note description: "Interface for character 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 interface KI_CHARACTER_INPUT_STREAM feature -- Access Any_: KL_ANY_ROUTINES -- Routines that ought to be in class ANY -- (from KL_IMPORTED_ANY_ROUTINES) ensure -- from KL_IMPORTED_ANY_ROUTINES instance_free: class any_routines_not_void: Result /= Void generating_type: TYPE [detachable KI_CHARACTER_INPUT_STREAM] -- 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 last_character: CHARACTER_8 -- Last item read -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM is_open_read: is_open_read not_end_of_input: not end_of_input last_string: STRING_8 -- Last string read -- (Note: this query always return the same object. -- Therefore a clone should be used if the result -- is to be kept beyond the next call to this feature. -- However last_string is not shared between file objects.) require is_open_read: is_open_read not_end_of_input: not end_of_input ensure last_string_not_void: Result /= Void string_type: Any_.same_types (Result, "") name: STRING_8 -- Name of input stream -- (from KI_INPUT_STREAM) ensure -- from KI_INPUT_STREAM name_not_void: Result /= Void 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 (other: KI_CHARACTER_INPUT_STREAM): 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: KI_CHARACTER_INPUT_STREAM): 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 (other: KI_CHARACTER_INPUT_STREAM): 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 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 end_of_input: BOOLEAN -- Has the end of input stream been reached? -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM is_open_read: is_open_read is_closable: BOOLEAN -- Can current input stream be closed? -- (from KI_INPUT_STREAM) ensure -- from KI_INPUT_STREAM is_open: Result implies is_open_read is_open_read: BOOLEAN -- Can items be read from input stream? -- (from KI_INPUT_STREAM) is_rewindable: BOOLEAN -- Can current input stream be rewound to return input from -- the beginning of the stream? -- (from KI_INPUT_STREAM) ensure -- from KI_INPUT_STREAM rewind_implies_open: Result implies is_open_read 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_unread_character (a_character: CHARACTER_8): BOOLEAN -- Can a_character be put back in input stream? feature -- Duplication copy (other: KI_CHARACTER_INPUT_STREAM) -- 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: KI_CHARACTER_INPUT_STREAM) -- 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: KI_CHARACTER_INPUT_STREAM -- 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: KI_CHARACTER_INPUT_STREAM) -- 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: KI_CHARACTER_INPUT_STREAM -- 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: KI_CHARACTER_INPUT_STREAM -- 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 close -- Try to close input stream if it is closable. Set -- is_open_read to false if operation was successful. -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM is_closable: is_closable frozen default: detachable KI_CHARACTER_INPUT_STREAM -- 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 rewind -- Move input position to the beginning of stream. -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM can_rewind: is_rewindable feature -- Input read_character -- Read the next item in input stream. -- Make the result available in last_item. -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM is_open_read: is_open_read not_end_of_input: not end_of_input read_string (nb: INTEGER_32) -- Read at most nb characters from input stream. -- Make the characters that have actually been read -- available in last_string. -- (Note that even if at least nb characters 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 nb_large_enough: nb > 0 ensure last_string_count_small_enough: not end_of_input implies last_string.count <= nb character_read: not end_of_input implies last_string.count > 0 read_to_buffer (a_buffer: KI_BUFFER [CHARACTER_8]; 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.) -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM 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 ensure -- from KI_INPUT_STREAM 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 read_to_string (a_string: STRING_8; pos, nb: INTEGER_32): INTEGER_32 -- Fill a_string, starting at position pos, with -- at most nb characters read from input stream. -- Return the number of characters actually read. -- (Note that even if at least nb characters 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_string_not_void: a_string /= Void valid_position: a_string.valid_index (pos) nb_large_enough: nb > 0 nb_small_enough: nb <= a_string.count - pos + 1 ensure nb_char_read_large_enough: Result >= 0 nb_char_read_small_enough: Result <= nb character_read: not end_of_input implies Result > 0 unread_character (an_item: CHARACTER_8) -- Put an_item back in input stream. -- This item will be read first by the next -- call to a read routine. -- (from KI_INPUT_STREAM) require -- from KI_INPUT_STREAM is_open_read: is_open_read an_item_valid: valid_unread_character (an_item) ensure -- from KI_INPUT_STREAM not_end_of_input: not end_of_input last_item_set: last_character = an_item 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 ANY reflexive_equality: standard_is_equal (Current) reflexive_conformance: conforms_to (Current) end -- class KI_CHARACTER_INPUT_STREAM
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