Hello David, > How do I know the maximum size possible?
at receiving side, specially depending on the speed of your own program you mostly never get above 8 kb. However I have seen receiving packets 10 time as high. But you dont have to care mutch, if you receive not all, then OnDataAvailable is immediatly called again, meaning if you have a temporary buffer that is to small, however if you receive on the stack then you can make him (almost) as large you wants. > I certainly don't want to malloc 100KB for a TCP packet... See above, you dont need to. --- Rgds, Wilfried [TeamICS] http://www.overbyte.be/eng/overbyte/teamics.html http://www.mestdagh.biz Saturday, October 29, 2005, 20:25, Kei wrote: > Hi! > I think I'm going to accept the reality that... TCP packets are splitted > into arbitrary sizes.. but!!! > How do I know the maximum size possible? What is the maximum size that a > packet can be? I certainly don't want to malloc 100KB for a TCP packet... > Thanks! > David > Wilfried Mestdagh wrote: >>Hello David, >> >> >> >>>Hi! I'm new to ICS! >>> >>> >> >>Welcome to the group :) >> >> >> >>>A->>B: msg hello >>>B->>A: msg yo! how's it going? >>> >>> >> >>Yes that's the way to go. Design a user made proto for what you intend >>to do. >> >> >> >>>If A is larger than the default buffer size (256 chars) then the A >>>(sender) will warn B in advance >>> >>> >> >>You can do that, but is not nececary. Also you will maybe have a very >>mutch allocation / deallocation of memory and you can eventually end up >>with fragmented memory where you have not a nice large block in it at >>the moment you need it. But it can work, just think over carefully. A >>better idea is often to make a receive buffer that grows automatically >>if (and only if) needed, and then just reuse that buffer over and over >>again. Then you have some (re)allocation in begin but then stable. >> >> >> >>>TWSocket will automatically split it into packets, >>> >>> >> >>Winsock will split in packets as large as the MTU (around 1500 bytes). >>Eventually data can (and will if high speed) arrive as 1 large packet >>but not necacarely. >> >> >> >>>I really want the sender side to send the 1MB file all at once, since I >>>do the FileWrite() right after Receive().... >>> >>> >> >>No you cannot. Winsock does not respect packet boundaries, but (see >>prior paragraph) there are no megabytes TCP packets. >> >>You have to receive all data chuncks into a buffer, and when you >>received them all then you save to file (or save every packet direct to >>disk). There is no problem to know the moment of close the file because >>you know the length of the data from your protocol. >> >>--- >>Rgds, Wilfried [TeamICS] >>http://www.overbyte.be/eng/overbyte/teamics.html >>http://www.mestdagh.biz >> >>Saturday, October 29, 2005, 11:01, Kei wrote: >> >> >> >>>Hi! I'm new to ICS! >>> >>> >> >> >> >>>I am designing a simple protocol that will be mainly used locally (as a >>>database server backend)..so I'm guessing I could send up to 2GB of >>>stuff without hassle (BLOBs, for example). Right now I'm just >>>experimenting with the facility for two parties to effectively "talk" to >>>each other, even with long long messages, and with binary data transfer. >>>For example, for sending a message, the command is "msg [text]" >>> >>> >> >>A->>B: msg hello >>B->>A: msg yo! how's it going? >> >> >> >>>If A is larger than the default buffer size (256 chars) then the A >>>(sender) will warn B in advance, like this: "hey! I'm gonna send you >>>10000 bytes of text" >>> >>> >> >>A->>B: longmsg 10000 >>B->>A: ready msg >>A->>B: msg blahblahblah...........blah! >> >> >> >>>In this case, B will be notified of the text size, then when >>>OnClientDataAvailable() event comes, it will malloc a bigger buffer, >>>then Receive(CustomSized_Buffer, SizeHeToldMe). Similarly Im considering >>>the same mechanism to send binary data. But if the file is slightly >>> >>> >>larger (>>10KB) then TWSocket will automatically split it into packets, >> >> >>>which I don't want it to do: >>> >>> >> >>A->>B: upload 1048576 picture.jpg >>B->>A: ready upload >>A->>B: 01001010101010.. (10720 bytes) >>A->>B: 11111010101012.. (10720 bytes) >> >> >>>: >>>: >>> >>> >>A->>B: 01001010101010.. (4023 bytes) >> >> >> >>>I really want the sender side to send the 1MB file all at once, since I >>>do the FileWrite() right after Receive().... >>> >>> >> >> >> >>>Could anybody please help me on this issue? >>> >>> >> >> >> >>>Thanks! >>> >>> >> >> >> >>>David >>> >>> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> -- To unsubscribe or change your settings for TWSocket mailing list please goto http://www.elists.org/mailman/listinfo/twsocket Visit our website at http://www.overbyte.be
