indexing

	description: "Implementation of the STORABLE mechanism with streams."
	date: "$Date$"
	revision: "$Revision$"

class 
	STREAM

inherit
	IO_MEDIUM

create
	make,
	make_with_size

feature -- Initialization

	make is
			-- Create stream object with a default_size of 100 bytes
		do
			buffer_size := 200
			create_c_buffer
		end

	make_with_size (n: INTEGER) is
			-- Create stream object with a default_size of `n' bytes
		do
			buffer_size := n
			create_c_buffer
		end

feature -- Status report

	support_storable: BOOLEAN is True
			-- Can medium be used to store an Eiffel structure?

feature -- Access

	item: POINTER is
			-- Direct access to stored/retrieved data
		do
			Result := c_buffer (internal_buffer_access)
		end
	
	buffer: POINTER is
			-- C buffer correspond to the Eiffel STREAM
		obsolete
			"Use `item' instead to directly access stored/retrieved data"
		do
			Result := internal_buffer_access
		end

	buffer_size: INTEGER
			-- Buffer's size.

	object_stored_size: INTEGER
			-- Size of last stored object.

	create_c_buffer is
			-- Create the C memory corresponding to the C buffer.
		do
			internal_buffer_access := c_malloc (buffer_size)
		end

	retrieved: ANY is
			-- 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 else
			True
		local
			size: INTEGER
		do
			(create {MISMATCH_CORRECTOR}).mismatch_information.do_nothing
			Result := c_retrieved (internal_buffer_access, buffer_size, 0, $size)
			object_stored_size := size
		end

feature -- Element change

	basic_store (object: ANY) is
			-- Produce an external representation of the
			-- entire object structure reachable from `object'.
			-- Retrievable within current system only.
		local
			size: INTEGER
		do
			buffer_size := c_stream_basic_store (internal_buffer_access, buffer_size, $object, $size)
			object_stored_size := size
		end

	general_store (object: ANY) is
			-- Produce an external representation of the
			-- entire object structure reachable from `object'.
			-- Retrievable from other systems for same platform
			-- (machine architecture).
			--| This feature may use a visible name of a class written
			--| in the `visible' clause of the Ace file. This makes it
			--| possible to overcome class name clashes.
		local
			size: INTEGER
		do
			buffer_size := c_stream_general_store (internal_buffer_access, buffer_size, $object, $size)
			object_stored_size := size
		end

	independent_store (object: ANY) is
			-- Produce an external representation of the
			-- entire object structure reachable from `object'.
			-- Retrievable from other systems for the same or other
			-- platform (machine architecture).
		local
			size: INTEGER
		do
			buffer_size := c_stream_independent_store (internal_buffer_access, buffer_size, $object, $size)
			object_stored_size := size
		end

	set_additional_size (new_size: INTEGER) is
			-- Set `new_size' to BUFFER_SIZE, internal value used to
			-- increment `buffer_size' during storable operations.
		external
			"C | %"eif_store.h%""
		alias
			"set_buffer_size"
		end

feature {NONE} -- Implementation

	internal_buffer_access: POINTER
			-- Access to C buffer pointed by `item'.

	c_buffer (a_buf: POINTER): POINTER is
			-- Dereferenced pointer of `a_buf'
		require
			a_buf_not_null: a_buf /= default_pointer
		external
			"C inline"
		alias
			"*(EIF_POINTER *) $a_buf"
		end
			
	c_stream_basic_store (stream_buffer: POINTER; stream_buffer_size: INTEGER; object: POINTER; c_real_size: POINTER): INTEGER is
			-- Store object structure reachable form current object
			-- Return new size of `internal_buffer_access'.
		external
			"C signature (EIF_POINTER *, EIF_INTEGER, EIF_REFERENCE, EIF_INTEGER *): EIF_INTEGER use %"eif_store.h%""
		alias
			"stream_estore"
		end

	c_stream_general_store (stream_buffer: POINTER; stream_buffer_size: INTEGER; object: POINTER; c_real_size: POINTER): INTEGER is
			-- Store object structure reachable form current object
			-- Return new size of `internal_buffer_access'.
		external
			"C signature (EIF_POINTER *, EIF_INTEGER, EIF_REFERENCE, EIF_INTEGER *): EIF_INTEGER use %"eif_store.h%""
		alias
			"stream_eestore"
		end

	c_stream_independent_store (stream_buffer: POINTER; stream_buffer_size: INTEGER; object: POINTER; c_real_size: POINTER): INTEGER is
			-- Store object structure reachable form current object
			-- Return new size of `internal_buffer_access'.
		external
			"C signature (EIF_POINTER *, EIF_INTEGER, EIF_REFERENCE, EIF_INTEGER *): EIF_INTEGER use %"eif_store.h%""
		alias
			"stream_sstore"
		end

	c_retrieved (stream_buffer: POINTER; stream_buffer_size: INTEGER; stream_buffer_position: INTEGER; c_real_size: POINTER): ANY is
			-- Object structured retrieved from stream of pointer
			-- `stream_ptr'
		external
			"C signature (EIF_POINTER *, EIF_INTEGER, EIF_INTEGER, EIF_INTEGER *): EIF_REFERENCE use %"eif_retrieve.h%""
		alias
			"stream_eretrieve"	
		end
	
	c_malloc (size: INTEGER): POINTER is
		external
			"C | %"eif_store.h%""
		alias
			"stream_malloc"
		end

	c_free (buf: POINTER) is
		external
			"C signature (EIF_POINTER *) use %"eif_store.h%""
		alias
			"stream_free"
		end

feature -- Status report

	exists: BOOLEAN is True
			-- Stream exists in any cases.

	is_open_read: BOOLEAN is True
			-- Stream opens for input.

	is_open_write: BOOLEAN is True
			-- Stream opens for output.

	is_readable: BOOLEAN is True

	is_executable: BOOLEAN is
			-- Is stream executable?
		do
			Result := False
		end

	is_writable: BOOLEAN is True
			-- Stream is writable.

	readable: BOOLEAN is
			-- Is there a current item that may be read?
		do
		end

	extendible: BOOLEAN is
			-- May new items be added?
		do
			Result := True
		end

	is_closed: BOOLEAN
			-- Is the I/O medium open

feature -- Status setting

	close is
			-- Close medium.
		do
			is_closed := True
			c_free (internal_buffer_access)
			internal_buffer_access := default_pointer
		end

feature -- Output

	put_new_line, new_line is
			-- Write a new line character to medium
		require else
			stream_exists: exists
		do
			put_character ('%N')		
		end

	put_string, putstring (s: STRING) is
			-- Write `s' to medium.
		do
		end

	put_character, putchar (c: CHARACTER) is
			-- Write `c' to medium.
		do
		end

	put_real, putreal (r: REAL) is
			-- Write `r' to medium.
		do
		end

	put_integer, putint (i: INTEGER) is
			-- Write `i' to medium.
		do
		end

	put_boolean, putbool (b: BOOLEAN) is
			-- Write `b' to medium.
		do
		end

	put_double, putdouble (d: DOUBLE) is
			-- Write `d' to medium.
		do
		end

feature -- Input

	read_real, readreal is
			-- Read a new real.
			-- Make result available in `last_real'.
		do
		end

	read_double, readdouble is
			-- Read a new double.
			-- Make result available in `last_double'.
		do
		end

	read_character, readchar is
			-- Read a new character.
			-- Make result available in `last_character'.
		do
		end

	read_integer, readint is
			-- Read a new integer.
			-- Make result available in `last_integer'.
		do
		end

	read_stream, readstream (nb_char: INTEGER) is
			-- Read a string of at most `nb_char' bound characters
			-- or until end of medium is encountered.
			-- Make result available in `last_string'.
		do
		end

	read_line, readline is
			-- Read characters until a new line or
			-- end of medium.
			-- Make result available in `last_string'.
		do
		end

feature {NONE} -- Not exported

	name: STRING is
			-- Not meaningful
		do
		end

	handle: INTEGER is
			-- Handle to medium
		do
		end

	handle_available: BOOLEAN is
			-- Is the handle available after class has been
			-- created?
		do
		end

indexing

	library: "[
			EiffelBase: Library of reusable components for Eiffel.
			]"

	status: "[
--| Copyright (c) 1993-2006 University of Southern California and contributors.
			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 STREAM