chore: refractor

ServerScriptService/Actor/ServerChunkManager/TerrainGen/Deflate/LZW.lua

@@ -0,0 +1,170 @@
+-- Module by 1waffle1 and boatbomber, optimized and fixed by iiau
+-- https://devforum.roblox.com/t/text-compression/163637/37
+
+local dictionary = {} -- key to len
+
+do -- populate dictionary
+	local length = 0
+	for i = 32, 127 do
+		if i ~= 34 and i ~= 92 then
+			local c = string.char(i)
+			dictionary[c] = length
+			dictionary[length] = c
+			length = length + 1
+		end
+	end
+end
+
+local escapemap_126, escapemap_127 = {}, {}
+local unescapemap_126, unescapemap_127 = {}, {}
+
+local blacklisted_126 = { 34, 92 }
+for i = 126, 180 do
+	table.insert(blacklisted_126, i)
+end
+
+do -- Populate escape map
+	-- represents the numbers 0-31, 34, 92, 126, 127 (36 characters)
+	-- and 128-180 (52 characters)
+	-- https://devforum.roblox.com/t/text-compression/163637/5
+	for i = 0, 31 + #blacklisted_126 do
+		local b = blacklisted_126[i - 31]
+		local s = i + 32
+
+		-- Note: 126 and 127 are magic numbers
+		local c = string.char(b or i)
+		local e = string.char(s + (s >= 34 and 1 or 0) + (s >= 91 and 1 or 0))
+
+		escapemap_126[c] = e
+		unescapemap_126[e] = c
+	end
+
+	for i = 1, 255 - 180 do
+		local c = string.char(i + 180)
+		local s = i + 34
+		local e = string.char(s + (s >= 92 and 1 or 0))
+
+		escapemap_127[c] = e
+		unescapemap_127[e] = c
+	end
+end
+
+local function escape(s)
+	-- escape the control characters 0-31, double quote 34, backslash 92, Tilde 126, and DEL 127 (36 chars)
+	-- escape characters 128-180 (53 chars)
+	return string.gsub(string.gsub(s, '[%c"\\\126-\180]', function(c)
+		return "\126" .. escapemap_126[c]
+	end), '[\181-\255]', function(c)
+		return "\127" .. escapemap_127[c]
+	end)
+end
+local function unescape(s)
+	return string.gsub(string.gsub(s, "\127(.)", function(e)
+		return unescapemap_127[e]
+	end), "\126(.)", function(e)
+		return unescapemap_126[e]
+	end)
+end
+
+local b93Cache = {}
+local function tobase93(n)
+	local value = b93Cache[n]
+	if value then
+		return value
+	end
+
+	local c = n
+	value = ""
+	repeat
+		local remainder = n % 93
+		value = dictionary[remainder] .. value
+		n = (n - remainder) / 93
+	until n == 0
+
+	b93Cache[c] = value
+	return value
+end
+
+local b10Cache = {}
+local function tobase10(value)
+	local n = b10Cache[value]
+	if n then
+		return n
+	end
+
+	n = 0
+	for i = 1, #value do
+		n = n + math.pow(93, i - 1) * dictionary[string.sub(value, -i, -i)]
+	end
+
+	b10Cache[value] = n
+	return n
+end
+
+local function compress(text)
+	assert(type(text) == "string", "bad argument #1 to 'compress' (string expected, got " .. typeof(text) .. ")")
+	local dictionaryCopy = table.clone(dictionary)
+	local key, sequence, size = "", {}, #dictionary
+
+	local width, spans, span = 1, {}, 0
+	local function listkey(k)
+		local value = tobase93(dictionaryCopy[k])
+		local valueLength = #value
+		if valueLength > width then
+			width, span, spans[width] = valueLength, 0, span
+		end
+		table.insert(sequence, string.rep(" ", width - valueLength) .. value)
+		span += 1
+	end
+	text = escape(text)
+	for i = 1, #text do
+		local c = string.sub(text, i, i)
+		local new = key .. c
+		if dictionaryCopy[new] then
+			key = new
+		else
+			listkey(key)
+			key = c
+			size += 1
+			dictionaryCopy[new] = size
+			dictionaryCopy[size] = new
+		end
+	end
+	listkey(key)
+	spans[width] = span
+	return table.concat(spans, ",") .. "|" .. table.concat(sequence)
+end
+
+local function decompress(text)
+	assert(type(text) == "string", "bad argument #1 to 'decompress' (string expected, got " .. typeof(text) .. ")")
+	local dictionaryCopy = table.clone(dictionary)
+	local sequence, spans, content = {}, string.match(text, "(.-)|(.*)")
+	local groups, start = {}, 1
+	for span in string.gmatch(spans, "%d+") do
+		local width = #groups + 1
+		groups[width] = string.sub(content, start, start + span * width - 1)
+		start = start + span * width
+	end
+	local previous
+
+	for width, group in ipairs(groups) do
+		for value in string.gmatch(group, string.rep(".", width)) do
+			local entry = dictionaryCopy[tobase10(value)]
+			if previous then
+				if entry then
+					table.insert(dictionaryCopy, previous .. string.sub(entry, 1, 1))
+				else
+					entry = previous .. string.sub(previous, 1, 1)
+					table.insert(dictionaryCopy, entry)
+				end
+				table.insert(sequence, entry)
+			else
+				sequence[1] = entry
+			end
+			previous = entry
+		end
+	end
+	return unescape(table.concat(sequence))
+end
+
+return { compress = compress, decompress = decompress }