indexing
	description: "Encapsulation of standard implementation of IStream interface."
	status: "See notice at end of class"
	date: "$Date$"
	revision: "$Revision$"

class interface
	ECOM_STREAM

create 

	make_from_other (other: ECOM_INTERFACE)
			-- Make from other Queriable.
			-- (from ECOM_QUERIABLE)
		require -- from ECOM_QUERIABLE
			non_void_other: other /= void
		ensure -- from ECOM_QUERIABLE
			valid_initializer: initializer /= default_pointer
			exists: exists

	make_from_pointer (cpp_obj: POINTER)
			-- Make from pointer
		require -- from ECOM_QUERIABLE
			non_default_pointer: a_pointer /= default_pointer
		ensure -- from ECOM_QUERIABLE
			valid_initializer: initializer /= default_pointer
			exists: exists

feature --  Access

	hresult: INTEGER
			-- Original HRESULT.
			-- (from ECOM_EXCEPTION)
		require -- from ECOM_EXCEPTION
			applicable: is_developer_exception

	hresult_code: INTEGER
			-- Status code.
			-- (from ECOM_EXCEPTION)
		require -- from ECOM_EXCEPTION
			applicable: is_developer_exception

	hresult_facility: INTEGER
			-- Facility code.
			-- (from ECOM_EXCEPTION)
		require -- from ECOM_EXCEPTION
			applicable: is_developer_exception

	hresult_message: STRING
			-- Error message.
			-- (from ECOM_EXCEPTION)
		require -- from ECOM_EXCEPTION
			applicable: is_developer_exception
		ensure -- from ECOM_EXCEPTION
			non_void_message: Result /= void
	
feature -- Access

	access_time: WEL_FILE_TIME
			-- Access time

	Check_instruction: INTEGER is 7
			-- Exception code for violated check
			-- (from EXCEP_CONST)

	Class_invariant: INTEGER is 6
			-- Exception code for violated class invariant
			-- (from EXCEP_CONST)

	Com_exception: INTEGER is 28
			-- Exception code for a COM error.
			-- (from EXCEP_CONST)

	creation_time: WEL_FILE_TIME
			-- Creation time

	description (stat_flag: INTEGER): ECOM_STATSTG
			-- STATSTG structure
			-- See class ECOM_STAT_FLAGS for stat_flag values.
		require
			valid_stat_flag: is_valid_stat_flag (stat_flag)
		ensure
			Result /= void

	Developer_exception: INTEGER is 24
			-- Exception code for developer exception
			-- (from EXCEP_CONST)

	end_of_stream: BOOLEAN
			-- Is current seek pointer at end of stream?
			-- Valid only after read ,update_end_of_stream, start, or finish.

	exists: BOOLEAN
			-- Is wrapped structure initialized?
			-- (from ECOM_QUERIABLE)

	External_exception: INTEGER is 18
			-- Exception code for operating system error
			-- which does not set the errno variable
			-- (Unix-specific)
			-- (from EXCEP_CONST)

	Floating_point_exception: INTEGER is 5
			-- Exception code for floating point exception
			-- (from EXCEP_CONST)

	Incorrect_inspect_value: INTEGER is 9
			-- Exception code for inspect value which is not one
			-- of the inspect constants, if there is no Else_part
			-- (from EXCEP_CONST)

	Io_exception: INTEGER is 21
			-- Exception code for I/O error
			-- (from EXCEP_CONST)

	is_valid_lock (lock: INTEGER): BOOLEAN
			-- Is lock a valid locktype?
			-- (from ECOM_LOCK_TYPES)

	is_valid_seek (seek: INTEGER): BOOLEAN
			-- Is seek a valid IStorage and IStream seek flag?
			-- (from ECOM_STREAM_SEEK)

	is_valid_stat_flag (flag: INTEGER): BOOLEAN
			-- Is flag a valid stat flag?
			-- (from ECOM_STAT_FLAGS)

	item: POINTER
			-- Pointer to COM object wrapper.
			-- (from ECOM_QUERIABLE)

	last_boolean: BOOLEAN
			-- last read BOOLEAN

	last_character: CHARACTER
			-- last read CHARACTER

	last_integer: INTEGER
			-- last read INTEGER

	last_real: REAL
			-- last read REAL

	last_string: STRING
			-- last read STRING

	lock_exclusive: INTEGER
			-- Attempts to read or write this stream by other stream openings
			-- return error EOLE_STG_E_ACCESSDENIED.
			-- (from ECOM_LOCK_TYPES)

	lock_onlyonce: INTEGER
			-- If lock is granted, no other EOLE_LOCK_ONLYONCE lock can be
			-- obtained on bytes in given region. Usually this lock type
			-- is an alias for some other lock type and other semantics might occur
			-- as a side effect.
			-- (from ECOM_LOCK_TYPES)

	lock_write: INTEGER
			-- If lock is granted, specified region of stream
			-- can be read by calling IStream.Read from any opening of
			-- this stream. Attempts to write to this region from any opening
			-- of this stream other than the one to which lock was granted
			-- returns error EOLE_STG_E_ACCESSDENIED.
			-- (from ECOM_LOCK_TYPES)

	locks_supported: INTEGER
			-- Types of region locking supported by stream

	Loop_invariant: INTEGER is 11
			-- Exception code for violated loop invariant
			-- (from EXCEP_CONST)

	Loop_variant: INTEGER is 10
			-- Exception code for non-decreased loop variant
			-- (from EXCEP_CONST)

	modification_time: WEL_FILE_TIME
			-- Modification time

	name: STRING
			-- Name

	No_more_memory: INTEGER is 2
			-- Exception code for failed memory allocation
			-- (from EXCEP_CONST)

	Operating_system_exception: INTEGER is 22
			-- Exception code for operating system error
			-- which sets the errno variable
			-- (Unix-specific)
			-- (from EXCEP_CONST)

	Postcondition: INTEGER is 4
			-- Exception code for violated postcondition
			-- (from EXCEP_CONST)

	Precondition: INTEGER is 3
			-- Exception code for violated precondition
			-- (from EXCEP_CONST)

	Rescue_exception: INTEGER is 14
			-- Exception code for exception in rescue clause
			-- (from EXCEP_CONST)

	Retrieve_exception: INTEGER is 23
			-- Exception code for retrieval error
			-- may be raised by retrieved in IO_MEDIUM.
			-- (from EXCEP_CONST)

	Routine_failure: INTEGER is 8
			-- Exception code for failed routine
			-- (from EXCEP_CONST)

	Runtime_io_exception: INTEGER is 27
			-- Exception code for I/O error raised by runtime functions
			-- such as store/retrieve, file access...
			-- (from EXCEP_CONST)

	Signal_exception: INTEGER is 12
			-- Exception code for operating system signal
			-- (from EXCEP_CONST)

	size: ECOM_ULARGE_INTEGER
			-- Size in bytes

	statflag_default: INTEGER
			-- Indicate that this is not used for property
			-- (from ECOM_STAT_FLAGS)

	statflag_noname: INTEGER
			-- Indicate that this is not used for property
			-- (from ECOM_STAT_FLAGS)

	stream_seek_cur: INTEGER
			-- Sets seek position relative to
			-- current position of stream
			-- (from ECOM_STREAM_SEEK)

	stream_seek_end: INTEGER
			-- Sets seek position relative to
			-- current end of stream
			-- (from ECOM_STREAM_SEEK)

	stream_seek_set: INTEGER
			-- Sets seek position relative to
			-- beginning of stream
			-- (from ECOM_STREAM_SEEK)

	Void_assigned_to_expanded: INTEGER is 19
			-- Exception code for assignment of void value
			-- to expanded entity
			-- (from EXCEP_CONST)

	Void_call_target: INTEGER is 1
			-- Exception code for feature applied to void reference
			-- (from EXCEP_CONST)
	
feature -- Status report

	assertion_violation: BOOLEAN
			-- Is last exception originally due to a violated
			-- assertion or non-decreasing variant?
			-- (from EXCEPTIONS)

	class_name: STRING
			-- Name of the class that includes the recipient
			-- of original form of last exception
			-- (from EXCEPTIONS)

	developer_exception_name: STRING
			-- Name of last developer-raised exception
			-- (from EXCEPTIONS)
		require -- from EXCEPTIONS
			applicable: is_developer_exception

	exception: INTEGER
			-- Code of last exception that occurred
			-- (from EXCEPTIONS)

	exception_trace: STRING
			-- String representation of the exception trace
			-- (from EXCEPTIONS)

	is_developer_exception: BOOLEAN
			-- Is the last exception originally due to
			-- a developer exception?
			-- (from EXCEPTIONS)

	is_developer_exception_of_name (name: STRING): BOOLEAN
			-- Is the last exception originally due to a developer
			-- exception of name name?
			-- (from EXCEPTIONS)

	is_signal: BOOLEAN
			-- Is last exception originally due to an external
			-- event (operating system signal)?
			-- (from EXCEPTIONS)

	is_system_exception: BOOLEAN
			-- Is last exception originally due to an
			-- external event (operating system error)?
			-- (from EXCEPTIONS)

	meaning (except: INTEGER): STRING
			-- A message in English describing what except is
			-- (from EXCEPTIONS)

	original_class_name: STRING
			-- Name of the class that includes the recipient
			-- of original form of last exception
			-- (from EXCEPTIONS)

	original_exception: INTEGER
			-- Original code of last exception that triggered
			-- current exception
			-- (from EXCEPTIONS)

	original_recipient_name: STRING
			-- Name of the routine whose execution was
			-- interrupted by original form of last exception
			-- (from EXCEPTIONS)

	original_tag_name: STRING
			-- Assertion tag for original form of last
			-- assertion violation.
			-- (from EXCEPTIONS)

	recipient_name: STRING
			-- Name of the routine whose execution was
			-- interrupted by last exception
			-- (from EXCEPTIONS)

	tag_name: STRING
			-- Tag of last violated assertion clause
			-- (from EXCEPTIONS)
	
feature -- Status setting

	catch (code: INTEGER)
			-- Make sure that any exception of code code will be
			-- caught. This is the default.
			-- (from EXCEPTIONS)

	die (code: INTEGER)
			-- Terminate execution with exit status code,
			-- without triggering an exception.
			-- (from EXCEPTIONS)

	ignore (code: INTEGER)
			-- Make sure that any exception of code code will be
			-- ignored. This is not the default.
			-- (from EXCEPTIONS)

	message_on_failure
			-- Print an exception history table
			-- in case of failure.
			-- This is the default.
			-- (from EXCEPTIONS)

	no_message_on_failure
			-- Do not print an exception history table
			-- in case of failure.
			-- (from EXCEPTIONS)

	raise (name: STRING)
			-- Raise a developer exception of name name.
			-- (from EXCEPTIONS)
	
feature -- Basic Operations

	clone_stream: ECOM_STREAM
			-- New stream referencing
			-- the same bytes as Current
			-- Seek pointer is also cloned
		ensure
			clone_created: Result /= void and then Result.exists

	copy_to (destination: ECOM_STREAM; bytes: ECOM_ULARGE_INTEGER)
			-- Copy bytes number of bytes from current seek pointer
			-- in stream to current seek pointer in
			-- destination.
		require
			valid_destination: destination /= void and then destination.exists
			valid_bytes_number: bytes /= void and then bytes.exists

	finish
			-- Set seek pointer to end of stream.
		ensure
			at_end: end_of_stream

	lock_region (offset, count: ECOM_ULARGE_INTEGER; lock: INTEGER)
			-- Restricts access to range of bytes defined by
			-- offset and count.
		require
			valid_offset: offset /= void and then offset.exists
			valid_count: count /= void and then count.exists
			valid_lock: is_valid_lock (lock)

	read (buffer: POINTER; bytes: INTEGER)
			-- Reads bytes number of bytes from stream
			-- into buffer starting at current seek pointer.
		require
			valid_buffer: buffer /= default_pointer
			valid_bytes: bytes >= 0

	read_boolean
			-- Read boolean from stream.

	read_character
			-- Read character from stream.

	read_integer
			-- Read integer from stream.

	read_real
			-- Read real from stream.

	read_string
			-- Read string from stream.

	seek (displacement: ECOM_LARGE_INTEGER; origin: INTEGER)
			-- Move seek pointer by displacement
			-- relative to origin.
			-- See class ECOM_STREAM_SEEK for origin values.
		require
			non_void_displacement: displacement /= void
			valid_displacement: displacement.exists
			valid_seek_origin: is_valid_seek (origin)

	set_size (new_size: ECOM_ULARGE_INTEGER)
			-- Change size of stream to new_size.
		require
			valid_new_size: new_size /= void and then new_size.exists
		ensure
			size = new_size

	start
			-- Set seek pointer to beginning of stream.
		ensure
			not_end: not end_of_stream

	unlock_region (offset, count: ECOM_ULARGE_INTEGER; lock: INTEGER)
			-- Removes access restriction to range of bytes defined by
			-- offset and count.
		require
			valid_offset: offset /= void and then offset.exists
			valid_count: count /= void and then count.exists
			valid_lock: is_valid_lock (lock)

	update_end_of_stream
			-- Update value of end_of_stream.

	write (buffer: POINTER; bytes: INTEGER)
			-- Writes bytes number of bytes into stream
			-- starting at current seek pointer.
		require
			valid_buffer: buffer /= default_pointer

	write_boolean (boolean: BOOLEAN)
			-- Write boolean into stream.

	write_character (character: CHARACTER)
			-- Write character into stream.

	write_integer (integer: INTEGER)
			-- Write integer into stream.

	write_real (real: REAL)
			-- Write real into stream.

	write_string (string: STRING)
			-- Write string into stream.
		require
			string /= void
	
feature -- Element Change

	trigger (code: INTEGER)
			-- Raise exception with code code.
			-- See class ECOM_EXCEPTION_CODES for possible values.
			-- (from ECOM_EXCEPTION)
	
invariant

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)
		-- from ECOM_QUERIABLE
	queriable_invariant: initializer /= default_pointer and then exists

end -- class ECOM_STREAM