pingbird · August 22, 2024 16:25 · Aug 31, 2015 · Aug 31, 2015
diff --git a/nbt.lua b/nbt.lua
@@ -2,6 +2,8 @@
     Lua NBT encoding and decoding by PixelToast, public domain
     example output (serialized) from a player.dat: http://hastebin.com/kogupimizi.txt
     requires string.pack/string.unpack
+    
+    note: nbt is usually gzipped, you must inflate it before decoding
 ]]
 
 nbt={}

diff --git a/nbt.lua b/nbt.lua
@@ -0,0 +1,175 @@
+--[[
+    Lua NBT encoding and decoding by PixelToast, public domain
+    example output (serialized) from a player.dat: http://hastebin.com/kogupimizi.txt
+    requires string.pack/string.unpack
+]]
+
+nbt={}
+
+local readTag
+local tagname={
+	[0]="end",
+	"byte",
+	"short",
+	"int",
+	"long",
+	"float",
+	"double",
+	"byte array",
+	"string",
+	"list",
+	"compound",
+	"int array",
+}
+local tagid={
+	["end"]=0,
+	["byte"]=1,
+	["short"]=2,
+	["int"]=3,
+	["long"]=4,
+	["float"]=5,
+	["double"]=6,
+	["byte array"]=7,
+	["string"]=8,
+	["list"]=9,
+	["compound"]=10,
+	["int array"]=11,
+}
+function readTag(txt,id)
+	local function readData(fmt)
+		local o=string.unpack(fmt,txt)
+		txt=txt:sub(string.packsize(fmt)+1)
+		return o
+	end
+	local name
+	if not id then
+		id=readData(">b")
+		if id==0 then
+			return txt,{type="end"}
+		end
+		local nmlen=readData(">H")
+		name=txt:sub(1,nmlen)
+		txt=txt:sub(nmlen+1)
+	end
+	local out={type=tagname[id] or "corrupt",name=name}
+	if id==1 then
+		out.value=readData(">b")
+	elseif id==2 then
+		out.value=readData(">h")
+	elseif id==3 then
+		out.value=readData(">i4")
+	elseif id==4 then
+		out.value=readData(">i8")
+	elseif id==5 then
+		out.value=readData(">f")
+	elseif id==6 then
+		out.value=readData(">d")
+	elseif id==7 then
+		local size=readData(">i4")
+		local o={}
+		for l1=1,size do
+			table.insert(o,readData(">b"))
+		end
+		out.values=o
+	elseif id==8 then
+		local len=readData(">h")
+		local o=txt:sub(1,len)
+		txt=txt:sub(len+1)
+		out.value=o
+	elseif id==9 then
+		local tagid=readData(">b")
+		local size=readData(">i4")
+		local o={}
+		for l1=1,size do
+			local ot
+			txt,ot=readTag(txt,tagid)
+			table.insert(o,ot)
+		end
+		out.values=o
+		out.types=tagname[tagid]
+	elseif id==10 then
+		local o={}
+		while true do
+			local ot
+			txt,ot=readTag(txt)
+			if ot.type=="end" then
+				break
+			end
+			table.insert(o,ot)
+		end
+		out.values=o
+	elseif id==11 then
+		local size=readData(">i4")
+		local o={}
+		for l1=1,size do
+			table.insert(o,readData(">i4"))
+		end
+		out.values=o
+	end
+	return txt,out
+end
+
+local writeTag
+function writeTag(v,raw)
+	print("writing "..serialize(v))
+	local o=""
+	if not raw then
+		o=o..string.pack(">b",tagid[v.type])
+		if v.type~="end" then
+			local name=v.name or ""
+			o=o..string.pack(">H",#name)..name
+		end
+	end
+	if v.type=="end" then
+		return o.."\0"
+	elseif v.type=="byte" then
+		return o..string.pack(">b",v.value)
+	elseif v.type=="short" then
+		return o..string.pack(">h",v.value)
+	elseif v.type=="int" then
+		return o..string.pack(">i4",v.value)
+	elseif v.type=="long" then
+		return o..string.pack(">i8",v.value)
+	elseif v.type=="float" then
+		return o..string.pack(">f",v.value)
+	elseif v.type=="double" then
+		return o..string.pack(">d",v.value)
+	elseif v.type=="byte array" then
+		o=o..string.pack(">i4",#v.values)
+		for l1=1,#v.values do
+			o=o..string.pack(">b",v.values[l1])
+		end
+		return o
+	elseif v.type=="string" then
+		return o..string.pack(">H",#v.value)..v.value
+	elseif v.type=="list" then
+		o=o..string.pack(">b",tagid[v.types])
+		o=o..string.pack(">i4",#v.values)
+		for l1=1,#v.values do
+			o=o..writeTag(v.values[l1],true)
+		end
+		return o
+	elseif v.type=="compound" then
+		for l1=1,#v.values do
+			o=o..writeTag(v.values[l1])
+		end
+		return o.."\0"
+	elseif v.type=="int array" then
+		o=o..string.pack(">i4",#v.values)
+		for l1=1,#v.values do
+			o=o..string.pack(">i4",v.values[l1])
+		end
+		return o
+	end
+	return ""
+end
+
+function nbt.decode(txt)
+	local o
+	txt,o=readTag(txt)
+	return o
+end
+
+function nbt.encode(t)
+	return writeTag(t)
+end