note description: "Interface for input streams" library: "Gobo Eiffel Kernel Library" copyright: "Copyright (c) 2001-2018, Eric Bezault and others" license: "MIT License" date: "$Date: 2019-02-07 22:54:15 +0000 (Thu, 07 Feb 2019) $" revision: "$Revision: 102807 $" deferred class KI_INPUT_STREAM [G] feature {NONE} -- Initialization default_create -- Process instances of classes with no creation clause. -- (Default: do nothing.) -- (from ANY) do end feature -- Access generating_type: TYPE [detachable KI_INPUT_STREAM [G]] -- Type of current object -- (type of which it is a direct instance) -- (from ANY) external "built_in" ensure -- from ANY generating_type_not_void: Result /= Void end generator: STRING_8 -- Name of current object's generating class -- (base class of the type of which it is a direct instance) -- (from ANY) external "built_in" ensure -- from ANY generator_not_void: Result /= Void generator_not_empty: not Result.is_empty end last_item: G -- Last item read require is_open_read: is_open_read not_end_of_input: not end_of_input deferred end name: STRING_8 -- Name of input stream deferred ensure name_not_void: Result /= Void end 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) do if a = Void then Result := b = Void else Result := b /= Void and then a.is_deep_equal (b) end 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) end 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) do if a = Void then Result := b = Void else Result := b /= Void and then a.is_equal (b) end 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)) end frozen is_deep_equal (other: KI_INPUT_STREAM [G]): BOOLEAN -- Are Current and other attached to isomorphic object structures? -- (from ANY) require -- from ANY other_not_void: other /= Void external "built_in" 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) end is_equal (other: KI_INPUT_STREAM [G]): BOOLEAN -- Is other attached to an object considered -- equal to current object? -- (from ANY) require -- from ANY other_not_void: other /= Void external "built_in" ensure -- from ANY symmetric: Result implies other ~ Current consistent: standard_is_equal (other) implies Result end 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) do if a = Void then Result := b = Void else Result := b /= Void and then a.standard_is_equal (b) end 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)) end frozen standard_is_equal (other: KI_INPUT_STREAM [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 external "built_in" ensure -- from ANY same_type: Result implies same_type (other) symmetric: Result implies other.standard_is_equal (Current) end feature -- Status report 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 external "built_in" end end_of_input: BOOLEAN -- Has the end of input stream been reached? require is_open_read: is_open_read deferred end is_closable: BOOLEAN -- Can current input stream be closed? do Result := False ensure is_open: Result implies is_open_read end is_open_read: BOOLEAN -- Can items be read from input stream? deferred end is_rewindable: BOOLEAN -- Can current input stream be rewound to return input from -- the beginning of the stream? do Result := False ensure rewind_implies_open: Result implies is_open_read end 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 external "built_in" ensure -- from ANY definition: Result = (conforms_to (other) and other.conforms_to (Current)) end valid_unread_item (an_item: G): BOOLEAN -- Can an_item be put back in input stream? deferred end feature -- Duplication frozen clone (other: detachable ANY): like other obsolete "Use `twin' instead. [2017-05-31]" -- Void if other is void; otherwise new object -- equal to other -- -- For non-void other, clone calls copy; -- to change copying/cloning semantics, redefine copy. -- (from ANY) do if other /= Void then Result := other.twin end ensure -- from ANY instance_free: class equal: Result ~ other end copy (other: KI_INPUT_STREAM [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) external "built_in" ensure -- from ANY is_equal: Current ~ other end frozen deep_clone (other: detachable ANY): like other obsolete "Use `deep_twin' instead. [2017-05-31]" -- Void if other is void: otherwise, new object structure -- recursively duplicated from the one attached to other -- (from ANY) do if other /= Void then Result := other.deep_twin end ensure -- from ANY instance_free: class deep_equal: deep_equal (other, Result) end frozen deep_copy (other: KI_INPUT_STREAM [G]) -- Effect equivalent to that of: -- copy (other . deep_twin) -- (from ANY) require -- from ANY other_not_void: other /= Void do copy (other.deep_twin) ensure -- from ANY deep_equal: deep_equal (Current, other) end frozen deep_twin: KI_INPUT_STREAM [G] -- New object structure recursively duplicated from Current. -- (from ANY) external "built_in" ensure -- from ANY deep_twin_not_void: Result /= Void deep_equal: deep_equal (Current, Result) end frozen standard_clone (other: detachable ANY): like other obsolete "Use `standard_twin' instead. [2017-05-31]" -- Void if other is void; otherwise new object -- field-by-field identical to other. -- Always uses default copying semantics. -- (from ANY) do if other /= Void then Result := other.standard_twin end ensure -- from ANY instance_free: class equal: standard_equal (Result, other) end frozen standard_copy (other: KI_INPUT_STREAM [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) external "built_in" ensure -- from ANY is_standard_equal: standard_is_equal (other) end frozen standard_twin: KI_INPUT_STREAM [G] -- New object field-by-field identical to other. -- Always uses default copying semantics. -- (from ANY) external "built_in" ensure -- from ANY standard_twin_not_void: Result /= Void equal: standard_equal (Result, Current) end frozen twin: KI_INPUT_STREAM [G] -- New object equal to Current -- twin calls copy; to change copying/twinning semantics, redefine copy. -- (from ANY) external "built_in" ensure -- from ANY twin_not_void: Result /= Void is_equal: Result ~ Current end feature -- Basic operations frozen as_attached: attached KI_INPUT_STREAM [G] obsolete "Remove calls to this feature. [2017-05-31]" -- Attached version of Current. -- (Can be used during transitional period to convert -- non-void-safe classes to void-safe ones.) -- (from ANY) do Result := Current end close -- Try to close input stream if it is closable. Set -- is_open_read to false if operation was successful. require is_closable: is_closable do end frozen default: detachable KI_INPUT_STREAM [G] -- Default value of object's type -- (from ANY) do end frozen default_pointer: POINTER -- Default value of type POINTER -- (Avoid the need to write p.default for -- some p of type POINTER.) -- (from ANY) do ensure -- from ANY instance_free: class end default_rescue -- Process exception for routines with no Rescue clause. -- (Default: do nothing.) -- (from ANY) do end frozen do_nothing -- Execute a null action. -- (from ANY) do ensure -- from ANY instance_free: class end rewind -- Move input position to the beginning of stream. require can_rewind: is_rewindable do end feature -- Input read -- Read the next item in input stream. -- Make the result available in last_item. require is_open_read: is_open_read not_end_of_input: not end_of_input deferred end read_to_buffer (a_buffer: KI_BUFFER [G]; pos, nb: INTEGER_32): INTEGER_32 -- Fill a_buffer, starting at position pos, with -- at most nb items read from input stream. -- Return the number of items actually read. -- (Note that even if at least nb items are available -- in the input stream, there is no guarantee that they -- will all be read.) require is_open_read: is_open_read not_end_of_input: not end_of_input a_buffer_not_void: a_buffer /= Void pos_large_enough: pos >= 1 nb_large_enough: nb > 0 enough_space: (pos + nb - 1) <= a_buffer.count local i, end_pos: INTEGER_32 do end_pos := pos + nb - 1 from i := pos until i > end_pos loop read if not end_of_input then a_buffer.put (last_item, i) i := i + 1 else Result := i - pos - nb i := end_pos + 1 end end Result := Result + i - pos ensure nb_item_read_large_enough: Result >= 0 nb_item_read_small_enough: Result <= nb not_end_of_input: not end_of_input implies Result > 0 end unread (an_item: G) -- Put an_item back in input stream. -- This item will be read first by the next -- call to a read routine. require is_open_read: is_open_read an_item_valid: valid_unread_item (an_item) deferred ensure not_end_of_input: not end_of_input last_item_set: last_item = an_item end feature -- Output Io: STD_FILES -- Handle to standard file setup -- (from ANY) once create Result Result.set_output_default ensure -- from ANY instance_free: class io_not_void: Result /= Void end out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) do Result := tagged_out ensure -- from ANY out_not_void: Result /= Void end print (o: detachable ANY) -- Write terse external representation of o -- on standard output. -- (from ANY) do if o /= Void then Io.put_string (o.out) end ensure -- from ANY instance_free: class end frozen tagged_out: STRING_8 -- New string containing terse printable representation -- of current object -- (from ANY) external "built_in" ensure -- from ANY tagged_out_not_void: Result /= Void end feature -- Platform Operating_environment: OPERATING_ENVIRONMENT -- Objects available from the operating system -- (from ANY) once create Result ensure -- from ANY instance_free: class operating_environment_not_void: Result /= Void end feature {NONE} -- Retrieval frozen internal_correct_mismatch -- Called from runtime to perform a proper dynamic dispatch on correct_mismatch -- from MISMATCH_CORRECTOR. -- (from ANY) local l_msg: STRING_8 l_exc: EXCEPTIONS do if attached {MISMATCH_CORRECTOR} Current as l_corrector then l_corrector.correct_mismatch else create l_msg.make_from_string ("Mismatch: ") create l_exc l_msg.append (generating_type.name) l_exc.raise_retrieval_exception (l_msg) end end invariant -- from ANY reflexive_equality: standard_is_equal (Current) reflexive_conformance: conforms_to (Current) end -- class KI_INPUT_STREAM
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