indexing
	description: "Sequential files, viewed as persistent sequences of characters"
	status: "See notice at end of class"
	date: "$Date$"
	revision: "$Revision$"

deferred class interface
	FILE

feature -- Initialization

	make (fn: STRING)
			-- Create file object with fn as file name.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			file_named: name.is_equal (fn)
			file_closed: is_closed

	make_create_read_write (fn: STRING)
			-- Create file object with fn as file name
			-- and open file for both reading and writing;
			-- create it if it does not exist.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	make_open_append (fn: STRING)
			-- Create file object with fn as file name
			-- and open file in append-only mode.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_append: is_open_append

	make_open_read (fn: STRING)
			-- Create file object with fn as file name
			-- and open file in read mode.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_read: is_open_read

	make_open_read_append (fn: STRING)
			-- Create file object with fn as file name
			-- and open file for reading anywhere
			-- but writing at the end only.
			-- Create file if it does not exist.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_read: is_open_read
			open_append: is_open_append

	make_open_read_write (fn: STRING)
			-- Create file object with fn as file name
			-- and open file for both reading and writing.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	make_open_write (fn: STRING)
			-- Create file object with fn as file name
			-- and open file for writing;
			-- create it if it does not exist.
		require
			string_exists: fn /= void
			string_not_empty: not fn.is_empty
		ensure
			exists: exists
			open_write: is_open_write
	
feature -- Access

	access_date: INTEGER
			-- Time stamp of last access made to the inode.
		require
			file_exists: exists

	date: INTEGER
			-- Time stamp (time of last modification)
		require
			file_exists: exists

	descriptor: INTEGER
			-- File descriptor as used by the operating system.
		require -- from IO_MEDIUM
			valid_handle: descriptor_available
		require else
			file_opened: not is_closed

	descriptor_available: BOOLEAN

	file_info: UNIX_FILE_INFO
			-- Collected information about the file.

	file_pointer: POINTER
			-- File pointer as required in C

	group_id: INTEGER
			-- Group identification of owner
		require
			file_exists: exists

	has (v: like item): BOOLEAN
			-- Does structure include an occurrence of v?
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from LINEAR)
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not is_empty

	index: INTEGER
			-- Index of current position
			-- (from LINEAR)

	index_of (v: like item; i: INTEGER): INTEGER
			-- Index of i-th occurrence of v.
			-- 0 if none.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from LINEAR)
		require -- from LINEAR
			positive_occurrences: i > 0
		ensure -- from LINEAR
			non_negative_result: Result >= 0

	inode: INTEGER
			-- I-node number
		require
			file_exists: exists

	item: CHARACTER
			-- Current item
		require -- from TRAVERSABLE
			not_off: not off
		require -- from ACTIVE
			readable: readable

	links: INTEGER
			-- Number of links on file
		require
			file_exists: exists

	name: STRING
			-- File name

	occurrences (v: CHARACTER): INTEGER
			-- Number of times v appears.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from LINEAR)
		ensure -- from BAG
			non_negative_occurrences: Result >= 0

	owner_name: STRING
			-- Name of owner
		require
			file_exists: exists

	position: INTEGER
			-- Current cursor position.

	protection: INTEGER
			-- Protection mode, in decimal value
		require
			file_exists: exists

	retrieved: ANY
			-- Retrieved object structure
			-- To access resulting object under correct type,
			-- use assignment attempt.
			-- Will raise an exception (code Retrieve_exception)
			-- if content is not a stored Eiffel structure.
		require -- from IO_MEDIUM
			exists: exists
			is_open_read: is_open_read
			support_storable: support_storable
		ensure -- from IO_MEDIUM
			result_exists: Result /= void

	separator: CHARACTER
			-- ASCII code of character following last word read

	user_id: INTEGER
			-- User identification of owner
		require
			file_exists: exists
	
feature -- Measurement

	count: INTEGER
			-- Size in bytes (0 if no associated physical file)
	
feature -- Status report

	access_exists: BOOLEAN
			-- Does physical file exist?
			-- (Uses real UID.)

	after: BOOLEAN
			-- Is there no valid cursor position to the right of cursor position?

	before: BOOLEAN
			-- Is there no valid cursor position to the left of cursor position?

	changeable_comparison_criterion: BOOLEAN
			-- May object_comparison be changed?
			-- (Answer: yes by default.)
			-- (from CONTAINER)

	end_of_file: BOOLEAN
			-- Has an EOF been detected?
		require
			opened: not is_closed

	exhausted: BOOLEAN
			-- Has structure been completely explored?
			-- (from LINEAR)
		ensure -- from LINEAR
			exhausted_when_off: off implies Result

	exists: BOOLEAN
			-- Does physical file exist?
			-- (Uses effective UID.)
		ensure then
			unchanged_mode: mode = old mode

	extendible: BOOLEAN
			-- May new items be added?

	file_prunable: BOOLEAN
			-- May items be removed?

	file_readable: BOOLEAN
			-- Is there a current item that may be read?

	file_writable: BOOLEAN
			-- Is there a current item that may be modified?

	Full: BOOLEAN is False
			-- Is structure filled to capacity?

	is_access_executable: BOOLEAN
			-- Is file executable by real UID?
		require
			file_exists: exists

	is_access_owner: BOOLEAN
			-- Is file owned by real UID?
		require
			file_exists: exists

	is_access_readable: BOOLEAN
			-- Is file readable by real UID?
		require
			file_exists: exists

	is_access_writable: BOOLEAN
			-- Is file writable by real UID?
		require
			file_exists: exists

	is_block: BOOLEAN
			-- Is file a block special file?
		require
			file_exists: exists

	is_character: BOOLEAN
			-- Is file a character special file?
		require
			file_exists: exists

	is_closed: BOOLEAN
			-- Is file closed?

	is_creatable: BOOLEAN
			-- Is file creatable in parent directory?
			-- (Uses effective UID to check that parent is writable
			-- and file does not exist.)

	is_device: BOOLEAN
			-- Is file a device?
		require
			file_exists: exists

	is_directory: BOOLEAN
			-- Is file a directory?
		require
			file_exists: exists

	is_empty: BOOLEAN
			-- Is structure empty?
			-- (from FINITE)

	is_executable: BOOLEAN
			-- Is file executable?
			-- (Checks execute permission for effective UID.)
		require -- from IO_MEDIUM
			handle_exists: exists

	is_fifo: BOOLEAN
			-- Is file a named pipe?
		require
			file_exists: exists

	is_inserted (v: CHARACTER): BOOLEAN
			-- Has v been inserted by the most recent insertion?
			-- (By default, the value returned is equivalent to calling
			-- `has (v)'. However, descendants might be able to provide more
			-- efficient implementations.)
			-- (from COLLECTION)

	is_open_append: BOOLEAN
			-- Is file open for appending?

	is_open_read: BOOLEAN
			-- Is file open for reading?

	is_open_write: BOOLEAN
			-- Is file open for writing?

	is_owner: BOOLEAN
			-- Is file owned by effective UID?
		require
			file_exists: exists

	is_plain: BOOLEAN
			-- Is file a plain file?
		require
			file_exists: exists

	is_plain_text: BOOLEAN
			-- Is file reserved for text (character sequences)?
			-- (from IO_MEDIUM)

	is_readable: BOOLEAN
			-- Is file readable?
			-- (Checks permission for effective UID.)
		require -- from IO_MEDIUM
			handle_exists: exists

	is_setgid: BOOLEAN
			-- Is file setgid?
		require
			file_exists: exists

	is_setuid: BOOLEAN
			-- Is file setuid?
		require
			file_exists: exists

	is_socket: BOOLEAN
			-- Is file a named socket?
		require
			file_exists: exists

	is_sticky: BOOLEAN
			-- Is file sticky (for memory swaps)?
		require
			file_exists: exists

	is_symlink: BOOLEAN
			-- Is file a symbolic link?
		require
			file_exists: exists

	is_writable: BOOLEAN
			-- Is file writable?
			-- (Checks write permission for effective UID.)
		require -- from IO_MEDIUM
			handle_exists: exists

	last_character: CHARACTER
			-- Last character read by read_character
			-- (from IO_MEDIUM)

	last_double: DOUBLE
			-- Last double read by read_double
			-- (from IO_MEDIUM)

	last_integer: INTEGER
			-- Last integer read by read_integer
			-- (from IO_MEDIUM)

	last_real: REAL
			-- Last real read by read_real
			-- (from IO_MEDIUM)

	last_string: STRING
			-- Last string read
			-- (from IO_MEDIUM)

	object_comparison: BOOLEAN
			-- Must search operations use equal rather than =
			-- for comparing references? (Default: no, use =.)
			-- (from CONTAINER)

	off: BOOLEAN
			-- Is there no item?

	readable: BOOLEAN
			-- Is there a current item that may be read?
			-- (from SEQUENCE)
		require -- from  ACTIVE
			True
		require -- from IO_MEDIUM
			handle_exists: exists

	support_storable: BOOLEAN
			-- Can medium be used to store an Eiffel object?
			-- (from IO_MEDIUM)

	writable: BOOLEAN
			-- Is there a current item that may be modified?
			-- (from SEQUENCE)
	
feature -- Status setting

	close
			-- Close file.
		require -- from IO_MEDIUM
			medium_is_open: not is_closed
		ensure then
			is_closed: is_closed

	compare_objects
			-- Ensure that future search operations will use equal
			-- rather than = for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion
		ensure -- from CONTAINER
			object_comparison

	compare_references
			-- Ensure that future search operations will use =
			-- rather than equal for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion
		ensure -- from CONTAINER
			reference_comparison: not object_comparison

	create_read_write
			-- Open file in read and write mode;
			-- create it if it does not exist.
		require
			is_closed: is_closed
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	fd_open_append (fd: INTEGER)
			-- Open file of descriptor fd in append mode.
		ensure
			exists: exists
			open_append: is_open_append

	fd_open_read (fd: INTEGER)
			-- Open file of descriptor fd in read-only mode.
		ensure
			exists: exists
			open_read: is_open_read

	fd_open_read_append (fd: INTEGER)
			-- Open file of descriptor fd
			-- in read and write-at-end mode.
		ensure
			exists: exists
			open_read: is_open_read
			open_append: is_open_append

	fd_open_read_write (fd: INTEGER)
			-- Open file of descriptor fd in read-write mode.
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	fd_open_write (fd: INTEGER)
			-- Open file of descriptor fd in write mode.
		ensure
			exists: exists
			open_write: is_open_write

	open_append
			-- Open file in append-only mode;
			-- create it if it does not exist.
		require
			is_closed: is_closed
		ensure
			exists: exists
			open_append: is_open_append

	open_read
			-- Open file in read-only mode.
		require
			is_closed: is_closed
		ensure
			exists: exists
			open_read: is_open_read

	open_read_append
			-- Open file in read and write-at-end mode;
			-- create it if it does not exist.
		require
			is_closed: is_closed
		ensure
			exists: exists
			open_read: is_open_read
			open_append: is_open_append

	open_read_write
			-- Open file in read and write mode.
		require
			is_closed: is_closed
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	open_write
			-- Open file in write-only mode;
			-- create it if it does not exist.
		ensure
			exists: exists
			open_write: is_open_write

	recreate_read_write (fname: STRING)
			-- Reopen in read-write mode with file of name fname;
			-- create file if it does not exist.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	reopen_append (fname: STRING)
			-- Reopen in append mode with file of name fname;
			-- create file if it does not exist.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_append: is_open_append

	reopen_read (fname: STRING)
			-- Reopen in read-only mode with file of name fname;
			-- create file if it does not exist.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_read: is_open_read

	reopen_read_append (fname: STRING)
			-- Reopen in read and write-at-end mode with file
			-- of name fname; create file if it does not exist.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_read: is_open_read
			open_append: is_open_append

	reopen_read_write (fname: STRING)
			-- Reopen in read-write mode with file of name fname.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_read: is_open_read
			open_write: is_open_write

	reopen_write (fname: STRING)
			-- Reopen in write-only mode with file of name fname;
			-- create file if it does not exist.
		require
			is_open: not is_closed
			valid_name: fname /= void
		ensure
			exists: exists
			open_write: is_open_write
	
feature -- Cursor movement

	back
			-- Go back one position.
		require -- from BILINEAR
			not_before: not before

	finish
			-- Go to last position.
		require -- from  LINEAR
			True
		require else
			file_opened: not is_closed

	forth
			-- Go to next position.
		require -- from LINEAR
			not_after: not after
		require else
			file_opened: not is_closed

	go (abs_position: INTEGER)
			-- Go to the absolute position.
			-- (New position may be beyond physical length.)
		require
			file_opened: not is_closed
			non_negative_argument: abs_position >= 0

	move (offset: INTEGER)
			-- Advance by offset from current location.
		require
			file_opened: not is_closed

	next_line
			-- Move to next input line.
		require
			is_readable: file_readable

	recede (abs_position: INTEGER)
			-- Go to the absolute position backwards,
			-- starting from end of file.
		require
			file_opened: not is_closed
			non_negative_argument: abs_position >= 0

	search (v: like item)
			-- Move to first position (at or after current
			-- position) where item and v are equal.
			-- If structure does not include v ensure that
			-- exhausted will be true.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from BILINEAR)
		ensure -- from LINEAR
			object_found: (not exhausted and object_comparison) implies equal (v, item)
			item_found: (not exhausted and not object_comparison) implies v = item

	start
			-- Go to first position.
		require -- from  TRAVERSABLE
			True
		require else
			file_opened: not is_closed
	
feature -- Element change

	add_permission (who, what: STRING)
			-- Add read, write, execute or setuid permission
			-- for who ('u', 'g' or 'o') to what.
		require
			who_is_not_void: who /= void
			what_is_not_void: what /= void
			file_descriptor_exists: exists

	append (f: like Current)
			-- Append a copy of the contents of f.
		require -- from SEQUENCE
			argument_not_void: s /= void
		require else
			target_is_closed: is_closed
			source_is_closed: f.is_closed
		ensure -- from SEQUENCE
			new_count: count >= old count
		ensure then
			new_count: count = old count + f.count
			files_closed: f.is_closed and is_closed

	basic_store (object: ANY)
			-- Produce an external representation of the
			-- entire object structure reachable from object.
			-- Retrievable within current system only.
		require -- from IO_MEDIUM
			object_not_void: object /= void
			exists: exists
			is_open_write: is_open_write
			support_storable: support_storable

	change_date: INTEGER
			-- Time stamp of last change.
		require
			file_exists: exists

	change_group (new_group_id: INTEGER)
			-- Change group of file to new_group_id found in
			-- system password file.
		require
			file_exists: exists

	change_mode (mask: INTEGER)
			-- Replace mode by mask.
		require
			file_exists: exists

	change_name (new_name: STRING)
			-- Change file name to new_name
		require
			new_name_not_void: new_name /= void
			file_exists: exists
		ensure
			name_changed: name.is_equal (new_name)

	change_owner (new_owner_id: INTEGER)
			-- Change owner of file to new_owner_id found in
			-- system password file. On some systems this
			-- requires super-user privileges.
		require
			file_exists: exists

	extend (v: CHARACTER)
			-- Include v at end.
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from BAG
			one_more_occurrence: occurrences (v) = old (occurrences (v)) + 1

	fill (other: CONTAINER [CHARACTER])
			-- Fill with as many items of other as possible.
			-- The representations of other and current structure
			-- need not be the same.
			-- (from COLLECTION)
		require -- from COLLECTION
			other_not_void: other /= void
			extendible

	flush
			-- Flush buffered data to disk.
			-- Note that there is no guarantee that the operating
			-- system will physically write the data to the disk.
			-- At least it will end up in the buffer cache,
			-- making the data visible to other processes.
		require
			is_open: not is_closed

	force (v: like item)
			-- Add v to end.
			-- (from SEQUENCE)
		require -- from SEQUENCE
			extendible: extendible
		ensure then -- from SEQUENCE
			new_count: count = old count + 1
			item_inserted: has (v)

	general_store (object: ANY)
			-- Produce an external representation of the
			-- entire object structure reachable from object.
			-- Retrievable from other systems for same platform
			-- (machine architecture).
		require -- from IO_MEDIUM
			object_not_void: object /= void
			exists: exists
			is_open_write: is_open_write
			support_storable: support_storable

	independent_store (object: ANY)
			-- Produce an external representation of the
			-- entire object structure reachable from object.
			-- Retrievable from other systems for the same or other
			-- platform (machine architecture).
		require -- from IO_MEDIUM
			object_not_void: object /= void
			exists: exists
			is_open_write: is_open_write
			support_storable: support_storable

	link (fn: STRING)
			-- Link current file to fn.
			-- fn must not already exist.
		require
			file_exists: exists

	new_line
			-- Write a new line character at current position.
			-- Was declared in FILE as synonym of put_new_line.
		require -- from IO_MEDIUM
			extendible: extendible

	put (v: like item)
			-- Add v to end.
			-- (from SEQUENCE)
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from SEQUENCE
			new_count: count = old count + 1

	put_boolean (b: BOOLEAN)
			-- Write b at current position.
			-- Was declared in FILE as synonym of putbool.
		require -- from IO_MEDIUM
			extendible: extendible

	put_character (c: CHARACTER)
			-- Write c at current position.
			-- Was declared in FILE as synonym of putchar.
		require -- from IO_MEDIUM
			extendible: extendible

	put_double (d: DOUBLE)
			-- Write d at current position.
			-- Was declared in FILE as synonym of putdouble.
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer (i: INTEGER)
			-- Write i at current position.
			-- Was declared in FILE as synonym of putint.
		require -- from IO_MEDIUM
			extendible: extendible

	put_new_line
			-- Write a new line character at current position.
			-- Was declared in FILE as synonym of new_line.
		require -- from IO_MEDIUM
			extendible: extendible

	put_real (r: REAL)
			-- Write r at current position.
			-- Was declared in FILE as synonym of putreal.
		require -- from IO_MEDIUM
			extendible: extendible

	put_string (s: STRING)
			-- Write s at current position.
			-- Was declared in FILE as synonym of putstring.
		require -- from IO_MEDIUM
			extendible: extendible
			non_void: s /= void

	putbool (b: BOOLEAN)
			-- Write b at current position.
			-- Was declared in FILE as synonym of put_boolean.
		require -- from IO_MEDIUM
			extendible: extendible

	putchar (c: CHARACTER)
			-- Write c at current position.
			-- Was declared in FILE as synonym of put_character.
		require -- from IO_MEDIUM
			extendible: extendible

	putdouble (d: DOUBLE)
			-- Write d at current position.
			-- Was declared in FILE as synonym of put_double.
		require -- from IO_MEDIUM
			extendible: extendible

	putint (i: INTEGER)
			-- Write i at current position.
			-- Was declared in FILE as synonym of put_integer.
		require -- from IO_MEDIUM
			extendible: extendible

	putreal (r: REAL)
			-- Write r at current position.
			-- Was declared in FILE as synonym of put_real.
		require -- from IO_MEDIUM
			extendible: extendible

	putstring (s: STRING)
			-- Write s at current position.
			-- Was declared in FILE as synonym of put_string.
		require -- from IO_MEDIUM
			extendible: extendible
			non_void: s /= void

	remove_permission (who, what: STRING)
			-- Remove read, write, execute or setuid permission
			-- for who ('u', 'g' or 'o') to what.
		require
			who_is_not_void: who /= void
			what_is_not_void: what /= void
			file_descriptor_exists: exists

	set_access (time: INTEGER)
			-- Stamp with time (access only).
		require
			file_exists: exists
		ensure
			acess_date_updated: access_date = time
			date_unchanged: date = old date

	set_date (time: INTEGER)
			-- Stamp with time (modification time only).
		require
			file_exists: exists
		ensure
			access_date_unchanged: access_date = old access_date
			date_updated: date = time

	stamp (time: INTEGER)
			-- Stamp with time (for both access and modification).
		require
			file_exists: exists
		ensure
			date_updated: date = time

	touch
			-- Update time stamp (for both access and modification).
		require
			file_exists: exists
		ensure
			date_changed: date /= old date
	
feature -- Removal

	delete
			-- Remove link with physical file.
			-- File does not physically disappear from the disk
			-- until no more processes reference it.
			-- I/O operations on it are still possible.
			-- A directory must be empty to be deleted.
		require
			exists: exists

	dispose
			-- Ensure this medium is closed when garbage collected.
			-- (from IO_MEDIUM)

	prune_all (v: like item)
			-- Remove all occurrences of v; go off.
			-- (from SEQUENCE)
		require -- from COLLECTION
			prunable
		ensure -- from COLLECTION
			no_more_occurrences: not has (v)

	reset (fn: STRING)
			-- Change file name to fn and reset
			-- file descriptor and all information.
		require
			valid_file_name: fn /= void
		ensure
			file_renamed: name = fn
			file_closed: is_closed

	wipe_out
			-- Remove all items.
		require -- from COLLECTION
			prunable
		require else
			is_closed: is_closed
		ensure -- from COLLECTION
			wiped_out: is_empty
	
feature -- Conversion

	linear_representation: LINEAR [CHARACTER]
			-- Representation as a linear structure
			-- (from LINEAR)
	
feature -- Obsolete

	lastchar: CHARACTER
			-- Last character read by read_character
			-- (from IO_MEDIUM)

	lastdouble: DOUBLE
			-- Last double read by read_double
			-- (from IO_MEDIUM)

	lastint: INTEGER
			-- Last integer read by read_integer
			-- (from IO_MEDIUM)

	lastreal: REAL
			-- Last real read by read_real
			-- (from IO_MEDIUM)

	laststring: STRING
			-- Last string read
			-- (from IO_MEDIUM)
	
feature -- Convenience

	copy_to (file: like Current)
			-- Copy content of current from current cursor
			-- position to end of file into file from
			-- current cursor position of file.
		require
			file_not_void: file /= void
			file_is_open_write: file.is_open_write
			current_is_open_read: is_open_read
	
feature -- Input

	read_character
			-- Read a new character.
			-- Make result available in last_character.
			-- Was declared in FILE as synonym of readchar.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_double
			-- Read a new double.
			-- Make result available in last_double.
			-- Was declared in FILE as synonym of readdouble.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_integer
			-- Read a new integer.
			-- Make result available in last_integer.
			-- Was declared in FILE as synonym of readint.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_line
			-- Read a string until new line or end of file.
			-- Make result available in last_string.
			-- New line will be consumed but not part of last_string.
			-- Was declared in FILE as synonym of readline.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_real
			-- Read a new real.
			-- Make result available in last_real.
			-- Was declared in FILE as synonym of readreal.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_stream (nb_char: INTEGER)
			-- Read a string of at most nb_char bound characters
			-- or until end of file.
			-- Make result available in last_string.
			-- Was declared in FILE as synonym of readstream.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	read_word
			-- Read a string, excluding white space and stripping
			-- leading white space.
			-- Make result available in last_string.
			-- White space characters are: blank, new_line, tab,
			-- vertical tab, formfeed, end of file.
			-- Was declared in FILE as synonym of readword.
		require
			is_readable: file_readable

	readchar
			-- Read a new character.
			-- Make result available in last_character.
			-- Was declared in FILE as synonym of read_character.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readdouble
			-- Read a new double.
			-- Make result available in last_double.
			-- Was declared in FILE as synonym of read_double.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readint
			-- Read a new integer.
			-- Make result available in last_integer.
			-- Was declared in FILE as synonym of read_integer.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readline
			-- Read a string until new line or end of file.
			-- Make result available in last_string.
			-- New line will be consumed but not part of last_string.
			-- Was declared in FILE as synonym of read_line.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readreal
			-- Read a new real.
			-- Make result available in last_real.
			-- Was declared in FILE as synonym of read_real.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readstream (nb_char: INTEGER)
			-- Read a string of at most nb_char bound characters
			-- or until end of file.
			-- Make result available in last_string.
			-- Was declared in FILE as synonym of read_stream.
		require -- from IO_MEDIUM
			is_readable: readable
		require else
			is_readable: file_readable

	readword
			-- Read a string, excluding white space and stripping
			-- leading white space.
			-- Make result available in last_string.
			-- White space characters are: blank, new_line, tab,
			-- vertical tab, formfeed, end of file.
			-- Was declared in FILE as synonym of read_word.
		require
			is_readable: file_readable
	
feature -- Iteration

	do_all (action: PROCEDURE [ANY, TUPLE [CHARACTER]])
			-- Apply action to every item.
			-- Semantics not guaranteed if action changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			action_exists: action /= void

	do_if (action: PROCEDURE [ANY, TUPLE [CHARACTER]]; test: FUNCTION [ANY, TUPLE [CHARACTER], BOOLEAN])
			-- Apply action to every item that satisfies test.
			-- Semantics not guaranteed if action or test changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from LINEAR)
		require -- from TRAVERSABLE
			action_exists: action /= void
			test_exits: test /= void

	for_all (test: FUNCTION [ANY, TUPLE [CHARACTER], BOOLEAN]): BOOLEAN
			-- Is test true for all items?
			-- (from LINEAR)
		require -- from TRAVERSABLE
			test_exits: test /= void

	there_exists (test: FUNCTION [ANY, TUPLE [CHARACTER], BOOLEAN]): BOOLEAN
			-- Is test true for at least one item?
			-- (from LINEAR)
		require -- from TRAVERSABLE
			test_exits: test /= void
	
invariant

	valid_mode: closed_file <= mode and mode <= append_read_file
	name_exists: name /= void
	name_not_empty: not name.is_empty
		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)
		-- from FINITE
	empty_definition: is_empty = (count = 0)
	non_negative_count: count >= 0
		-- from ACTIVE
	writable_constraint: writable implies readable
	empty_constraint: is_empty implies (not readable) and (not writable)
		-- from BILINEAR
	not_both: not (after and before)
	before_constraint: before implies off
		-- from LINEAR
	after_constraint: after implies off
		-- from TRAVERSABLE
	empty_constraint: is_empty implies off

indexing
	library: "[
			EiffelBase: Library of reusable components for Eiffel.
	]"
	status: "[
			Copyright 1986-2001 Interactive Software Engineering (ISE).
			For ISE customers the original versions are an ISE product
			covered by the ISE Eiffel license and support agreements.
	]"
	license: "[
			EiffelBase may now be used by anyone as FREE SOFTWARE to
			develop any product, public-domain or commercial, without
			payment to ISE, under the terms of the ISE Free Eiffel Library
			License (IFELL) at http://eiffel.com/products/base/license.html.
	]"
	source: "[
			Interactive Software Engineering Inc.
			ISE Building
			360 Storke Road, Goleta, CA 93117 USA
			Telephone 805-685-1006, Fax 805-685-6869
			Electronic mail <info@eiffel.com>
			Customer support http://support.eiffel.com
	]"
	info: "[
			For latest info see award-winning pages: http://eiffel.com
	]"

end -- class FILE