chore: refractor

ServerScriptService/Actor/ServerChunkManager/TerrainGen/Deflate/Huffman/PriorityQueue.lua

@@ -0,0 +1,232 @@
+--[[
+
+ PriorityQueue - v1.0.1 - public domain Lua priority queue
+ implemented with indirect binary heap
+ no warranty implied; use at your own risk
+
+ based on binaryheap library (github.com/iskolbin/binaryheap)
+
+ author: Ilya Kolbin (iskolbin@gmail.com)
+ url: github.com/iskolbin/priorityqueue
+
+ See documentation in README file.
+
+ COMPATIBILITY
+
+ Lua 5.1, 5.2, 5.3, LuaJIT 1, 2
+
+ LICENSE
+
+ This software is dual-licensed to the public domain and under the following
+ license: you are granted a perpetual, irrevocable license to copy, modify,
+ publish, and distribute this file as you see fit.
+
+--]]
+
+local floor, setmetatable = math.floor, setmetatable
+
+local function siftup( self, from )
+	local items, priorities, indices, higherpriority = self, self._priorities, self._indices, self._higherpriority
+	local index = from
+	local parent = floor( index / 2 )
+	while index > 1 and higherpriority( priorities[index], priorities[parent] ) do
+		priorities[index], priorities[parent] = priorities[parent], priorities[index]
+		items[index], items[parent] = items[parent], items[index]
+		indices[items[index]], indices[items[parent]] = index, parent
+		index = parent
+		parent = floor( index / 2 )
+	end
+	return index
+end
+
+local function siftdown( self, limit )
+	local items, priorities, indices, higherpriority, size = self, self._priorities, self._indices, self._higherpriority, self._size
+	for index = limit, 1, -1 do
+		local left = index + index
+		local right = left + 1
+		while left <= size do
+			local smaller = left
+			if right <= size and higherpriority( priorities[right], priorities[left] ) then
+				smaller = right
+			end
+			if higherpriority( priorities[smaller], priorities[index] ) then
+				items[index], items[smaller] = items[smaller], items[index]
+				priorities[index], priorities[smaller] = priorities[smaller], priorities[index]
+				indices[items[index]], indices[items[smaller]] = index, smaller
+			else
+				break
+			end
+			index = smaller
+			left = index + index
+			right = left + 1
+		end
+	end
+end
+
+local PriorityQueueMt
+
+local PriorityQueue = {}
+
+local function minishigher( a, b )
+	return a < b
+end
+
+local function maxishigher( a, b )
+	return a > b
+end
+
+function PriorityQueue.new( priority_or_array )
+	local t = type( priority_or_array )
+	local higherpriority = minishigher
+
+	if t == 'table' then
+		higherpriority = priority_or_array.higherpriority or higherpriority
+	elseif t == 'function' or t == 'string' then
+		higherpriority = priority_or_array
+	elseif t ~= 'nil' then
+		local msg = 'Wrong argument type to PriorityQueue.new, it must be table or function or string, has: %q'
+		error( msg:format( t ))
+	end
+
+	if type( higherpriority ) == 'string' then
+		if higherpriority == 'min' then
+			higherpriority = minishigher
+		elseif higherpriority == 'max' then
+			higherpriority = maxishigher
+		else
+			local msg = 'Wrong string argument to PriorityQueue.new, it must be "min" or "max", has: %q'
+			error( msg:format( tostring( higherpriority )))
+		end
+	end
+
+	local self = setmetatable( {
+		_priorities = {},
+		_indices = {},
+		_size = 0,
+		_higherpriority = higherpriority or minishigher
+	}, PriorityQueueMt )
+
+	if t == 'table' then
+		self:batchenq( priority_or_array )
+	end
+
+	return self
+end
+
+function PriorityQueue:enqueue( item, priority )
+	local items, priorities, indices = self, self._priorities, self._indices
+	if indices[item] ~= nil then
+		error( 'Item ' .. tostring(indices[item]) .. ' is already in the heap' )
+	end
+	local size = self._size + 1
+	self._size = size	
+	items[size], priorities[size], indices[item] = item, priority, size
+	siftup( self, size ) 
+	return self
+end
+
+function PriorityQueue:remove( item )
+	local index = self._indices[item]
+	if index ~= nil then
+		local size = self._size
+		local items, priorities, indices = self, self._priorities, self._indices
+		indices[item] = nil
+		if size == index then
+			items[size], priorities[size] = nil, nil
+			self._size = size - 1
+		else
+			local lastitem = items[size]
+			items[index], priorities[index] = items[size], priorities[size]
+			items[size], priorities[size] = nil, nil
+			indices[lastitem] = index
+			size = size - 1
+			self._size = size
+			if size > 1 then
+				siftdown( self, siftup( self, index )) 
+			end
+		end
+		return true
+	else
+		return false
+	end
+end
+
+function PriorityQueue:contains( item )
+	return self._indices[item] ~= nil
+end
+
+function PriorityQueue:update( item, priority )
+	local ok = self:remove( item )
+	if ok then
+		self:enqueue( item, priority )
+		return true
+	else
+		return false
+	end
+end
+
+function PriorityQueue:dequeue()
+	local size = self._size
+
+	assert( size > 0, 'Heap is empty' )
+
+	local items, priorities, indices = self, self._priorities, self._indices
+	local item, priority = items[1], priorities[1]
+	indices[item] = nil
+
+	if size > 1 then
+		local newitem = items[size]
+		items[1], priorities[1] = newitem, priorities[size]
+		items[size], priorities[size] = nil, nil
+		indices[newitem] = 1
+		size = size - 1
+		self._size = size
+		siftdown( self, 1 )
+	else
+		items[1], priorities[1] = nil, nil
+		self._size = 0
+	end
+
+	return item, priority
+end
+
+function PriorityQueue:peek()
+	return self[1], self._priorities[1]
+end
+
+function PriorityQueue:len()
+	return self._size
+end
+
+function PriorityQueue:empty()
+	return self._size <= 0
+end
+
+function PriorityQueue:batchenq( iparray )
+	local items, priorities, indices = self, self._priorities, self._indices
+	local size = self._size
+	for i = 1, #iparray, 2 do
+		local item, priority = iparray[i], iparray[i+1]
+		if indices[item] ~= nil then
+			error( 'Item ' .. tostring(indices[item]) .. ' is already in the heap' )
+		end
+		size = size + 1
+		items[size], priorities[size] = item, priority
+		indices[item] = size
+	end
+	self._size = size
+	if size > 1 then
+		siftdown( self, floor( size / 2 ))
+	end
+end
+
+PriorityQueueMt = {
+	__index = PriorityQueue,
+	__len = PriorityQueue.len,
+}
+
+return setmetatable( PriorityQueue, {
+	__call = function( _, ... )
+		return PriorityQueue.new( ... )
+	end
+} )