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Hyperlink in Silverlight AccordionItem HeaderTemplate

- by Charlie Brown

I have created a HeaderTemplate for my accordions where I want to display a text block on one side of the header and a hyperlink on the right side. The display is working correctly, but the click event is not called when the user clicks, I'm guessing b/c the header itself is trapping the click for expand/contract. <layoutToolkit:Accordion> <layoutToolkit:AccordionItem IsSelected="True"> <layoutToolkit:AccordionItem.HeaderTemplate> <DataTemplate> <StackPanel Orientation="Horizontal" Height="20"> <TextBlock Margin="0,0,700,0">Cancel Postcards</TextBlock> <HyperlinkButton Content="Next Call" Foreground="Blue" Click="NextCancel_Click" /> </StackPanel> </DataTemplate> </layoutToolkit:AccordionItem.HeaderTemplate> ..... more code .... Is there a way to get the hyperlink to respond to events without practically creating a new control?

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Integer array or struct array - which is better?

- by MusiGenesis

In my app, I'm storing Bitmap data in a two-dimensional integer array (int[,]). To access the R, G and B values I use something like this: // read: int i = _data[x, y]; byte B = (byte)(i >> 0); byte G = (byte)(i >> 8); byte R = (byte)(i >> 16); // write: _data[x, y] = BitConverter.ToInt32(new byte[] { B, G, R, 0 }, 0); I'm using integer arrays instead of an actual System.Drawing.Bitmap because my app runs on Windows Mobile devices where the memory available for creating bitmaps is severely limited. I'm wondering, though, if it would make more sense to declare a structure like this: public struct RGB { public byte R; public byte G; public byte B; } ... and then use an array of RGB instead of an array of int. This way I could easily read and write the separate R, G and B values without having to do bit-shifting and BitConverter-ing. I vaguely remember something from days of yore about byte variables being block-aligned on 32-bit systems, so that a byte actually takes up 4 bytes of memory instead of just 1 (but maybe this was just a Visual Basic thing). Would using an array of structs (like the RGB example` above) be faster than using an array of ints, and would it use 3/4 the memory or 3 times the memory of ints?

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javascript mouse cursor change on page load in firefox browser 3.5

- by Amit

Hi in case of full page submit a trasparent div id coming and changing the cursor to 'wait' . Now when the page is getting submitted and new page is coming up cursor still remains to 'wait' not changing to default until mouse is moved in Firefox Here is simple html click on show button div is coming when user move mouse over the div cursor is changing as wait cursor. Now when this page is loaded again pressing F5 cursor remain as wait cursor in firefox its working fine in IE is there any way to make the cursor as default on pageload in Firefox <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Untitled Document</title> <style> body{ cursor:default; } </style> <script src="js/jquery.js"> </script> <script> var test = true; $(document).ready(function(){ $('#maindiv').css('display','none') }); function showDiv(){ $('#maindiv').css('display','block') } </script> </head> <body> <div id="divBody" style="background-color:red;width:500px;height:500px" >aa <div id="maindiv" style="background-color:#999999;height:100$;width:400px;height:400px;cursor:wait"> sss </div>aa </div> <input type="button" value="show" onclick="showDiv()"/> </body> </html>

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Are programming languages and methods inefficient? (assembler and C knowledge needed)

- by b-gen-jack-o-neill

Hi, for a long time, I am thinking and studying output of C language compiler in assembler form, as well as CPU architecture. I know this may be silly to you, but it seems to me that something is very ineffective. Please, don´t be angry if I am wrong, and there is some reason I do not see for all these principles. I will be very glad if you tell me why is it designed this way. I actually truly believe I am wrong, I know the genius minds of people which get PCs together knew a reason to do so. What exactly, do you ask? I´ll tell you right away, I use C as a example: 1: Stack local scope memory allocation: So, typical local memory allocation uses stack. Just copy esp to ebp and than allocate all the memory via ebp. OK, I would understand this if you explicitly need allocate RAM by default stack values, but if I do understand it correctly, modern OS use paging as a translation layer between application and physical RAM, when address you desire is further translated before reaching actual RAM byte. So why don´t just say 0x00000000 is int a,0x00000004 is int b and so? And access them just by mov 0x00000000,#10? Because you wont actually access memory blocks 0x00000000 and 0x00000004 but those your OS set the paging tables to. Actually, since memory allocation by ebp and esp use indirect addressing, "my" way would be even faster. 2: Variable allocation duplicity: When you run application, Loader load its code into RAM. When you create variable, or string, compiler generates code that pushes these values on the top o stack when created in main. So there is actual instruction for do so, and that actual number in memory. So, there are 2 entries of the same value in RAM. One in form of instruction, second in form of actual bytes in the RAM. But why? Why not to just when declaring variable count at which memory block it would be, than when used, just insert this memory location?

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JQuery tablesorter - Second click on column header doesn't resort

- by Jonathan

I'm using tablesorter in on a table I added to a view in django's admin (although I'm not sure this is relevant). I'm extending the html's header: {% block extrahead %} <script type="text/javascript" src="http://code.jquery.com/jquery-1.4.2.js"></script> <script type="text/javascript" src="http://mysite.com/media/tablesorter/jquery.tablesorter.js"></script> <script type="text/javascript"> $(document).ready(function() { $("#myTable").tablesorter(); } ); </script> {% endblock %} When I click on a column header, it sorts the table using this column in descending order - that's ok. When I click the same column header a second time - it does not reorder to ascending order. What's wrong with it? the table's html looks like: <table id="myTable" border="1"> <thead> <tr> <th>column_name_1</th> <th>column_name_2</th> <th>column_name_3</th> </tr> </thead> <tbody> {% for item in extra.items %} <tr> <td>{{ item.0|safe }} </td> <td>{{ item.1|safe }} </td> <td>{{ item.2|safe }} </td> </tr> {% endfor %} </tbody> </table>

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Inline function and global variable issue in Javascript

- by Natim

I have some code here : http://bitbucket.org/natim/lo53_tp1/src/tip/part3/camions/medias/js/tracking.js That I use to draw some information about trucks direction. The problem come from a function defined in a for loop like this one : ... for(i = 0; i < nb_trucks; i++) { ... contentString = '<div id="content">'+ trucks[i]['name'] + '</div>'; current_window = new google.maps.InfoWindow({ content: contentString }); infosWindow.push(current_window); current_marker = new google.maps.Marker({ map: map, position: new google.maps.LatLng(trucks[i]['end']['lat'], trucks[i]['end']['lon']), draggable: false, title: trucks[i]['name'] }); markers.push(current_marker); google.maps.event.addListener(current_marker, 'click', function() { current_window.open(map, current_marker); }); } In this code, you can see the last block google.maps.event.addListener(current_marker, 'click', function() { current_window.open(map, current_marker); }); And my problem is that current_marker in the addListener parameters is different from the one inside the function. The current_window and the current_marker inside the function is overide at each loop turn. How can I get it right ? Thanks

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CSS- How to align background image over bottom border line? Jsfiddle included

- by John Robinson

I have an image I am trying to display over the top of a bottom border, but it is being arranged behind the bottom border element (in this example, named "divider"), and I can't get it to align correctly. I would like the image to be displayed in the middle of the the border element and over the top of it. Vertically, I am trying to get the 1px line on the left and right side of the image to align with the 1px border to appear as if it is one element. Here is the code: .divider { border-bottom: 1px solid #c3c3c3; clear: both; display: block; margin-bottom: 20px; padding-top: 20px; width: 100%; } .sidearrow { background: url(http://s16.postimage.org/sbf7v9n75/sidearrow.png) 50% 14px no-repeat; width: 100%; height: 25px; }? <p>Here is some content above</p> <div class="sidearrow"></div> <div class="divider"></div> <p>Here is some content below</p>? And the jsfiddle: http://jsfiddle.net/F5xjx/2/ Any ideas how to get this to work? Thanks in advance.

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Testing form submission with Cucumber

- by picardo

I wrote a simple Cuke feature for a form on a demo site. The feature looks like this. Given I am on the home page When I set the "Start Date" to "2010-10-25" And I set the "End Date" to "2011-1-3" And I press the "Go" button Then I should see "Cake Shop" The idea is that after I press the Go button, a new page will load, showing a list of results, and one of the results should be "Cake Shop." But I have not managed to get this to work. Is there something that I am missing? Edit: here is the step definitions. Given /^I am on the "([^"]*)" page$/ do |page| visit root_path end When /^I set the "([^"]*)" to "([^"]*)"$/ do |field, date| fill_in field, :with=>date end When /^I press the "([^"]*)" button$/ do |arg1| click_button('Go') end The final step is defined in web_steps.rb I believe....and it's always there that it's failing. Then I should see "Cake Shop" # features/step_definitions/web_steps.rb:107 expected #has_content?("Cake Shop") to return true, got false (RSpec::Expectations::ExpectationNotMetError) ./features/step_definitions/web_steps.rb:110:in block (2 levels) in <top (required)>' ./features/step_definitions/web_steps.rb:14:in with_scope' ./features/step_definitions/web_steps.rb:108:in /^(?:|I )should see "([^"]*)"(?: within "([^"]*)")?$/' features/specify_timerange.feature:12:in Then I should see "Cake Shop"'

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values not equal in sqlite and json array in android

- by Venkat

I am trying to compare the value in sqlite table and id of the webservice what i have done so far is if(data_exist!=bookProduct.length()){ Log.i("in update","m here"); Cursor cursors = getRawEvents("select id from bcuk_book"); try{ for (int i = 0; i < bookProduct.length(); i++) { JSONObject c = bookProduct.getJSONObject(i); String Bid = c.getString(TAG_ID); ArrayList<String> mapId = new ArrayList<String>(); while(cursors.moveToNext()) { Log.e("cursors",cursors.getString(0)); Log.i(Bid,Bid); if(cursors.getString(0)!=c.getString(TAG_ID)){ Log.e("fas",Bid); } } mapId.add(TAG_ID); Log.e(Bid,Bid); } } My issue is i am getting same values in logs.. if(cursors.getString(0)!=c.getString(TAG_ID)){ this condition says if they are not equal then print the log..But the issue is i am entering into that block even i am getting same values from sqlite and TAG_ID i.e from json webservice..How to solve this.Where i done wrong?

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php: autoload exception handling.

- by YuriKolovsky

Hello again, I'm extending my previous question (Handling exceptions within exception handle) to address my bad coding practice. I'm trying to delegate autoload errors to a exception handler. <?php function __autoload($class_name) { $file = $class_name.'.php'; try { if (file_exists($file)) { include $file; }else{ throw new loadException("File $file is missing"); } if(!class_exists($class_name,false)){ throw new loadException("Class $class_name missing in $file"); } }catch(loadException $e){ header("HTTP/1.0 500 Internal Server Error"); $e->loadErrorPage('500'); exit; } return true; } class loadException extends Exception { public function __toString() { return get_class($this) . " in {$this->file}({$this->line})".PHP_EOL ."'{$this->message}'".PHP_EOL . "{$this->getTraceAsString()}"; } public function loadErrorPage($code){ try { $page = new pageClass(); echo $page->showPage($code); }catch(Exception $e){ echo 'fatal error: ', $code; } } } $test = new testClass(); ?> the above script is supposed to load a 404 page if the testClass.php file is missing, and it works fine, UNLESS the pageClass.php file is missing as well, in which case I see a "Fatal error: Class 'pageClass' not found in D:\xampp\htdocs\Test\PHP\errorhandle\index.php on line 29" instead of the "fatal error: 500" message I do not want to add a try/catch block to each and every class autoload (object creation), so i tried this. What is the proper way of handling this?

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where does a novice begin with error logging in asp.net c# ?

- by korben

i'm a novice teaching myself asp.net in c# via trial and error learn by doing, unfortunately this means lots of errors! i have a custom errors page now that is basically a 404 so that site visitors don't get that ugly application error message .NET throws, but i WOULD like to be able to see what's going wrong myself as people use the site. so i'm looking to build or learn from a fairly basic error logging c# class, that will send the same information given in a browser when hitting a .NET error, send this into a TXT file and email me the error at the same time would be great i don't know where to even begin, can someone give me some pointers? an open source class that does this already that i could plugin and play with would work as well. otherwise some links or guidance on where to start reading would be great too. i sort of have a mental block on understand msdn info-dump pages though, i'm hoping to find some articles on real people talking about implementing the same thing themselves or something like that please note i'm not looking to use some extensive or complicated third party service for this, i'm hoping to learn from the process of implementing a concise customized one

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jquery equivalent for css3 transition ease-in

- by Sebsemillia

I want to make a jquery version of this css3 effect so that it also works in ff and ie: a:hover {color: #354250; -webkit-transition:background 500ms ease-in;} a.more:hover, a.more:focus, a.more:active {background-position: 0 -18px;} a.more:link, a.more:visited { background: url(images/moreButton.png) no-repeat 0 0; display: inline-block; height:18px; margin-top:10px; text-indent: -9999px; width:77px; } My tries didn't work, here is what I' ve got so far. $("a.more").hover(function() { $(this).stop().animate({ color: '#354250', backgroundPosition: '0px -18px' }, slow, function() { $(this).stop().animate({ color: '#ad5332', backgroundPosition: '0px 0px'}, 0); }); }, function() { $(this).stop().animate({ color: '#ad5332', backgroundPosition: '0px 0px' }, 0); }); Do you have any idea how to fix this? Thank you very much!

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What's the best way to only output a tag if it exists in XSL?

- by Morinar

I'm working on an interface with a 3rd party app that basically needs to take XML that was spat out by the app and convert it into XML our system can deal with. It's basically just applying a stylesheet to the original XML to make it looks like "our" XML. I've noticed that in other stylesheets we have, there are constructs like this: <xsl:for-each select="State"> <StateAbbreviation> <xsl:value-of select="."/> </StateAbbreviation> </xsl:for-each> Basically, the "in" XML has a State tag that I need to output as our recognized StateAbbreviation tag. However, I want to ONLY output the StateAbbreviation tag if the "in" XML contains the State tag. The block above accomplishes this just fine, but is not very intuitive (at least it wasn't to me), as every time I see a for-each I assume there is more than one, whereas in these cases there is 0 or 1. My question: is that a standard-ish construct? If not, is there a more preferred way to do it? I could obviously check the string length (which is also being done in other stylesheets), but would like to do it the same, "best" way everywhere (assuming of course that a "best" way exists. Advice? Suggestions?

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Pass scalar/list context to called subroutine

- by Will

I'm trying to write a sub that takes a coderef parameter. My sub does some initialization, calls the coderef, then does some cleanup. I need to call the coderef using the same context (scalar, list, void context) that my sub was called in. The only way I can think of is something like this: sub perform { my ($self, $code) = @_; # do some initialization... my @ret; my $ret; if (not defined wantarray) { $code->(); } elsif (wantarray) { @ret = $code->(); } else { $ret = $code->(); } # do some cleanup... if (not defined wantarray) { return; } elsif (wantarray) { return @ret; } else { return $ret; } } Obviously there's a good deal of redundancy in this code. Is there any way to reduce or eliminate any of this redundancy? EDIT I later realized that I need to run $code->() in an eval block so that the cleanup runs even if the code dies. Adding eval support, and combining the suggestions of user502515 and cjm, here's what I've come up with. sub perform { my ($self, $code) = @_; # do some initialization... my $w = wantarray; return sub { my $error = $@; # do some cleanup... die $error if $error; # propagate exception return $w ? @_ : $_[0]; }->(eval { $w ? $code->() : scalar($code->()) }); } This gets rid of the redundancy, though unfortunately now the control flow is a little harder to follow.

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Is memory allocation in linux non-blocking?

- by Mark

I am curious to know if the allocating memory using a default new operator is a non-blocking operation. e.g. struct Node { int a,b; }; ... Node foo = new Node(); If multiple threads tried to create a new Node and if one of them was suspended by the OS in the middle of allocation, would it block other threads from making progress? The reason why I ask is because I had a concurrent data structure that created new nodes. I then modified the algorithm to recycle the nodes. The throughput performance of the two algorithms was virtually identical on a 24 core machine. However, I then created an interference program that ran on all the system cores in order to create as much OS pre-emption as possible. The throughput performance of the algorithm that created new nodes decreased by a factor of 5 relative the the algorithm that recycled nodes. I'm curious to know why this would occur. Thanks. *Edit : pointing me to the code for the c++ memory allocator for linux would be helpful as well. I tried looking before posting this question, but had trouble finding it.

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PHP -- automatic SQL injection protection?

- by ashgromnies

I took over maintenance of a PHP app recently and I'm not super familiar with PHP but some of the things I've been seeing on the site are making me nervous that it could be vulnerable to a SQL injection attack. For example, see how this code for logging into the administrative section works: $password = md5(HASH_SALT . $_POST['loginPass']); $query = "SELECT * FROM `administrators` WHERE `active`='1' AND `email`='{$_POST['loginEmail']}' AND `password`='{$password}'"; $userInfo = db_fetch_array(db_query($query)); if($userInfo['id']) { $_SESSION['adminLoggedIn'] = true; // user is logged in, other junk happens here, not important The creators of the site made a special db_query method and db_fetch_array method, shown here: function db_query($qstring,$print=0) { return @mysql(DB_NAME,$qstring); } function db_fetch_array($qhandle) { return @mysql_fetch_array($qhandle); } Now, this makes me think I should be able to do some sort of SQL injection attack with an email address like: ' OR 'x'='x' LIMIT 1; and some random password. When I use that on the command line, I get an administrative user back, but when I try it in the application, I get an invalid username/password error, like I should. Could there be some sort of global PHP configuration they have enabled to block these attacks? Where would that be configured? Here is the PHP --version information: # php --version PHP 5.2.12 (cli) (built: Feb 28 2010 15:59:21) Copyright (c) 1997-2009 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2009 Zend Technologies with the ionCube PHP Loader v3.3.14, Copyright (c) 2002-2010, by ionCube Ltd., and with Zend Optimizer v3.3.9, Copyright (c) 1998-2009, by Zend Technologies

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multiple clients - one server connection with sockets tcp/ip c# .net

- by jagse

Hello guys, I need to develop a client server system where I can have multiple clients communicating with one server at the same time. I want to communicate xml serialized objects and also need to send and receive other commands to invoke methods. Now, I am just starting with socket programming in C# and .Net and found that the asynchronous I/O is the way to go so that the methods dont block the execution of code. Also there are many examples of how to make a simple client server system. So I have a basic understanding of how that works. Anyway, what still is not clear to me is how I can set up a server which can manage connections to multiple clients? Can I just create a new socket per connection and then store those in some kind of list? Do I need some kind of multiplexing to achieve this? Do I have to listen at multiple ports? What`s the best way here? And the other thing is if I need to develop my own protocol to differentiate between what I am actually sending over the network -- xml serialized object or a command which might be just a string encoded in ascII or something. Or would I develop my own protocol just to send these commands? Any kind of help is apreciated! If someone knows a good book which covers this sort of stuff, let me know. Cheers I forgot to mention that some of my clients which are supposed to communicate with my server will be pda and I therefore use the compact framework... So this might bring in some restrictions...

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Trie Backtracking in Recursion

- by Darksky

I am building a tree for a spell checker with suggestions. Each node contains a key (a letter) and a value (array of letters down that path). So assume the following sub-trie in my big trie: W / \ a e | | k k | | is word--> e e | ... This is just a subpath of a sub-trie. W is a node and a and e are two nodes in its value array etc... At each node, I check if the next letter in the word is a value of the node. I am trying to support mistyped vowels for now. So 'weke' will yield 'wake' as a suggestion. Here's my searchWord function in my trie: def searchWord(self, word, path=""): if len(word) > 0: key = word[0] word = word[1:] if self.values.has_key(key): path = path + key nextNode = self.values[key] return nextNode.searchWord(word, path) else: # check here if key is a vowel. If it is, check for other vowel substitutes else: if self.isWord: return path # this is the word found else: return None Given 'weke', at the end when word is of length zero and path is 'weke', my code will hit the second big else block. weke is not marked as a word and so it will return with None. This will return out of searchWord with None. To avoid this, at each stack unwind or recursion backtrack, I need to check if a letter is a vowel and if it is, do the checking again. I changed the if self.values.has_key(key) loop to the following: if self.values.has_key(key): path = path + key nextNode = self.values[key] ret = nextNode.searchWord(word, path) if ret == None: # check if key == vowel and replace path # return nextNode.searchWord(... return ret What am I doing wrong here? What can I do when backtracking to achieve what I'm trying to do?

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Sequential access to asynchronous sockets

- by Lars A. Brekken

I have a server that has several clients C1...Cn to each of which there is a TCP connection established. There are less than 10,000 clients. The message protocol is request/response based, where the server sends a request to a client and then the client sends a response. The server has several threads, T1...Tm, and each of these may send requests to any of the clients. I want to make sure that only one of these threads can send a request to a specific client at any one time, while the other threads wanting to send a request to the same client will have to wait. I do not want to block threads from sending requests to different clients at the same time. E.g. If T1 is sending a request to C3, another thread T2 should not be able to send anything to C3 until T1 has received its response. I was thinking of using a simple lock statement on the socket: lock (c3Socket) { // Send request to C3 // Get response from C3 } I am using asynchronous sockets, so I may have to use Monitor instead: Monitor.Enter(c3Socket); // Before calling .BeginReceive() And Monitor.Exit(c3Socket); // In .EndReceive I am worried about stuff going wrong and not letting go of the monitor and therefore blocking all access to a client. I'm thinking that my heartbeat thread could use Monitor.TryEnter() with a timeout and throw out sockets that it cannot get the monitor for. Would it make sense for me to make the Begin and End calls synchronous in order to be able to use the lock() statement? I know that I would be sacrificing concurrency for simplicity in this case, but it may be worth it. Am I overlooking anything here? Any input appreciated.

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Trouble determining onclick's target

- by pwseo

I've tried and tried... and I can't seem to make this work in IE (tested version 6) Can anybody help me? IE complains about an error but refuses to tell which error it is... var a = document.getElementsByTagName("a"); for (i = 0; i < a.length; i++) { if (a[i].getAttribute("class") == "info-link") { a[i].onclick = function(e) { e = e || window.event; var target = e.srcElement || e.target; var info = target.parentNode.getElementsByTagName("div")[0]; if (info.style.display == "none" || info.style.display == "") { info.style.display = "block"; } else { info.style.display = "none"; } return false; } } } <div class="auxdata"> <a href="#" class="info-link">Esta questão possuí dados anexos. Clique para ver.</a> <div style="display: none;" class="info-inner">  </div> </div>

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How to mock a String using mockito?

- by Alceu Costa

I need to simulate a test scenario in which I call the getBytes() method of a String object and I get an UnsupportedEncodingException. I have tried to achieve that using the following code: String nonEncodedString = mock(String.class); when(nonEncodedString.getBytes(anyString())).thenThrow(new UnsupportedEncodingException("Parsing error.")); The problem is that when I run my test case I get a MockitoException that says that I can't mock a java.lang.String class. Is there a way to mock a String object using mockito or, alternatively, a way to make my String object throw an UnsupportedEncodingException when I call the getBytes method? Here are more details to illustrate the problem: This is the class that I want to test: public final class A{ public static String f(String str){ try{ return new String(str.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { // This is the catch block that I want to exercise. ... } } } This is my testing class (I'm using JUnit 4 and mockito): public class TestA { @Test(expected=UnsupportedEncodingException.class) public void test(){ String aString = mock(String.class); when(nonEncodedString.getBytes(anyString())).thenThrow(new UnsupportedEncodingException("Parsing error.")); A.f(aString); } }

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ZeroMQ REQ/REP on ipc:// and concurrency

- by Metiu

I implemented a JSON-RPC server using a REQ/REP 0MQ ipc:// socket and I'm experiencing strange behavior which I suspect is due to the fact that the ipc:// underlying unix socket is not a real socket, but rather a single pipe. From the documentation, one has to enforce strict zmq_send()/zmq_recv() alternation, otherwise the out-of-order zmq_send() will return an error. However, I expected the enforcement to be per-client, not per-socket. Of course with a Unix socket there is just one pipeline from multiple clients to the server, so the server won't know who it is talking with. Two clients could zmq_send() simultaneously and the server would see this as an alternation violation. The sequence could be: ClientA: zmq_send() ClientB: zmq_send() : will it block until the other send/receive completes? will it return -1? (I suspect it will with ipc:// due to inherent low-level problems, but with TCP it could distinguish the two clients) ClientA: zmq_recv() ClientB: zmq_recv() so what about tcp:// sockets? Will it work concurrently? Should I use some other locking mechanism to work around this?

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Improving I/O performance in C++ programs[external merge sort]

- by Ajay

I am currently working on a project involving external merge-sort using replacement-selection and k-way merge. I have implemented the project in C++[runs on linux]. Its very simple and right now deals with only fixed sized records. For reading & writing I use (i/o)fstream classes. After executing the program for few iterations, I noticed that I/O read blocks for requests of size more than 4K(typical block size). Infact giving buffer sizes greater than 4K causes performance to decrease. The output operations does not seem to need buffering, linux seemed to take care of buffering output. So I issue a write(record) instead of maintaining special buffer of writes and then flushing them out at once using write(records[]). But the performance of the application does not seem to be great. How could I improve the performance? Should I maintain special I/O threads to take care of reading blocks or are there existing C++ classes providing this abstraction already?(Something like BufferedInputStream in java)

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Using the Queue class in Python 2.6

- by voipme

Let's assume I'm stuck using Python 2.6, and can't upgrade (even if that would help). I've written a program that uses the Queue class. My producer is a simple directory listing. My consumer threads pull a file from the queue, and do stuff with it. If the file has already been processed, I skip it. The processed list is generated before all of the threads are started, so it isn't empty. Here's some pseudo-code. import Queue, sys, threading processed = [] def consumer(): while True: file = dirlist.get(block=True) if file in processed: print "Ignoring %s" % file else: # do stuff here dirlist.task_done() dirlist = Queue.Queue() for f in os.listdir("/some/dir"): dirlist.put(f) max_threads = 8 for i in range(max_threads): thr = Thread(target=consumer) thr.start() dirlist.join() The strange behavior I'm getting is that if a thread encounters a file that's already been processed, the thread stalls out and waits until the entire program ends. I've done a little bit of testing, and the first 7 threads (assuming 8 is the max) stop, while the 8th thread keeps processing, one file at a time. But, by doing that, I'm losing the entire reason for threading the application. Am I doing something wrong, or is this the expected behavior of the Queue/threading classes in Python 2.6?

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html doctype adds whitespace ??

- by pstanton

can someone please explain to me why having a doctype of <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> and <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"> render the following block differently under firefox? <table style="border-collapse:collapse; margin:0; padding:0;"> <tr> <td style="border:1px solid red; margin:0; padding:0;"><img src="http://images.smh.com.au/2010/06/01/1533814/th_park-90x60.jpg" style="border:none; padding:0; margin:0;" /></td> </tr> </table> using 'Transitional', there is no white space below the image, using 'Strict' there is! 2nd question, using strict, is it at all possible to remove this whitespace?

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