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• Best and easiest algorithm to search for a vertex on a Graph?

  - by Nazgulled

  Hi, After implementing most of the common and needed functions for my Graph implementation, I realized that a couple of functions (remove vertex, search vertex and get vertex) don't have the "best" implementation. I'm using adjacency lists with linked lists for my Graph implementation and I was searching one vertex after the other until it finds the one I want. Like I said, I realized I was not using the "best" implementation. I can have 10000 vertices and need to search for the last one, but that vertex could have a link to the first one, which would speed up things considerably. But that's just an hypothetical case, it may or may not happen. So, what algorithm do you recommend for search lookup? Our teachers talked about Breadth-first and Depth-first mostly (and Dikjstra' algorithm, but that's a completely different subject). Between those two, which one do you recommend? It would be perfect if I could implement both but I don't have time for that, I need to pick up one and implement it has the first phase deadline is approaching... My guess, is to go with Depth-first, seems easier to implement and looking at the way they work, it seems a best bet. But that really depends on the input. But what do you guys suggest?

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• How to handle media kept on a separate server (PHP)

  - by Sandman

  So, I have three server, and the idea was to keep all media (images, files, movies) on a media server. I never got around to do it but I think I probably should. So these are the three servers: WWW server DB server Media server Visitors obviously connect to the WWW server and currently image resizing and cache:ing is done on the WWW servers as the original files are kept there. So the idea for me is for image functions I have, that does all the image compositioning, resizing and cahceing would just pie the command over to the media server that would return ther path to the finnished file. What I don't know is how to handle functions such as file_exists() and figuring out image dimensions when needed before even any image management comes into play. Do I pipe all these commands to the other server, via HTTP? I was thinking along the ways of doing it this way: function image(##ARGS##){ if ($GLOBALS["media_host"] != "localhost"){ list ($src, $width, height) = file('http://$GLOBALS[media_host]/imgfunc.php?args=##ARGS##'); return "<img src='$src' height and width >"; } .... do other stuff here } Am I approaching this the wrong way? Is there a better way to do this?

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• Using $.get with jquery validation

  - by Jimmy McCarthy

  I'm trying to use the Jquery builtin validator on my page. The issue is that I have certain fields that only are required if the JobID (entered into another field) does not already exist in our database. I have a simple service which simply takes JobID and returns True or False based on whether the JobID exists, but I can't seem to get this information where I want it. Some sample code: $("#dep_form").validate({ rules: { JobID: { required: true, digits: true, minlength: 3 }, OrgName: { required: function(element) { //This field is required if the JobID is new. return $("#jobinfo").html().length==15; } } }, messages: { JobID: { required: "Enter a Job Number.", digits: "Only numbers are allowed in Job ID's.", minlength: "Job Number must be at least 3 digits" }, OrgName: { required: "Select a Practice from the dropdown list." } }, errorClass: "ui-state-error-input", errorLabelContainer: "#errorbox", errorElement: 'li', errorContainer: "#validation_errors", onfocusout: false, onkeyup: false, focusinvalid: false }; Currently, I'm using a lazy method to validate (shown above). However, I now have access to a service using the URL: var lookupurl = "/deposits/jobidvalidate/?q=" + $("#id_JobID").val() + "&t=" + new Date().getTime(); which is a page which will contain just the word True or False based on whether that given JobID exists. I've tried half a dozen different ways of setting variables and calling functions within functions and still cannot get a way to simply return the value of that page (which I've been trying to access with $.get() ) to my validator, so that required is set to true when the Job does not exist and false if the job already exists. Any suggestions? Thanks.

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• Need a design pattern for representing multiple information sources

  - by hsmit

  I'm building a Java application that retrieves information from differing information sources. I'm using a sensor, a set of RecordStores and a few online web services. In the basic application all these resources are loaded by default. Some of these sources are directly read in a separate thread (load database, read sensor etc.). From this basic application some functions are started that use these sources. The classes that contain these functions (usually combining multiple sources information) are currently paramterized with a set of resources like this: AppPart a1 = new AppPart(source1, source2, source3); I could also do it like this AppPart a1 = new AppPart(this); ..where I need to make my sources public in order to read them. I'm also thinking about a kind of stage/collection to publish all sources on, e.g: public SourceCollectionStage sStage = new SourceCollectionStage(); and later: sStage.getSensor(); .. for example. What do you guys think is the best or most often used way to do this? Btw: the user interface is often implemented by the specific funtion classes, not by the main class. Should I do this in another way?

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• a selector which has this selector together with a class selector

  - by Woho87

  Here is an analogy of my problem(a selector which has this selector together with a class selector): Let say that I selects all yellow(classes) div elements in a arbitrary HTML document. And I want each to check if the attribute is yes = 1. If the attribute 'yes' equals '1', then I want the child with class 'blue' have the attribute 'no' equals '1'; $('div .yellow').each(function(){ if($(this).attr('yes') == 1){ $(this '.blue:first-child').attr('no', 1);//This line needs to be fixed } }); I know that the line this.getElementsByClassName('blue')[0] fixes this problem. But in my real problem (not this analogy) I want to use addClass and removeClass which only functions with jQuery objects. It is to cumbersome to use other functions than addClass and removeClass. UPDATE: Here is a code snippet from my real problem. I got some problem with "this" in javascript. I want a invited button to have the className visible when I click on it. The button lies within a div element with className 'box'. I know that there are problem with 'this' on the code snippet. But I want the button and not the box to change to visible $('.Box').each(function(){ if($(this).attr('hasButton') != 1){ var invite = document.createElement('div'); invite.className = 'invite invisible'; invite.innerHTML = 'invite'; $(this).attr('hasButton', 1); this.appendChild(invite); invite.addEventListener('mouseover', function(event){ $('.invite', this).removeClass('invisible');//this line is not functioning $('.invite', this).addClass('visible');//neither this }, false); } });

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• How to improve Java performance on Informix for Windows

  - by Michal Niklas

  I have problem with performance of Java UDR functions on Informix on Windows. On this server I already have some functions in C and SPL. I chose one function to write it in those 3 languages and I measured performance of this function on test table. Function calculates some kind of checksum so it does not use any db libraries etc. only string and math operations. I observed performance on 30k records with SQL like: select function(txt) from _tmp_perf_test and I changed function to 'function_c, function_spl or function_java. My performance tests showed that C function is the fastest, SPL function is about 5 times slower, where Java is 100 (one hundred!) times slower than C. I checked it few times and 1:100 ratio didn't improve. I changed Java function to simply return length of the string but even this do not help so it looks, that there is general problem with Java function invocation, because there was no difference in time between Java function that calculate checksum and Java function that returns length of the string. I increased JVM_MAX_HEAP_SIZE to 128 and it not helped too. I use IBM Informix Dynamic Server Version 11.50.TC6DE. The same test on Linux server: IBM Informix Dynamic Server Version 11.50.FC6 show more "normal" results, i.e. Java is slower from C and SPL but only 2 to 5 times. What can I do to improve Java performance on Informix server on Windows? More info about Java on servers: c:\Informix\extend\krakatoa\jre\bin>java -version java version "1.5.0" Java(TM) 2 Runtime Environment, Standard Edition (build pwi32dev-20081129a (SR9-0 )) IBM J9 VM (build 2.3, J2RE 1.5.0 IBM J9 2.3 Windows Server 2003 x86-32 j9vmwi3223-20081129 (JIT enabled) J9VM - 20081126_26240_lHdSMr JIT - 20081112_1511ifx1_r8 GC - 200811_07) JCL - 20081129 [root@informix11 bin]# ./java -version java version "1.5.0" Java(TM) 2 Runtime Environment, Standard Edition (build pxa64devifx-20071025 (SR6b)) IBM J9 VM (build 2.3, J2RE 1.5.0 IBM J9 2.3 Linux amd64-64 j9vmxa6423-20071005 (JIT enabled) J9VM - 20071004_14218_LHdSMr JIT - 20070820_1846ifx1_r8 GC - 200708_10) JCL - 20071025

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• Problem on "Finding cursor position" function

  - by sanceray3

  Hi all, Few days ago, I have found a solution to obtain the cursor position on a div with contentedit="true". I use the solution defined on this web site : Finding cursor position in a contenteditable div function getCursorPos() { var cursorPos; if (window.getSelection) { var selObj = window.getSelection(); var selRange = selObj.getRangeAt(0); cursorPos = findNode(selObj.anchorNode.parentNode.childNodes, selObj.anchorNode) + selObj.anchorOffset; /* FIXME the following works wrong in Opera when the document is longer than 32767 chars */ } else if (document.selection) { var range = document.selection.createRange(); var bookmark = range.getBookmark(); /* FIXME the following works wrong when the document is longer than 65535 chars */ cursorPos = bookmark.charCodeAt(2) - 11; /* Undocumented function [3] */ } return cursorPos; } function findNode(list, node) { for (var i = 0; i < list.length; i++) { if (list[i] == node) { return i; } } return -1; } It functions well, but when I use html tags inside the div the pointer doesnt show the correct position. For example if I try to find cursor position on the <strong>cat</strong> is black, the function doesn't return me the good position. But if I try on the cat is black, it functions. Any ideas how to get the position with html tags ? Thanks for your help.

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• Execute code on assembly load

  - by Dmitriy Matveev

  I'm working on wrapper for some huge unmanaged library. Almost every of it's functions can call some error handler deeply inside. The default error handler writes error to console and calls abort() function. This behavior is undesirable for managed library, so I want to replace the default error handler with my own which will just throw some exception and let program continue normal execution after handling of this exception. The error handler must be changed before any of the wrapped functions will be called. The wrapper library is written in managed c++ with static linkage to wrapped library, so nothing like "a type with hundreds of dll imports" is present. I also can't find a single type which is used by everything inside wrapper library. So I can't solve that problem by defining static constructor in one single type which will execute code I need. I currently see two ways of solving that problem: Define some static method like Library.Initialize() which must be called one time by client before his code will use any part of the wrapper library. Find the most minimal subset of types which is used by every top-level function (I think the size of this subset will be something like 25-50 types) and add static constructors calling Library.Initialize (which will be internal in that scenario) to every of these types. I've read this and this questions, but they didn't helped me. Is there any proper ways of solving that problem? Maybe some nice hacks available?

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• What's the largest (most complex) PHP algorithm ever implemented in a single monolithic PHP script?

  - by Alex R

  I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The source needs to be in a single file. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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• Is there a PHP benchmark that meets these specific criteria? [closed]

  - by Alex R

  I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The PHP source needs to be in a single file. It should solve a real-world problem. No silly looping over empty methods etc. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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• use of assertions for type checking in php?

  - by user151841

  I do some checking of arguments in my classes in php using exception-throwing functions. I have functions that do a basic check ( ===, in_array etc ) and throw an exception on false. So I can do assertNumeric($argument, "\$argument is not numeric."); instead of if ( ! is_numeric($argument) ) { throw new Exception("\$argument is not numeric."); } Saves some typing I was reading in the comments of the php manual page on assert() that As noted on Wikipedia - "assertions are primarily a development tool, they are often disabled when a program is released to the public." and "Assertions should be used to document logically impossible situations and discover programming errors— if the 'impossible' occurs, then something fundamental is clearly wrong. This is distinct from error handling: most error conditions are possible, although some may be extremely unlikely to occur in practice. Using assertions as a general-purpose error handling mechanism is usually unwise: assertions do not allow for graceful recovery from errors, and an assertion failure will often halt the program's execution abruptly. Assertions also do not display a user-friendly error message." This means that the advice given by "gk at proliberty dot com" to force assertions to be enabled, even when they have been disabled manually, goes against best practices of only using them as a development tool So, am I 'doing it wrong'? What other/better ways of doing this are there?

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• Using Pragma in Oracle Package Body

  - by asalamon74

  I'd like to create an Oracle Package and two functions in it: A public function ( function_public ) and a private one ( function_private ). The public function calls the private one. I'd like to add the same pragma to the functions: WNDS, WNPS. Without the pragma I can create a code like this: CREATE OR REPLACE PACKAGE PRAGMA_TEST AS FUNCTION function_public(x IN VARCHAR2) RETURN VARCHAR2; END PRAGMA_TEST; CREATE OR REPLACE PACKAGE BODY PRAGMA_TEST AS FUNCTION function_private(y IN VARCHAR2) RETURN VARCHAR2 IS BEGIN -- code END; FUNCTION function_public(x IN VARCHAR2) RETURN VARCHAR2 IS BEGIN -- code -- here is a call for function_private -- code END; END PRAGMA_TEST; If I'd like to add WNDS, WNPS pragma to function_public I should also add the same pragma to function_private because function_public calls function_private. It seems to me pragma can be used only in the package declaration, and not in package body, so I have to declare function_private in the package as well: CREATE OR REPLACE PACKAGE PRAGMA_TEST AS FUNCTION function_private(y IN VARCHAR2) RETURN VARCHAR2; PRAGMA RESTRICT_REFERENCES( function_private, WNDS, WNPS); FUNCTION function_public(x IN VARCHAR2) RETURN VARCHAR2; PRAGMA RESTRICT_REFERENCES( function_public, WNDS, WNPS); END PRAGMA_TEST; CREATE OR REPLACE PACKAGE BODY PRAGMA_TEST AS FUNCTION function_private(y IN VARCHAR2) RETURN VARCHAR2 IS BEGIN -- code END; FUNCTION function_public(x IN VARCHAR2) RETURN VARCHAR2 IS BEGIN -- code -- here is a call for function_private -- code END; END PRAGMA_TEST; This solution makes my function_private public as well. Is there a solution to add pragma to a function which can be found only in the package body?

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• Possible to Inspect Innards of Core C# Functionality

  - by Nick Babcock

  I was struck today, with the inclination to compare the innards of Buffer.BlockCopy and Array.CopyTo. I am curious to see if Array.CopyTo called Buffer.BlockCopy behind the scenes. There is no practical purpose behind this, I just want to further my understanding of the C# language and how it is implemented. Don't jump the gun and accuse me of micro-optimization, but you can accuse me of being curious! When I ran ILasm on mscorlib.dll I received this for Array.CopyTo .method public hidebysig newslot virtual final instance void CopyTo(class System.Array 'array', int32 index) cil managed { // Code size 0 (0x0) } // end of method Array::CopyTo and this for Buffer.BlockCopy .method public hidebysig static void BlockCopy(class System.Array src, int32 srcOffset, class System.Array dst, int32 dstOffset, int32 count) cil managed internalcall { .custom instance void System.Security.SecuritySafeCriticalAttribute::.ctor() = ( 01 00 00 00 ) } // end of method Buffer::BlockCopy Which, frankly, baffles me. I've never run ILasm on a dll/exe I didn't create. Does this mean that I won't be able to see how these functions are implemented? Searching around only revealed a stackoverflow question, which Marc Gravell said [Buffer.BlockCopy] is basically a wrapper over a raw mem-copy While insightful, it doesn't answer my question if Array.CopyTo calls Buffer.BlockCopy. I'm specifically interested in if I'm able to see how these two functions are implemented, and if I had future questions about the internals of C#, if it is possible for me to investigate it. Or am I out of luck?

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• setcontext and makecontext to call a generic function pointer

  - by Simone Margaritelli

  In another question i had the problem to port the code unsigned long stack[] = { 1, 23, 33, 43 }; /* save all the registers and the stack pointer */ unsigned long esp; asm __volatile__ ( "pusha" ); asm __volatile__ ( "mov %%esp, %0" :"=m" (esp)); for( i = 0; i < sizeof(stack); i++ ){ unsigned long val = stack[i]; asm __volatile__ ( "push %0" :: "m"(val) ); } unsigned long ret = function_pointer(); /* restore registers and stack pointer */ asm __volatile__ ( "mov %0, %%esp" :: "m" (esp) ); asm __volatile__ ( "popa" ); To a 64bit platform and many guys told me i should use the setcontext and makecontext functions set instead due to the calling conversion differences between 32 and 64 bits and portability issues. Well, i really can't find any useful documentation online, or at least not the kind i need to implement this, so, how can i use those functions to push arguments onto the stack, call a generic function pointer, obtain the return value and then restore the registers?

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• Data Access Layer, Best Practices

  - by labratmatt

  I'm looking for input on the best way to refactor the data access layer (DAL) in my PHP based web app. I follow an MVC pattern: PHP/HTML/CSS/etc. views on the front end, PHP controllers/services in the middle, and a PHP DAL sitting on top of a relational database in the model. Pretty standard stuff. Things are working fine, but my DAL is getting large (codesmell?) and becoming a bit unwieldy. My DAL contains almost all of the logic to interface with my database and is full of functions that look like this: function getUser($user_id) { $statement = "select id, name from users where user_id=:user_id"; PDO builds statement and fetchs results as an array return $array_of_results_generated_by_PDO_fetch_method; } Notes: The logic in my controller only interacts with the model using functions like the above in the DAL I am not using a framework (I'm of the opinion that PHP is a templating language and there's no need to inject complexity via a framework) I generally use PHP as a procedural language and tend to shy away from its OOP approach (I enjoy OOP development but prefer to keep that complexity out of PHP) What approaches have you taken when your DAL has reached this point? Do I have a fundamental design problem? Do I simply need to chop my DAL into a number of smaller files (logically divide it)? Thanks.

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• Getting Argument Names In Ruby Reflection

  - by Joe Soul-bringer

  I would like to do some fairly heavy-duty reflection in the Ruby programming language. I would like to create a function which would return the names of the arguments of various calling functions higher up the call stack (just one higher would be enough but why stop there?). I could use Kernel.caller go to the file and parse the argument list but that would be ugly and unreliable. The function that I would like would work in the following way: module A def method1( tuti, fruity) foo end def method2(bim, bam, boom) foo end def foo print caller_args[1].join(",") #the "1" mean one step up the call stack end end A.method1 #prints "tuti,fruity" A.method2 #prints "bim, bam, boom" I would not mind using ParseTree or some similar tool for this task but looking at Parsetree, it is not obvious how to use it for this purpose. Creating a C extension like this is another possibility but it would be nice if someone had already done it for me. Edit2: I can see that I'll probably need some kind of C extension. I suppose that means my question is what combination of C extension would work most easily. I don't think caller+ParseTree would be enough by themselves. As far as why I would like to do this goes, rather than saying "automatic debugging", perhaps I should say that I would like to use this functionality to do automatic checking of the calling and return conditions of functions. Say def add x, y check_positive return x + y end Where check_positive would throw an exception if x and y weren't positive (obviously, there would be more to it than that but hopefully this gives enough motivation)

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• When *not* to use prepared statements?

  - by Ben Blank

  I'm re-engineering a PHP-driven web site which uses a minimal database. The original version used "pseudo-prepared-statements" (PHP functions which did quoting and parameter replacement) to prevent injection attacks and to separate database logic from page logic. It seemed natural to replace these ad-hoc functions with an object which uses PDO and real prepared statements, but after doing my reading on them, I'm not so sure. PDO still seems like a great idea, but one of the primary selling points of prepared statements is being able to reuse them… which I never will. Here's my setup: The statements are all trivially simple. Most are in the form SELECT foo,bar FROM baz WHERE quux = ? ORDER BY bar LIMIT 1. The most complex statement in the lot is simply three such selects joined together with UNION ALLs. Each page hit executes at most one statement and executes it only once. I'm in a hosted environment and therefore leery of slamming their servers by doing any "stress tests" personally. Given that using prepared statements will, at minimum, double the number of database round-trips I'm making, am I better off avoiding them? Can I use PDO::MYSQL_ATTR_DIRECT_QUERY to avoid the overhead of multiple database trips while retaining the benefit of parametrization and injection defense? Or do the binary calls used by the prepared statement API perform well enough compared to executing non-prepared queries that I shouldn't worry about it? EDIT: Thanks for all the good advice, folks. This is one where I wish I could mark more than one answer as "accepted" — lots of different perspectives. Ultimately, though, I have to give rick his due… without his answer I would have blissfully gone off and done the completely Wrong Thing even after following everyone's advice. :-) Emulated prepared statements it is!

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• How to use include within a function?

  - by mahks

  I have a large function that I wish to load only when it is needed. So I assume using include is the way to go. But I need several support functions as well -only used in go_do_it(). If they are in the included file I get a redeclare error. See example A If I place the support functions in an include_once it works fine, see Example B. If I use include_once for the func_1 code, the second call fails. -func_1 needs include -func_2 needs include_once Why does does include_once fail for func_1, does it get reloaded each time the function is called? Example A: <?php /* main.php */ go_do_it(); go_do_it(); function go_do_it(){ include 'func_1.php'; } ?> <?php /* func_1.php */ echo '<br>Doing it'; nested_func() function nested_func(){ echo ' in nest'; } ?> Example B: <?php /* main.php */ go_do_it(); go_do_it(); function go_do_it(){ include_once 'func_2.php'; include 'func_1.php'; } ?> <?php /* func_1.php */ echo '<br> - doing it'; nested_func(); ?> <?php /* func_2.php */ function nested_func(){ echo ' in nest'; } ?>

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• iPhone app rejection for using ICU (Unicode extensions)

  - by nickbit

  I received the following mail form Apple, considering my application: *Thank you for submitting your update to ??µ??es?a to the App Store. During our review of your application we found it is using private APIs, which is in violation of the iPhone Developer Program License Agreement section 3.3.1; "3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs." While your application has not been rejected, it would be appropriate to resolve this issue in your next update. The following non-public APIs are included in your application: u_isspace ubrk_close ubrk_current ubrk_first ubrk_next ubrk_open If you have defined methods in your source code with the same names as the above mentioned APIs, we suggest altering your method names so that they no longer collide with Apple's private APIs to avoid your application being flagged with future submissions. Please resolve this issue in your next update to ??µ??es?a. Sincerely, iPhone App Review Team* The functions mentioned in this mail are used in the ICU library (International Components for Unicode). Although my app is not rejected at this point, I don't feel very secure for the future of my app, because it relies heavily on the Unicode protocol and on this components in particular. Another thing is that I do not call these functions directly, but they are called by a custom 'sqlite' build (with FTS3 extensions enabled). Am I missing something here? Any suggestions?

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• In languages which create a new scope each time in a loop block, a new local copy of the local loop

  - by Jian Lin

  It seems that in language like C, Java, and Ruby (as opposed to Javascript), a new scope is created for each iteration of a loop block, and the local variable defined for the loop is actually made into a local variable every single time and recorded in this new scope? For example, in Ruby: p RUBY_VERSION $foo = [] (1..5).each do |i| $foo[i] = lambda { p i } end (1..5).each do |j| $foo[j].call() end the print out is: [MacBook01:~] $ ruby scope.rb "1.8.6" 1 2 3 4 5 [MacBook01:~] $ So, it looks like when a new scope is created, a new local copy of i is also created and recorded in this new scope, so that when the function is executed at a later time, the "i" is found in those scope chains as 1, 2, 3, 4, 5 respectively. Is this true? (It sounds like a heavy operation). Contrast that with p RUBY_VERSION $foo = [] i = 0 (1..5).each do |i| $foo[i] = lambda { p i } end (1..5).each do |j| $foo[j].call() end This time, the i is defined before entering the loop, so Ruby 1.8.6 will not put this i in the new scope created for the loop block, and therefore when the i is looked up in the scope chain, it always refer to the i that was in the outside scope, and give 5 every time: [MacBook01:~] $ ruby scope2.rb "1.8.6" 5 5 5 5 5 [MacBook01:~] $ I heard that in Ruby 1.9, i will be treated as a local defined for the loop even when there is an i defined earlier? The operation of creating a new scope, creating a new local copy of i each time through the loop seems heavy, as it seems it wouldn't have matter if we are not invoking the functions at a later time. So when the functions don't need to be invoked at a later time, could the interpreter and the compiler to C / Java try to optimize it so that there is not local copy of i each time?

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• Delphi - working with dll's for beginners

  - by doubleu

  Hi there, I'm a total newbie regarding to DLL. And I don't need to creat them I just need to use one. I've read some tutorials, but they weren't as helpful as I hoped. Here's the way I started: I've downloaded the SDK which I need to use (ESTOS Tapi Server). I read in the docs and spotted out the DLL which I need to use, which is the ENetSN.dll, and so I registered it. Next I've used the Dependency Walker to take a look at the DLL - and I was wondering because there are only these functions: DllCanUnloadNow, DllGetClassObject, DllRegisterServer and DllUnregisterServer, and these are not the functions mentioned in the docs. I think I have to call DllGetClassObject to get an object out of the DLL with which I can start to work. Unfortunately the tutorials I found doesn't mentioned how this is done (or I didn't understood it). There are also 3 exmaples delivered for VB and C++, but I wasn't able to 'translate' them into delphi. If somebody knows a tutorial where this is explained or could give me a pointer to the right direcetion, I would be very thankful .

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• What's the best way to transition to MVC coding?

  - by ggfan

  It's been around 5 months since I picked up a PHP book and started coding in PHP. At first, I created all my sites without any organizational plan or MVC. I soon found out that was a pain.. Then I started to read on stackoverflow on how to separate php and html and that's what I have been doing ever since. Ex: profile.php <--this file is HTML,css. I just echo the functions here. profile_functions.php <--this file is mostly PHP. has the functions. This is how I have been separating all my coding so far and now I feel I should move on and start MVC. But the problem is, I never used classes before and suck with them. And since MVC (such as cakephp and codeigniter) is all classes, that can't be good. My question: Is there any good books/sites/articles that teaches you how to code in MVC? I am looking for beginner beginner books :) I just started reading the codeigniter manuel and I think I am going to use that. When I looked at the example MVC, they use different PHP coding. When I start coding in MVC, would I have to learn a "new" way to code? Because right now I am coding in pure basic PHP.

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• C# COM Cross Thread problem

  - by user364676

  Hi, we're developing a software to control a scientific measuring device. it provides a COM-Interface defines serveral functions to set measurement parameters and fires an event when it measured data. in order to test our software, i'm implementing a simulation of that device. the com-object runs a loop which periodically fires the event. another loop in the client app should now setup up the com-simulator using the given functions. i created a class for measuring parameters which will be instanciated when setting up a new measurement. // COM-Object public class MeasurementParams { public double Param1; public double Param2; } public class COM_Sim : ICOMDevice { public MeasurementParams newMeasurement; IClient client; public int NewMeasurement() { newMeasurment = new MeasurementParam(); } public int SetParam1(double val) { // why is newMeasurement null when method is called from client loop newMeasurement.Param1 = val; } void loop() { while(true) { // fire event client.HandleEvent; } } } public class Client : IClient { ICOMDevice server; public int HandleEvent() { // handle this event server.NewMeasurement(); server.SetParam1(0.0); } void loop() { while(true) { // do some stuff... server.NewMeasurement(); server.SetParam1(0.0); } } } both of the loops run in independent threads. when server.NewMeasurement() is called, the object on the server is set to a new instance. but in the next function, the object is null again. do the same when handling the server-event, it works perfectly, because the method runs in the servers thread. how to make it work from client-thread as well. as the client is meant to be working with the real device, i cannot modify the interfaces given by the manufactor. also i need to setup measurements independent from the event-handler, which will be fired not regulary. i assume this problem related to multithreaded-COM behavior but i found nothing on this topic.

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• Writing fortran robust and "modern" code

  - by Blklight

  In some scientific environments, you often cannot go without FORTRAN as most of the developers only know that idiom, and there is lot of legacy code and related experience. And frankly, there are not many other cross-platform options for high performance programming ( C++ would do the task, but the syntax, zero-starting arrays, and pointers are too much for most engineers ;-) ). I'm a C++ guy but I'm stuck with some F90 projects. So, let's assume a new project must use FORTRAN (F90), but I want to build the most modern software architecture out of it. while being compatible with most "recent" compilers (intel ifort, but also including sun/HP/IBM own compilers) So I'm thinking of imposing: global variable forbidden, no gotos, no jump labels, "implicit none", etc. "object-oriented programming" (modules with datatypes + related subroutines) modular/reusable functions, well documented, reusable libraries assertions/preconditions/invariants (implemented using preprocessor statements) unit tests for all (most) subroutines and "objects" an intense "debug mode" (#ifdef DEBUG) with more checks and all possible Intel compiler checks possible (array bounds, subroutine interfaces, etc.) uniform and enforced legible coding style, using code processing tools C stubs/wrappers for libpthread, libDL (and eventually GPU kernels, etc.) C/C++ implementation of utility functions (strings, file operations, sockets, memory alloc/dealloc reference counting for debug mode, etc.) ( This may all seem "evident" modern programming assumptions, but in a legacy fortran world, most of these are big changes in the typical programmer workflow ) The goal with all that is to have trustworthy, maintainable and modular code. Whereas, in typical fortran, modularity is often not a primary goal, and code is trustworthy only if the original developer was very clever, and the code was not changed since then ! (i'm a bit joking here, but not much) I searched around for references about object-oriented fortran, programming-by-contract (assertions/preconditions/etc.), and found only ugly and outdated documents, syntaxes and papers done by people with no large-scale project involvement, and dead projects. Any good URL, advice, reference paper/books on the subject?

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• Objects in JavaScript defined and undefined at the same time (in a FireFox extension)

  - by Alexey Romanov

  I am chasing down a bug in a FireFox extension. I've finally managed to see it for myself (I've only had reports before) and I can't understand how what I saw is possible. One error message from my extension in the Error Console is "gBrowser is not defined". This by itself would be surprising enough, since the overlay is over browser.xul and navigator.xul, and I expect gBrowser to be available from both. Even worse is the actual place where it happens: line 101 of nextplease.js. That is, inside the function isTopLevelDocument, which is only called from onContentLoaded, which is only called from onLoad here: gBrowser.addEventListener(this.loadType, function (event) { nextplease.loadListener.onContentLoaded(event); }, true); So gBrowser is defined in onLoad, but somehow undefined in isTopLevelDocument. When I tried to actually use the extension, I got another error: "nextplease is not defined". The interesting thing is that it happened on lines 853 and 857. That is, inside the functions nextplease.getNextLink = function () { nextplease.getLink(window.content, nextplease.NextPhrasesMap, nextplease.NextImagesMap, nextplease.isNextRegExp, nextplease.NEXT_SEARCH_TYPE); } nextplease.getPrevLink = function () { nextplease.getLink(window.content, nextplease.PrevPhrasesMap, nextplease.PrevImagesMap, nextplease.isPrevRegExp, nextplease.PREV_SEARCH_TYPE); } So nextplease is somehow defined enough to call these functions, but isn't defined inside them. Finally, executing typeof(nextplease) in Execute JS returns "object". Same for gBrowser. How can this happen? Any ideas?

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