indexing
	description: "Path name abstraction"
	library: "Free implementation of ELKS library"
	copyright: "Copyright (c) 1986-2008, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see forum.txt)"
	date: "$Date: 2008-05-23 17:24:07 -0700 (Fri, 23 May 2008) $"
	revision: "$Revision: 170 $"

deferred class interface
	PATH_NAME


feature -- Initialization

	make
			-- Create path name object.

	make_from_string (p: STRING_8)
			-- Create path name object and initialize it with the
			-- path name `p'
		require
			path_not_void: p /= Void
		ensure
			valid_file_name: is_valid
	
feature -- Access

	string: STRING_8
			-- New STRING_8 having same character sequence as `Current'.
			-- (from STRING_8)
		ensure -- from STRING_8
			string_not_void: Result /= Void
			string_type: Result.same_type (create {STRING_8}.make_empty)
			first_item: count > 0 implies Result.item (1) = item (1)
			recurse: count > 1 implies Result.substring (2, count).is_equal (substring (2, count).string)
	
feature -- Comparison

	is_equal (other: like Current): BOOLEAN
			-- Is the path name equal to `other'?
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other.is_equal (Current)
			consistent: standard_is_equal (other) implies Result
		ensure then -- from COMPARABLE
			trichotomy: Result = (not (Current < other) and not (other < Current))
	
feature -- Status report

	is_directory_name_valid (dir_name: STRING_8): BOOLEAN
			-- Is `dir_name' a valid subdirectory part for the operating system?
		require
			exists: dir_name /= Void

	is_empty: BOOLEAN
			-- Is structure empty?
			-- (from FINITE)
		require -- from  CONTAINER
			True
		require -- from  STRING_GENERAL
			True

	is_valid: BOOLEAN
			-- Is the path name valid for the operating system?

	is_volume_name_valid (vol_name: STRING_8): BOOLEAN
			-- Is `vol_name' a valid volume name for the operating system?
		require
			exists: vol_name /= Void

	prunable: BOOLEAN
			-- May items be removed? (Answer: yes.)
			-- (from STRING_8)
	
feature -- Status setting

	extend (directory_name: STRING_8)
			-- Append the subdirectory `directory_name' to the path name.
			-- Was declared in PATH_NAME as synonym of set_subdirectory.
		require
			string_exists: directory_name /= Void
			valid_directory_name: is_directory_name_valid (directory_name)
		ensure
			valid_file_name: is_valid

	extend_from_array (directories: ARRAY [STRING_8])
			-- Append the subdirectories from `directories' to the path name.
		require
			array_exists: directories /= Void and then not (directories.is_empty)
		ensure
			valid_file_name: is_valid

	set_directory (directory_name: STRING_8)
			-- Set the absolute directory part of the path name to `directory_name'.
		require
			string_exists: directory_name /= Void
			valid_directory_name: is_directory_name_valid (directory_name)
		ensure
			valid_file_name: is_valid

	set_subdirectory (directory_name: STRING_8)
			-- Append the subdirectory `directory_name' to the path name.
			-- Was declared in PATH_NAME as synonym of extend.
		require
			string_exists: directory_name /= Void
			valid_directory_name: is_directory_name_valid (directory_name)
		ensure
			valid_file_name: is_valid

	set_volume (volume_name: STRING_8)
			-- Set the volume part of the path name to `volume_name'.
		require
			string_exists: volume_name /= Void
			valid_volume_name: is_volume_name_valid (volume_name)
			empty_path_name: is_empty
		ensure
			valid_file_name: is_valid
	
feature -- Removal

	wipe_out
			-- Remove all characters.
			-- (from STRING_8)
		require -- from COLLECTION
			prunable: prunable
		ensure -- from COLLECTION
			wiped_out: is_empty
		ensure then -- from STRING_8
			is_empty: count = 0
			empty_capacity: capacity = 0
	
feature -- Conversion

	frozen to_c: ANY
			-- A reference to a C form of current string.
			-- Useful only for interfacing with C software.
			-- (from STRING_8)
		require -- from STRING_8
			not_is_dotnet: not {PLATFORM}.is_dotnet
	
feature -- Duplication

	frozen twin: PATH_NAME
			-- New object equal to `Current'
			-- twin calls copy; to change copying/twining semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result.is_equal (Current)
	
feature -- Output

	out: STRING_8
			-- Printable representation
			-- (from STRING_8)
		require -- from  ANY
			True
		ensure -- from ANY
			out_not_void: Result /= Void
		ensure then -- from STRING_8
			out_not_void: Result /= Void
			same_items: same_type ("") implies Result.same_string (Current)
	
invariant
		-- from STRING_8
	extendible: extendible
	compare_character: not object_comparison
	index_set_has_same_count: index_set.count = count
	area_not_void: area /= Void

		-- from COMPARABLE
	irreflexive_comparison: not (Current < Current)

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

		-- from INDEXABLE
	index_set_not_void: index_set /= Void

		-- from RESIZABLE
	increase_by_at_least_one: minimal_increase >= 1

		-- from BOUNDED
	valid_count: count <= capacity
	full_definition: full = (count = capacity)

		-- from FINITE
	empty_definition: is_empty = (count = 0)
	non_negative_count: count >= 0

end -- class PATH_NAME