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  • Why is it useful to count the number of bits?

    - by Scorchin
    I've seen the numerous questions about counting the number of set bits in a insert type of input, but why is it useful? For those looking for algorithms about bit counting, look here: http://stackoverflow.com/questions/1517848/counting-common-bits-in-a-sequence-of-unsigned-longs http://stackoverflow.com/questions/472325/fastest-way-to-count-number-of-bit-transitions-in-an-unsigned-int http://stackoverflow.com/questions/109023/best-algorithm-to-count-the-number-of-set-bits-in-a-32-bit-integer

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  • Optimize CUDA with Thrust in a loop

    - by macs
    Given the following piece of code, generating a kind of code dictionary with CUDA using thrust (C++ template library for CUDA): thrust::device_vector<float> dCodes(codes->begin(), codes->end()); thrust::device_vector<int> dCounts(counts->begin(), counts->end()); thrust::device_vector<int> newCounts(counts->size()); for (int i = 0; i < dCodes.size(); i++) { float code = dCodes[i]; int count = thrust::count(dCodes.begin(), dCodes.end(), code); newCounts[i] = dCounts[i] + count; //Had we already a count in one of the last runs? if (dCounts[i] > 0) { newCounts[i]--; } //Remove thrust::detail::normal_iterator<thrust::device_ptr<float> > newEnd = thrust::remove(dCodes.begin()+i+1, dCodes.end(), code); int dist = thrust::distance(dCodes.begin(), newEnd); dCodes.resize(dist); newCounts.resize(dist); } codes->resize(dCodes.size()); counts->resize(newCounts.size()); thrust::copy(dCodes.begin(), dCodes.end(), codes->begin()); thrust::copy(newCounts.begin(), newCounts.end(), counts->begin()); The problem is, that i've noticed multiple copies of 4 bytes, by using CUDA visual profiler. IMO this is generated by The loop counter i float code, int count and dist Every access to i and the variables noted above This seems to slow down everything (sequential copying of 4 bytes is no fun...). So, how i'm telling thrust, that these variables shall be handled on the device? Or are they already? Using thrust::device_ptr seems not sufficient for me, because i'm not sure whether the for loop around runs on host or on device (which could also be another reason for the slowliness).

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  • Using Custom MapType with Google Maps API

    - by Pat Long - Munkii Yebee
    I realise there are a couple of examples such as Maoki's Add Your Own Custom Map and Mike Williams' [link text][Google Maps API Tutorial] however I have looked at these and still end up with a Grey box. The API will not call my "getTileUrl" callback function. This is the javascript I am using var map = new GMap2(document.getElementById("map")); map.setUIToDefault(); var copyCollection = new GCopyrightCollection('Map Data:'); var copyright = new GCopyright(1, new GLatLngBounds(new GLatLng(-90, -180), new GLatLng(90, 180)), 0, "©2006 RunwayFinder.com"); copyCollection.addCopyright(copyright); var tilelayers = [new GTileLayer(copyCollection, 3, 11)]; tilelayers[0].getTileUrl = function (a, b) { var z = 17 - b; var f = "http://localhost:25213/test.jpg?x=" + a.x + "&y=" + a.y + "&zoom=" + z + "&width=100&height=100"; return f; }; var custommap = new GMapType(tilelayers, new GMercatorProjection(12), "Chart", { errorMessage: "No chart data available" }); map.addMapType(custommap); Can anyone see what it is i am doing wrong?

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  • Printing a sideways triangle in java

    - by Will
    I'm trying to print a sideways triangle in java. If the user enters 5, the output should be: * *** ***** *** * If the user enters 6, the output should be: * *** ***** ***** *** * I've gotten it to work for the case when the user enters 5, 3, or 1 but my code seems to work for those three cases only. I was wondering if anyone could help me get my code working for more cases. Here it is: public void printArrow( int n ) { int asterisks = 1; for ( int i = 0; i <= n/2; i++ ) { for ( int j = i; j < asterisks; j++ ) { System.out.print( "*" ); } asterisks += 3; System.out.println(); } asterisks = asterisks / 2 - 2; for ( int i = 0; i < n/2; i++ ) { for ( int k = i; k < asterisks; k++ ) { System.out.print( "*" ); } if ( i == 1 ) { System.out.print( "*" ); } asterisks -= 2; System.out.println(); } }

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  • calculating min and max of 2-D array in c

    - by m2010
    This program to calculate sum,min and max of array elements Max value is the problem, it is always not true. void main(void) { int degree[3][2]; int min_max[][]; int Max=min_max[0][0]; int Min=min_max[0][0]; int i,j; int sum=0; clrscr(); for(i=0;i<3;i++) { for(j=0;j<2;j++) { printf("\n enter degree of student no. %d in subject %d:",i+1,j+1); scanf("%d",&degree[i][j]); } } for(i=0;i<3;i++) { for(j=0;j<2;j++) { printf("\n Student no. %d degree in subject no. %d is %d",i+1,j+1,degree[i][j]); } } for(i=0;i<3;i++) { sum=0; for(j=0;j<2;j++) { sum+=degree[i][j]; } printf("\n sum of degrees of student no. %d is %d",i+1,sum); min_max[i][j]=sum; if(min_max[i][j] <Min) { Min=min_max[i][j]; } else if(min_max[i][j]>Max) { Max=min_max[i][j]; } } printf("\nThe minimum sum of degrees of student no. %d is %d",i,Min); printf("\nThe maximum sum of degrees of student no. %d is %d",i,Max); getch(); }

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  • Passing Variable Length Arrays to a function

    - by David Bella
    I have a variable length array that I am trying to pass into a function. The function will shift the first value off and return it, and move the remaining values over to fill in the missing spot, putting, let's say, a -1 in the newly opened spot. I have no problem passing an array declared like so: int framelist[128]; shift(framelist); However, I would like to be able to use a VLA declared in this manner: int *framelist; framelist = malloc(size * sizeof(int)); shift(framelist); I can populate the arrays the same way outside the function call without issue, but as soon as I pass them into the shift function, the one declared in the first case works fine, but the one in the second case immediately gives a segmentation fault. Here is the code for the queue function, which doesn't do anything except try to grab the value from the first part of the array... int shift(int array[]) { int value = array[0]; return value; } Any ideas why it won't accept the VLA? I'm still new to C, so if I am doing something fundamentally wrong, let me know.

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  • Java OutOfMemoryError message changes when trying to create Arrays of different sizes

    - by Gordon
    In the question by DKSRathore How to simulate the Out Of memory : Requested array size exceeds VM limit some odd behavior was noted when creating an arrays. When creating an array of size Integer.MAX_VALUE an exception with the error java.lang.OutOfMemoryError Requested array size exceeds VM limit was thrown. However when an array was created with a size less than the max but still above the virtual machine memory limit the error message read java.lang.OutOfMemoryError: Java heap space. Testing further I managed to narrow down where the error messages changes. long[] l = new long[2147483645]; exceptions message reads - Requested array size exceeds VM limit long[] l = new long[2147483644]; exceptions message reads - Java heap space errors I increased my virtual machine memory and still produced the same result. Has anyone any idea why this happens? Some extra info: Integer.MAX_VALUE = 2147483647. Edit: Here's the code I used to find the value, might be helpful. int max = Integer.MAX_VALUE; boolean done = false; while (!done) { try { max--; // Throws an error long[] l = new long[max]; // Exit if an error is no longer thrown done = true; } catch (OutOfMemoryError e) { if (!e.getMessage().contains("Requested array size exceeds VM limit")) { System.out.println("Message changes at " + max); done = true; } } }

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  • Precision error on matrix multiplication

    - by Wam
    Hello all, Coding a matrix multiplication in my program, I get precision errors (inaccurate results for large matrices). Here's my code. The current object has data stored in a flattened array, row after row. Other matrix B has data stored in a flattened array, column after column (so I can use pointer arithmetic). protected double[,] multiply (IMatrix B) { int columns = B.columns; int rows = Rows; int size = Columns; double[,] result = new double[rows,columns]; for (int row = 0; row < rows; row++) { for (int col = 0; col < columns; col++) { unsafe { fixed (float* ptrThis = data) fixed (float* ptrB = B.Data) { float* mePtr = ptrThis + row*rows; float* bPtr = ptrB + col*columns; double value = 0.0; for (int i = 0; i < size; i++) { value += *(mePtr++) * *(bPtr++); } result[row, col] = value; } } } } } Actually, the code is a bit more complicated : I do the multiply thing for several chunks (so instead of having i from 0 to size, I go from localStart to localStop), then sum up the resulting matrices. My problem : for a big matrix I get precision error : NUnit.Framework.AssertionException: Error at (0,1) expected: <6.4209571409444209E+18> but was: <6.4207619776304906E+18> Any idea ?

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  • What could cause a Labwindows/CVI C program to hate the number 2573?

    - by Adam Bard
    Using Windows So I'm reading from a binary file a list of unsigned int data values. The file contains a number of datasets listed sequentially. Here's the function to read a single dataset from a char* pointing to the start of it: function read_dataset(char* stream, t_dataset *dataset){ //...some init, including setting dataset->size; for(i=0;i<dataset->size;i++){ dataset->samples[i] = *((unsigned int *) stream); stream += sizeof(unsigned int); } //... } Where read_dataset in such a context as this: //... char buff[10000]; t_dataset* dataset = malloc( sizeof( *dataset) ); unsigned long offset = 0; for(i=0;i<number_of_datasets; i++){ fseek(fd_in, offset, SEEK_SET); if( (n = fread(buff, sizeof(char), sizeof(*dataset), fd_in)) != sizeof(*dataset) ){ break; } read_dataset(buff, *dataset); // Do something with dataset here. It's screwed up before this, I checked. offset += profileSize; } //... Everything goes swimmingly until my loop reads the number 2573. All of a sudden it starts spitting out random and huge numbers. For example, what should be ... 1831 2229 2406 2637 2609 2573 2523 2247 ... becomes ... 1831 2229 2406 2637 2609 0xDB00000A 0xC7000009 0xB2000008 ... If you think those hex numbers look suspicious, you're right. Turns out the hex values for the values that were changed are really familiar: 2573 -> 0xA0D 2523 -> 0x9DB 2247 -> 0x8C7 So apparently this number 2573 causes my stream pointer to gain a byte. This remains until the next dataset is loaded and parsed, and god forbid it contain a number 2573. I have checked a number of spots where this happens, and each one I've checked began on 2573. I admit I'm not so talented in the world of C. What could cause this is completely and entirely opaque to me.

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  • How to improve IntelliJ code editor speed?

    - by Hoàng Long
    I am using IntelliJ (Community Edition) for several months, and at first I'm pleased about its speed & simplicity. But now, after upgrading to version 10, it's extremely slow. Sometimes I click a file then it takes 5 - 15 seconds to open that file (it freeze for that time). I don't know if I have done anything which cause that: I have installed 2 plugins(regex, sql), and have 2 versions of IntelliJ on my machine (now the version 9 removed, only version 10 remains). Is there any tips to improve speed of code editor, in general, or specifically IntelliJ? I have some experience when using IntelliJ: 1. Should open IntelliJ a while before working, cause it needs time for indexing. Don't open too many code tabs Open as less other program as possible. I'm using 2 GB RAM WinXP, and it just seems fairly enough for Java, IntelliJ & Chrome at the same time.

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  • fgets in c doesn't return a portion of an string

    - by Marc
    Hi! I'm totally new in C, and I'm trying to do a little application that searches a string into a file, my problem is that I need to open a big file (more than 1GB) with just one line inside and fgets return me the entire file (I'm doing test with a 10KB file). actually this is my code: #include <stdio.h> #include <string.h> int main(int argc, char *argv[]) { char *search = argv[argc-1]; int retro = strlen(search); int pun = 0; int sortida; int limit = 10; char ara[20]; FILE *fp; if ((fp = fopen ("SEARCHFILE", "r")) == NULL){ sortida = -1; exit (1); } while(!feof(fp)){ if (fgets(ara, 20, fp) == NULL){ break; } //this must be a 20 bytes line, but it gets the entyre 10Kb file printf("%s",ara); } sortida = 1; if(fclose(fp) != 0){ sortida = -2; exit (1); } return 0; } What can I do to find an string into a file? I'v tried with GREP but it don't helps, because it returns the position:ENTIRE_STRING. I'm open to ideas. Thanks in advance!

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  • Read variable-length records from a buffer - weird memory issues

    - by bsg
    Hi, I'm trying to implement an i/o intensive quicksort (C++ qsort) on a very large dataset. In the interests of speed, I'd like to read in a chunk of data at a time into a buffer and then use qsort to sort it inside the buffer. (I am currently working with text files but would like to move to binary soon.) However, my data is composed of variable-length records, and qsort needs to be told the length of the record in order to sort. Is there any way to standardize this? The only thing I could think of was rather convoluted: my program currently reads from the buffer until it hits a linefeed character ('10' in ascii), transferring each character over to another array. When it finds a linefeed (the delimiter in the input file), it fills the number of spaces remaining in the buffer for that record (record size is set to 30) with null characters. This way, I should end up with a buffer full of fixed-size records to give qsort. I know there are several problems with my approach, one being that it's just clumsy, another that the record size might conceivably be larger than 30, but is generally much less. Is there a better way of doing this? As well, my current code doesn't even work. When I debug it, it seems to be transferring characters from one buffer to the other, but when I try to print out the buffer, it contains only the first record. Here is my code: FILE *fp; unsigned char *buff; unsigned char *realbuff; FILE *inputFiles[NUM_INPUT_FILES]; buff = (unsigned char *) malloc(2048); realbuff = (unsigned char *) malloc(NUM_RECORDS * RECORD_SIZE); fp = fopen("postings0.txt", "r"); if(fp) { fread(buff, 1, 2048, fp); /*for(int i=0; i <30; i++) cout << buff[i] <<endl;*/ int y=0; int recordcounter = 0; //cout << buff; for(int i=0;i <100; i++) { if(buff[i] != char(10)) { realbuff[y] = buff[i]; y++; recordcounter++; } else { if(recordcounter < RECORD_SIZE) for(int j=recordcounter; j < RECORD_SIZE;j++) { realbuff[y] = char(0); y++; } recordcounter = 0; } } cout << realbuff <<endl; cout << buff; } else cout << "sorry"; Thank you very much, bsg

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  • Binding ListBox ItemCount to IvalueConverter

    - by Ben
    Hi All, I am fairly new to WPF so forgive me if I am missing something obvious. I'm having a problem where I have a collection of AggregatedLabels and I am trying to bind the ItemCount of each AggregatedLabel to the FontSize in my DataTemplate so that if the ItemCount of an AggregatedLabel is large then a larger fontSize will be displayed in my listBox etc. The part that I am struggling with is the binding to the ValueConverter. Can anyone assist? Many thanks! XAML Snippet <DataTemplate x:Key="TagsTemplate"> <WrapPanel> <TextBlock Text="{Binding Name, Mode=Default}" TextWrapping="Wrap" FontSize="{Binding ItemCount, Converter={StaticResource CountToFontSizeConverter}, Mode=Default}" Foreground="#FF0D0AF7"/> </WrapPanel> </DataTemplate> <ListBox x:Name="tagsList" ItemsSource="{Binding AggregatedLabels, Mode=Default}" ItemTemplate="{StaticResource TagsTemplate}" Style="{StaticResource tagsStyle}" Margin="200,10,16.171,11.88" /> AggregatedLabel Collection using (DB2DataReader dr = command.ExecuteReader()) { while (dr.Read()) { AggregatedLabelModel aggLabel = new AggregatedLabelModel(); aggLabel.ID = Convert.ToInt32(dr["LABEL_ID"]); aggLabel.Name = dr["LABEL_NAME"].ToString(); LabelData.Add(aggLabel); } } Converter public class CountToFontSizeConverter : IValueConverter { #region IValueConverter Members public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { const int minFontSize = 6; const int maxFontSize = 38; const int increment = 3; int count = (int)value; if ((minFontSize + count + increment) < maxFontSize) { return minFontSize + count + increment; } return maxFontSize; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } #endregion } AggregatedLabel Class public class AggregatedLabelModel { public int ID { get; set; } public string Name { get; set; } } CollectionView ListCollectionView labelsView = new ListCollectionView(LabelData); labelsView.GroupDescriptions.Add(new PropertyGroupDescription("Name"));

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  • UIView Obscuring Other Views

    - by Matt Long
    I cannot figure out what is obscuring my buttons. The first image shows the buttons that I want to click. They are clickable while the view is contracted like this, but when the view is expanded like in the second image, the buttons are no longer clickable. There seems to be another view obscuring the buttons. Any thoughts on what might be causing that? If not, any idea how I can figure out what view is getting the tap events when I tap in that area? Thanks. -Matt

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  • Quartz 2D or OpenGL ES? Pros and cons in the long term, possibility of migration to other platforms.

    - by fspirit
    Hi all! I'm having a hard time deciding whether to go with Quartz2D or OpenGL for an iPad game. It will be 2D mostly, but effect-intense (simultaneous lighting effects for 10-30 objects, 10-20 simultaneous animations on the screen). So far, assuming i'm equally dumb in both technologies and have to learn them from the ground, i came to this list. (I've read several topics here, on SO, with names like "Quartz or OpenGL", but i'm still left with some questions) Quartz: Better time-to-market, because of ready to use absractions like UIView, UIImageView, CoreAnimation abstractions Open GL ES Closer to hardware, thus, performance is better. App, implemented with OpenGL ES can be easier migrated to Android, MeeGo, Windows Phone, etc. My questions are: How time will it take to rewrite Quartz 2d app to use OpenGL? Lets say it took me 2 man-month to write Quartz app, how much time will i need to rewrite it? (Please, just some subjective opinions, i'll try to summarize them somehow) Regarding the ease of migration to other platforms, when using OpenGL, is it really so? Or efforts when migrating Quartz app from iPhoneOS to Android will be not so much bigger, compared to OpenGL app migration? (Ease of migration is quite important criterion) Regarding OpenGL, should i go with OpenGL 1.1 or 2.0, concerning migration? (Android supports 2.0 through NDK, but dont know whether NDK's use will increase or decrease migration efforts)

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  • How can I optimize the import of this dataset in mysql?

    - by GeoffreyF67
    I've got the following table schema: CREATE TABLE `alexa` ( `id` int(10) unsigned NOT NULL, `rank` int(10) unsigned NOT NULL, `domain` varchar(63) NOT NULL, `domainStatus` varchar(6) DEFAULT NULL, PRIMARY KEY (`rank`), KEY `domain` (`domain`), KEY `id` (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 It takes several minutes to import the data. To me that seems rather slow as we're only talking about a million rows of data. What can I do to optimize the insert of this data? (already using disable keys) G-Man

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  • how to show integer values in JComboBox?

    - by Edan
    Hello, I would like to know how to set a JComboBox that contain integers values that I could save. Here is the definitions of values: public class Item { private String itemDesc; private int itemType; public static int ENTREE=0; public static int MAIN_MEAL=1; public static int DESSERT=2; public static int DRINK=3; private float price; int[] itemTypeArray = { ENTREE, MAIN_MEAL, DESSERT, DRINK }; Object[][] data = {{itemDesc, new Integer(itemType), new Float(price)}}; . . . } Now, I want the add a JComboBox that the user will choose 1 of the items (ENTREE, MAIN_MEAL...) and then I could set the number as an Integer. I know that JComboBox need to be something like that: JComboBox combo = new JComboBox(itemTypeArray.values()); JOptionPane.showMessageDialog( null, combo,"Please Enter Item Type", `JOptionPane.QUESTION_MESSAGE);` What am I doing wrong?

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  • How can I export an array from Dynamics AX 2009 via c#?

    - by Steve Homer
    I'm pulling data from Dynamics AX 2009 from c# using the following code snippet. This works fine, except for those cases where the underlying field type is a dimension. I want to be able to "flatten" array types when I return them but can't see any way to do this. Any ideas anyone? axRecord = ax.CreateAxaptaRecord(tableName); axRecord.ExecuteStmt(strQuery); // Loop through the set of retrieved records. using (StreamWriter sw = File.CreateText(path)) { AxaptaObject axDictTable = ax.CreateAxaptaObject("SysDictTable",axRecord.get_Field("tableid")); outputRow = null; List<int> ids = new List<int>(); for (int i = 1; i <= (int)axDictTable.Call("fieldCnt"); i++) { AxaptaObject axDictField = ax.CreateAxaptaObject("DictField", axRecord.get_Field("tableid"), axDictTable.Call("fieldCnt2ID", i)); outputRow += ((string)axDictField.Call("Name")) + ","; ids.Add((int)axDictTable.Call("fieldCnt2ID", i)); } sw.WriteLine(outputRow); while (axRecord.Found) { outputRow = null; foreach(int i in ids) outputRow += axRecord.get_Field(i).ToString().Replace(",", "") + ","; sw.WriteLine(outputRow); axRecord.Next(); } }

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  • Rails : fighting long http response times with ajax. Is it a good idea? Please, help with implementa

    - by baranov
    Hi, everybody! I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem. I'm writing a web site which is supposed to display almost realtime stock chart. Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable. I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point. I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%". And so on, until all the data is ready and the server displays the requested chart. Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before. I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself. Thanks for your time!

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  • Strange casting problem with tm structure

    - by egiakoum1984
    I have the following casting problem when my data structure sSpecificData contains a field of type tm: typedef struct { unsigned char data[10000]; } sDataBuffer; typedef struct { int m_Id; sDataBuffer m_Data; } sData; typedef struct { int m_value1; int m_value2; tm m_Date; } sSpecificData; const int SPECIFIC_SVC_DATA_SIZE = sizeof(sSpecificData); typedef struct { int m_Id; sSpecificData m_Data; } sMyData; int main(void) { sData svc; sMyData* ptr1 = (sMyData*) &svc; sSpecificData* ptr2; ptr2 = (sSpecificData*) &svc.m_Data; ptr1->m_Data.m_value1 = 90; ptr1->m_Data.m_value2 = 80; cout << ptr1->m_Data.m_value1 << endl; cout << ptr1->m_Data.m_value2 << endl; cout << ptr2->m_value1 << endl; cout << ptr2->m_value2 << endl; return 0; } Without the field "tm m_Date;" as part of the sSpecificData, the output is correct: 90 80 90 80 With the field "tm m_Date;" as part of the sSpecificData, the output is wrong: 90 80 0 <-- ! 90 <-- ! Is there any idea why my example doesn't work when there is field of type tm as part of the sSpecificData? Thanks!

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  • Did I find a bug in PHP's `crypt()`?

    - by Nathan Long
    I think I may have found a bug in PHP's crypt() function under Windows. However: I recognize that it's probably my fault. PHP is used by millions and worked on by thousands; my code is used by tens and worked on by me. (This argument is best explained on Coding Horror.) So I'm asking for help: show me my fault. I've been trying to find it for a few days now, with no luck. The setup I'm using a Windows server installation with Apache 2.2.14 (Win32) and PHP 5.3.2. My development box runs Windows XP Professional; the 'production' server (this is an intranet setup) runs Windows Storage Server 2003. The problem happens on both. I don't see anything in php.ini related to crypt(), but will happily answer questions about my config. The problem Several scripts in my PHP app occasionally hang: the page sits there on 'waiting for localhost' and never finishes. Each of these scripts uses crypt to hash a user's password before storing it in the database, or, in the case of the login page, to hash the entered password before comparing it to the version stored in the database. Since the login page is the simplest, I focused on it for testing. I repeatedly logged in, and found that it would hang maybe 4 out of 10 times. As an experiment, I changed the login page to use the plain text password and changed my password in the database to its plain text version. The page stopped hanging. I saw that PHP's latest version lists this bugfix: Fixed bug #51059 (crypt crashes when invalid salt are [sic] given). So I created a very simple test script, as follows, using the same salt given in an official example: $foo = crypt('rasmuslerdorf','r1'); echo $foo; This page, too, will hang, if I reload it like crazy. I only see it hanging in Chrome, but regardless of browser, the effect on Apache is the same. Effect on Apache When these pages hang, Apache's server-status page (which I explained here, regarding a different problem) increments the number of requests being processed and decrements the number of idle workers. The requests being processed almost all have a status of 'Sending Reply,' though sometimes for a moment they will show either 'Reading request' or 'keepalive (read).' Eventually, Apache may crash. When it does, the Windows crash report looks like this: szAppName: httpd.exe szAppVer: 2.2.14.0 szModName: php5ts.dll szModVer: 5.3.1.0 // OK, this report was before I upgraded to PHP 5.3.2, // but that didn't fix it offset: 00a2615 Is it my fault? I'm tempted to file a bug report to PHP on this. The argument against it is, as stated above, that bugs are nearly always my fault. However, my argument in favor of 'it's PHP's fault' is: I'm using Windows, whereas most servers use Linux (I don't get to choose this), so the chances are greater that I've found an edge case There was recently a bug with crypt(), so maybe it still has issues I have made the simplest test case I can, and I still have the problem Can anyone duplicate this? Can you suggest where I've gone wrong? Should I file the bug after all? Thanks in advance for any help you may give.

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  • Playing Multiple sounds at the same time in Android

    - by Wrapper
    I am unable to use the following to code to play multiple sounds/beeps simultaneously. In my onclicklistener I have added ... public void onClick(View v) { mSoundManager.playSound(1); mSoundManager.playSound(2); } ... But this plays only one sound at a time, sound with index 1 followed by sound with index 2. How can I play atleast 2 sounds simultaneously using this code whenever there is an onClick() event? public class SoundManager { private SoundPool mSoundPool; private HashMap<Integer, Integer> mSoundPoolMap; private AudioManager mAudioManager; private Context mContext; public SoundManager() { } public void initSounds(Context theContext) { mContext = theContext; mSoundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 0); mSoundPoolMap = new HashMap<Integer, Integer>(); mAudioManager = (AudioManager)mContext.getSystemService(Context.AUDIO_SERVICE); } public void addSound(int Index,int SoundID) { mSoundPoolMap.put(1, mSoundPool.load(mContext, SoundID, 1)); } public void playSound(int index) { int streamVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC); mSoundPool.play(mSoundPoolMap.get(index), streamVolume, streamVolume, 1, 0, 1f); } public void playLoopedSound(int index) { int streamVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC); mSoundPool.play(mSoundPoolMap.get(index), streamVolume, streamVolume, 1, -1, 1f); } }

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  • Accidental Complexity in OpenSSL HMAC functions

    - by Hassan Syed
    SSL Documentation Analaysis This question is pertaining the usage of the HMAC routines in OpenSSL. Since Openssl documentation is a tad on the weak side in certain areas, profiling has revealed that using the: unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len, const unsigned char *d, int n, unsigned char *md, unsigned int *md_len); From here, shows 40% of my library runtime is devoted to creating and taking down **HMAC_CTX's behind the scenes. There are also two additional function to create and destroy a HMAC_CTX explicetly: HMAC_CTX_init() initialises a HMAC_CTX before first use. It must be called. HMAC_CTX_cleanup() erases the key and other data from the HMAC_CTX and releases any associated resources. It must be called when an HMAC_CTX is no longer required. These two function calls are prefixed with: The following functions may be used if the message is not completely stored in memory My data fits entirely in memory, so I choose the HMAC function -- the one whose signature is shown above. The context, as described by the man page, is made use of by using the following two functions: HMAC_Update() can be called repeatedly with chunks of the message to be authenticated (len bytes at data). HMAC_Final() places the message authentication code in md, which must have space for the hash function output. The Scope of the Application My application generates a authentic (HMAC, which is also used a nonce), CBC-BF encrypted protocol buffer string. The code will be interfaced with various web-servers and frameworks Windows / Linux as OS, nginx, Apache and IIS as webservers and Python / .NET and C++ web-server filters. The description above should clarify that the library needs to be thread safe, and potentially have resumeable processing state -- i.e., lightweight threads sharing a OS thread (which might leave thread local memory out of the picture). The Question How do I get rid of the 40% overhead on each invocation in a (1) thread-safe / (2) resume-able state way ? (2) is optional since I have all of the source-data present in one go, and can make sure a digest is created in place without relinquishing control of the thread mid-digest-creation. So, (1) can probably be done using thread local memory -- but how do I resuse the CTX's ? does the HMAC_final() call make the CTX reusable ?. (2) optional: in this case I would have to create a pool of CTX's. (3) how does the HMAC function do this ? does it create a CTX in the scope of the function call and destroy it ? Psuedocode and commentary will be useful.

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  • SQL group results as a column array

    - by Radek
    Hi guys, this is an SQL question and don't know which type of JOIN, GROUP BY etc. to use, it is for a chat program where messages are related to rooms and each day in a room is linked to a transcript etc. Basically, when outputting my transcripts, I need to show which users have chatted on that transcript. At the moment I link them through the messages like so: SELECT rooms.id, rooms.name, niceDate, room_transcripts.date, long FROM room_transcripts JOIN rooms ON room_transcripts.room=rooms.id JOIN transcript_users ON transcript_users.room=rooms.id AND transcript_users.date=room_transcripts.date JOIN users ON transcript_users.user=users.id WHERE room_transcripts.deleted=0 AND rooms.id IN (1,2) ORDER BY room_transcripts.id DESC, long ASC The result set looks like this: Array ( [0] => Array ( [id] => 2 [name] => Room 2 [niceDate] => Wednesday, April 14 [date] => 2010-04-14 [long] => Jerry Seinfeld ) [1] => Array ( [id] => 1 [name] => Room 1 [niceDate] => Wednesday, April 14 [date] => 2010-04-14 [long] => Jerry Seinfeld ) [2] => Array ( [id] => 1 [name] => Room 1 [niceDate] => Wednesday, April 14 [date] => 2010-04-14 [long] => Test Users ) ) I would like though for each element in the array to represent one transcript entry and for the users to be grouped in an array as the entry's element. So 'long' will be an array listing all the names. Can this be done? At the moment I just append the names and when the transcript date and room changes I echo them retrospectively, but I will do the same for files and highlighted messages and it's messy. Thanks.

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