Jingle's Saying

I'm back, again.

2007-01-16T15:23:00.000+08:00

At last, it seems the undersea cable is repaired already, since I can again access my blog pages after more or less a month's time. I've ever said to keep updating this blog daily, but again, for some reasons, I failed on it. But, if time permits, I'll start again, just like the Matrix reload. During the two months passed by, a LOT of interesting things happened, but I can't record them all in time. I plan to recover them as much as I can from my memory, 'cause to memorize the interesting things is something more interesting. Have fun.

The right way to use boost::shared_ptr

2006-11-15T21:36:00.000+08:00

When do you really need boost::shared_ptr? Recently I find somehow I have misused it for some reason. I get to know smart know smart pointer from Scott Meyers' Effective STL, item 7, where he remind me to delete the pointers before the container is destroyed, but I neglect the precondition: "When using containers of *newed* pointers", yes, that's right, his point is focus on the newed pointers, that is to say, like your java habit of newing an object into a container, you'd like to do it like this: container.push_back(new foo), when you code like this, you should follow the instruction of item 7, because when something happened to the container unexpectly, that you get no chance to delete the pointers in it, it easily cause memory leak, because you have no handler to the pointer at all, while in java you don't have to worry about it, 'cause you can rely on garbage collection, while in C++, you have to take care of it all by yourself. So, Scott's advice is helpful, and under this condition, choosing smart pointer can save a lot of work. While in my project, the chance to put a newed point directly into a container is odd, so, introduce boost into the project is somehow not worthy. What I learn from this is when read something, I should pay attention to all the condition mentioned, then I can use the advice in a right place.

Debugging approach to an end

2006-11-10T22:39:00.000+08:00

Finally, the mess can call its end, something should be learnt, huh? I'm trying to find out something valuable in the past few days, what did I get? I paid my time on it, and of course, I should have some gain. Understanding smart pointer? Not quite that, I just use boost::shared_ptr to do some GC-like thing, but what is the mechanism behind it? I'm not sure I can tell it clearly. And for the smart pointer family in boost, shared_ptr is just one of them. Or the way to utilize third party code? Yes, that's helpful, while using API from others, I'm getting to know how to make my own code work like that way, even if just looks like that way, that's the right choice to write decent code. Or the ability of debugging? Yes, maybe, with the help of VC's powerful debugging tool. For a long time, I'm trying to get used to gcc and gdb, and actually did some toy coding, but you can't compare it with VC right? I have to admit that right now I'm just doing in a coder way, not a hacker way, although that's the way I'm dreaming of. Some other gain? Maybe the difference between Java and C++, but can I write down something here? Suddenly nothing in my mind at all. Perhaps it just doesn't come to the time.

Big map on MMS streaming over HTTP

2006-11-27T22:07:00.000+08:00

Many thanks to SDP team, their HTTP streaming protocol version 1.0 finally gives me the clear idea on how the handshake takes place between Windows Media Server and the client. The handshake contains two phases instead one, which I mistaken for a long time, and the wrong idea made my code work weird and I tried all means to find out the reason, and because of the lack of the big map on MMS streaming over HTTP, I did a lot of work in vain. That's the pay for exploring the unknown. Ok, let me introduce the big map to all you guys, though you can get the detail easily from SDP's document, I think the simple words below can give you some ease. Client: request ASF header in html form Server: reply with ASF header only, then disconnect from client Client: parse the ASF header, then re-connect to the server, and send the re-request Server: reply with ASF header again, followed by media packet That's it, that simple.

Codeplay

2006-11-21T11:42:00.000+08:00

The agreement on RTSP & the future...

2006-11-30T23:44:00.000+08:00

It seems in Windows media player 11 no more mms protocol is supported, though the request for a stream like mms://foo.com/bar.asf will still work, but it works as a protocol rollover URL, see more about rollover on MSDN. So, when it comes to request a stream for dedicate stream server, the best choice is RTSP, while is a open standard, other streaming protocol like Real and QuickTime from Apple also build their streaming service on it. It then seems appealing for us to concentrate on it to deliver better stream over P2P with the support of RTSP. I'm still wondering whether it's feasible to realize the interaction through P2P-based streaming service, maybe it'll help to give some clue, but the clear picture I still cannot see, more works need to be done before the real things get to work.

One month's work is rejected

2006-11-11T23:34:00.000+08:00

I can't exactly describe what my feeling when my one whole month's work is rejected, because of some function duplication. I think I must be very sad at that moment, or maybe some disappointing about myself. Whatever, every programmer should have this kind of feeling, I told myself then, sooner or later, it just comes. But what's more important is what do you learn from it, from the disapproval of your hard working? Sometimes hard working doesn't mean wise working, maybe you're just doing things in your own way, in your own world, but your product should be favored by users, when you ignore their feeling at all, even though you work hard on it, all you've done, excuse me of my directness, is just a piece of shit. Working blindly gives you nothing but frustration, a clever one works wisely by having more consideration, more communication, and more expression of his/her idea to everyone need to know it. Get to know all these, suddenly I feel peace inside, and when I told my girl friend about the rejecting thing, she responded to me, saying it just like my comforting to her while not telling her my bad encounter. :)

Loose couple

2006-11-09T23:05:00.000+08:00

There's already messy in my code, I begin to feel its reluctant to change. And because of my lack of experience on C++, I neglect the use of virtual base class as the interface, which can help me loose the couple between the right now tight relationship between classes. And when I notice that I should do something to get myself out of the mess, I find that it should be a hard time for me to change, but, what the hell, I deserve it, and that's all my fault. And also I have to admit that I've got not that much experience on developing big projects, I thought I should be prepared for it, after reading so much book on software engineering, but that's not the story, the experience comes only from the practice. And at this time, I get the really lesson for my own. I'm aware that I'm on the upgrade, but I want it to be quicker, I need the limited graduate time to be more efficient and when I one day graduate from the college, I get enough understanding which I should be proud of.

Finish my rejected work, it'll find its right place somewhere else

2006-11-12T13:38:00.000+08:00

The NetworkManager part of the project is reject yesterday, for the reason of re-implement the same function by two of us. It's really a shame, and you can imagine how is the communication among the team. That's all for the complaining, and what I'm thinking about right now, is how to deal with the almost finished thousands of lines code. I should finish it first, then make it easy to reuse -- I'll find its right place somewhere else, because I'm really confident on these codes. Its cohesion makes it easy to reuse, not interference other functions much, all the method calls are managed by the singleton NetworkManager, so the interface of the whole networking things are clear and simple. And I plan to make my code written before into a toolkit like thing, for the future use, that makes NetworkManager reasonable to take a place in it.

C'est La Vie

2006-10-29T19:22:00.000+08:00

Again and again, my life is just a circulation: rise up late in the morning, after a quick breakfast, sit in front of the computer in the lab, reading emails, news etc. before get to work, non-interrupted working till noon, quite accurate at 12:00 a.m. go for lunch, and hurry back when finished to take some break, 'cos when it passes 1:30 p.m. it's working time again. When it gets totally dark at 6:00 p.m. it's time for the day, but after supper, always, I'll go back to lab, finish something uncompleted in the daytime, extra working time without paying, but I don't care, I should learn more when I graduate from here. Boring, huh? Maybe, and these days I'm not quite in the mood, or gloomy you can say, all things trouble, and I'm trying to find a exit out of it. Hope soon.

I don't know where I'm going, but I'm on my way

2006-11-22T11:26:00.000+08:00

Somewhat lost these days, all day long's coding without progressing makes me tired and confused. I know I'm on the way to finish the project, but what about my ideas about P2P in the old days? Am I lost the passion on it? Or just some disappointing feeling surround me for a while? I have no idea which place these days work leads me to, I need some guidance, or just take a break and have some review of my thinking? Yep, I need a short term goal, and I need someone with me to work around it. Let me have a list here: A platform for: a. nowadays popular P2P file sharing protocol, in order to learn the actual behavior of them b. well known P2P lookup protocol, either unstructured or structured, to do some experiment on it, and get a benchmark c. better simulation on protocol d. from the data comparison, conclude a brand new/hybrid protocol for P2P network use e. empower the P2P network with efficient resource location mechanism, with the help of our lab's great ability on web searching & data mining An application built on the platform: a. show the ability of P2P and make it legal b. flexible with the underlying platform changes c. great user experience, trying to plant the decentralization into people's mind A demonstration of my ability on research: Paper is required Nothing is easy, but all the things are based on the experiment data, so, the runnable platform is on the first priority. Coding peacefully, but the communication during this period is critical for the whole plan.

Who's responsible for libjingle updating now?

2006-11-23T22:08:00.000+08:00

From Google's page, I'm redirected to the repository on sourceforge, where I find the updated version 0.3.0, which dated on March 16, 2006. That's all right for me at the time, but when I want to search some more detail on it, I googles it with CodeSearch, what a surprise, I get the result telling me, I can get a newer version 0.3.9 from a Gentoo's net-dist directory! What's more, I then googled more with the keywords: "libjingle gentoo", then, I see version 0.3.10, huh, now I just wonder where can I find the latest release of libjingle, just wonder, no other consideration related. How can a famous open source project act in such a mess? Just my complaining. By the way, I haven't read the code in gentoo's directory yet, maybe that's not the whole thing I'm complaining about, just version number changes. And PS again, from the discussion on Google Groups, I'm pointed to another project on Sourceforge Tapioca, where I get the version 0.3.10, hmm, that's more interesting now.Information update: the version 0.3.10 from Tapioca mentioned above is maintained by the Tapioca team, so the version number has little relation with the official one, and from the ChangeLog, you can see that, actually, there's no significant change made from the official version, just some modifications which is needed for their project.

Put pointer into STL::container

2006-11-14T23:29:00.000+08:00

I should declare my some misunderstanding on putting pointers into STL::container. One can directly put any kind of pointer of C++ style into any container that STL provides, except that, you should be responsible for the resource maintenance all along its life time, otherwise, there should be memory leak under some circumstance. While using boost::shared_ptr can save you out of this trouble, you have to pay something else on it, you need to know. With boost::shared_ptr, all the resource can be gracefully reclaimed, but the coding style can be slightly changed to accommodate to it, and sometimes it seems to be troublesome, just like to get the this pointer with it. Refer to this. Above all, my attitude is, when you are confident on the resource reclaiming, you don't need to employ boost's garbage collection like facility, but if you are not, boost is really good for you.

Note on using Visual C++ 2005 Express for Win32 developing

2006-11-16T20:17:00.000+08:00

Many thanks to the generous Microsoft, the Visual C++ 2005 Express Edition is enough for me to have a better experience on coding my project, and it's totally free. The trouble thing with the Platform SDK can be solved by this article: Using Visual C++ 2005 Express Edition with the Microsoft Platform SDK. And the Google's code libjingle also makes exciting. Surely, I can learn something from it. Looking forward.

Observer pattern and more...

2006-11-17T20:09:00.000+08:00

It takes me a lot of time to understand this design pattern, though I see it often, especially in java and UI code. But how to incorporate it into my own design, it seems difficult, that is to say, I do *NOT* really understand it ever. So, with GoF's classic book and Robert C. Martin's Agile attitude, again, I begin the learning process. While the re-reading goes on, from Google's code ( libjingle ), I find an excellent implementation of Observer pattern, the sigslot. It's very similar with Qt's Signals and Slots (which is powerful for GUI design ), while sigslot is very simple ( only one header file ) to get to the same purpose, yes, only from my view of coding the observer way. The only thing troubles is while it's easy coding, it's not that easy for you to read the code, you have to try your best to locate the connection method to make your understanding of the sigslot-way code. Here's also goes the introduction to it. And I decide to incorporate it into my project, that's great, many thanks to the author Sarah Thompson.

Decoupling legacy code

2006-11-18T19:54:00.000+08:00

Nearly one week's rumination on how to loose the coupling of the design, I have got a deeper understanding on how to write elegant code. Often I'd like to mention loose couple in design, but what on earth in practice, I *DO* the worst thing I can even expect. Still, I've got not enough experience on how to do the right coding thing. But the good thing is, here is the chance for me to enrich myself on the weakness mentioned above. How to define the relationship between each module, and how to organize the communication among them, I need a rendezvous in the project to route all the messages among all function modules, maybe some great ideas can be bought from SOA? Just like the ESB? I decide to call this module the core, and the former core I define now seems some basic supporting utilities and system call adapters. All the former core things can now be designed in a pure library way, and so do the upper concrete protocol implementation, they all communicate with each other through the right now core, and the final application built on my project just only see the protocol modules at all. And to make each module ( including the lower system adapter and the upper protocol modules ) pluggable, the core should be designed as flexible as possible, and the dynamic plugin mechanism should be deeply considered to achieve the goal. All the couplings are just with core and nothing else, that is what I need.

Stay hungry. Stay foolish

2006-11-07T21:49:00.000+08:00

Story from Steve Jobs, in which he, again, teaches me a lesson on how to follow my heart on each decision. What you really love, that's the only force to drive you forward. Steve has a magic life from my view, and the achievement he's got is so attractive to me. Not the fortune, but the way he is living, his attitude towards life. He's the master of his own life, but often, I just play the slave role in my dance floor. I have to obey countless rules from everywhere: you can't do this, you can't do that... And I am just jealousy about the free life style of others', when it really comes to me, always I choose to retreat, to hide, and to give up. Poor me, but I really want to make change. From where to start? What about from this blog?

Waiting

2006-11-02T14:02:00.000+08:00

Something like exciting, but still pretend to be calm facially, because I still don't want the weekend plan affect my daily work in the lab. The most beautiful season in Beijing is autumn, just like the photo says, the blue sky, pure blue, and the yellow leaves. But the time in Chengdu, still in the foggy state. That is the most significant difference between the two cities. Missing the yellow ginkgo leaves in my former college, but it seems two days journey is not long enough for me to go back there and have a look.

Flying

2006-11-03T23:02:00.000+08:00

One whole day's meeting, and I have to be prepared for the night's flying back to Chengdu. The seminar this morning makes me confused because I'm quite a idiot on the complex networks. While the P2P network has the significant characters of complex networks, the ignorant of the idea of it can just make my understanding on P2P one-sided. But I have the habit to have the big map on any thing, so the afternoon, I cost a notable amount of time on the basic concept on it, when I get a call, saying my flight canceled! I should take off at 18:50, and arrive at Chengdu at 21:20, and she said she would waiting for me at the airport. I should tell her first, that is my first thought in my mind while I'm listening to the phone, then I agree to change the flight to a later on taking off one, which results in my arriving after 23:00. But after all, I'm back, with the best wishes to her birthday.

Birthday preview

2006-11-04T22:42:00.000+08:00

It's not so easy as expected. We prepared a lot -- a lot of talking, to make us understood to each other clearly -- before the birthday comes. I need this kind of talk, just like my affection about the movie series : Before Sunrise and Before Sunset. The talk make us get closer to each other. I don't want any misunderstanding between us, and I'm not that good to guess what people are thinking right now, so I choose to talk it out, and of course, in the way we both feel comfort. Though some words may be tough, but I should be honest to you, and be faithful to myself. And thanks to the God, and actually we DO try to get close to God and the Buddha today, we finally get to each other. So the following things can be work out smoothly...

Happy Birthday :)

2006-11-05T22:31:00.000+08:00

Happy birthday, my girl. Hope you happy ever after.

Back to work

2006-11-06T22:29:00.000+08:00

Back to work, lot of things are waiting for me to do. But, the two days' long distance journey recharge me full of power. No need to any more summaries here 'cos we've been talking about the meaning of the going back and the happy birthday a lot in the past two days. But I want to mention just one sentence here: it means a lot and is important for the both of us. So, it's worthwhile, and what I need to do, to make it better, is focus on my own work, while she put all her heart on hers, to make the coming three months fruitful. We have ambitions, and we need time to achieve them with our concentration and hard working. The debugging thing left to be finished last week is finally dealt with today. Still some coordination among interfaces, the next step to finish the listeners, which make the callback method work properly. Try to finish it by this weekend, and the code integration may cost me a lot of energy I can foresee. So, be prepared for it.

Cold or Hot?

2006-11-08T22:14:00.000+08:00

Suddenly, the temperature drops down shapely. And it's getting to feel the cold of real winter. I have to put on more clothes, but when I arrive the lab, I have to do the reverse thing -- take off most of them because the high temp cause by the overdoing heating. I'm not complaining it here, just because when I get to the watershed between the hot inside and cold outside, it takes time to adapt to the change. I said more than one million times I just enjoy the peaceful life, which just like the feeling of still water, which can run long away. Passion? I need it, but it cannot be the regular style of my life, too many ups and downs can only make me frustrated and lose myself. That's my life style, steady while with some passion sometime. I enjoy it so.

Listen to your heart

2006-11-01T21:51:00.000+08:00

Come back from the piano recital, quiet, it's my only feeling for the past one hours and a half. Any tiny sound can be heared so clearly that, the rythm from the piano on the dance floor sounds more concrete and it seems it's visualable and touchable. Or just my self feeling on my own? I can hear my heart to tell me the story that the music tells, and my mood follows it all the way. What a shame, I can't describe my own thinking out into words here. One more song may help: listen to your heart, version by Roxette or by D.H.T, either will help. Debugging continues today, weird error output is generated just because only one header file not included. The main problem makes the debugging so complicate is the dim planning of the interface after import the smart pointer. It' s hard to decide the choice then, so, its debugging matters too. And I am now thinking about whether the STL using in the project is proper or not, you know, effeciency matters. But after all, progress made through the day, and tomorrow, I believe more result can be achieved. The forum on China-Africa cooperation is held from Nov. 3 - Nov. 5，traffic control is employed, maybe I should start off earlier in case of missing the plane.

E-ticket and debugging

2006-10-31T20:21:00.000+08:00

Ticket bought, though I cost my one month's income, hope it worth. Today my concentration is one the debugging of my legacy code, some interface mismatches make the whole work confusing, and the callback function implemented through listener should be finished while debugging, a whole-thing view required to be more clear to carding my thinking. Some details of the C++ language itself should be clear through this procedure, especially the ones on template and generic programming. Should resume the work after writing this blog, and today I cancel my weekly badminton playing to make the whole thing go smoothly, tomorrow night I can take a break as a compensation, huh, to attend a piano recital by Peter Bithell at PKU, so work happily for the force coming happiness.