note description: "Dynamically modifiable circular chains" library: "Free implementation of ELKS library" legal: "See notice at end of class." status: "See notice at end of class." names: dynamic_circular, ring, sequence access: index, cursor, membership contents: generic date: "$Date: 2018-11-13 12:58:34 +0000 (Tue, 13 Nov 2018) $" revision: "$Revision: 102449 $" deferred class interface DYNAMIC_CIRCULAR [G] feature -- Access at alias "@" (i: INTEGER_32): like item assign put_i_th -- Item at i-th position -- Was declared in CHAIN as synonym of i_th. -- (from CHAIN) require -- from TABLE valid_key: valid_index (i) cursor: CURSOR -- Current cursor position -- (from CURSOR_STRUCTURE) ensure -- from CURSOR_STRUCTURE cursor_not_void: Result /= Void first: G -- Item at position currently defined as first -- (from CIRCULAR) require -- from CHAIN not_empty: not is_empty generating_type: TYPE [detachable DYNAMIC_CIRCULAR [G]] -- Type of current object -- (type of which it is a direct instance) -- (from ANY) ensure -- from ANY generating_type_not_void: Result /= Void generator: STRING_8 -- Name of current object's generating class -- (base class of the type of which it is a direct instance) -- (from ANY) ensure -- from ANY generator_not_void: Result /= Void generator_not_empty: not Result.is_empty has (v: like item): BOOLEAN -- Does chain include v? -- (Reference or object equality, -- based on object_comparison.) -- (from CHAIN) sequential_has (v: like item): BOOLEAN -- Does structure include an occurrence of v? -- (Reference or object equality, -- based on object_comparison.) -- (from LINEAR) require -- from CONTAINER True ensure -- from CONTAINER not_found_in_empty: Result implies not is_empty i_th alias "[]" (i: INTEGER_32): like item assign put_i_th -- Item at i-th position -- Was declared in CHAIN as synonym of at. -- (from CHAIN) require -- from TABLE valid_key: valid_index (i) require -- from READABLE_INDEXABLE valid_index: valid_index (i) index: INTEGER_32 -- Current cursor index, with respect to position -- currently defined as first -- (from CIRCULAR) require -- from LINEAR True index_of (v: like item; i: INTEGER_32): INTEGER_32 -- Index of i-th occurrence of item identical to v. -- (Reference or object equality, -- based on object_comparison.) -- 0 if none. -- (from CHAIN) sequential_index_of (v: like item; i: INTEGER_32): INTEGER_32 -- Index of i-th occurrence of v. -- 0 if none. -- (Reference or object equality, -- based on object_comparison.) -- (from LINEAR) require -- from LINEAR positive_occurrences: i > 0 ensure -- from LINEAR non_negative_result: Result >= 0 item: G -- Current item -- (from ACTIVE) require -- from ACTIVE readable: readable require -- from TRAVERSABLE not_off: not off item_for_iteration: G -- Item at current position -- (from LINEAR) require -- from LINEAR not_off: not off last: like first -- Item at position currently defined as last -- (from CIRCULAR) require -- from CHAIN not_empty: not is_empty new_cursor: INDEXABLE_ITERATION_CURSOR [G] -- Fresh cursor associated with current structure -- (from READABLE_INDEXABLE) require -- from ITERABLE True ensure -- from ITERABLE result_attached: Result /= Void sequential_occurrences (v: like item): INTEGER_32 -- Number of times v appears. -- (Reference or object equality, -- based on object_comparison.) -- (from LINEAR) require -- from BAG True ensure -- from BAG non_negative_occurrences: Result >= 0 feature -- Measurement count: INTEGER_32 -- Number of items -- (from FINITE) require -- from READABLE_INDEXABLE True ensure -- from FINITE count_non_negative: Result >= 0 Lower: INTEGER_32 = 1 -- Minimum index. -- (from CHAIN) occurrences (v: like item): INTEGER_32 -- Number of times v appears. -- (Reference or object equality, -- based on object_comparison.) -- (from CHAIN) feature -- Comparison frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void -- or attached to isomorphic object structures? -- (from ANY) ensure -- from ANY instance_free: class shallow_implies_deep: standard_equal (a, b) implies Result both_or_none_void: (a = Void) implies (Result = (b = Void)) same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b)) symmetric: Result implies deep_equal (b, a) frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void or attached -- to objects considered equal? -- (from ANY) ensure -- from ANY instance_free: class definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b)) frozen is_deep_equal alias "≡≡≡" (other: DYNAMIC_CIRCULAR [G]): BOOLEAN -- Are Current and other attached to isomorphic object structures? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY shallow_implies_deep: standard_is_equal (other) implies Result same_type: Result implies same_type (other) symmetric: Result implies other.is_deep_equal (Current) is_equal (other: DYNAMIC_CIRCULAR [G]): BOOLEAN -- Is other attached to an object considered -- equal to current object? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY symmetric: Result implies other ~ Current consistent: standard_is_equal (other) implies Result frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN -- Are a and b either both void or attached to -- field-by-field identical objects of the same type? -- Always uses default object comparison criterion. -- (from ANY) ensure -- from ANY instance_free: class definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b)) frozen standard_is_equal alias "≜" (other: DYNAMIC_CIRCULAR [G]): BOOLEAN -- Is other attached to an object of the same type -- as current object, and field-by-field identical to it? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY same_type: Result implies same_type (other) symmetric: Result implies other.standard_is_equal (Current) feature -- Status report after: BOOLEAN -- Is there no valid cursor position to the right of cursor? -- (from CIRCULAR) require -- from LINEAR True ensure then -- from CIRCULAR empty_and_std_after: Result = (is_empty and standard_after) before: BOOLEAN -- Is there no valid cursor position to the right of cursor? -- (from CIRCULAR) require -- from BILINEAR True ensure then -- from CIRCULAR empty_and_std_before: Result = (is_empty and standard_before) changeable_comparison_criterion: BOOLEAN -- May object_comparison be changed? -- (Answer: yes by default.) -- (from CONTAINER) conforms_to (other: ANY): BOOLEAN -- Does type of current object conform to type -- of other (as per Eiffel: The Language, chapter 13)? -- (from ANY) require -- from ANY other_not_void: other /= Void exhausted: BOOLEAN -- Has structure been completely explored? -- (from CIRCULAR) require -- from LINEAR True ensure -- from LINEAR exhausted_when_off: off implies Result extendible: BOOLEAN -- May new items be added? (Answer: yes.) -- (from DYNAMIC_CHAIN) require -- from COLLECTION True full: BOOLEAN -- Is structure filled to capacity? -- (from BOX) is_empty: BOOLEAN -- Is structure empty? -- (from FINITE) require -- from CONTAINER True is_inserted (v: G): BOOLEAN -- Has v been inserted by the most recent insertion? -- (By default, the value returned is equivalent to calling -- has (v). However, descendants might be able to provide more -- efficient implementations.) -- (from COLLECTION) isfirst: BOOLEAN -- Is cursor at first position? -- (from CHAIN) ensure -- from CHAIN valid_position: Result implies not is_empty islast: BOOLEAN -- Is cursor at last position? -- (from CHAIN) ensure -- from CHAIN valid_position: Result implies not is_empty object_comparison: BOOLEAN -- Must search operations use equal rather than = -- for comparing references? (Default: no, use =.) -- (from CONTAINER) off: BOOLEAN -- Is there no current item? -- (from CIRCULAR) require -- from TRAVERSABLE True ensure then -- from CIRCULAR only_when_empty: Result = is_empty prunable: BOOLEAN -- May items be removed? (Answer: yes.) -- (from DYNAMIC_TABLE) require -- from COLLECTION True readable: BOOLEAN -- Is there a current item that may be read? -- (from SEQUENCE) require -- from ACTIVE True replaceable: BOOLEAN -- Can current item be replaced? -- (from ACTIVE) same_type (other: ANY): BOOLEAN -- Is type of current object identical to type of other? -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY definition: Result = (conforms_to (other) and other.conforms_to (Current)) valid_cursor (p: CURSOR): BOOLEAN -- Can the cursor be moved to position p? -- (from CURSOR_STRUCTURE) valid_cursor_index (i: INTEGER_32): BOOLEAN -- Is i a possible cursor position? -- (from CIRCULAR) require -- from CHAIN True ensure -- from CHAIN valid_cursor_index_definition: Result = ((i >= 0) and (i <= count + 1)) ensure then -- from CIRCULAR valid_cursor_index_definition: Result = ((i >= 0) and (i <= count)) valid_index (i: INTEGER_32): BOOLEAN -- Is i within allowable bounds? -- (from CHAIN) require -- from READABLE_INDEXABLE True require -- from TABLE True ensure -- from READABLE_INDEXABLE only_if_in_index_set: Result implies (Lower <= i and i <= count) ensure then -- from CHAIN valid_index_definition: Result = ((i >= 1) and (i <= count)) writable: BOOLEAN -- Is there a current item that may be modified? -- (from SEQUENCE) require -- from ACTIVE True 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: 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: changeable_comparison_criterion ensure -- from CONTAINER reference_comparison: not object_comparison feature -- Cursor movement back -- Move cursor to previous item, cyclically. -- (from CIRCULAR) require -- from BILINEAR not_before: not before finish -- Move cursor to last position. -- (No effect if empty) -- (from CHAIN) require -- from LINEAR True ensure then -- from CHAIN at_last: not is_empty implies islast forth -- Move cursor to next item, cyclically. -- (from CIRCULAR) require -- from LINEAR not_after: not after ensure then -- from CIRCULAR moved_forth_at_end: (old index = count) implies (index = 1) go_i_th (i: INTEGER_32) -- Move cursor to i-th position from current start, cyclically. -- (from CIRCULAR) require -- from CHAIN valid_cursor_index: valid_cursor_index (i) require else -- from CIRCULAR index_big_enough: i >= 1 not_empty: not is_empty ensure -- from CHAIN position_expected: index = i go_to (p: CURSOR) -- Move cursor to position p. -- (from CURSOR_STRUCTURE) require -- from CURSOR_STRUCTURE cursor_position_valid: valid_cursor (p) move (i: INTEGER_32) -- Move cursor to i-th item from current position, -- cyclically. -- (from CIRCULAR) require -- from CHAIN True ensure -- from CHAIN too_far_right: (old index + i > count) implies exhausted too_far_left: (old index + i < 1) implies exhausted expected_index: (not exhausted) implies (index = old index + i) search (v: like 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) require -- from LINEAR True ensure -- from LINEAR object_found: (not exhausted and object_comparison) implies v ~ item item_found: (not exhausted and not object_comparison) implies v = item set_start -- Define current position as the first. -- (from CIRCULAR) require -- from CIRCULAR not_empty: not is_empty start -- Move cursor to first position. -- (No effect if empty) -- (from CHAIN) require -- from TRAVERSABLE True ensure then -- from CHAIN at_first: not is_empty implies isfirst feature -- Element change append (s: SEQUENCE [G]) -- Append a copy of s. -- (from CHAIN) require -- from SEQUENCE argument_not_void: s /= Void ensure -- from SEQUENCE new_count: count >= old count extend (v: G) -- Add a new occurrence of v. -- (from BAG) require -- from COLLECTION extendible: extendible ensure -- from COLLECTION item_inserted: is_inserted (v) fill (other: CONTAINER [G]) -- Fill with as many items of other as possible. -- The representations of other and current structure -- need not be the same. -- (from CHAIN) require -- from COLLECTION other_not_void: other /= Void extendible: extendible force (v: like item) -- Add v to end. -- (from SEQUENCE) require -- from SEQUENCE extendible: extendible ensure then -- from SEQUENCE new_count: count = old count + 1 item_inserted: has (v) merge_left (other: DYNAMIC_CIRCULAR [G]) -- Merge other into current structure before cursor -- position. Do not move cursor. Empty other. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN extendible: extendible not_before: not before other_exists: other /= Void not_current: other /= Current ensure -- from DYNAMIC_CHAIN new_count: count = old count + old other.count new_index: index = old index + old other.count other_is_empty: other.is_empty merge_right (other: DYNAMIC_CIRCULAR [G]) -- Merge other into current structure after cursor -- position. Do not move cursor. Empty other. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN extendible: extendible not_after: not after other_exists: other /= Void not_current: other /= Current ensure -- from DYNAMIC_CHAIN new_count: count = old count + old other.count same_index: index = old index other_is_empty: other.is_empty put (v: like item) -- Replace current item by v. -- (Synonym for replace) -- (from CHAIN) require -- from CHAIN writeable: writable replaceable: replaceable ensure -- from CHAIN same_count: count = old count is_inserted: is_inserted (v) sequence_put (v: like item) -- Add v to end. -- (from SEQUENCE) require -- from COLLECTION extendible: extendible ensure -- from COLLECTION item_inserted: is_inserted (v) ensure then -- from SEQUENCE new_count: count = old count + 1 put_front (v: like item) -- Add v at beginning. -- Do not move cursor. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN extendible: extendible ensure -- from DYNAMIC_CHAIN new_count: count = old count + 1 item_inserted: first = v put_i_th (v: like item; i: INTEGER_32) -- Put v at i-th position. -- (from CHAIN) require -- from TABLE valid_key: valid_index (i) require -- from TABLE valid_key: valid_index (i) ensure -- from TABLE inserted: i_th (i) = v put_left (v: like item) -- Add v to the left of cursor position. -- Do not move cursor. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN extendible: extendible not_before: not before ensure -- from DYNAMIC_CHAIN new_count: count = old count + 1 new_index: index = old index + 1 put_right (v: like item) -- Add v to the right of cursor position. -- Do not move cursor. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN extendible: extendible not_after: not after ensure -- from DYNAMIC_CHAIN new_count: count = old count + 1 same_index: index = old index replace (v: G) -- Replace current item by v. -- (from ACTIVE) require -- from ACTIVE writable: writable replaceable: replaceable ensure -- from ACTIVE item_replaced: item = v feature -- Removal prune (v: like 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 item) -- Remove all occurrences of v. -- (Reference or object equality, -- based on object_comparison.) -- Leave structure exhausted. -- (from DYNAMIC_CHAIN) require -- from COLLECTION prunable: prunable ensure -- from COLLECTION no_more_occurrences: not has (v) ensure then -- from DYNAMIC_CHAIN is_exhausted: exhausted remove -- Remove item at cursor position. -- Move cursor to right neighbor (cyclically). -- If removed item was at current starting position, -- move starting position to right neighbor. -- (from CIRCULAR) require -- from ACTIVE prunable: prunable writable: writable remove_i_th (i: INTEGER_32) -- Remove item at index i. -- Move cursor to next neighbor (or after if no next neighbor) if it is at i-th position. -- Do not change cursor otherwise. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_TABLE prunable: prunable valid_key: valid_index (i) ensure then -- from DYNAMIC_CHAIN new_count: count = old count - 1 same_index_if_below: index <= i implies index = old index new_index_if_above: index > i implies index = old index - 1 same_leading_items: across old twin as c all c.target_index < i implies c.item = i_th (c.target_index) end same_trailing_items: across old twin as c all c.target_index > i implies c.item = i_th (c.target_index - 1) end remove_left -- Remove item to the left of cursor position. -- Do not move cursor. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN left_exists: index > 1 ensure -- from DYNAMIC_CHAIN new_count: count = old count - 1 new_index: index = old index - 1 remove_right -- Remove item to the right of cursor position. -- Do not move cursor. -- (from DYNAMIC_CHAIN) require -- from DYNAMIC_CHAIN right_exists: index < count ensure -- from DYNAMIC_CHAIN new_count: count = old count - 1 same_index: index = old index wipe_out -- Remove all items. -- (from DYNAMIC_CHAIN) require -- from COLLECTION prunable: prunable ensure -- from COLLECTION wiped_out: is_empty feature -- Transformation swap (i: INTEGER_32) -- Exchange item at i-th position with item -- at cursor position. -- (from CHAIN) require -- from CHAIN not_off: not off valid_index: valid_index (i) ensure -- from CHAIN swapped_to_item: item = old i_th (i) swapped_from_item: i_th (i) = old item feature -- Conversion linear_representation: LINEAR [G] -- Representation as a linear structure -- (from LINEAR) require -- from CONTAINER True feature -- Duplication copy (other: DYNAMIC_CIRCULAR [G]) -- Update current object using fields of object attached -- to other, so as to yield equal objects. -- (from ANY) require -- from ANY other_not_void: other /= Void type_identity: same_type (other) ensure -- from ANY is_equal: Current ~ other frozen deep_copy (other: DYNAMIC_CIRCULAR [G]) -- Effect equivalent to that of: -- copy (other . deep_twin) -- (from ANY) require -- from ANY other_not_void: other /= Void ensure -- from ANY deep_equal: deep_equal (Current, other) frozen deep_twin: DYNAMIC_CIRCULAR [G] -- New object structure recursively duplicated from Current. -- (from ANY) ensure -- from ANY deep_twin_not_void: Result /= Void deep_equal: deep_equal (Current, Result) frozen standard_copy (other: DYNAMIC_CIRCULAR [G]) -- Copy every field of other onto corresponding field -- of current object. -- (from ANY) require -- from ANY other_not_void: other /= Void type_identity: same_type (other) ensure -- from ANY is_standard_equal: standard_is_equal (other) frozen standard_twin: DYNAMIC_CIRCULAR [G] -- New object field-by-field identical to other. -- Always uses default copying semantics. -- (from ANY) ensure -- from ANY standard_twin_not_void: Result /= Void equal: standard_equal (Result, Current) frozen twin: DYNAMIC_CIRCULAR [G] -- New object equal to Current -- twin calls copy; to change copying/twinning semantics, redefine copy. -- (from ANY) ensure -- from ANY twin_not_void: Result /= Void is_equal: Result ~ Current feature -- Basic operations frozen default: detachable DYNAMIC_CIRCULAR [G] -- Default value of object's type -- (from ANY) frozen default_pointer: POINTER -- Default value of type POINTER -- (Avoid the need to write p.default for -- some p of type POINTER.) -- (from ANY) ensure -- from ANY instance_free: class default_rescue -- Process exception for routines with no Rescue clause. -- (Default: do nothing.) -- (from ANY) frozen do_nothing -- Execute a null action. -- (from ANY) ensure -- from ANY instance_free: class feature -- Iteration do_all (action: PROCEDURE [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 [G]; test: FUNCTION [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_exists: test /= Void for_all (test: FUNCTION [G, BOOLEAN]): BOOLEAN -- Is test true for all items? -- Semantics not guaranteed if test changes the structure; -- in such a case, apply iterator to clone of structure instead. -- (from LINEAR) require -- from TRAVERSABLE test_exists: test /= Void ensure then -- from LINEAR empty: is_empty implies Result there_exists (test: FUNCTION [G, BOOLEAN]): BOOLEAN -- Is test true for at least one item? -- Semantics not guaranteed if test changes the structure; -- in such a case, apply iterator to clone of structure instead. -- (from LINEAR) require -- from TRAVERSABLE test_exists: test /= Void feature -- Output Io: STD_FILES -- Handle to standard file setup -- (from ANY) ensure -- from ANY instance_free: class io_not_void: Result /= Void out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) ensure -- from ANY out_not_void: Result /= Void print (o: detachable ANY) -- Write terse external representation of o -- on standard output. -- (from ANY) ensure -- from ANY instance_free: class frozen tagged_out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) ensure -- from ANY tagged_out_not_void: Result /= Void feature -- Platform Operating_environment: OPERATING_ENVIRONMENT -- Objects available from the operating system -- (from ANY) ensure -- from ANY instance_free: class operating_environment_not_void: Result /= Void invariant -- from CIRCULAR not_before_unless_empty: before implies is_empty not_after_unless_empty: after implies is_empty not_off_unless_empty: off implies is_empty -- from CHAIN non_negative_index: index >= 0 index_small_enough: index <= count + 1 off_definition: off = ((index = 0) or (index = count + 1)) isfirst_definition: isfirst = ((not is_empty) and (index = 1)) islast_definition: islast = ((not is_empty) and (index = count)) item_corresponds_to_index: (not off) implies (item = i_th (index)) -- from ACTIVE writable_constraint: writable implies readable empty_constraint: is_empty implies (not readable) and (not writable) -- from ANY reflexive_equality: standard_is_equal (Current) reflexive_conformance: conforms_to (Current) -- from READABLE_INDEXABLE consistent_boundaries: Lower <= count or else Lower = count + 1 -- from BILINEAR not_both: not (after and before) before_constraint: before implies off -- from LINEAR after_constraint: after implies off -- from TRAVERSABLE empty_constraint: is_empty implies off -- from FINITE empty_definition: is_empty = (count = 0) note copyright: "Copyright (c) 1984-2018, Eiffel Software and others" license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)" source: "[ Eiffel Software 5949 Hollister Ave., Goleta, CA 93117 USA Telephone 805-685-1006, Fax 805-685-6869 Website http://www.eiffel.com Customer support http://support.eiffel.com ]" end -- class DYNAMIC_CIRCULAR
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