Railway Time: Basic time counter and utility functions

1 files changed, 132 insertions, 0 deletions

diff --git a/advtrains_line_automation/railwaytime.lua b/advtrains_line_automation/railwaytime.lua
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+++ b/advtrains_line_automation/railwaytime.lua
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+-- railwaytime.lua
+-- Advtrains uses a desynchronized time for train movement. Everything is counted relative to this time counter.
+-- The advtrains-internal time is in no way synchronized to the real-life time, due to:
+-- - Lag
+-- - Server stops/restarts
+-- However, this means that implementing a "timetable" system using the "real time" is not practical. Therefore,
+-- we introduce a custom time system, the RWT(Railway Time), which has nothing to do with RLT(Real-Life Time)
+-- RWT has a time cycle of 1 hour. This should be sufficient for most train lines that will ever be built in Minetest.
+-- A RWT looks like this:    37;25
+-- The ; is to distinguish it from a normal RLT (which has colons e.g. 12:34:56). Left number is minutes, right number is seconds.
+-- The minimum RWT is 00;00, the maximum is 59;59.
+-- It is OK to leave one places out at either end, esp. when writing relative times, such as:
+-- 43;3   22;0   2;30   0;10  ;10
+-- Those places are then filled with zeroes. Indeed, ";" would be valid for 00;00 .
+
+--[[
+1;23;45 = {
+	s=45,
+	m=23,
+	c=1, -- Cycle(~hour), not displayed most time
+}
+
+]]
+
+local rwt = {}
+
+--Time Stamp (Seconds since start of world)
+local e_time = 0
+
+-- Current rw time, cached and updated each step
+local crwtime
+
+function rwt.set_time(t)
+	e_time = t or 0
+end
+
+function rwt.get_time()
+	return e_time
+end
+
+function rwt.step(dt)
+	e_time = e_time + dt
+end
+
+function rwt.now()
+	return rwt.from_sec(e_time)
+end
+
+function rwt.new(c, m, s)
+	return {
+		c = c or 0,
+		m = m or 0,
+		s = s or 0
+	}
+end
+function rwt.copy(rwtime)
+	return {
+		c = rwtime.c or 0,
+		m = rwtime.m or 0,
+		s = rwtime.s or 0
+	}
+end
+
+function rwt.from_sec(stime)
+	local res = {}
+	local seconds = atfloor(stime)
+	res.s = seconds % 60
+	local minutes = atfloor(seconds/60)
+	res.m = minutes % 60
+	res.c = atfloor(minutes/60)
+	return res
+end
+
+function rwt.to_sec(rwtime, c_over)
+	return (c_over or rwtime.c)*60*60 + rwtime.m*60 + rwtime.s
+end
+
+function rwt.add(t1, t2)
+	local t1s = rwt.to_sec(t1)
+	local t2s = rwt.to_sec(t1)
+	return rwt.from_sec(t1s + t2s)
+end
+
+function rwt.sub(t1, t2)
+	local t1s = rwt.to_sec(t1)
+	local t2s = rwt.to_sec(t1)
+	return rwt.from_sec(t1s - t2s)
+end
+
+-- Threshold values
+-- "reftime" is the time to which this is made relative and defaults to now.
+rwt.CA_FUTURE	= 60*60 - 1		-- Selected so that time lies at or in the future of reftime (at nearest point in time)
+rwt.CA_FUTURES	= 60*60 		-- Same, except when times are equal, advances one full cycle
+rwt.CA_PAST		= 0				-- Selected so that time lies at or in the past of reftime
+rwt.CA_PASTS	= -1	 		-- Same, except when times are equal, goes back one full cycle
+rwt.CA_CENTER	= 30*60			-- If time is within past 30 minutes of reftime, selected as past, else selected as future.
+
+-- Adjusts the "cycle" value of a railway time to be in some relation to reftime.
+-- Modifies rwtime in-place
+function rwt.adjust(rwtime, reftime_p, thresh)
+	local reftime = reftime_p or rwt.now()
+	
+	local reftimes = rwt.to_sec(reftime)
+	
+	local rwtimes = rwt.to_sec(rwtime, 0)
+	local timeres = reftimes + thresh - rwtimes
+	local cycles = atfloor(timeres / (60*60))
+
+	rwtime.c = cycles
+end
+
+function rwt.get_adjust(rwtime, reftime, thresh)
+	local res = rwt.copy(rwtime)
+	rwt.adjust(res, reftime, thresh)
+	return res
+end
+
+function rwt.to_string(rwtime, places)
+	local pl = places or 2
+	if rwtime.c~=0 or pl>=3 then
+		return string.format("%d;%02d;%02d", rwtime.c, rwtime.m, rwtime.s)
+	elseif rwtime.m~=0 or pl>=2 then
+		return string.format("%02d;%02d", rwtime.m, rwtime.s)
+	else
+		return string.format(";%02d",rwtime.s)
+	end
+	return str
+end
+
+
+
+advtrains.lines.rwt = rwt