Remove last files with CR-LF line endings.

1 files changed, 447 insertions, 447 deletions

diff --git a/advtrains/helpers.lua b/advtrains/helpers.lua
index 65f25ba..3b0bedd 100644
--- a/advtrains/helpers.lua
+++ b/advtrains/helpers.lua
@@ -1,447 +1,447 @@
---advtrains by orwell96, see readme.txt

-

-local dir_trans_tbl={

-	[0]={x=0, z=1, y=0},

-	[1]={x=1, z=2, y=0},

-	[2]={x=1, z=1, y=0},

-	[3]={x=2, z=1, y=0},

-	[4]={x=1, z=0, y=0},

-	[5]={x=2, z=-1, y=0},

-	[6]={x=1, z=-1, y=0},

-	[7]={x=1, z=-2, y=0},

-	[8]={x=0, z=-1, y=0},

-	[9]={x=-1, z=-2, y=0},

-	[10]={x=-1, z=-1, y=0},

-	[11]={x=-2, z=-1, y=0},

-	[12]={x=-1, z=0, y=0},

-	[13]={x=-2, z=1, y=0},

-	[14]={x=-1, z=1, y=0},

-	[15]={x=-1, z=2, y=0},

-}

-

-local dir_angle_tbl={}

-for d,v in pairs(dir_trans_tbl) do

-	local uvec = vector.normalize(v)

-	dir_angle_tbl[d] = math.atan2(-uvec.x, uvec.z)

-end

-

-

-function advtrains.dir_to_angle(dir)

-	return dir_angle_tbl[dir] or error("advtrains: in helpers.lua/dir_to_angle() given dir="..(dir or "nil"))

-end

-

-function advtrains.dirCoordSet(coord, dir)

-	return vector.add(coord, advtrains.dirToCoord(dir))

-end

-advtrains.pos_add_dir = advtrains.dirCoordSet

-

-function advtrains.pos_add_angle(pos, ang)

-	-- 0 is +Z -> meaning of sin/cos swapped

-	return vector.add(pos, {x = -math.sin(ang), y = 0, z = math.cos(ang)})

-end

-

-function advtrains.dirToCoord(dir)

-	return dir_trans_tbl[dir] or error("advtrains: in helpers.lua/dir_to_vector() given dir="..(dir or "nil"))

-end

-advtrains.dir_to_vector = advtrains.dirToCoord

-

-function advtrains.maxN(list, expectstart)

-	local n=expectstart or 0

-	while list[n] do

-		n=n+1

-	end

-	return n-1

-end

-

-function advtrains.minN(list, expectstart)

-	local n=expectstart or 0

-	while list[n] do

-		n=n-1

-	end

-	return n+1

-end

-

-function atround(number)

-	return math.floor(number+0.5)

-end

-atfloor = math.floor

-

-

-function advtrains.round_vector_floor_y(vec)

-	return {x=math.floor(vec.x+0.5), y=math.floor(vec.y), z=math.floor(vec.z+0.5)}

-end

-

-function advtrains.yawToDirection(yaw, conn1, conn2)

-	if not conn1 or not conn2 then

-		error("given nil to yawToDirection: conn1="..(conn1 or "nil").." conn2="..(conn1 or "nil"))

-	end

-	local yaw1 = advtrains.dir_to_angle(conn1)

-	local yaw2 = advtrains.dir_to_angle(conn2)

-	local adiff1 = advtrains.minAngleDiffRad(yaw, yaw1)

-	local adiff2 = advtrains.minAngleDiffRad(yaw, yaw2)

-	

-	if math.abs(adiff2)<math.abs(adiff1) then

-		return conn2

-	else

-		return conn1

-	end

-end

-

-function advtrains.yawToAnyDir(yaw)

-	local min_conn, min_diff=0, 10

-	for conn, vec in pairs(advtrains.dir_trans_tbl) do

-		local yaw1 = advtrains.dir_to_angle(conn)

-		local diff = math.abs(advtrains.minAngleDiffRad(yaw, yaw1))

-		if diff < min_diff then

-			min_conn = conn

-			min_diff = diff

-		end

-	end

-	return min_conn

-end

-function advtrains.yawToClosestConn(yaw, conns)

-	local min_connid, min_diff=1, 10

-	for connid, conn in ipairs(conns) do

-		local yaw1 = advtrains.dir_to_angle(conn.c)

-		local diff = math.abs(advtrains.minAngleDiffRad(yaw, yaw1))

-		if diff < min_diff then

-			min_connid = connid

-			min_diff = diff

-		end

-	end

-	return min_connid

-end

-

-local pi, pi2 = math.pi, 2*math.pi

-function advtrains.minAngleDiffRad(r1, r2)

-	while r1>pi2 do

-		r1=r1-pi2

-	end

-	while r1<0 do

-		r1=r1+pi2

-	end

-	while r2>pi2 do

-		r2=r2-pi2

-	end

-	while r1<0 do

-		r2=r2+pi2

-	end

-	local try1=r2-r1

-	local try2=r2+pi2-r1

-	local try3=r2-pi2-r1

-	

-	local minabs = math.min(math.abs(try1), math.abs(try2), math.abs(try3))

-	if minabs==math.abs(try1) then

-		return try1

-	end

-	if minabs==math.abs(try2) then

-		return try2

-	end

-	if minabs==math.abs(try3) then

-		return try3

-	end

-end

-

-

--- Takes 2 connections (0...AT_CMAX) as argument

--- Returns the angle median of those 2 positions from the pov

--- of standing on the cdir1 side and looking towards cdir2

--- cdir1 - >NODE> - cdir2

-function advtrains.conn_angle_median(cdir1, cdir2)

-	local ang1 = advtrains.dir_to_angle(advtrains.oppd(cdir1))

-	local ang2 = advtrains.dir_to_angle(cdir2)

-	return ang1 + advtrains.minAngleDiffRad(ang1, ang2)/2

-end

-

-function advtrains.merge_tables(a, ...)

-	local new={}

-	for _,t in ipairs({a,...}) do

-		for k,v in pairs(t) do new[k]=v end

-	end

-	return new

-end

-function advtrains.save_keys(tbl, keys)

-	local new={}

-	for _,key in ipairs(keys) do

-		new[key] = tbl[key]

-	end

-	return new

-end

-

-function advtrains.get_real_index_position(path, index)

-	if not path or not index then return end

-	

-	local first_pos=path[math.floor(index)]

-	local second_pos=path[math.floor(index)+1]

-	

-	if not first_pos or not second_pos then return nil end

-	

-	local factor=index-math.floor(index)

-	local actual_pos={x=first_pos.x-(first_pos.x-second_pos.x)*factor, y=first_pos.y-(first_pos.y-second_pos.y)*factor, z=first_pos.z-(first_pos.z-second_pos.z)*factor,}

-	return actual_pos

-end

-function advtrains.pos_median(pos1, pos2)

-	return {x=pos1.x-(pos1.x-pos2.x)*0.5, y=pos1.y-(pos1.y-pos2.y)*0.5, z=pos1.z-(pos1.z-pos2.z)*0.5}

-end

-function advtrains.abs_ceil(i)

-	return math.ceil(math.abs(i))*math.sign(i)

-end

-

-function advtrains.serialize_inventory(inv)

-	local ser={}

-	local liszts=inv:get_lists()

-	for lisztname, liszt in pairs(liszts) do

-		ser[lisztname]={}

-		for idx, item in ipairs(liszt) do

-			local istring=item:to_string()

-			if istring~="" then

-				ser[lisztname][idx]=istring

-			end

-		end

-	end

-	return minetest.serialize(ser)

-end

-function advtrains.deserialize_inventory(sers, inv)

-	local ser=minetest.deserialize(sers)

-	if ser then

-		inv:set_lists(ser)

-		return true

-	end

-	return false

-end

-

---is_protected wrapper that checks for protection_bypass privilege

-function advtrains.is_protected(pos, name)

-	if not name then

-		error("advtrains.is_protected() called without name parameter!")

-	end

-	if minetest.check_player_privs(name, {protection_bypass=true}) then

-		--player can bypass protection

-		return false

-	end

-	return minetest.is_protected(pos, name)

-end

-

-function advtrains.is_creative(name)

-	if not name then

-		error("advtrains.is_creative() called without name parameter!")

-	end

-	if minetest.check_player_privs(name, {creative=true}) then

-		return true

-	end

-	return minetest.settings:get_bool("creative_mode")

-end

-

-function advtrains.is_damage_enabled(name)

-	if not name then

-		error("advtrains.is_damage_enabled() called without name parameter!")

-	end

-	if minetest.check_player_privs(name, "train_admin") then

-		return false

-	end

-	return minetest.settings:get_bool("enable_damage")

-end

-

-function advtrains.ms_to_kmh(speed)

-	return speed * 3.6

-end

-

--- 4 possible inputs:

--- integer: just do that modulo calculation

--- table with c set: rotate c

--- table with tables: rotate each

--- table with integers: rotate each (probably no use case)

-function advtrains.rotate_conn_by(conn, rotate)

-	if tonumber(conn) then

-		return (conn+rotate)%AT_CMAX

-	elseif conn.c then

-		return { c = (conn.c+rotate)%AT_CMAX, y = conn.y}

-	end

-	local tmp={}

-	for connid, data in ipairs(conn) do

-		tmp[connid]=advtrains.rotate_conn_by(data, rotate)

-	end

-	return tmp

-end

-

-

-function advtrains.oppd(dir)

-	return advtrains.rotate_conn_by(dir, AT_CMAX/2)

-end

---conn_to_match like rotate_conn_by

---other_conns have to be a table of conn tables!

-function advtrains.conn_matches_to(conn, other_conns)

-	if tonumber(conn) then

-		for connid, data in ipairs(other_conns) do

-			if advtrains.oppd(conn) == data.c then return connid end

-		end

-		return false

-	elseif conn.c then

-		for connid, data in ipairs(other_conns) do

-			local cmp = advtrains.oppd(conn)

-			if cmp.c == data.c and (cmp.y or 0) == (data.y or 0) then return connid end

-		end

-		return false

-	end

-	local tmp={}

-	for connid, data in ipairs(conn) do

-		local backmatch = advtrains.conn_matches_to(data, other_conns)

-		if backmatch then return backmatch, connid end --returns <connid of other rail> <connid of this rail>

-	end

-	return false

-end

-

--- Going from the rail at pos (does not need to be rounded) along connection with id conn_idx, if there is a matching rail, return it and the matching connid

--- returns: <adjacent pos>, <conn index of adjacent>, <my conn index>, <railheight of adjacent>

--- parameter this_conns_p is connection table of this rail and is optional, is determined by get_rail_info_at if not provided.

-function advtrains.get_adjacent_rail(this_posnr, this_conns_p, conn_idx, drives_on)

-	local this_pos = advtrains.round_vector_floor_y(this_posnr)

-	local this_conns = this_conns_p

-	if not this_conns then

-		_, this_conns = advtrains.get_rail_info_at(this_pos)

-	end

-	if not conn_idx then

-		for coni, _ in ipairs(this_conns) do

-			local adj_pos, adj_conn_idx, _, nry, nco = advtrains.get_adjacent_rail(this_pos, this_conns, coni)

-			if adj_pos then return adj_pos,adj_conn_idx,coni,nry, nco end

-		end

-		return nil

-	end

-	

-	local conn = this_conns[conn_idx]

-	local conn_y = conn.y or 0

-	local adj_pos = advtrains.dirCoordSet(this_pos, conn.c);

-	

-	while conn_y>=1 do

-		conn_y = conn_y - 1

-		adj_pos.y = adj_pos.y + 1

-	end

-	

-	local nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)

-	if not nextnode_ok then

-		adj_pos.y = adj_pos.y - 1

-		conn_y = conn_y + 1

-		nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)

-		if not nextnode_ok then

-			return nil

-		end

-	end

-	local adj_connid = advtrains.conn_matches_to({c=conn.c, y=conn_y}, nextconns)

-	if adj_connid then

-		return adj_pos, adj_connid, conn_idx, nextrail_y, nextconns

-	end

-	return nil

-end

-

--- when a train enters a rail on connid 'conn', which connid will it go out?

--- nconns: number of connections in connection table:

--- 2 = straight rail; 3 = turnout, 4 = crossing, 5 = three-way turnout (5th entry is a stub)

--- returns: connid_out

-local connlku={[2]={2,1}, [3]={2,1,1}, [4]={2,1,4,3}, [5]={2,1,1,1}}

-function advtrains.get_matching_conn(conn, nconns)

-	return connlku[nconns][conn]

-end

-

-function advtrains.random_id()

-	local idst=""

-	for i=0,5 do

-		idst=idst..(math.random(0,9))

-	end

-	return idst

-end

--- Shorthand for pos_to_string and round_vector_floor_y

-function advtrains.roundfloorpts(pos)

-	return minetest.pos_to_string(advtrains.round_vector_floor_y(pos))

-end

-

--- insert an element into a table if it does not yet exist there

--- equalfunc is a function to compare equality, defaults to ==

--- returns true if the element was inserted

-function advtrains.insert_once(tab, elem, equalfunc)

-	for _,e in pairs(tab) do

-		if equalfunc and equalfunc(elem, e) or e==elem then return false end

-	end

-	tab[#tab+1] = elem

-	return true

-end

-

-local hext = { [0]="0",[1]="1",[2]="2",[3]="3",[4]="4",[5]="5",[6]="6",[7]="7",[8]="8",[9]="9",[10]="A",[11]="B",[12]="C",[13]="D",[14]="E",[15]="F"}

-local dect = { ["0"]=0,["1"]=1,["2"]=2,["3"]=3,["4"]=4,["5"]=5,["6"]=6,["7"]=7,["8"]=8,["9"]=9,["A"]=10,["B"]=11,["C"]=12,["D"]=13,["E"]=14,["F"]=15}

-

-local f = atfloor

-

-local function hex(i)

-	local x=i+32768

-	local c4 = x % 16

-	x = f(x / 16)

-	local c3 = x % 16

-	x = f(x / 16)

-	local c2 = x % 16

-	x = f(x / 16)

-	local c1 = x % 16

-	return (hext[c1]) .. (hext[c2]) .. (hext[c3]) .. (hext[c4])

-end

-

-local function c(s,i) return dect[string.sub(s,i,i)] end

-

-local function dec(s)

-	return (c(s,1)*4096 + c(s,2)*256 + c(s,3)*16 + c(s,4))-32768

-end

--- Takes a position vector and outputs a encoded value suitable as table index

--- This is essentially a hexadecimal representation of the position (+32768)

--- Order (YYY)YXXXXZZZZ

-function advtrains.encode_pos(pos)

-	return hex(pos.y) .. hex(pos.x) .. hex(pos.z)

-end

-

--- decodes a position encoded with encode_pos

-function advtrains.decode_pos(pts)

-	if not pts or not #pts==6 then return nil end

-	local stry = string.sub(pts, 1,4)

-	local strx = string.sub(pts, 5,8)

-	local strz = string.sub(pts, 9,12)

-	return vector.new(dec(strx), dec(stry), dec(strz))

-end

-

---[[ Benchmarking code

-local tdt = {}

-local tlt = {}

-local tet = {}

-

-for i=1,1000000 do

-	tdt[i] = vector.new(math.random(-65536, 65535), math.random(-65536, 65535), math.random(-65536, 65535))

-	if i%1000 == 0 then

-		tlt[#tlt+1] = tdt[i]

-	end

-end

-

-local t1=os.clock()

-for i=1,1000000 do

-	local pe = advtrains.encode_pos(tdt[i])

-	local pb = advtrains.decode_pos(pe)

-	tet[pe] = i

-end

-for i,v in ipairs(tlt) do

-	local lk = tet[advtrains.encode_pos(v)]

-end

-atdebug("endec",os.clock()-t1,"s")

-

-tet = {}

-

-t1=os.clock()

-for i=1,1000000 do

-	local pe = minetest.pos_to_string(tdt[i])

-	local pb = minetest.string_to_pos(pe)

-	tet[pe] = i

-end

-for i,v in ipairs(tlt) do

-	local lk = tet[minetest.pos_to_string(v)]

-end

-atdebug("pts",os.clock()-t1,"s")

-

---Results:

---2018-11-29 16:57:08: ACTION[Main]: [advtrains]endec 1.786451 s 

---2018-11-29 16:57:10: ACTION[Main]: [advtrains]pts 2.566377 s 

-]]

-

-

+--advtrains by orwell96, see readme.txt
+
+local dir_trans_tbl={
+	[0]={x=0, z=1, y=0},
+	[1]={x=1, z=2, y=0},
+	[2]={x=1, z=1, y=0},
+	[3]={x=2, z=1, y=0},
+	[4]={x=1, z=0, y=0},
+	[5]={x=2, z=-1, y=0},
+	[6]={x=1, z=-1, y=0},
+	[7]={x=1, z=-2, y=0},
+	[8]={x=0, z=-1, y=0},
+	[9]={x=-1, z=-2, y=0},
+	[10]={x=-1, z=-1, y=0},
+	[11]={x=-2, z=-1, y=0},
+	[12]={x=-1, z=0, y=0},
+	[13]={x=-2, z=1, y=0},
+	[14]={x=-1, z=1, y=0},
+	[15]={x=-1, z=2, y=0},
+}
+
+local dir_angle_tbl={}
+for d,v in pairs(dir_trans_tbl) do
+	local uvec = vector.normalize(v)
+	dir_angle_tbl[d] = math.atan2(-uvec.x, uvec.z)
+end
+
+
+function advtrains.dir_to_angle(dir)
+	return dir_angle_tbl[dir] or error("advtrains: in helpers.lua/dir_to_angle() given dir="..(dir or "nil"))
+end
+
+function advtrains.dirCoordSet(coord, dir)
+	return vector.add(coord, advtrains.dirToCoord(dir))
+end
+advtrains.pos_add_dir = advtrains.dirCoordSet
+
+function advtrains.pos_add_angle(pos, ang)
+	-- 0 is +Z -> meaning of sin/cos swapped
+	return vector.add(pos, {x = -math.sin(ang), y = 0, z = math.cos(ang)})
+end
+
+function advtrains.dirToCoord(dir)
+	return dir_trans_tbl[dir] or error("advtrains: in helpers.lua/dir_to_vector() given dir="..(dir or "nil"))
+end
+advtrains.dir_to_vector = advtrains.dirToCoord
+
+function advtrains.maxN(list, expectstart)
+	local n=expectstart or 0
+	while list[n] do
+		n=n+1
+	end
+	return n-1
+end
+
+function advtrains.minN(list, expectstart)
+	local n=expectstart or 0
+	while list[n] do
+		n=n-1
+	end
+	return n+1
+end
+
+function atround(number)
+	return math.floor(number+0.5)
+end
+atfloor = math.floor
+
+
+function advtrains.round_vector_floor_y(vec)
+	return {x=math.floor(vec.x+0.5), y=math.floor(vec.y), z=math.floor(vec.z+0.5)}
+end
+
+function advtrains.yawToDirection(yaw, conn1, conn2)
+	if not conn1 or not conn2 then
+		error("given nil to yawToDirection: conn1="..(conn1 or "nil").." conn2="..(conn1 or "nil"))
+	end
+	local yaw1 = advtrains.dir_to_angle(conn1)
+	local yaw2 = advtrains.dir_to_angle(conn2)
+	local adiff1 = advtrains.minAngleDiffRad(yaw, yaw1)
+	local adiff2 = advtrains.minAngleDiffRad(yaw, yaw2)
+	
+	if math.abs(adiff2)<math.abs(adiff1) then
+		return conn2
+	else
+		return conn1
+	end
+end
+
+function advtrains.yawToAnyDir(yaw)
+	local min_conn, min_diff=0, 10
+	for conn, vec in pairs(advtrains.dir_trans_tbl) do
+		local yaw1 = advtrains.dir_to_angle(conn)
+		local diff = math.abs(advtrains.minAngleDiffRad(yaw, yaw1))
+		if diff < min_diff then
+			min_conn = conn
+			min_diff = diff
+		end
+	end
+	return min_conn
+end
+function advtrains.yawToClosestConn(yaw, conns)
+	local min_connid, min_diff=1, 10
+	for connid, conn in ipairs(conns) do
+		local yaw1 = advtrains.dir_to_angle(conn.c)
+		local diff = math.abs(advtrains.minAngleDiffRad(yaw, yaw1))
+		if diff < min_diff then
+			min_connid = connid
+			min_diff = diff
+		end
+	end
+	return min_connid
+end
+
+local pi, pi2 = math.pi, 2*math.pi
+function advtrains.minAngleDiffRad(r1, r2)
+	while r1>pi2 do
+		r1=r1-pi2
+	end
+	while r1<0 do
+		r1=r1+pi2
+	end
+	while r2>pi2 do
+		r2=r2-pi2
+	end
+	while r1<0 do
+		r2=r2+pi2
+	end
+	local try1=r2-r1
+	local try2=r2+pi2-r1
+	local try3=r2-pi2-r1
+	
+	local minabs = math.min(math.abs(try1), math.abs(try2), math.abs(try3))
+	if minabs==math.abs(try1) then
+		return try1
+	end
+	if minabs==math.abs(try2) then
+		return try2
+	end
+	if minabs==math.abs(try3) then
+		return try3
+	end
+end
+
+
+-- Takes 2 connections (0...AT_CMAX) as argument
+-- Returns the angle median of those 2 positions from the pov
+-- of standing on the cdir1 side and looking towards cdir2
+-- cdir1 - >NODE> - cdir2
+function advtrains.conn_angle_median(cdir1, cdir2)
+	local ang1 = advtrains.dir_to_angle(advtrains.oppd(cdir1))
+	local ang2 = advtrains.dir_to_angle(cdir2)
+	return ang1 + advtrains.minAngleDiffRad(ang1, ang2)/2
+end
+
+function advtrains.merge_tables(a, ...)
+	local new={}
+	for _,t in ipairs({a,...}) do
+		for k,v in pairs(t) do new[k]=v end
+	end
+	return new
+end
+function advtrains.save_keys(tbl, keys)
+	local new={}
+	for _,key in ipairs(keys) do
+		new[key] = tbl[key]
+	end
+	return new
+end
+
+function advtrains.get_real_index_position(path, index)
+	if not path or not index then return end
+	
+	local first_pos=path[math.floor(index)]
+	local second_pos=path[math.floor(index)+1]
+	
+	if not first_pos or not second_pos then return nil end
+	
+	local factor=index-math.floor(index)
+	local actual_pos={x=first_pos.x-(first_pos.x-second_pos.x)*factor, y=first_pos.y-(first_pos.y-second_pos.y)*factor, z=first_pos.z-(first_pos.z-second_pos.z)*factor,}
+	return actual_pos
+end
+function advtrains.pos_median(pos1, pos2)
+	return {x=pos1.x-(pos1.x-pos2.x)*0.5, y=pos1.y-(pos1.y-pos2.y)*0.5, z=pos1.z-(pos1.z-pos2.z)*0.5}
+end
+function advtrains.abs_ceil(i)
+	return math.ceil(math.abs(i))*math.sign(i)
+end
+
+function advtrains.serialize_inventory(inv)
+	local ser={}
+	local liszts=inv:get_lists()
+	for lisztname, liszt in pairs(liszts) do
+		ser[lisztname]={}
+		for idx, item in ipairs(liszt) do
+			local istring=item:to_string()
+			if istring~="" then
+				ser[lisztname][idx]=istring
+			end
+		end
+	end
+	return minetest.serialize(ser)
+end
+function advtrains.deserialize_inventory(sers, inv)
+	local ser=minetest.deserialize(sers)
+	if ser then
+		inv:set_lists(ser)
+		return true
+	end
+	return false
+end
+
+--is_protected wrapper that checks for protection_bypass privilege
+function advtrains.is_protected(pos, name)
+	if not name then
+		error("advtrains.is_protected() called without name parameter!")
+	end
+	if minetest.check_player_privs(name, {protection_bypass=true}) then
+		--player can bypass protection
+		return false
+	end
+	return minetest.is_protected(pos, name)
+end
+
+function advtrains.is_creative(name)
+	if not name then
+		error("advtrains.is_creative() called without name parameter!")
+	end
+	if minetest.check_player_privs(name, {creative=true}) then
+		return true
+	end
+	return minetest.settings:get_bool("creative_mode")
+end
+
+function advtrains.is_damage_enabled(name)
+	if not name then
+		error("advtrains.is_damage_enabled() called without name parameter!")
+	end
+	if minetest.check_player_privs(name, "train_admin") then
+		return false
+	end
+	return minetest.settings:get_bool("enable_damage")
+end
+
+function advtrains.ms_to_kmh(speed)
+	return speed * 3.6
+end
+
+-- 4 possible inputs:
+-- integer: just do that modulo calculation
+-- table with c set: rotate c
+-- table with tables: rotate each
+-- table with integers: rotate each (probably no use case)
+function advtrains.rotate_conn_by(conn, rotate)
+	if tonumber(conn) then
+		return (conn+rotate)%AT_CMAX
+	elseif conn.c then
+		return { c = (conn.c+rotate)%AT_CMAX, y = conn.y}
+	end
+	local tmp={}
+	for connid, data in ipairs(conn) do
+		tmp[connid]=advtrains.rotate_conn_by(data, rotate)
+	end
+	return tmp
+end
+
+
+function advtrains.oppd(dir)
+	return advtrains.rotate_conn_by(dir, AT_CMAX/2)
+end
+--conn_to_match like rotate_conn_by
+--other_conns have to be a table of conn tables!
+function advtrains.conn_matches_to(conn, other_conns)
+	if tonumber(conn) then
+		for connid, data in ipairs(other_conns) do
+			if advtrains.oppd(conn) == data.c then return connid end
+		end
+		return false
+	elseif conn.c then
+		for connid, data in ipairs(other_conns) do
+			local cmp = advtrains.oppd(conn)
+			if cmp.c == data.c and (cmp.y or 0) == (data.y or 0) then return connid end
+		end
+		return false
+	end
+	local tmp={}
+	for connid, data in ipairs(conn) do
+		local backmatch = advtrains.conn_matches_to(data, other_conns)
+		if backmatch then return backmatch, connid end --returns <connid of other rail> <connid of this rail>
+	end
+	return false
+end
+
+-- Going from the rail at pos (does not need to be rounded) along connection with id conn_idx, if there is a matching rail, return it and the matching connid
+-- returns: <adjacent pos>, <conn index of adjacent>, <my conn index>, <railheight of adjacent>
+-- parameter this_conns_p is connection table of this rail and is optional, is determined by get_rail_info_at if not provided.
+function advtrains.get_adjacent_rail(this_posnr, this_conns_p, conn_idx, drives_on)
+	local this_pos = advtrains.round_vector_floor_y(this_posnr)
+	local this_conns = this_conns_p
+	if not this_conns then
+		_, this_conns = advtrains.get_rail_info_at(this_pos)
+	end
+	if not conn_idx then
+		for coni, _ in ipairs(this_conns) do
+			local adj_pos, adj_conn_idx, _, nry, nco = advtrains.get_adjacent_rail(this_pos, this_conns, coni)
+			if adj_pos then return adj_pos,adj_conn_idx,coni,nry, nco end
+		end
+		return nil
+	end
+	
+	local conn = this_conns[conn_idx]
+	local conn_y = conn.y or 0
+	local adj_pos = advtrains.dirCoordSet(this_pos, conn.c);
+	
+	while conn_y>=1 do
+		conn_y = conn_y - 1
+		adj_pos.y = adj_pos.y + 1
+	end
+	
+	local nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)
+	if not nextnode_ok then
+		adj_pos.y = adj_pos.y - 1
+		conn_y = conn_y + 1
+		nextnode_ok, nextconns, nextrail_y=advtrains.get_rail_info_at(adj_pos, drives_on)
+		if not nextnode_ok then
+			return nil
+		end
+	end
+	local adj_connid = advtrains.conn_matches_to({c=conn.c, y=conn_y}, nextconns)
+	if adj_connid then
+		return adj_pos, adj_connid, conn_idx, nextrail_y, nextconns
+	end
+	return nil
+end
+
+-- when a train enters a rail on connid 'conn', which connid will it go out?
+-- nconns: number of connections in connection table:
+-- 2 = straight rail; 3 = turnout, 4 = crossing, 5 = three-way turnout (5th entry is a stub)
+-- returns: connid_out
+local connlku={[2]={2,1}, [3]={2,1,1}, [4]={2,1,4,3}, [5]={2,1,1,1}}
+function advtrains.get_matching_conn(conn, nconns)
+	return connlku[nconns][conn]
+end
+
+function advtrains.random_id()
+	local idst=""
+	for i=0,5 do
+		idst=idst..(math.random(0,9))
+	end
+	return idst
+end
+-- Shorthand for pos_to_string and round_vector_floor_y
+function advtrains.roundfloorpts(pos)
+	return minetest.pos_to_string(advtrains.round_vector_floor_y(pos))
+end
+
+-- insert an element into a table if it does not yet exist there
+-- equalfunc is a function to compare equality, defaults to ==
+-- returns true if the element was inserted
+function advtrains.insert_once(tab, elem, equalfunc)
+	for _,e in pairs(tab) do
+		if equalfunc and equalfunc(elem, e) or e==elem then return false end
+	end
+	tab[#tab+1] = elem
+	return true
+end
+
+local hext = { [0]="0",[1]="1",[2]="2",[3]="3",[4]="4",[5]="5",[6]="6",[7]="7",[8]="8",[9]="9",[10]="A",[11]="B",[12]="C",[13]="D",[14]="E",[15]="F"}
+local dect = { ["0"]=0,["1"]=1,["2"]=2,["3"]=3,["4"]=4,["5"]=5,["6"]=6,["7"]=7,["8"]=8,["9"]=9,["A"]=10,["B"]=11,["C"]=12,["D"]=13,["E"]=14,["F"]=15}
+
+local f = atfloor
+
+local function hex(i)
+	local x=i+32768
+	local c4 = x % 16
+	x = f(x / 16)
+	local c3 = x % 16
+	x = f(x / 16)
+	local c2 = x % 16
+	x = f(x / 16)
+	local c1 = x % 16
+	return (hext[c1]) .. (hext[c2]) .. (hext[c3]) .. (hext[c4])
+end
+
+local function c(s,i) return dect[string.sub(s,i,i)] end
+
+local function dec(s)
+	return (c(s,1)*4096 + c(s,2)*256 + c(s,3)*16 + c(s,4))-32768
+end
+-- Takes a position vector and outputs a encoded value suitable as table index
+-- This is essentially a hexadecimal representation of the position (+32768)
+-- Order (YYY)YXXXXZZZZ
+function advtrains.encode_pos(pos)
+	return hex(pos.y) .. hex(pos.x) .. hex(pos.z)
+end
+
+-- decodes a position encoded with encode_pos
+function advtrains.decode_pos(pts)
+	if not pts or not #pts==6 then return nil end
+	local stry = string.sub(pts, 1,4)
+	local strx = string.sub(pts, 5,8)
+	local strz = string.sub(pts, 9,12)
+	return vector.new(dec(strx), dec(stry), dec(strz))
+end
+
+--[[ Benchmarking code
+local tdt = {}
+local tlt = {}
+local tet = {}
+
+for i=1,1000000 do
+	tdt[i] = vector.new(math.random(-65536, 65535), math.random(-65536, 65535), math.random(-65536, 65535))
+	if i%1000 == 0 then
+		tlt[#tlt+1] = tdt[i]
+	end
+end
+
+local t1=os.clock()
+for i=1,1000000 do
+	local pe = advtrains.encode_pos(tdt[i])
+	local pb = advtrains.decode_pos(pe)
+	tet[pe] = i
+end
+for i,v in ipairs(tlt) do
+	local lk = tet[advtrains.encode_pos(v)]
+end
+atdebug("endec",os.clock()-t1,"s")
+
+tet = {}
+
+t1=os.clock()
+for i=1,1000000 do
+	local pe = minetest.pos_to_string(tdt[i])
+	local pb = minetest.string_to_pos(pe)
+	tet[pe] = i
+end
+for i,v in ipairs(tlt) do
+	local lk = tet[minetest.pos_to_string(v)]
+end
+atdebug("pts",os.clock()-t1,"s")
+
+--Results:
+--2018-11-29 16:57:08: ACTION[Main]: [advtrains]endec 1.786451 s 
+--2018-11-29 16:57:10: ACTION[Main]: [advtrains]pts 2.566377 s 
+]]
+
+