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• Getting the Item Count of a large sharepoint list in fastest way

  - by sooraj

  I am trying to get the count of the items in a sharepoint document library programatically. The scale I am working with is 30-70000 items. We have usercontrol in a smartpart to display the count . Ours is a TEAM site. This is the code to get the total count SPList VoulnterrList = web.Lists[ListTitle]; SPQuery query = new SPQuery(); query.ViewAttributes = "Scope=\"Recursive\""; string queries = "<Where><Eq><FieldRef Name='ApprovalStatus' /><Value Type='Choice'>Pending</Value></Eq></Where>"; query.Query = queries; SPListItemCollection lstitemcollAssoID = VoulnterrList.GetItems(query); lblCount.Text = "Total Proofs: " + VoulnterrList.Items.Count.ToString() + " Pending Proofs: " + lstitemcollAssoID.Count.ToString(); The problem is this has serious performance issue it takes 75 to 80 sec to load the page. if we comment this page load will decrees to 4 sec. Any better approch for this problem Ours is sharepoint 2007

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• Merging two arrays in PHP

  - by Industrial

  Hi everyone, I am trying to create a new array from two current arrays. Tried array_merge, but it will not give me what I want. $array1 is a list of keys that I pass to a function. $array2 holds the results from that function, but doesn't contain any non-available resuls for keys. So, I want to make sure that all requested keys comes out with 'null':ed values, as according to the shown $result array. It goes a little something like this: $array1 = array('item1', 'item2', 'item3', 'item4'); $array2 = array( 'item1' => 'value1', 'item2' => 'value2', 'item3' => 'value3' ); Here's the result I want: $result = array( 'item1' => 'value1', 'item2' => 'value2', 'item3' => 'value3', 'item4' => '' ); It can be done this way, but I don't think that it's a good solution - I really don't like to take the easy way out and suppress PHP errors by adding @:s in the code. This sample would obviously throw errors since 'item4' is not in $array2, based on the example. foreach ($keys as $k => $v){ @$array[$v] = $items[$v]; } So, what's the fastest (performance-wise) way to accomplish the same result?

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• class selector refuses after append to body

  - by supersize

  I'm appending loads of divs in a wrapper: var cubes = [], allCubes = '', for(var i = 0; i < 380; i++) { var randomleft = Math.floor(Math.random()*Math.floor(Math.random()*1000)), randomtop = Math.floor(Math.random()*Math.floor(Math.random()*1000)); allCubes += '<div id="cube'+i+'" class="cube" style="position: absolute; border: 2px #000 solid; left: '+randomleft+'px; top: '+randomtop+'px; width: 9px; height: 9px; z-index: -1"></div>'; } $('#wrapper').append(allCubes); // performance for(var i = 0; i < 380; i++) { cubes.push($('#cube'+i)); } and then I would like to make them all draggable with jQueryUI and log their current position. var allc = $('.cube'); allc.draggable().on('mouseup', function(i) { allc.each(function() { var nleft = $(this).offset().left; var ntop = $(this).offset().top; console.log('cubes['+i+'].animate({ left:'+nleft+',top:'+ntop+'})'); }); }); Unfortunenately it does not work. They are neither draggable nor there comes up a log. Thanks

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• Best way to keep a .net client app updated with status of another application

  - by rwmnau

  I have a Windows service that's running all the time, and takes some action every 15 minutes. I also have a client WinForms app that displays some information about what the service is doing. I'd like the forms application to keep itself updated with a recent status, but I'm not sure if polling every second is a good move performance-wise. When it starts, my Windows Service opens a WCF named pipe to receive queries (from my client form) Every second, a timer on the winform sends a query to the pipe, and then displays the results. If the pipe isn't there, the form displays that the service isn't running. Is that the best way to do this? If my service opens the pipe when it starts, will it always stay open (until I close it or my service stops)? In addition to polling the service, maybe there's some way for the service to notify any watching applications of certain events, like starting and stopping processing? That way, I could poll less, since I'd presumably know about big events already, and would only be polling for progress. Anything that I'm missing?

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• Tracking down origin of I/O in multi-process server

  - by Craig Ringer

  I'm currently trying to track down some phantom I/O in a PostgreSQL build I'm testing. It's a multi-process server and it isn't simple to associate disk I/O back to a particular back-end and query. I thought Linux's perf tool would be ideal for this, but I'm struggling to capture block I/O performance counter metrics and associate them with user-space activity. It's easy to record block I/O requests and completions with, eg: sudo perf record -g -T -u postgres -e 'block:block_rq_*' and the user-space pid is recorded, but there's no kernel or user-space stack captured, or ability to snapshot bits of the user-space process's heap (say, query text) etc. So while you have the pid, you don't know what the process was doing at that point. Just perf script output like: postgres 7462 [002] 301125.113632: block:block_rq_issue: 8,0 W 0 () 208078848 + 1024 [postgres] If I add the -g flag to perf record it'll take snapshots of the kernel stack, but doesn't capture user-space state for perf events captured in the kernel. The user-space stack only goes up to the entry-point from userspace, like LWLockRelease, LWLockAcquire, memcpy (mmap'd IO), __GI___libc_write, etc. So. Any tips? Being able to capture a snapshot of the user-space stack in response to kernel events would be ideal.

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• Planning a programming project by example (C# or C++)

  - by Lunan

  I am in the last year of undergraduate degree and i am stumped by the lack of example in c++ and c# large project in my university. All the mini project and assignment are based on text based database, which is so inefficient, and console display and command, which is frustrating. I want to develop a complete prototype of corporate software which deals in Inventory, Sales, Marketing, etc. Everything you would usually find in SAP. I am grateful if any of you could direct me to a books or article or sample program. Some of the question are : How to plan for this kind of programming? should i use the concept of 1 object(such as inventory) have its own process and program and have an integrator sit for all the program, or should i integrate it in 1 big program? How to build and address a database? i have little bit knowledge in database and i know SQL but i never address database in a program before. Database are table, and how do you suppose to represent a table in a OOP way? For development type, which is better PHP and C++ or C# and ASP.NET? I am planning to use Web Interface to set form and information, but using a background program to handle the compute. .NET is very much integrated and coding should be much faster, but i really wonder about performance if compared to PHP and C++ package thank you for the info

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• Aliasing `T*` with `char*` is allowed. Is it also allowed the other way around?

  - by StackedCrooked

  Note: This question has been renamed and reduced to make it more focused and readable. Most of the comments refer to the old text. According to the standard objects of different type may not share the same memory location. So this would not be legal: int i = 0; short * s = reinterpret_cast<short*>(&i); // BAD! The standard however allows an exception to this rule: any object may be accessed through a pointer to char or unsigned char: int i = 0; char * c = reinterpret_cast<char*>(&i); // OK However, it is not clear to me if this is also allowed the other way around. For example: char * c = read_socket(...); unsigned * u = reinterpret_cast<unsigned*>(c); // huh? Summary of the answers The answer is NO for two reasons: You an only access an existing object as char*. There is no object in my sample code, only a byte buffer. The pointer address may not have the right alignment for the target object. In that case dereferencing it would result in undefined behavior. On the Intel and AMD platforms it will result performance overhead. On ARM it will trigger a CPU trap and your program will be terminated! This is a simplified explanation. For more detailed information see answers by @Luc Danton, @Cheers and hth. - Alf and @David Rodríguez.

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• C Population Count of unsigned 64-bit integer with a maximum value of 15

  - by BitTwiddler1011

  I use a population count (hamming weight) function intensively in a windows c application and have to optimize it as much as possible in order to boost performance. More than half the cases where I use the function I only need to know the value to a maximum of 15. The software will run on a wide range of processors, both old and new. I already make use of the POPCNT instruction when Intel's SSE4.2 or AMD's SSE4a is present, but would like to optimize the software implementation (used as a fall back if no SSE4 is present) as much as possible. Currently I have the following software implementation of the function: inline int population_count64(unsigned __int64 w) { w -= (w 1) & 0x5555555555555555ULL; w = (w & 0x3333333333333333ULL) + ((w 2) & 0x3333333333333333ULL); w = (w + (w 4)) & 0x0f0f0f0f0f0f0f0fULL; return int(w * 0x0101010101010101ULL) 56; } So to summarize: (1) I would like to know if it is possible to optimize this for the case when I only want to know the value to a maximum of 15. (2) Is there a faster software implementation (for both Intel and AMD CPU's) than the function above?

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• Domain model for an online WYSYWG webpage generator / runtime

  - by CharlieBrown

  Hi all, I'm using C#, MVC, NHibernate and StructureMap as my IoC container, and need some ideas regarding my domain model. The application I'm working has two parts: an Authoring part and a Runtime part. The idea is to allow the user to create a webpage in Authoring (mostly a form actually) by choosing from a set of predefined controls. That webpage will be later used as a form in a call center environment (Runtime part), or may be used in an intranet portal, etc. Basically something similar to what a CMS would do. The difference is, of course, that the webpage/form the author generates will be used and fulfilled in runtime, and that authros should be able to freely create the webpage they want without limitations. I have a draft working model that allows a RunController to iterate over the ScriptPage (my class for the "generated webpage") Controls collection and uses partial views to render each of them. Works kind of fine. Basically I have a common ScriptControl class, and then I can create for example a TextInputControl or a DropDownControl by inheriting from that base class. I can also figure out the Authoring part of the app, although that will surely be fun in itself for sure. :) The biggest problem I have now is persistance. In order to be flexible, I want to be able to add more controls, and template controls (think of an Address composite control) in sepparate DLLs, so I think having a relational model that handles very possible control is not the way to go. My current thinking is using a kind of ObjectStore: binary-serializing the ScriptPage object that contains the List collection and deserializing at Runtime, but I'm not sure how good will it work with NHibernate and how good the performance will be. Serializing a small "page" with 10 controls results in 7964 bytes, for example. Any ideas out there? Thanks in advance, excuse the length. ;)

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• How to get a category listing from Magento?

  - by alex

  I want to create a page in Magento that shows a visual representation of the categories.. example CATEGORY product 1 product 2 ANOTHER CATEGORY product 3 My problem is, their database is organised very differently to what I've seen in the past. They have tables dedicated to data types like varchar, int, etc. I assume this is for performance or similiar. I haven't found a way to use MySQL to query the database and get a list of categories. I'd then like to match these categories to products, to get a listing of products for each category. Unfortunately Magento seems to make this very difficult. Also I have not found a method that will work from within a page block.. I have created showcase.phtml and put it in the XML layout and it displays and runs it's PHP code. I was hoping for something easy like looping through $this-getAllCategories(); and then a nested loop inside with something like $category-getChildProducts(); Can anyone help me? Thank you!

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• Is there a set based solution for this problem?

  - by NYSystemsAnalyst

  We have a table set up as follows: |ID|EmployeeID|Date |Category |Hours| |1 |1 |1/1/2010 |Vacation Earned|2.0 | |2 |2 |2/12/2010|Vacation Earned|3.0 | |3 |1 |2/4/2010 |Vacation Used |1.0 | |4 |2 |5/18/2010|Vacation Earned|2.0 | |5 |2 |7/23/2010|Vacation Used |4.0 | The business rules are: Vacation balance is calculated by vacation earned minus vacation used. Vacation used is always applied against the oldest vacation earned amount first. We need to return the rows for Vacation Earned that have not been offset by vacation used. If vacation used has only offset part of a vacation earned record, we need to return that record showing the difference. For example, using the above table, the result set would look like: |ID|EmployeeID|Date |Category |Hours| |1 |1 |1/1/2010 |Vacation Earned|1.0 | |4 |2 |5/18/2010|Vacation Earned|1.0 | Note that record 2 was eliminated because it was completely offset by used time, but records 1 and 4 were only partially used, so they were calculated and returned as such. The only way we have thought of to do this is to get all of the vacation earned records in a temporary table. Then, get the total vacation used and loop through the temporary table, deleting the oldest record and subtracting that value from the total vacation used until the total vacation used is zero. We could clean it up for when the remaining vacation used is only part of the oldest vacation earned record. This would leave us with just the outstanding vacation earned records. This works, but it is very inefficient and performs poorly. Also, the performance will just degrade over time as more and more records are added. Are there any suggestions for a better solution, preferable set based? If not, we'll just have to go with this.

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• VB6 Game Development : Don't ask me why :-)

  - by CVS-2600Hertz-wordpress-com

  Hi All, I am developing a game in VB6 (plz don't ask me why :) ). The storyboard is ready and a rough implementation is underway. I am following a "pure-software-rendering" approach. (i.e. no DirectX, no openGL etc.) Amongst many others, the following "serious" problems exist: 2D alpha transparency reqd. to implement overlays. Parallax implementation to give depth-of-field illusion. Capturing mouse-scroll events globally (as in FPS-es; mapping them to changing weapon). Async sound play with absolute "zero-lag". Any ideas anyone. Please suggest any well documented library/ocx or sample-code. Plz do provide solutions with max performance and with as little overhead as possible. Also, anyone who has developed any games, and would be open to sharing her/his code would be highly appreciated. (any well-acknowledged VB games whose source-code i can study??) Thank You

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• Faster way to convert from a String to generic type T when T is a valuetype?

  - by Kumba

  Does anyone know of a fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type? This is too slow for my taste: Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T) But it seems to be the only sane method of getting from a String -- T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned. I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use. It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?

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• Color banding only on Android 4.0+

  - by threeshinyapples

  On emulators running Android 4.0 or 4.0.3, I am seeing horrible colour banding which I can't seem to get rid of. On every other Android version I have tested, gradients look smooth. I have a SurfaceView which is configured as RGBX_8888, and the banding is not present in the rendered canvas. If I manually dither the image by overlaying a noise pattern at the end of rendering I can make the gradients smooth again, though obviously at a cost to performance which I'd rather avoid. So the banding is being introduced later. I can only assume that, on 4.0+, my SurfaceView is being quantized to a lower bit-depth at some point between it being drawn and being displayed, and I can see from a screen capture that gradients are stepping 8 values at a time in each channel, suggesting a quantization to 555 (not 565). I added the following to my Activity onCreate function, but it made no difference. getWindow().setFormat(PixelFormat.RGBA_8888); getWindow().addFlags(WindowManager.LayoutParams.FLAG_DITHER); I also tried putting the above in onAttachedToWindow() instead, but there was still no change. (I believe that RGBA_8888 is the default window format anyway for 2.2 and above, so it's little surprise that explicitly setting that format has no effect on 4.0+.) Which leaves the question, if the source is 8888 and the destination is 8888, what is introducing the quantization/banding and why does it only appear on 4.0+? Very puzzling. I wonder if anyone can shed some light?

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• Java: multi-threaded maps: how do the implementations compare?

  - by user346629

  I'm looking for a good hash map implementation. Specifically, one that's good for creating a large number of maps, most of them small. So memory is an issue. It should be thread-safe (though losing the odd put might be an OK compromise in return for better performance), and fast for both get and put. And I'd also like the moon on a stick, please, with a side-order of justice. The options I know are: HashMap. Disastrously un-thread safe. ConcurrentHashMap. My first choice, but this has a hefty memory footprint - about 2k per instance. Collections.sychronizedMap(HashMap). That's working OK for me, but I'm sure there must be faster alternatives. Trove or Colt - I think neither of these are thread-safe, but perhaps the code could be adapted to be thread safe. Any others? Any advice on what beats what when? Any really good new hash map algorithms that Java could use an implementation of? Thanks in advance for your input!

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• Database solution for 200million writes/day, monthly summarization queries

  - by sb

  Hello. I'm looking for help deciding on which database system to use. (I've been googling and reading for the past few hours; it now seems worthwhile to ask for help from someone with firsthand knowledge.) I need to log around 200 million rows (or more) per 8 hour workday to a database, then perform weekly/monthly/yearly summary queries on that data. The summary queries would be for collecting data for things like billing statements, eg. "How many transactions of type A did each user run this month?" (could be more complex, but that's the general idea). I can spread the database amongst several machines, as necessary, but I don't think I can take old data offline. I'll definitely need to be able to query a month's worth of data, maybe a year. These queries would be for my own use, and wouldn't need to be generated in real-time for an end-user (they could run overnight, if needed). Does anyone have any suggestions as to which databases would be a good fit? P.S. Cassandra looks like it would have no problem handling the writes, but what about the huge monthly table scans? Is anyone familiar with Cassandra/Hadoop MapReduce performance?

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• Adding variably named fields to Python classes

  - by Carson Myers

  I have a python class, and I need to add an arbitrary number of arbitrarily long lists to it. The names of the lists I need to add are also arbitrary. For example, in PHP, I would do this: class MyClass { } $c = new MyClass(); $n = "hello" $c.$n = array(1, 2, 3); How do I do this in Python? I'm also wondering if this is a reasonable thing to do. The alternative would be to create a dict of lists in the class, but since the number and size of the lists is arbitrary, I was worried there might be a performance hit from this. If you are wondering what I'm trying to accomplish, I'm writing a super-lightweight script interpreter. The interpreter walks through a human-written list and creates some kind of byte-code. The byte-code of each function will be stored as a list named after the function in an "app" class. I'm curious to hear any other suggestions on how to do this as well.

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• How security of the systems might be improved using database procedures?

  - by Centurion

  The usage of Oracle PL/SQL procedures for controlling access to data often emphasized in PL/SQL books and other sources as being more secure approach. I'v seen several systems where all business logic related with data is performed through packages, procedures and functions, so application code becomes quite "dumb" and is only responsible for visualization part. I even heard some devs call such approaches and driving architects as database nazi :) because all logic code resides in database. I do know about DB procedure performance benefits, but now I'm interested in a "better security" when using thick client model. I assume such design mostly used when Oracle (and maybe MS SQL Server) databases are used. I do agree such approach improves security but only if there are not much users and every system user has a database account, so we might control and monitor data access through standard database user security. However, how such approach could increase the security for an average web system where thick clients are used: for example one database user with DML grants on all tables, and other users are handled using "users" and"user_rights" tables? We could use DB procedures, save usernames into context use that for filtering but vulnerability resides at the root - if the main database account is compromised than nothing will help. Of course in a real system we might consider at least several main users (for example frontend_db_user, backend_db_user).

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• Is there a Java data structure that is effectively an ArrayList with double indicies and built-in in

  - by Bob Cross

  I am looking for a pre-built Java data structure with the following characteristics: It should look something like an ArrayList but should allow indexing via double-precision rather than integers. Note that this means that it's likely that you'll see indicies that don't line up with the original data points (i.e., asking for the value that corresponds to key "1.5"). As a consequence, the value returned will likely be interpolated. For example, if the key is 1.5, the value returned could be the average of the value at key 1.0 and the value at key 2.0. The keys will be sorted but the values are not ensured to be monotonically increasing. In fact, there's no assurance that the first derivative of the values will be continuous (making it a poor fit for certain types of splines). Freely available code only, please. For clarity, I know how to write such a thing. In fact, we already have an implementation of this and some related data structures in legacy code that I want to replace due to some performance and coding issues. What I'm trying to avoid is spending a lot of time rolling my own solution when there might already be such a thing in the JDK, Apache Commons or another standard library. Frankly, that's exactly the approach that got this legacy code into the situation that it's in right now.... Is there such a thing out there in a freely available library?

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• Iterate over defined elements of a JS array

  - by sibidiba

  I'm using a JS array to Map IDs to actual elements, i.e. a key-value store. I would like to iterate over all elements. I tried several methods, but all have its caveats: for (var item in map) {...} Does iterates over all properties of the array, therefore it will include also functions and extensions to Array.prototype. For example someone dropping in the Prototype library in the future will brake existing code. var length = map.lenth; for (var i = 0; i < length; i++) { var item = map[i]; ... } does work but just like $.each(map, function(index, item) {...}); They iterate over the whole range of indexes 0..max(id) which has horrible drawbacks: var x = []; x[1]=1; x[10]=10; $.each(x, function(i,v) {console.log(i+": "+v);}); 0: undefined 1: 1 2: undefined 3: undefined 4: undefined 5: undefined 6: undefined 7: undefined 8: undefined 9: undefined 10: 10 Of course my IDs wont resemble a continuous sequence either. Moreover there can be huge gaps between them so skipping undefined in the latter case is unacceptable for performance reasons. How is it possible to safely iterate over only the defined elements of an array (in a way that works in all browsers and IE)?

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• Setting pixel values in Nvidia NPP ImageCPU objects?

  - by solvingPuzzles

  In the Nvidia Performance Primitives (NPP) image processing examples in the CUDA SDK distribution, images are typically stored on the CPU as ImageCPU objects, and images are stored on the GPU as ImageNPP objects. boxFilterNPP.cpp is an example from the CUDA SDK that uses these ImageCPU and ImageNPP objects. When using a filter (convolution) function like nppiFilter, it makes sense to define a filter as an ImageCPU object. However, I see no clear way setting the values of an ImageCPU object. npp::ImageCPU_32f_C1 hostKernel(3,3); //allocate space for 3x3 convolution kernel //want to set hostKernel to [-1 0 1; -1 0 1; -1 0 1] hostKernel[0][0] = -1; //this doesn't compile hostKernel(0,0) = -1; //this doesn't compile hostKernel.at(0,0) = -1; //this doesn't compile How can I manually put values into an ImageCPU object? Notes: I didn't actually use nppiFilter in the code snippet; I'm just mentioning nppiFilter as a motivating example for writing values into an ImageCPU object. The boxFilterNPP.cpp example doesn't involve writing directly to an ImageCPU object, because nppiFilterBox is a special case of nppiFilter that uses a built-in gaussian smoothing filter (probably something like [1 1 1; 1 1 1; 1 1 1]).

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• Please tell me what is wrong with my threading!!!

  - by kiddo

  I have a function where I will compress a bunch of files into a single compressed file..it is taking a long time(to compress),so I tried implementing threading in my application..Say if I have 20 files for compression,I separated that as 5*4=20,inorder to do that I have separate variables(which are used for compression) for all 4 threads in order to avoid locks and I will wait until the 4 thread finishes..Now..the threads are working but i see no improvement in their performance..normally it will take 1 min for 20 files(for example) after implementing threading ...there is only 5 or 3 sec difference., sometimes the same. here i will show the code for 1 thread(so it is for other3 threads) //main thread myClassObject->thread1 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction1,myClassObject); .... HANDLE threadHandles[4]; threadHandles[0] = myClassObject->thread1->m_hThread; .... WaitForSingleObject(myClassObject->thread1->m_hThread,INFINITE); UINT MyThreadFunction(LPARAM lparam) { CMerger* myClassObject = (CMerger*)lparam; CString outputPath = myClassObject->compressedFilePath.GetAt(0);//contains the o/p path wchar_t* compressInputData[] = {myClassObject->thread1outPath, COMPRESS,(wchar_t*)(LPCTSTR)(outputPath)}; HINSTANCE loadmyDll; loadmydll = LoadLibrary(myClassObject->thread1outPath); fp_Decompress callCompressAction = NULL; int getCompressResult=0; myClassObject->MyCompressFunction(compressInputData,loadClient7zdll,callCompressAction,myClassObject->thread1outPath, getCompressResult,minIndex,myClassObject->firstThread,myClassObject); return 0; }

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• Creation of model in core data on the fly

  - by user1740045

  How can we create a model in core data on the fly? I.e getting the schema of database from somewhere and then creating a Core Data Object graph? *QuesTion:* Yes thats fine, agreed with all the advantages. But, can anybody can tell practically, what is the benefit of integrating Core Data into project instead of using SQL directly. 1.No need to write SQL boiler plate code [but need to learn Core Data Model (steep curve)] 2.WE can undo and redo changes [but practically who needs it] 3.we can migrate to another schema [that can be done by SQLite as well jus need to add another field into table] 4.For say aggregation on some field in table,in Core Data we need to loop through Core Data Objects whereas in SQLite we need to first write SQLite Boiler Plate Code and then the basic aggregation SQL query,which is easy to write,only length of code will increase...But in case of Core Data (need to learn a lot). So apart from reducing the length of Code,does it actually adds value to project? or in terms of Memory Efficiency,Performance,etc.. PS: If anybody has actualy worked on Core Data(Model Creation On the Fly) , if possible share and gve pointers..thanks!

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• Optimising ruby regexp -- lots of match groups

  - by Farcaller

  I'm working on a ruby baser lexer. To improve performance, I joined up all tokens' regexps into one big regexp with match group names. The resulting regexp looks like: /\A(?<__anonymous_-1038694222803470993>(?-mix:\n+))|\A(?<__anonymous_-1394418499721420065>(?-mix:\/\/[\A\n]*))|\A(?<__anonymous_3077187815313752157>(?-mix:include\s+"[\A"]+"))|\A(?<LET>(?-mix:let\s))|\A(?<IN>(?-mix:in\s))|\A(?<CLASS>(?-mix:class\s))|\A(?<DEF>(?-mix:def\s))|\A(?<DEFM>(?-mix:defm\s))|\A(?<MULTICLASS>(?-mix:multiclass\s))|\A(?<FUNCNAME>(?-mix:![a-zA-Z_][a-zA-Z0-9_]*))|\A(?<ID>(?-mix:[a-zA-Z_][a-zA-Z0-9_]*))|\A(?<STRING>(?-mix:"[\A"]*"))|\A(?<NUMBER>(?-mix:[0-9]+))/ I'm matching it to my string producing a MatchData where exactly one token is parsed: bigregex =~ "\n ... garbage" puts $~.inspect Which outputs #<MatchData "\n" __anonymous_-1038694222803470993:"\n" __anonymous_-1394418499721420065:nil __anonymous_3077187815313752157:nil LET:nil IN:nil CLASS:nil DEF:nil DEFM:nil MULTICLASS:nil FUNCNAME:nil ID:nil STRING:nil NUMBER:nil> So, the regex actually matched the "\n" part. Now, I need to figure the match group where it belongs (it's clearly visible from #inspect output that it's _anonymous-1038694222803470993, but I need to get it programmatically). I could not find any option other than iterating over #names: m.names.each do |n| if m[n] type = n.to_sym resolved_type = (n.start_with?('__anonymous_') ? nil : type) val = m[n] break end end which verifies that the match group did have a match. The problem here is that it's slow (I spend about 10% of time in the loop; also 8% grabbing the @input[@pos..-1] to make sure that \A works as expected to match start of string (I do not discard input, just shift the @pos in it). You can check the full code at GH repo. Any ideas on how to make it at least a bit faster? Is there any option to figure the "successful" match group easier?

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• Thread-Safe lazy instantiating using MEF

  - by Xaqron

  // Member Variable private static readonly object _syncLock = new object(); // Now inside a static method foreach (var lazyObject in plugins) { if ((string)lazyObject.Metadata["key"] = "something") { lock (_syncLock) { // It seems the `IsValueCreated` is not up-to-date if (!lazyObject.IsValueCreated) lazyObject.value.DoSomething(); } return lazyObject.value; } } Here I need synchronized access per loop. There are many threads iterating this loop and based on the key they are looking for, a lazy instance is created and returned. lazyObject should not be created more that one time. Although Lazy class is for doing so and despite of the used lock, under high threading I have more than one instance created (I track this with a Interlocked.Increment on a volatile static int and log it somewhere). The problem is I don't have access to definition of Lazy and MEF defines how the Lazy class create objects. I should notice the CompositionContainer has a thread-safe option in constructor which is already used. My questions: 1) Why the lock doesn't work ? 2) Should I use an array of locks instead of one lock for performance improvement ?

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