File

util/throttle.lua @ 12714:82bca7191f13

util.crypto: Use stack space buffers Removes assumption that LUAL_BUFFERSIZE is known at pre-processing time, which it is not in Lua 5.3 and 5.4, where it is a computed macro based on sizeof. Allocation of stack space is safer and faster, no need to worry about luaL_prepbuffer failing to allocate memory and skipping free()
author Kim Alvefur <zash@zash.se>
date Mon, 11 Jul 2022 17:01:55 +0200
parent 8555:4f0f5b49bb03
child 12975:d10957394a3c
line wrap: on
line source


local gettime = require "util.time".now
local setmetatable = setmetatable;

local _ENV = nil;
-- luacheck: std none

local throttle = {};
local throttle_mt = { __index = throttle };

function throttle:update()
	local newt = gettime();
	local elapsed = newt - self.t;
	self.t = newt;
	local balance = (self.rate * elapsed) + self.balance;
	if balance > self.max then
		self.balance = self.max;
	else
		self.balance = balance;
	end
	return self.balance;
end

function throttle:peek(cost)
	cost = cost or 1;
	return self.balance >= cost or self:update() >= cost;
end

function throttle:poll(cost, split)
	if self:peek(cost) then
		self.balance = self.balance - cost;
		return true;
	else
		local balance = self.balance;
		if split then
			self.balance = 0;
		end
		return false, balance, (cost-balance);
	end
end

local function create(max, period)
	return setmetatable({ rate = max / period, max = max, t = gettime(), balance = max }, throttle_mt);
end

return {
	create = create;
};