Changed the WGI_INPUT_STREAM and WGI_OUTPUT_STREAM interfaces

main changes for existing code  `read_stream' is renamed `read_string'

library/server/ewsgi/src/wgi_input_stream.e

@@ -11,21 +11,108 @@ note
 deferred class
 	WGI_INPUT_STREAM
 
+feature -- Input
+
+	read_character
+			-- Read the next character in input stream.
+			-- Make the result available in `last_character'.
+		require
+			is_open_read: is_open_read
+			not_end_of_input: not end_of_input
+		deferred
+		ensure
+			same_last_string_reference: last_string = old last_string
+		end
+
+	read_string (nb: INTEGER)
+		require
+			is_open_read: is_open_read
+			not_end_of_input: not end_of_input
+			nb_large_enough: nb > 0
+		deferred
+		ensure
+			last_string_count_small_enough: not end_of_input implies last_string.count <= nb
+			character_read: not end_of_input implies last_string.count > 0
+			same_last_string_reference: last_string = old last_string
+		end
+
+	read_to_string (a_string: STRING; pos, nb: INTEGER): INTEGER
+			-- Fill `a_string', starting at position `pos', with
+			-- at most `nb' characters read from input stream.
+			-- Return the number of characters actually read.
+			-- (Note that even if at least `nb' characters are available
+			-- in the input stream, there is no guarantee that they
+			-- will all be read.)
+		require
+			is_open_read: is_open_read
+			not_end_of_input: not end_of_input
+			a_string_not_void: a_string /= Void
+			valid_position: a_string.valid_index (pos)
+			nb_large_enough: nb > 0
+			nb_small_enough: nb <= a_string.count - pos + 1
+		local
+			i, end_pos: INTEGER
+		do
+			end_pos := pos + nb - 1
+			from
+				i := pos
+			until
+				i > end_pos
+			loop
+				read_character
+				if not end_of_input then
+					a_string.put (last_character, i)
+					i := i + 1
+				else
+					Result := i - pos - nb
+						-- Jump out of the loop.
+					i := end_pos + 1
+				end
+			end
+			Result := Result + i - pos
+		ensure
+			nb_char_read_large_enough: Result >= 0
+			nb_char_read_small_enough: Result <= nb
+			character_read: not end_of_input implies Result > 0
+			same_last_string_reference: last_string = old last_string
+		end
+
 feature -- Access
 
 	last_string: STRING_8
-			-- Last read string from stream
+			-- Last string read
+			-- (Note: this query always return the same object.
+			-- Therefore a clone should be used if the result
+			-- is to be kept beyond the next call to this feature.
+			-- However `last_string' is not shared between file objects.)
+		require
+			is_open_read: is_open_read
+			not_end_of_input: not end_of_input
+		deferred
+		ensure
+			last_string_not_void: Result /= Void
+		end
+
+	last_character: CHARACTER_8
+			-- Last item read
+		require
+			is_open_read: is_open_read
+			not_end_of_input: not end_of_input
 		deferred
 		end
 
-feature -- Basic operation
+feature -- Status report
 
-	read_stream (n: INTEGER)
-		require
-			n_positive: n > 0
+	is_open_read: BOOLEAN
+			-- Can items be read from input stream?
+		deferred
+		end
+
+	end_of_input: BOOLEAN
+			-- Has the end of input stream been reached?
+		require
+			is_open_read: is_open_read
 		deferred
-		ensure
-			at_max_n: last_string.count <= n
 		end
 
 note