Clean up serialization

  * Adds a header to serialized data (to make version checking sane).
  * Removes the duplicate deserialization for `worldedit.deserialize` and `worldedit.allocate`.
  * Optimizes `worldedit.deserialize` by only deserializing the data once.
  * Makes some fields optional.
  * Cleans up the comments and a little of the code style.

5 files changed, 217 insertions, 225 deletions

diff --git a/README.md b/README.md
index 224059e..7d3077b 100644
--- a/README.md
+++ b/README.md
@@ -109,20 +109,24 @@ WorldEdit supports two different types of schematics.
 
 The first is the WorldEdit Schematic format, with the file extension ".we", and in some older versions, ".wem". There have been several previous versions of the WorldEdit Schematic format, but WorldEdit is capable of loading any past versions, and will always support them - there is no need to worry about schematics becoming obselete.
 
-The current version of the WorldEdit Schematic format, internally known as version 4, is essentially an array of node data tables in Lua 5.2 table syntax. Specifically:
-
-    return {
-        {
-            ["y"]      = <y-axis coordinate>,
-            ["x"]      = <x-axis coordinate>,
-            ["name"]   = <node name>,
-            ["z"]      = <z-axis coordinate>,
-            ["meta"]   = <metadata table>,
-            ["param2"] = <param2 value>,
-            ["param1"] = <y-axis coordinate>,
-        },
-        <...>
-    }
+As of version 5, WorldEdit schematics include a header.  The header is seperated from the content by a colon (`:`).  It contains fields seperated by commas (`,`).  Currently only one field is used, which contains the version in ASCII decimal.
+
+The current version of the WorldEdit Schematic format is essentially an array of node data tables in Lua 5.1 table syntax preceded by a header.
+Specifically it looks like this:
+
+	5:return {
+		{
+			y      = <y-axis coordinate>,
+			x      = <x-axis coordinate>,
+			z      = <z-axis coordinate>,
+			name   = <node name>,
+			param1 = <param1 value>,
+			param2 = <param2 value>,
+			meta   = <metadata table>,
+		},
+		<...>
+	}
+
 
 The ordering of the values and minor aspects of the syntax, such as trailing commas or newlines, are not guaranteed to stay the same in future versions.
 
diff --git a/WorldEdit API.md b/WorldEdit API.md
index 8f4b7d2..af7138b 100644
--- a/WorldEdit API.md
+++ b/WorldEdit API.md
@@ -195,29 +195,30 @@ Serialization
 -------------

 Contained in serialization.lua, this module allows regions of nodes to be serialized and deserialized to formats suitable for use outside MineTest.

 

-### version = worldedit.valueversion(value)

+### version, extra_fields, content = worldedit.read_header(value)

 

-Determines the version of serialized data `value`.

+Reads the header from serialized data `value`.

 

-Returns the version as a positive integer or 0 for unknown versions.

+Returns the version as a positive integer (nil for unknown versions),

+extra header fields (nil if not supported), and the content after the header.

 

 ### data, count = worldedit.serialize(pos1, pos2)

 

 Converts the region defined by positions `pos1` and `pos2` into a single string.

 

-Returns the serialized data and the number of nodes serialized.

+Returns the serialized data and the number of nodes serialized, or nil.

 

-### pos1, pos2, count = worldedit.allocate(originpos, value)

+### pos1, pos2, count = worldedit.allocate(origin_pos, value)

 

-Determines the volume the nodes represented by string `value` would occupy if deserialized at `originpos`.

+Determines the volume the nodes represented by string `value` would occupy if deserialized at `origin_pos`.

 

-Returns the two corner positions and the number of nodes.

+Returns the two corner positions and the number of nodes, or nil.

 

-### count = worldedit.deserialize(originpos, value)

+### count = worldedit.deserialize(origin_pos, value)

 

-Loads the nodes represented by string `value` at position `originpos`.

+Loads the nodes represented by string `value` at position `origin_pos`.

 

-Returns the number of nodes deserialized.

+Returns the number of nodes deserialized or nil.

 

 Code

 ----

@@ -233,4 +234,4 @@ Returns an error if the code fails or nil otherwise.
 

 Executes `code` as a Lua chunk in the global namespace with the variable `pos` available, for each node in a region defined by positions `pos1` and `pos2`.

 

-Returns an error if the code fails or nil otherwise.
\ No newline at end of file
+Returns an error if the code fails or nil otherwise.

diff --git a/worldedit/compatibility.lua b/worldedit/compatibility.lua
index ff3447f..e44e43b 100644
--- a/worldedit/compatibility.lua
+++ b/worldedit/compatibility.lua
@@ -2,7 +2,9 @@ worldedit = worldedit or {}
 local minetest = minetest --local copy of global

 

 worldedit.allocate_old = worldedit.allocate

+

 worldedit.deserialize_old = worldedit.deserialize

+

 worldedit.metasave = function(pos1, pos2, filename)

 	local file, err = io.open(filename, "wb")

 	if err then return 0 end

@@ -11,6 +13,7 @@ worldedit.metasave = function(pos1, pos2, filename)
 	file:close()

 	return count

 end

+

 worldedit.metaload = function(originpos, filename)

 	filename = minetest.get_worldpath() .. "/schems/" .. file .. ".wem"

 	local file, err = io.open(filename, "wb")

@@ -18,6 +21,16 @@ worldedit.metaload = function(originpos, filename)
 	local data = file:read("*a")

 	return worldedit.deserialize(originpos, data)

 end

+

 worldedit.scale = function(pos1, pos2, factor)

 	return worldedit.stretch(pos1, pos2, factor, factor, factor)

-end
\ No newline at end of file
+end

+

+worldedit.valueversion = function(value)

+	local version = worldedit.read_header(value)

+	if not version or version > worldedit.LATEST_SERIALIZATION_VERSION then

+		return 0

+	end

+	return version

+end

+

diff --git a/worldedit/serialization.lua b/worldedit/serialization.lua
index bbedca5..4d28988 100644
--- a/worldedit/serialization.lua
+++ b/worldedit/serialization.lua
@@ -1,40 +1,58 @@
 worldedit = worldedit or {}

-local minetest = minetest --local copy of global

-

---modifies positions `pos1` and `pos2` so that each component of `pos1` is less than or equal to its corresponding conent of `pos2`, returning two new positions

-worldedit.sort_pos = function(pos1, pos2)

-	pos1 = {x=pos1.x, y=pos1.y, z=pos1.z}

-	pos2 = {x=pos2.x, y=pos2.y, z=pos2.z}

-	if pos1.x > pos2.x then

-		pos2.x, pos1.x = pos1.x, pos2.x

-	end

-	if pos1.y > pos2.y then

-		pos2.y, pos1.y = pos1.y, pos2.y

+local minetest = minetest -- Local copy of global

+

+worldedit.LATEST_SERIALIZATION_VERSION = 5

+local LATEST_SERIALIZATION_HEADER = worldedit.LATEST_SERIALIZATION_VERSION .. ":"

+

+

+--[[

+Serialization version history:

+  1: Original format.  Serialized Lua table with a weird linked format...

+  2: Position and node seperated into sub-tables in fields `1` and `2`.

+  3: List of nodes, one per line, with fields seperated by spaces.

+      Format: <X> <Y> <Z> <Name> <Param1> <Param2>

+  4: Serialized Lua table containing a list of nodes with `x`, `y`, `z`,

+      `name`, `param1`, `param2`, and `meta` fields.

+  5: Added header and made `param1`, `param2`, and `meta` fields optional.

+      Header format: <Version>,<ExtraHeaderField1>,...:<Content>

+--]]

+

+

+--- Reads the header of serialized data.

+-- @param value Serialized WorldEdit data.

+-- @return The version as a positive natural number, or 0 for unknown versions.

+-- @return Extra header fields as a list of strings, or nil if not supported.

+-- @return Content (data after header).

+function worldedit.read_header(value)

+	if value:find("^[0-9]+[%-:]") then

+		local header_end = value:find(":", 1, true)

+		local header = value:sub(1, header_end - 1):split(",")

+		local version = tonumber(header[1])

+		table.remove(header, 1)

+		local content = value:sub(header_end + 1)

+		return version, header, content

 	end

-	if pos1.z > pos2.z then

-		pos2.z, pos1.z = pos1.z, pos2.z

-	end

-	return pos1, pos2

-end

-

---determines the version of serialized data `value`, returning the version as a positive integer or 0 for unknown versions

-worldedit.valueversion = function(value)

-	if value:find("([+-]?%d+)%s+([+-]?%d+)%s+([+-]?%d+)") and not value:find("%{") then --previous list format

-		return 3

+	-- Old versions that didn't include a header with a version number

+	if value:find("([+-]?%d+)%s+([+-]?%d+)%s+([+-]?%d+)") and not value:find("%{") then -- List format

+		return 3, nil, value

 	elseif value:find("^[^\"']+%{%d+%}") then

-		if value:find("%[\"meta\"%]") then --previous meta flat table format

-			return 2

+		if value:find("%[\"meta\"%]") then -- Meta flat table format

+			return 2, nil, value

 		end

-		return 1 --original flat table format

-	elseif value:find("%{") then --current nested table format

-		return 4

+		return 1, nil, value -- Flat table format

+	elseif value:find("%{") then -- Raw nested table format

+		return 4, nil, value

 	end

-	return 0 --unknown format

+	return nil

 end

 

---converts the region defined by positions `pos1` and `pos2` into a single string, returning the serialized data and the number of nodes serialized

-worldedit.serialize = function(pos1, pos2)

-	--make area stay loaded

+

+--- Converts the region defined by positions `pos1` and `pos2`

+-- into a single string.

+-- @return The serialized data.

+-- @return The number of nodes serialized.

+function worldedit.serialize(pos1, pos2)

+	-- Keep area loaded

 	local manip = minetest.get_voxel_manip()

 	manip:read_from_map(pos1, pos2)

 

@@ -53,21 +71,29 @@ worldedit.serialize = function(pos1, pos2)
 					count = count + 1

 					local meta = get_meta(pos):to_table()

 

-					--convert metadata itemstacks to itemstrings

+					local meta_empty = true

+					-- Convert metadata item stacks to item strings

 					for name, inventory in pairs(meta.inventory) do

 						for index, stack in ipairs(inventory) do

+							meta_empty = false

 							inventory[index] = stack.to_string and stack:to_string() or stack

 						end

 					end

+					for k in pairs(meta) do

+						if k ~= "inventory" then

+							meta_empty = false

+							break

+						end

+					end

 

 					result[count] = {

 						x = pos.x - pos1.x,

 						y = pos.y - pos1.y,

 						z = pos.z - pos1.z,

 						name = node.name,

-						param1 = node.param1,

-						param2 = node.param2,

-						meta = meta,

+						param1 = node.param1 ~= 0 and node.param1 or nil,

+						param2 = node.param2 ~= 0 and node.param2 or nil,

+						meta = not meta_empty and meta or nil,

 					}

 				end

 				pos.z = pos.z + 1

@@ -76,28 +102,24 @@ worldedit.serialize = function(pos1, pos2)
 		end

 		pos.x = pos.x + 1

 	end

-	result = minetest.serialize(result) --convert entries to a string

-	return result, count

+	-- Serialize entries

+	result = minetest.serialize(result)

+	return LATEST_SERIALIZATION_HEADER .. result, count

 end

 

---determines the volume the nodes represented by string `value` would occupy if deserialized at `originpos`, returning the two corner positions and the number of nodes

---contains code based on [table.save/table.load](http://lua-users.org/wiki/SaveTableToFile) by ChillCode, available under the MIT license (GPL compatible)

-worldedit.allocate = function(originpos, value)

-	local huge = math.huge

-	local pos1x, pos1y, pos1z = huge, huge, huge

-	local pos2x, pos2y, pos2z = -huge, -huge, -huge

-	local originx, originy, originz = originpos.x, originpos.y, originpos.z

-	local count = 0

-	local version = worldedit.valueversion(value)

-	if version == 1 or version == 2 then --flat table format

-		--obtain the node table

-		local get_tables = loadstring(value)

-		if get_tables then --error loading value

-			return originpos, originpos, count

-		end

-		local tables = get_tables()

 

-		--transform the node table into an array of nodes

+--- Loads the schematic in `value` into a node list in the latest format.

+-- Contains code based on [table.save/table.load](http://lua-users.org/wiki/SaveTableToFile)

+-- by ChillCode, available under the MIT license.

+-- @return A node list in the latest format, or nil on failure.

+function worldedit.load_schematic(value)

+	local version, header, content = worldedit.read_header(value)

+	local nodes

+	if version == 1 or version == 2 then -- Original flat table format

+		local tables = minetest.deserialize(content)

+		if not tables then return nil end

+

+		-- Transform the node table into an array of nodes

 		for i = 1, #tables do

 			for j, v in pairs(tables[i]) do

 				if type(v) == "table" then

@@ -105,169 +127,114 @@ worldedit.allocate = function(originpos, value)
 				end

 			end

 		end

-		local nodes = tables[1]

+		nodes = tables[1]

 

-		--check the node array

-		count = #nodes

 		if version == 1 then --original flat table format

-			for index = 1, count do

-				local entry = nodes[index]

+			for i, entry in ipairs(nodes) do

 				local pos = entry[1]

-				local x, y, z = originx - pos.x, originy - pos.y, originz - pos.z

-				if x < pos1x then pos1x = x end

-				if y < pos1y then pos1y = y end

-				if z < pos1z then pos1z = z end

-				if x > pos2x then pos2x = x end

-				if y > pos2y then pos2y = y end

-				if z > pos2z then pos2z = z end

-			end

-		else --previous meta flat table format

-			for index = 1, count do

-				local entry = nodes[index]

-				local x, y, z = originx - entry.x, originy - entry.y, originz - entry.z

-				if x < pos1x then pos1x = x end

-				if y < pos1y then pos1y = y end

-				if z < pos1z then pos1z = z end

-				if x > pos2x then pos2x = x end

-				if y > pos2y then pos2y = y end

-				if z > pos2z then pos2z = z end

+				entry.x, entry.y, entry.z = pos.x, pos.y, pos.z

+				entry[1] = nil

+				local node = entry[2]

+				entry.name, entry.param1, entry.param2 = node.name, node.param1, node.param2

+				entry[2] = nil

 			end

 		end

-	elseif version == 3 then --previous list format

-		for x, y, z, name, param1, param2 in value:gmatch("([+-]?%d+)%s+([+-]?%d+)%s+([+-]?%d+)%s+([^%s]+)%s+(%d+)%s+(%d+)[^\r\n]*[\r\n]*") do --match node entries

-			x, y, z = originx + tonumber(x), originy + tonumber(y), originz + tonumber(z)

-			if x < pos1x then pos1x = x end

-			if y < pos1y then pos1y = y end

-			if z < pos1z then pos1z = z end

-			if x > pos2x then pos2x = x end

-			if y > pos2y then pos2y = y end

-			if z > pos2z then pos2z = z end

-			count = count + 1

+	elseif version == 3 then -- List format

+		for x, y, z, name, param1, param2 in content:gmatch(

+				"([+-]?%d+)%s+([+-]?%d+)%s+([+-]?%d+)%s+" ..

+				"([^%s]+)%s+(%d+)%s+(%d+)[^\r\n]*[\r\n]*") do

+			param1, param2 = tonumber(param1), tonumber(param2)

+			table.insert(nodes, {

+				x = originx + tonumber(x),

+				y = originy + tonumber(y),

+				z = originz + tonumber(z),

+				name = name,

+				param1 = param1 ~= 0 and param1 or nil,

+				param2 = param2 ~= 0 and param2 or nil,

+			})

 		end

-	elseif version == 4 then --current nested table format

-		--wip: this is a filthy hack that works surprisingly well

-		value = value:gsub("return%s*{", "", 1):gsub("}%s*$", "", 1)

-		local escaped = value:gsub("\\\\", "@@"):gsub("\\\"", "@@"):gsub("(\"[^\"]*\")", function(s) return string.rep("@", #s) end)

-		local startpos, startpos1, endpos = 1, 1

-		local nodes = {}

-		while true do

-			startpos, endpos = escaped:find("},%s*{", startpos)

-			if not startpos then

-				break

+	elseif version == 4 or version == 5 then -- Nested table format

+		if not jit then

+			-- This is broken for larger tables in the current version of LuaJIT

+			nodes = minetest.deserialize(content)

+		else

+			-- XXX: This is a filthy hack that works surprisingly well

+			nodes = {}

+			value = value:gsub("return%s*{", "", 1):gsub("}%s*$", "", 1)

+			local escaped = value:gsub("\\\\", "@@"):gsub("\\\"", "@@"):gsub("(\"[^\"]*\")", function(s) return string.rep("@", #s) end)

+			local startpos, startpos1, endpos = 1, 1

+			while true do

+				startpos, endpos = escaped:find("},%s*{", startpos)

+				if not startpos then

+					break

+				end

+				local current = value:sub(startpos1, startpos)

+				table.insert(nodes, minetest.deserialize("return " .. current))

+				startpos, startpos1 = endpos, endpos

 			end

-			local current = value:sub(startpos1, startpos)

-			table.insert(nodes, minetest.deserialize("return " .. current))

-			startpos, startpos1 = endpos, endpos

+			table.insert(nodes, minetest.deserialize("return " .. value:sub(startpos1)))

 		end

-		table.insert(nodes, minetest.deserialize("return " .. value:sub(startpos1)))

+	else

+		return nil

+	end

+	return nodes

+end

+

+--- Determines the volume the nodes represented by string `value` would occupy

+-- if deserialized at `origin_pos`.

+-- @return Low corner position.

+-- @return High corner position.

+-- @return The number of nodes.

+worldedit.allocate = function(origin_pos, value)

+	local nodes = worldedit.load_schematic(value)

+	if not nodes then return nil end

+	return worldedit.allocate_with_nodes(origin_pos, nodes)

+end

 

-		--local nodes = minetest.deserialize(value) --wip: this is broken for larger tables in the current version of LuaJIT

 

-		count = #nodes

-		for index = 1, count do

-			local entry = nodes[index]

-			x, y, z = originx + entry.x, originy + entry.y, originz + entry.z

-			if x < pos1x then pos1x = x end

-			if y < pos1y then pos1y = y end

-			if z < pos1z then pos1z = z end

-			if x > pos2x then pos2x = x end

-			if y > pos2y then pos2y = y end

-			if z > pos2z then pos2z = z end

-		end

+-- Internal

+worldedit.allocate_with_nodes = function(origin_pos, nodes)

+	local huge = math.huge

+	local pos1x, pos1y, pos1z = huge, huge, huge

+	local pos2x, pos2y, pos2z = -huge, -huge, -huge

+	local origin_x, origin_y, origin_z = origin_pos.x, origin_pos.y, origin_pos.z

+	for i, entry in ipairs(nodes) do

+		x, y, z = origin_x + entry.x, origin_y + entry.y, origin_z + entry.z

+		if x < pos1x then pos1x = x end

+		if y < pos1y then pos1y = y end

+		if z < pos1z then pos1z = z end

+		if x > pos2x then pos2x = x end

+		if y > pos2y then pos2y = y end

+		if z > pos2z then pos2z = z end

 	end

 	local pos1 = {x=pos1x, y=pos1y, z=pos1z}

 	local pos2 = {x=pos2x, y=pos2y, z=pos2z}

-	return pos1, pos2, count

+	return pos1, pos2, #nodes

 end

 

---loads the nodes represented by string `value` at position `originpos`, returning the number of nodes deserialized

---contains code based on [table.save/table.load](http://lua-users.org/wiki/SaveTableToFile) by ChillCode, available under the MIT license (GPL compatible)

-worldedit.deserialize = function(originpos, value)

-	--make area stay loaded

-	local pos1, pos2 = worldedit.allocate(originpos, value)

+

+--- Loads the nodes represented by string `value` at position `origin_pos`.

+-- @return The number of nodes deserialized.

+worldedit.deserialize = function(origin_pos, value)

+	local nodes = worldedit.load_schematic(value)

+	if not nodes then return nil end

+

+	-- Make area stay loaded

+	local pos1, pos2 = worldedit.allocate_with_nodes(origin_pos, nodes)

 	local manip = minetest.get_voxel_manip()

 	manip:read_from_map(pos1, pos2)

 

-	local originx, originy, originz = originpos.x, originpos.y, originpos.z

+	local origin_x, origin_y, origin_z = origin_pos.x, origin_pos.y, origin_pos.z

 	local count = 0

 	local add_node, get_meta = minetest.add_node, minetest.get_meta

-	local version = worldedit.valueversion(value)

-	if version == 1 or version == 2 then --original flat table format

-		--obtain the node table

-		local get_tables = loadstring(value)

-		if not get_tables then --error loading value

-			return count

-		end

-		local tables = get_tables()

-

-		--transform the node table into an array of nodes

-		for i = 1, #tables do

-			for j, v in pairs(tables[i]) do

-				if type(v) == "table" then

-					tables[i][j] = tables[v[1]]

-				end

-			end

-		end

-		local nodes = tables[1]

-

-		--load the node array

-		count = #nodes

-		if version == 1 then --original flat table format

-			for index = 1, count do

-				local entry = nodes[index]

-				local pos = entry[1]

-				pos.x, pos.y, pos.z = originx - pos.x, originy - pos.y, originz - pos.z

-				add_node(pos, entry[2])

-			end

-		else --previous meta flat table format

-			for index = 1, #nodes do

-				local entry = nodes[index]

-				entry.x, entry.y, entry.z = originx + entry.x, originy + entry.y, originz + entry.z

-				add_node(entry, entry) --entry acts both as position and as node

-				get_meta(entry):from_table(entry.meta)

-			end

-		end

-	elseif version == 3 then --previous list format

-		local pos = {x=0, y=0, z=0}

-		local node = {name="", param1=0, param2=0}

-		for x, y, z, name, param1, param2 in value:gmatch("([+-]?%d+)%s+([+-]?%d+)%s+([+-]?%d+)%s+([^%s]+)%s+(%d+)%s+(%d+)[^\r\n]*[\r\n]*") do --match node entries

-			pos.x, pos.y, pos.z = originx + tonumber(x), originy + tonumber(y), originz + tonumber(z)

-			node.name, node.param1, node.param2 = name, param1, param2

-			add_node(pos, node)

-			count = count + 1

-		end

-	elseif version == 4 then --current nested table format

-		--wip: this is a filthy hack that works surprisingly well

-		value = value:gsub("return%s*{", "", 1):gsub("}%s*$", "", 1)

-		local escaped = value:gsub("\\\\", "@@"):gsub("\\\"", "@@"):gsub("(\"[^\"]*\")", function(s) return string.rep("@", #s) end)

-		local startpos, startpos1, endpos = 1, 1

-		local nodes = {}

-		while true do

-			startpos, endpos = escaped:find("},%s*{", startpos)

-			if not startpos then

-				break

-			end

-			local current = value:sub(startpos1, startpos)

-			table.insert(nodes, minetest.deserialize("return " .. current))

-			startpos, startpos1 = endpos, endpos

-		end

-		table.insert(nodes, minetest.deserialize("return " .. value:sub(startpos1)))

-

-		--local nodes = minetest.deserialize(value) --wip: this is broken for larger tables in the current version of LuaJIT

-

-		--load the nodes

-		count = #nodes

-		for index = 1, count do

-			local entry = nodes[index]

-			entry.x, entry.y, entry.z = originx + entry.x, originy + entry.y, originz + entry.z

-			add_node(entry, entry) --entry acts both as position and as node

-		end

-

-		--load the metadata

-		for index = 1, count do

-			local entry = nodes[index]

+	for i, entry in ipairs(nodes) do

+		entry.x, entry.y, entry.z = origin_x + entry.x, origin_y + entry.y, origin_z + entry.z

+		-- Entry acts as both position and node

+		add_node(entry, entry)

+		if entry.meta then

 			get_meta(entry):from_table(entry.meta)

 		end

 	end

-	return count

+	return #nodes

 end

+

diff --git a/worldedit_commands/init.lua b/worldedit_commands/init.lua
index 7d347c9..93e594a 100644
--- a/worldedit_commands/init.lua
+++ b/worldedit_commands/init.lua
@@ -911,9 +911,12 @@ minetest.register_chatcommand("/allocate", {
 		local value = file:read("*a")

 		file:close()

 

-		if worldedit.valueversion(value) == 0 then --unknown version

-			worldedit.player_notify(name, "invalid file: file is invalid or created with newer version of WorldEdit")

+		local version = worldedit.read_header(value)

+		if version == 0 then

+			worldedit.player_notify(name, "File is invalid!")

 			return

+		elseif version > worldedit.LATEST_SERIALIZATION_VERSION then

+			worldedit.player_notify(name, "File was created with newer version of WorldEdit!")

 		end

 		local nodepos1, nodepos2, count = worldedit.allocate(pos, value)

 

@@ -963,8 +966,12 @@ minetest.register_chatcommand("/load", {
 		local value = file:read("*a")

 		file:close()

 

-		if worldedit.valueversion(value) == 0 then --unknown version

-			worldedit.player_notify(name, "invalid file: file is invalid or created with newer version of WorldEdit")

+		local version = worldedit.read_header(value)

+		if version == 0 then

+			worldedit.player_notify(name, "File is invalid!")

+			return

+		elseif version > worldedit.LATEST_SERIALIZATION_VERSION then

+			worldedit.player_notify(name, "File was created with newer version of WorldEdit!")

 			return

 		end