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meet-dream — Mon, 28 May 2007 09:08:00 GMT

摘要: 初见boost的名字参敎ͼ��l��h一�U�“惊为天人”的感觉�Q�没惛_��.... 阅读全文

meet-dream 2007-05-28 17:08 发表评论

meet-dream — Mon, 28 May 2007 05:54:00 GMT

摘要: 阅读全文

meet-dream 2007-05-28 13:54 发表评论

boost asio 2:threading

meet-dream — Fri, 25 May 2007 06:06:00 GMT

摘要: 阅读全文

meet-dream 2007-05-25 14:06 发表评论

boost asio 1:how to use it

meet-dream — Fri, 25 May 2007 06:04:00 GMT

boost asio 是一个轻量��的异步网�l�库�Q�它有简�z�，��y�Q�高效，有良好的可扩展性，支持高�ƈ发的IO处理�Q�入门简单等诸多优点。boost asio在设计上采用和和ace�怼�的反应器�Q�proactor�Q�设计模式，同时内置了对多线�E�的支持�Q�针对不同的�q�_��Q�采用了最优的socket模型�Q�可以说能发挥机器的最大�ƈ发处理能力。同时在设计上，asio在接口上也有良好的可扩展性，几乎每种设计元素都可以根据要求订制和扩充�Q�可以进一步对模型�q�行抽象和徏模来建立自己需要的开发��^台。当�Ӟ��asio的最大缺点就是代码调试太难了�? 我们看一个asio的hello world�Q? #include #include #include void print(const boost::asio::error& /*e*/) { std::cout << "Hello, world!\n"; } int main() { // 定义一个io_service,它的作用是注册服务，调用一个异步请求完成后对应的操作（一个handle�Q? boost::asio::io_service io; //��d��一个定时器服务�Q? boost::asio::deadline_timer t(io, boost::posix_time::seconds(5)); //启动一个异步操作，该操作会记录于io_service 的一个队列中 t.async_wait(print); //每个注册的服务启动工�? io.run(); //5s后，定时器时间到�Q�print被调用，然后该handle�Q�print�Q�从队列中删�? return 0; } 可以看出�Q�对一个��用者来��_��asio的原理很��? 1。定义一个IO_Service 2.向IO_Service注册一个服�?该服务可以是io服务,也可以是定时器服�?当然,你也可以自己订制一个邮件服�? 3.在该服务上启动一个异步操�?�q�需要一个回调函�? 4.如果异步操作完成,你的回调函数会被调用 5.可能的错误处�? 理解asio的原理后�Q�写一个网�l�通信的程序简直是依葫芦画瓢的事了我们看一个时间查询的服务端： #include #include #include #include #include #include #include using boost::asio::ip::udp; std::string make_daytime_string() { using namespace std; // For time_t, time and ctime; time_t now = time(0); return ctime(&now); } class udp_server { public: //对象建立�Ӟ��注册了udp的socket服务�Q�接着��开始了一个异步的接收操作 udp_server(boost::asio::io_service& io_service) : socket_(io_service, udp::endpoint(udp::v4(), 13)) { start_receive(); } private: void start_receive() { //启动的异步操�? socket_.async_receive_from( boost::asio::buffer(recv_buffer_), //接收�~�冲�? remote_endpoint_, //存储��h��的客户地址�Q�ip+port boost::bind(&udp_server::handle_receive, this, //构造一个回调函敎ͼ�实际调用了成员函数handle_receive�Q�具体见boost::bind boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred) ); } void handle_receive(const boost::asio::error& error, std::size_t /*bytes_transferred*/) { //接到客户端的信息�Q�忽略了��h��内容�Q�直接发回本机的旉��Q�发送也是一个异步操�? if (!error || error == boost::asio::error::message_size) { boost::shared_ptr message( new std::string(make_daytime_string())); socket_.async_send_to(boost::asio::buffer(*message), remote_endpoint_, boost::bind(&udp_server::handle_send, this, message, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); start_receive(); } } //发送完成，忽略 void handle_send(boost::shared_ptr /*message*/, const boost::asio::error& /*error*/, std::size_t /*bytes_transferred*/) { } udp::socket socket_; udp::endpoint remote_endpoint_; boost::array recv_buffer_; }; int main() { try { boost::asio::io_service io_service; udp_server server(io_service); io_service.run(); } catch (std::exception& e) { std::cerr << e.what() << std::endl; } return 0; } 可以看到�Q�用asio开发一个网�l�服务端的程序一件多么简单的事。对此程序稍加改动，我们��可以徏立一个支持多�U�程�Q�高�q�发的网�l�服务程序�? 后面我们��l�分析asio的多�U�程支持�Q�多�~�冲�Q�网�l�流�{�更好的基础�Ҏ��?

meet-dream 2007-05-25 14:04 发表评论

a simple template hook class for function and member functions

meet-dream — Mon, 05 Mar 2007 15:51:00 GMT

Some times,we need too hook some function to do something that's not so easy to do with normally add somecode.A solution is to hook focused functions and interface.Here is a template hook class maybe help your work easier,which complie with vs2005.It midify the jmp table to replace the function,maybe not properly for other compliers.

class HookPfn
{
struct make_writeable
{
  void* p;
  MEMORY_BASIC_INFORMATION mbi_thunk;
  make_writeable(void* _p):p(_p)
  {
   VirtualQuery(p, &mbi_thunk, sizeof(MEMORY_BASIC_INFORMATION));
   VirtualProtect(mbi_thunk.BaseAddress, mbi_thunk.RegionSize, PAGE_READWRITE, &mbi_thunk.Protect);

  }
  ~make_writeable()
  {
   VirtualProtect(mbi_thunk.BaseAddress, mbi_thunk.RegionSize, mbi_thunk.Protect,&mbi_thunk.Protect);
  }
};
public:
template
void restore(F pfn,unsigned long handle)
{

  void* p;
  __asm mov eax,[pfn]
  __asm mov dword ptr[p],eax
  make_writeable write(p);
  __asm push ecx
  __asm mov eax,pfn
  __asm inc eax
  __asm mov ecx,handle
  __asm mov dword ptr[eax],ecx
  __asm pop ecx
}
template
unsigned long redirect(F1 pfn1,F2 pfn2)
{
   //should use restrict object prevent F1 and F2 's arguments and type not same
  void* p;
  __asm mov eax,[pfn1]
  __asm mov dword ptr[p],eax
  make_writeable write(p);

  unsigned long bas1,bas2,of1,of2,of;
  __asm push ecx
  __asm mov eax,pfn1
  __asm mov bas1,eax
  __asm inc eax
  __asm mov ecx,dword ptr[eax]
  __asm mov of1,ecx

  __asm mov eax,pfn2
  __asm mov bas2,eax
  __asm inc eax
  __asm mov ecx,dword ptr[eax]
  __asm mov of2,ecx

of=(bas2-bas1+of2-of1)+of1;

  __asm mov eax,pfn1
  __asm inc eax
  __asm mov ecx,of
  __asm mov dword ptr[eax],ecx
  __asm pop ecx
  return of1;
}

};

class mmt
{
public:
void donothing()
{
}
void donothing(int)
{
}
  void dosomething()
{
}
};

void fastcall(int a,int b)
{
}
void askcall(int,int)
{
}

It can be used as example:
int main()
{
HookMemberFunction sh;
unsigned long hd=sh.redirect(&fastcall,&askcall);//test api
fastcall(0,0);//two function
askcall(0,0);
sh.restore(&fastcall,hd);
askcall(0,0);
fastcall(0,0);
//test overlay functions(donothing)
typedef void (mmt::*sp)(void);
sp p1=&mmt::dosomething;
sp p2=&mmt::donothing;
hd=sh.redirect(p1,p2);
mmt mt;//a class
mt.donothing();
mt.dosomething();
sh.restore(p1,hd);
mt.donothing();
mt.dosomething();

}
Although it can be work right,addtionly we may be use it not properly.Youcan add some strict class to prevent bad use of it by check if the argument and return type is strictly same.,if you need it.

meet-dream 2007-03-05 23:51 发表评论