hi ther i wonder if you could help me on this simple task. I'm creating a GPS application to run on the XDA2, i'm using eVC++ to do the implementation.
at the moment i'm reading the GPS signal via bluetooth over a virtual COM port, the signal coming from the GPS if a ASCII sinal and i'm duimping this into a char buffer.
However i need to convert this to UNICODE in order to display it on the Pocket PC, how's best to convert a buffer full of ASCII into Unicode so i may display it?
I tried using MultiByteToWideChar(), but it doesn't seem to work properly, maybe i haven't set it up correctly? Could someone point me in the right direction!
Below is an example of what i tried:
Code:
char buf[50]; // contains output from GPS
TCHAR Message[50]; //where i intended to put the message so i could display it
MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, buf, -1, Message, 0);
Thank in advance
I'm sure it's not the right way to go about it, but I generally wsprintf for short strings.
However, don't listen to me, I'm a mad man. Check this page out instead:
http://www.i18nguy.com/unicode/c-unicode.html
V
Thanks for that, out of curiosity, how would you use wsprintf to convert ASCII to unicode, i tried that before with no real success!
The last value passed to MultiByteToWideChar tells this function the size of the result buffer, Message in your case. You have passed zero, all that does is makes the function return the size of a TCHAR variable it needs to put the Ascii input buf into.
You need to put sizeof(Message) as the last parameter and not zero.
The other way (better way ?) of doing this is first you call the MultiByteToWideChar function with the zero parameter as you have and then you malloc the result * sizeof(TCHAR).
Thanks for the advise, after looking into the function more i realised this is where i was going wrong, and i have now managed to make the conversion. Thanks for pointing that out though!
Hi Guys,
I'm going through the forum, I'm new to embedded developement, I've been able to do my first MessageBox("Hello World") in C using VS2005.
I want to understand how all this works, like :
- Accessing any "mass storage" device ? (the root FS ?, /, c:\, whatevername )
- Dumping the whole registry + values.
- Logging Process and activity even while "device locked" (new process, etc..)
And having more knownledge about the internals and devices, booting etc..
I'm kind of lost and my embedded knowledge is very thin..
The PPC i have is running WM5 on QTEK9100 (SPVM3000)..
Any pointers, posts, sources, small explication are more than welcome...
Hope you can help,
Regards,
r.
Welcome!
Wow those sure are some heavy requests for someone who is just starting.
How much experience do you have with C and Win32 APIs?
To start you off here is an excellent site for Windows Mobile programming tips and tricks:
www.pocketpcdn.com
Couple more pointers:
Device root is "\", no drives (SD cards mounted as folders) kind of like Linux.
All path are absolute - no ".\" or ".."
You can use standard C or Win32 functions for file operations.
Registry functions are also same as Desktop windows except you have to use the "Ex" version of of the function.
Example:
RegOpenKey - not implemented, use RegOpenKeyEx.
For process lists etc, google for ToolHelp32.
Thanks,
I'm at ease w/ ANSI C, have some familiarity w/ Win32 APIs,
but as far as I'm seeing I'm trying to code on Win32 Intel First,
then i try to "port" it to PocketPC Mobile, sometime it works
sometime functions doesn't even exists... MSDN doesn't seems very consistent over Win32 vs WM, but as I'm new I guess i'm missing a lot..
WinMain() prototype changes according to your target...otherwise
VS2005 yell about Overloading WinMain, It is VERY annnoying..anyway
Thanks for the links and the *Ex trick, I'll try to get deeper with this.
I have a strange problem trying to do my Own MessageBoxPrintf:
int MessageBoxPrintf(int, const char * title, const char * fmt, ...)
{
va_list ap;
char * buffer = NULL;
/* formatting and fixed size yes...*/
buffer = (char *) malloc (1024 * sizeof(char));
if (!buffer)
return -1;
memset(buffer, 0, 1024);
va_start(ap, fmt);
vsprintf(buffer, fmt, ap);
va_end(ap);
MessageBox(NULL, (LPCWSTR)buffer, (LPCWSTR)title, type);
return 0;
}
It does compile, but it display craps, since there is no stderr,stdout,stdin and
that I'm mostly coding on Win32/VMware, I don't know how to debug on my PPC (no USB connection), and I have no idea what's wrong.. it might be obvious, but it's late..
As I don't know what LPCWSTR stand for, I assumed char * and it did work on Win32 (XP) without hassle (except LPCWSTR types which are wrong for Win32 Target), so why it doesn't on WM5... is a mystery for me now..
Hope to be on speed ASAP to be able to release some stuff..
Thanks for your help,
Cheers,
r.
all WinAPI function on Pocket PC works with Unicode strings. So you have to convert from ANSI to Unicode.
ok, does the TEXT() macros convert to Unicode string, it seems not.
How to convert from ANSI to Unicode ?
you can work directly with wchar_t or use tchar that can be ansi or unicode, otherwise look for MultiByteToWideChar or CString object _T and TEXT Macro aren't for converting ansi but they makes unicode prefix strings... for example MessageBox(hWnd,_T("Hello World"),_T("my messagebox"),MB_OK);
I hope this help and don't forget MSDN have all replies
have fun,
Guybrush
ok it works! thanks!
just another question, how to dump the "disk" or how those devices are booting ROM?/Flash?
Currently I'm copying all the files from / to the SD card mount point is there anything else?
again thanks for your help.
++
r.
Hello everyone.
Recently, I've started developing some Android apps, and now I have a task and I don't know where to start So I guess I need some help
Ok, I need to write an app, which connects 2 phones via bluetooth (this part is done), and then, from one phone I should tell the other one to turn on its Camera and start recording video. Also I should be able to stop the recording.
And a bigger task should be able to send the recorded video to the remote phone, or stream it someway...
Is there any code/totorial/example on such a task? Only Starting recording also will be fine for now
Hope someone reads this, I need Your help!!!
In my Bluetooth apps (BlueMuze and Listables), I send little serializable meta objects. I think usually these are callted DTO for "data transfer object" in Java.
I call them something else but it doesnt matter what you call them as long as they are serializable and are exactly the same type of object with the same package name.
So I basically created my own little mini networking stack on top of the regular socket.
So the communication process might go something for this:
Let's say device1 is you control phone, device2 is the camera phone.
-> devices connected
device1 -> are you ready? -> device2
device2 -> yep, ready -> device1
device1 -> turn on camera -> device2
device2-> camera on preparing to return stream -> device 1
device2-> send byte array data for the stream -> device 1
Hopefully that should get the ball rolling and you can say if you need more detail or more basic info or whatever
I'm not really sure where you're starting from but figured I'd toss that out and you can tell me if that's too advanced or too basic or just right or whatever.
Thanks for the reply
Ok, I'm new at android development, so maybe it's gonna be a little tough
Any way. I've got that communication process "plan" in my mind already. Hust don't know how to realize it. As for a start, I'd like to know which are the classes/methods that control camera.
As I'm planning this app over Bluetooth (it's always free you know ), I have already done the connection part (little buggy, but will fix it). So I guess I can do these steps
device1 -> are you ready? -> device2
device2 -> yep, ready -> device1
Click to expand...
Click to collapse
Then goes the Camera thing.
And finally the byte stream... I guess if I manage to record something, I can find some methods for sending byte arrays??? I hope so!
So now my first task is the camera control I guess.
And what about your serializable meta objects and little mini networking stack? Please some more basic explanation on these...
Sure thing, in programming Serialization is basically just the "flattening" of an object to be passed over some data communication channel like Bluetooth/Serial or TCP/IP / Whatever. Basically it takes a full Java Object and compresses it down to it's raw byte equivalent.
To do this in Android/Java you make a class to hold some data and have it implement the Serializeable interface.
Here's an extra simple version of one of mine (you can add more complexity to yours as you need, this is just to demonstrate sending an object over the wire).
Code:
package com.alostpacket.listables.donate.vo;
import java.io.Serializable;
public class BluetoothMetaVO implements Serializable
{
//I made these codes up for myself
public static final int START_TRANSFER = 0;
public static final int TRANSFER_COMPLE = 1;
public static final int TRANSFER_ITEM = 2;
public static final int RESUME_TRANSFER = 3;
public static final int TYPE_PING = 9;
public static final int TYPE_REPLY = 10;
public static final int REPLY_OK = 11;
public static final int PING_OK = 12;
public static final int RECEIPT_OK = 13;
public static final int RECONNECT_PING = 14;
public static final int RECONNECT_REPLY = 15;
//this is the data you would end up sending
public int commandCode;
public int type;
public int numberItems;
public int id;
public BluetoothMetaVO()
{
}
}
To get the bytes you use and ObjectOutputStream and writeObject() probably to a ByteArrayOutputStream. (and later, for larger files a BufferedOutputStream).
If you're using the BluetoothChat example in the Android SDK as your starting point, you can pass the bytes to the write(byes[] b) method.
Then, on the receiving device, you use an ObjectInputStream and readObject to reconstitute the object.
You can then check the values of one of your properties (so for me I would check the commandCode) and act accordingly.
Wow this will really help. I'll start codeing first tjing in the morning
Sent from my HTC Hero using XDA App
Ok, now finally I tried some coding, but have lots of problems all the time. I steted with the BluetoothChatExample. But I think it's too mixed up for my case. So I decided to separate the Server app and the Client app. Let say, I need an app which creates a BT socket and listens to it. When a Client app connects to it, it allows the user to send a message to the client. Depending on the message, the Client should take a picture with it's camera and send it to the Server. When the Server receives a pic, it should store it on SD Card.
Anyone can help? Need some help on Client-Server connection...
I've been trying to get a simple file transfer between desktop app and phone app. The transfer works up to a point, when it simply ...stops dead.
The server(aka desktop client) enters the listening state, and the phone goes idle.
Anyone has any samples on transfers of large file (bigger than 1 MB)?
mcosmin222 said:
I've been trying to get a simple file transfer between desktop app and phone app. The transfer works up to a point, when it simply ...stops dead.
The server(aka desktop client) enters the listening state, and the phone goes idle.
Anyone has any samples on transfers of large file (bigger than 1 MB)?
Click to expand...
Click to collapse
Have you looked through GoodDayToDie's source code for the File Server? I wonder if he has anything in there that could make that work.
snickler said:
Have you looked through GoodDayToDie's source code for the File Server? I wonder if he has anything in there that could make that work.
Click to expand...
Click to collapse
lalz.
Completely forgot about that one xD
Meh he has it written in C++
Apparently, he didn't do anything that I didn't.
mcosmin222 said:
lalz.
Completely forgot about that one xD
Meh he has it written in C++
Click to expand...
Click to collapse
You can still utilize the transfer portion . I was thinking of seeing what I could do with sockets on the phone. I know it could come in handy somehow
snickler said:
You can still utilize the transfer portion . I was thinking of seeing what I could do with sockets on the phone. I know it could come in handy somehow
Click to expand...
Click to collapse
It's a pain in the ***.
It stops transfer at random points.
mcosmin222 said:
It's a pain in the ***.
It stops transfer at random points.
Click to expand...
Click to collapse
That doesn't surprise me at all for some reason.
Did you double-check your socket multithreading code?
I recently had problems with sockets and it turned out that I had the muti-threading thing wrong.
I think you shouldn't use only one connection and fail if it drops ...
ScRePt said:
Did you double-check your socket multithreading code?
I recently had problems with sockets and it turned out that I had the muti-threading thing wrong.
I think you shouldn't use only one connection and fail if it drops ...
Click to expand...
Click to collapse
What do you mean by socket multthreading code? You mean the use of async methods? or having the thread work on background, using the socket?
Take a look to the Tim Laverty's networking samples.
sensboston said:
Take a look to the Tim Laverty's networking samples.
Click to expand...
Click to collapse
That's what im doing (more or less)
@mcosmin222: The most common reason I saw for why that happened was the thread doing the transfer would crash. There's a lot of things that could cause such a crash, but because it's not the main thread or a UI thread, you don't see it. It just stops. In fact, even the debugger usually doesn't catch it (annoying as hell...)
There are a few common things that non-UI threads aren't allowed to do which you might be trying. For example, attempting to show a MessageBox on a non-UI thread will crash the thread (you can do it by adding a lambda or function to the dispatcher for the UI). In any case, feel free to use or adapt my code, or share yours here and if there's an obvious issue I'll point it out. Incidentally, you can set a larger buffer on the socket if you want the operation to complete without looping.
By the way, the only portion of my webserver that's written in C++ is the file I/O code, which I chose to do in C++ rather than .NET because the phone's stunted .NET framework makes it more difficult than I like to access arbitrary file paths. That code is all fairly clean wrappers around the Win32 calls; I suppose I could comment it more but it's very straightforward to read even if you aren't familiar with managed C++. The actual network code is entirely written in C# 4.5. You could actually simplify it a bit for a direct transfer app, too; I wrote it with a lot of multithreading in case I wanted to re-use the code somewhere that might be expected to have more than one client connecting at a time.
GoodDayToDie said:
@mcosmin222: The most common reason I saw for why that happened was the thread doing the transfer would crash. There's a lot of things that could cause such a crash, but because it's not the main thread or a UI thread, you don't see it. It just stops. In fact, even the debugger usually doesn't catch it (annoying as hell...)
There are a few common things that non-UI threads aren't allowed to do which you might be trying. For example, attempting to show a MessageBox on a non-UI thread will crash the thread (you can do it by adding a lambda or function to the dispatcher for the UI). In any case, feel free to use or adapt my code, or share yours here and if there's an obvious issue I'll point it out. Incidentally, you can set a larger buffer on the socket if you want the operation to complete without looping.
By the way, the only portion of my webserver that's written in C++ is the file I/O code, which I chose to do in C++ rather than .NET because the phone's stunted .NET framework makes it more difficult than I like to access arbitrary file paths. That code is all fairly clean wrappers around the Win32 calls; I suppose I could comment it more but it's very straightforward to read even if you aren't familiar with managed C++. The actual network code is entirely written in C# 4.5. You could actually simplify it a bit for a direct transfer app, too; I wrote it with a lot of multithreading in case I wanted to re-use the code somewhere that might be expected to have more than one client connecting at a time.
Click to expand...
Click to collapse
I am aware that some calls from background threads are not allowed, especially those that have to do with the UI thread.
This is the code for the server. It would seem this one is the problem, somewhere...I just can't see where...
I tried limiting the number of packages sent (that's what the timer is all about).
Code:
public class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousSocketListener
{
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public static string[] TransferStages = new string[] { "sendmetadataz-length", "sendmetadataz", "file-length", "file" };
public static int Index = -1;
public static List<string> FilePaths = new List<string>();
public static long CurrentStreamPosition = 0;
public static FileStream ifs;
static int pocketspersecond = 0;
static bool LimitExceded = false;
DispatcherTimer timer = new DispatcherTimer();
public static int CurrentArraySize = 0;
public static int FileIndex = 0;
public AsynchronousSocketListener()
{
timer.Interval = TimeSpan.FromSeconds(1);
timer.Tick += timer_Tick;
}
void timer_Tick(object sender, EventArgs e)
{
LimitExceded = false;
}
public static void StartListening()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[StateObject.BufferSize];
// Establish the local endpoint for the socket.
// Note: remember to keep the portnumber updated if you change
// it on here, or on the client
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Any, 13001);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(10);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nPress ENTER to continue...");
Console.Read();
}
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.UTF8.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
if (content.IndexOf("<EOF>") > -1)
{
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
// Respond to the client
Send(handler, content);
}
else
{
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
}
public static void Send(Socket handler, String data)
{
//handler.SendBufferSize = File.ReadAllBytes(@"D:\MUZICA\Activ - Visez.mp3").Length;
// handler.BeginSendFile(@"D:\MUZICA\Activ - Visez.mp3", new AsyncCallback(SendCallback), handler);
#region cotobatura
data = data.Replace("<EOF>", "");
if (data.Contains("sendmetadataz") && data.Contains("length")==false)
{
data = MainWindow.DataContextModel.Files.ElementAt(FileIndex).ToString()+"<EOF>";
byte[] byteData = Encoding.UTF8.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
else if (data.Contains("sendmetadataz-length"))
{
Index++;
if (Index >= MainWindow.DataContextModel.Files.Count)
{
//FileIndex++;
data = "TransfersComplete<EOF>";
}
data = Encoding.UTF8.GetByteCount((MainWindow.DataContextModel.Files.ElementAt(FileIndex).ToString() + "<EOF>").ToString()).ToString();
byte[] MetaDataLength = Encoding.UTF8.GetBytes(data);
handler.SendBufferSize = MetaDataLength.Length;
handler.BeginSend(MetaDataLength, 0, MetaDataLength.Length, 0, new AsyncCallback(SendCallback), handler);
}
else if (data.Contains("file-length"))
{
ifs = File.Open(MainWindow.DataContextModel.Files.ElementAt(FileIndex).Location, FileMode.Open);
byte[] gugu = Encoding.UTF8.GetBytes(ifs.Length.ToString());
handler.SendBufferSize = gugu.Length;
handler.BeginSend(gugu, 0, gugu.Length, 0, new AsyncCallback(SendCallback), handler);
}
else if (data.Contains("file") && data.Contains("length") == false)
{
//byte[] filedata = File.ReadAllBytes(MainWindow.DataContextModel.Files.ElementAt(FileIndex).Location);
//handler.BeginSend(filedata, 0, filedata.Length, 0,
//new AsyncCallback(SendCallback), handler);
byte[] filedata = new byte[150];
for (int i = 0; i < 150; i++)
{
if (CurrentStreamPosition < ifs.Length)
{
filedata[i] = (byte)ifs.ReadByte();
CurrentStreamPosition++;
CurrentArraySize++;
}
else
{
Array.Resize(ref filedata, CurrentArraySize);
break;
}
CurrentArraySize = 0;
}
// if (pocketspersecond == 25) LimitExceded = true;
//Thread.Sleep(1000);
handler.BeginSend(filedata, 0, filedata.Length, 0, new AsyncCallback(SendCallback), handler);
}
//handler.BeginSendFile(MainWindow.DataContextModel.Files.ElementAt(FileIndex).Location, filedata, null, TransmitFileOptions.ReuseSocket, new AsyncCallback(SendCallback), handler );
// What we want to send back in this application is a game move based on what
// has been received. So we call Play on the GameLogic to give us a move to send back
// data = GameLogic.Play(data);
// Convert the string data to byte data using ASCII encoding.
//byte[] byteData = Encoding.UTF8.GetBytes(data);
// Begin sending the data to the remote device.
//handler.BeginSend(byteData, 0, byteData.Length, 0,
// new AsyncCallback(SendCallback), handler);
#endregion
}
public static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
handler.Shutdown(SocketShutdown.Both);
handler.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
This is basically modified from the tick tak toe over sockets sample from MSDN.
The only possible call that would affect the UI is the call to the Console, but the code works fine for a while, after it just crashes.
I tried running the whole thing synchronously on the UI thread, the result appears to be the same.
In the Send method, the first 3 stages work (file-legth, metadata, metadata-length) and a few steps in the file stage (which actually sends the file).
AT some point, I assumed the thread was guilty somehow, but I just can't prove it. Running the thing directly on UI thread does not seem to change anything.
If the async method finishes and the socket gets disposed, the thread would "die".
PS: the entire thing is hosted by a WPF application.
Hmm... OK, there are several bugs here. I'm not sure which, if any, are responsible for the problem. I'd be tempted to overuse try-catch-log (for example, on the Send() function) and debug-print statements, but here are some things I can see that could cause a crash or other unexpected failure:
There is no guarantee that "ifs" is instantiated before use. If you for some reason skip the file-length step, the file step will crash with a null pointer exception.
The entire send function is hugely thread-unsafe. For example, if a second request arrives before you're done servicing the first one (which is entirely possible due to where the event gets signaled) then the values of "ifs" and "CurrentStreamPosition" and so on will be unpredictable at any given time. Since CurrentStreamPosition seems to be monotonically increasing, that's probably not going to cause an out-of-bounds exception, but it could cause you to enter a state where the test "if (CurrentStreamPosition < ifs.Length)" always fails.
The line "data = "TransfersComplete<EOF>";" never does anything; the next line (immediately following it) overwrites that variable. If you cared about that string, too bad.
FileIndex never changes; I hope you're only ever sending one file here...
You don't actually check that the number of bytes sent is the number you meant to send (admittedly, it *should* be, but there are cases where it won't be).
The last 150-byte chunk of every file transfer is truncated to the first byte. This is because "CurrentArraySize" is reset to 0 on every iteration of the byte-read loop (why use a byte-read loop?) so whenever "CurrentStreamPosition < ifs.Length" tests false, the "filedata" array will be resized to one byte (or zero if the file is an exact multiple of 150 bytes, which presumeably be correct).
There are probably more, but that's what jumped out at me (well, and some technically correct stylistic issues, like the "... == false" test). Given that your protocol seems to rely on end-of-message flags, I'm guessing that your problem is that since the last part of the file is almost always truncated, that marker is never getting sent. This probably leads to the client concluding that the server will be sending it more data, which it does by sending another "file" request. The server attempts to respond and immedately hits the CurrentStreamPosition < ifs.Length check, fails, goes to the else case, and tries to send a 1-byte packet containing a NULL byte.
Incidentally, does your file transfer protocol really require that the client request each 150-byte chunk one at a time, using a new TCP connection each time? That's... awfully inefficient.
GoodDayToDie said:
Hmm... OK, there are several bugs here. I'm not sure which, if any, are responsible for the problem. I'd be tempted to overuse try-catch-log (for example, on the Send() function) and debug-print statements, but here are some things I can see that could cause a crash or other unexpected failure:
There is no guarantee that "ifs" is instantiated before use. If you for some reason skip the file-length step, the file step will crash with a null pointer exception.
The entire send function is hugely thread-unsafe. For example, if a second request arrives before you're done servicing the first one (which is entirely possible due to where the event gets signaled) then the values of "ifs" and "CurrentStreamPosition" and so on will be unpredictable at any given time. Since CurrentStreamPosition seems to be monotonically increasing, that's probably not going to cause an out-of-bounds exception, but it could cause you to enter a state where the test "if (CurrentStreamPosition < ifs.Length)" always fails.
The line "data = "TransfersComplete<EOF>";" never does anything; the next line (immediately following it) overwrites that variable. If you cared about that string, too bad.
FileIndex never changes; I hope you're only ever sending one file here...
You don't actually check that the number of bytes sent is the number you meant to send (admittedly, it *should* be, but there are cases where it won't be).
The last 150-byte chunk of every file transfer is truncated to the first byte. This is because "CurrentArraySize" is reset to 0 on every iteration of the byte-read loop (why use a byte-read loop?) so whenever "CurrentStreamPosition < ifs.Length" tests false, the "filedata" array will be resized to one byte (or zero if the file is an exact multiple of 150 bytes, which presumeably be correct).
There are probably more, but that's what jumped out at me (well, and some technically correct stylistic issues, like the "... == false" test). Given that your protocol seems to rely on end-of-message flags, I'm guessing that your problem is that since the last part of the file is almost always truncated, that marker is never getting sent. This probably leads to the client concluding that the server will be sending it more data, which it does by sending another "file" request. The server attempts to respond and immedately hits the CurrentStreamPosition < ifs.Length check, fails, goes to the else case, and tries to send a 1-byte packet containing a NULL byte.
Incidentally, does your file transfer protocol really require that the client request each 150-byte chunk one at a time, using a new TCP connection each time? That's... awfully inefficient.
Click to expand...
Click to collapse
I know it is inefficient, but I'm rather new to sockets. I just want it to get working in a "beta stage" then ill optimize it (hance the FileIndex never increasing, the blatant lack of try-catch blocks).
On the client side, once the bytes in the buffer are processed, the server gets another send that to send the following 150 bytes (i use 150 just for the lulz).
So basically, the workfow is as follows:
ask metadata length >server gives the length >client adjusts buffer>ask metadata
ask metdata >server gives metdata>client processes the data>asks file length
ask file length>server gives file length>client adjusts a huge array of bytes in which the file will reside (i know this is horribly inefficient, but at some point i will write directly to a file stream)>asks for the first 150 bytes in the file.
server gets the request, sends 150 bytes to client>client copies the 150 bytes in the array created earlier, the asks for the next 150.
I am using 150 just to make sure the data never splits in more than one buffer.
When the file transfer occurs, a different message is used to signal the end of transfer. Client side counts the bytes it gets, and when it is equal to the file length, it no longer asks 150 bytes.
The whole thing seems to be safe from crashing until it gets to the part where it sends the file. I am aware that in the code i gave you there's some file streams not getting closed, but i've fixed that and the problem still occurs.
Since The debugger won't help me at all, I decided to use a WCF service instead.
mcosmin222 said:
What do you mean by socket multthreading code? You mean the use of async methods? or having the thread work on background, using the socket?
Click to expand...
Click to collapse
I mean worker threads not async.You will always have to have a thread in the background to "accept". once you accept you "read" in a new thread and the parent thread "accepts" again. Accept will freeze the thread.
On the other side, you simply "connect" and "write" in the same thread.
Read and Write is done in a loop via pre-defined buffers syncronously.
But if you want the server to give a response, the above flow is the other way around, and it is then when things get complicated. (server needs to "connect" and client needs to "accept" over a different set of ports and different threads)
Probably if you want to have reliable connection you will need the server to come back with a response "give me more" or sth.
So, trying to assist, it was my guess that drops or stalls could be because the above flow is not implemented properly.
Edit Oh ho, missed a whole new page so I am sorry if the reply is irrelevant now.
I would suggest you use the sync methods of sockets and not callbacks because is super easier to debug. ThreadPool.QueueSth (ctr + space I dont remember how it's called is your friend to handle threads yourself.
And try to separate pure socket handling from domain handling (lengths, metadata, etc). Send some bytes back and forth, clean-up and then move to domain specific things!
Moving the line that resets CurrentArraySize to outside of the for loop may well sove your problem. I'd try that first.
Optimization involves, among other things, removing try blocks. Unoptimized code, when you're trying to just make thigns work, ought to be full of them.
Don't forget that exceptions will not bubble up the call stack across threads. In addition to threads you create yourself, any async callback will happen on a different thread than the one that called the async function. If an uncaught exception occurs, the thread will die. If enough threads die, the program may crash (or at least hang) due to threadpool exhaustion.
GoodDayToDie said:
Moving the line that resets CurrentArraySize to outside of the for loop may well sove your problem. I'd try that first.
Optimization involves, among other things, removing try blocks. Unoptimized code, when you're trying to just make thigns work, ought to be full of them.
Don't forget that exceptions will not bubble up the call stack across threads. In addition to threads you create yourself, any async callback will happen on a different thread than the one that called the async function. If an uncaught exception occurs, the thread will die. If enough threads die, the program may crash (or at least hang) due to threadpool exhaustion.
Click to expand...
Click to collapse
I avoid try-catch in unoptimized code to see where actual exceptions occur (sometime the debugger doesn't break on exception).
Nop still not working.
The thread still appears to be crashing, even wrapped with try catch.
Do you at least know *which* function it's crashing in? Try putting a breakpoint on each function header and then, when one of them is hit, step through the execution until the thread dies. Work backward from there to find the problem.
GoodDayToDie said:
Do you at least know *which* function it's crashing in? Try putting a breakpoint on each function header and then, when one of them is hit, step through the execution until the thread dies. Work backward from there to find the problem.
Click to expand...
Click to collapse
The send function (the one with the case switch) appears to be crashing.
It executes the function then enters the listening stage (does not execute the callback).