从Win32消息值反推出名称串：自动代码生成

     这些天刚开始学习win32 API，出于对未知的不安，我试图用打印出所有爬过系统的消息的详细资料。其中有个简单的需求：从消息值反推出名称串，类似：

TRACE( TranslateMsgID(0x000F) ); // output: WM_PAINT

     在MSDN上搜了下，貌似没有API；也没怎么找到网上的资源，只好自己动手了。

 

 

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     我们现在就要获得一个完整的、C++程序能识别的消息值-消息名的表。Win32的大部分消息在 WinUser.h 中定义的，形如：

#define WM_PAINT 0x000F #define CB_ERRSPACE (-2) #define DM_SETDEFID (WM_USER+1)

     考虑到消息种类非常多，手工完成这个表很累也很容易出错。这里我想起一种有趣的技术：我们可以用C++写一个自动程序，扫描 WinUser.h 文件，自动完成所需的C++代码。碰巧逻辑也不难。以最重要的 WM_前缀消息为例，只要将所有以 "#define WM_” 开头的行提取出来，分别读出字符串 "WM_ PAINT" 以及剩下的串"0x000F"，就可以转化为类似下的 C/C++ 代码：

msg_name[ 0x000F ] = "WM_PAINT"; msg_name[ (-2) ] = "CB_ERRSPACE"; msg_name[ (WM_USER+1) ] = " DM_SETDEFID";

     这样算还相当稳健，规避了棘手的表达式解析。鉴于后面将提到的条件编译问题，保留表达式反倒比解出来更准确。
 

     这里共享一个简化的版本，包括 VS2008 的 WinUser.h 中所有 WM_ 前缀的消息(该文件可以编译通过): 

#include <windows.h> #include <iostream> #include <map> // Interface: const char* TranslateMsgID( int message_id ); // Implementation: static std::map<int, const char*> msg_name; static int InitMsgName(); int main() { using namespace std; cout << TranslateMsgID(0) << endl; cout << TranslateMsgID(WM_SHOWWINDOW) << endl; cout << TranslateMsgID(WM_USER) << endl; return 0; } const char* TranslateMsgID( int message_id ) { static int init = InitMsgName(); if( msg_name.find(message_id) == msg_name.end() ) return "Unknown MSG"; else return msg_name[ message_id ]; }; static int InitMsgName() { // This code is auto-generated from WinUser.h // and should use into other code //#define WM_NULL 0x0000 msg_name[ 0x0 ] = "WM_NULL"; //#define WM_CREATE 0x0001 msg_name[ 0x1 ] = "WM_CREATE"; //#define WM_DESTROY 0x0002 msg_name[ 0x2 ] = "WM_DESTROY"; //#define WM_MOVE 0x0003 msg_name[ 0x3 ] = "WM_MOVE"; //#define WM_SIZE 0x0005 msg_name[ 0x5 ] = "WM_SIZE"; //#define WM_ACTIVATE 0x0006 msg_name[ 0x6 ] = "WM_ACTIVATE"; //#define WM_SETFOCUS 0x0007 msg_name[ 0x7 ] = "WM_SETFOCUS"; //#define WM_KILLFOCUS 0x0008 msg_name[ 0x8 ] = "WM_KILLFOCUS"; //#define WM_ENABLE 0x000A msg_name[ 0xa ] = "WM_ENABLE"; //#define WM_SETREDRAW 0x000B msg_name[ 0xb ] = "WM_SETREDRAW"; //#define WM_SETTEXT 0x000C msg_name[ 0xc ] = "WM_SETTEXT"; //#define WM_GETTEXT 0x000D msg_name[ 0xd ] = "WM_GETTEXT"; //#define WM_GETTEXTLENGTH 0x000E msg_name[ 0xe ] = "WM_GETTEXTLENGTH"; //#define WM_PAINT 0x000F msg_name[ 0xf ] = "WM_PAINT"; //#define WM_CLOSE 0x0010 msg_name[ 0x10 ] = "WM_CLOSE"; //#define WM_QUERYENDSESSION 0x0011 msg_name[ 0x11 ] = "WM_QUERYENDSESSION"; //#define WM_QUERYOPEN 0x0013 msg_name[ 0x13 ] = "WM_QUERYOPEN"; //#define WM_ENDSESSION 0x0016 msg_name[ 0x16 ] = "WM_ENDSESSION"; //#define WM_QUIT 0x0012 msg_name[ 0x12 ] = "WM_QUIT"; //#define WM_ERASEBKGND 0x0014 msg_name[ 0x14 ] = "WM_ERASEBKGND"; //#define WM_SYSCOLORCHANGE 0x0015 msg_name[ 0x15 ] = "WM_SYSCOLORCHANGE"; //#define WM_SHOWWINDOW 0x0018 msg_name[ 0x18 ] = "WM_SHOWWINDOW"; //#define WM_WININICHANGE 0x001A msg_name[ 0x1a ] = "WM_WININICHANGE"; //#define WM_SETTINGCHANGE WM_WININICHANGE //#define WM_DEVMODECHANGE 0x001B msg_name[ 0x1b ] = "WM_DEVMODECHANGE/WM_DEVMODECHANGE"; //#define WM_ACTIVATEAPP 0x001C msg_name[ 0x1c ] = "WM_ACTIVATEAPP"; //#define WM_FONTCHANGE 0x001D msg_name[ 0x1d ] = "WM_FONTCHANGE"; //#define WM_TIMECHANGE 0x001E msg_name[ 0x1e ] = "WM_TIMECHANGE"; //#define WM_CANCELMODE 0x001F msg_name[ 0x1f ] = "WM_CANCELMODE"; //#define WM_SETCURSOR 0x0020 msg_name[ 0x20 ] = "WM_SETCURSOR"; //#define WM_MOUSEACTIVATE 0x0021 msg_name[ 0x21 ] = "WM_MOUSEACTIVATE"; //#define WM_CHILDACTIVATE 0x0022 msg_name[ 0x22 ] = "WM_CHILDACTIVATE"; //#define WM_QUEUESYNC 0x0023 msg_name[ 0x23 ] = "WM_QUEUESYNC"; //#define WM_GETMINMAXINFO 0x0024 msg_name[ 0x24 ] = "WM_GETMINMAXINFO"; //#define WM_PAINTICON 0x0026 msg_name[ 0x26 ] = "WM_PAINTICON"; //#define WM_ICONERASEBKGND 0x0027 msg_name[ 0x27 ] = "WM_ICONERASEBKGND"; //#define WM_NEXTDLGCTL