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• Moq and accessing called parameters

  - by lozzar

  I've just started to implement unit tests (using xUnit and Moq) on an already established project of mine. The project extensively uses dependency injection via the unity container. I have two services A and B. Service A is the one being tested in this case. Service A calls B and gives it a delegate to an internal function. This 'callback' is used to notify A when a message has been received that it must handle. Hence A calls (where b is an instance of service B): b.RegisterHandler(Guid id, Action<byte[]> messageHandler); In order to test service A, I need to be able to call messageHandler, as this is the only way it currently accepts messages. Can this be done using Moq? ie. Can I mock service B, such that when RegisterHandler is called, the value of messageHandler is passed out to my test? Or do I need to redesign this? Are there any design patterns I should be using in this case? Does anyone know of any good resources on this kind of design?

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• Getting started with character and text processing (encoding, regular expressions)

  - by TK

  I'd like to learn foundations of encodings, characters and text. Understanding these is important for dealing with a large set of text whether that are log files or text source for building algorithms for collective intelligence. My current knowledge is pretty basic: something like "As long as I use UTF-8, I'm okay." I don't say I need to learn about advanced topics right away. But I need to know: Bit and bytes level knowledge of encodings. Characters and alphabets not used in English. Multi-byte encodings. (I understand some Chinese and Japanese. And parsing them is important.) Regular expressions. Algorithm for text processing. Parsing natural languages. I also need an understanding of mathematics and corpus linguistics. The current and future web (semantic, intelligent, real-time web) needs processing, parsing and analyzing large text. I'm looking for some resources (maybe books?) that get me started with some of the bullets. (I find many helpful discussion on regular expressions here on Stack Overflow. So, you don't need to suggest resources on that topic.)

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• Load Assembly in New AppDomain without loading it in Parent AppDomain

  - by Al Katawazi

  I am attempting to load a dll into a console app and then unload it and delete the file completely. The problem I am having is that the act of loading the dll in its own AppDomain creates a reference in the Parent AppDomain thus not allowing me to destroy the dll file unless I totally shut down the program. Any thoughts on making this code work? string fileLocation = @"C:\Collector.dll"; AppDomain domain = AppDomain.CreateDomain(fileLocation); domain.Load(@"Services.Collector"); AppDomain.Unload(domain); BTW I have also tried this code with no luck either string fileLocation = @"C:\Collector.dll"; byte[] assemblyFileBuffer = File.ReadAllBytes(fileLocation); AppDomainSetup domainSetup = new AppDomainSetup(); domainSetup.ApplicationBase = Environment.CurrentDirectory; domainSetup.ShadowCopyFiles = "true"; domainSetup.CachePath = Environment.CurrentDirectory; AppDomain tempAppDomain = AppDomain.CreateDomain("Services.Collector", AppDomain.CurrentDomain.Evidence, domainSetup); //Load up the temp assembly and do stuff Assembly projectAssembly = tempAppDomain.Load(assemblyFileBuffer); //Then I'm trying to clean up AppDomain.Unload(tempAppDomain); tempAppDomain = null; File.Delete(fileLocation);

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• Speed up bitstring/bit operations in Python?

  - by Xavier Ho

  I wrote a prime number generator using Sieve of Eratosthenes and Python 3.1. The code runs correctly and gracefully at 0.32 seconds on ideone.com to generate prime numbers up to 1,000,000. # from bitstring import BitString def prime_numbers(limit=1000000): '''Prime number generator. Yields the series 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 ... using Sieve of Eratosthenes. ''' yield 2 sub_limit = int(limit**0.5) flags = [False, False] + [True] * (limit - 2) # flags = BitString(limit) # Step through all the odd numbers for i in range(3, limit, 2): if flags[i] is False: # if flags[i] is True: continue yield i # Exclude further multiples of the current prime number if i <= sub_limit: for j in range(i*3, limit, i<<1): flags[j] = False # flags[j] = True The problem is, I run out of memory when I try to generate numbers up to 1,000,000,000. flags = [False, False] + [True] * (limit - 2) MemoryError As you can imagine, allocating 1 billion boolean values (1 byte 4 or 8 bytes (see comment) each in Python) is really not feasible, so I looked into bitstring. I figured, using 1 bit for each flag would be much more memory-efficient. However, the program's performance dropped drastically - 24 seconds runtime, for prime number up to 1,000,000. This is probably due to the internal implementation of bitstring. You can comment/uncomment the three lines to see what I changed to use BitString, as the code snippet above. My question is, is there a way to speed up my program, with or without bitstring?

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• Code for decoding/encoding a modified base64 URL

  - by Kirk Liemohn

  I want to base64 encode data to put it in a URL and then decode it within my HttpHandler. I have found that Base64 Encoding allows for a '/' character which will mess up my UriTemplate matching. Then I found that there is a concept of a "modified Base64 for URL" from wikipedia: A modified Base64 for URL variant exists, where no padding '=' will be used, and the '+' and '/' characters of standard Base64 are respectively replaced by '-' and '_', so that using URL encoders/decoders is no longer necessary and has no impact on the length of the encoded value, leaving the same encoded form intact for use in relational databases, web forms, and object identifiers in general. Using .NET I want to modify my current code from doing basic base64 encoding and decoding to using the "modified base64 for URL" method. Has anyone done this? To decode, I know it starts out with something like: string base64EncodedText = base64UrlEncodedText.Replace('-', '+').Replace('_', '/'); // Append '=' char(s) if necessary - how best to do this? // My normal base64 decoding now uses encodedText But, I need to potentially add one or two '=' chars to the end which looks a little more complex. My encoding logic should be a little simpler: // Perform normal base64 encoding byte[] encodedBytes = Encoding.UTF8.GetBytes(unencodedText); string base64EncodedText = Convert.ToBase64String(encodedBytes); // Apply URL variant string base64UrlEncodedText = base64EncodedText.Replace("=", String.Empty).Replace('+', '-').Replace('/', '_'); I have seen the Guid to Base64 for URL StackOverflow entry, but that has a known length and therefore they can hardcode the number of equal signs needed at the end.

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• Is there any danger in calling free() or delete instead of delete[]? [closed]

  - by Matt Joiner

  Possible Duplicate: ( POD )freeing memory : is delete[] equal to delete ? Does delete deallocate the elements beyond the first in an array? char *s = new char[n]; delete s; Does it matter in the above case seeing as all the elements of s are allocated contiguously, and it shouldn't be possible to delete only a portion of the array? For more complex types, would delete call the destructor of objects beyond the first one? Object *p = new Object[n]; delete p; How can delete[] deduce the number of Objects beyond the first, wouldn't this mean it must know the size of the allocated memory region? What if the memory region was allocated with some overhang for performance reasons? For example one could assume that not all allocators would provide a granularity of a single byte. Then any particular allocation could exceed the required size for each element by a whole element or more. For primitive types, such as char, int, is there any difference between: int *p = new int[n]; delete p; delete[] p; free p; Except for the routes taken by the respective calls through the delete-free deallocation machinery?

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• HTTP requests and Apache modules: Creative attack vectors

  - by pinkgothic

  Slightly unorthodox question here: I'm currently trying to break an Apache with a handful of custom modules. What spawned the testing is that Apache internally forwards requests that it considers too large (e.g. 1 MB trash) to modules hooked in appropriately, forcing them to deal with the garbage data - and lack of handling in the custom modules caused Apache in its entirety to go up in flames. Ouch, ouch, ouch. That particular issue was fortunately fixed, but the question's arisen whether or not there may be other similar vulnerabilities. Right now I have a tool at my disposal that lets me send a raw HTTP request to the server (or rather, raw data through an established TCP connection that could be interpreted as an HTTP request if it followed the form of one, e.g. "GET ...") and I'm trying to come up with other ideas. (TCP-level attacks like Slowloris and Nkiller2 are not my focus at the moment.) Does anyone have a few nice ideas how to confuse the server and/or its modules to the point of self-immolation? Broken UTF-8? (Though I doubt Apache cares about encoding - I imagine it just juggles raw bytes.) Stuff that is only barely too long, followed by a 0-byte, followed by junk? et cetera I don't consider myself a very good tester (I'm doing this by necessity and lack of manpower; I unfortunately don't even have a more than basic grasp of Apache internals that would help me along), which is why I'm hoping for an insightful response or two or three. Maybe some of you have done some similar testing for your own projects? (If stackoverflow is not the right place for this question, I apologise. Not sure where else to put it.)

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• Excel 2007 file writer in C# results in a corrupt file

  - by Martin

  Hi, I am using a BinaryReader to read an Excel 2007 file from an Exchange mailbox using a OWA, the file is then written to disk using a BinaryWriter. My problem is that the two files don't match when the writer finishes. Worse still Excel 2007 won't open the writen file. Previously Excel 2003 has had no problem with the solution below. And Excel 2007 doesn't have an issue if the file is an Excel 2003 format file, only if the file format is Excel 2007 (*.xlsx). BinaryReader: using(System.IO.Stream stream = resource.GetInputStream(attachedFiles[k].Address)) { using(System.IO.BinaryReader br = new System.IO.BinaryReader(stream)) { attachment.Data = new byte[attachedFiles[k].Size]; int bufPosn=0, len=0; while ((len = br.Read( attachment.Data, bufPosn, attachment.Data.Length-bufPosn )) > 0) { bufPosn += len; } br.Close(); } } BinaryWriter: FileStream fs = new FileStream(fileName, FileMode.Create); BinaryWriter binWriter = new BinaryWriter(fs); binWriter.Write( content, 0, content.Length ); binWriter.Close(); fs.Close(); Suggestions gratfully received.

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• Creating files with french characters and encoding.

  - by Kevin

  HI, I am creating a file like so. FileStream temp = File.Create( this.FileName ); Then putting data in the file like so. this.Writer = new StreamWriter( this.Stream ); this.Writer.WriteLine( strMessage ); That code is encapsulated in a class hierarchy but that is the meat and potatoes of it. My problem is this. MSDN says that the default encoding for creating a file this way is UTF8. And when I write a french character such as é Textpad interprets the file as a UTF 8 file, but notepad++ says it's "ANSI as UTF8" or maybe it's an ansi file but is reading it as UTF8. When I create a file the same way without the french character both textpad and notepad++ read the file as an ansi file even though according to msdn it should be a utf 8 file still. Which program should be trusted. Notepad++ or textpad - Notepad++ seems to be more consistant, but is still the oppossite to what MSDN says it should be. My problem is that we create files that get sent off to another company and depending on whether there are french characters the encoding seems to keep changing. Or is there a better way to determine the encoding of a file. I've read about byte order marks and preambles but as far as I understand neither are guaranteed to be there. We initially thought that all the files we were building were ansi. Also please note that both ansi and utf8 should handle the french characters appropriately as the characters are part of both character sets.

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• Does HDC use alpha channel?

  - by Crend King

  Hello. Is there a way I can determine if an HDC uses alpha channel? I read Question 333559 and Question 685684, but their questions are about BITMAP. Apparently, some HDC has alpha channel (though they may not use it. Call this "Type 1") while others do not ("Type 2"). I know this by doing the following: Given a HDC, Create a compatible DC, and create a DIB section. Select the created HBITMAP into the compatible DC. BitBlt the source HDC to the compatible DC. Now examine the DIB section bits. For type 2 HDC, after every 3 bytes there is a byte always 0 (like 255 255 255 0); for type 1, these bytes are usualy 255 (like 250 240 230 255). To avoid false positive, I memset the bits to all 0x80 prior to the calls. Use GetDIBits directly on the source HDC, specify the HBITMAP as GetCurrentObject(hdc, OBJ_BITMAP). For both types of HDC, the 4th bytes are always 0. Change the DC bitmap by calling ExtTextOut. For type 2, ExtTextOut always set the 4th bytes to 0. For type 1, ExtTextOut always leave them untouched. I also noticed that the source HDC that are created by APIs (CreateCompatibleDC(), BeginPaint() ...) are always type 2. Type 1 HDC are from standard controls (like menu text). Even the HDC I CreateCompatibleDC from a type 1 becomes a type 2. So, on one hand, I'm frustrated that Microsoft does not provide equal information to developers (another example may be that you cannot know the direction of a HBITMAP after it is created), on the other hand, I'm still wondering is there a way to distinguish these HDC. Thanks for help.

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• Need help making a check statement to make sure al the controls are not blank

  - by Michael Quiles

  This is for a tic tac toe game. I need help making a check statement to see if all the controls' Texts are non-blank, and if they are, you have a draw (if someone had won the previous code would have discovered that). Can you give me a good example using my code. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Drawing; namespace MyGame { public class Result1 { static private int[,] Winners = new int[,] { // main gameplay Ex: if x is on 0,1,2 x is the winner {0,1,2}, {3,4,5}, {6,7,8}, {0,3,6}, {1,4,7}, {2,5,8}, {0,4,8}, {2,4,6}, }; static public bool CheckWinner(Button[] myControls) { //bolean statement to check for the winner bool gameOver = false; for (int i = 0; i < 8; i++) { int a = Winners[i, 0]; int b = Winners[i, 1]; int c = Winners[i, 2]; Button b1 = myControls[a], b2 = myControls[b], b3 = myControls[c]; if (b1.Text == "" || b2.Text == "" || b3.Text == "") continue; if (b1.Text == b2.Text && b2.Text == b3.Text) { b1.BackColor = b2.BackColor = b3.BackColor = Color.LightCoral; b1.Font = b2.Font = b3.Font = new System.Drawing.Font("Microsoft Sans Serif", 32F, System.Drawing.FontStyle.Italic & System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0))); gameOver = true; xWinnerForm xWinnerForm = new xWinnerForm(); xWinnerForm.ShowDialog(); //only works with show not showDialog method gets overloaded (b1.Text + " is the Winner"); to get around this I added and image showing the last player } } return gameOver; } } }

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• Is the Cloud ready for an Enterprise Java web application? Seeking a JEE hosting advice.

  - by Jakub Holý

  Greetings to all the smart people around here! I'd like to ask whether it is feasible or a good idea at all to deploy a Java enterprise web application to a Cloud such as Amazon EC2. More exactly, I'm looking for infrastructure options for an application that shall handle few hundred users with long but neither CPU nor memory intensive sessions. I'm considering dedicated servers, virtual private servers (VPSs) and EC2. I've noticed that there is a project called JBoss Cloud so people are working on enabling such a deployment, on the other hand it doesn't seem to be mature yet and I'm not sure that the cloud is ready for this kind of applications, which differs from the typical cloud-based applications like Twitter. Would you recommend to deploy it to the cloud? What are the pros and cons? The application is a Java EE 5 web application whose main function is to enable users to compose their own customized Product by combining the available Parts. It uses stateless and stateful session beans and JPA for persistence of entities to a RDBMS and fetches information about Parts from the company's inventory system via a web service. Aside of external users it's used also by few internal ones, who are authenticated against the company's LDAP. The application should handle around 300-400 concurrent users building their product and should be reasonably scalable and available though these qualities are only of a medium importance at this stage. I've proposed an architecture consisting of a firewall (FW) and load balancer supporting sticky sessions and https (in the Cloud this would be replaced with EC2's Elastic Load Balancing service and FW on the app. servers, in a physical architecture the load-balancer would be a HW), then two physical clustered application servers combined with web servers (so that if one fails, a user doesn't loose his/her long built product) and finally a database server. The DB server would need a slave backup instance that can replace the master instance if it fails. This should provide reasonable availability and fault tolerance and provide good scalability as long as a single RDBMS can keep with the load, which should be OK for quite a while because most of the operations are done in the memory using a stateful bean and only occasionally stored or retrieved from the DB and the amount of data is low too. A problematic part could be the dependency on the remote inventory system webservice but with good caching of its outputs in the application it should be OK too. Unfortunately I've only vague idea of the system resources (memory size, number and speed of CPUs/cores) that such an "average Java EE application" for few hundred users needs. My rough and mostly unfounded estimate based on actual Amazon offerings is that 1.7GB and a single, 2-core "modern CPU" with speed around 2.5GHz (the High-CPU Medium Instance) should be sufficient for any of the two application servers (since we can handle higher load by provisioning more of them). Alternatively I would consider using the Large instance (64b, 7.5GB RAM, 2 cores at 1GHz) So my question is whether such a deployment to the cloud is technically and financially feasible or whether dedicated/VPS servers would be a better option and whether there are some real-world experiences with something similar. Thank you very much! /Jakub Holy PS: I've found the JBoss EAP in a Cloud Case Study that shows that it is possible to deploy a real-world Java EE application to the EC2 cloud but unfortunately there're no details regarding topology, instance types, or anything :-(

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• Reading from serial port with Boost Asio?

  - by trikri

  Hi! I'm going to check for incoming messages (data packages) on the serial port, using Boost Asio. Each message will start with a header that is one byte long, and will specify which type of the message has been sent. Each different type of message has an own length. The function I'm about to write should check for new incoming messages continually, and when it finds one it should read it, and then some other function should parse it. I thought that the code might look something like this: void check_for_incoming_messages() { boost::asio::streambuf response; boost::system::error_code error; std::string s1, s2; if (boost::asio::read(port, response, boost::asio::transfer_at_least(0), error)) { s1 = streambuf_to_string(response); int msg_code = s1[0]; if (msg_code < 0 || msg_code >= NUM_MESSAGES) { // Handle error, invalid message header } if (boost::asio::read(port, response, boost::asio::transfer_at_least(message_lengths[msg_code]-s1.length()), error)) { s2 = streambuf_to_string(response); // Handle the content of s1 and s2 } else if (error != boost::asio::error::eof) { throw boost::system::system_error(error); } } else if (error != boost::asio::error::eof) { throw boost::system::system_error(error); } } Is boost::asio::streambuf is the right thing to use? And how do I extract the data from it so I can parse the message? I also want to know if I need to have a separate thread which only calls this function, so that it get called more often? Isn't there a risk for loosing data in between two calls to the function otherwise, because so much data comes in that it can't be stored in the serial ports memory? I'm using Qt as a widget toolkit and I don't really know how long time it needs to process all it's events.

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• PDF parsing file trailer

  - by Ralph

  It is not clear from the PDF ISO standard document (PDF32000-2008) whether a comment may follow the startxref keyword: startxref Byte_offset_of_last_cross-reference_section %%EOF The standard does seem to imply that comments may appear anywhere: 7.2.3 Comments Any occurrence of the PERCENT SIGN (25h) outside a string or stream introduces a comment. The comment consists of all characters after the PERCENT SIGN and up to but not including the end of the line, including regular, delimiter, SPACE (20h), and HORZONTAL TAB characters (09h). A conforming reader shall ignore comments, and treat them as single white-space characters. That is, a comment separates the token preceding it from the one following it. EXAMPLE The PDF fragment in this example is syntactically equivalent to just the tokens abc and 123. abc% comment ( /%) blah blah blah 123 Comments (other than the %PDF–n.m and %%EOF comments described in 7.5, "File Structure") have no semantics. They are not necessarily preserved by applications that edit PDF files. If they are allowed to appear after the startxref, parsing the file becomes more difficult because you do not know how far to back up from the %%EOF comment to start parsing to find the byte offset. Any ideas?

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• evaluation of a java thread dump

  - by raticulin

  I got a thread dump of one of my processes. It has a bunch of these threads. I guess they are keeping a bunch of memory so I am getting OOM. "Thread-8264" prio=6 tid=0x4c94ac00 nid=0xf3c runnable [0x4fe7f000] java.lang.Thread.State: RUNNABLE at java.util.zip.Inflater.inflateBytes(Native Method) at java.util.zip.Inflater.inflate(Inflater.java:223) - locked <0x0c9bc640 (a java.util.zip.Inflater) at org.apache.commons.compress.archivers.zip.ZipArchiveInputStream.read(ZipArchiveInputStream.java:235) at com.my.ZipExtractorCommonsCompress.extract(ZipExtractorCommonsCompress.java:48) at com.my.CustomThreadedExtractorWrapper$ExtractionThread.run(CustomThreadedExtractorWrapper.java:151) Locked ownable synchronizers: - None "Thread-8241" prio=6 tid=0x4c94a400 nid=0xb8c runnable [0x4faef000] java.lang.Thread.State: RUNNABLE at java.util.zip.Inflater.inflateBytes(Native Method) at java.util.zip.Inflater.inflate(Inflater.java:223) - locked <0x0c36b808 (a java.util.zip.Inflater) at org.apache.commons.compress.archivers.zip.ZipArchiveInputStream.read(ZipArchiveInputStream.java:235) at com.my.ZipExtractorCommonsCompress.extract(ZipExtractorCommonsCompress.java:48) at com.my.CustomThreadedExtractorWrapper$ExtractionThread.run(CustomThreadedExtractorWrapper.java:151) Locked ownable synchronizers: - None I am trying to find out how it arrived to this situation. CustomThreadedExtractorWrapper is a wrapper class that fires a thread to do some work (ExtractionThread, which uses ZipExtractorCommonsCompress to extract zip contents from a compressed stream). If the task is taking too long, ExtractionThread.interrupt(); is called to cancel the operation. I can see in my logs that the cancellation happened 25 times. And I see 21 of these threads in my dump. My questions: What is the status of these threads? Alive and running? Blocked somehow? They did not die with .interrupt() apparently? Is there a sure way to really kill a thread? What does really mean 'locked ' in the stack trace? Line 223 in Inflater.java is: public synchronized int inflate(byte[] b, int off, int len) { ... //return is line 223 return inflateBytes(b, off, len); }

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• Using Sendkeys in python to press {F12} results in other keys pressed?

  - by ThantiK

  import time from ctypes import * import win32gui import win32com.client as comclt X = 119 Y = 53 def PILColorToRGB(pil_color): """ convert a PIL-compatible integer into an (r, g, b) tuple """ hexstr = '%06x' % pil_color # reverse byte order r, g, b = hexstr[4:], hexstr[2:4], hexstr[:2] r, g, b = [int(n, 16) for n in (r, g, b)] return (r, g, b) wsh = comclt.Dispatch("WScript.Shell") w = win32gui user = windll.LoadLibrary("c:\\windows\\system32\\user32.dll") h = user.GetDC(0) gdi = windll.LoadLibrary("c:\\windows\\system32\\gdi32.dll") while True: FG = w.GetWindowText(w.GetForegroundWindow()) #FG = Foreground window title. if FG == "World of Warcraft": rgb = (PILColorToRGB(gdi.GetPixel(h,X,Y))) #X, Y time.sleep(0.333) #don't check too often. if (rgb[0] >= 130): #While Pixel (X, Y) is Red... #print "%d %d %d" % (rgb[0], rgb[1], rgb[2]) #Debug wsh.SendKeys("{F12}") #Send a key. time.sleep(0.7) #Add some extra down-time if we send the key. else: time.sleep(5) Basically all this code does is read a pixel on the screen, and send a key (F12) if the pixel is red. But when using this code I regularly get some phantom key-code being pressed. The application I'm using this on is obviously world of warcraft, and I have checked that all keybinds are standard keybinds. However randomly it seems I get either an up arrow, or a w pressed, which moves my character forward whenever this code executes (F12 is bound to a macro, unbound from any movement. If I press f12 with a hardware event, it does not exhibit this behavior. What in the world could be going on here?

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• Segment register, IP register and memory addressing issue!

  - by Zia ur Rahman

  In the following text I asked two questions and I also described that what I know about these question so that you can understand my thinking. Your precious comments about the below text are required. Below is the Detail of 1ST Question As we know that if we have one mega byte memory then we need 20 bits to address this memory. Another thing is each memory cell has a physical address which is of 20 bits in 1Mb memory. IP register in IAPX88 is of 16 bits. Now my point of view is, we can not access the memory at all by the IP register because the memory need 20 bit address to be addressed but the IP register is of 16 bits. If we have a memory of 64k then IP register can access this memory because this memory needs 16 bits to be addressed. But incase of 1mb memory IP can’t.tell me am i right or not if not why? Suppose physical address of memory is 11000000000000000101 Now how can we access this memory location by 16 bits. Below is the detail of Next Question: My next question is , suppose IP register is pointing to memory location, and the segment register is also pointing to a memory location (start of the segment), the memory is of 1MB, how we can access a memory location by these two 16 bit registers tell me the sequence of steps how the 20 bits addressable memory location is accessed . If your answer is, we take the segment value and we shift it left by 4 bits and then add the IP value into it to get the 20 bits address, then this raises another question that is the address bus (the address bus should be 20 bits wide), the registers both the segment register and the IP register are of 16 bits each , now if address bus is 20 bits wide then this means that the address bus is connected to both these registers. If its not the case then another thing that comes into my mind is that both these registers generate a 20 bit address and there would be a register which can store 20 bits and this register would be connected to both these register and the address bus as well.

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• This property cannot be set after writing has started! on a C# WebRequest Object

  - by EBAGHAKI

  I want to reuse a WebRequest object so that cookies and session would be saved for later request to the server. Below is my code. If i use Post function twice on the second time at request.ContentLength = byteArray.Length; it will throw an exception This property cannot be set after writing has started! But as you can see dataStream.Close(); Should close the writing process! Anybody knows what's going on? static WebRequest request; public MainForm() { request = WebRequest.Create("http://localhost/admin/admin.php"); } static string Post(string url, string data) { request.Method = "POST"; byte[] byteArray = Encoding.UTF8.GetBytes(data); request.ContentType = "application/x-www-form-urlencoded"; request.ContentLength = byteArray.Length; Stream dataStream = request.GetRequestStream(); dataStream.Write(byteArray, 0, byteArray.Length); dataStream.Close(); WebResponse response = request.GetResponse(); Console.WriteLine(((HttpWebResponse)response).StatusDescription); dataStream = response.GetResponseStream(); StreamReader reader = new StreamReader(dataStream); string responseFromServer = reader.ReadToEnd(); Console.WriteLine(responseFromServer); reader.Close(); dataStream.Close(); response.Close(); request.Abort(); return responseFromServer; }

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• Receiving broadcast messages

  - by Prasad

  Hi, I'm trying to receive broadcast messages using C# code in an ISDN network with BRI interface at my end. I see the packets sent to the broadcast ip address (239.255.255.255) on some ports using Comm View tool. But when I try to listen to this IP address, it says the address is not in a valid context. But when I send broadcast messages to 255.255.255.255 on a port, I can receive those messages with the below code.. What could be the problem with this ip address - 239.255.255.255 ? The code I use to listen to broadcast messages is.. UdpClient udp = new UdpClient(); IPEndPoint receiveEndPoint = new IPEndPoint(IPAddress.Any, 8013); // If I use IPAddress.Parse("239.255.255.255") to listen to, // it says "the address is not in a valid // context." udp.Client.Bind(receiveEndPoint); udp.BeginReceive(_Callback, udp); static private void _Callback(IAsyncResult iar) { try { UdpClient client = (UdpClient)iar.AsyncState; client.BeginReceive(_Callback, client); IPEndPoint ipRemote = new IPEndPoint(IPAddress.Any, 8013); byte[] rgb = client.EndReceive(iar, ref ipRemote); Console.WriteLine("Received {0} bytes: \"{1}\"", rgb.Length.ToString(), Encoding.UTF8.GetString(rgb)); } catch (ObjectDisposedException) { Console.WriteLine("closing listening socket"); } catch (Exception exc) { Console.WriteLine("Listening socket error: \"" + exc.Message + "\""); } } There are packets sent to the broadcast ipaddress (239.255.255.255) which I can see in Commview tool, but can't receive them from the code... Can anybody help me out please? Thanking you in advance, Prasad Kancharla.

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• x86 CMP Instruction Difference

  - by Pindatjuh

  Question What is the (non-trivial) difference between the following two x86 instructions? 39 /r CMP r/m32,r32 Compare r32 with r/m32 3B /r CMP r32,r/m32 Compare r/m32 with r32 Background I'm building a Java assembler, which will be used by my compiler's intermediate language to produce Windows-32 executables. Currently I have following code: final ModelBase mb = new ModelBase(); // create new memory model mb.addCode(new Compare(Register.ECX, Register.EAX)); // add code mb.addCode(new Compare(Register.EAX, Register.ECX)); // add code final FileOutputStream fos = new FileOutputStream(new File("test.exe")); mb.writeToFile(fos); fos.close(); To output a valid executable file, which contains two CMP instruction in a TEXT-section. The executable outputted to "text.exe" will do nothing interesting, but that's not the point. The class Compare is a wrapper around the CMP instruction. The above code produces (inspecting with OllyDbg): Address Hex dump Command 0040101F |. 3BC8 CMP ECX,EAX 00401021 |. 3BC1 CMP EAX,ECX The difference is subtle: if I use the 39 byte-opcode: Address Hex dump Command 0040101F |. 39C1 CMP ECX,EAX 00401021 |. 39C8 CMP EAX,ECX Which makes me wonder about their synonymity and why this even exists.

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• C# .Net Serial DataReceived Event response too slow for high-rate data.

  - by Matthew

  Hi, I have set up a SerialDataReceivedEventHandler, with a forms based program in VS2008 express. My serial port is set up as follows: 115200, 8N1 Dtr and Rts enabled ReceivedBytesThreshold = 1 I have a device I am interfacing with over a BlueTooth, USB to Serial. Hyper terminal receives the data just fine at any data rate. The data is sent regularly in 22 byte long packets. This device has an adjustable rate at which data is sent. At low data rates, 10-20Hz, the code below works great, no problems. However, when I increase the data rate past 25Hz, there starts to recieve mulitple packets on one call. What I mean by this is that there should be a event trigger for every incoming packet. With higher output rates, I have tested the buffer size (BytesToRead command) immediatly when the event is called and there are multiple packets in the buffer then. I think that the event fires slowly and by the time it reaches the code, more packes have hit the buffer. One test I do is see how many time the event is trigger per second. At 10Hz, I get 10 event triggers, awesome. At 100Hz, I get something like 40 event triggers, not good. My goal for data rate is 100HZ is acceptable, 200Hz preferred, and 300Hz optimum. This should work because even at 300Hz, that is only 52800bps, less than half of the set 115200 baud rate. Anything I am over looking? public Form1() { InitializeComponent(); serialPort1.DataReceived += new SerialDataReceivedEventHandler(serialPort1_DataReceived); } private void serialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e) { this.Invoke(new EventHandler(Display_Results)); } private void Display_Results(object s, EventArgs e) { serialPort1.Read(IMU, 0, serial_Port1.BytesToRead); }

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• Performance problem with System.Net.Mail

  - by Saif Khan

  I have this unusual problem with mailing from my app. At first it wasn't working (getting unable to relay error crap) anyways I added the proper authentication and it works. My problem now is, if I try to send around 300 emails (each with a 500k attachment) the app starts hanging around 95% thru the process. Here is some of my code which is called for each mail to be sent Using mail As New MailMessage() With mail .From = New MailAddress(My.Resources.EmailFrom) For Each contact As Contact In Contacts .To.Add(contact.Email) Next .Subject = "Accounting" .Body = My.Resources.EmailBody 'Back the stream up to the beginning orelse the attachment 'will be sent as a zero (0) byte file. attachment.Seek(0, SeekOrigin.Begin) .Attachments.Add(New Attachment(attachment, String.Concat(Item.Year, Item.AttachmentType.Extension))) End With Dim smtp As New SmtpClient("192.168.1.2") With smtp .DeliveryMethod = SmtpDeliveryMethod.Network .UseDefaultCredentials = False .Credentials = New NetworkCredential("username", "password") .Send(mail) End With End Using With item .SentStatus = True .DateSent = DateTime.Now.Date .Save() End With Return I was thinking, can I just prepare all the mails and add them to a collection then open one SMTP conenction and just iterate the collection, calling the send like this Using mail As New MailMessage() ... MailCollection.Add(mail) End Using ... Dim smtp As New SmtpClient("192.168.1.2") With smtp .DeliveryMethod = SmtpDeliveryMethod.Network .UseDefaultCredentials = False .Credentials = New NetworkCredential("username", "password") For Each mail in MainCollection .Send(mail) Next End With

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• c#: how to read parts of a file? (DICOM)

  - by Xaisoft

  I would like to read a DICOM file in C#. I don't want to do anything fancy, I just for now would like to know how to read in the elements, but first I would actually like to know how to read the header to see if is a valid DICOM file. It consists of Binary Data Elements. The first 128 bytes are unused (set to zero), followed by the string 'DICM'. This is followed by header information, which is organized into groups. A sample DICOM header First 128 bytes: unused DICOM format. Followed by the characters 'D','I','C','M' Followed by extra header information such as: 0002,0000, File Meta Elements Groups Len: 132 0002,0001, File Meta Info Version: 256 0002,0010, Transfer Syntax UID: 1.2.840.10008.1.2.1. 0008,0000, Identifying Group Length: 152 0008,0060, Modality: MR 0008,0070, Manufacturer: MRIcro In the above example, the header is organized into groups. The group 0002 hex is the file meta information group which contains 3 elements: one defines the group length, one stores the file version and the their stores the transfer syntax. Questions How to I read the header file and verify if it is a DICOM file by checking for the 'D','I','C','M' characters after the 128 byte preamble? How do I continue to parse the file reading the other parts of the data?

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• Winforms: How to speed up Invalidate()?

  - by Pedery

  I'm developing a retained mode drawing application in GDI+. The application can draw simple shapes to a canvas and perform basic editing. The math that does this is optimized to the last byte and is not an issue. I'm drawing on a panel that is using the built-in Controlstyles.DoubleBuffer. Now, my problem arises if I run my app maximized on a big monitor (HD in my case). If I try to draw a line from one corner of the (big) canvas to the diagonally oposite other, it will start to lag and the CPU goes high up. Each graphical object in my app has a boundingbox. Thus, when I invalidate the boundingbox of a line that goes from one corner of the maximized app to the oposite diagonal one, that boundingbox is virtually as big as the canvas. When a user is drawing a line, this invalidation of the boundingbox thus happens on the mousemove event, and there is a clear lag visible. This lag also exists if the line is the only object on the canvas. I've tried to optimize this in many ways. If I draw a shorter line, the CPU and the lag goes down. If I remove the Invalidate() and keep all other code, the app is quick. If I use a Region (that only spans the figure) to invalidate instead of the boundingbox, it is just as slow. If I split the boundingbox into a range of smaller boxes that lie back to back, thus reducing the invalidation area, no visible performance gain can be seen. Thus I'm at a loss here. How can I speed up the invalidation? On a side note, both Paint.Net and Mspaint suffers from the same shortcommings. Word and PowerPoint however, seem to be able to paint a line as described above with no lag and no CPU load at all. Thus it's possible to achieve the desired results, the question is how?

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• Why so much stack space used for each recursion?

  - by Harvey

  I have a simple recursive function RCompare() that calls a more complex function Compare() which returns before the recursive call. Each recursion level uses 248 bytes of stack space which seems like way more than it should. Here is the recursive function: void CMList::RCompare(MP n1) // RECURSIVE and Looping compare function { auto MP ne=n1->mf; while(StkAvl() && Compare(n1=ne->mb)) RCompare(n1); // Recursive call ! } StkAvl() is a simple stack space check function that compares the address of an auto variable to the value of an address near the end of the stack stored in a static variable. It seems to me that the only things added to the stack in each recursion are two pointer variables (MP is a pointer to a structure) and the stuff that one function call stores, a few saved registers, base pointer, return address, etc., all 32-bit (4 byte) values. There's no way that is 248 bytes is it? I don't no how to actually look at the stack in a meaningful way in Visual Studio 2008. Thanks

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