init project by WifiLightController

.vscode/settings.json

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+{
+    "Lua.diagnostics.globals": [
+        "wifi",
+        "net",
+        "u8g2",
+        "i2c",
+        "gpio",
+        "enduser_setup",
+        "file",
+        "tmr"
+    ]
+}

LICENSE

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+MIT License
+
+Copyright (c) 2023 jkpete
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

OldCode/AutoWifi.lua

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+--tips to user link-AP
+function PageAPNet()
+    Disp:clearBuffer()
+    --Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:drawStr(0,10,"AP-LinkMode");
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(0,26,"Please use your");
+    Disp:drawStr(0,36,"mobile phone search");
+    Disp:drawStr(0,46,"and link ap-point");
+    Disp:drawStr(0,56,"DY-Light-Controller");
+    Disp:updateDisplay();
+end
+--mobile setting ap and passwd
+function AutoLinkByMobile()
+    wifi.sta.clearconfig();
+    wifi.setmode(wifi.STATIONAP);
+    wifi.ap.config({ssid="DY-Light-Controller", auth=wifi.OPEN});
+    enduser_setup.manual(true);
+    enduser_setup.start(
+        "DY-Light-Controller",
+        function()
+            print("Connected to WiFi!")
+        end,
+        function(err, str)
+            print("enduser_setup: Err #" .. err .. ": " .. str)
+        end
+    )
+    print("init endUserServer")
+end

README.md

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+# CarController
+
+---
+
+基于NodeMcu开发的ESP8266智能小车控制器，接入SSD1306作为配网以及服务显示功能，后续会增加更多功能
+
+# 1.准备工作🧐
+
+---
+
+## 1.1设备清单
+
+`数据线等烧录用不在此列`
+
+| 设备名称        | 数量     | 设备型号                  |
+| ----------- | ------ | --------------------- |
+| ESP8266     | 1      | ESP-12F，其他ESP8266可用型号 |
+| led灯珠       | 4-5个   | 3v3最低耐压               |
+| 电线          | 12-16条 | 常用杜邦线或者其他相似参数         |
+| I2C协议OLED屏幕 | 1      | SSD1306_12864_noname  |
+| USB供电（可选）   | 1      | 3.3v引脚供电&5VUSB供电      |
+
+## 1.2固件烧录
+
+先从该连接，下载 Flash下载工具(flash_download_tool_3.9.5_0.zip)，如果有新版本可能名称会有所不同。
+
+  [工具 | 乐鑫科技 ](https://www.espressif.com.cn/zh-hans/support/download/other-tools)
+
+下载完之后，将工程下的flash_download_tool_3.9.5.exe打开
+![](DocRes\1_1.jpg)
+
+选择ESP8266
+
+![](DocRes\1_2.jpg)
+
+进入如下界面，点击第一项，选择工程下 Firmware里对应的固件文件，由于程序使用的固件版本为float，但未曾写过使用float类型的程序。int没有测试过，保险起见可以选择float版本，右边填0。选择如下所示，串口检测到后点击对应的串口进行烧录即可。
+
+![](DocRes/1_0.jpg)
+
+烧录的波特率默认为115200，运行以及开发用的波特率同理。
+
+## 1.3程序烧录
+
+首先去github上下载ESPlorer，右侧release可以下载最新的发布版本，可能需要翻墙。
+
+[ESPlorer](https://github.com/4refr0nt/ESPlorer)
+
+下载完成后运行ESPlorer.bat，即可打开该开发工具，然后打开工程的所有lua文件并保存到ESP8266中。目前还处于手动配置网络的阶段，后续会继续优化该配网功能。
+
+拷贝 **Src** 文件夹下的所有脚本文件到ESP8266中。
+
+![](DocRes/InstallSoft.png)
+
+# 2.接线说明🔌
+
+---
+
+NodeMCU开发板引脚图
+
+![](DocRes/NodeMcu_Pinout.webp)
+
+## 2.1 GPIO-LED接线说明
+
+GPIO控制D0-D2，一共三路GPIO供电开关，引出脚需要接入二极管以防止干扰其他控制器工作。
+
+| 接线方式 | LED引脚 | ESP8266引脚 |
+| ---- | ----- | --------- |
+| 直连   | 负极    | GND       |
+| 直连   | 正极    | D0        |
+| 直连   | 正极    | D1        |
+| 直连   | 正极    | D2        |
+
+## 2.2 SSD1306-12864-I2C接线说明
+
+oled显示屏用于显示配网参数以及连接状态，指示灯状态等信息，方便更快找到设备故障原因。
+
+| 接线方式 | SSD1306-12864-I2C引脚 | ESP8266引脚 |
+| ---- | ------------------- | --------- |
+| 直连   | GND                 | GND       |
+| 直连   | VCC                 | 3v3       |
+| 直连   | SCL                 | D6        |
+| 直连   | SDA                 | D5        |
+
+`如有其他设备需要接线后续补充`
+
+# 3.串口软件网络设置⚙
+
+---
+
+串口软件下载地址[点击下载](https://pan.baidu.com/s/15V7FfWHhwIFyYaKDJv0Rig)
+提取码：Node 
+
+打开串口软件，NodeMCUSerialTools文件夹下面的NetTools.exe。
+
+以下操作开始之前，请先按照第一步烧录完固件与软件。
+
+ESP8266+数据线与PC进行链接。
+
+或者使用ESP8266+CH340等串口连接设备与PC进行链接
+
+（TX-RX，RX-TX）
+
+![](DocRes/1_3.jpg)
+
+## 3.1选择串口
+
+如果是连接之前打开，可以先检查右下角COM串口列表，连接设备后点击刷新，可以看到新的串口设备在列表中新增。
+
+点击右下角以刷新或者是切换串口设备。
+
+## 3.2设置WiFi连接信息
+
+选项说明
+
+| 名称     | 含义              |
+| ------ | --------------- |
+| SSID名称 | 手机扫描热点显示的WiFi名称 |
+| 密码     | 该热点的WiFi密码      |
+
+写入配网信息
+
+等待2-3秒后，软件会通过串口写入WiFi连接的信息。
+
+如果是首次配网，会自动连接网络。
+
+如果是第二次配网，需要重启并验证网络。
+
+## 3.3设置设备的IP地址
+
+![](DocRes/1_4.png)
+
+选项说明
+
+| 名称   | 含义                                                                                      |
+| ---- | --------------------------------------------------------------------------------------- |
+| IP地址 | 跟据平板的网段ip地址，配置好对应网段的地址（如：平板IP地址：192.168.6.15，则该地址只能配置为192.168.6.x，x为2-255之间除了15的任意一个数字） |
+| 子网掩码 | 255.255.255.0（默认值，一般不需要修改）                                                              |
+| 默认网关 | 如果平板网段地址为192.168.6.15，一般情况下网关为192.168.6.1，可以用电脑的cmd->ipconfig来查看相应的网关地址。                |
+
+# 4.通讯协议📡
+
+该设备使用UDP作为通讯协议，UDP地址为上面配置的ip地址，端口号默认为6000。

SaveData/Config.lua

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+Config_Table = {
+    ["IpAddress"]="192.168.1.210",
+    ["Gateway"]="192.168.1.1",
+    ["Version"]="V0.1",
+    ["Netmask"]="255.255.255.0"
+}

SaveData/eus_params.lua

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+

Src/EasySave.lua

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+Files = file.list();
+if Files["Config.lua"] then
+    dofile("Config.lua");
+end
+--Get data from config files
+function GetData(key)
+    if Config_Table[key] ~=nil then
+        return Config_Table[key];
+    end
+    return nil;
+end
+
+--Save data to config files
+function SaveData(key,value)
+    file.open("Config.lua", "w+");
+    Config_Table[key] = value;
+    local tableStr = TableToStr(Config_Table);
+    file.write(tableStr);
+    file.close();
+    --print(key.."-"..value.."has been Saved");
+end
+
+function TableToStr(table)
+    local stringData = "{\n"
+    for key, value in pairs(table) do
+        local keyValue = "[\"" .. tostring(key) .. "\"]="
+        local valueString = "\"" .. tostring(value) .. "\""
+        stringData = stringData .. "  " .. keyValue .. valueString .. ",\n"
+    end
+    stringData = stringData:sub(1, #stringData - 2) .. "\n}\n"
+    stringData = "Config_Table = "..stringData;
+    --print(stringData)
+    return stringData
+end
+
+if Files["Config.lua"] == nil then
+    if Config_Table == nil then
+        Config_Table = {}
+    end
+    SaveData("Version","V0.1");
+end

Src/GPIO.lua

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+Is_AutoClose = true;
+LightArr = {[1]=false,[2]=false,[3]=false,[4]=false}
+--Init GPIO params
+function InitGPIO()
+    gpio.mode(0,gpio.OUTPUT);
+    gpio.mode(1,gpio.OUTPUT);
+    gpio.mode(2,gpio.OUTPUT);
+    gpio.mode(3,gpio.OUTPUT);
+    gpio.mode(4,gpio.OUTPUT);
+    gpio.write(0,gpio.LOW);
+    gpio.write(1,gpio.LOW);
+    gpio.write(2,gpio.LOW);
+    gpio.write(3,gpio.LOW);
+    gpio.write(4,gpio.LOW);
+end
+--Push gpio to high
+function GPIOOn(gpioId)
+    if gpioId>=0 and gpioId<=4 then
+        gpio.write(gpioId,gpio.HIGH);
+        LightArr[gpioId] = true;
+        PageLight(LightArr);
+        if Is_AutoClose then
+            AutoClose(gpioId);
+        end
+    end
+    if gpioId == 99 then
+        gpio.write(0,gpio.HIGH);
+        gpio.write(1,gpio.HIGH);
+        gpio.write(2,gpio.HIGH);
+        gpio.write(3,gpio.HIGH);
+        gpio.write(4,gpio.HIGH);
+        LightArr = {[1]=true,[2]=true,[3]=true,[4]=true}
+        PageLight(LightArr);
+        if Is_AutoClose then
+            AutoCloseAll();
+        end
+    end
+    if gpioId == 10 then
+        Is_AutoClose = true;
+        PageLight(LightArr);
+    end
+end
+--Push gpio to low
+function GPIOOff(gpioId)
+    if gpioId>=0 and gpioId<=4 then
+        gpio.write(gpioId,gpio.LOW);
+        LightArr[gpioId] = false;
+        PageLight(LightArr);
+    end
+    if gpioId == 99 then
+        gpio.write(0,gpio.LOW);
+        gpio.write(1,gpio.LOW);
+        gpio.write(2,gpio.LOW);
+        gpio.write(3,gpio.LOW);
+        gpio.write(4,gpio.LOW);
+        LightArr = {[1]=false,[2]=false,[3]=false,[4]=false}
+        PageLight(LightArr);
+    end
+    if gpioId == 10 then
+        Is_AutoClose = false;
+        PageLight(LightArr);
+    end
+end
+
+function AutoClose(gpioId)
+    local mytimer = tmr.create()
+    mytimer:register(1000, tmr.ALARM_SINGLE, function() 
+        gpio.write(gpioId,gpio.LOW);
+        LightArr[gpioId] = false;
+        PageLight(LightArr);
+    end)
+    mytimer:start()
+end
+
+function AutoCloseAll()
+    local mytimer = tmr.create()
+    mytimer:register(1000, tmr.ALARM_SINGLE, function() 
+        gpio.write(0,gpio.LOW);
+        gpio.write(1,gpio.LOW);
+        gpio.write(2,gpio.LOW);
+        gpio.write(3,gpio.LOW);
+        gpio.write(4,gpio.LOW);
+        LightArr = {[1]=false,[2]=false,[3]=false,[4]=false}
+        PageLight(LightArr);
+    end)
+    mytimer:start()
+end
+InitGPIO();
+print("gpio1-5 init over,turn all gpio to output,low")

Src/OLED_SSD1306.lua

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+Id  = 0
+Sda = 5 -- GPIO14
+Scl = 6 -- GPIO12
+Sla = 0x3c
+i2c.setup(Id, Sda, Scl, i2c.SLOW)
+Disp = u8g2.ssd1306_i2c_128x64_noname(Id, Sla)
+print("Oled Init Success!");
+
+Screen_WIFINAME = "";
+Screen_IPADDRESS = "";
+Screen_VERSION = "";
+Screen_LightArr = {}
+--tips user use pc tools to link-AP
+function PageSerialNet()
+    Disp:clearBuffer()
+    Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:drawStr(0,10,"Serial-LinkMode");
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(0,26,"Open NetTools.exe ");
+    Disp:drawStr(0,36,"input ssid and pwd.");
+    Disp:updateDisplay();
+end
+--progress:1-100,tips loading and update from server
+function PageLoading(progress)
+    Disp:clearBuffer();
+    Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:drawStr(40,10,"DYTech");
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(16,32,"Check for update");
+    Disp:drawFrame(12,42,104,10);
+    Disp:drawBox(14,44,progress,6);
+    Disp:updateDisplay();
+end
+
+function DrawMainScene(wifiName,ipAddress,version)
+    --Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:drawStr(40,10,"DYTech");
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(0,26,"Wifi:"..wifiName);
+    Disp:drawStr(0,36,"Light Ctrl-UDP"..version);
+    Disp:drawStr(0,46,"S:"..ipAddress..":5000");
+end
+
+function DrawLight(lightArr)
+    Disp:drawCircle(16,56,4,u8g2.U8G2_DRAW_ALL);
+    Disp:drawCircle(32,56,4,u8g2.U8G2_DRAW_ALL);
+    Disp:drawCircle(48,56,4,u8g2.U8G2_DRAW_ALL);
+    Disp:drawCircle(64,56,4,u8g2.U8G2_DRAW_ALL);
+    Screen_LightArr = lightArr;
+    for index, value in ipairs(lightArr) do
+        if value then
+            Disp:drawDisc(16*index,56,4,u8g2.U8G2_DRAW_ALL);
+        end
+    end
+    if Is_AutoClose ~= nil then
+        if Is_AutoClose then
+            Disp:setFont(u8g2.font_6x10_tf);
+            Disp:drawStr(84,64,"Auto");
+        else
+            Disp:setFont(u8g2.font_6x10_tf);
+            Disp:drawStr(84,64,"Manual");
+        end
+    end
+end
+
+function PageMainScene(wifiName,ipAddress,version)
+    Screen_WIFINAME = wifiName;
+    Screen_IPADDRESS = ipAddress;
+    Screen_VERSION = version;
+    Disp:clearBuffer();
+    DrawMainScene(Screen_WIFINAME,Screen_IPADDRESS,Screen_VERSION)
+    Disp:updateDisplay();
+    --Disp:sendBuffer();
+end
+
+function PageLight(lightArr)
+    Disp:clearBuffer();
+    DrawMainScene(Screen_WIFINAME,Screen_IPADDRESS,Screen_VERSION);
+    DrawLight(lightArr);
+    Disp:sendBuffer();
+end
+
+function RefeshIP(ipAddress)
+    Screen_IPADDRESS = ipAddress;
+    Disp:clearBuffer();
+    DrawMainScene(Screen_WIFINAME,Screen_IPADDRESS,Screen_VERSION);
+    DrawLight(Screen_LightArr);
+    Disp:sendBuffer();
+end
+
+function PageConnecting()
+    Disp:clearBuffer()
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(0,10,"Connecting to internet");
+    Disp:drawStr(0,36,"Waiting...");
+    Disp:updateDisplay();
+end
+
+function PageConnectFaild(reason)
+    Disp:clearBuffer()
+    Disp:setFont(u8g2.font_unifont_t_symbols);
+    Disp:drawStr(0,10,"Connect Failed");
+    Disp:setFont(u8g2.font_6x10_tf);
+    Disp:drawStr(0,26,reason);
+    Disp:updateDisplay();
+end

Src/UDPService.lua

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+require("GPIO");
+function StartUDPService()
+    if UDPSocket == nil then
+        UDPSocket = net.createUDPSocket();
+        UDPSocket:listen(5000);
+        UDPSocket:on("receive", UDPService);
+        UDPPort, UDPIP = UDPSocket:getaddr();
+    else
+        UDPSocket:listen(5000);
+        UDPSocket:on("receive", UDPService);
+        UDPPort, UDPIP = UDPSocket:getaddr();
+    end
+    --print(string.format("local UDP socket address / port: %s:%d", UDPIP, UDPPort))
+end
+
+function UDPService(s, data, port, ip)
+    local commandSet = {};
+    for word in string.gmatch(data, "[^-]+") do 
+        table.insert(commandSet,word);
+    end
+    print("get data count" .. #commandSet);
+    if string.match(data,"^Light") then
+        if #commandSet==3 then
+            print(tonumber(commandSet[2]).."-"..commandSet[3])
+            if commandSet[3]=="On" and tonumber(commandSet[2])~=nil then
+                GPIOOn(tonumber(commandSet[2]));
+                s:send(port, ip, "Light "..commandSet[2].." "..commandSet[3]);
+            elseif commandSet[3]=="Off" and tonumber(commandSet[2])~=nil then
+                GPIOOff(tonumber(commandSet[2]));
+                s:send(port, ip, "Light "..commandSet[2].." "..commandSet[3]);
+            else
+                s:send(port, ip, "CommandFaild");
+            end
+        end
+    end
+end
+
+function StopUDPService()
+    if UDPSocket ~= nil then
+        UDPSocket:close();
+    end
+end
+--StartUDPService();

Src/WifiMgr.lua

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+StationCfg = {}
+IpCfg = {}
+
+--Load Config.lua and get value from Config_Table
+function AutoLink()
+    if GetData("SSID") ~= nil or GetData("Password") ~= nil then
+        --WifiSaved = dofile("eus_params.lua");
+        ManualLink(GetData("SSID"),GetData("Password"));
+    else
+        PageSerialNet();
+        return nil;
+    end
+end
+
+function ManualLink(ssid,passwd)
+    wifi.setmode(wifi.STATION)
+    StationCfg.ssid=ssid
+    StationCfg.pwd=passwd
+    StationCfg.save=false
+    wifi.sta.config(StationCfg)
+    wifi.sta.connect()
+    if wifi.sta.getip() == nil then
+        SetIPFromFile();
+    end
+    PageConnecting();
+    --OnLinkSucess();
+    print(wifi.sta.status());
+    --regist
+    wifi.eventmon.register(wifi.eventmon.STA_CONNECTED, function(T)
+        OnLinkSucess();
+    end)
+    wifi.eventmon.register(wifi.eventmon.STA_DISCONNECTED, function(T)
+        OnLinkFailed(T.reason);
+    end)
+end
+
+function SetIP(ipAddress,netmask,gateway)
+    IpCfg = {
+         ip = ipAddress,
+         netmask = netmask,
+         gateway = gateway
+        }
+    wifi.sta.setip(IpCfg)
+end
+
+--SetIP("192.168.1.115","255.255.255.0","192.168.1.1")
+function SaveIP(ipAddress,netmask,gateway)
+    SaveData("IpAddress",ipAddress);
+    SaveData("Netmask",netmask);
+    SaveData("Gateway",gateway);
+    SetIP(ipAddress,netmask,gateway);
+    RefeshIP(ipAddress);
+end
+
+function SaveSoftVersion(version)
+    SaveData("Version",version);
+end
+
+function SaveWifiInfo(ssid,passwd)
+    if GetData("SSID") == nil or GetData("Password") == nil then
+        SaveData("SSID",ssid);
+        SaveData("Password",passwd);
+        AutoLink();
+    else
+        SaveData("SSID",ssid);
+        SaveData("Password",passwd);
+    end
+    
+end
+
+function SetIPFromFile()
+    if Config_Table["IpAddress"]~=nil and Config_Table["Netmask"]~=nil and Config_Table["Gateway"]~=nil then
+        IpCfg = {
+            ip = Config_Table["IpAddress"],
+            netmask = Config_Table["Netmask"],
+            gateway = Config_Table["Gateway"]
+        }
+        wifi.sta.setip(IpCfg);
+    else
+        SetIP("192.168.1.210","255.255.255.0","192.168.1.1")
+        print("No Ip get,default to 192.168.1.210!");
+    end
+end
+
+
+function OnLinkSucess()
+    PageMainScene(StationCfg.ssid,wifi.sta.getip(),Config_Table["Version"]);
+    local lightArr = {[1]=false,[2]=false,[3]=false,[4]=false}
+    PageLight(lightArr)
+    --Service Open
+    StartUDPService();
+end
+
+function OnLinkFailed(reason)
+    PageConnectFaild(reason);
+end

Src/init.lua

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+--Start with this file
+--这个文件初始化会执行
+require("EasySave")
+require("GPIO")
+require("OLED_SSD1306")
+require("WifiMgr")
+require("UDPService")
+function Init()
+    --SetIP("192.168.1.115","255.255.255.0","192.168.1.1");
+    AutoLink();
+    --StartUDPService();
+end
+Init();

Third_Part_License/Json.lua.txt

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+--
+-- json.lua
+--
+-- Copyright (c) 2020 rxi
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy of
+-- this software and associated documentation files (the "Software"), to deal in
+-- the Software without restriction, including without limitation the rights to
+-- use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+-- of the Software, and to permit persons to whom the Software is furnished to do
+-- so, subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in all
+-- copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+-- SOFTWARE.
+--

Third_Part_License/json.lua

@@ -0,0 +1,364 @@
+local json = { _version = "0.1.2" }
+
+-------------------------------------------------------------------------------
+-- Encode
+-------------------------------------------------------------------------------
+
+local encode
+
+local escape_char_map = {
+  [ "\\" ] = "\\",
+  [ "\"" ] = "\"",
+  [ "\b" ] = "b",
+  [ "\f" ] = "f",
+  [ "\n" ] = "n",
+  [ "\r" ] = "r",
+  [ "\t" ] = "t",
+}
+
+local escape_char_map_inv = { [ "/" ] = "/" }
+for k, v in pairs(escape_char_map) do
+  escape_char_map_inv[v] = k
+end
+
+
+local function escape_char(c)
+  return "\\" .. (escape_char_map[c] or string.format("u%04x", c:byte()))
+end
+
+
+local function encode_nil(val)
+  return "null"
+end
+
+
+local function encode_table(val, stack)
+  local res = {}
+  stack = stack or {}
+
+  -- Circular reference?
+  if stack[val] then error("circular reference") end
+
+  stack[val] = true
+
+  if rawget(val, 1) ~= nil or next(val) == nil then
+    -- Treat as array -- check keys are valid and it is not sparse
+    local n = 0
+    for k in pairs(val) do
+      if type(k) ~= "number" then
+        error("invalid table: mixed or invalid key types")
+      end
+      n = n + 1
+    end
+    if n ~= #val then
+      error("invalid table: sparse array")
+    end
+    -- Encode
+    for i, v in ipairs(val) do
+      table.insert(res, encode(v, stack))
+    end
+    stack[val] = nil
+    return "[" .. table.concat(res, ",") .. "]"
+
+  else
+    -- Treat as an object
+    for k, v in pairs(val) do
+      if type(k) ~= "string" then
+        error("invalid table: mixed or invalid key types")
+      end
+      table.insert(res, encode(k, stack) .. ":" .. encode(v, stack))
+    end
+    stack[val] = nil
+    return "{" .. table.concat(res, ",") .. "}"
+  end
+end
+
+
+local function encode_string(val)
+  return '"' .. val:gsub('[%z\1-\31\\"]', escape_char) .. '"'
+end
+
+
+local function encode_number(val)
+  -- Check for NaN, -inf and inf
+  if val ~= val or val <= -math.huge or val >= math.huge then
+    error("unexpected number value '" .. tostring(val) .. "'")
+  end
+  return string.format("%.14g", val)
+end
+
+
+local type_func_map = {
+  [ "nil"     ] = encode_nil,
+  [ "table"   ] = encode_table,
+  [ "string"  ] = encode_string,
+  [ "number"  ] = encode_number,
+  [ "boolean" ] = tostring,
+}
+
+
+encode = function(val, stack)
+  local t = type(val)
+  local f = type_func_map[t]
+  if f then
+    return f(val, stack)
+  end
+  error("unexpected type '" .. t .. "'")
+end
+
+
+function json.encode(val)
+  return ( encode(val) )
+end
+
+
+-------------------------------------------------------------------------------
+-- Decode
+-------------------------------------------------------------------------------
+
+local parse
+
+local function create_set(...)
+  local res = {}
+  for i = 1, select("#", ...) do
+    res[ select(i, ...) ] = true
+  end
+  return res
+end
+
+local space_chars   = create_set(" ", "\t", "\r", "\n")
+local delim_chars   = create_set(" ", "\t", "\r", "\n", "]", "}", ",")
+local escape_chars  = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u")
+local literals      = create_set("true", "false", "null")
+
+local literal_map = {
+  [ "true"  ] = true,
+  [ "false" ] = false,
+  [ "null"  ] = nil,
+}
+
+
+local function next_char(str, idx, set, negate)
+  for i = idx, #str do
+    if set[str:sub(i, i)] ~= negate then
+      return i
+    end
+  end
+  return #str + 1
+end
+
+
+local function decode_error(str, idx, msg)
+  local line_count = 1
+  local col_count = 1
+  for i = 1, idx - 1 do
+    col_count = col_count + 1
+    if str:sub(i, i) == "\n" then
+      line_count = line_count + 1
+      col_count = 1
+    end
+  end
+  error( string.format("%s at line %d col %d", msg, line_count, col_count) )
+end
+
+
+local function codepoint_to_utf8(n)
+  -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa
+  local f = math.floor
+  if n <= 0x7f then
+    return string.char(n)
+  elseif n <= 0x7ff then
+    return string.char(f(n / 64) + 192, n % 64 + 128)
+  elseif n <= 0xffff then
+    return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128)
+  elseif n <= 0x10ffff then
+    return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128,
+                       f(n % 4096 / 64) + 128, n % 64 + 128)
+  end
+  error( string.format("invalid unicode codepoint '%x'", n) )
+end
+
+
+local function parse_unicode_escape(s)
+  local n1 = tonumber( s:sub(1, 4),  16 )
+  local n2 = tonumber( s:sub(7, 10), 16 )
+   -- Surrogate pair?
+  if n2 then
+    return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000)
+  else
+    return codepoint_to_utf8(n1)
+  end
+end
+
+
+local function parse_string(str, i)
+  local res = ""
+  local j = i + 1
+  local k = j
+
+  while j <= #str do
+    local x = str:byte(j)
+
+    if x < 32 then
+      decode_error(str, j, "control character in string")
+
+    elseif x == 92 then -- `\`: Escape
+      res = res .. str:sub(k, j - 1)
+      j = j + 1
+      local c = str:sub(j, j)
+      if c == "u" then
+        local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1)
+                 or str:match("^%x%x%x%x", j + 1)
+                 or decode_error(str, j - 1, "invalid unicode escape in string")
+        res = res .. parse_unicode_escape(hex)
+        j = j + #hex
+      else
+        if not escape_chars[c] then
+          decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string")
+        end
+        res = res .. escape_char_map_inv[c]
+      end
+      k = j + 1
+
+    elseif x == 34 then -- `"`: End of string
+      res = res .. str:sub(k, j - 1)
+      return res, j + 1
+    end
+
+    j = j + 1
+  end
+
+  decode_error(str, i, "expected closing quote for string")
+end
+
+
+local function parse_number(str, i)
+  local x = next_char(str, i, delim_chars)
+  local s = str:sub(i, x - 1)
+  local n = tonumber(s)
+  if not n then
+    decode_error(str, i, "invalid number '" .. s .. "'")
+  end
+  return n, x
+end
+
+
+local function parse_literal(str, i)
+  local x = next_char(str, i, delim_chars)
+  local word = str:sub(i, x - 1)
+  if not literals[word] then
+    decode_error(str, i, "invalid literal '" .. word .. "'")
+  end
+  return literal_map[word], x
+end
+
+
+local function parse_array(str, i)
+  local res = {}
+  local n = 1
+  i = i + 1
+  while 1 do
+    local x
+    i = next_char(str, i, space_chars, true)
+    -- Empty / end of array?
+    if str:sub(i, i) == "]" then
+      i = i + 1
+      break
+    end
+    -- Read token
+    x, i = parse(str, i)
+    res[n] = x
+    n = n + 1
+    -- Next token
+    i = next_char(str, i, space_chars, true)
+    local chr = str:sub(i, i)
+    i = i + 1
+    if chr == "]" then break end
+    if chr ~= "," then decode_error(str, i, "expected ']' or ','") end
+  end
+  return res, i
+end
+
+
+local function parse_object(str, i)
+  local res = {}
+  i = i + 1
+  while 1 do
+    local key, val
+    i = next_char(str, i, space_chars, true)
+    -- Empty / end of object?
+    if str:sub(i, i) == "}" then
+      i = i + 1
+      break
+    end
+    -- Read key
+    if str:sub(i, i) ~= '"' then
+      decode_error(str, i, "expected string for key")
+    end
+    key, i = parse(str, i)
+    -- Read ':' delimiter
+    i = next_char(str, i, space_chars, true)
+    if str:sub(i, i) ~= ":" then
+      decode_error(str, i, "expected ':' after key")
+    end
+    i = next_char(str, i + 1, space_chars, true)
+    -- Read value
+    val, i = parse(str, i)
+    -- Set
+    res[key] = val
+    -- Next token
+    i = next_char(str, i, space_chars, true)
+    local chr = str:sub(i, i)
+    i = i + 1
+    if chr == "}" then break end
+    if chr ~= "," then decode_error(str, i, "expected '}' or ','") end
+  end
+  return res, i
+end
+
+
+local char_func_map = {
+  [ '"' ] = parse_string,
+  [ "0" ] = parse_number,
+  [ "1" ] = parse_number,
+  [ "2" ] = parse_number,
+  [ "3" ] = parse_number,
+  [ "4" ] = parse_number,
+  [ "5" ] = parse_number,
+  [ "6" ] = parse_number,
+  [ "7" ] = parse_number,
+  [ "8" ] = parse_number,
+  [ "9" ] = parse_number,
+  [ "-" ] = parse_number,
+  [ "t" ] = parse_literal,
+  [ "f" ] = parse_literal,
+  [ "n" ] = parse_literal,
+  [ "[" ] = parse_array,
+  [ "{" ] = parse_object,
+}
+
+
+parse = function(str, idx)
+  local chr = str:sub(idx, idx)
+  local f = char_func_map[chr]
+  if f then
+    return f(str, idx)
+  end
+  decode_error(str, idx, "unexpected character '" .. chr .. "'")
+end
+
+
+function json.decode(str)
+  if type(str) ~= "string" then
+    error("expected argument of type string, got " .. type(str))
+  end
+  local res, idx = parse(str, next_char(str, 1, space_chars, true))
+  idx = next_char(str, idx, space_chars, true)
+  if idx <= #str then
+    decode_error(str, idx, "trailing garbage")
+  end
+  return res
+end
+
+
+return json