Optimize the lua module by add the __index and the __tostring meta-method

binding/lua/Ip2region.lua

@@ -11,10 +11,10 @@ local INDEX_BLOCK_LENGTH  = 12;
 local TOTAL_HEADER_LENGTH = 8192;
 local _M = {
     dbFile = "",
-    dbFileHandler = nil,
+    dbFileHandler = "",
     dbBinStr = "",
-    HeaderSip = nil, 
-    HeaderPtr = nil,
+    HeaderSip = "", 
+    HeaderPtr = "",
     headerLen = 0,
     firstIndexPtr = 0,
     lastIndexPtr = 0, 
@@ -22,12 +22,35 @@ local _M = {
 };
 
 _G["Ip2region"] = _M;
--- function _M:new(obj)
---     obj = obj or {};
---     setmetatable(obj, {__index = self});
---     return obj;
--- end
 
+-- set the __index to itself
+_M.__index = _M;
+
+-- set the print meta-method
+_M.__tostring = function(table)
+    local t = {
+        "dbFile=" .. table.dbFile,
+        "dbFileHandler=" .. table.dbFileHandler,
+        "headerLen=" .. table.headerLen,
+        "firstIndexPtr" .. table.firstIndexPtr,
+        "lastIndexPtr" .. table.lastIndexPtr,
+        "totalBlocks" .. table.totalBlocks
+    };
+
+    return table.concat(t, ",");
+end
+
+--[[
+construct method
+
+@param  obj
+@return Ip2region object
+--]]
+function _M:new(obj)
+    obj = obj or {};
+    setmetatable(obj, _M);
+    return obj;
+end
 
 
 --[[
@@ -203,11 +226,9 @@ function _M:binarySearch(ip)
 
     if ( self.totalBlocks == 0 ) then
         -- check and open the original db file
-        if ( self.dbFileHandler == nil ) then
-            self.dbFileHandler = io.open(self.dbFile, "r");
-            if ( not self.dbFileHandler ) then
-                return nil;
-            end
+        self.dbFileHandler = io.open(self.dbFile, "r");
+        if ( not self.dbFileHandler ) then
+            return nil;
         end
 
         self.dbFileHandler:seek("set", 0);
@@ -278,11 +299,9 @@ function _M:btreeSearch(ip)
     -- check and load the header
     if ( self.headerLen == 0 ) then
         -- check and open the original db file
-        if ( self.dbFileHandler == nil ) then
-            self.dbFileHandler = io.open(self.dbFile, 'r');
-            if ( not self.dbFileHandler ) then
-                return nil;
-            end
+        self.dbFileHandler = io.open(self.dbFile, 'r');
+        if ( not self.dbFileHandler ) then
+            return nil;
         end
 
         self.dbFileHandler:seek("set", 8);
@@ -400,4 +419,18 @@ function _M:btreeSearch(ip)
 end
 
 
+--[[
+close the object and do the basic gc
+]]--
+function _M.close(self)
+    if ( self.dbFileHandler ~= "" ) then
+        self.dbFileHandler:close();
+    end
+
+    if ( self.dbBinStr ~= "" ) then
+        self.dbBinStr = nil;
+    end
+end
+
+
 return _M;

binding/lua/README.md

@@ -27,15 +27,20 @@ ip2region>>
 * 2, 通过如下流程在你的lua程序中使用
 ```lua
 -- 包含模块
-local ip2region = require "Ip2region";
+require "Ip2region";
 
 -- 创建查询对象
 -- 设置ip2region.db的文件地址，dbFile表示ip2region.db数据库文件的地址
--- 或者通过设置属性，ip2region.dbFile = "ip2region.db file path";
-ip2region:setDbFile("ip2region.db file path");
+local ip2region = Ip2region:new({dbFile = "ip2region.db file path"});
+
+-- 也可以通过如下方式设置dbFile
+-- ip2region.dbFile = "ip2region.db file path";
+-- ip2region.setDbFile("ip2region.db file path");
+
+
 local data;
 
--- 查询，备注请使用“:”调用方法，不要使用“.”
+-- 查询，备注，尽量请使用“:”调用方法，使用“.”需要主动传递ip2region对象参数
 -- 1，binary查询
 data = ip2region:binarySearch("101.233.153.103");
 

binding/lua/testSearcher.lua

@@ -12,15 +12,20 @@ Usage: lua testSearcher.lua [ip2region db file] [algorithm]
     os.exit();
 end
 
-local ip2region = require "Ip2region";
+require "Ip2region";
 -- local cjson = require "cjson";
 -- local socket = require "socket";
 
 
 -- check and parse the dbFile and the method algorithm
--- set the dbFile
+-- Create a new ip2region object by the new interface
+local ip2region = Ip2region:new({dbFile = arg[1]});
+
+-- reset the dbFile by the follow two ways:
 -- ip2region.dbFile = arg[1];
-ip2region:setDbFile(arg[1]);
+-- ip2region:setDbFile(arg[1]);
+
+
 local algorithm = "btree";
 if ( arg[2] ~= nil ) then
     local arg_2 = string.lower(arg[2]);
@@ -74,3 +79,7 @@ while ( true ) do
         end
     end
 end
+
+-- close the object
+-- print(ip2region);
+ip2region:close();