note
	description: "[
		Access to command-line arguments. This class 
		may be used as ancestor by classes needing its facilities.
	]"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2018-05-18 08:50:43 +0000 (Fri, 18 May 2018) $"
	revision: "$Revision: 101749 $"

class 
	ARGUMENTS_32

inherit
	ITERABLE [IMMUTABLE_STRING_32]

create 
	default_create

feature -- Access

	argument (i: INTEGER_32): IMMUTABLE_STRING_32
			-- i-th argument of command that started system execution
			-- (the command name if i = 0).
		require
			index_large_enough: i >= 0
			index_small_enough: i <= argument_count
		do
			Result := Internal_argument_array.item (i)
		ensure
			instance_free: class
			argument_not_void: Result /= Void
		end

	argument_array: ARRAY [IMMUTABLE_STRING_32]
			-- Array containing command name (position 0) and arguments.
			-- A new instance at each query.
		do
			Result := Internal_argument_array.twin
		ensure
			instance_free: class
			argument_array_not_void: Result /= Void
			argument_array_compare_objects: Result.object_comparison
		end

	Command_line: IMMUTABLE_STRING_32
			-- Full command line: Command_name followed by arguments.
		local
			i, n: INTEGER_32
			l_result: STRING_32
		once
			n := argument_count
			create l_result.make (Command_name.count + n * 10)
			from
				i := 0
			until
				i > n
			loop
				if i > 0 then
					l_result.append_character (' '.to_character_32)
				end;
				l_result.append (argument (i))
				i := i + 1
			end
			create Result.make_from_string (l_result)
		ensure
			instance_free: class
				Result.count >= Command_name.count
		end

	Command_name: IMMUTABLE_STRING_32
			-- Name of command that started system execution.
		once
			Result := argument (0)
		ensure
			instance_free: class
			definition: Result.same_string (argument (0))
		end
	
feature -- Access: Cursor

	new_cursor: ITERATION_CURSOR [IMMUTABLE_STRING_32]
			-- Fresh cursor associated with current structure
		do
			Result := Internal_argument_array.new_cursor
		ensure then
			instance_free: class
		end
	
feature -- Status report

	index_of_word_option (opt: READABLE_STRING_GENERAL): INTEGER_32
			-- Does command line specify word option opt and, if so,
			-- at what position?
			-- If one of the arguments in list of space-separated arguments
			-- is Xopt, where X is the current Option_sign,
			-- then index of this argument in list;
			-- else 0.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		local
			i: INTEGER_32
		do
			from
				i := 1
			until
				i > argument_count or else option_word_equal (Internal_argument_array.item (i), opt)
			loop
				i := i + 1
			end
			if i <= argument_count then
				Result := i
			end
		ensure
			instance_free: class
		end

	index_of_beginning_with_word_option (opt: READABLE_STRING_GENERAL): INTEGER_32
			-- Does command line specify argument beginning with word
			-- option opt and, if so, at what position?
			-- If one of the arguments in list of space-separated arguments
			-- is Xoptxx, where X is the current Option_sign, 'xx'
			-- is arbitrary, possibly empty sequence of characters,
			-- then index of this argument in list;
			-- else 0.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		local
			i: INTEGER_32
		do
			from
				i := 1
			until
				i > argument_count or else option_word_begins_with (Internal_argument_array.item (i), opt)
			loop
				i := i + 1
			end
			if i <= argument_count then
				Result := i
			end
		ensure
			instance_free: class
		end

	index_of_character_option (o: CHARACTER_32): INTEGER_32
			-- Does command line specify character option o and, if so,
			-- at what position?
			-- If one of the space-separated arguments is of the form Xxxoyy,
			-- where X is the current Option_sign, xx and yy
			-- are arbitrary, possibly empty sequences of characters,
			-- then index of this argument in list of arguments;
			-- else 0.
		require
			o_non_null: o /= '%U'.to_character_32
		local
			i: INTEGER_32
		do
			from
				i := 1
			until
				i > argument_count or else option_character_equal (Internal_argument_array.item (i), o)
			loop
				i := i + 1
			end
			if i <= argument_count then
				Result := i
			end
		ensure
			instance_free: class
		end

	separate_character_option_value (o: CHARACTER_32): detachable IMMUTABLE_STRING_32
			-- The value, if any, specified after character option o on
			-- the command line.
			-- This is one of the following (where X is the current
			-- Option_sign, xx and 'yy' are arbitrary, possibly empty
			-- sequences of characters):
			--   val if command line includes two consecutive arguments
			--	   of the form Xxxoyy and val respectively.
			--   Empty string if command line includes argument Xxxoyy, which is
			--	   either last argument or followed by argument starting with X.
			--   Void if there is no argument of the form Xxxoyy.
		require
			o_non_null: o /= '%U'.to_character_32
		local
			p: INTEGER_32
		do
			p := index_of_character_option (o)
			if p /= 0 then
				if p = argument_count or else Internal_argument_array.item (p + 1).item (1) = Option_sign.item then
					create Result.make_empty
				else
					Result := Internal_argument_array.item (p + 1)
				end
			end
		ensure
			instance_free: class
		end

	separate_word_option_value (opt: READABLE_STRING_GENERAL): detachable IMMUTABLE_STRING_32
			-- The value, if any, specified after word option opt on the
			-- command line.
			-- This is one of the following (where X is the current Option_sign):
			--   val if command line includes two consecutive arguments
			--	   of the form Xopt and val respectively.
			--   Empty string if command line includes argument Xopt, which is
			--	   either last argument or followed by argument starting with X.
			--   Void if no Xopt argument.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		local
			p: INTEGER_32
		do
			p := index_of_word_option (opt)
			if p /= 0 then
				if p = argument_count or else Internal_argument_array.item (p + 1).item (1) = Option_sign.item then
					create Result.make_empty
				else
					Result := Internal_argument_array.item (p + 1)
				end
			end
		ensure
			instance_free: class
		end

	coalesced_character_option_value (o: CHARACTER_32): detachable IMMUTABLE_STRING_32
			-- The value, if any, specified for character option o on
			-- the command line.
			-- Defined as follows (where 'X' is the current 'option_sign' and
			-- 'xx' is an arbitrary, possibly empty sequence of characters):
			--   val if command line includes an argument of the form Xxxoval
			--	   (this may be an empty string if argument is just Xxxo).
			--   Void otherwise.
		require
			o_non_null: o /= '%U'.to_character_32
		local
			p: INTEGER_32
		do
			p := index_of_character_option (o)
			if p /= 0 then
				Result := Internal_argument_array.item (p)
				if Option_sign.item = '%U'.to_character_32 then
					Result := Result.shared_substring (Result.index_of (o, 1) + 1, Result.count)
				else
					Result := Result.shared_substring (Result.index_of (o, 1) + 2, Result.count)
				end
			end
		ensure
			instance_free: class
		end

	coalesced_word_option_value (opt: READABLE_STRING_GENERAL): detachable IMMUTABLE_STRING_32
			-- The value, if any, specified for word option opt on the
			-- command line.
			-- Defined as follows (where X is the current Option_sign):
			--   val if command line includes an argument of the form Xoptval
			--	   (this may be an empty string if argument is just Xopt).
			--   Void otherwise.
		require
			opt_non_void: opt /= Void
			opt_meaningful: not opt.is_empty
		local
			p: INTEGER_32
		do
			p := index_of_beginning_with_word_option (opt)
			if p /= 0 then
				Result := Internal_argument_array.item (p)
				if Option_sign.item = '%U'.to_character_32 then
					Result := Result.shared_substring (opt.count + 1, Result.count)
				else
					Result := Result.shared_substring (opt.count + 2, Result.count)
				end
			end
		ensure
			instance_free: class
		end

	Option_sign: CELL [CHARACTER_32]
			-- The character used to signal options on the command line.
			-- This can be '%U' if no sign is necessary for the argument
			-- to be an option
			-- Default is '-'
		once
			create Result.put ('-'.to_character_32)
		ensure
			instance_free: class
		end
	
feature -- Status setting

	set_option_sign (c: CHARACTER_32)
			-- Make c the option sign.
			-- Use'%U' if no sign is necessary for the argument to
			-- be an option.
		do
			Option_sign.put (c)
		ensure
			instance_free: class
		end
	
feature -- Measurement

	argument_count: INTEGER_32
			-- Number of arguments given to command that started
			-- system execution (command name does not count).
		external
			"built_in static"
		ensure
			instance_free: class
			argument_count_positive: Result >= 0
		end
	
feature {NONE} -- Implementation

	option_word_equal (arg, w: READABLE_STRING_GENERAL): BOOLEAN
			-- Is arg equal to the word option w in a case sensitive manner?
		require
			arg_not_void: arg /= Void
			w_not_void: w /= Void
		do
			if Option_sign.item = '%U'.to_character_32 then
				Result := arg.same_string (w)
			elseif not arg.is_empty and then arg.item (1) = Option_sign.item then
				Result := arg.substring (2, arg.count).same_string (w)
			end
		ensure
			instance_free: class
		end

	option_word_begins_with (arg, w: READABLE_STRING_GENERAL): BOOLEAN
			-- Does arg begin with the word option w in a case sensitive manner?
		require
			arg_not_void: arg /= Void
			w_not_void: w /= Void
		do
			if Option_sign.item = '%U'.to_character_32 and then arg.count >= w.count then
				Result := arg.substring (1, w.count).same_string (w)
			elseif arg.item (1) = Option_sign.item and then arg.count > w.count then
				Result := arg.substring (2, w.count + 1).same_string (w)
			end
		ensure
			instance_free: class
		end

	option_character_equal (arg: READABLE_STRING_GENERAL; c: CHARACTER_32): BOOLEAN
			-- Does arg contain the character option c?
		require
			arg_not_void: arg /= Void
		do
			if Option_sign.item = '%U'.to_character_32 then
				Result := arg.has (c)
			elseif arg.item (1) = Option_sign.item then
				Result := arg.substring (2, arg.count).has (c)
			end
		ensure
			instance_free: class
		end

	Internal_argument_array: ARRAY [IMMUTABLE_STRING_32]
			-- Array containing command name (position 0) and arguments.
		local
			i: INTEGER_32
		once
			from
				create Result.make_filled (create {IMMUTABLE_STRING_32}.make_empty, 0, argument_count);
				Result.compare_objects
			until
				i > argument_count
			loop
				Result.put (i_th_argument_string (i), i)
				i := i + 1
			end
		ensure
			instance_free: class
			internal_argument_array_not_void: Result /= Void
			internal_argument_array_compare_objects: Result.object_comparison
		end

	i_th_argument_string (i: INTEGER_32): IMMUTABLE_STRING_32
			-- Underlying string holding the argument at position i.
		require
			index_large_enough: i >= 0
			index_small_enough: i <= argument_count
		local
			l_str: NATIVE_STRING
			l_ptr: POINTER
		do
			create l_str.make_empty (0)
			l_ptr := i_th_argument_pointer (i)
			if l_ptr /= default_pointer then
				l_str.set_shared_from_pointer (l_ptr)
				create Result.make_from_string (l_str.string)
			else
				create Result.make_empty
			end
		ensure
			instance_free: class
		end

	i_th_argument_pointer (i: INTEGER_32): POINTER
			-- Underlying pointer holding the argument at position i.
		require
			index_large_enough: i >= 0
			index_small_enough: i <= argument_count
		external
			"built_in static"
		ensure
			instance_free: class
		end
	
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 ARGUMENTS_32

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