note
	description: "References to objects containing a character value"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2017-03-23 19:18:26 +0000 (Thu, 23 Mar 2017) $"
	revision: "$Revision: 100033 $"

class 
	CHARACTER_8_REF

inherit
	COMPARABLE
		redefine
			out,
			is_equal
		end

	HASHABLE
		redefine
			out,
			is_equal
		end

create 
	default_create

feature -- Access

	item: CHARACTER_8
			-- Character value


	code: INTEGER_32
		obsolete "Use `natural_32_code' instead. [2017-05-31]"
			-- Associated integer value
		do
			Result := item.code
		ensure
			code_non_negatif: Result >= 0
			code_in_range: Result >= Min_value and Result <= Max_value
		end

	natural_32_code: NATURAL_32
			-- Associated natural value
		do
			Result := item.code.to_natural_32
		end

	hash_code: INTEGER_32
			-- Hash code value
		do
			Result := natural_32_code.hash_code
		end

	Min_value: INTEGER_32 = 0

	Max_value: INTEGER_32 = 255

	Max_ascii_value: INTEGER_32 = 127
			-- Bounds for integer representation of characters (ASCII)
	
feature -- Comparison

	is_less alias "<" (other: like Current): BOOLEAN
			-- Is other greater than current character?
		do
			Result := natural_32_code < other.natural_32_code
		ensure then
			definition: Result = (natural_32_code < other.natural_32_code)
		end

	is_equal (other: like Current): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object and identical to it?
		do
			Result := other.item = item
		end
	
feature -- Basic routines

	plus alias "+" (incr: INTEGER_32): CHARACTER_8
			-- Add incr to the code of item
		require
			valid_increment: (item.code + incr).is_valid_character_8_code
		do
			Result := (item.code + incr).to_character_8
		ensure
			valid_result: Result |-| item = incr
		end

	minus alias "-" (decr: INTEGER_32): CHARACTER_8
			-- Subtract decr from the code of item
		require
			valid_decrement: (item.code - decr).is_valid_character_8_code
		do
			Result := (item.code - decr).to_character_8
		ensure
			valid_result: item |-| Result = decr
		end

	difference alias "|-|" (other: CHARACTER_8): INTEGER_32
			-- Difference between the codes of item and other
		do
			Result := item.code - other.code
		ensure
			valid_result: other + Result = item
		end

	next: CHARACTER_8
			-- Next character
		require
			valid_character: (item.code + 1).is_valid_character_8_code
		do
			Result := item + 1
		ensure
			valid_result: Result |-| item = 1
		end

	previous: CHARACTER_8
			-- Previous character
		require
			valid_character: (item.code - 1).is_valid_character_8_code
		do
			Result := item - 1
		ensure
			valid_result: Result |-| item = -1
		end
	
feature -- Element change

	set_item (c: CHARACTER_8)
			-- Make c the item value.
		do
			item := c
		end
	
feature -- Output

	out: STRING_8
			-- Printable representation of character
		do
			create Result.make (1)
			Result.append_character (item)
		end
	
feature {NONE} -- Initialization

	make_from_reference (v: CHARACTER_8_REF)
			-- Initialize Current with v.item.
		require
			v_not_void: v /= Void
		do
			set_item (v.item)
		ensure
			item_set: item = v.item
		end
	
feature -- Conversion

	to_reference: CHARACTER_8_REF
			-- Associated reference of Current
		do
			create Result
			Result.set_item (item)
		ensure
			to_reference_not_void: Result /= Void
		end

	to_character_8: CHARACTER_8
			-- Associated character in 8 bit version
		do
			Result := item
		end

	to_character_32: CHARACTER_32
			-- Associated character in 32 bit version
		do
			Result := item.to_character_32
		end

	as_upper: CHARACTER_8
			-- Uppercase value of item
			-- Returns item if not is_lower
			-- Was declared in CHARACTER_8_REF as synonym of upper.
		do
			if is_lower then
				Result := (item.code - ('a').code + ('A').code).to_character_8
			else
				Result := item
			end
		end

	upper: CHARACTER_8
			-- Uppercase value of item
			-- Returns item if not is_lower
			-- Was declared in CHARACTER_8_REF as synonym of as_upper.
		do
			if is_lower then
				Result := (item.code - ('a').code + ('A').code).to_character_8
			else
				Result := item
			end
		end

	as_lower: CHARACTER_8
			-- Lowercase value of item
			-- Returns item if not is_upper
			-- Was declared in CHARACTER_8_REF as synonym of lower.
		do
			if is_upper then
				Result := (item.code - ('A').code + ('a').code).to_character_8
			else
				Result := item
			end
		end

	lower: CHARACTER_8
			-- Lowercase value of item
			-- Returns item if not is_upper
			-- Was declared in CHARACTER_8_REF as synonym of as_lower.
		do
			if is_upper then
				Result := (item.code - ('A').code + ('a').code).to_character_8
			else
				Result := item
			end
		end
	
feature -- Status report

	is_alpha: BOOLEAN
			-- Is item alphabetic?
			-- Alphabetic is is_upper or is_lower
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag)) > 0
		end

	is_upper: BOOLEAN
			-- Is item uppercase?
		do
			Result := (character_types (item.code) & Is_upper_flag) > 0
		end

	is_lower: BOOLEAN
			-- Is item lowercase?
		do
			Result := (character_types (item.code) & Is_lower_flag) > 0
		end

	is_digit: BOOLEAN
			-- Is item a digit?
			-- A digit is one of 0123456789
		do
			Result := (character_types (item.code) & Is_digit_flag) > 0
		end

	is_hexa_digit: BOOLEAN
			-- Is item an hexadecimal digit?
			-- A digit is one of 0123456789ABCDEFabcedf
		do
			Result := (character_types (item.code) & (Is_hexa_digit_flag | Is_digit_flag)) > 0
		end

	is_space: BOOLEAN
			-- Is item a white space?
		do
			Result := (character_types (item.code) & Is_white_space_flag) > 0
		end

	is_punctuation: BOOLEAN
			-- Is item a punctuation?
		do
			Result := (character_types (item.code) & Is_punctuation_flag) > 0
		end

	is_alpha_numeric: BOOLEAN
			-- Is item alphabetic or a digit?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag)) > 0
		end

	is_printable: BOOLEAN
			-- Is item a printable character including space?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag | Is_punctuation_flag | Is_space_flag)) > 0
		end

	is_graph: BOOLEAN
			-- Is item a printable character except space?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag | Is_punctuation_flag)) > 0
		end

	is_control: BOOLEAN
			-- Is item a control character?
		do
			Result := (character_types (item.code) & Is_control_flag) > 0
		end
	
feature {NONE} -- Implementation

	character_types (a_code: INTEGER_32): NATURAL_8
			-- Associated type for character of code a_code
		do
			if a_code < 256 then
				Result := Internal_character_types.item (a_code)
			end
		end

	Internal_character_types: SPECIAL [NATURAL_8]
			-- Array which stores the various type for the ASCII characters
		once
			create Result.make_empty (256)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag | Is_white_space_flag)
			Result.extend (Is_control_flag | Is_white_space_flag)
			Result.extend (Is_control_flag | Is_white_space_flag)
			Result.extend (Is_control_flag | Is_white_space_flag)
			Result.extend (Is_control_flag | Is_white_space_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_control_flag)
			Result.extend (Is_white_space_flag | Is_space_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_digit_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag | Is_hexa_digit_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_upper_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag | Is_hexa_digit_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_lower_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_punctuation_flag)
			Result.extend (Is_control_flag)
			Result.fill_with (0, 128, 255)
		ensure
			internal_character_types_not_void: Result /= Void
		end

	Is_upper_flag: NATURAL_8 = 1

	Is_lower_flag: NATURAL_8 = 2

	Is_digit_flag: NATURAL_8 = 4

	Is_white_space_flag: NATURAL_8 = 8

	Is_punctuation_flag: NATURAL_8 = 16

	Is_control_flag: NATURAL_8 = 32

	Is_hexa_digit_flag: NATURAL_8 = 64

	Is_space_flag: NATURAL_8 = 128
	
note
	copyright: "Copyright (c) 1984-2017, 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 CHARACTER_8_REF

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