note
	description: "Utility functions for the profiling application"
	author: "Comerge AG, DR"
	date: "$Date$"
	revision: "$Revision$"

class
	PROFILING_UTILS

inherit
	DT_SHARED_SYSTEM_CLOCK

feature -- Utility

	compute_mean (a_values: ARRAY[INTEGER_64]): REAL_64 is
			-- compute the mean of the values in the list
		require
			valid_input: a_values /= Void and then not a_values.is_empty
		local
			i: INTEGER
			sum: INTEGER_64
		do
			sum := 0
			from
				i := 1
			until
				i > a_values.count
			loop
				sum := sum + a_values.item (i)
				i := i + 1
			end

			Result := sum / a_values.count.to_real
		end

	compute_timestamp_now: INTEGER_64 is
			-- fancy routine to compute a timestamp in miliseconds precision
			-- (this is different to the regular unix timestamp which is measured in seconds)
		local
--			seconds: NATURAL_32
			microseconds: NATURAL_32
			tmp_sec: INTEGER
--			total_microseconds: NATURAL_64
		do
			current_seconds_and_microseconds($tmp_sec, $microseconds)
--				-- normalize
--			total_microseconds := tmp_sec.as_natural_64 * 1000000 + microseconds

--				-- convert to miliseconds
--			Result := (total_microseconds / 1000.0).truncated_to_integer_64

				-- normalize
			Result := (tmp_sec.as_integer_64 * 1000) + (microseconds / 1000.0).truncated_to_integer_64
		end

	print_list (a_list: DS_ARRAYED_LIST [ANY]) is
			-- mighty method to pretty print a list
		require
			valid_list: a_list /= Void
		local
			l_pretty: STRING
		do
			create l_pretty.make_empty

			from
				a_list.start
			until
				a_list.off
			loop
				l_pretty.append(a_list.item_for_iteration.out)
				l_pretty.append(", ")
				a_list.forth
			end

			l_pretty.remove_tail (2)
			print (l_pretty + "%N")
		end

	min_list (a_list: DS_ARRAYED_LIST [INTEGER_64]): INTEGER_64 is
			-- extracts the minimum value from the list
		local
			l_sorter: DS_QUICK_SORTER [INTEGER_64]
			l_comparator: KL_COMPARABLE_COMPARATOR [INTEGER_64]
			l_list: DS_ARRAYED_LIST [INTEGER_64]
		do
			create l_list.make_from_linear (a_list)
			create l_comparator.make
			create l_sorter.make (l_comparator)
			l_list.sort (l_sorter)
			Result := l_list.item (1)
		end

	remove_min (a_list: DS_ARRAYED_LIST [INTEGER_64]): INTEGER_64 is
			-- removes the smallest element in the list and returns the element
		local
			min_index, index: INTEGER
		do
			from
				min_index := 1
				index := 1
			until
				index > a_list.count
			loop
				if a_list.item (index) < a_list.item (min_index) then
					min_index := index
				end

				index := index + 1
			end

			a_list.remove (min_index)
			Result := a_list.item (min_index)
		end

	remove_max (a_list: DS_ARRAYED_LIST [INTEGER_64]): INTEGER_64 is
			-- Removes the largest element in the list and returns the element
		local
			max_index, index: INTEGER
		do
			from
				max_index := 1
				index := 1
			until
				index > a_list.count
			loop
				if a_list.item (index) > a_list.item (max_index) then
					max_index := index
				end

				index := index + 1
			end

			a_list.remove (max_index)
			Result := a_list.item (max_index)
		end

	max_list (a_list: DS_ARRAYED_LIST [INTEGER_64]): INTEGER_64 is
			-- extracts the maximum value from the list
		local
			l_sorter: DS_QUICK_SORTER [INTEGER_64]
			l_comparator: KL_COMPARABLE_COMPARATOR [INTEGER_64]
			l_list: DS_ARRAYED_LIST [INTEGER_64]
		do
			create l_list.make_from_linear (a_list)
			create l_comparator.make
			create l_sorter.make (l_comparator)
			l_list.sort (l_sorter)
			Result := l_list.last
		end

	create_message_payload(a_count: INTEGER): STRING is
			-- Creates the message payload with `a_count' characters
		do
			Result := random_string (a_count)
			if Result.count /= a_count then
				print ("ERROR: Length of the msg payload deviates from the specified length: " + Result.count.out + " instead of " + a_count.out)
			end
		end

feature -- Messaging


	serialize_timestamp_list (a_list: DS_ARRAYED_LIST [INTEGER_64]): DS_ARRAYED_LIST [A_STRING_VALUE] is
			-- converts the list of timestamps into the format used for the profiling results request reply message
			-- (we need this because INTEGER_64 is not supported by Aranea)
		require
			not_void: a_list /= Void
		do
			create Result.make (a_list.count)

			from
				a_list.start
			until
				a_list.off
			loop
				Result.force_last (a_list.item_for_iteration.out)
				a_list.forth
			end
		ensure
			same_size: a_list.count = Result.count
		end

	deserialize_timestamp_list (a_list: A_SEQUENCE_VALUE [A_STRING_VALUE]): DS_ARRAYED_LIST [INTEGER_64] is
			--  Deserialize timestamps retrieved from the profiling results request reply message
			-- (we need this because INTEGER_64 is not supported by Aranea)
		require
			not_void: a_list /= Void
		local
			l_list: DS_ARRAYED_LIST [A_STRING_VALUE]
		do
			l_list := a_list.sequence
			create Result.make (l_list.count)

			from
				l_list.start
			until
				l_list.off
			loop
				Result.force_last (l_list.item_for_iteration.value.to_integer_64)
				l_list.forth
			end
		ensure
			same_size: a_list.sequence.count = Result.count
		end

feature {NONE} -- Random

	char_z: CHARACTER is
			-- 'Z' character
		once
			Result := 'Z'
		end

	char_a: CHARACTER is
			-- 'A' character
		once
			Result := 'A'
		end

	dev_random_file: STRING is "/dev/urandom"

	modulo_range: INTEGER is
			-- The modulo divisor
		once
			Result := char_z.code - char_a.code + 1
		end

	to_alphabetic_character (a_character: CHARACTER): CHARACTER is
			-- Transform random character to character from the range A-Z.
		do
			Result := ((a_character.code \\ modulo_range) + char_a.code).to_character_8
		ensure
			result_in_range: Result.code >= char_a.code and Result.code <= char_z.code
		end

	random_string (a_string_length: INTEGER_32): STRING is
			-- Generate random string of length `a_string_length'.
			-- copied from CO_RANDOM_GENERATOR
		require
			length_ok: a_string_length > 0
		local
			file: PLAIN_TEXT_FILE
			i: INTEGER
			unfiltered_string: STRING
		do
				-- read from random device
			create file.make_open_read(dev_random_file)
			file.read_stream (a_string_length)
			file.close

				-- conversion to alphabetic string
			create unfiltered_string.make_from_string (file.last_string)
			create Result.make_empty

			from
				i := 1
			until
				i > a_string_length
			loop
				Result.append_character (to_alphabetic_character(unfiltered_string.item(i)))
				i := i + 1
			end

		ensure
			result_not_void: Result /= Void
			result_proper_len: Result.count = a_string_length
		end

feature {NONE} -- implementation

	current_seconds_and_microseconds(sec: TYPED_POINTER[INTEGER]; msec: TYPED_POINTER[NATURAL_32]) is
			-- Get the current time, starting at January 1, 1970.
		external
			"C inline use <sys/time.h>"
		alias
			"[
				{
					// C local variable
					struct timeval tp;
					gettimeofday(&tp, 0);
                   	*$sec = tp.tv_sec;
                   	*$msec = tp.tv_usec;	
				}
			]"
		end

--	compute_timestamp_now: INTEGER_64 is
--			-- compute a unix timestamp the eiffel way
--		local
--			l_now: DT_DATE_TIME
--			l_duration: DT_DATE_TIME_DURATION
--		do
--				-- make sure that we are using utc time everywhere
--			l_now := utc_system_clock.date_time_now
--			l_duration := l_now - unix_origin
--			l_duration := l_duration.to_canonical (unix_origin)
--			Result := l_duration.millisecond
--		end

--	unix_origin: DT_DATE_TIME is
--			-- base date for unix time stamps
--		once
--			create Result.make_precise (1970, 1, 1, 0, 0, 0, 0)
--		end


end