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  • How do you control what your C compiler Optimizes?

    - by Jordan S
    I am writing the firmware for an embedded device in C using the Silicon Labs IDE and the SDCC compiler. The device architecture is based on the 8051 family. The function in question is shown below. The function is used to set the ports on my MCU to drive a stepper motor. It gets called in by an interrupt handler. The big switch statement just sets the ports to the proper value for the next motor step. The bottom part of the function looks at an input from a hall effect sensor and a number of steps moved in order to detect if the motor has stalled. The problem is, for some reason the second IF statement that looks like this if (StallDetector > (GapSize + 20)) { HandleStallEvent(); } always seems to get optimized out. If I try to put a breakpoint at the HandleStallEvent() call the IDE gives me a message saying "No Address Correlation to this line number". I am not really good enough at reading assembly to tell what it is doing but I have pasted a snippet from the asm output below. Any help would be much appreciated. void OperateStepper(void) { //static bit LastHomeMagState = HomeSensor; static bit LastPosMagState = PosSensor; if(PulseMotor) { if(MoveDirection == 1) // Go clockwise { switch(STEPPER_POSITION) { case 'A': STEPPER_POSITION = 'B'; P1 = 0xFD; break; case 'B': STEPPER_POSITION = 'C'; P1 = 0xFF; break; case 'C': STEPPER_POSITION = 'D'; P1 = 0xFE; break; case 'D': STEPPER_POSITION = 'A'; P1 = 0xFC; break; default: STEPPER_POSITION = 'A'; P1 = 0xFC; } //end switch } else // Go CounterClockwise { switch(STEPPER_POSITION) { case 'A': STEPPER_POSITION = 'D'; P1 = 0xFE; break; case 'B': STEPPER_POSITION = 'A'; P1 = 0xFC; break; case 'C': STEPPER_POSITION = 'B'; P1 = 0xFD; break; case 'D': STEPPER_POSITION = 'C'; P1 = 0xFF; break; default: STEPPER_POSITION = 'A'; P1 = 0xFE; } //end switch } //end else MotorSteps++; StallDetector++; if(PosSensor != LastPosMagState) { StallDetector = 0; LastPosMagState = PosSensor; } else { if (PosSensor == ON) { if (StallDetector > (MagnetSize + 20)) { HandleStallEvent(); } } else if (PosSensor == OFF) { if (StallDetector > (GapSize + 20)) { HandleStallEvent(); } } } } //end if PulseMotor } ... and the asm output for the the bottom part of this function... ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:653: if(PosSensor != LastPosMagState) mov c,_P1_4 jb _OperateStepper_LastPosMagState_1_1,00158$ cpl c 00158$: jc 00126$ C$MotionControl.c$655$3$7 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:655: StallDetector = 0; clr a mov _StallDetector,a mov (_StallDetector + 1),a C$MotionControl.c$657$3$7 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:657: LastPosMagState = PosSensor; mov c,_P1_4 mov _OperateStepper_LastPosMagState_1_1,c ret 00126$: C$MotionControl.c$661$2$8 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:661: if (PosSensor == ON) jb _P1_4,00123$ C$MotionControl.c$663$4$9 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:663: if (StallDetector > (MagnetSize + 20)) mov a,_MagnetSize mov r2,a rlc a subb a,acc mov r3,a mov a,#0x14 add a,r2 mov r2,a clr a addc a,r3 mov r3,a clr c mov a,r2 subb a,_StallDetector mov a,r3 subb a,(_StallDetector + 1) jnc 00130$ C$MotionControl.c$665$5$10 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:665: HandleStallEvent(); ljmp _HandleStallEvent 00123$: C$MotionControl.c$668$2$8 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:668: else if (PosSensor == OFF) jnb _P1_4,00130$ C$MotionControl.c$670$4$11 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:670: if (StallDetector > (GapSize + 20)) mov a,#0x14 add a,_GapSize mov r2,a clr a addc a,(_GapSize + 1) mov r3,a clr c mov a,r2 subb a,_StallDetector mov a,r3 subb a,(_StallDetector + 1) jnc 00130$ C$MotionControl.c$672$5$12 ==. ; C:\SiLabs\Optec Programs\HSFW_HID_SDCC_2\MotionControl.c:672: HandleStallEvent(); C$MotionControl.c$678$2$1 ==. XG$OperateStepper$0$0 ==. ljmp _HandleStallEvent 00130$: ret It looks to me like the compiler is NOT optimizing out this second if statement from the looks of the asm but if that is the case why does the IDE not allow me so set a breakpoint there? Maybe it's just a dumb IDE!

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  • Watching a variable for changes without polling.

    - by milkfilk
    I'm using a framework called Processing which is basically a Java applet. It has the ability to do key events because Applet can. You can also roll your own callbacks of sorts into the parent. I'm not doing that right now and maybe that's the solution. For now, I'm looking for a more POJO solution. So I wrote some examples to illustrate my question. Please ignore using key events on the command line (console). Certainly this would be a very clean solution but it's not possible on the command line and my actual app isn't a command line app. In fact, a key event would be a good solution for me but I'm trying to understand events and polling beyond just keyboard specific problems. Both these examples flip a boolean. When the boolean flips, I want to fire something once. I could wrap the boolean in an Object so if the Object changes, I could fire an event too. I just don't want to poll with an if() statement unnecessarily. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* * Example of checking a variable for changes. * Uses dumb if() and polls continuously. */ public class NotAvoidingPolling { public static void main(String[] args) { boolean typedA = false; String input = ""; System.out.println("Type 'a' please."); while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic if (input.equals("a")) { typedA = true; } else { typedA = false; } // problem: this is polling. if (typedA) System.out.println("Typed 'a'."); } } } Running this outputs: Type 'a' please. a Typed 'a'. On some forums people suggested using an Observer. And although this decouples the event handler from class being observed, I still have an if() on a forever loop. import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Observable; import java.util.Observer; /* * Example of checking a variable for changes. * This uses an observer to decouple the handler feedback * out of the main() but still is polling. */ public class ObserverStillPolling { boolean typedA = false; public static void main(String[] args) { // this ObserverStillPolling o = new ObserverStillPolling(); final MyEvent myEvent = new MyEvent(o); final MyHandler myHandler = new MyHandler(); myEvent.addObserver(myHandler); // subscribe // watch for event forever Thread thread = new Thread(myEvent); thread.start(); System.out.println("Type 'a' please."); String input = ""; while (true) { InputStreamReader isr = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(isr); try { input = br.readLine(); } catch (IOException ioException) { System.out.println("IO Error."); System.exit(1); } // contrived state change logic // but it's decoupled now because there's no handler here. if (input.equals("a")) { o.typedA = true; } } } } class MyEvent extends Observable implements Runnable { // boolean typedA; ObserverStillPolling o; public MyEvent(ObserverStillPolling o) { this.o = o; } public void run() { // watch the main forever while (true) { // event fire if (this.o.typedA) { setChanged(); // in reality, you'd pass something more useful notifyObservers("You just typed 'a'."); // reset this.o.typedA = false; } } } } class MyHandler implements Observer { public void update(Observable obj, Object arg) { // handle event if (arg instanceof String) { System.out.println("We received:" + (String) arg); } } } Running this outputs: Type 'a' please. a We received:You just typed 'a'. I'd be ok if the if() was a NOOP on the CPU. But it's really comparing every pass. I see real CPU load. This is as bad as polling. I can maybe throttle it back with a sleep or compare the elapsed time since last update but this is not event driven. It's just less polling. So how can I do this smarter? How can I watch a POJO for changes without polling? In C# there seems to be something interesting called properties. I'm not a C# guy so maybe this isn't as magical as I think. private void SendPropertyChanging(string property) { if (this.PropertyChanging != null) { this.PropertyChanging(this, new PropertyChangingEventArgs(property)); } }

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  • How should I change my Graph structure (very slow insertion)?

    - by Nazgulled
    Hi, This program I'm doing is about a social network, which means there are users and their profiles. The profiles structure is UserProfile. Now, there are various possible Graph implementations and I don't think I'm using the best one. I have a Graph structure and inside, there's a pointer to a linked list of type Vertex. Each Vertex element has a value, a pointer to the next Vertex and a pointer to a linked list of type Edge. Each Edge element has a value (so I can define weights and whatever it's needed), a pointer to the next Edge and a pointer to the Vertex owner. I have a 2 sample files with data to process (in CSV style) and insert into the Graph. The first one is the user data (one user per line); the second one is the user relations (for the graph). The first file is quickly inserted into the graph cause I always insert at the head and there's like ~18000 users. The second file takes ages but I still insert the edges at the head. The file has about ~520000 lines of user relations and takes between 13-15mins to insert into the Graph. I made a quick test and reading the data is pretty quickly, instantaneously really. The problem is in the insertion. This problem exists because I have a Graph implemented with linked lists for the vertices. Every time I need to insert a relation, I need to lookup for 2 vertices, so I can link them together. This is the problem... Doing this for ~520000 relations, takes a while. How should I solve this? Solution 1) Some people recommended me to implement the Graph (the vertices part) as an array instead of a linked list. This way I have direct access to every vertex and the insertion is probably going to drop considerably. But, I don't like the idea of allocating an array with [18000] elements. How practically is this? My sample data has ~18000, but what if I need much less or much more? The linked list approach has that flexibility, I can have whatever size I want as long as there's memory for it. But the array doesn't, how am I going to handle such situation? What are your suggestions? Using linked lists is good for space complexity but bad for time complexity. And using an array is good for time complexity but bad for space complexity. Any thoughts about this solution? Solution 2) This project also demands that I have some sort of data structures that allows quick lookup based on a name index and an ID index. For this I decided to use Hash Tables. My tables are implemented with separate chaining as collision resolution and when a load factor of 0.70 is reach, I normally recreate the table. I base the next table size on this http://planetmath.org/encyclopedia/GoodHashTablePrimes.html. Currently, both Hash Tables hold a pointer to the UserProfile instead of duplication the user profile itself. That would be stupid, changing data would require 3 changes and it's really dumb to do it that way. So I just save the pointer to the UserProfile. The same user profile pointer is also saved as value in each Graph Vertex. So, I have 3 data structures, one Graph and two Hash Tables and every single one of them point to the same exact UserProfile. The Graph structure will serve the purpose of finding the shortest path and stuff like that while the Hash Tables serve as quick index by name and ID. What I'm thinking to solve my Graph problem is to, instead of having the Hash Tables value point to the UserProfile, I point it to the corresponding Vertex. It's still a pointer, no more and no less space is used, I just change what I point to. Like this, I can easily and quickly lookup for each Vertex I need and link them together. This will insert the ~520000 relations pretty quickly. I thought of this solution because I already have the Hash Tables and I need to have them, then, why not take advantage of them for indexing the Graph vertices instead of the user profile? It's basically the same thing, I can still access the UserProfile pretty quickly, just go to the Vertex and then to the UserProfile. But, do you see any cons on this second solution against the first one? Or only pros that overpower the pros and cons on the first solution? Other Solution) If you have any other solution, I'm all ears. But please explain the pros and cons of that solution over the previous 2. I really don't have much time to be wasting with this right now, I need to move on with this project, so, if I'm doing to do such a change, I need to understand exactly what to change and if that's really the way to go. Hopefully no one fell asleep reading this and closed the browser, sorry for the big testament. But I really need to decide what to do about this and I really need to make a change. P.S: When answering my proposed solutions, please enumerate them as I did so I know exactly what are you talking about and don't confuse my self more than I already am.

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  • Help needed on an SQL configuration problem.

    - by user321048
    I have been banging my head with this one more the two weeks, and still don't know what the problem is ( I can't narrow it down). The problem is the following. I have a solution with 3 project in it all written in c# and I with LINQ. One project is the main web site, the other is the data layer (communication with the database) and the third one is a custom little CMS. The problem is the following: On a hosting provider when I publish the site it all works perfectly, but this site was needed to be hosted on the client server so I needed to do that. But the problem is that I also needed to configure the client server, because they don't have an Administrator employed (I know, I know ;) ). For the first time I some how managed, to set it up but a problem appear. My main web site is working just as it suppose to be - it reads (communicates with) the database, but My CMS is not. It shows the first log in page, but after that when I try to log in it throws the following error: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.) Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.) Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)] System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +4846887 System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +194 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) +4860189 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +90 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +342 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +221 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +189 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +185 System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +31 System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +433 System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +66 System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +499 System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +65 System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +117 System.Data.SqlClient.SqlConnection.Open() +122 System.Data.Linq.SqlClient.SqlConnectionManager.UseConnection(IConnectionUser user) +44 System.Data.Linq.SqlClient.SqlProvider.get_IsSqlCe() +45 System.Data.Linq.SqlClient.SqlProvider.InitializeProviderMode() +20 System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +57 System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute(Expression expression) +23 System.Linq.Queryable.Count(IQueryable`1 source) +240 CMS.Security.UserProfile.LoginUser() in C:\Documents and Settings\Dimitar\Desktop\New Mepso Final 08_04\CMS\Classes\UserProfile.cs:132 CMS.Default.Login1_Authenticate(Object sender, AuthenticateEventArgs e) in C:\Documents and Settings\Dimitar\Desktop\New Mepso Final 08_04\CMS\Default.aspx.cs:37 System.Web.UI.WebControls.Login.OnAuthenticate(AuthenticateEventArgs e) +108 System.Web.UI.WebControls.Login.AttemptLogin() +115 System.Web.UI.WebControls.Login.OnBubbleEvent(Object source, EventArgs e) +101 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +37 System.Web.UI.WebControls.Button.OnCommand(CommandEventArgs e) +118 System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +166 System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10 System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13 System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1565 Maybe this is a dumb question, but I cannot find the root of the problem, let alone the solution. So far I have tried the following: -setting time out on connection string to a higher value -configuration and after that turning off server firewall -checking the connection string over and over again (they are the same for all three projects and are saved in web.config) Important notes: I have tried executing the project from VS2008 with a connection string to the same database and the results are the same. That's why I think the problem is the SQL Server 2005 and not the IIS7. Any bit of information is more then welcomed.

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  • Fetch a specific tag from Rally in order to compute a value in another field

    - by 4jas
    I'm extremely new to Rally development so my question may sound dumb (but couldn't find how to do it from rally's help or from previous posts here) :) I've started from the rally freeform grid example - my purpose is to implement a Business Value calculator: I fill the score field with a 5-digit figure where each number is a score in the 1-5 range. Then I compute a business value as the result of a calculation, where each number is weighted by a preset weight. I can sort my stories by Business Value to help me prioritize my backlog: that's the first step, and it works. Now what I want to do is to make my freeform grid editable: I am extracting each of my digits as a separate column, but those columns are display-only. How can I turn them into something editable? What I want to do of course is update back the score field based on the values input in each custom column. Here's an example: I have a record with score "15254", which means Business Value criteria 1 scores 1 out of 5, Business Value criteria 2 scores 5 out of 5, and so on... In the end my Business Value is computed as "1*1 + 5*2 + 2*3 + 5*4 + 4*5 = 57". So far this is the part that works. Now let's say I found that the third criteria should not score 2 but 3, I want to be able to edit the value in the corresponding column and have my score field updated to "15354", and my Business Value to display 60 instead of 57. Here is my current code, I'll be really grateful if you can help me with turning that grid into something editable :) <!--Include SDK--> <script type="text/javascript" src="https://rally1.rallydev.com/apps/2.0p2/sdk-debug.js"></script> <!--App code--> <script type="text/javascript"> Rally.onReady(function() { Ext.define('BVApp', { extend: 'Rally.app.App', componentCls: 'app', launch: function() { Ext.create('Rally.data.WsapiDataStore', { model: 'UserStory', autoLoad: true, listeners: { load: this._onDataLoaded, scope: this } }); }, _onDataLoaded: function(store, data) { var records = []; var li_score; var li_bv1, li_bv2, li_bv3, li_bv4, li_bv5, li_bvtotal; var weights = new Array(1, 2, 3, 4, 5); Ext.Array.each(data, function(record) { //Let's fetch score and compute the business values... li_score = record.get('Score'); if (li_score) { li_bv1 = li_score.toString().substring(0,1); li_bv2 = li_score.toString().substring(1,2); li_bv3 = li_score.toString().substring(2,3); li_bv4 = li_score.toString().substring(3,4); li_bv5 = li_score.toString().substring(4,5); li_bvtotal = li_bv1*weights[0] + li_bv2*weights[1] + li_bv3*weights[2] + li_bv4*weights[3] + li_bv5*weights[4]; } records.push({ FormattedID: record.get('FormattedID'), ref: record.get('_ref'), Name: record.get('Name'), Score: record.get('Score'), Bv1: li_bv1, Bv2: li_bv2, Bv3: li_bv3, Bv4: li_bv4, Bv5: li_bv5, BvTotal: li_bvtotal }); }); this.add({ xtype: 'rallygrid', store: Ext.create('Rally.data.custom.Store', { data: records, pageSize: 5 }), columnCfgs: [ { text: 'FormattedID', dataIndex: 'FormattedID' }, { text: 'ref', dataIndex: 'ref' }, { text: 'Name', dataIndex: 'Name', flex: 1 }, { text: 'Score', dataIndex: 'Score' }, { text: 'BusVal 1', dataIndex: 'Bv1' }, { text: 'BusVal 2', dataIndex: 'Bv2' }, { text: 'BusVal 3', dataIndex: 'Bv3' }, { text: 'BusVal 4', dataIndex: 'Bv4' }, { text: 'BusVal 5', dataIndex: 'Bv5' }, { text: 'BusVal Total', dataIndex: 'BvTotal' } ] }); } }); Rally.launchApp('BVApp', { name: 'Business Values App' }); var exampleHtml = '<div id="example-intro"><h1>Business Values App</h1>' + '<div>Own sample app for Business Values</div>' + '</div>'; // Default app viewport uses layout: 'fit', // so we need to insert a container into the viewport var viewport = Ext.ComponentQuery.query('viewport')[0]; var appComponent = viewport.items.getAt(0); var viewportContainerItems = [{ html: exampleHtml, border: 0 }]; //hide advanced cardboard live previews in examples for now viewportContainerItems.push({ xtype: 'container', items: [appComponent] }); viewport.remove(appComponent, false); viewport.add({ xtype: 'container', layout: 'vbox', items: viewportContainerItems }); }); </script> <!--App styles--> <style type="text/css"> .app { /* Add app styles here */ } </style>

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  • Multiset of shared_ptrs as a dynamic priority queue: Concept and practice

    - by Sarah
    I was using a vector-based priority queue typedef std::priority_queue< Event, vector< Event >, std::greater< Event > > EventPQ; to manage my Event objects. Now my simulation has to be able to find and delete certain Event objects not at the top of the queue. I'd like to know if my planned work-around can do what I need it to, and if I have the syntax right. I'd also like to know if dramatically better solutions exist. My plan is to make EventPQ a multiset of smart pointers to Event objects: typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; I'm borrowing functions of the Event class from a related post on a multimap priority queue. // Event.h #include <cstdlib> using namespace std; #include <set> #include <boost/shared_ptr.hpp> class Event; typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; class Event { public: Event( double t, int eid, int hid ); ~Event(); void add( EventPQ& q ); void remove(); bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } bool operator > ( const Event & rhs ) const { return ( time > rhs.time ); } double time; int eventID; int hostID; EventPQ* mq; EventPQ::iterator mIt; }; // Event.cpp Event::Event( double t, int eid, int hid ) { time = t; eventID = eid; hostID = hid; } Event::~Event() {} void Event::add( EventPQ& q ) { mq = &q; mIt = q.insert( boost::shared_ptr<Event>(this) ); } void Event::remove() { mq.erase( mIt ); mq = 0; mIt = EventPQ::iterator(); } I was hoping that by making EventPQ a container of pointers, I could avoid wasting time copying Events into the container and avoid accidentally editing the wrong copy. Would it be dramatically easier to store the Events themselves in EventPQ instead? Does it make more sense to remove the time keys from Event objects and use them instead as keys in a multimap? Assuming the current implementation seems okay, my questions are: Do I need to specify how to sort on the pointers, rather than the objects, or does the multiset automatically know to sort on the objects pointed to? If I have a shared_ptr ptr1 to an Event that also has a pointer in the EventPQ container, how do I find and delete the corresponding pointer in EventPQ? Is it enough to .find( ptr1 ), or do I instead have to find by the key (time)? Is the Event::remove() sufficient for removing the pointer in the EventPQ container? There's a small chance multiple events could be created with the same time (obviously implied in the use of multiset). If the find() works on event times, to avoid accidentally deleting the wrong event, I was planning to throw in a further check on eventID and hostID. Does this seem reasonable? (Dumb syntax question) In Event.h, is the declaration of dummy class Event;, then the EventPQ typedef, and then the real class Event declaration appropriate? I'm obviously an inexperienced programmer with very spotty background--this isn't for homework. Would love suggestions and explanations. Please let me know if any part of this is confusing. Thanks.

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  • Find the set of largest contiguous rectangles to cover multiple areas

    - by joelpt
    I'm working on a tool called Quickfort for the game Dwarf Fortress. Quickfort turns spreadsheets in csv/xls format into a series of commands for Dwarf Fortress to carry out in order to plot a "blueprint" within the game. I am currently trying to optimally solve an area-plotting problem for the 2.0 release of this tool. Consider the following "blueprint" which defines plotting commands for a 2-dimensional grid. Each cell in the grid should either be dug out ("d"), channeled ("c"), or left unplotted ("."). Any number of distinct plotting commands might be present in actual usage. . d . d c c d d d d c c . d d d . c d d d d d c . d . d d c To minimize the number of instructions that need to be sent to Dwarf Fortress, I would like to find the set of largest contiguous rectangles that can be formed to completely cover, or "plot", all of the plottable cells. To be valid, all of a given rectangle's cells must contain the same command. This is a faster approach than Quickfort 1.0 took: plotting every cell individually as a 1x1 rectangle. This video shows the performance difference between the two versions. For the above blueprint, the solution looks like this: . 9 . 0 3 2 8 1 1 1 3 2 . 1 1 1 . 2 7 1 1 1 4 2 . 6 . 5 4 2 Each same-numbered rectangle above denotes a contiguous rectangle. The largest rectangles take precedence over smaller rectangles that could also be formed in their areas. The order of the numbering/rectangles is unimportant. My current approach is iterative. In each iteration, I build a list of the largest rectangles that could be formed from each of the grid's plottable cells by extending in all 4 directions from the cell. After sorting the list largest first, I begin with the largest rectangle found, mark its underlying cells as "plotted", and record the rectangle in a list. Before plotting each rectangle, its underlying cells are checked to ensure they are not yet plotted (overlapping a previous plot). We then start again, finding the largest remaining rectangles that can be formed and plotting them until all cells have been plotted as part of some rectangle. I consider this approach slightly more optimized than a dumb brute-force search, but I am wasting a lot of cycles (re)calculating cells' largest rectangles and checking underlying cells' states. Currently, this rectangle-discovery routine takes the lion's share of the total runtime of the tool, especially for large blueprints. I have sacrificed some accuracy for the sake of speed by only considering rectangles from cells which appear to form a rectangle's corner (determined using some neighboring-cell heuristics which aren't always correct). As a result of this 'optimization', my current code doesn't actually generate the above solution correctly, but it's close enough. More broadly, I consider the goal of largest-rectangles-first to be a "good enough" approach for this application. However I observe that if the goal is instead to find the minimum set (fewest number) of rectangles to completely cover multiple areas, the solution would look like this instead: . 3 . 5 6 8 1 3 4 5 6 8 . 3 4 5 . 8 2 3 4 5 7 8 . 3 . 5 7 8 This second goal actually represents a more optimal solution to the problem, as fewer rectangles usually means fewer commands sent to Dwarf Fortress. However, this approach strikes me as closer to NP-Hard, based on my limited math knowledge. Watch the video if you'd like to better understand the overall strategy; I have not addressed other aspects of Quickfort's process, such as finding the shortest cursor-path that plots all rectangles. Possibly there is a solution to this problem that coherently combines these multiple strategies. Help of any form would be appreciated.

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  • How to shoot yourself in the foot (DO NOT Read in the office)

    - by TATWORTH
    Originally posted on: http://geekswithblogs.net/TATWORTH/archive/2013/06/21/how-to-shoot-yourself-in-the-foot-do-not-read.aspxLet me make it absolutely clear - the following is:merely collated by your Geek from http://www.codeproject.com/Lounge.aspx?msg=3917012#xx3917012xxvery, very very funny so you read it in the presence of others at your own riskso here is the list - you have been warned!C You shoot yourself in the foot.   C++ You accidently create a dozen instances of yourself and shoot them all in the foot. Providing emergency medical assistance is impossible since you can't tell which are bitwise copies and which are just pointing at others and saying "That's me, over there."   FORTRAN You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you have no exception-handling facility.   Modula-2 After realizing that you can't actually accomplish anything in this language, you shoot yourself in the head.   COBOL USEing a COLT 45 HANDGUN, AIM gun at LEG.FOOT, THEN place ARM.HAND.FINGER on HANDGUN.TRIGGER and SQUEEZE. THEN return HANDGUN to HOLSTER. CHECK whether shoelace needs to be retied.   Lisp You shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds the gun with which you shoot yourself in the appendage which holds...   BASIC Shoot yourself in the foot with a water pistol. On big systems, continue until entire lower body is waterlogged.   Forth Foot yourself in the shoot.   APL You shoot yourself in the foot; then spend all day figuring out how to do it in fewer characters.   Pascal The compiler won't let you shoot yourself in the foot.   Snobol If you succeed, shoot yourself in the left foot. If you fail, shoot yourself in the right foot.   HyperTalk Put the first bullet of the gun into foot left of leg of you. Answer the result.   Prolog You tell your program you want to be shot in the foot. The program figures out how to do it, but the syntax doesn't allow it to explain.   370 JCL You send your foot down to MIS with a 4000-page document explaining how you want it to be shot. Three years later, your foot comes back deep-fried.   FORTRAN-77 You shoot yourself in each toe, iteratively, until you run out of toes, then you read in the next foot and repeat. If you run out of bullets, you continue anyway because you still can't do exception-processing.   Modula-2 (alternative) You perform a shooting on what might be currently a foot with what might be currently a bullet shot by what might currently be a gun.   BASIC (compiled) You shoot yourself in the foot with a BB using a SCUD missile launcher.   Visual Basic You'll really only appear to have shot yourself in the foot, but you'll have so much fun doing it that you won't care.   Forth (alternative) BULLET DUP3 * GUN LOAD FOOT AIM TRIGGER PULL BANG! EMIT DEAD IF DROP ROT THEN (This takes about five bytes of memory, executes in two to ten clock cycles on any processor and can be used to replace any existing function of the language as well as in any future words). (Welcome to bottom up programming - where you, too, can perform compiler pre-processing instead of writing code)   APL (alternative) You hear a gunshot and there's a hole in your foot, but you don't remember enough linear algebra to understand what happened. or @#&^$%&%^ foot   Pascal (alternative) Same as Modula-2 except that the bullet is not the right type for the gun and your hand is blown off.   Snobol (alternative) You grab your foot with your hand, then rewrite your hand to be a bullet. The act of shooting the original foot then changes your hand/bullet into yet another foot (a left foot).   Prolog (alternative) You attempt to shoot yourself in the foot, but the bullet, failing to find its mark, backtracks to the gun, which then explodes in your face.   COMAL You attempt to shoot yourself in the foot with a water pistol, but the bore is clogged, and the pressure build-up blows apart both the pistol and your hand. or draw_pistol aim_at_foot(left) pull_trigger hop(swearing)   Scheme As Lisp, but none of the other appendages are aware of this happening.   Algol You shoot yourself in the foot with a musket. The musket is aesthetically fascinating and the wound baffles the adolescent medic in the emergency room.   Ada If you are dumb enough to actually use this language, the United States Department of Defense will kidnap you, stand you up in front of a firing squad and tell the soldiers, "Shoot at the feet." or The Department of Defense shoots you in the foot after offering you a blindfold and a last cigarette. or After correctly packaging your foot, you attempt to concurrently load the gun, pull the trigger, scream and shoot yourself in the foot. When you try, however, you discover that your foot is of the wrong type. or After correctly packing your foot, you attempt to concurrently load the gun, pull the trigger, scream, and confidently aim at your foot knowing it is safe. However the cordite in the round does an Unchecked Conversion, fires and shoots you in the foot anyway.   Eiffel   You create a GUN object, two FOOT objects and a BULLET object. The GUN passes both the FOOT objects a reference to the BULLET. The FOOT objects increment their hole counts and forget about the BULLET. A little demon then drives a garbage truck over your feet and grabs the bullet (both of it) on the way. Smalltalk You spend so much time playing with the graphics and windowing system that your boss shoots you in the foot, takes away your workstation and makes you develop in COBOL on a character terminal. or You send the message shoot to gun, with selectors bullet and myFoot. A window pops up saying Gunpowder doesNotUnderstand: spark. After several fruitless hours spent browsing the methods for Trigger, FiringPin and IdealGas, you take the easy way out and create ShotFoot, a subclass of Foot with an additional instance variable bulletHole. Object Oriented Pascal You perform a shooting on what might currently be a foot with what might currently be a bullet fired from what might currently be a gun.   PL/I You consume all available system resources, including all the offline bullets. The Data Processing & Payroll Department doubles its size, triples its budget, acquires four new mainframes and drops the original one on your foot. Postscript foot bullets 6 locate loadgun aim gun shoot showpage or It takes the bullet ten minutes to travel from the gun to your foot, by which time you're long since gone out to lunch. The text comes out great, though.   PERL You stab yourself in the foot repeatedly with an incredibly large and very heavy Swiss Army knife. or You pick up the gun and begin to load it. The gun and your foot begin to grow to huge proportions and the world around you slows down, until the gun fires. It makes a tiny hole, which you don't feel. Assembly Language You crash the OS and overwrite the root disk. The system administrator arrives and shoots you in the foot. After a moment of contemplation, the administrator shoots himself in the foot and then hops around the room rabidly shooting at everyone in sight. or You try to shoot yourself in the foot only to discover you must first reinvent the gun, the bullet, and your foot.or The bullet travels to your foot instantly, but it took you three weeks to load the round and aim the gun.   BCPL You shoot yourself somewhere in the leg -- you can't get any finer resolution than that. Concurrent Euclid You shoot yourself in somebody else's foot.   Motif You spend days writing a UIL description of your foot, the trajectory, the bullet and the intricate scrollwork on the ivory handles of the gun. When you finally get around to pulling the trigger, the gun jams.   Powerbuilder While attempting to load the gun you discover that the LoadGun system function is buggy; as a work around you tape the bullet to the outside of the gun and unsuccessfully attempt to fire it with a nail. In frustration you club your foot with the butt of the gun and explain to your client that this approximates the functionality of shooting yourself in the foot and that the next version of Powerbuilder will fix it.   Standard ML By the time you get your code to typecheck, you're using a shoot to foot yourself in the gun.   MUMPS You shoot 583149 AK-47 teflon-tipped, hollow-point, armour-piercing bullets into even-numbered toes on odd-numbered feet of everyone in the building -- with one line of code. Three weeks later you shoot yourself in the head rather than try to modify that line.   Java You locate the Gun class, but discover that the Bullet class is abstract, so you extend it and write the missing part of the implementation. Then you implement the ShootAble interface for your foot, and recompile the Foot class. The interface lets the bullet call the doDamage method on the Foot, so the Foot can damage itself in the most effective way. Now you run the program, and call the doShoot method on the instance of the Gun class. First the Gun creates an instance of Bullet, which calls the doFire method on the Gun. The Gun calls the hit(Bullet) method on the Foot, and the instance of Bullet is passed to the Foot. But this causes an IllegalHitByBullet exception to be thrown, and you die.   Unix You shoot yourself in the foot or % ls foot.c foot.h foot.o toe.c toe.o % rm * .o rm: .o: No such file or directory % ls %   370 JCL (alternative) You shoot yourself in the head just thinking about it.   DOS JCL You first find the building you're in in the phone book, then find your office number in the corporate phone book. Then you have to write this down, then describe, in cubits, your exact location, in relation to the door (right hand side thereof). Then you need to write down the location of the gun (loading it is a proprietary utility), then you load it, and the COBOL program, and run them, and, with luck, it may be run tonight.   VMS   $ MOUNT/DENSITY=.45/LABEL=BULLET/MESSAGE="BYE" BULLET::BULLET$GUN SYS$BULLET $ SET GUN/LOAD/SAFETY=OFF/SIGHT=NONE/HAND=LEFT/CHAMBER=1/ACTION=AUTOMATIC/ LOG/ALL/FULL SYS$GUN_3$DUA3:[000000]GUN.GNU $ SHOOT/LOG/AUTO SYS$GUN SYS$SYSTEM:[FOOT]FOOT.FOOT   %DCL-W-ACTIMAGE, error activating image GUN -CLI-E-IMGNAME, image file $3$DUA240:[GUN]GUN.EXE;1 -IMGACT-F-NOTNATIVE, image is not an OpenVMS Alpha AXP image or %SYS-F-FTSHT, foot shot (fifty lines of traceback omitted) sh,csh, etc You can't remember the syntax for anything, so you spend five hours reading manual pages, then your foot falls asleep. You shoot the computer and switch to C.   Apple System 7 Double click the gun icon and a window giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small bomb appears with note "Error of Type 1 has occurred."   Windows 3.1 Double click the gun icon and wait. Eventually a window opens giving a selection for guns, target areas, plus balloon help with medical remedies, and assorted sound effects. Click "shoot" button and a small box appears with note "Unable to open Shoot.dll, check that path is correct."   Windows 95 Your gun is not compatible with this OS and you must buy an upgrade and install it before you can continue. Then you will be informed that you don't have enough memory.   CP/M I remember when shooting yourself in the foot with a BB gun was a big deal.   DOS You finally found the gun, but can't locate the file with the foot for the life of you.   MSDOS You shoot yourself in the foot, but can unshoot yourself with add-on software.   Access You try to point the gun at your foot, but it shoots holes in all your Borland distribution diskettes instead.   Paradox Not only can you shoot yourself in the foot, your users can too.   dBase You squeeze the trigger, but the bullet moves so slowly that by the time your foot feels the pain, you've forgotten why you shot yourself anyway. or You buy a gun. Bullets are only available from another company and are promised to work so you buy them. Then you find out that the next version of the gun is the one scheduled to actually shoot bullets.   DBase IV, V1.0 You pull the trigger, but it turns out that the gun was a poorly designed hand grenade and the whole building blows up.   SQL You cut your foot off, send it out to a service bureau and when it returns, it has a hole in it but will no longer fit the attachment at the end of your leg. or Insert into Foot Select Bullet >From Gun.Hand Where Chamber = 'LOADED' And Trigger = 'PULLED'   Clipper You grab a bullet, get ready to insert it in the gun so that you can shoot yourself in the foot and discover that the gun that the bullets fits has not yet been built, but should be arriving in the mail _REAL_SOON_NOW_. Oracle The menus for coding foot_shooting have not been implemented yet and you can't do foot shooting in SQL.   English You put your foot in your mouth, then bite it off. (For those who don't know, English is a McDonnell Douglas/PICK query language which allegedly requires 110% of system resources to run happily.) Revelation [an implementation of the PICK Operating System] You'll be able to shoot yourself in the foot just as soon as you figure out what all these bullets are for.   FlagShip Starting at the top of your head, you aim the gun at yourself repeatedly until, half an hour later, the gun is finally pointing at your foot and you pull the trigger. A new foot with a hole in it appears but you can't work out how to get rid of the old one and your gun doesn't work anymore.   FidoNet You put your foot in your mouth, then echo it internationally.   PicoSpan [a UNIX-based computer conferencing system] You can't shoot yourself in the foot because you're not a host. or (host variation) Whenever you shoot yourself in the foot, someone opens a topic in policy about it.   Internet You put your foot in your mouth, shoot it, then spam the bullet so that everybody gets shot in the foot.   troff rmtroff -ms -Hdrwp | lpr -Pwp2 & .*place bullet in footer .B .NR FT +3i .in 4 .bu Shoot! .br .sp .in -4 .br .bp NR HD -2i .*   Genetic Algorithms You create 10,000 strings describing the best way to shoot yourself in the foot. By the time the program produces the optimal solution, humans have evolved wings and the problem is moot.   CSP (Communicating Sequential Processes) You only fail to shoot everything that isn't your foot.   MS-SQL Server MS-SQL Server’s gun comes pre-loaded with an unlimited supply of Teflon coated bullets, and it only has two discernible features: the muzzle and the trigger. If that wasn't enough, MS-SQL Server also puts the gun in your hand, applies local anesthetic to the skin of your forefinger and stitches it to the gun's trigger. Meanwhile, another process has set up a spinal block to numb your lower body. It will then proceeded to surgically remove your foot, cryogenically freeze it for preservation, and attach it to the muzzle of the gun so that no matter where you aim, you will shoot your foot. In order to avoid shooting yourself in the foot, you need to unstitch your trigger finger, remove your foot from the muzzle of the gun, and have it surgically reattached. Then you probably want to get some crutches and go out to buy a book on SQL Server Performance Tuning.   Sybase Sybase's gun requires assembly, and you need to go out and purchase your own clip and bullets to load the gun. Assembly is complicated by the fact that Sybase has hidden the gun behind a big stack of reference manuals, but it hasn't told you where that stack is. While you were off finding the gun, assembling it, buying bullets, etc., Sybase was also busy surgically removing your foot and cryogenically freezing it for preservation. Instead of attaching it to the muzzle of the gun, though, it packed your foot on dry ice and sent it UPS-Ground to an unnamed hookah bar somewhere in the middle east. In order to shoot your foot, you must modify your gun with a GPS system for targeting and hire some guy named "Indy" to find the hookah bar and wire the coordinates back to you. By this time, you've probably become so daunted at the tasks stand between you and shooting your foot that you hire a guy who's read all the books on Sybase to help you shoot your foot. If you're lucky, he'll be smart enough both to find your foot and to stop you from shooting it.   Magic software You spend 1 week looking up the correct syntax for GUN. When you find it, you realise that GUN will not let you shoot in your own foot. It will allow you to shoot almost anything but your foot. You then decide to build your own gun. You can't use the standard barrel since this will only allow for standard bullets, which will not fire if the barrel is pointed at your foot. After four weeks, you have created your own custom gun. It blows up in your hand without warning, because you failed to initialise the safety catch and it doesn't know whether the initial state is "0", 0, NULL, "ZERO", 0.0, 0,0, "0.0", or "0,00". You fix the problem with your remaining hand by nesting 12 safety catches, and then decide to build the gun without safety catch. You then shoot the management and retire to a happy life where you code in languages that will allow you to shoot your foot in under 10 days.FirefoxLets you shoot yourself in as many feet as you'd like, while using multiple great addons! IEA moving target in terms of standard ammunition size and doesn't always work properly with non-Microsoft ammunition, so sometimes you shoot something other than your foot. However, it's the corporate world's standard foot-shooting apparatus. Hackers seem to enjoy rigging websites up to trigger cascading foot-shooting failures. Windows 98 About the same as Windows 95 in terms of overall bullet capacity and triggering mechanisms. Includes updated DirectShot API. A new version was released later on to support USB guns, Windows 98 SE.WPF:You get your baseball glove and a ball and you head out to your backyard, where you throw balls to your pitchback. Then your unkempt-haired-cargo-shorts-and-sandals-with-white-socks-wearing neighbor uses XAML to sculpt your arm into a gun, the ball into a bullet and the pitchback into your foot. By now, however, only the neighbor can get it to work and he's only around from 6:30 PM - 3:30 AM. LOGO: You very carefully lay out the trajectory of the bullet. Then you start the gun, which fires very slowly. You walk precisely to the point where the bullet will travel and wait, but just before it gets to you, your class time is up and one of the other kids has already used the system to hack into Sony's PS3 network. Flash: Someone has designed a beautiful-looking gun that anyone can shoot their feet with for free. It weighs six hundred pounds. All kinds of people are shooting themselves in the feet, and sending the link to everyone else so that they can too. That is, except for the criminals, who are all stealing iOS devices that the gun won't work with.APL: Its (mostly) all greek to me. Lisp: Place ((gun in ((hand sight (foot then shoot))))) (Lots of Insipid Stupid Parentheses)Apple OS/X and iOS Once a year, Steve Jobs returns from sick leave to tell millions of unwavering fans how they will be able to shoot themselves in the foot differently this year. They retweet and blog about it ad nauseam, and wait in line to be the first to experience "shoot different".Windows ME Usually fails, even at shooting you in the foot. Yo dawg, I heard you like shooting yourself in the foot. So I put a gun in your gun, so you can shoot yourself in the foot while you shoot yourself in the foot. (Okay, I'm not especially proud of this joke.) Windows 2000 Now you really do have to log in, before you are allowed to shoot yourself in the foot.Windows XPYou thought you learned your lesson: Don't use Windows ME. Then, along came this new creature, built on top of Windows NT! So you spend the next couple days installing antivirus software, patches and service packs, just so you can get that driver to install, and then proceed to shoot yourself in the foot. Windows Vista Newer! Glossier! Shootier! Windows 7 The bullets come out a lot smoother. Active Directory Each bullet now has an attached Bullet Identifier, and can be uniquely identified. Policies can be applied to dictate fragmentation, and the gun will occasionally have a confusing delay after the trigger has been pulled. PythonYou try to use import foot; foot.shoot() only to realize that's only available in 3.0, to which you can't yet upgrade from 2.7 because of all those extension libs lacking support. Solaris Shoots best when used on SPARC hardware, but still runs the trigger GUI under Java. After weeks of learning the appropriate STOP command to prevent the trigger from automatically being pressed on boot, you think you've got it under control. Then the one time you ever use dtrace, it hits a bug that fires the gun. MySQL The feature that allows you to shoot yourself in the foot has been in development for about 6 years, and they are adding it into the next version, which is coming out REAL SOON NOW, promise! But you can always check it out of source control and try it yourself (just not in any environment where data integrity is important because it will probably explode.) PostgreSQLAllows you to have a smug look on your face while you shoot yourself in the foot, because those MySQL guys STILL don't have that feature. NoSQL Barrel? Who needs a barrel? Just put the bullet on your foot, and strike it with a hammer. See? It's so much simpler and more efficient that way. You can even strike multiple bullets in one swing if you swing with a good enough arc, because hammers are easy to use. Getting them to synchronize is a little difficult, though.Eclipse There are about a dozen different packages for shooting yourself in the foot, with weird interdependencies on outdated components. Once you finally navigate the morass and get one installed, you then have something to look at while you shoot yourself in the foot with that package: You can watch the screen redraw.Outlook Makes it really easy to let everyone know you shot yourself in the foot!Shooting yourself in the foot using delegates.You really need to shoot yourself in the foot but you hate firearms (you don't want any dependency on the specifics of shooting) so you delegate it to somebody else. You don't care how it is done as long is shooting your foot. You can do it asynchronously in case you know you may faint so you are called back/slapped in the face by your shooter/friend (or background worker) when everything is done.C#You prepare the gun and the bullet, carefully modeling all of the physics of a bullet traveling through a foot. Just before you're about to pull the trigger, you stumble on System.Windows.BodyParts.Foot.ShootAt(System.Windows.Firearms.IGun gun) in the extended framework, realize you just wasted the entire afternoon, and shoot yourself in the head.PHP<?phprequire("foot_safety_check.php");?><!DOCTYPE HTML><html><head> <!--Lower!--><title>Shooting me in the foot</title></head> <body> <!--LOWER!!!--><leg> <!--OK, I made this one up...--><footer><?php echo (dungSift($_SERVER['HTTP_USER_AGENT'], "ie"))?("Your foot is safe, but you might want to wear a hard hat!"):("<div class=\"shot\">BANG!</div>"); ?></footer></leg> </body> </html>

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  • Committed JDO writes do not apply on local GAE HRD, or possibly reused transaction

    - by eeeeaaii
    I'm using JDO 2.3 on app engine. I was using the Master/Slave datastore for local testing and recently switched over to using the HRD datastore for local testing, and parts of my app are breaking (which is to be expected). One part of the app that's breaking is where it sends a lot of writes quickly - that is because of the 1-second limit thing, it's failing with a concurrent modification exception. Okay, so that's also to be expected, so I have the browser retry the writes again later when they fail (maybe not the best hack but I'm just trying to get it working quickly). But a weird thing is happening. Some of the writes which should be succeeding (the ones that DON'T get the concurrent modification exception) are also failing, even though the commit phase completes and the request returns my success code. I can see from the log that the retried requests are working okay, but these other requests that seem to have committed on the first try are, I guess, never "applied." But from what I read about the Apply phase, writing again to that same entity should force the apply... but it doesn't. Code follows. Some things to note: I am attempting to use automatic JDO caching. So this is where JDO uses memcache under the covers. This doesn't actually work unless you wrap everything in a transaction. all the requests are doing is reading a string out of an entity, modifying part of the string, and saving that string back to the entity. If these requests weren't in transactions, you'd of course have the "dirty read" problem. But with transactions, isolation is supposed to be at the level of "serializable" so I don't see what's happening here. the entity being modified is a root entity (not in a group) I have cross-group transactions enabled Another weird thing is happening. If the concurrent modification thing happens, and I subsequently edit more than 5 more entities (this is the max for cross-group transactions), then nothing happens right away, but when I stop and restart the server I get "IllegalArgumentException: operating on too many entity groups in a single transaction". Could it be possible that the PMF is returning the same PersistenceManager every time, or the PM is reusing the same transaction every time? I don't see how I could possibly get the above error otherwise. The code inside the transaction just edits one root entity. I can't think of any other way that GAE would give me the "too many entity groups" error. The relevant code (this is a simplified version) PersistenceManager pm = PMF.getManager(); Transaction tx = pm.currentTransaction(); String responsetext = ""; try { tx.begin(); // I have extra calls to "makePersistent" because I found that relying // on pm.close didn't always write the objects to cache, maybe that // was only a DataNucleus 1.x issue though Key userkey = obtainUserKeyFromCookie(); User u = pm.getObjectById(User.class, userkey); pm.makePersistent(u); // to make sure it gets cached for next time Key mapkey = obtainMapKeyFromQueryString(); // this is NOT a java.util.Map, just FYI Map currentmap = pm.getObjectById(Map.class, mapkey); Text mapData = currentmap.getMapData(); // mapData is JSON stored in the entity Text newMapData = parseModifyAndReturn(mapData); // transform the map currentmap.setMapData(newMapData); // mutate the Map object pm.makePersistent(currentmap); // make sure to persist so there is a cache hit tx.commit(); responsetext = "OK"; } catch (JDOCanRetryException jdoe) { // log jdoe responsetext = "RETRY"; } catch (Exception e) { // log e responsetext = "ERROR"; } finally { if (tx.isActive()) { tx.rollback(); } pm.close(); } resp.getWriter().println(responsetext); EDIT: so I have verified that it fails after exactly 5 transactions. Here's what I do: I create a Foo (root entity), do a bunch of concurrent operations on that Foo, and some fail and get retried, and some commit but don't apply (as described above). Then, I start creating more Foos, and do a few operations on those new Foos. If I only create four Foos, stopping and restarting app engine does NOT give me the IllegalArgumentException. However if I create five Foos (which is the limit for cross-group transactions), then when I stop and restart app engine, I do get the exception. So it seems that somehow these new Foos I am creating are counting toward the limit of 5 max entities per transaction, even though they are supposed to be handled by separate transactions. It's as if a transaction is still open and is being reused by the servlet when it handles the new requests for the 2nd through 5th Foos. EDIT2: it looks like the IllegalArgument thing is independent of the other bug. In other words, it always happens when I create five Foos, even if I don't get the concurrent modification exception. I don't know if it's a symptom of the same problem or if it's unrelated. EDIT3: I found out what was causing the (unrelated) IllegalArgumentException, it was a dumb mistake on my part. But the other issue is still happening. EDIT4: added pseudocode for the datastore access EDIT5: I am pretty sure I know why this is happening, but I will still award the bounty to anyone who can confirm it. Basically, I think the problem is that transactions are not really implemented in the local version of the datastore. References: https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/gVMS1dFSpcU https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/deGasFdIO-M https://groups.google.com/forum/?hl=en&fromgroups=#!msg/google-appengine-java/4YuNb6TVD6I/gSttMmHYwo0J Because transactions are not implemented, rollback is essentially a no-op. Therefore, I get a dirty read when two transactions try to modify the record at the same time. In other words, A reads the data and B reads the data at the same time. A attempts to modify the data, and B attempts to modify a different part of the data. A writes to the datastore, then B writes, obliterating A's changes. Then B is "rolled back" by app engine, but since rollbacks are a no-op when running on the local datastore, B's changes stay, and A's do not. Meanwhile, since B is the thread that threw the exception, the client retries B, but does not retry A (since A was supposedly the transaction that succeeded).

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  • Problems with DNS propagation 10 days after a change was made

    - by runlevel6
    The engineering team I work with has been in the process of moving equipment from one datacenter to another. Ten days ago we moved one of our name servers authoritative for our client's domains (ns1.faithhiway.com) and updated its IP address with its respective DNS provider (register.com) to point to the new datacenter. All tests done show that this name server is correctly running at its new location and when queried, returning the correct response for any domains it is responsible for. The problem is that well after 72 hours had gone by we were still seeing more DNS activity at its old IP address than at the new. The good news is that we kept a name server responding on the old IP address for the time being so we are not seeing any issues with the domains our nameserver is responsible for but the goal is to retire that as soon as possible. As you can see from WhatsMyDNS.net, a decent amount of propagation has occurred over the last 10 days since we made this change, but still there are some locations reporting our original IP. Considering that the TTL is only 3600 with the name servers responsible for this domain, it does not make any sense to myself or the other engineers working with me that we are having this issue. Now if I run a DNS check using one of the Register.com DNS servers (direct nameservers for faithhiway.com), I get the following (correct) result: # dig @dns01.gpn.register.com ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @dns01.gpn.register.com. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43232 ;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 5 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 3601 IN A 206.127.2.71 ;; AUTHORITY SECTION: faithhiway.com. 3600 IN NS dns01.gpn.register.com. faithhiway.com. 3600 IN NS dns02.gpn.register.com. faithhiway.com. 3600 IN NS dns03.gpn.register.com. faithhiway.com. 3600 IN NS dns04.gpn.register.com. faithhiway.com. 3600 IN NS dns05.gpn.register.com. ;; ADDITIONAL SECTION: dns01.gpn.register.com. 3600 IN A 98.124.192.1 dns02.gpn.register.com. 3600 IN A 98.124.197.1 dns03.gpn.register.com. 3600 IN A 98.124.193.1 dns04.gpn.register.com. 3600 IN A 69.64.145.225 dns05.gpn.register.com. 3600 IN A 98.124.196.1 ;; Query time: 50 msec ;; SERVER: 98.124.192.1#53(98.124.192.1) ;; WHEN: Thu Jan 27 15:16:57 2011 ;; MSG SIZE rcvd: 269 Just as a reference, here are the results when the same query is checked against a variety of Public DNS servers: Google: # dig @8.8.8.8 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @8.8.8.8. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12773 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 997 IN A 206.127.2.71 ;; Query time: 29 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Thu Jan 27 15:17:31 2011 ;; MSG SIZE rcvd: 52 Level 3: # dig @4.2.2.1 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @4.2.2.1. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46505 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 2623 IN A 206.127.2.71 ;; Query time: 7 msec ;; SERVER: 4.2.2.1#53(4.2.2.1) ;; WHEN: Thu Jan 27 15:18:35 2011 ;; MSG SIZE rcvd: 52 Verizon: # dig @151.197.0.38 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @151.197.0.38. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32658 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 3601 IN A 206.127.2.71 ;; Query time: 81 msec ;; SERVER: 151.197.0.38#53(151.197.0.38) ;; WHEN: Thu Jan 27 15:19:15 2011 ;; MSG SIZE rcvd: 52 Cisco: # dig @64.102.255.44 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @64.102.255.44. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39689 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 3601 IN A 206.127.2.71 ;; AUTHORITY SECTION: faithhiway.com. 3600 IN NS dns01.gpn.register.com. faithhiway.com. 3600 IN NS dns04.gpn.register.com. faithhiway.com. 3600 IN NS dns05.gpn.register.com. faithhiway.com. 3600 IN NS dns02.gpn.register.com. faithhiway.com. 3600 IN NS dns03.gpn.register.com. ;; Query time: 105 msec ;; SERVER: 64.102.255.44#53(64.102.255.44) ;; WHEN: Thu Jan 27 15:20:05 2011 ;; MSG SIZE rcvd: 165 OpenDNS: # dig @208.67.222.222 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @208.67.222.222. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12328 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 169507 IN A 207.200.19.162 ;; Query time: 6 msec ;; SERVER: 208.67.222.222#53(208.67.222.222) ;; WHEN: Thu Jan 27 15:19:29 2011 ;; MSG SIZE rcvd: 52 SpeakEasy: # dig @66.93.87.2 ns1.faithhiway.com A ; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_5.3 <<>> @66.93.87.2. ns1.faithhiway.com A ; (1 server found) ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9342 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;ns1.faithhiway.com. IN A ;; ANSWER SECTION: ns1.faithhiway.com. 169323 IN A 207.200.19.162 ;; Query time: 69 msec ;; SERVER: 66.93.87.2#53(66.93.87.2) ;; WHEN: Thu Jan 27 15:19:51 2011 ;; MSG SIZE rcvd: 52 As you can see above, the majority of queries are returning the correct result. But a few (OpenDNS and SpeakEasy in the examples above) are still showing the old IP address. Considering the length of time that has gone by, it seems obvious to me that either we have made a mistake and not thoroughly handled the DNS changes on our end (likely) or there is a problem with either the DNS provider for this domain (Register) or with some of the DNS servers out in the wild (rather unlikely). Any advice on how I can proceed with this? UPDATE (January 31, 2011): First of all, I apologize for the length of both the original question and this update. I contemplated removing some of the excess from the original post but just in case this problem and its solution are helpful to someone else in the future I'm just going to leave everything as it is. Anyway, I've been doing some more research into this problem, and have discovered the following interesting occurrence. While running a check on the glue records for faithhiway.com always resolve correctly, if I go and check a client domain (where ns1.faithhiway.com is authoritative), I get a strange response. It looks like the root servers are returning nsX.faithhiway.com as their old IP addresses still (under Additional Section). Because we have a server still there responding to DNS queries, the trace finishes and returns the correct IP addresses as the final step (again, under Additional Section). The example below uses one of the domains that we use that uses ns1.faithhiway.com as its authoritative DNS server. # dig +trace +nosearch +all +norecurse ignitemail.com ; <<>> DiG 9.2.4 <<>> +trace +nosearch +all +norecurse ignitemail.com ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 46856 ;; flags: qr ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;. IN NS ;; ANSWER SECTION: . 7986 IN NS a.root-servers.net. . 7986 IN NS b.root-servers.net. . 7986 IN NS c.root-servers.net. . 7986 IN NS d.root-servers.net. . 7986 IN NS e.root-servers.net. . 7986 IN NS f.root-servers.net. . 7986 IN NS g.root-servers.net. . 7986 IN NS h.root-servers.net. . 7986 IN NS i.root-servers.net. . 7986 IN NS j.root-servers.net. . 7986 IN NS k.root-servers.net. . 7986 IN NS l.root-servers.net. . 7986 IN NS m.root-servers.net. ;; Query time: 39 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Mon Jan 31 09:22:17 2011 ;; MSG SIZE rcvd: 228 ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16325 ;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 13, ADDITIONAL: 14 ;; QUESTION SECTION: ;ignitemail.com. IN A ;; AUTHORITY SECTION: com. 172800 IN NS h.gtld-servers.net. com. 172800 IN NS m.gtld-servers.net. com. 172800 IN NS i.gtld-servers.net. com. 172800 IN NS l.gtld-servers.net. com. 172800 IN NS c.gtld-servers.net. com. 172800 IN NS k.gtld-servers.net. com. 172800 IN NS d.gtld-servers.net. com. 172800 IN NS f.gtld-servers.net. com. 172800 IN NS b.gtld-servers.net. com. 172800 IN NS a.gtld-servers.net. com. 172800 IN NS e.gtld-servers.net. com. 172800 IN NS g.gtld-servers.net. com. 172800 IN NS j.gtld-servers.net. ;; ADDITIONAL SECTION: a.gtld-servers.net. 172800 IN A 192.5.6.30 a.gtld-servers.net. 172800 IN AAAA 2001:503:a83e::2:30 b.gtld-servers.net. 172800 IN A 192.33.14.30 b.gtld-servers.net. 172800 IN AAAA 2001:503:231d::2:30 c.gtld-servers.net. 172800 IN A 192.26.92.30 d.gtld-servers.net. 172800 IN A 192.31.80.30 e.gtld-servers.net. 172800 IN A 192.12.94.30 f.gtld-servers.net. 172800 IN A 192.35.51.30 g.gtld-servers.net. 172800 IN A 192.42.93.30 h.gtld-servers.net. 172800 IN A 192.54.112.30 i.gtld-servers.net. 172800 IN A 192.43.172.30 j.gtld-servers.net. 172800 IN A 192.48.79.30 k.gtld-servers.net. 172800 IN A 192.52.178.30 l.gtld-servers.net. 172800 IN A 192.41.162.30 ;; Query time: 64 msec ;; SERVER: 198.41.0.4#53(a.root-servers.net) ;; WHEN: Mon Jan 31 09:22:17 2011 ;; MSG SIZE rcvd: 504 ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12860 ;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;ignitemail.com. IN A ;; AUTHORITY SECTION: ignitemail.com. 172800 IN NS ns1.faithhiway.com. ignitemail.com. 172800 IN NS ns2.faithhiway.com. ;; ADDITIONAL SECTION: ns1.faithhiway.com. 172800 IN A 207.200.19.162 ns2.faithhiway.com. 172800 IN A 207.200.50.142 ;; Query time: 152 msec ;; SERVER: 192.54.112.30#53(h.gtld-servers.net) ;; WHEN: Mon Jan 31 09:22:17 2011 ;; MSG SIZE rcvd: 111 ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43016 ;; flags: qr aa; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2 ;; QUESTION SECTION: ;ignitemail.com. IN A ;; ANSWER SECTION: ignitemail.com. 3600 IN A 206.127.2.64 ;; AUTHORITY SECTION: ignitemail.com. 3600 IN NS ns1.faithhiway.com. ignitemail.com. 3600 IN NS ns2.faithhiway.com. ;; ADDITIONAL SECTION: ns1.faithhiway.com. 3600 IN A 206.127.2.71 ns2.faithhiway.com. 3600 IN A 206.127.2.72 ;; Query time: 25 msec ;; SERVER: 206.127.2.71#53(ns1.faithhiway.com) ;; WHEN: Mon Jan 31 09:22:18 2011 ;; MSG SIZE rcvd: 127 I really think this is a problem we have somewhere in our setup, but whether it is ignorance of something with DNS on my or my fellow engineer's end or just a dumb mistake we made, I have yet to find it.

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  • Null reading in stream images? Unable to start activity ComponentInfo

    - by lasmith
    I have reviewed a lot of similar questions regarding not being able to launch an activity but they don't seem to quite match my problem. I am working on a simple black jack game but its force quitting. I suspect there is a problem with loading up the card png images I have. Stepping through the debugger it crashes right while in the resetGame() function. I'm sure I am doing something dumb. My Logcat: 10-15 20:21:43.309: E/AndroidRuntime(2863): FATAL EXCEPTION: main 10-15 20:21:43.309: E/AndroidRuntime(2863): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.smith.blackjack/com.smith.blackjack.Main}: java.lang.NullPointerException 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread.access$600(ActivityThread.java:130) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.os.Handler.dispatchMessage(Handler.java:99) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.os.Looper.loop(Looper.java:137) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread.main(ActivityThread.java:4745) 10-15 20:21:43.309: E/AndroidRuntime(2863): at java.lang.reflect.Method.invokeNative(Native Method) 10-15 20:21:43.309: E/AndroidRuntime(2863): at java.lang.reflect.Method.invoke(Method.java:511) 10-15 20:21:43.309: E/AndroidRuntime(2863): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 10-15 20:21:43.309: E/AndroidRuntime(2863): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 10-15 20:21:43.309: E/AndroidRuntime(2863): at dalvik.system.NativeStart.main(Native Method) 10-15 20:21:43.309: E/AndroidRuntime(2863): Caused by: java.lang.NullPointerException 10-15 20:21:43.309: E/AndroidRuntime(2863): at com.smith.blackjack.DeckOfCards.<init>(DeckOfCards.java:17) 10-15 20:21:43.309: E/AndroidRuntime(2863): at com.smith.blackjack.Main.resetGame(Main.java:98) 10-15 20:21:43.309: E/AndroidRuntime(2863): at com.smith.blackjack.Main.onCreate(Main.java:67) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.Activity.performCreate(Activity.java:5008) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 10-15 20:21:43.309: E/AndroidRuntime(2863): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 10-15 20:21:43.309: E/AndroidRuntime(2863): ... 11 more My androidmanifest: <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.smith.blackjack" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="11" android:targetSdkVersion="15" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".Main" android:label="@string/title_activity_main" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> Here is my Main.java package com.smith.blackjack; import android.os.Bundle; import android.app.Activity; import android.content.res.AssetManager; import android.graphics.drawable.Drawable; import java.io.IOException; import java.io.InputStream; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; public class Main extends Activity { private ImageView dealerCard0; private ImageView dealerCard1; private ImageView dealerCard2; private ImageView dealerCard3; private ImageView playerCard0; private ImageView playerCard1; private ImageView playerCard2; private ImageView playerCard3; private ImageView imgResult; private Button btnDeal; private Button btnDraw; private Button btnHold; private DeckOfCards deckOfCards; private int[] dealerValues; private int dealerSum; private int dealerCardNumber; private int[] playerValues; private int playerSum; private int playerCardNumber; private InputStream dealerHiddenCard; private Card dealerCard; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); dealerCard0 = (ImageView) findViewById(R.id.dealerCard0); dealerCard1 = (ImageView) findViewById(R.id.dealerCard1); dealerCard2 = (ImageView) findViewById(R.id.dealerCard2); dealerCard3 = (ImageView) findViewById(R.id.dealerCard3); playerCard0 = (ImageView) findViewById(R.id.playerCard0); playerCard1 = (ImageView) findViewById(R.id.playerCard1); playerCard2 = (ImageView) findViewById(R.id.playerCard2); playerCard3 = (ImageView) findViewById(R.id.playerCard3); imgResult = (ImageView) findViewById(R.id.imgResult); btnDeal = (Button) findViewById(R.id.deal); btnDraw = (Button) findViewById(R.id.draw); btnHold = (Button) findViewById(R.id.hold); btnDeal.setOnClickListener(btnDealListener); btnDraw.setOnClickListener(btnDrawListener); btnHold.setOnClickListener(btnHoldListener); resetGame(); } private void resetGame(){ AssetManager assets = getAssets(); dealerValues = new int[4]; playerValues = new int[4]; dealerSum = 0; playerSum = 0; dealerCardNumber = 0; playerCardNumber = 0; for (int i = 0; i < 4; i++) { dealerValues[i] = 0; playerValues[i] = 0; } try { InputStream stream = assets.open("cardback.png"); // stream = assets.open("cardback.png"); Drawable cardImage = Drawable.createFromStream(stream, null); dealerCard0.setImageDrawable(cardImage); dealerCard1.setImageDrawable(cardImage); dealerCard2.setImageDrawable(cardImage); dealerCard3.setImageDrawable(cardImage); playerCard0.setImageDrawable(cardImage); playerCard1.setImageDrawable(cardImage); playerCard2.setImageDrawable(cardImage); playerCard3.setImageDrawable(cardImage); imgResult.setImageDrawable(cardImage); deckOfCards = new DeckOfCards(); deckOfCards.shuffle(); assets.close(); } catch (IOException e){ Log.e("Reset Game", "Error Loading", e); } } public OnClickListener btnDealListener = new OnClickListener() { // @Override public void onClick(View v) { try { AssetManager assets = getAssets(); InputStream stream; // first player card Card newCard; newCard = deckOfCards.dealCard(); playerValues[playerCardNumber] = newCard.faceValue; playerCardNumber++; stream = assets.open(newCard.File); Drawable cardImage = Drawable.createFromStream(stream, newCard.File); playerCard0.setImageDrawable(cardImage); assets.close(); // second player card newCard = deckOfCards.dealCard(); playerValues[playerCardNumber] = newCard.faceValue; playerCardNumber++; stream = assets.open(newCard.File); cardImage = Drawable.createFromStream(stream, newCard.File); playerCard1.setImageDrawable(cardImage); assets.close(); // first dealer card hidden newCard = deckOfCards.dealCard(); dealerCard = newCard; dealerValues[dealerCardNumber] = newCard.faceValue; dealerCardNumber++; dealerHiddenCard = assets.open(newCard.File); stream = assets.open("cardback.png"); cardImage = Drawable.createFromStream(stream, "cardback"); dealerCard0.setImageDrawable(cardImage); assets.close(); // second dealer card open newCard = deckOfCards.dealCard(); dealerValues[dealerCardNumber] = newCard.faceValue; dealerCardNumber++; stream = assets.open(newCard.File); cardImage = Drawable.createFromStream(stream, newCard.File); dealerCard1.setImageDrawable(cardImage); assets.close(); } catch (IOException e){ Log.e("Deal", "Error Loading", e); } }; }; public OnClickListener btnDrawListener = new OnClickListener() { // @Override public void onClick(View v) { try { AssetManager assets = getAssets(); InputStream stream; // get next player card Card newCard; newCard = deckOfCards.dealCard(); playerValues[playerCardNumber] = newCard.faceValue; playerCardNumber++; stream = assets.open(newCard.File); Drawable cardImage = Drawable.createFromStream(stream, newCard.File); switch (playerCardNumber){ case 3: playerCard2.setImageDrawable(cardImage); case 4: playerCard3.setImageDrawable(cardImage); } assets.close(); } catch (IOException e){ Log.e("Draw", "Error Loading", e); } }; }; public OnClickListener btnHoldListener = new OnClickListener() { // @Override public void onClick(View v) { Drawable cardImage; // evaluate player hand playerSum = evaluate(playerValues); if (playerSum > 21){ // player losses } // flip over the dealer hidden card cardImage = Drawable.createFromStream(dealerHiddenCard, dealerCard.File); Card newCard; InputStream stream; AssetManager assets = getAssets(); for (int i=2; i<4; i++){ dealerSum = evaluate(dealerValues); if (dealerSum < 16 ) { newCard = deckOfCards.dealCard(); dealerValues[dealerCardNumber] = newCard.faceValue; dealerCardNumber++; try { stream = assets.open(newCard.File); cardImage = Drawable.createFromStream(stream, newCard.File); switch (dealerCardNumber){ case 3: dealerCard2.setImageDrawable(cardImage); case 4: dealerCard3.setImageDrawable(cardImage); } assets.close(); } catch (IOException e){ Log.e("Draw", "Error Loading", e); } if (dealerSum < playerSum) { // player wins } if (dealerSum > playerSum){ // dealer wins } if (dealerSum == playerSum){ // it is a draw } } } }; }; public int evaluate (int[]values) { int sumCards = 0; for (int i = 0; i < 4; i++){ sumCards += values[i]; } if (sumCards > 21) { for (int i = 0; i < 4; i++){ if (values[i] == 11) { values[i] = 1; sumCards -= 10; continue; } } } return sumCards; } } My DeckOfCards class: package com.smith.blackjack; import java.util.Random; public class DeckOfCards { private Card [] deck; private int currentCard; private static final int NUMBER_OF_CARDS = 52; private static final Random randomNumbers = new Random(); public DeckOfCards () { deck = new Card[NUMBER_OF_CARDS]; currentCard = 0 ; for(int count = 0; count < deck.length; count++) { deck[count].faceValue = count + 1; } } public void shuffle () { currentCard = 0; for (int first = 0; first < deck.length; first ++){ int second = randomNumbers.nextInt(NUMBER_OF_CARDS); int temp = deck[first].faceValue; deck[first].faceValue=deck[second].faceValue; deck[second].faceValue = temp; } } public Card dealCard(){ Card temp = new Card(); temp.faceValue = 0; temp.File = ""; if(currentCard < deck.length) { temp.faceValue = deck[currentCard].faceValue / 4; int suit = deck[currentCard].faceValue % 4; String suitString = ""; switch (suit){ case 0: suitString = "c"; case 1: suitString = "d"; case 2: suitString = "h"; case 3: suitString = "s"; } Integer face = temp.faceValue / 4 ; String faceString = face.toString(); temp.File = faceString + suitString + ".png"; switch (temp.faceValue){ case 11: temp.faceValue = 10; case 12: temp.faceValue = 10; case 13: temp.faceValue = 10; } return temp; } else return temp; } }

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