higher order functions - Page 739

Scared of Calculus - Required to pass Differential Calculus as part of my Computer science major

- by ke3pup

Hi guys I'm finishing my Computer science degree in university but my fear of maths (lack of background knowledge) made me to leave all my maths units til' the very end which is now. i either take them on and pass or have to give up. I've passed all my programming units easily but knowing my poor maths skills won't do i've been staying clear of the maths units. I have to pass Differential Calculus and Linear Algebra first. With a help of book named "Linear Algebra: A Modern Introduction" i'm finding myself on track and i think i can pass the Linear Algebra unit. But with differential calculus i can't find a book to help me. They're either too advanced or just too simple for what i have to learn. The things i'm required to know for this units are: Set notation, the real number line, Complex numbers in cartesian form. Complex plane, modulus. Complex numbers in polar form. De Moivre’s Theorem. Complex powers and nth roots. Definition of ei? and ez for z complex. Applications to trigonometry. Revision of domain and range of a function Working in R3. Curves and surfaces. Functions of 2 variables. Level curves.Partial derivatives and tangent planes. The derivative as a difference quotient. Geometric significance of the derivative. Discussion of limit. Higher order partial derivatives. Limits of f(x,y). Continuity. Maxima and minima of f(x,y). The chain rule. Implicit differentiation. Directional derivatives and the gradient. Limit laws, l’Hoˆpital’s rule, composition law. Definition of sinh and cosh and their inverses. Taylor polynomials. The remainder term. Taylor series. Is there a book to help me get on track with the above? Being a student i can't buy too many books hence why i'm looking for a book that covers topics I need to know. The University library has a fairly limited collection which i took as loan but didn't find useful as it was too complex.

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Windows Service HTTPListener Memory Issue

- by crawshaws

Hi all, Im a complete novice to the "best practices" etc of writing in any code. I tend to just write it an if it works, why fix it. Well, this way of working is landing me in some hot water. I am writing a simple windows service to server a single webpage. (This service will be incorperated in to another project which monitors the services and some folders on a group of servers.) My problem is that whenever a request is recieved, the memory usage jumps up by a few K per request and keeps qoing up on every request. Now ive found that by putting GC.Collect in the mix it stops at a certain number but im sure its not meant to be used this way. I was wondering if i am missing something or not doing something i should to free up memory. Here is the code: Public Class SimpleWebService : Inherits ServiceBase 'Set the values for the different event log types. Public Const EVENT_ERROR As Integer = 1 Public Const EVENT_WARNING As Integer = 2 Public Const EVENT_INFORMATION As Integer = 4 Public listenerThread As Thread Dim HTTPListner As HttpListener Dim blnKeepAlive As Boolean = True Shared Sub Main() Dim ServicesToRun As ServiceBase() ServicesToRun = New ServiceBase() {New SimpleWebService()} ServiceBase.Run(ServicesToRun) End Sub Protected Overrides Sub OnStart(ByVal args As String()) If Not HttpListener.IsSupported Then CreateEventLogEntry("Windows XP SP2, Server 2003, or higher is required to " & "use the HttpListener class.") Me.Stop() End If Try listenerThread = New Thread(AddressOf ListenForConnections) listenerThread.Start() Catch ex As Exception CreateEventLogEntry(ex.Message) End Try End Sub Protected Overrides Sub OnStop() blnKeepAlive = False End Sub Private Sub CreateEventLogEntry(ByRef strEventContent As String) Dim sSource As String Dim sLog As String sSource = "Service1" sLog = "Application" If Not EventLog.SourceExists(sSource) Then EventLog.CreateEventSource(sSource, sLog) End If Dim ELog As New EventLog(sLog, ".", sSource) ELog.WriteEntry(strEventContent) End Sub Public Sub ListenForConnections() HTTPListner = New HttpListener HTTPListner.Prefixes.Add("http://*:1986/") HTTPListner.Start() Do While blnKeepAlive Dim ctx As HttpListenerContext = HTTPListner.GetContext() Dim HandlerThread As Thread = New Thread(AddressOf ProcessRequest) HandlerThread.Start(ctx) HandlerThread = Nothing Loop HTTPListner.Stop() End Sub Private Sub ProcessRequest(ByVal ctx As HttpListenerContext) Dim sb As StringBuilder = New StringBuilder sb.Append("<html><body><h1>Test My Service</h1>") sb.Append("</body></html>") Dim buffer() As Byte = Encoding.UTF8.GetBytes(sb.ToString) ctx.Response.ContentLength64 = buffer.Length ctx.Response.OutputStream.Write(buffer, 0, buffer.Length) ctx.Response.OutputStream.Close() ctx.Response.Close() sb = Nothing buffer = Nothing ctx = Nothing 'This line seems to keep the mem leak down 'System.GC.Collect() End Sub End Class Please feel free to critisise and tear the code apart but please BE KIND. I have admitted I dont tend to follow the best practice when it comes to coding.

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Really "wow" them in the interview

- by Juliet

Let me put it to you this way: I'm a top-notch programmer, but a notoriously bad interviewee. I've flunked 3 interviews consecutively because I get so nervous that my voice tightens at least 2 octaves higher and I start visibly shaking -- mind you, I can handle whatever technical questions the interviewer throws at me in that state, but I think it looks bad to come off as a quivering, squeaky-voiced young woman during a job interview. I've just got the personality type of a shy computer programmer. No matter how technical I am, I'm going to get passed up in favor of a smooth talker. I have another interview coming up shortly, and I want to really impress the company. Here are my trouble spots: What can I do to be less nervous during my interview? I always get really excited when I hear I have a face-to-face interview, but get more and more anxious as D-Day the interview approaches. My employers wants me to explain what I used to do at my prior employment. I'm a very chatty person and tend to talk/squeak for 10 minutes at a time. How long or short should I time my answers? On that note, when I'm explaining what I did at prior jobs, what exactly is my interviewer looking for? At some point, my interviewer will ask "do you have any questions for me while you're here?" I should, but what kinds of questions should I ask to show that I'm interested in being employed? My interviewer always asks why I'm looking for a new job. The real reason is that my present salary is $27K/yr [Edit to add: and I've yet to get a raise since I started], and I want to make more money -- otherwise the work environment is fine. How do I sugarcoat "I want to make more money" into something that sounds nicer? I have only one prior programmer job, and I've worked there for 18 months, but I have the skill of someone with 4 to 6 years of experience. What can I say to compete against applicants with more work experience? I took a low-paying $27K/yr programming job just to get my foot in IT, and I've been trying to leverage that job as a stepping stone to better opportunities. I get interviews because I consistently out-score senior-level developers in aptitude tests, and my desired salary range is right in the ballpark of what most companies want to offer. Unfortunately, while I've been a programming as a hobby for 10 years and I'm geared to graduate with my BA in Comp Sci in May '09, employers see me as a junior-level programmer with no degree. I want to prove them wrong and get a job that matches my skill level. I'd appreciate any advice anyone has to offer, especially if they can help me get a better job in the process.

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Streaming webcam video in Flash using MP4 encoding

- by Herms

One of the features of the Flash app I'm working on is to be able to stream a webcam to others. We're just using the built-in webcam support in Flash and sending it through FMS. We've had some people ask for higher quality video, but we're already using the highest quality setting we can in Flash (setting quality to 100%). My understanding is that in the newer flash players they added support for MPEG-4 encoding for the videos. I created a simple test Flex app to try and compare the video quality of the MP4 vs FLV encodings. However, I can't seem to get MP4 to work at all. According to the Flex documentation the only thing I need to do to use MP4 instead of FLV is prepend "mp4:" to the name of the stream when calling publish: Specify the stream name as a string with the prefix mp4: with or without the filename extension. The prefix indicates to the server that the file contains H.264-encoded video and AAC-encoded audio within the MPEG-4 Part 14 container format. When I try this nothing happens. I don't get any events raised on the client side, no exceptions thrown, and my logging on the server side doesn't show any streams starting. Here's the relevant code: // These are all defined and created within the class. private var nc:NetConnection; private var sharing:Boolean; private var pubStream:NetStream; private var format:String; private var streamName:String; private var camera:Camera; // called when the user clicks the start button private function startSharing():void { if (!nc.connected) { return; } if (sharing) { return; } if(pubStream == null) { pubStream = new NetStream(nc); pubStream.attachCamera(camera); } startPublish(); sharing = true; } private function startPublish():void { var name:String; if (this.format == "mp4") { name = "mp4:" + streamName; } else { name = streamName; } //pubStream.publish(name, "live"); pubStream.publish(name, "record"); }

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MaxReceivedMessageSize adjusted, but still getting the QuotaExceedException with WCF

- by djerry

Hey guys, First of all, i have read the "millions" of post on this site and some blogs/forum post on other websites, and no answer is solving my problem. I'm my app, there's a possibility to import a txt or csv file with data. In the case of the error, the file contains 444 rows (file is 14,5 kB). When i try to send it to the server to process it, i get an QuotaExceedException, telling me to increase MaxReceivedMessageSize. So i changed it to a much higher value, but i'm still getting the same exception. I'm using the same exact items for client and server in system.servicemodel in my config file. Config snippet : <system.serviceModel> <bindings> <netTcpBinding> <binding name="NetTcpBinding_IMonitoringSystemService" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" transactionFlow="false" transferMode="Buffered" transactionProtocol="OleTransactions" hostNameComparisonMode="StrongWildcard" listenBacklog="10" maxBufferPoolSize="2147483647" maxBufferSize="2147483647" maxConnections="500" maxReceivedMessageSize="2147483647"> <readerQuotas maxDepth="32" maxStringContentLength="100000" maxArrayLength="100000" maxBytesPerRead="100000" maxNameTableCharCount="100000" /> <reliableSession ordered="true" inactivityTimeout="00:10:00" enabled="false" /> <security mode="Message"> <transport clientCredentialType="Windows" protectionLevel="EncryptAndSign"> <extendedProtectionPolicy policyEnforcement="Never" /> </transport> <message clientCredentialType="Windows" /> </security> </binding> </netTcpBinding> </bindings> <client> <endpoint address="net.tcp://localhost:8000/Monitoring%20Server" binding="netTcpBinding" bindingConfiguration="NetTcpBinding_IMonitoringSystemService" contract="IMonitoringSystemService" >  <identity> <userPrincipalName value="DJERRYY\djerry" /> </identity> </endpoint> </client> </system.serviceModel> Can i use this sample for client and server config? And what should i not use in that case. Thanks in advance.

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Register all GUI components as Observers or pass current object to next object as a constructor argu

- by Jack

First, I'd like to say that I think this is a common issue and there may be a simple or common solution that I am unaware of. Many have probably encountered a similar problem. Thanks for reading. I am creating a GUI where each component needs to communicate (or at least be updated) by multiple other components. Currently, I'm using a Singleton class to accomplish this goal. Each GUI component gets the instance of the singleton and registers itself. When updates need to be made, the singleton can call public methods in the registered class. I think this is similar to an Observer pattern, but the singleton has more control. Currently, the program is set up something like this: class c1 { CommClass cc; c1() { cc = CommClass.getCommClass(); cc.registerC1( this ); C2 c2 = new c2(); } } class c2 { CommClass cc; c2() { cc = CommClass.getCommClass(); cc.registerC2( this ); C3 c3 = new c3(); } } class c3 { CommClass cc; c3() { cc = CommClass.getCommClass(); cc.registerC3( this ); C4 c4 = new c4(); } } etc. Unfortunately, the singleton class keeps growing larger as more communication is required between the components. I was wondering if it's a good idea to instead of using this singleton, pass the higher order GUI components as arguments in the constructors of each GUI component: class c1 { c1() { C2 c2 = new c2( this ); } } class c2 { C1 c1; c2( C1 c1 ) { this.c1 = c1 C3 c3 = new c3( c1, this ); } } class c3 { C1 c1; C2 c2; c3( C1 c1, C2 c2 ) { this.c1 = c1; this.c2 = c2; C4 c4 = new c4( c1, c2, this ); } } etc. The second version relies less on the CommClass, but it's still very messy as the private member variables increase in number and the constructors grow in length. Each class contains GUI components that need to communicate through CommClass, but I can't think of a good way to do it. If this seems strange or horribly inefficient, please describe some method of communication between classes that will continue to work as the project grows. Also, if this doesn't make any sense to anyone, I'll try to give actual code snippets in the future and think of a better way to ask the question. Thanks.

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EntityManagerFactory error on Websphere

- by neverland

I have a very weird problem. Have an application using Hibernate and spring.I have an entitymanger defined which uses a JNDI lookup .It looks something like this <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="persistenceUnitName" value="ConfigAPPPersist" /> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="showSql" value="true" /> <property name="generateDdl" value="false" /> <property name="databasePlatform" value="org.hibernate.dialect.Oracle9Dialect" /> </bean> </property> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.WebSphereDataSourceAdapter"> <property name="targetDataSource"> <bean class="org.springframework.jndi.JndiObjectFactoryBean"> <property name="jndiName" value="jdbc/pmp" /> </bean> </property> </bean> This application runs fine in DEV. But when we move to higher envs the team that deploys this application does it successfully initially but after a few restarts of the application the entitymanager starts giving this problem Caused by: javax.persistence.PersistenceException: [PersistenceUnit: ConfigAPPPersist] Unable to build EntityManagerFactory at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:677) at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:132) at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:224) at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:291) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1368) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1334) ... 32 more Caused by: org.hibernate.MappingException: **property mapping has wrong number of columns**: com.***.***.jpa.marketing.entity.MarketBrands.$performasure_j2eeInfo type: object Now you would say this is pretty obvious the entity MarketBrands is incorrect. But its not it maps to the table just fine. And the same code works on DEV. Also the jndi cannot be incorrect since it deploys and works fine initially but throws uo this error after a restart. This is weird and not very logical. But if someone has faced this or has any idea on what might be causing this Please!! help The persistence.xml for the persitence unit has very little <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="ConfigAPPPersist">  </persistence-unit> </persistence>

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Absolute reRendering using RichFaces

- by wheelie

Hey there, I am implementing copy/paste functionality for a complex object tree, this means you can copy an object and paste it where the object type is the same. Therefore I need to reRender the <a4j:commandLink>-s which are performing the paste action (so it will show on the GUI or not). Simplified example: Problem is that copy links are deep in the tree. How is it possible to reRender on a higher level in the component tree? (very)Simplified example: ... <h:form id="form1"> ... <a4j:commandLink value="Copy" reRender=":paste1, :paste2, :paste3" /> <a4j:commandLink id="paste1" value="Paste" rendered="#{myBean.myHashMap.key}" /> <a4j:outputPanel> <a4j:region renderRegionOnly="true"> <a4j:commandLink value="Copy" reRender=":paste1, :paste2, :paste3" /> <a4j:commandLink id="paste2" value="Paste" rendered="#{myBean.myHashMap.key}" /> </a4j:region> <a4j:outputPanel> <a4j:region renderRegionOnly="true"> <a4j:commandLink value="Copy" reRender=":paste1, :paste2, :paste3" /> <a4j:commandLink id="paste3" value="Paste" rendered="#{myBean.myHashMap.key}" /> </a4j:region> </a4j:outputPanel> </a4j:outputPanel> ... </h:form> Something like that. In practise this differs in that a rich:tree is displayed. Also, there can be multiple instances of the same paste link: object:0::paste3, object:1::paste3. private final String pasteIDs = ":xxPaste, ... , :xyPaste"; According to the RichFaces reference, putting the separator to the beginning of the ID means it is an "absolute" search expression, however this way i get the same result: only the 'local' paste link gets rerendered, the others not. Every copy-paste link pair is encapsulated in <a4j:region renderRegionOnly="true">, because it is necessary for other components to restrict the reRender to that region. Could this be blocking the reRender I want to make? Also I want to rerender exactly those paste links, so no other rerender action is triggered. Hope it is clear what i want to achieve. Any help would be appreciated! Daniel

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How can I get image data from QTKit without color or gamma correction in Snow Leopard?

- by Nick Haddad

Since Snow Leopard, QTKit is now returning color corrected image data from functions like QTMovies frameImageAtTime:withAttributes:error:. Given an uncompressed AVI file, the same image data is displayed with larger pixel values in Snow Leopard vs. Leopard. Currently I'm using frameImageAtTime to get an NSImage, then ask for the tiffRepresentation of that image. After doing this, pixel values are slightly higher in Snow Leopard. For example, a file with the following pixel value in Leopard: [0 180 0] Now has a pixel value like: [0 192 0] Is there any way to ask a QTMovie for video frames that are not color corrected? Should I be asking for a CGImageRef, CIImage, or CVPixelBufferRef instead? Is there a way to disable color correction altogether prior to reading in the video files? I've attempted to work around this issue by drawing into a NSBitmapImageRep with the NSCalibratedColroSpace, but that only gets my part of the way there: // Create a movie NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys : nsFileName, QTMovieFileNameAttribute, [NSNumber numberWithBool:NO], QTMovieOpenAsyncOKAttribute, [NSNumber numberWithBool:NO], QTMovieLoopsAttribute, [NSNumber numberWithBool:NO], QTMovieLoopsBackAndForthAttribute, (id)nil]; _theMovie = [[QTMovie alloc] initWithAttributes:dict error:&error]; // .... NSMutableDictionary *imageAttributes = [NSMutableDictionary dictionary]; [imageAttributes setObject:QTMovieFrameImageTypeNSImage forKey:QTMovieFrameImageType]; [imageAttributes setObject:[NSArray arrayWithObject:@"NSBitmapImageRep"] forKey: QTMovieFrameImageRepresentationsType]; [imageAttributes setObject:[NSNumber numberWithBool:YES] forKey:QTMovieFrameImageHighQuality]; NSError* err = nil; NSImage* image = (NSImage*)[_theMovie frameImageAtTime:frameTime withAttributes:imageAttributes error:&err]; // copy NSImage into an NSBitmapImageRep (Objective-C) NSBitmapImageRep* bitmap = [[image representations] objectAtIndex:0]; // Draw into a colorspace we know about NSBitmapImageRep *bitmapWhoseFormatIKnow = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:getWidth() pixelsHigh:getHeight() bitsPerSample:8 samplesPerPixel:4 hasAlpha:YES isPlanar:NO colorSpaceName:NSCalibratedRGBColorSpace bitmapFormat:0 bytesPerRow:(getWidth() * 4) bitsPerPixel:32]; [NSGraphicsContext saveGraphicsState]; [NSGraphicsContext setCurrentContext:[NSGraphicsContext graphicsContextWithBitmapImageRep:bitmapWhoseFormatIKnow]]; [bitmap draw]; [NSGraphicsContext restoreGraphicsState]; This does convert back to a 'Non color corrected' colorspace, but the color values NOT are exactly the same as what is stored in the Uncompressed AVI files we are testing with. Also this is much less efficient because it is converting from RGB - "Device RGB" - RGB. Also, I am working in a 64-bit application, so dropping down to the Quicktime-C API is not an option. Thanks for your help.

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firebug saying not a function

- by Aaron

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Memory not being freed, causing giant memory leak

- by Delan Azabani

In my Unicode library for C++, the ustring class has operator= functions set for char* values and other ustring values. When doing the simple memory leak test: #include <cstdio> #include "ucpp" main() { ustring a; for(;;)a="MEMORY"; } the memory used by the program grows uncontrollably (characteristic of a program with a big memory leak) even though I've added free() calls to both of the functions. I am unsure why this is ineffective (am I missing free() calls in other places?) This is the current library code: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring() { len = 0; values = (int *) malloc(0); } ustring(const ustring &input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; } ustring operator=(ustring input) { ustring result(input); free(values); len = input.len; values = input.values; return * this; } ustring(const char * input) { values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; input[i]; i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } len = s; } ustring operator=(const char * input) { ustring result(input); free(values); len = result.len; values = result.values; return * this; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } operator char * () { return this -> encode(); } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

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Multiple apks, single listing of app for Google TV and Android Phone/Tablet

- by Yash

I have an Android phone/tablet apk which is currently in Play store and has these settings in its manifest file: package="com.company.xyz" android:versionCode="0803010008" android:versionName="01.00.08" > <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="8" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" /> <uses-permission android:name="android.permission.WAKE_LOCK" /> <uses-library android:name="com.adobe.flashplayer" android:required="true" /> <supports-screens android:anyDensity="true" android:largeScreens="true" android:normalScreens="true" android:smallScreens="false" android:xlargeScreens="true" /> <uses-feature android:name="android.hardware.touchscreen" android:required="true" /> I had uploaded another apk for GoogleTV which has the same package name com.company.xyz as the previous apk and has the following settings in its manifest file: package="com.company.xyz" android:versionCode="1203010001" android:versionName="01.00.01" > <uses-sdk android:minSdkVersion="12" android:targetSdkVersion="12" /> <uses-permission android:name="android.permission.INTERNET" /> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <uses-permission android:name="android.permission.WAKE_LOCK" /> <uses-feature android:name="android.hardware.touchscreen" android:required="false" /> <uses-feature android:name="com.google.android.tv" android:required="true" /> <supports-screens android:largeScreens="true"/> <uses-configuration android:reqFiveWayNav="true" /> The Google TV apk never showed up on Play Store on GTV boxes, so I updated its manifest with the settings below and with everything else remaining the same package="com.company.xyz" android:versionCode="1203010002" android:versionName="01.00.02" > <supports-screens android:largeScreens="true" android:normalScreens="false" android:smallScreens="false" android:xlargeScreens="false" /> At this point, I am unable to save the app because of the Play Store error "Error: New APK version is lower than previous APK version" even though the GoogleTV apk has a higher version code than the Phone/Tablet version. Does anyone have a solution for this? Thanks!

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XSL - Unknown Error in FF media:content/@url

- by danit

I keep getting "Unknow Error occurred" when i try this in my XSLT: <table class="TEDtalks"> <xsl:for-each select="/rss/channel/item"> <tr> <td><xsl:value-of select="title"/></td> <td> <xsl:value-of select="media:content/@url" /> </td> </tr> </xsl:for-each> </table> The XML <rss> <channel> <item> <title>TEDTalks : Karen Armstrong: Let's revive the Golden Rule - Karen Armstrong (2009)</title> <itunes:author>Karen Armstrong</itunes:author> <description>Weeks from the Charter for Compassion launch, Karen Armstrong looks at religion's role in the 21st century: Will its dogmas divide us? Or will it unite us for common good? She reviews the catalysts that can drive the world's faiths to rediscover the Golden Rule.<img src="http://feeds.feedburner.com/~r/TEDTalks_video/~4/th6FBgvV22o" height="1" width="1"/></description> <itunes:subtitle>Karen Armstrong: Let's revive the Golden Rule</itunes:subtitle> <itunes:summary><![CDATA[Weeks from the Charter for Compassion launch, Karen Armstrong looks at religion's role in the 21st century: Will its dogmas divide us? Or will it unite us for common good? She reviews the catalysts that can drive the world's faiths to rediscover the Golden Rule.]]></itunes:summary> <link>http://feedproxy.google.com/~r/TEDTalks_video/~3/th6FBgvV22o/647</link> <guid isPermaLink="false">http://video.ted.com/talks/podcast/KarenArmstrong_2009G.mp4</guid> <pubDate>Tue, 29 Sep 2009 12:46:00 -0500</pubDate> <category>Higher Education</category> <itunes:explicit>no</itunes:explicit> <itunes:duration>00:09:54</itunes:duration> <itunes:keywords>TED</itunes:keywords> <media:content url="http://feedproxy.google.com/~r/TEDTalks_video/~5/XT8k_DqlzGc/KarenArmstrong_2009G.mp4" fileSize="33726021" type="video/mp4" />

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Agilent E4426B signal generator locks up during multiple GPIB *SAV operations

- by aspiehler

I have a test fixture with an Agilent E4426B RF signal generator connected to a PC via a National Instrument Ethernet-to-GPIB bridge. My software is attempting to sanitize the instrument by presetting it and then saving the current state to all of the memory locations writable via the standard SCPI command "*SAV x,y". The loop works to a point, but eventually the instrument responds with an error and continuously displays the "L" icon on the front display and a "Remote preset" message at the bottom. At that point it won't respond to any more remote commands and I have to either cycle power or press LOCAL, then PRESET at which point it takes about 3 minutes to finish presetting. At that point the "L" icon is still present and and the next GPIB command sent to the instrument causes it to report a -113 error (undefined header) in the instrument error queue. I fired up NI spy to see what was happening, and found that the error was happening at the same point in the loop - "*SAV 6,2" in this case. From NI Spy: Send (0, 0x0017, "*SAV 6,2", 8 (0x8), NLend (0,0x01)) Process ID: 0x00000520 Thread ID: 0x00000518 ibsta:0xc168 iberr: 6 ibcntl: 2(0x2) And here's the code from the instrument driver: int CHP_E4426b::Erase() { if ((m_StatusCode = Initialize()) != GPIB_SUCCESS) // basically just sends "*RST" return m_StatusCode; m_SaveState = "*SAV %d, %d"; for (int i=0; i < 10; i++) for (int j=0; j < 100; j++) { sprintf(m_CmdString, m_SaveState, j, i); if ((m_StatusCode = Send(m_CmdString, strlen(m_CmdString))) != GPIB_SUCCESS) return m_StatusCode; } return GPIB_SUCCESS; } I tried putting a small Sleep() delay (10-20 ms) at the end of the inner loop, and to my surprise it caused the error to show up earlier rather than later. 10 ms caused the loop to error out at 44,1 and 20 ms was even sooner. I've already eliminated faulty cabling or the instrument as the culprit. This same type of sequence works without any error on a higher end signal generator, so I'm tempted to chalk this up to a bug in the instrument's firmware.

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How to hide Amazon webstore default toolbar with Prototype?

- by melaos

Hi Guys, after playing around this morning, i've found that there's this default chunk of html code in the amazon webstore which will add a toolbar on top of the page. the html looks like below: <td id="wba_logo_bg"> <table class="logo" border="0" cellpadding="0" cellspacing="0" width="100%"> <tbody><tr><td align="left"></td> <td class="wba_account" style="padding: 5px;" align="right" valign="top"> <table border="0" cellpadding="0" cellspacing="0"> <form action="#" id="searchForm" method="get" name="searchForm"></form> <tbody><tr><td class="wba_account_link"> <a xmlns:xhtml="http://www.w3.org/1999/xhtml" class="myAccountNav" href="#" onclick="return false;">home</a></td> <td class="myAccountDots"></td> <td class="wba_account_link"><a class="myAccountNav" href="#" onclick="return false;">view cart</a></td> <td class="myAccountDots"></td><td class="wba_account_link"><a class="myAccountNav" href="#" onclick="return false;">my account</a></td> <td class="myAccountDots"></td><td class="wba_account_link"><a class="myAccountNav" href="#" onclick="return false;">order status</a></td> <td><img src="pageEditor_files/1_pixel.gif" hspace="7"></td> <td><input name="keyword" tabindex="1" type="text"></td> <td><img alt="Search" class="wba_search_btn" onclick="return false;" onkeyup="if (13==event.keyCode) searchForm.submit();" src="pageEditor_files/btn_search.gif" style="cursor: pointer;" tabindex="2" title="Search" hspace="3"> </td></tr></tbody> </table> </td></tr></tbody> </table> </td> and thus far i was able to use prototype to find those with the class name of wba_account_link and hide them via the codes below: function hideAmazonToolbar() { $("wba_logo_bg").hide(); }//end function but what i really want to do is preferably to hide the whole tbody instead, but with my limited prototype skills, i don't really know how to do this. can anybody point me to the right resources on how to get this done? thanks! EDIT Went higher up and apparently there's a td with an id, and solve it using prototype hide function! man, i love javascript framework :) thanks :)

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JavaScript Resource Management Design Pattern

- by Adam

As a web developer, a common problem I find myself tackling is waiting for something to load before doing something else. In particular, I often hide (using either display: none; or visibility: hidden; depending on the situation) elements while waiting for a background image or a CSS file to load. Consider this example from Last.FM. They overlay a semi-transparant PNG over each album art image so that it looks like it's inside a jewel-case. They let it load when it loads, so depending on your internet speed, you may see the art image by itself (without the overlay) temporarily. In this case, the album art looks fine without the jewel-case effect. But in similar situations, I have found that I don't want the user to see the site's design mangled as resources incrementally load. So, in rare cases I have hidden everything from the user until the whole kit and kaboodle has loaded. But this is often a pain to write out, and may force the user to wait for a pretty long time to see anything (besides "loading..." text). I can think of (and have used on occasion) some obvious solutions/compromises: Use some inline CSS so that as certain parts of the DOM load and render, they will immediately have the correct size/position/etc. Immediately render the navigation part of the site, so that if the user wanted to use the current page purely to get somewhere else, they don't have to wait for the rest to load. Load pixelated images first as placeholders for layout while lazy-loading higher quality images as replacements. Something quirky like using a cute animated gif to distract the user during a "loading..." phase. Show useful information as a reference while loading the full UI. (Something akin to Gmail Inbox Preview, etc.) (Sorry if my question was basically just asked and answered...) Despite all of these ideas, I still find myself hoping there are better ways of doing some of these things. So I guess what I'm looking for is some inspiration and/or any creative ways of dealing with this problem that you guys may have seen out in the wild.

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gcc/g++: error when compiling large file

- by Alexander

Hi, I have a auto-generated C++ source file, around 40 MB in size. It largely consists of push_back commands for some vectors and string constants that shall be pushed. When I try to compile this file, g++ exits and says that it couldn't reserve enough virtual memory (around 3 GB). Googling this problem, I found that using the command line switches --param ggc-min-expand=0 --param ggc-min-heapsize=4096 may solve the problem. They, however, only seem to work when optimization is turned on. 1) Is this really the solution that I am looking for? 2) Or is there a faster, better (compiling takes ages with these options acitvated) way to do this? Best wishes, Alexander Update: Thanks for all the good ideas. I tried most of them. Using an array instead of several push_back() operations reduced memory usage, but as the file that I was trying to compile was so big, it still crashed, only later. In a way, this behaviour is really interesting, as there is not much to optimize in such a setting -- what does the GCC do behind the scenes that costs so much memory? (I compiled with deactivating all optimizations as well and got the same results) The solution that I switched to now is reading in the original data from a binary object file that I created from the original file using objcopy. This is what I originally did not want to do, because creating the data structures in a higher-level language (in this case Perl) was more convenient than having to do this in C++. However, getting this running under Win32 was more complicated than expected. objcopy seems to generate files in the ELF format, and it seems that some of the problems I had disappeared when I manually set the output format to pe-i386. The symbols in the object file are by standard named after the file name, e.g. converting the file inbuilt_training_data.bin would result in these two symbols: binary_inbuilt_training_data_bin_start and binary_inbuilt_training_data_bin_end. I found some tutorials on the web which claim that these symbols should be declared as extern char _binary_inbuilt_training_data_bin_start;, but this does not seem to be right -- only extern char binary_inbuilt_training_data_bin_start; worked for me.

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Recursive N-way merge/diff algorithm for directory trees?

- by BobMcGee

What algorithms or Java libraries are available to do N-way, recursive diff/merge of directories? I need to be able to generate a list of folder trees that have many identical files, and have subdirectories with many similar files. I want to be able to use 2-way merge operations to quickly remove as much redundancy as possible. Goals: Find pairs of directories that have many similar files between them. Generate short list of directory pairs that can be synchronized with 2-way merge to eliminate duplicates Should operate recursively (there may be nested duplicates of higher-level directories) Run time and storage should be O(n log n) in numbers of directories and files Should be able to use an embedded DB or page to disk for processing more files than fit in memory (100,000+). Optional: generate an ancestry and change-set between folders Optional: sort the merge operations by how many duplicates they can elliminate I know how to use hashes to find duplicate files in roughly O(n) space, but I'm at a loss for how to go from this to finding partially overlapping sets between folders and their children. EDIT: some clarification The tricky part is the difference between "exact same" contents (otherwise hashing file hashes would work) and "similar" (which will not). Basically, I want to feed this algorithm at a set of directories and have it return a set of 2-way merge operations I can perform in order to reduce duplicates as much as possible with as few conflicts possible. It's effectively constructing an ancestry tree showing which folders are derived from each other. The end goal is to let me incorporate a bunch of different folders into one common tree. For example, I may have a folder holding programming projects, and then copy some of its contents to another computer to work on it. Then I might back up and intermediate version to flash drive. Except I may have 8 or 10 different versions, with slightly different organizational structures or folder names. I need to be able to merge them one step at a time, so I can chose how to incorporate changes at each step of the way. This is actually more or less what I intend to do with my utility (bring together a bunch of scattered backups from different points in time). I figure if I can do it right I may as well release it as a small open source util. I think the same tricks might be useful for comparing XML trees though.

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Silverlight with MVVM Inheritance: ModelView and View matching the Model

- by moonground.de

Hello Stackoverflowers! :) Today I have a special question on Silverlight (4 RC) MVVM and inheritance concepts and looking for a best practice solution... I think that i understand the basic idea and concepts behind MVVM. My Model doesn't know anything about the ViewModel as the ViewModel itself doesn't know about the View. The ViewModel knows the Model and the Views know the ViewModels. Imagine the following basic (example) scenario (I'm trying to keep anything short and simple): My Model contains a ProductBase class with a few basic properties, a SimpleProduct : ProductBase adding a few more Properties and ExtendedProduct : ProductBase adding another properties. According to this Model I have several ViewModels, most essential SimpleProductViewModel : ViewModelBase and ExtendedProductViewModel : ViewModelBase. Last but not least, according Views SimpleProductView and ExtendedProductView. In future, I might add many product types (and matching Views + VMs). 1. How do i know which ViewModel to create when receiving a Model collection? After calling my data provider method, it will finally end up having a List<ProductBase>. It containts, for example, one SimpleProduct and two ExtendedProducts. How can I transform the results to an ObservableCollection<ViewModelBase> having the proper ViewModel types (one SimpleProductViewModel and two ExtendedProductViewModels) in it? I might check for Model type and construct the ViewModel accordingly, i.e. foreach(ProductBase currentProductBase in resultList) if (currentProductBase is SimpleProduct) viewModels.Add( new SimpleProductViewModel((SimpleProduct)currentProductBase)); else if (currentProductBase is ExtendedProduct) viewModels.Add( new ExtendedProductViewModels((ExtendedProduct)currentProductBase)); ... } ...but I consider this very bad practice as this code doesn't follow the object oriented design. The other way round, providing abstract Factory methods would reduce the code to: foreach(ProductBase currentProductBase in resultList) viewModels.Add(currentProductBase.CreateViewModel()) and would be perfectly extensible but since the Model doesn't know the ViewModels, that's not possible. I might bring interfaces into game here, but I haven't seen such approach proven yet. 2. How do i know which View to display when selecting a ViewModel? This is pretty the same problem, but on a higher level. Ended up finally having the desired ObservableCollection<ViewModelBase> collection would require the main view to choose a matching View for the ViewModel. In WPF, there is a DataTemplate concept which can supply a View upon a defined DataType. Unfortunately, this doesn't work in Silverlight and the only replacement I've found was the ResourceSelector of the SLExtensions toolkit which is buggy and not satisfying. Beside that, all problems from Question 1 apply as well. Do you have some hints or even a solution for the problems I describe, which you hopefully can understand from my explanation? Thank you in advance! Thomas

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What to name column in database table that holds versioning number

- by rwmnau

I'm trying to figure out what to call the column in my database table that holds an INT to specific "record version". I'm currently using "RecordOrder", but I don't like that, because people think higher=newer, but the way I'm using it, lower=newer (with "1" being the current record, "2" being the second most current, "3" older still, and so on). I've considered "RecordVersion", but I'm afraid that would have the same problem. Any other suggestions? "RecordAge"? I'm doing this because when I insert into the table, instead of having to find out what version is next, then run the risk of having that number stolen from me before I write, I just insert insert with a "RecordOrder" of 0. There's a trigger on the table AFTER INSERT that increments all the "RecordOrder" numbers for that key by 1, so the record I just inserted becomes "1", and all others are increased by 1. That way, you can get a person's current record by selection RecordOrder=1, instead of getting the MAX(RecordOrder) and then selecting that. PS - I'm also open to criticism about why this is a terrible idea and I should be incrementing this index instead. This just seemed to make lookups much easier, but if it's a bad idea, please enlighten me! Some details about the data, as an example: I have the following database table: CREATE TABLE AmountDue ( CustomerNumber INT, AmountDue DECIMAL(14,2), RecordOrder SMALLINT, RecordCreated DATETIME ) A subset of my data looks like this: CustomerNumber Amountdue RecordOrder RecordCreated 100 0 1 2009-12-19 05:10:10.123 100 10.05 2 2009-12-15 06:12:10.123 100 100.00 3 2009-12-14 14:19:10.123 101 5.00 1 2009-11-14 05:16:10.123 In this example, there are three rows for customer 100 - they owed $100, then $10.05, and now they owe nothing. Let me know if I need to clarify it some more. UPDATE: The "RecordOrder" and "RecordCreated" columns are not available to the user - they're only there for internal use, and to help figure out which is the current customer record. Also, I could use it to return an appropriately-ordered customer history, though I could just as easily do that with the date. I can accomplish the same thing as an incrementing "Record Version" with just the RecordCreated date, I suppose, but that removes the convenience of knowing that RecordOrder=1 is the current record, and I'm back to doing a sub-query with MAX or MIN on the DateTime to determine the most recent record.

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Consolidating coding styles: Funcs, private method, single method classes

- by jdoig

Hi all, We currently have 3 devs with, some, conflicting styles and I'm looking for a way to bring peace to the kingdom... The Coders: Foo 1: Likes to use Func's & Action's inside public methods. He uses actions to alias off lengthy method calls and Func's to perform simple tasks that can be expressed in 1 or 2 lines and will be used frequently through out the code Pros: The main body of his code is succinct and very readable, often with only one or 2 public methods per class and rarely any private methods. Cons: The start of methods contain blocks of lambda rich code that other developers don't enjoy reading; and, on occasion, can contain higher order functions that other dev's REALLY don't like reading. Foo 2: Likes to create a private method for (almost) everything the public method will have to do . Pros: Public methods remain small and readable (to all developers). Cons: Private methods are numerous. With private methods that call into other private methods, that call into... etc, etc. Making code hard to navigate. Foo 3: Likes to create a public class with a, single, public method for every, non-trivial, task that needs performing, then dependency inject them into other objects. Pros: Easily testable, easy to understand (one object, one responsibility). Cons: project gets littered by classes, opening multiple class files to understand what code does makes navigation awkward. It would be great to take the best of all these techniques... Foo-1 Has really nice, readable (almost dsl-like) code... for the most part, except for all the Action and Func lambda shenanigans bulked together at the start of a method. Foo-3 Has highly testable and extensible code that just feels a bit "belt-&-braces" for some solutions and has some code-navigation niggles (constantly hitting F12 in VS and opening 5 other .cs files to find out what a single method does). And Foo-2... Well I'm not sure I like anything about the one-huge .cs file with 2 public methods and 12 private ones, except for the fact it's easier for juniors to dig into. I admit I grossly over-simplified the explanations of those coding styles; but if any one knows of any patterns, practices or diplomatic-manoeuvres that can help unite our three developers (without just telling any of them to just "stop it!") that would be great. From a feasibility standpoint : Foo-1's style meets with the most resistance due to some developers finding lambda and/or Func's hard to read. Foo-2's style meets with a less resistance as it's just so easy to fall into. Foo-3's style requires the most forward thinking and is difficult to enforce when time is short. Any ideas on some coding styles or conventions that can make this work?

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header confusion. Compiler not recognizing datatypes

- by numerical25

I am getting confused on why the compiler is not recognizing my classes. So I am just going to show you my code and let you guys decide. My error is this error C2653: 'RenderEngine' : is not a class or namespace name and it's pointing to this line std::vector<RenderEngine::rDefaultVertex> m_verts; Here is the code for rModel, in its entirety. It contains the varible. the class that holds it is further down. #ifndef _MODEL_H #define _MODEL_H #include "stdafx.h" #include <vector> #include <string> //#include "RenderEngine.h" #include "rTri.h" class rModel { public: typedef tri<WORD> sTri; std::vector<sTri> m_tris; std::vector<RenderEngine::rDefaultVertex> m_verts; std::wstring m_name; ID3D10Buffer *m_pVertexBuffer; ID3D10Buffer *m_pIndexBuffer; rModel( const TCHAR *filename ); rModel( const TCHAR *name, int nVerts, int nTris ); ~rModel(); float GenRadius(); void Scale( float amt ); void Draw(); //------------------------------------ Access functions. int NumVerts(){ return m_verts.size(); } int NumTris(){ return m_tris.size(); } const TCHAR *Name(){ return m_name.c_str(); } RenderEngine::cDefaultVertex *VertData(){ return &m_verts[0]; } sTri *TriData(){ return &m_tris[0]; } }; #endif at the very top of the code there is a header file #include "stdafx.h" that includes this // stdafx.h : include file for standard system include files, // or project specific include files that are used frequently, but // are changed infrequently // #include "targetver.h" #define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers // Windows Header Files: #include <windows.h> // C RunTime Header Files #include <stdlib.h> #include <malloc.h> #include <memory.h> #include <tchar.h> #include "resource.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #include "RenderEngine.h" #include "rModel.h" // TODO: reference additional headers your program requires here as you can see, RenderEngine.h comes before rModel.h #include "RenderEngine.h" #include "rModel.h" According to my knowledge, it should recognize it. But on the other hand, I am not really that great with organizing headers. Here my my RenderEngine Declaration. #pragma once #include "stdafx.h" #define MAX_LOADSTRING 100 #define MAX_LIGHTS 10 class RenderEngine { public: class rDefaultVertex { public: D3DXVECTOR3 m_vPosition; D3DXVECTOR3 m_vNormal; D3DXCOLOR m_vColor; D3DXVECTOR2 m_TexCoords; }; class rLight { public: rLight() { } D3DXCOLOR m_vColor; D3DXVECTOR3 m_vDirection; }; static HINSTANCE m_hInst; HWND m_hWnd; int m_nCmdShow; TCHAR m_szTitle[MAX_LOADSTRING]; // The title bar text TCHAR m_szWindowClass[MAX_LOADSTRING]; // the main window class name void DrawTextString(int x, int y, D3DXCOLOR color, const TCHAR *strOutput); //static functions static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam); static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam); bool InitWindow(); bool InitDirectX(); bool InitInstance(); int Run(); void ShutDown(); void AddLight(D3DCOLOR color, D3DXVECTOR3 pos); RenderEngine() { m_screenRect.right = 800; m_screenRect.bottom = 600; m_iNumLights = 0; } protected: RECT m_screenRect; //direct3d Members ID3D10Device *m_pDevice; // The IDirect3DDevice10 // interface ID3D10Texture2D *m_pBackBuffer; // Pointer to the back buffer ID3D10RenderTargetView *m_pRenderTargetView; // Pointer to render target view IDXGISwapChain *m_pSwapChain; // Pointer to the swap chain RECT m_rcScreenRect; // The dimensions of the screen ID3D10Texture2D *m_pDepthStencilBuffer; ID3D10DepthStencilState *m_pDepthStencilState; ID3D10DepthStencilView *m_pDepthStencilView; //transformation matrixs system D3DXMATRIX m_mtxWorld; D3DXMATRIX m_mtxView; D3DXMATRIX m_mtxProj; //pointers to shaders matrix varibles ID3D10EffectMatrixVariable* m_pmtxWorldVar; ID3D10EffectMatrixVariable* m_pmtxViewVar; ID3D10EffectMatrixVariable* m_pmtxProjVar; //Application Lights rLight m_aLights[MAX_LIGHTS]; // Light array int m_iNumLights; // Number of active lights //light pointers from shader ID3D10EffectVectorVariable* m_pLightDirVar; ID3D10EffectVectorVariable* m_pLightColorVar; ID3D10EffectVectorVariable* m_pNumLightsVar; //Effect members ID3D10Effect *m_pDefaultEffect; ID3D10EffectTechnique *m_pDefaultTechnique; ID3D10InputLayout* m_pDefaultInputLayout; ID3DX10Font *m_pFont; // The font used for rendering text // Sprites used to hold font characters ID3DX10Sprite *m_pFontSprite; ATOM RegisterEngineClass(); void DoFrame(float); bool LoadEffects(); void UpdateMatrices(); void UpdateLights(); }; The classes are defined within the class class rDefaultVertex { public: D3DXVECTOR3 m_vPosition; D3DXVECTOR3 m_vNormal; D3DXCOLOR m_vColor; D3DXVECTOR2 m_TexCoords; }; class rLight { public: rLight() { } D3DXCOLOR m_vColor; D3DXVECTOR3 m_vDirection; }; Not sure if thats good practice, but I am just going by the book. In the end, I just need a good way to organize it so that rModel recognizes RenderEngine. and if possible, the other way around.

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Audio/video streaming on Windows platform

- by bushtucker

I'm building an interactive language learning application to be used in a classroom environment. The idea is that a teacher should be able to talk to the students (=audio stream to all students), let students talk to each other (= audio P2P) in groups of two or more, let students watch a video coming from a the DVD player or coming from a media server. It should be possible to save the audio/video streams. The teacher should also be able to monitor, take-over or block the desktop of the students. The platform is Windows and it's a desktop application, no web application. The audio delay should be as minimal as poosible. Optionally a student sitting at home should be supported, but it's not a high priority. I am now finished with the classroom control part of the application (login, monitor, block, ...) and want to start the audio and video part. I've been evaluating several options like DirectX, GStreamer and SIP but now I have to make a decision. DirectX seems an obvious choice for the Windows platform, but it only lets me capture and playback audio and video. The encoding/decoding/network part I should do myself. GStreamer contains all kinds of options to capture/encode/stream/save audio and video streams. I've experimented a bit with it (ossbuild) and it does seem to involve a lot of trial and error to make something work: - microphone capture (via directsoundsrc) produces cracking noises on some computers - rtpL16 payloader didn't work well - streaming raw audio over the network only working at a sampling rate of 8000, no higher - there are a lot of errors when receiving mpeg4 video (bad I-frame), on some computers worse than others It is my impression that gstreamer is primary targetted at linux platforms. Development and support for the Windows platform seems to be a little behind. Nevertheless it's a powerful framework that could save me months and years of work. SIP seems to be able to do everything I want, but it is targeted towards telephony and IM. I don't know how flexible SIP is. It seems to me that the SIP layer would just be overhead as I already have a central (teacher) application that can control and setup all the streams. The interesting parts of frameworks like opalvoip and freeswitch are the actual audio/video capture, the encoding and transmission. Does anyone know how these interesting parts relate a framework like gstreamer? Are they easy to integrate into a custom application? Are they flexible enough? Does anyone have experience with all or one of these technologies? Maybe there are even other options I can look at? Many thanks for your advice

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Finding N contiguous zero bits in an integer to the left of the MSB position of another integer

- by James Morris

The problem is: given an integer val1 find the position of the highest bit set (Most Significant Bit) then, given a second integer val2 find a contiguous region of unset bits, with the minimum number of zero bits given by width to the left of the position (ie, in the higher bits). Here is the C code for my solution: typedef unsigned int t; unsigned const t_bits = sizeof(t) * CHAR_BIT; _Bool test_fit_within_left_of_msb( unsigned width, t val1, t val2, unsigned* offset_result) { unsigned offbit = 0; unsigned msb = 0; t mask; t b; while(val1 >>= 1) ++msb; while(offbit + width < t_bits - msb) { mask = (((t)1 << width) - 1) << (t_bits - width - offbit); b = val2 & mask; if (!b) { *offset_result = offbit; return true; } if (offbit++) /* this conditional bothers me! */ b <<= offbit - 1; while(b <<= 1) offbit++; } return false; } Aside from faster ways of finding the MSB of the first integer, the commented test for a zero offbit seems a bit extraneous, but necessary to skip the highest bit of type t if it is set. I have also implemented similar algorithms but working to the right of the MSB of the first number, so they don't require this seemingly extra condition. How can I get rid of this extra condition, or even, are there far more optimal solutions? Edit: Some background not strictly required. The offset result is a count of bits from the high bit, not from the low bit as maybe expected. This will be part of a wider algorithm which scans a 2D array for a 2D area of zero bits. Here, for testing, the algorithm has been simplified. val1 represents the first integer which does not have all bits set found in a row of the 2D array. From this the 2D version would scan down which is what val2 represents. Here's some output showing success and failure: t_bits:32 t_high: 10000000000000000000000000000000 ( 2147483648 ) --------- ----------------------------------- *** fit within left of msb test *** ----------------------------------- val1: 00000000000000000000000010000000 ( 128 ) val2: 01000001000100000000100100001001 ( 1091569929 ) msb: 7 offbit:0 + width: 8 = 8 mask: 11111111000000000000000000000000 ( 4278190080 ) b: 01000001000000000000000000000000 ( 1090519040 ) offbit:8 + width: 8 = 16 mask: 00000000111111110000000000000000 ( 16711680 ) b: 00000000000100000000000000000000 ( 1048576 ) offbit:12 + width: 8 = 20 mask: 00000000000011111111000000000000 ( 1044480 ) b: 00000000000000000000000000000000 ( 0 ) offbit:12 iters:10 ***** found room for width:8 at offset: 12 ***** ----------------------------------- *** fit within left of msb test *** ----------------------------------- val1: 00000000000000000000000001000000 ( 64 ) val2: 00010000000000001000010001000001 ( 268469313 ) msb: 6 offbit:0 + width: 13 = 13 mask: 11111111111110000000000000000000 ( 4294443008 ) b: 00010000000000000000000000000000 ( 268435456 ) offbit:4 + width: 13 = 17 mask: 00001111111111111000000000000000 ( 268402688 ) b: 00000000000000001000000000000000 ( 32768 ) ***** mask: 00001111111111111000000000000000 ( 268402688 ) offbit:17 iters:15 ***** no room found for width:13 ***** (iters is the count of iterations of the inner while loop)

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Reducer getting fewer records than expected

- by sathishs

We have a scenario of generating unique key for every single row in a file. we have a timestamp column but the are multiple rows available for a same timestamp in few scenarios. We decided unique values to be timestamp appended with their respective count as mentioned in the below program. Mapper will just emit the timestamp as key and the entire row as its value, and in reducer the key is generated. Problem is Map outputs about 236 rows, of which only 230 records are fed as an input for reducer which outputs the same 230 records. public class UniqueKeyGenerator extends Configured implements Tool { private static final String SEPERATOR = "\t"; private static final int TIME_INDEX = 10; private static final String COUNT_FORMAT_DIGITS = "%010d"; public static class Map extends Mapper<LongWritable, Text, Text, Text> { @Override protected void map(LongWritable key, Text row, Context context) throws IOException, InterruptedException { String input = row.toString(); String[] vals = input.split(SEPERATOR); if (vals != null && vals.length >= TIME_INDEX) { context.write(new Text(vals[TIME_INDEX - 1]), row); } } } public static class Reduce extends Reducer<Text, Text, NullWritable, Text> { @Override protected void reduce(Text eventTimeKey, Iterable<Text> timeGroupedRows, Context context) throws IOException, InterruptedException { int cnt = 1; final String eventTime = eventTimeKey.toString(); for (Text val : timeGroupedRows) { final String res = SEPERATOR.concat(getDate( Long.valueOf(eventTime)).concat( String.format(COUNT_FORMAT_DIGITS, cnt))); val.append(res.getBytes(), 0, res.length()); cnt++; context.write(NullWritable.get(), val); } } } public static String getDate(long time) { SimpleDateFormat utcSdf = new SimpleDateFormat("yyyyMMddhhmmss"); utcSdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles")); return utcSdf.format(new Date(time)); } public int run(String[] args) throws Exception { conf(args); return 0; } public static void main(String[] args) throws Exception { conf(args); } private static void conf(String[] args) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(); Job job = new Job(conf, "uniquekeygen"); job.setJarByClass(UniqueKeyGenerator.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); job.setMapperClass(Map.class); job.setReducerClass(Reduce.class); job.setInputFormatClass(TextInputFormat.class); job.setOutputFormatClass(TextOutputFormat.class); // job.setNumReduceTasks(400); FileInputFormat.addInputPath(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); } } It is consistent for higher no of lines and the difference is as huge as 208969 records for an input of 20855982 lines. what might be the reason for reduced inputs to reducer?

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