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Event Loop

In computer science, the event loop, message dispatcher, message loop, message pump, or run loop is a programming construct that waits for and dispatches events or messages in a program.

It works by making a request to some internal or external "event provider" (that generally blocks the request until an event has arrived), and then it calls the relevant event handler ("dispatches the event").

The event-loop may be used in conjunction with a reactor, if the event provider follows the file interface, which can be selected or 'polled' (the Unix system call, not actual polling).

The event loop almost always operates asynchronously with the message originator.

原文：架构师之路

58速运货物运输，滴滴快递网约车，司机端都是按照行驶公里数收费的，所以“里程”的准确性，是这类业务的一个核心难题，“里程计算”方案演进，以及其中优化思想，是本文要讨论的问题

一、直接调用地图API

这是最容易想到的方法，最省事，但司机往往不是按照预定的路线行驶的，很有可能因为堵车、道路封闭等改变路线，所以直接调用地图API，一次性计算出一个预估值，不太靠谱

优化方案：根据实际路线计算里程

	local function createReadBuffer(data)
	local index = 1

	local function readRaw(byteCount)
	local startIndex = index
	index = index + byteCount
	local endIndex = index - 1
	return string.byte(data, startIndex, endIndex)
	end

	#include <WebServer.h>
	#include <WiFi.h>
	#include <WiFiUdp.h>

	// the IP of the machine to which you send msgs - this should be the correct IP in most cases (see note in python code)
	#define CONSOLE_IP "192.168.1.2"
	#define CONSOLE_PORT 4210
	const char* ssid = "ESP32";
	const char* password = "12345678";
	WiFiUDP Udp;

	/*
	Application:
	- Interface water flow sensor with ESP32 board.

	Board:
	- ESP32 Dev Module
	https://my.cytron.io/p-node32-lite-wifi-and-bluetooth-development-kit

	Sensor:
	- G 1/2 Water Flow Sensor

	/*
	* Server.cpp
	*
	* EventServer is a simple C++ TCP socket server implementation,
	* to serve as an example to anyone who wants to learn it.
	* It can interface with the rest of your program using three callback functions.
	* - onConnect, which fires when a new client connects. the client's fd is passed.
	* - onDisconnect, which fires when a client disconnects. passes fd.
	* - onInput, fires when input is received from a client. passes fd and char*
	*

	#include <iostream>
	#include <map>
	#include <algorithm>
	#include <functional>
	#include <memory>

	using namespace std;

	/***
	* A base class for event arguments

	.ATmega328
	; Ida avr.cfg (c) THANATOS

	SUBARCH=5

	RAM=2048
	ROM=32768
	EEPROM=1024

	; MEMORY MAP

	// This function is based on the code found at (the original source doesn't work well)
	// http://stackoverflow.com/questions/20774648/three-js-generate-uv-coordinate
	//
	// She following page explains how UV map should be calculated
	// https://solutiondesign.com/blog/-/blogs/webgl-and-three-js-texture-mappi-1/
	//
	// The following documentation shows what a apherical UV map should look like
	// https://threejs.org/examples/#misc_uv_tests

	var ThreeUvMapper = {

	var outline_shader = {
	uniforms: {
	"linewidth": { type: "f", value: 0.3 },
	},
	vertex_shader: [
	"uniform float linewidth;",
	"void main() {",
	"vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );",
	"vec4 displacement = vec4( normalize( normalMatrix * normal ) * linewidth, 0.0 ) + mvPosition;",
	"gl_Position = projectionMatrix * displacement;",