created git repository

1 files changed, 121 insertions, 0 deletions

diff --git a/pseudoload.lua b/pseudoload.lua
new file mode 100644
index 0000000..532b429
--- /dev/null
+++ b/pseudoload.lua
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+
+--pseudoload.lua
+--responsible for keeping up a database of all rail nodes existant in the world, regardless of whether the mapchunk is loaded.
+
+advtrains.trackdb={}
+--trackdb[y][x][z]={conn1, conn2, rely1, rely2, railheight}
+--serialization format:
+--(2byte x)(2byte y)(2byte z)(4bits conn1, 4bits conn2)[(plain rely1)|(plain rely2)|(plain railheight)]\n
+--[] may be missing if 0,0,0
+
+--load initially
+advtrains.pl_fpath=minetest.get_worldpath().."/advtrains_trackdb"
+local file, err = io.open(advtrains.pl_fpath, "r")
+if not file then
+	local er=err or "Unknown Error"
+	print("[advtrains]Failed loading advtrains trackdb save file "..er)
+else
+	--custom format to save memory
+	while true do
+		local xbytes=file:read(2)
+		if not xbytes then
+			break --eof reached
+		end
+		local ybytes=file:read(2)
+		local zbytes=file:read(2)
+		local x=(string.byte(xbytes[1])-128)*256+(string.byte(xbytes[2]))
+		local y=(string.byte(ybytes[1])-128)*256+(string.byte(ybytes[2]))
+		local z=(string.byte(zbytes[1])-128)*256+(string.byte(zbytes[2]))
+		
+		local conn1=string.byte(file:read(1))
+		local conn1=string.byte(file:read(1))
+		
+		if not advtrains.trackdb[y] then advtrains.trackdb[y]={} end
+		if not advtrains.trackdb[y][x] then advtrains.trackdb[y][x]={} end
+		
+		local rest=file.read("*l")
+		if rest~="" then
+			local rely1, rely2, railheight=string.match(rest, "([^|]+)|([^|]+)|([^|]+)")
+			if rely1 and rely2 and railheight then
+				advtrains.trackdb[y][x][z]={
+					conn1=conn1, conn2=conn2,
+					rely1=rely1, rely2=rely2,
+					railheight=railheight
+				}
+			else
+				advtrains.trackdb[y][x][z]={
+					conn1=conn1, conn2=conn2
+				}
+			end
+		else
+			advtrains.trackdb[y][x][z]={
+				conn1=conn1, conn2=conn2
+			}
+		end
+	end
+	file:close()
+end
+function advtrains.save_trackdb()
+	local file, err = io.open(advtrains.pl_fpath, "w")
+	if not file then
+		local er=err or "Unknown Error"
+		print("[advtrains]Failed saving advtrains trackdb save file "..er)
+	else
+		--custom format to save memory
+		for x,txl in pairs(advtrains.trackdb) do
+			for y,tyl in pairs(txl) do
+				for z,rail in pairs(tyl) do
+					file:write(string.char(math.floor(x/256)+128)..string.char((x%256)))
+					file:write(string.char(math.floor(y/256)+128)..string.char((y%256)))
+					file:write(string.char(math.floor(z/256)+128)..string.char((z%256)))
+					file:write(string.char(rail.conn1))
+					file:write(string.char(rail.conn2))
+					if (rail.rely1 and rail.rely1~=0) or (rail.rely2 and rail.rely2~=0) or (rail.railheight and rail.railheight~=0) then
+						file:write(rail.rely1.."|"..rail.rely2.."|"..rail.railheight)
+					end
+					file:write("\n")
+				end
+			end
+		end
+		file:close()
+	end
+end
+
+--get_node with pseudoload.
+--returns:
+--true, conn1, conn2, rely1, rely2, railheight   in case everything's right.
+--false  if it's not a rail or the train does not drive on this rail, but it is loaded or
+--nil    if the node is neither loaded nor in trackdb
+--the distraction between false and nil will be needed only in special cases.(train initpos)
+function advtrains.get_rail_info_at(pos, traintype)
+	local node=minetest.get_node_or_nil(pos)
+	if not node then
+		--try raildb
+		local rdp=vector.round(rdp)
+		local dbe=advtrains.trackdb[rdp.y][rdp.x][rdp.z]
+		if dbe then
+			return true, dbe.conn1, dbe.conn2, dbe.rely1 or 0, dbe.rely2 or 0, dbe.railheight or 0
+		else
+			return nil
+		end
+	end
+	local nodename=node.name
+	if(not advtrains.is_track_and_drives_on(nodename, advtrains.all_traintypes[traintype].drives_on)) then
+		return false
+	end
+	local conn1, conn2, rely1, rely2, railheight=advtrains.get_track_connections(node.name, node.param2)
+	
+	--already in trackdb?
+	local rdp=vector.round(rdp)
+	if not advtrains.trackdb[rdp.y][rdp.x][rdp.z] then--TODO is this write prevention here really needed?
+		advtrains.trackdb[rdp.y][rdp.x][rdp.z]={
+			conn1=conn1, conn2=conn2,
+			rely1=rely1, rely2=rely2,
+			railheight=railheight
+		}
+	end
+	
+	return true, conn1, conn2, rely1, rely2, railheight
+end
+
+