Search Results

Search found 5311 results on 213 pages for 'begin'.

Page 5/213 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • How to save video from a url to disk, also how to begin playback after some buffering?

    - by Shizam
    First question is, given a url to an mp4 video, how can I save that file to disk? The followup to that is while its saving, can I begin playback after its buffered some of the video to disk or do I have to wait for the entire file to be written and then: MPMoviePlayerController* theMovie=[[MPMoviePlayerController alloc] initWithContentURL:theURL]; using the path to the local file. Thanks, Sam

    Read the article

  • How to save video from a url to disk, also how to begin playback after some buffering?

    - by Shizam
    First question is, given a url to an mp4 video, how can I save that file to disk? The followup to that is while its saving, can I begin playback after its buffered some of the video to disk or do I have to wait for the entire file to be written and then: MPMoviePlayerController* theMovie=[[MPMoviePlayerController alloc] initWithContentURL:theURL]; using the path to the local file. Thanks, Sam

    Read the article

  • What does really happen when we do a BEGIN TRAN in SQL Server 2005?

    - by Misnomer
    Hi all, I came across this issue or maybe something I didn't realize but I did a Begin Tran and had some code inside it and never ran a commit or rollback as I forgot about it. That caused all many of the database queries or even just a simple select top 1000 command were just sitting on loading..? Now it probably has put some locks on the tables I guess since it did not let me query them..but I just wanted to know what exactly happened and what are the practices to be followed here ?

    Read the article

  • Does rails do a rollback if I use begin...rescue?

    - by codeman73
    I'd like to add a begin...rescue block to one of my controllers create method, in order to log better info and construct the correct error message to return to the client. Does the rescue in any way 'interrupt' the rollback process? I'm assuming rails automatically does a rollback. When does it happen? Has it already happened by the time I get in the rescue clause? I'm using mySQL on Dreamhost and I think they use innoDB.

    Read the article

  • How to provide stl like container with public const iterator and private non-const iterator?

    - by WilliamKF
    Hello, I am deriving a class privately from std::list and wish to provide public begin() and end() for const_iterator and private begin() and end() for just plain iterator. However, the compiler is seeing the private version and complaining that it is private instead of using the public const version. I understand that C++ will not overload on return type (in this case const_iterator and iterator) and thus it is choosing the non-const version since my object is not const. Short of casting my object to const before calling begin() or not overloading the name begin is there a way to accomplish this? I would think this is a known pattern that folks have solved before and would like to follow suit as to how this is typically solved. class myObject; class myContainer : private std::list<myObject> { public: typedef std::list<myObject>::const_iterator myContainer::const_iterator; private: typedef std::list<myObject>::iterator myContainer::iterator; public: myContainer::const_iterator begin() const { return std::list<myObject>::begin(); } myContainer::const_iterator end() const { return std::list<myObject>::end(); } private: myContainer::iterator begin() { return std::list<myObject>::begin(); } myContainer::iterator end() { return std::list<myObject>::end(); } }; void myFunction(myContainer &container) { myContainer::const_iterator aItr = container.begin(); myContainer::const_iterator aEndItr = container.end(); for (; aItr != aEndItr; ++aItr) { const myObject &item = *aItr; // Do something const on container's contents. } } The error from the compiler is something like this: ../../src/example.h:447: error: `std::_List_iterator<myObject> myContainer::begin()' is private caller.cpp:2393: error: within this context ../../src/example.h:450: error: `std::_List_iterator<myObject> myContainer::end()' is private caller.cpp:2394: error: within this context Thanks. -William

    Read the article

  • SQL Server 2008: CASE vs IF-ELSE-IF vs GOTO

    - by Saharsh Shah
    I have some rules in my application and I have written the business logic of that rules in my procedure. At the time of creation of procedure I came to know that CASE statement won't work in my scenario. So I have tried two ways to perform same operations (using IF-ELSE-IF or GOTO) shown as below. Method 1 Using IF-ELSE-IF conditions: DECLARE @V_RuleId SMALLINT; IF (@V_RuleId = 1) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 2) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 3) BEGIN /*My business logic*/ END /* ... ... ... ...*/ ELSE IF (@V_RuleId = 19) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 20) BEGIN /*My business logic*/ END Method 2 Using GOTO statement: DECLARE @V_RuleId SMALLINT, @V_Temp VARCHAR(100); SET @V_Temp = 'GOTO RULE' + CONVERT(VARCHAR, @V_RuleId); EXECUTE sp_executesql @V_Temp; RULE1: BEGIN /*My business logic*/ END RULE2: BEGIN /*My business logic*/ END RULE3: BEGIN /*My business logic*/ END /* ... ... ... ...*/ RULE19: BEGIN /*My business logic*/ END RULE20: BEGIN /*My business logic*/ END Today I have 20 rules. It can be increase to any number in future. If I can able to use CASE statement then I have not any problem with performance, but I can't do that so I am worried about the performance of my procedure. Also one thing to be noticed that this procedure will execute very frequently by application. My questions are: Is there any way to use CASE statement in my procedure? If not, which method is best to use in my procedure to improve the performance of my code? Thanks in advance...

    Read the article

  • finishing some functions in this code

    - by osabri
    i have problem to finish some functions in this code program lab4; var inFile : text; var pArray : array[1..10]of real; //array of 10 integer values containing patterns to search in a given set of numbers var rArray : array[1..10]of integer; //array containing result of pattern search, each index in rArray coresponds to number of occurences of //pattern from pArray in sArray. var sArray : array[1..100] of real; //array containing data read from file var accuracy : real; (****************************************************************************) function errMsg:integer; begin if ParamCount < 3 then begin writeln('Too few arguments'); writeln('Usage: ./lab4 lab4.txt <accuracy> <pattern_1> <pattern_2> <pattern_n>'); errMsg:=-1; end else if ParamCount > 12 then begin writeln('Too many arguments'); writeln('Maximum number of patterns is 10'); errMsg:=-1; end else begin assign(inFile,ParamStr(1)); {$I-} reset(inFile); if ioresult<>0 then begin writeln('Cannot open ',ParamStr(1)); errMsg:=-1; end else errMsg:=0; end; end; (****************************************************************************) procedure readPattern; var errPos,idx:integer; begin if errMsg=0 then begin for idx:=1 to ParamCount-2 do begin Val(ParamStr(idx+2),pArray[idx],errPos); writeln('pArray:',pArray[idx]:2:2); end; end; end; (****************************************************************************) procedure getAccuracy; //Function should get the accuracy as the first param (after the program name) begin (here where i stopped : (( ) end; (****************************************************************************) function readSet:integer; //Function returns number of elements read from file var idx,errPos:integer; var sChar: string; begin if errMsg=0 then begin idx:=1; repeat begin readln(inFile,sChar); VAL(sChar,sArray[idx],errPos); writeln('sArray:',sArray[idx]:2:2); idx:=idx+1; end until eof(inFile)=TRUE; end; readSet:=idx-1; end; (****************************************************************************) procedure searchPattern(sNumber:integer); //Function should search and count pattern(patterns) occurence in a given set what the best solution for this part?? (****************************************************************************) procedure dispResult; //Function should display the result of pattern(patterns) search begin (****************************************************************************) begin readPattern; getAccuracy; searchPattern(readSet); dispResult; end.

    Read the article

  • Have I to count transactions before rollback one in catch block in T-SQL?

    - by abatishchev
    I have next block in the end of each my stored procedure for SQL Server 2008 BEGIN TRY BEGIN TRAN -- my code COMMIT END TRY BEGIN CATCH IF (@@trancount > 0) BEGIN ROLLBACK DECLARE @message NVARCHAR(MAX) DECLARE @state INT SELECT @message = ERROR_MESSAGE(), @state = ERROR_STATE() RAISERROR (@message, 11, @state) END END CATCH Is it possible to switch CATCH-block to BEGIN CATCH ROLLBACK DECLARE @message NVARCHAR(MAX) DECLARE @state INT SELECT @message = ERROR_MESSAGE(), @state = ERROR_STATE() RAISERROR (@message, 11, @state) END CATCH or just BEGIN CATCH ROLLBACK END CATCH ?

    Read the article

  • algorithms that destruct and copy_construct

    - by FredOverflow
    I am currently building my own toy vector for fun, and I was wondering if there is something like the following in the current or next standard or in Boost? template<class T> void destruct(T* begin, T* end) { while (begin != end) { begin -> ~T(); ++begin; } } template<class T> T* copy_construct(T* begin, T* end, T* dst) { while (begin != end) { new(dst) T(*begin); ++begin; ++dst; } return dst; }

    Read the article

  • C++ STL: Trouble with iterators

    - by Rosarch
    I'm having a beginner problem: bool _isPalindrome(const string& str) { return _isPalindrome(str.begin(), str.end()); // won't compile } bool _isPalindrome(string::iterator begin, string::iterator end) { return begin == end || *begin == *end && _isPalindrome(++begin, --end); } What am I doing wrong here? Why doesn't str.begin() get type checked to be a string::iterator?

    Read the article

  • Games to Vista Game explorer with Inno Setup

    - by Kraemer
    Ok, i'm trying to force my inno setup installer to add a shortcut of my game to Vista Games Explorer. Theoretically this should do the trick: [Files] Source: "GameuxInstallHelper.dll"; DestDir: "{app}"; Flags: ignoreversion overwritereadonly; [Registry] Root: HKLM; Subkey: SOFTWARE\dir\dir; Flags: uninsdeletekeyifempty Root: HKLM; Subkey: SOFTWARE\dir\dir; ValueName: Path; ValueType: String; ValueData: {app}; Flags: uninsdeletekey Root: HKLM; Subkey: SOFTWARE\dir\dir; ValueName: AppFile; ValueType: String; ValueData:{app}\executable.exe ; Flags: uninsdeletekey [CustomMessages] en.Local=en en.removemsg=Do you wish to remove game saves and settings? en.taskentry=Play [Code] const PlayTask = 0; AllUsers = 2; Current = 3; type TGUID = record Data1: Cardinal; Data2, Data3: Word; Data4: array [0..7] of char; end; var GUID: TGUID; function GetDC(HWND: DWord): DWord; external '[email protected] stdcall'; function GetDeviceCaps(DC: DWord; Index: Integer): Integer; external '[email protected] stdcall'; function ReleaseDC(HWND: DWord;DC: DWord): Integer; external '[email protected] stdcall'; function ShowWindow(hWnd: DWord; nCmdShow: Integer): boolean; external '[email protected] stdcall'; function SetWindowLong(hWnd: DWord; nIndex: Integer; dwNewLong: Longint):Longint; external '[email protected] stdcall'; function GenerateGUID(var GUID: TGUID): Cardinal; external 'GenerateGUID@files:GameuxInstallHelper.dll stdcall setuponly'; function AddToGameExplorer(Binary: String; Path: String; InstallType: Integer; var GUID: TGUID): Cardinal; external 'AddToGameExplorerW@files:GameuxInstallHelper.dll stdcall setuponly'; function CreateTask(InstallType: Integer; var GUID: TGUID; TaskType: Integer; TaskNumber: Integer; TaskName: String; Binary: String; Parameters: String): Cardinal; external 'CreateTaskW@files:GameuxInstallHelper.dll stdcall setuponly'; function RetrieveGUIDForApplication(Binary: String; var GUID: TGUID): Cardinal; external 'RetrieveGUIDForApplicationW@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function RemoveFromGameExplorer(var GUID: TGUID): Cardinal; external 'RemoveFromGameExplorer@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function RemoveTasks(var GUID: TGUID): Cardinal; external 'RemoveTasks@{app}\GameuxInstallHelper.dll stdcall uninstallonly'; function InitializeSetup(): Boolean; var appath: string; ResultCode: Integer; begin if RegKeyExists(HKEY_LOCAL_MACHINE, 'SOFTWARE\dir\dir') then begin RegQueryStringValue(HKEY_LOCAL_MACHINE, 'SOFTWARE\dir\dir', 'Path', appath) Exec((appath +'\unins000.exe'), '', '', SW_SHOW, ewWaitUntilTerminated, ResultCode) end else begin Result := TRUE end; end; procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep); begin if CurUninstallStep = usUninstall then begin if GetWindowsVersion shr 24 > 5 then begin RetrieveGUIDForApplication(ExpandConstant('{app}\AWL_Release.dll'), GUID); RemoveFromGameExplorer(GUID); RemoveTasks(GUID); UnloadDll(ExpandConstant('{app}\GameuxInstallHelper.dll')); end; end; if CurUninstallStep = usPostUninstall then begin if MsgBox(ExpandConstant('{cm:removemsg}'), mbConfirmation, MB_YESNO)=IDYES then begin DelTree(ExpandConstant('{app}'), True, True, True); end; end; end; procedure CurStepChanged(CurStep: TSetupStep); begin if GetWindowsVersion shr 24 > 5 then begin if CurStep = ssInstall then GenerateGUID(GUID); if CurStep = ssPostInstall then begin AddToGameExplorer(ExpandConstant('{app}\AWL_Release.dll'), ExpandConstant('{app}'), Current, GUID); CreateTask(3, GUID, PlayTask, 0, ExpandConstant('{cm:taskentry}'), ExpandConstant('{app}\executable.exe'), ''); CreateTask(3, GUID, 1, 0, 'Game Website', 'http://www.gamewebsite.com/', ''); end; end; end; The installer works just fine, but it doesn't place a shortcut of my game to Games explorer. Since i believe that the problem is on the binary file i guess for that part i should ask for some help. So, can anyone please give me a hand here?

    Read the article

  • How to regex match a string of alnums and hyphens, but which doesn't begin or end with a hyphen?

    - by Shahar Evron
    I have some code validating a string of 1 to 32 characters, which may contain only alpha-numerics and hyphens ('-') but may not begin or end with a hyphen. I'm using PCRE regular expressions & PHP (albeit the PHP part is not really important in this case). Right now the pseudo-code looks like this: if (match("/^[\p{L}0-9][\p{L}0-9-]{0,31}$/u", string) and not match("/-$/", string)) print "success!" That is, I'm checking first that the string is of right contents, doesn't being with a '-' and is of the right length, and then I'm running another test to see that it doesn't end with a '-'. Any suggestions on merging this into a single PCRE regular expression? I've tried using look-ahead / look-behind assertions but couldn't get it to work.

    Read the article

  • Interested in embedded systems. Where to begin?

    - by Ala ABUDEEB
    Hello, i'm a computer systems engineering student. i'm interested in designing embedded systems but i don't know where to begin learning this, and what topics are essentially needed to proceed in this domain. So can you please tell me what topics do i have to study, and what books are available there in market or online that can help me??? please help me p.s. normally as an engineering student i have basic knowledge of circuit theory and microcontroller realm. thank you in advance.

    Read the article

  • Virtual drivers with Windows Driver Model - where to begin?

    - by waitinforatrain
    I've never written drivers before but I'm starting an open-source project that involves creating virtual MIDI ports that will send the MIDI data over a network. For this, I presume I would be creating some sort of virtual driver using WDM (unless it's possible with kernel hooks?) - but being a beginner to driver development I don't know where to begin. Does anyone know any useful resources that would help me with this project? Or some open-source code from a similar project that I could fork as a starting point?

    Read the article

  • NSTableView won't begin dragging rows if the mouseDown happens within the rect of an NSButtonCell.

    - by Joel Day
    I currently have an odd case where I need to be able to reorder rows in an NSTableView, but the only column happens to be an NSButtonCell. I'm trying to see how I can override NSButtonCell's mouse tracking in order to get it to behave in a way so that the NSTableView will begin dragging the row, but am not having much luck. Additional info that might affect the behavior: With this NSTableView, I am not allowing any rows to be selected, but I have forced mouse tracking to always occur for all cells. This is so that the button can still be clicked even though its row can never be selected. Thanks!

    Read the article

  • Should the name of my classes begin with 'Q' in Qt?

    - by Venemo
    Hello Everyone, When I first started working with Qt, it was extremely annoying that every class has a name beginning with 'Q', but now I've got used to it. I'm using Qt Creator, and it highlights code quite well. However, it only highlights class names beginning with 'Q'. And it highlights everything beginning with 'Q' even if there is no such type. It doesn't highlight custom class names. That makes me wonder, should I also begin all my class names with 'Q'? Or at least the reusable ones? (I mean, those that I put in a class library, or reuse in another app.) I've seen several places where they named their classes this way. Is it a good thing? I found this page about Qt's naming conventions, but it doesn't deal with this question. Also, I don't understand why Qt doesn't use namespaces.

    Read the article

  • PHP: How to begin testing large, existing codebase, and test for regression on production site?

    - by anonymous coward
    I'm in charge of at least one large body of existing PHP code, that desperately needs tests, and as well I need some method of checking the production site for errors. I've been working with PHP for many years, but am unfortunately new to testing. (Sorry!). While writing tests for code that has predictable outcomes seems easy enough, I'm having trouble wrapping my head around just how I can test the live site, to ensure proper output. I know that in a test environment, I could set up the database in a known state... but are there proper methods or techniques for testing a live site? Where should I begin? [I am aware of PHPUnit and SimpleTest, but haven't chosen one over the other yet]

    Read the article

  • What is the fastest way to reload history commands begin with certain characters in linux?

    - by gerry
    In Dos we can input the first several characters to filter command history and find proper one rapidly. But how to do the same thing in Linux ? for example when I am testing a local server: cd sudo /etc/init.d/vsftpd start wget ... ls emacs ... sudo /etc/init.d/vsftpd restart sudo /etc/init.d/vsftpd stop ... In Dos you can easily type sudo and switch among the three commands beginning with it using arrow keys. But in Linux, is below command the best we can do ? historty | grep sudo I don't like it, because history can easily become a mess, and it also need mouse action.

    Read the article

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

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

    Read the article

  • Delphi 2009 - Strip non alpha numeric from string

    - by Brad
    I've got the following code, and need to strip all non alpha numeric characters. It's not working in delphi 2009 ` unit Unit2; //Used information from // http://stackoverflow.com/questions/574603/what-is-the-fastest-way-of-stripping-non-alphanumeric-characters-from-a-string-in interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; Type TExplodeArray = Array Of String; TForm2 = class(TForm) Memo1: TMemo; ListBox1: TListBox; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } Function Explode ( Const cSeparator, vString : String ) : TExplodeArray; Function Implode ( Const cSeparator : String; Const cArray : TExplodeArray ) : String; Function StripHTML ( S : String ) : String; function allwords(data:string):integer; end; var Form2: TForm2; allword, allphrase: TExplodeArray; implementation {$R *.dfm} Function TForm2.StripHTML ( S : String ) : String; Var TagBegin, TagEnd, TagLength : Integer; Begin TagBegin := Pos ( '<', S ); // search position of first < While ( TagBegin > 0 ) Do Begin // while there is a < in S TagEnd := Pos ( '>', S ); // find the matching > TagLength := TagEnd - TagBegin + 1; Delete ( S, TagBegin, TagLength ); // delete the tag TagBegin := Pos ( '<', S ); // search for next < End; Result := S; // give the result End; Function TForm2.Implode ( Const cSeparator : String; Const cArray : TExplodeArray ) : String; Var i : Integer; Begin Result := ''; For i := 0 To Length ( cArray ) - 1 Do Begin Result := Result + cSeparator + cArray [i]; End; System.Delete ( Result, 1, Length ( cSeparator ) ); End; Function TForm2.Explode ( Const cSeparator, vString : String ) : TExplodeArray; Var i : Integer; S : String; Begin S := vString; SetLength ( Result, 0 ); i := 0; While Pos ( cSeparator, S ) 0 Do Begin SetLength ( Result, Length ( Result ) + 1 ); Result[i] := Copy ( S, 1, Pos ( cSeparator, S ) - 1 ); Inc ( i ); S := Copy ( S, Pos ( cSeparator, S ) + Length ( cSeparator ), Length ( S ) ); End; SetLength ( Result, Length ( Result ) + 1 ); Result[i] := Copy ( S, 1, Length ( S ) ); End; //Copied from JclStrings function StrKeepChars(const S: AnsiString; const Chars: TSysCharSet): AnsiString; var Source, Dest: PChar; begin SetLength(Result, Length(S)); UniqueString(Result); Source := PChar(S); Dest := PChar(Result); while (Source < nil) and (Source^ < #0) do begin if Source^ in Chars then begin Dest^ := Source^; Inc(Dest); end; Inc(Source); end; SetLength(Result, (Longint(Dest) - Longint(PChar(Result))) div SizeOf(AnsiChar)); end; function ReplaceNewlines(const AValue: string): string; var SrcPtr, DestPtr: PChar; begin SrcPtr := PChar(AValue); SetLength(Result, Length(AValue)); DestPtr := PChar(Result); while SrcPtr < {greater than less than} #0 do begin if (SrcPtr[0] = #13) and (SrcPtr[1] = #10) then begin DestPtr[0] := '\'; DestPtr[1] := 't'; Inc(SrcPtr); Inc(DestPtr); end else DestPtr[0] := SrcPtr[0]; Inc(SrcPtr); Inc(DestPtr); end; SetLength(Result, DestPtr - PChar(Result)); end; function StripNonAlphaNumeric(const AValue: string): string; var SrcPtr, DestPtr: PChar; begin SrcPtr := PChar(AValue); SetLength(Result, Length(AValue)); DestPtr := PChar(Result); while SrcPtr < #0 do begin if SrcPtr[0] in ['a'..'z', 'A'..'Z', '0'..'9'] then begin DestPtr[0] := SrcPtr[0]; Inc(DestPtr); end; Inc(SrcPtr); end; SetLength(Result, DestPtr - PChar(Result)); end; function TForm2.allwords(data:string):integer; var i:integer; begin listbox1.Items.add(data); data:= StripHTML ( data ); listbox1.Items.add(data); ////////////////////////////////////////////////////////////// data := StrKeepChars(data, ['A'..'Z', 'a'..'z', '0'..'9']); // Strips out everything data comes back blank in Delphi 2009 ////////////////////////////////////////////////////////////// listbox1.Items.add(data); data := stringreplace(data,' ',' ', [rfReplaceAll, rfIgnoreCase] ); //Replace two spaces with one. listbox1.Items.add(data); allword:= explode(' ',data); { // Converting the following PHP code to Delphi $text = ereg_replace("[^[:alnum:]]", " ", $text); while(strpos($text,' ')!==false) $text = ereg_replace(" ", " ", $text); $text=$string=strtolower($text); $text=explode(" ",$text); return count($text); } for I := 0 to Length(allword) - 1 do listbox1.Items.Add(allword[i]); end; procedure TForm2.Button1Click(Sender: TObject); begin //[^[:alnum:]] allwords(memo1.Text); end; end. ` How else would I go about doing this? Thanks

    Read the article

  • rotating bitmaps. In code.

    - by Marco van de Voort
    Is there a faster way to rotate a large bitmap by 90 or 270 degrees than simply doing a nested loop with inverted coordinates? The bitmaps are 8bpp and typically 2048*2400*8bpp Currently I do this by simply copying with argument inversion, roughly (pseudo code: for x = 0 to 2048-1 for y = 0 to 2048-1 dest[x][y]=src[y][x]; (In reality I do it with pointers, for a bit more speed, but that is roughly the same magnitude) GDI is quite slow with large images, and GPU load/store times for textures (GF7 cards) are in the same magnitude as the current CPU time. Any tips, pointers? An in-place algorithm would even be better, but speed is more important than being in-place. Target is Delphi, but it is more an algorithmic question. SSE(2) vectorization no problem, it is a big enough problem for me to code it in assembler Duplicates How do you rotate a two dimensional array?. Follow up to Nils' answer Image 2048x2700 - 2700x2048 Compiler Turbo Explorer 2006 with optimization on. Windows: Power scheme set to "Always on". (important!!!!) Machine: Core2 6600 (2.4 GHz) time with old routine: 32ms (step 1) time with stepsize 8 : 12ms time with stepsize 16 : 10ms time with stepsize 32+ : 9ms Meanwhile I also tested on a Athlon 64 X2 (5200+ iirc), and the speed up there was slightly more than a factor four (80 to 19 ms). The speed up is well worth it, thanks. Maybe that during the summer months I'll torture myself with a SSE(2) version. However I already thought about how to tackle that, and I think I'll run out of SSE2 registers for an straight implementation: for n:=0 to 7 do begin load r0, <source+n*rowsize> shift byte from r0 into r1 shift byte from r0 into r2 .. shift byte from r0 into r8 end; store r1, <target> store r2, <target+1*<rowsize> .. store r8, <target+7*<rowsize> So 8x8 needs 9 registers, but 32-bits SSE only has 8. Anyway that is something for the summer months :-) Note that the pointer thing is something that I do out of instinct, but it could be there is actually something to it, if your dimensions are not hardcoded, the compiler can't turn the mul into a shift. While muls an sich are cheap nowadays, they also generate more register pressure afaik. The code (validated by subtracting result from the "naieve" rotate1 implementation): const stepsize = 32; procedure rotatealign(Source: tbw8image; Target:tbw8image); var stepsx,stepsy,restx,resty : Integer; RowPitchSource, RowPitchTarget : Integer; pSource, pTarget,ps1,ps2 : pchar; x,y,i,j: integer; rpstep : integer; begin RowPitchSource := source.RowPitch; // bytes to jump to next line. Can be negative (includes alignment) RowPitchTarget := target.RowPitch; rpstep:=RowPitchTarget*stepsize; stepsx:=source.ImageWidth div stepsize; stepsy:=source.ImageHeight div stepsize; // check if mod 16=0 here for both dimensions, if so -> SSE2. for y := 0 to stepsy - 1 do begin psource:=source.GetImagePointer(0,y*stepsize); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(target.imagewidth-(y+1)*stepsize,0); for x := 0 to stepsx - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; // 3 more areas to do, with dimensions // - stepsy*stepsize * restx // right most column of restx width // - stepsx*stepsize * resty // bottom row with resty height // - restx*resty // bottom-right rectangle. restx:=source.ImageWidth mod stepsize; // typically zero because width is // typically 1024 or 2048 resty:=source.Imageheight mod stepsize; if restx>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(source.ImageWidth-restx,0); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(Target.imagewidth-stepsize,Target.imageheight-restx); for y := 0 to stepsy - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize*RowPitchSource); dec(ptarget,stepsize); end; end; if resty>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(0,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,0); for x := 0 to stepsx - 1 do begin for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; if (resty>0) and (restx>0) then begin // another loop less, since only one block psource:=source.GetImagePointer(source.ImageWidth-restx,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,target.ImageHeight-restx); for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; end; end;

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >