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• Self-referencing tables in Linq2Sql

  - by J-Man

  Hi, I've seen a lot of questions on self-referencing tables in Linq2Sql and how to eagerly load all child records for a particular root object. I've implemented a temporary solution by accessing all underlying properties, but you can see that this doesn't do the performance any good. The thing is though, that all records are correlated with each-other using a correlation GUID. Example below: RootElement - Id: 1 - ParentId: null - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 2 - ParentId: 1 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement2 - Id: 3 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD ChildElement1 - Id: 4 - ParentId: 2 - CorrelationId: 4D68E512-4B55-44f4-BA5A-174B630A03DD In my case, I do have access to the correlationId, so I can retrieve all of my records by performing the following query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' select element; But, of course, I want these elements associated with each other by executing this query: from element in db.Elements where element.CorrelationId == '4D68E512-4B55-44f4-BA5A-174B630A03DD' && element.ParentId == null select element; My question is: is it possible to combine the results the first query as some sort of 'caching mechanism' for the query where I get the root element? Thanks for the input. J.

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• A queue in C using structs and dynamic memory allocation (linked list)

  - by Martin Pugh

  I am tasked with making a queue data structure in C, as a linked list. Our lecturer gave us a large amount of code to implement a stack, but we have to adapt it to create a queue. The code our lecturer gave us ends up not compiling and segfaulting at the exact same point as the code I wrote for the queue. I'm very new to structs, malloc and C in general, so there could be something painfully obvious I've overlooked. Here is the code I am using: #include <stdio.h> #include <stdlib.h> struct node{ int data; //contains the actual data struct node *prev; //pointer to previous node (Closer to front) struct node *next; //pointer to next node (Closer to back) }; typedef struct node *Nodepointer; struct queue{ Nodepointer front; Nodepointer back; }; typedef struct queue *Queuepointer; main(){ Queuepointer myqueue; //create a queue called myqueue init(myqueue); //initialise the queue Nodepointer new = (Nodepointer)malloc(sizeof(struct node)); myqueue->front = new; } int init(Queuepointer q){ q = (Queuepointer)malloc(sizeof(struct queue)); q->front = NULL; q->back = NULL; } The idea is that the queue struct 'contains' the first and last nodes in a queue, and when a node is created, myqueue is updated. However, I cannot even get to that part (pop and push are written but omitted for brevity). The code is segfaulting at the line myqueue->front = new; with the following gdb output: Program received signal SIGSEGV, Segmentation fault. 0x08048401 in main () at queue.c:27 27 myqueue->front = new; Any idea what I'm doing wrong?

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• How I shoud use BIT in MS SQL 2005

  - by adopilot

  Regarding to SQL performance. I have Scalar-Valued function for checking some specific condition in base, It returns BIT value True or False, I now do not know how I should fill @BIT parameter If I write. set @bit = convert(bit,1) or set @bit = 1 or set @bit='true' Function will work anyway but I do not know which method is recommended for daily use. Another Question, I have table in my base with around 4 million records, Daily insert is about 4K records in that table. Now I want to add CONSTRAINT on that table whit scalar valued function that I mentioned already Something like this ALTER TABLE fin_stavke ADD CONSTRAINT fin_stavke_knjizenje CHECK ( dbo.fn_ado_chk_fin(id)=convert(bit,1)) Where is filed "id" primary key of table fin_stavke and dbo.fn_ado_chk_fin looks like create FUNCTION fn_ado_chk_fin ( @stavka_id int ) RETURNS bit AS BEGIN declare @bit bit if exists (select * from fin_stavke where id=@stavka_id and doc_id is null and protocol_id is null) begin set @bit=0 end else begin set @bit=1 end return @bit; END GO Will this type and method of cheeking constraint will affect badly performance on my table and SQL at all ? If there is also better way to add control on this table please let me know.

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• Hibernate triggering constraint violations using orphanRemoval

  - by ptomli

  I'm having trouble with a JPA/Hibernate (3.5.3) setup, where I have an entity, an "Account" class, which has a list of child entities, "Contact" instances. I'm trying to be able to add/remove instances of Contact into a List<Contact> property of Account. Adding a new instance into the set and calling saveOrUpdate(account) persists everything lovely. If I then choose to remove the contact from the list and again call saveOrUpdate, the SQL Hibernate seems to produce involves setting the account_id column to null, which violates a database constraint. What am I doing wrong? The code below is clearly a simplified abstract but I think it covers the problem as I'm seeing the same results in different code, which really is about this simple. SQL: CREATE TABLE account ( INT account_id ); CREATE TABLE contact ( INT contact_id, INT account_id REFERENCES account (account_id) ); Java: @Entity class Account { @Id @Column public Long id; @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true) @JoinColumn(name = "account_id") public List<Contact> contacts; } @Entity class Contact { @Id @Column public Long id; @ManyToOne(optional = false) @JoinColumn(name = "account_id", nullable = false) public Account account; } Account account = new Account(); Contact contact = new Contact(); account.contacts.add(contact); saveOrUpdate(account); // some time later, like another servlet request.... account.contacts.remove(contact); saveOrUpdate(account); Result: UPDATE contact SET account_id = null WHERE contact_id = ? Edit #1: It might be that this is actually a bug http://opensource.atlassian.com/projects/hibernate/browse/HHH-5091

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• jQuery, unable to store data returned by $.get function.

  - by Deepak Prasanna

  I am trying to turn div#sidebar into a sidebar in my app. My code looks like the one below. $('#sidebar').userProfile(); jQuery.fn.userProfile = function() { $.get('/users/profile', function(data){ $(this).html(data); }); }; It didnt work because, I found the this (inside the $.get function) here contexts to the get request and not $('#sidebar'). Then I tried something like below. $('#sidebar').userProfile(); #This doesnot work jQuery.fn.userProfile = function() { var side_bar = null; $.get('/users/profile', function(data){ side_bar = data; }); $(this).html(side_bar); console.log(side_bar); }; This doesnt work either. In firebug console I see Null which I am setting on top when I am declaring the variable.Atlast I made it work by changing my code to something like below by hardcoding the selector. #This works, but I cannot turn any element to a sidebar which is sick. jQuery.fn.userProfile = function() { $.get('/users/profile', function(data){ $('#sidebar').html(data); }); }; But this is not I wanted because I wanted to turn any element to a sidebar. Where am I goin wrong or which is the correct way of doing it?

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• How to make this into a self contained jQuery plugin? Works inline.

  - by Jannis

  Hi, I have been trying to make this to be a little jQuery plugin that I can reuse in the future without having to write the following into my actions.js file in full. This works when loaded in the same file where I set the height using my variable tallest. var tallest = null; $('.slideshow img').each(function(index) { if ($(this).height() >= tallest ) { tallest = $(this).height(); } }); $('.slideshow').height(tallest); This works and will cycle through all the items, then set the value of tallest to the greatest height found. The following however does not work: This would be the plugin, loaded from its own file (before the actions.js file that contains the parts using this): (function($){ $.fn.extend({ tallest: function() { var tallest = null; return this.each(function() { if ($(this).height() >= tallest ) { tallest = $(this).height(); } }); } }); })(jQuery); Once loaded I am trying to use it as follows: $('.slideshow img').tallest(); $('.slideshow').height(tallest); However the above 2 lines return an error of 'tallest is undefined'. How can I make this work? Any ideas would be appreciated. Thinking about this even more the perfect usage of this would be as follows: $('.container').height(tallest('.container item')); But I wouldn't even know where to begin to get this to work in the manner that you pass the object to be measured into the function by adding it into the brackets of the function name.. Thanks for reading, Jannis

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• How to animate the drawing of a CGPath?

  - by Jordan Kay

  I am wondering if there is a way to do this using Core Animation. Specifically, I am adding a sub-layer to a layer-backed custom NSView and setting its delegate to another custom NSView. That class's drawInRect method draws a single CGPath: - (void)drawInRect:(CGRect)rect inContext:(CGContextRef)context { CGContextSaveGState(context); CGContextSetLineWidth(context, 12); CGMutablePathRef path = CGPathCreateMutable(); CGPathMoveToPoint(path, NULL, 0, 0); CGPathAddLineToPoint(path, NULL, rect.size.width, rect.size.height); CGContextBeginPath(context); CGContextAddPath(context, path); CGContextStrokePath(context); CGContextRestoreGState(context); } My desired effect would be to animate the drawing of this line. That is, I'd like for the line to actually "stretch" in an animated way. It seems like there would be a simple way to do this using Core Animation, but I haven't been able to come across any. Do you have any suggestions as to how I could accomplish this goal?

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• Is this correct for disposing an object using IDisposable

  - by robUK

  I have a class that implements the IDisposable interface. I am using a webclient to download some data using the AsyncDownloadString. I am wondering have I correctly declared my event handlers in the constructor and within the using statement of the web client? And is this correct way to remove the event handlers in the Dispose method? Overrule is this the correct way to use the IDisposable interface? public class Balance : IDisposable { //Constructor WebClient wc; public Balance() { using (wc = new WebClient()) { //Create event handler for the progress changed and download completed events wc.DownloadProgressChanged += new DownloadProgressChangedEventHandler(wc_DownloadProgressChanged); wc.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted); } } ~Balance() { this.Dispose(false); } //Get the current balance for the user that is logged in. //If the balance returned from the server is NULL display error to the user. //Null could occur if the DB has been stopped or the server is down. public void GetBalance(string sipUsername) { //Remove the underscore ( _ ) from the username, as this is not needed to get the balance. sipUsername = sipUsername.Remove(0, 1); string strURL = string.Format("https://www.xxxxxxx.com", sipUsername); //Download only when the webclient is not busy. if (!wc.IsBusy) { // Download the current balance. wc.DownloadStringAsync(new Uri(strURL)); } else { Console.Write("Busy please try again"); } } //return and display the balance after the download has fully completed void wc_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) { //Pass the result to the event handler } //Dispose of the balance object public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } //Remove the event handlers private bool isDisposed = false; private void Dispose(bool disposing) { if (!this.isDisposed) { if (disposing) { wc.DownloadProgressChanged -= new DownloadProgressChangedEventHandler(wc_DownloadProgressChanged); wc.DownloadStringCompleted -= new DownloadStringCompletedEventHandler(wc_DownloadStringCompleted); wc.Dispose(); } isDisposed = true; } } }

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• EVP_PKEY from char buffer in x509 (PKCS7)

  - by sid

  Hi All, I have a DER certificate from which I am retrieving the Public key in unsigned char buffer as following, is it the right way of getting? pStoredPublicKey = X509_get_pubkey(x509); if(pStoredPublicKey == NULL) { printf(": publicKey is NULL\n"); } if(pStoredPublicKey->type == EVP_PKEY_RSA) { RSA *x = pStoredPublicKey->pkey.rsa; bn = x->n; } else if(pStoredPublicKey->type == EVP_PKEY_DSA) { } else if(pStoredPublicKey->type == EVP_PKEY_EC) { } else { printf(" : Unkown publicKey\n"); } //extracts the bytes from public key & convert into unsigned char buffer buf_len = (size_t) BN_num_bytes (bn); key = (unsigned char *)malloc (buf_len); n = BN_bn2bin (bn, (unsigned char *) key); for (i = 0; i < n; i++) { printf("%02x\n", (unsigned char) key[i]); } keyLen = EVP_PKEY_size(pStoredPublicKey); EVP_PKEY_free(pStoredPublicKey); And, With this unsigned char buffer, How do I get back the EVP_PKEY for RSA? OR Can I use following ???, EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, unsigned char **pp, long length); int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);

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• PlaySound linker error in C++

  - by logic-unit

  Hello, I'm getting this error: [Linker error] undefined reference to 'PlaySoundA@12' Id returned 1 exit status From this code: // c++ program to generate a random sequence of numbers then play corresponding audio files #include <windows.h> #include <mmsystem.h> #include <iostream> #pragma comment(lib, "winmm.lib") using namespace std; int main() { int i; i = 0; // set the value of i while (i <= 11) // set the loop to run 11 times { int number; number = rand() % 10 + 1; // generate a random number sequence // cycling through the numbers to find the right wav and play it if (number == 0) { PlaySound("0.wav", NULL, SND_FILENAME); // play the random number } else if (number == 1) { PlaySound("1.wav", NULL, SND_FILENAME); // play the random number } //else ifs repeat to 11... i++; // increment i } return 0; } I've tried absolute and relative paths for the wavs, the file size of them is under 1Mb each too. I've read another thread here on the subject: http://stackoverflow.com/questions/1565439/how-to-playsound-in-c As you may well have guessed this is my first C++ program, so my knowledge is limited with where to go next. I've tried pretty much every page Google has on the subject including MSDN usage page. Any ideas? Thanks in advance...

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• Visual Studio Designer looses / ignores data

  - by Kempeth

  I'm writing my own control - a datagridviewcolumn that displays integer values as texts like the comboboxcolumn can but without showing the combobox unless the cell is edited. I'm mostly there but I have problems with the databinding. I managed to get the necessary properties to appear in the designer but every time I set the datasource and close the editor the changes are dropped. When I assign the same datasource later in code it works like a charm, I just would prefer not having to do that... public class DataGridViewLookupColumn : DataGridViewColumn { private DataGridViewLookupCell template; private Object datasource = null; private String displaymember = String.Empty; private String valuemember = String.Empty; private BindingSource bindingsource = new BindingSource(); public DataGridViewLookupColumn() : base() { this.template = new DataGridViewLookupCell(); } public override DataGridViewCell CellTemplate { get { return this.template; } set { } } [Category("Data")] [ DefaultValue(null), RefreshProperties(RefreshProperties.Repaint), AttributeProvider(typeof(IListSource)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public object DataSource { get { return this.bindingsource.DataSource; //return this.datasource; } set { this.bindingsource.DataSource = value; this.bindingsource.EndEdit(); } } [Category("Data")] [ DefaultValue(""), TypeConverterAttribute("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design"), Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design", typeof(System.Drawing.Design.UITypeEditor)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public String DisplayMember { get { return this.displaymember; } set { this.displaymember = value; } } [Category("Data")] [ DefaultValue(""), TypeConverterAttribute("System.Windows.Forms.Design.DataMemberFieldConverter, System.Design"), Editor("System.Windows.Forms.Design.DataMemberFieldEditor, System.Design", typeof(System.Drawing.Design.UITypeEditor)), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), ] public String ValueMember { get { return this.valuemember; } set { this.valuemember = value; } } } EDIT: I experimenting I just found out that that original DataGridViewComboBoxColumn can be made to behave exactly like I wanted to. By setting the DisplayStyle to Nothing the combobox control is only shown in edit mode.

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• How to loop video using NetStream in Data Generation Mode

  - by WesleyJohnson

  I'm using a NetStream in Data Generation Mode to play an embeded FLV using appendBytes. When the stream is finished playing, I'd like to loop the FLV file. I'm not sure how to achieve this. Here is what I have so far (this isn't a complete example): public function createBorderAnimation():void { // Load the skin image borderAnimation = Assets.BorderAnimation; // Convert the animation to a byte array borderAnimationBytes = new borderAnimation(); // Initialize the net connection border_nc = new NetConnection(); border_nc.connect( null ); // Initialize the net stream border_ns = new NetStream( border_nc ); border_ns.client = { onMetaData:function( obj:Object ):void{ trace(obj); } } border_ns.addEventListener( NetStatusEvent.NET_STATUS, border_netStatusHandler ); border_ns.play( null ); border_ns.appendBytes( borderAnimationBytes ); // Initialize the animation border_vd = new Video( 1024, 768 ); border_vd.attachNetStream( border_ns ); // Add the animation to the stage ui = new UIComponent(); ui.addChild( DisplayObject( border_vd ) ); grpBackground.addElement( ui ); } protected function border_netStatusHandler( event:NetStatusEvent ):void { if( event.info.code == "NetStream.Buffer.Flush" || event.info.code == "NetStream.Buffer.Empty" ) { border_ns.appendBytesAction( NetStreamAppendBytesAction.RESET_BEGIN ); border_ns.appendBytes( borderAnimationBytes ); border_ns.appendBytesAction( NetStreamAppendBytesAction.END_SEQUENCE ); } } This will loop the animation, but it starts chewing up memory like crazy. I've tried using NetStream.seek(0) and NetStream.appendBytesAction( NetStreamAppendBytesAction.RESET_SEEK ), but then I'm not sure what to do next. If you just try to call appendBytes again after that, it doesn't work, presumably because I'm appending the full byte array which has the FLV header and stuff? I'm not very familiar with how that all works. Any help is greatly appreciated.

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• Load binary file using fstream

  - by Kirill V. Lyadvinsky

  I'm trying to load binary file using fstream in the following way: #include <iostream #include <fstream #include <iterator #include <vector using namespace std; int main() { basic_fstream<uint32_t file( "somefile.dat", ios::in|ios::binary ); vector<uint32_t buffer; buffer.assign( istream_iterator<uint32_t, uint32_t( file ), istream_iterator<uint32_t, uint32_t() ); cout << buffer.size() << endl; return 0; } But it doesn't work. In Ubuntu it crashed with std::bad_cast exception. In MSVC++ 2008 it just prints 0. I know that I could use file.read to load file, but I want to use iterator and operator>> to load parts of the file. Is that possible? Why the code above doesn't work?

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• Struggling with a data modeling problem

  - by rpat

  I am struggling with a data model (I use MySQL for the database). I am uneasy about what I have come up with. If someone could suggest a better approach, or point me to some reference matter I would appreciate it. The data would have organizations of many types. I am trying to do a 3 level classification (Class, Category, Type). Say if I have 'Italian Restaurant', it will have the following classification Food Services Restaurants Italian However, an organization may belong to multiple groups. A restaurant may also serve Chinese and Italian. So it will fit into 2 classifications Food Services Restaurants Italian Food Services Restaurants Chinese The classification reference tables would be like the following: ORG_CLASS (RowId, ClassCode, ClassName) 1, FOOD, Food Services ORG_CATEGORY(RowId, ClassCode, CategoryCode, CategoryName) 1, FOOD, REST, Restaurants ORG_TYPE (RowId, ClassCode, CategoryCode, TypeCode, TypeName) 100, FOOD, REST, ITAL, Italian 101, FOOD, REST, CHIN, Chinese 102, FOOD, REST, SPAN, Spanish 103, FOOD, REST, MEXI, Mexican 104, FOOD, REST, FREN, French 105, FOOD, REST, MIDL, Middle Eastern The actual data tables would be like the following: I will allow an organization a max of 3 classifications. I will have 3 GroupIds each pointing to a row in ORG_TYPE. So I have my ORGANIZATION_TABLE ORGANIZATION_TABLE (OrgGroupId1, OrgGroupId2, OrgGroupId3, OrgName, OrgAddres) 100,103,NULL,MyRestaurant1, MyAddr1 100,102,NULL,MyRestaurant2, MyAddr2 100,104,105, MyRestaurant3, MyAddr3 During data add, a dialog could let the user choose the clssa, category, type and the corresponding GroupId could be populated with the rowid from the ORG_TYPE table. During Search, If all three classification are chosen, It will be more specific. For example, if Food Services Restaurants Italian is the criteria, the where clause would be 'where OrgGroupId1 = 100' If only 2 levels are chosen Food Services Restaurants I have to do 'where OrgGroupId1 in (100,101,102,103,104,105, .....)' - There could be a hundred in that list I will disallow class level search. That is I will force selection of a class and category The Ids would be integers. I am trying to see performance issues and other issues. Overall, would this work? or I need to throw this out and start from scratch.

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• T4MVC not generating an action

  - by Maslow

  I suspected there was some hidden magic somewhere that stopped what looks like actual method calls all over the place in T4MVC. Then I had a view fail to compile, and the stackTrace went into my actual method. [Authorize] public string Apply(string shortName) { if (shortName.IsNullOrEmpty()) return "Failed alliance name was not transmitted"; if (Request.IsAuthenticated == false || User == null || User.Identity == null) return "Apply authentication failed"; Models.Persistence.AlliancePersistance.Apply(User.Identity.Name, shortName); return "Applied"; } So this method isn't generating in the template after all. <%=Ajax.ActionLink("Apply", "Apply", new RouteValueDictionary() { { "shortName", item.Shortname } }, new AjaxOptions() { UpdateTargetId = "masterstatus" })%> <%=Html.ActionLink("Apply",MVC.Alliance.Apply(item.Shortname),new AjaxOptions() { UpdateTargetId = "masterstatus" }) %> The second method threw an exception on compile because the method Apply in my controller has an [Authorize] attribute so that if someone that isn't logged on clicks this, they get redirected to login, then right back to this page. There they can click on apply again, this time being logged in. And yes I realize one is Ajax.ActionLink while the other is Html.ActionLink I did try them both with the T4MVC version.

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• varchar comparison in SQL Server

  - by Ram

  I am looking for some SQL varchar comparison function like C# string.compare (we can ignore case for now, should return zero when the character expression are same and a non zero expression when they are different) Basically I have some alphanumeric column in one table which needs to be verified in another table. I cannot do select A.col1 - B.col1 from (query) as "-" operator cannot be applied on character expressions I cannot cast my expression as int (and then do a difference/subtraction) as it fails select cast ('ASXT000R' as int) Conversion failed when converting varchar 'ASXT000R' to int Soundex would not do it as soundex is same for 2 similar strings Difference would not do it as select difference('abc','ABC') = 4 (as per msdn, difference is the difference in the soundex of 2 character expressions and difference =4 implies least different) Is there any other way of doing it ?

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• Encoding h.264 with libavcodec/x264

  - by Leviathan

  I am attempting to encode video using libavcodec/libavformat. I'm trying to change the standard output-example.c from ffmpeg source. The AVI file is created on the disk, but the only sound is encoded. I tried adding a lot of options for x264 from here. All the other codecs works fine, mpeg2, mpeg4, mjpeg, xvid. In addition to specifying the parameters x264, I also set the codec to AVOutputFormat structure. That's all I've done. AVOutputFormat *pOutFormat; // in header file av_register_all(); AVCodec *codec = avcodec_find_encoder_by_name("libx264"); pOutFormat = guess_format("avi", NULL, NULL); pOutFormat->video_codec = codec->id; The debug output of my application: Output #0, mp4, to 'D:\1.avi': Stream #0.0: Video: libx264, yuv420p, 320x240, q=10-51, 500 kb/s, 90k tbn, 25 tbc Stream #0.1: Audio: aac, 44100 Hz, 1 channels, s16, 128 kb/s [libx264 @ 0x694010]using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.2 [libx264 @ 0x694010]bitrate tolerance too small, using .01 [libx264 @ 0x694010]profile Main, level 2.0 [libx264 @ 0x694010]frame I:150 Avg QP:14.76 size: 2534 [libx264 @ 0x694010]mb I I16..4: 75.9% 0.0% 24.1% [libx264 @ 0x694010]final ratefactor: 17.57 [libx264 @ 0x694010]coded y,uvDC,uvAC intra: 42.7% 92.4% 47.4% [libx264 @ 0x694010]i16 v,h,dc,p: 11% 14% 2% 73% [libx264 @ 0x694010]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 21% 18% 29% 5% 8% 10% 3% 3% 2% [libx264 @ 0x694010]kb/s:506.79

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• Practical differences between classes and structs in .net (not conceptual)?

  - by Gulshan

  Whenever I tried to search about differences between classes and structs in C# or .net, I ended up with the conceptual overview of the two things like value type or the reference type, where the variables are allocated etc. But I need some practical differences. I have found some like different behavior of assignment operator, having constructors etc. Can anybody provide some more practical differences which will be directly useful while coding? Like the things works with one but not with other or same operation showing different behavior. And some common mistakes regarding these two. Also please suggest where to consider using a struct instead of a class. And where the structs should not be used.

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• How does this C# asp.net random password code work?

  - by quakkels

  Hello all, I'm new to .NET and C# and I'm trying to figure out how this code works: public static string CreateRandomPassword(int PasswordLength) { String _allowedChars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ23456789"; Byte[] randomBytes = new Byte[PasswordLength]; RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider(); rng.GetBytes(randomBytes); char[] chars = new char[PasswordLength]; int allowedCharCount = _allowedChars.Length; for(int i = 0;i<PasswordLength;i++) { /// /// I don't understand how this line works: /// chars[i] = _allowedChars[(int)randomBytes[i] % allowedCharCount]; } return new string(chars); } I think I've got a pretty good handle on most of this. I haven't been able to understand the following line: chars[i] = _allowedChars[(int)randomBytes[i] % allowedCharCount]; I understand that the code generates random binary numbers and uses those random numbers in the for loop to select a character from the _allowedChars string. What I don't get is why this code uses the modulous operator (%) to get the _allowedChars index value. Thanks for any help

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• how to convert bitmap into byte array in android

  - by satyamurthy

  hi all i am new in android i am implementing image retrieve in sdcard in image convert into bitmap and in bitmap convert in to byte array please forward some solution of this code public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); ImageView image = (ImageView) findViewById(R.id.picview); EditText value=(EditText)findViewById(R.id.EditText01); FileInputStream in; BufferedInputStream buf; try { in = new FileInputStream("/sdcard/pictures/1.jpg"); buf = new BufferedInputStream(in,1070); System.out.println("1.................."+buf); byte[] bMapArray= new byte[buf.available()]; buf.read(bMapArray); Bitmap bMap = BitmapFactory.decodeByteArray(bMapArray, 0, bMapArray.length); for (int i = 0; i < bMapArray.length; i++) { System.out.print("bytearray"+bMapArray[i]); } image.setImageBitmap(bMap); value.setText(bMapArray.toString()); if (in != null) { in.close(); } if (buf != null) { buf.close(); } } catch (Exception e) { Log.e("Error reading file", e.toString()); } } } solution is 04-12 16:41:16.168: INFO/System.out(728): 4......................[B@435a2908 this is the result for byte array not display total byte array this array size is 1034 please forward some solution

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• GCC - How to realign stack?

  - by psihodelia

  I try to build an application which uses pthreads and __m128 SSE type. According to GCC manual, default stack alignment is 16 bytes. In order to use __m128, the requirement is the 16-byte alignment. My target CPU supports SSE. I use a GCC compiler which doesn't support runtime stack realignment (e.g. -mstackrealign). I cannot use any other GCC compiler version. My test application looks like: #include <xmmintrin.h> #include <pthread.h> void *f(void *x){ __m128 y; ... } int main(void){ pthread_t p; pthread_create(&p, NULL, f, NULL); } The application generates an exception and exits. After a simple debugging (printf "%p", &y), I found that the variable y is not 16-byte aligned. My question is: how can I realign the stack properly (16-byte) without using any GCC flags and attributes (they don't help)? Should I use GCC inline Assembler within this thread function f()?

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• MyMessage<T> throws an exception when calling XmlSerializer

  - by Arthis

  I am very new to nservicebus. I am using version 3.0.1, the last one up to date. And I wonder if my case is a normal limitation of NSB, I am not aware of. I have an asp.net MVC application, I am trying to setup and in my global.asax, I have the following : var configure = Configure.WithWeb() .DefaultBuilder() .ForMvc() .XmlSerializer(); But I have an error with the XmlSerializer when dealing with one of my object: [Serializable] public class MyMessage<T> : IMessage { public T myobject { get; set; } } I pass trough : XmlSerializer() instance.Initialize(types); this.InitType(type, moduleBuilder); this.InitType(info2.PropertyType, moduleBuilder); and then when dealing With T, string typeName = GetTypeName(t); typename is null and the following instruction : if (!nameToType.ContainsKey(typeName)) ends in error. null value not allowed. Is this some limitations to Nservicebus, or am I messing something up?

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• How do i cast A to object to class A when B can typcast to A?

  - by acidzombie24

  Basically i want to do this. ee causes a bad cast exception. NOTE: o can be ANYTHING. It may not be B, it can be C, D, E, F etc. But this should work as long as o is a class that can typecast into A (B is such a class. It uses an implicit operator overload) var b = (B)"sz"; var e = (A)b; object o = b; var ee = (A)o;

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• How do I fork a maximum of 5 child processes of the parent at any one time?

  - by bstullkid

  I have the following code, which I'm trying to only allow a maximum of 5 children to run at a time, but I can't figure out how to decrement the child count when a child exits. struct { char *s1; char *s2; } s[] = { {"one", "oneB"}, {"two", "twoB"}, {"three", "thr4eeB"}, {"asdf", "3th43reeB"}, {"asdfasdf", "thr33eeB"}, {"asdfasdfasdf", "thdfdreeB"}, {"af3c3", "thrasdfeeB"}, {"fec33", "threfdeB"}, {NULL, NULL} }; int main(int argc, char *argv[]) { int i, im5, children = 0; int pid = fork(); for (i = 0; s[i].s2; i++) { im5 = 0; switch (pid) { case -1: { printf("Error\n"); exit(255); } case 0: { printf("%s -> %s\n", s[i].s1, s[i].s2); if (i==5) im5 = 1; printf("%d\n", im5); sleep(i); exit(1); } default: { // Here is where I need to sleep the parent until chilren < 5 // so where do i decrement children so that it gets modified in the parent process? while(children > 5) sleep(1); children++; pid = fork(); } } } return 1; }

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• Persist changes in C

  - by Mohit Deshpande

  I am developing a database-like application that stores a a structure containing: struct Dictionary { char *key; char *value; struct Dictionary *next; }; As you can see, I am using a linked list to store information. But the problem begins when the user exits out of the program. I want the information to be stored somewhere. So I was thinking of storing the linked list in a permanent or temporary file using fopen, then, when the user starts the program, retrieve the linked list. Here is the method that prints the linked list to the console: void PrintList() { int count = 0; struct Dictionary *current; current = head; if (current == NULL) { printf("\nThe list is empty!"); return; } printf(" Key \t Value\n"); printf(" ======== \t ========\n"); while (current != NULL) { count++; printf("%d. %s \t %s\n", count, current->key, current->value); current = current->next; } } So I am thinking of modifying this method to print the information through fprintf instead of printf and then the program would just get the infomation from the file. Could someone help me on how I can read and write to this file? What kind of file should it be, temporary or regular? How should I format the file (like I was thinking of just having the key first, then the value, then a newline character)?

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