- (from TREE) count: INTEGER -- Number of items -- (from TREE) arity: INTEGER -- Number of items -- (from LINKED_LIST) index_set: INTEGER_INTERVAL -- Range of acceptable indexes -- (from CHAIN) ensure -- from INDEXABLE not_void: Result /= void ensure then -- from CHAIN count_definition: Result.count = arity occurrences (v: like child_item): INTEGER -- Number of times v appears. -- (Reference or object equality, -- based on object_comparison.) -- (from CHAIN) ensure -- from BAG non_negative_occurrences: Result >= 0 occurrences (v: like child_item): INTEGER -- Number of times v appears. -- (Reference or object equality, -- based on object_comparison.) -- (from CHAIN) ensure -- from BAG non_negative_occurrences: Result >= 0 feature -- Comparison is_equal (other: like Current): BOOLEAN -- Does other contain the same elements? -- (Reference or object equality, -- based on object_comparison.) -- (from TREE) require -- from ANY other_not_void: other /= void ensure -- from ANY symmetric: Result implies other.is_equal (Current) consistent: standard_is_equal (other) implies Result ensure then -- from LIST indices_unchanged: child_index = old child_index and other.child_index = old other.child_index true_implies_same_size: Result implies arity = other.arity feature -- Status report child_after: BOOLEAN -- Is there no valid cursor position to the right of cursor? -- (from LINKED_LIST) child_before: BOOLEAN -- Is there no valid cursor position to the left of cursor? -- (from LINKED_LIST) changeable_comparison_criterion: BOOLEAN -- May object_comparison be changed? -- (Answer: yes by default.) -- (from CONTAINER) child_isfirst: BOOLEAN -- Is cursor under first child? -- (from TREE) ensure -- from CHAIN valid_position: Result implies not is_leaf ensure -- from TREE not_is_leaf: Result implies not is_leaf child_islast: BOOLEAN -- Is cursor under last child? -- (from TREE) ensure -- from CHAIN valid_position: Result implies not is_leaf ensure -- from TREE not_is_leaf: Result implies not is_leaf child_readable: BOOLEAN -- Is there a current child_item to be read? -- (from TREE) child_writable: BOOLEAN -- Is there a current child_item that may be modified? -- (from TREE) exhausted: BOOLEAN -- Has structure been completely explored? -- (from LINEAR) ensure -- from LINEAR exhausted_when_off: child_off implies Result Extendible: BOOLEAN is True -- May new items be added? -- (from DYNAMIC_TREE) Child_extendible: BOOLEAN is True -- May new items be added? (Answer: yes.) -- (from DYNAMIC_CHAIN) has (v: G): BOOLEAN -- Does subtree include v? -- (Reference or object equality, -- based on object_comparison.) -- (from TREE) ensure -- from CONTAINER not_found_in_empty: Result implies not is_leaf is_empty: BOOLEAN -- Is structure empty of items? -- (from TREE) is_inserted (v: G): BOOLEAN -- Has v been inserted at the end by the most recent put or -- extend? -- (from LINKED_LIST) is_leaf: BOOLEAN -- Are there no children? -- (from TREE) is_root: BOOLEAN -- Is there no parent? -- (from TREE) is_sibling (other: like parent): BOOLEAN -- Are current node and other siblings? -- (from TREE) require -- from TREE other_exists: other /= void ensure -- from TREE not_root: Result implies not is_root other_not_root: Result implies not other.is_root same_parent: Result = not is_root and other.parent = parent object_comparison: BOOLEAN -- Must search operations use equal rather than = -- for comparing references? (Default: no, use =.) -- (from CONTAINER) child_off: BOOLEAN -- Is there no current item? -- (from LINKED_LIST) prunable: BOOLEAN -- May items be removed? (Answer: yes.) -- (from DYNAMIC_CHAIN) Readable: BOOLEAN is True -- (from TREE) readable_child: BOOLEAN -- Is there a current child to be read? -- (from TREE) valid_cursor (p: CURSOR): BOOLEAN -- Can the cursor be moved to position p? -- (from LINKED_LIST) valid_cursor_index (i: INTEGER): BOOLEAN -- Is i correctly bounded for cursor movement? -- (from TREE) ensure -- from CHAIN valid_cursor_index_definition: Result = ((i >= 0) and (i <= arity + 1)) ensure -- from TREE valid_cursor_index_definition: Result = (i >= 0) and (i <= child_capacity + 1) valid_index (i: INTEGER): BOOLEAN -- Is i within allowable bounds? -- (from CHAIN) ensure then -- from INDEXABLE only_if_in_index_set: Result implies ((i >= index_set.lower) and (i <= index_set.upper)) ensure then -- from CHAIN valid_index_definition: Result = ((i >= 1) and (i <= arity)) Writable: BOOLEAN is True -- Is there a current item that may be modified? -- (from TREE) writable_child: BOOLEAN -- Is there a current child that may be modified? -- (from TREE) feature -- Status setting compare_objects -- Ensure that future search operations will use equal -- rather than = for comparing references. -- (from CONTAINER) require -- from CONTAINER changeable_comparison_criterion ensure -- from CONTAINER object_comparison compare_references -- Ensure that future search operations will use = -- rather than equal for comparing references. -- (from CONTAINER) require -- from CONTAINER changeable_comparison_criterion ensure -- from CONTAINER reference_comparison: not object_comparison feature -- Cursor movement child_back -- Move cursor to previous position, if any. -- (from TWO_WAY_LIST) require -- from TREE True require -- from BILINEAR not_before: not child_before child_finish -- Move cursor to last position. -- (Go before if empty) -- (from TWO_WAY_LIST) ensure then -- from CHAIN at_last: not is_leaf implies child_islast ensure then -- from LINKED_LIST empty_convention: is_leaf implies child_before ensure then -- from TREE is_last_child: not is_leaf implies child_islast ensure then -- from TWO_WAY_LIST not_after: not child_after child_forth -- Move cursor to next position, if any. -- (from TWO_WAY_LIST) require -- from TREE True require -- from LINEAR not_after: not child_after ensure then -- from LIST moved_forth: child_index = old child_index + 1 child_go_i_th (i: INTEGER) -- Move cursor to i-th position. -- (from LINKED_LIST) require -- from CHAIN valid_cursor_index: valid_cursor_index (i) require else -- from TREE valid_cursor_index: valid_cursor_index (i) ensure -- from CHAIN position_expected: child_index = i ensure then -- from TREE position: child_index = i child_go_to (p: CURSOR) -- Move cursor to position p. -- (from LINKED_LIST) require -- from TREE True require -- from CURSOR_STRUCTURE cursor_position_valid: valid_cursor (p) move (i: INTEGER) -- Move cursor i positions. The cursor -- may end up off if the offset is to big. -- (from TWO_WAY_LIST) ensure -- from CHAIN too_far_right: (old child_index + i > arity) implies exhausted too_far_left: (old child_index + i < 1) implies exhausted expected_index: (not exhausted) implies (child_index = old child_index + i) ensure then -- from LINKED_LIST moved_if_inbounds: ((old child_index + i) >= 0 and (old child_index + i) <= (arity + 1)) implies child_index = (old child_index + i) before_set: (old child_index + i) <= 0 implies child_before after_set: (old child_index + i) >= (arity + 1) implies child_after search_child (v: like child_item) -- Move to first position (at or after current -- position) where item and v are equal. -- If structure does not include v ensure that -- exhausted will be true. -- (Reference or object equality, -- based on object_comparison.) -- (from BILINEAR) ensure -- from LINEAR object_found: (not exhausted and object_comparison) implies equal (v, child_item) item_found: (not exhausted and not object_comparison) implies v = child_item child_start -- Move cursor to first position. -- (from LINKED_LIST) ensure then -- from CHAIN at_first: not is_leaf implies child_isfirst ensure then -- from TREE is_first_child: not is_leaf implies child_isfirst ensure then -- from LINKED_LIST empty_convention: is_leaf implies child_after feature -- Element change append (s: SEQUENCE [G]) -- Append a copy of s. -- (from SEQUENCE) require -- from SEQUENCE argument_not_void: s /= void ensure -- from SEQUENCE new_count: arity >= old arity extend (v: like item) -- Add v as new child. -- (from DYNAMIC_TREE) child_extend (v: like child_item) -- Add v to end. -- Do not move cursor. -- (from TWO_WAY_LIST) require -- from DYNAMIC_TREE True require -- from COLLECTION extendible: child_extendible ensure -- from COLLECTION item_inserted: is_inserted (v) ensure then -- from BAG one_more_occurrence: occurrences (v) = old (occurrences (v)) + 1 fill (other: TREE [G]) -- Fill with as many items of other as possible. -- The representations of other and current node -- need not be the same. -- (from TREE) force (v: like child_item) -- Add v to end. -- (from SEQUENCE) require -- from SEQUENCE extendible: child_extendible ensure then -- from SEQUENCE new_count: arity = old arity + 1 item_inserted: has (v) twl_merge_left (other: like Current) -- Merge other into current structure before cursor -- position. Do not move cursor. Empty other. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN extendible: child_extendible not_before: not child_before other_exists: other /= void ensure -- from DYNAMIC_CHAIN new_count: arity = old arity + old other.arity new_index: child_index = old child_index + old other.arity other_is_empty: other.is_leaf ensure then -- from DYNAMIC_LIST other_empty: other.is_leaf twl_merge_right (other: like Current) -- Merge other into current structure after cursor -- position. Do not move cursor. Empty other. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN extendible: child_extendible not_after: not child_after other_exists: other /= void ensure -- from DYNAMIC_CHAIN new_count: arity = old arity + old other.arity same_index: child_index = old child_index other_is_empty: other.is_leaf ensure then -- from DYNAMIC_LIST other_empty: other.is_leaf merge_tree_after (other: like first_child) -- Merge children of other into current structure -- after cursor position. Do not move cursor. -- Make other a leaf. require -- from DYNAMIC_TREE not_child_off: not child_off other_exists: (other /= void) ensure -- from DYNAMIC_TREE other_is_leaf: other.is_leaf merge_tree_before (other: like first_child) -- Merge children of other into current structure -- after cursor position. Do not move cursor. -- Make other a leaf. require -- from DYNAMIC_TREE not_child_off: not child_off other_exists: (other /= void) ensure -- from DYNAMIC_TREE other_is_leaf: other.is_leaf prune (n: like first_child) require -- from TREE is_child: n.parent = Current ensure -- from TREE n_is_root: n.is_root put (v: like item) -- Make v the cell's item. -- Was declared in CELL as synonym of replace. -- (from CELL) require -- from TREE is_writable: writable ensure -- from TREE item_inserted: item = v ensure -- from CELL item_inserted: item = v child_put (v: like child_item) -- Replace current item by v. -- (Synonym for replace) -- (from CHAIN) require -- from COLLECTION extendible: child_extendible require -- from TREE child_writable: child_writable ensure -- from COLLECTION item_inserted: is_inserted (v) ensure -- from TREE item_inserted: child_item = v ensure then -- from CHAIN same_count: arity = old arity put_child (n: like parent) -- Add n to the list of children. -- Do not move child cursor. require else -- from DYNAMIC_TREE non_void_argument: n /= void put_child_left (n: like parent) -- Add n to the left of cursor position. -- Do not move cursor. require -- from DYNAMIC_TREE not_child_before: not child_before non_void_argument: n /= void put_child_right (n: like parent) -- Add n to the right of cursor position. -- Do not move cursor. require -- from DYNAMIC_TREE not_child_after: not child_after non_void_argument: n /= void put_front (v: like child_item) -- Add v to beginning. -- Do not move cursor. -- (from TWO_WAY_LIST) ensure -- from DYNAMIC_CHAIN new_count: arity = old arity + 1 item_inserted: first = v put_i_th (v: like child_item; i: INTEGER) -- Put v at i-th position. -- (from CHAIN) require -- from TABLE valid_key: valid_index (k) ensure then -- from INDEXABLE insertion_done: i_th (k) = v child_put_left (v: like child_item) -- Add v to the left of cursor position. -- Do not move cursor. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN extendible: child_extendible not_before: not child_before require -- from DYNAMIC_TREE not_child_before: not child_before ensure -- from DYNAMIC_CHAIN new_count: arity = old arity + 1 new_index: child_index = old child_index + 1 ensure then -- from LINKED_LIST previous_exists: previous /= void item_inserted: previous.item = v child_put_right (v: like child_item) -- Add v to the right of cursor position. -- Do not move cursor. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN extendible: child_extendible not_after: not child_after require -- from DYNAMIC_TREE not_child_after: not child_after ensure -- from DYNAMIC_CHAIN new_count: arity = old arity + 1 same_index: child_index = old child_index ensure then -- from LINKED_LIST next_exists: next /= void item_inserted: not old child_before implies next.item = v item_inserted_before: old child_before implies child.item = v replace (v: like item) -- Make v the cell's item. -- Was declared in CELL as synonym of put. -- (from CELL) require -- from TREE is_writable: writable ensure -- from TREE item_inserted: item = v ensure -- from CELL item_inserted: item = v child_replace (v: like child_item) -- Replace current item by v. -- (from LINKED_LIST) require -- from ACTIVE writable: child_writable require -- from TREE child_writable: child_writable ensure -- from ACTIVE item_replaced: child_item = v ensure -- from TREE item_inserted: child_item = v replace_child (n: like parent) -- Replace current child by n. require -- from TREE writable_child: writable_child was_root: n.is_root ensure -- from TREE child_replaced: child = n sprout -- Make current node a root. -- (from TREE) feature -- Removal twl_prune (v: like child_item) -- Remove first occurrence of v, if any, -- after cursor position. -- If found, move cursor to right neighbor; -- if not, make structure exhausted. -- (from DYNAMIC_CHAIN) require -- from COLLECTION prunable: prunable prune_all (v: like child_item) -- Remove all occurrences of v. -- (Reference or object equality, -- based on object_comparison.) -- Leave structure exhausted. -- (from DYNAMIC_CHAIN) require -- from COLLECTION prunable ensure -- from COLLECTION no_more_occurrences: not has (v) ensure then -- from DYNAMIC_CHAIN is_exhausted: exhausted remove_child -- Remove current item. -- Move cursor to right neighbor -- (or after if no right neighbor). -- (from TWO_WAY_LIST) require -- from ACTIVE prunable: prunable writable: child_writable require -- from DYNAMIC_TREE child_not_off: not child_off ensure then -- from DYNAMIC_LIST after_when_empty: is_leaf implies child_after ensure -- from DYNAMIC_TREE new_arity: arity = old arity - 1 new_child_index: child_index = old child_index remove_left_child -- Remove item to the left of cursor position. -- Do not move cursor. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN left_exists: child_index > 1 require else -- from DYNAMIC_LIST not_before: not child_before require -- from DYNAMIC_TREE is_not_first: not child_isfirst ensure -- from DYNAMIC_CHAIN new_count: arity = old arity - 1 new_index: child_index = old child_index - 1 ensure -- from DYNAMIC_TREE new_arity: arity = old arity - 1 new_child_index: child_index = old child_index - 1 remove_right_child -- Remove item to the right of cursor position. -- Do not move cursor. -- (from TWO_WAY_LIST) require -- from DYNAMIC_CHAIN right_exists: child_index < arity require -- from DYNAMIC_TREE is_not_last: not child_islast ensure -- from DYNAMIC_CHAIN new_count: arity = old arity - 1 same_index: child_index = old child_index ensure -- from DYNAMIC_TREE new_arity: arity = old arity - 1 new_child_index: child_index = old child_index remove_sublist -- (from TWO_WAY_LIST) split (n: INTEGER) -- Remove from current list -- min (n, count - index - 1) items -- starting at cursor position. -- Move cursor right one position. -- Make extracted sublist accessible -- through attribute sublist. -- (from TWO_WAY_LIST) require -- from TWO_WAY_LIST not_off: not child_off valid_sublist: n >= 0 wipe_out -- Remove all items. -- (from TWO_WAY_LIST) require -- from DYNAMIC_TREE True require -- from COLLECTION prunable ensure -- from COLLECTION wiped_out: is_leaf ensure then -- from DYNAMIC_LIST is_before: child_before feature -- Transformation swap (i: INTEGER) -- Exchange item at i-th position with item -- at cursor position. -- (from CHAIN) require -- from CHAIN not_off: not child_off valid_index: valid_index (i) ensure -- from CHAIN swapped_to_item: child_item = old i_th (i) swapped_from_item: i_th (i) = old child_item feature -- Conversion binary_representation: BINARY_TREE [G] -- Convert to binary tree representation: -- first child becomes left child, -- right sibling becomes right child. -- (from TREE) ensure -- from TREE result_is_root: Result.is_root result_has_no_right_child: not Result.has_right fill_from_binary (b: BINARY_TREE [G]) -- Fill from a binary tree representation. -- Left child becomes first child. -- Right child becomes right sibling. -- Any right child of b is ignored. -- (from DYNAMIC_TREE) linear_representation: LINEAR [G] -- Representation as a linear structure -- (from TREE) feature -- Duplication copy (other: like Current) -- Copy contents from other. require -- from ANY other_not_void: other /= void type_identity: same_type (other) ensure -- from ANY is_equal: is_equal (other) duplicate (n: INTEGER): like Current -- Copy of sub-tree beginning at cursor position and -- having min (n, arity - child_index + 1) -- children -- (from DYNAMIC_TREE) require -- from TREE not_child_off: not child_off valid_sublist: n >= 0 feature -- Implementation child: like first_child -- Element at cursor position -- (from LINKED_LIST) feature -- Iteration do_all (action: PROCEDURE [ANY, TUPLE [G]]) -- Apply action to every item. -- Semantics not guaranteed if action changes the structure; -- in such a case, apply iterator to clone of structure instead. -- (from LINEAR) require -- from TRAVERSABLE action_exists: action /= void do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN]) -- Apply action to every item that satisfies test. -- Semantics not guaranteed if action or test changes the structure; -- in such a case, apply iterator to clone of structure instead. -- (from LINEAR) require -- from TRAVERSABLE action_exists: action /= void test_exits: test /= void for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN -- Is test true for all items? -- (from LINEAR) require -- from TRAVERSABLE test_exits: test /= void there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN -- Is test true for at least one item? -- (from LINEAR) require -- from TRAVERSABLE test_exits: test /= void invariant off_constraint: (child = void) implies child_off -- from ANY reflexive_equality: standard_is_equal (Current) reflexive_conformance: conforms_to (Current) -- from DYNAMIC_TREE extendible_definition: extendible child_after_definition: child_after = (child_index = arity + 1) -- from TREE leaf_definition: is_leaf = (arity = 0) child_off_definition: child_off = child_before or child_after child_before_definition: child_before = (child_index = 0) child_isfirst_definition: child_isfirst = (not is_leaf and child_index = 1) child_islast_definition: child_islast = (not is_leaf and child_index = child_capacity) child_after_definition: child_after = (child_index >= child_capacity + 1) child_consistency: child_readable implies child.parent = Current -- from BI_LINKABLE right_symmetry: (right_sibling /= void) implies (right_sibling.left_sibling = Current) left_symmetry: (left_sibling /= void) implies (left_sibling.right_sibling = Current) -- from TWO_WAY_LIST non_empty_list_has_two_endpoints: not is_leaf implies (first_child /= void and last_child /= void) first_element_constraint: first_child /= void implies first_child.left_sibling = void last_element_constraint: last_child /= void implies last_child.right_sibling = void -- from LINKED_LIST prunable: prunable empty_constraint: is_leaf implies ((first_child = void) and (child = void)) not_void_unless_empty: (child = void) implies is_leaf before_constraint: child_before implies (child = first_child) after_constraint: child_after implies (child = last_child) -- from LIST before_definition: child_before = (child_index = 0) after_definition: child_after = (child_index = arity + 1) -- from CHAIN non_negative_index: child_index >= 0 index_small_enough: child_index <= arity + 1 off_definition: child_off = ((child_index = 0) or (child_index = arity + 1)) isfirst_definition: child_isfirst = ((not is_leaf) and (child_index = 1)) islast_definition: child_islast = ((not is_leaf) and (child_index = arity)) item_corresponds_to_index: (not child_off) implies (child_item = i_th (child_index)) index_set_has_same_count: index_set.count = arity -- from ACTIVE writable_constraint: child_writable implies child_readable empty_constraint: is_leaf implies (not child_readable) and (not child_writable) -- from INDEXABLE index_set_not_void: index_set /= void -- from BILINEAR not_both: not (child_after and child_before) before_constraint: child_before implies child_off -- from LINEAR after_constraint: child_after implies child_off -- from TRAVERSABLE empty_constraint: is_leaf implies child_off -- from FINITE empty_definition: is_leaf = (arity = 0) non_negative_count: arity >= 0 -- from DYNAMIC_CHAIN extendible: child_extendible indexing library: "[ EiffelBase: Library of reusable components for Eiffel. ]" status: "[ Copyright 1986-2001 Interactive Software Engineering (ISE). For ISE customers the original versions are an ISE product covered by the ISE Eiffel license and support agreements. ]" license: "[ EiffelBase may now be used by anyone as FREE SOFTWARE to develop any product, public-domain or commercial, without payment to ISE, under the terms of the ISE Free Eiffel Library License (IFELL) at http://eiffel.com/products/base/license.html. ]" source: "[ Interactive Software Engineering Inc. ISE Building 360 Storke Road, Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Electronic mail <info@eiffel.com> Customer support http://support.eiffel.com ]" info: "[ For latest info see award-winning pages: http://eiffel.com ]" end -- class TWO_WAY_TREE -- Generated by ISE Eiffel --
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