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  • Need help unformatting text

    - by Axilus
    I am currently programming a Visual C# service to receive emails from various sources then I take certain info and organize it in a database using Regex to retrieve the deferent cell values (such as header, body, problem, cost, etc.etc.). My problem is that I am currently using a Hotmail account to email the service which the service then extracts data and writes it to a csv file; however this is all going fine an dandy except for the fact that the text is formated so when there is a "\n" or something of the sort, the program decides to not input the data that follows that into the cell. For instance, if I emailed this: Cost:$1000.00 Body: Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed vulputate mattis dolor, a dapibus turpis lacinia mollis. Fusce in enim nulla, sit amet gravida dolor. Suspendisse at nisi velit, vel ornare odio. Integer metus justo, imperdiet et pellentesque in, facilisis dignissim metus. Suspendisse potenti. Vivamus purus nisl, hendrerit sit amet rutrum eu, euismod in felis. Maecenas blandit, metus ac eleifend vulputate, nibh ligula mollis mi, non malesuada nunc tellus ac risus. In at rutrum elit. Proin metus sem, ullamcorper ut rhoncus sed, semper nec tellus. Maecenas adipiscing nisl nec elit egestas vel bibendum justo vehicula. Aliquam erat volutpat. Nullam fermentum enim in magna consequat a lacinia felis iaculis. Ut odio justo, consectetur nec cursus eu, dignissim non sapien. Duis tincidunt fringilla aliquet. Vivamus elementum lobortis massa vel posuere. Aenean non congue odio. Aenean aliquam elit volutpat tortor tempor pharetra. Mauris non est eu orci ultricies lacinia. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Ut vitae orci lectus, sit amet convallis nunc. Vivamus feugiat ante at justo auctor at pretium ante congue. In hac habitasse platea dictumst. Sed at feugiat odio. The body cell would look as follows: <span class=3D"ecxecxApple-style-s= pan" style=3D"font-family:Arial=2C Helvetica=2C sans=3Bfont-size:11px"><p s= tyle=3D"text-align:justify=3Bfont-size:11px=3Bline-height:14px=3Bmargin-rig= ht:0px=3Bmargin-bottom:14px=3Bmargin-left:0px=3Bpadding-top:0px=3Bpadding-r= ight:0px=3Bpadding-bottom:0px=3Bpadding-left:0px">Lorem ipsum dolor sit ame= t=2C consectetur adipiscing elit. Praesent in augue nec justo tempor varius= eu et tellus. Nunc id massa tortor=2C ut lobortis sem. Class aptent taciti= sociosqu ad litora torquent per conubia nostra=2C per inceptos himenaeos. = Maecenas quis nisl nec quam tristique posuere sed at nibh. Cras fringilla v= estibulum metus vel porttitor. Cras iaculis=2C erat nec gravida accumsan=2C= metus felis vestibulum risus=2C quis venenatis nisl nulla sed diam. Aenean= quis viverra velit. Etiam quis massa lectus=2C faucibus facilisis sem. Cur= abitur non eros tellus. Sed at ligula neque. Donec elementum rhoncus volutp= at. Curabitur eu accumsan erat. Phasellus auctor odio dolor=2C ut ornare au= gue. Suspendisse vel est nibh. Vivamus facilisis placerat augue sit amet al= iquam. Maecenas viverra=2C ipsum a tincidunt elementum=2C arcu tellus rutru= m ipsum=2C et dignissim urna orci ac mi. Vivamus non odio massa. Nulla cong= ue massa eu leo pretium non consequat urna molestie.</p><p style=3D"text-al= ign:justify=3Bfont-size:11px=3Bline-height:14px=3Bmargin-right:0px=3Bmargin= -bottom:14px=3Bmargin-left:0px=3Bpadding-top:0px=3Bpadding-right:0px=3Bpadd= ing-bottom:0px=3Bpadding-left:0px">Integer neque odio=2C scelerisque at mol= estie quis=2C congue sed arcu. Praesent a arcu odio. Donec sollicitudin=2C = quam vel tincidunt lobortis=2C urna augue cursus lorem=2C in eleifend nunc = risus nec neque. Donec euismod mauris non nibh blandit sollicitudin. Vivamu= s sed tincidunt augue. Suspendisse iaculis massa ut tellus rutrum auctor. C= ras venenatis consequat urna in viverra. Ut blandit imperdiet dolor non sce= lerisque. Suspendisse potenti. Sed vitae lacus ac odio euismod tempus. Aene= an ut sem odio. Curabitur auctor purus a diam iaculis facilisis. Integer mo= lestie commodo mauris a imperdiet. Nunc aliquet tempus orci sit amet viverr= a.</p><p style=3D"text-align:justify=3Bfont-size:11px=3Bline-height:14px=3B= margin-right:0px=3Bmargin-bottom:14px=3Bmargin-left:0px=3Bpadding-top:0px= =3Bpadding-right:0px=3Bpadding-bottom:0px=3Bpadding-left:0px">Morbi ultrici= es fermentum magna=2C et ultricies urna convallis non. Aenean nibh felis=2C= faucibus et pellentesque ultrices=2C accumsan a ligula. Aliquam vulputate = nisi vitae mi pretium et pretium nulla aliquet. Nam egestas diam vel elit c= ommodo fermentum. Aenean venenatis bibendum tellus=2C eget scelerisque risu= s consequat ut. In porta interdum eleifend. Cras laoreet venenatis pulvinar= .. Praesent ultricies tristique lorem=2C quis interdum arcu scelerisque nec.= Quisque arcu tellus=2C consectetur vel mattis nec=2C feugiat ac quam. Prae= sent sit amet fermentum nulla. Nulla lobortis=2C odio vitae elementum aucto= r=2C libero turpis condimentum mi=2C sed aliquet felis sapien nec tortor. I= nteger vehicula=2C neque in egestas accumsan=2C felis metus sagittis nulla= =2C eu dapibus ligula ipsum ut sapien. Nulla quis urna tortor=2C sed facili= sis leo. In at metus sed velit venenatis varius. Fusce aliquam mattis enim= =2C vitae tincidunt sem cursus in.</p><p style=3D"text-align:justify=3Bfont= -size:11px=3Bline-height:14px=3Bmargin-right:0px=3Bmargin-bottom:14px=3Bmar= gin-left:0px=3Bpadding-top:0px=3Bpadding-right:0px=3Bpadding-bottom:0px=3Bp= adding-left:0px">Proin tincidunt ligula at ligula bibendum vitae condimentu= m nunc congue. Curabitur ac magna nibh=2C vel accumsan nisl. Duis nec eros = et purus vestibulum tincidunt at sit amet libero. Donec eu nibh eros. Pelle= ntesque habitant morbi tristique senectus et netus et malesuada fames ac tu= rpis egestas. Donec accumsan=2C tellus at luctus faucibus=2C est nibh sempe= r diam=2C vitae adipiscing lorem tellus vel nulla. Donec eget ipsum ut lore= m tristique ultricies. Aliquam sem diam=2C semper sit amet volutpat pretium= =2C lobortis et eros. Sed vel iaculis metus. Phasellus malesuada elementum = porta.</p><p style=3D"text-align:justify=3Bfont-size:11px=3Bline-height:14p= x=3Bmargin-right:0px=3Bmargin-bottom:14px=3Bmargin-left:0px=3Bpadding-top:0= px=3Bpadding-right:0px=3Bpadding-bottom:0px=3Bpadding-left:0px">Fusce tinci= dunt dignissim massa quis dapibus. Sed aliquet consequat orci=2C eu cursus = libero dapibus vitae. Pellentesque at felis felis=2C vitae condimentum libe= ro. Vivamus eros erat=2C elementum et tristique vitae=2C mattis et neque. P= raesent bibendum leo ac tortor congue id mollis libero ornare. Pellentesque= adipiscing accumsan mi=2C a bibendum purus dignissim id. Cum sociis natoqu= e penatibus et magnis dis parturient montes=2C nascetur ridiculus mus. Morb= i mollis nisi in nibh cursus facilisis. Ut eu quam dolor=2C sit amet congue= orci. Aliquam quam dolor=2C viverra vitae varius sed=2C molestie et quam. = Suspendisse purus mauris=2C fermentum condimentum pharetra at=2C molestie a= nunc. Nam rhoncus euismod venenatis. Nam pellentesque quam ac ipsum volutp= at a eleifend odio imperdiet. Class aptent taciti sociosqu ad litora torque= nt per conubia nostra=2C per inceptos himenaeos. Nulla in nunc magna. Lorem= ipsum dolor sit amet=2C consectetur adipiscing elit. Donec pretium tincidu= nt gravida.</p></span> As you can tell I need a way to get rid of all that html junk and make it readable again. Is there anyway to do this with Regex? Or an easier way if possible. Cheers

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  • Why shouldn't I always use nullable types in C#.

    - by Matthew Vines
    I've been searching for some good guidance on this since the concept was introduced in .net 2.0. Why would I ever want to use non-nullable data types in c#? (A better question is why wouldn't I choose nullable types by default, and only use non-nullable types when that explicitly makes sense.) Is there a 'significant' performance hit to choosing a nullable data type over its non-nullable peer? I much prefer to check my values against null instead of Guid.empty, string.empty, DateTime.MinValue,<= 0, etc, and to work with nullable types in general. And the only reason I don't choose nullable types more often is the itchy feeling in the back of my head that makes me feel like it's more than backwards compatibility that forces that extra '?' character to explicitly allow a null value. Is there anybody out there that always (most always) chooses nullable types rather than non-nullable types? Thanks for your time,

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  • Java: volatile guarantees and out-of-order execution

    - by WizardOfOdds
    Note that this question is solely about the volatile keyword and the volatile guarantees: it is not about the synchronized keyword (so please don't answer "you must use synchronize" for I don't have any issue to solve: I simply want to understand the volatile guarantees (or lack of guarantees) regarding out-of-order execution). Say we have an object containing two volatile String references that are initialized to null by the constructor and that we have only one way to modify the two String: by calling setBoth(...) and that we can only set their references afterwards to non-null reference (only the constructor is allowed to set them to null). For example (it's just an example, there's no question yet): public class SO { private volatile String a; private volatile String b; public SO() { a = null; b = null; } public void setBoth( @NotNull final String one, @NotNull final String two ) { a = one; b = two; } public String getA() { return a; } public String getB() { return b; } } In setBoth(...), the line assigning the non-null parameter "a" appears before the line assigning the non-null parameter "b". Then if I do this (once again, there's no question, the question is coming next): if ( so.getB() != null ) { System.out.println( so.getA().length ); } Am I correct in my understanding that due to out-of-order execution I can get a NullPointerException? In other words: there's no guarantee that because I read a non-null "b" I'll read a non-null "a"? Because due to out-of-order (multi)processor and the way volatile works "b" could be assigned before "a"? volatile guarantees that reads subsequent to a write shall always see the last written value, but here there's an out-of-order "issue" right? (once again, the "issue" is made on purpose to try to understand the semantics of the volatile keyword and the Java Memory Model, not to solve a problem).

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  • Persistence classes in Qt

    - by zarzych
    Hi, I'm porting a medium-sized CRUD application from .Net to Qt and I'm looking for a pattern for creating persistence classes. In .Net I usually created abstract persistence class with basic methods (insert, update, delete, select) for example: public class DAOBase<T> { public T GetByPrimaryKey(object primaryKey) {...} public void DeleteByPrimaryKey(object primaryKey) {...} public List<T> GetByField(string fieldName, object value) {...} public void Insert(T dto) {...} public void Update(T dto) {...} } Then, I subclassed it for specific tables/DTOs and added attributes for DB table layout: [DBTable("note", "note_id", NpgsqlTypes.NpgsqlDbType.Integer)] [DbField("note_id", NpgsqlTypes.NpgsqlDbType.Integer, "NoteId")] [DbField("client_id", NpgsqlTypes.NpgsqlDbType.Integer, "ClientId")] [DbField("title", NpgsqlTypes.NpgsqlDbType.Text, "Title", "")] [DbField("body", NpgsqlTypes.NpgsqlDbType.Text, "Body", "")] [DbField("date_added", NpgsqlTypes.NpgsqlDbType.Date, "DateAdded")] class NoteDAO : DAOBase<NoteDTO> { } Thanks to .Net reflection system I was able to achieve heavy code reuse and easy creation of new ORMs. The simplest way to do this kind of stuff in Qt seems to be using model classes from QtSql module. Unfortunately, in my case they provide too abstract an interface. I need at least transactions support and control over individual commits which QSqlTableModel doesn't provide. Could you give me some hints about solving this problem using Qt or point me to some reference materials? Update: Based on Harald's clues I've implemented a solution that is quite similar to the .Net classes above. Now I have two classes. UniversalDAO that inherits QObject and deals with QObject DTOs using metatype system: class UniversalDAO : public QObject { Q_OBJECT public: UniversalDAO(QSqlDatabase dataBase, QObject *parent = 0); virtual ~UniversalDAO(); void insert(const QObject &dto); void update(const QObject &dto); void remove(const QObject &dto); void getByPrimaryKey(QObject &dto, const QVariant &key); }; And a generic SpecializedDAO that casts data obtained from UniversalDAO to appropriate type: template<class DTO> class SpecializedDAO { public: SpecializedDAO(UniversalDAO *universalDao) virtual ~SpecializedDAO() {} DTO defaultDto() const { return DTO; } void insert(DTO dto) { dao->insert(dto); } void update(DTO dto) { dao->update(dto); } void remove(DTO dto) { dao->remove(dto); } DTO getByPrimaryKey(const QVariant &key); }; Using the above, I declare the concrete DAO class as following: class ClientDAO : public QObject, public SpecializedDAO<ClientDTO> { Q_OBJECT public: ClientDAO(UniversalDAO *dao, QObject *parent = 0) : QObject(parent), SpecializedDAO<ClientDTO>(dao) {} }; From within ClientDAO I have to set some database information for UniversalDAO. That's where my implementation gets ugly because I do it like this: QMap<QString, QString> fieldMapper; fieldMapper["client_id"] = "clientId"; fieldMapper["name"] = "firstName"; /* ...all column <-> field pairs in here... */ dao->setFieldMapper(fieldMapper); dao->setTable("client"); dao->setPrimaryKey("client_id"); I do it in constructor so it's not visible at a first glance for someone browsing through the header. In .Net version it was easy to spot and understand. Do you have some ideas how I could make it better?

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  • My linux server takes more than an hour to boot. Suggestions?

    - by jamieb
    I am building a CentOS 5.4 system that boots off a compact flash card using a card reader that emulates an IDE drive. It literally takes about an hour to boot. The ultra-slow part occurs when Grub is loading the kernel. Once that's done, the rest of the boot process only takes about a minute to get to a login prompt. Does anyone have any suggestions? I suspect that it may have to do with UDMA. Everything IDE-related in my BIOS seems to checkout. The read performance hdparm is telling me 1.77 MB/s. Ouch! (But even at that rate, it still shouldn't take an hour to decompress and load the kernel) [root@server ~]# hdparm -tT /dev/hdc /dev/hdc: Timing cached reads: 2444 MB in 2.00 seconds = 1222.04 MB/sec Timing buffered disk reads: 6 MB in 3.39 seconds = 1.77 MB/sec Trying to enable DMA is a no-go though: [root@server ~]# hdparm -d1 /dev/hdc /dev/hdc: setting using_dma to 1 (on) HDIO_SET_DMA failed: Operation not permitted using_dma = 0 (off) Here's some command outputs that might help: System [root@server ~]# uname -a Linux server.localdomain 2.6.18-164.el5xen #1 SMP Thu Sep 3 04:47:32 EDT 2009 i686 i686 i386 GNU/Linux PCI info: [root@server ~]# lspci -v 00:00.0 Host bridge: Intel Corporation 82945G/GZ/P/PL Memory Controller Hub (rev 02) Subsystem: Intel Corporation 82945G/GZ/P/PL Memory Controller Hub Flags: bus master, fast devsel, latency 0 Capabilities: [e0] Vendor Specific Information 00:02.0 VGA compatible controller: Intel Corporation 82945G/GZ Integrated Graphics Controller (rev 02) (prog-if 00 [VGA controller]) Subsystem: Intel Corporation 82945G/GZ Integrated Graphics Controller Flags: bus master, fast devsel, latency 0, IRQ 10 Memory at fdf00000 (32-bit, non-prefetchable) [size=512K] I/O ports at ff00 [size=8] Memory at d0000000 (32-bit, prefetchable) [size=256M] Memory at fdf80000 (32-bit, non-prefetchable) [size=256K] Capabilities: [90] Message Signalled Interrupts: 64bit- Queue=0/0 Enable- Capabilities: [d0] Power Management version 2 00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 (rev 01) (prog-if 00 [UHCI]) Subsystem: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #1 Flags: bus master, medium devsel, latency 0, IRQ 16 I/O ports at fe00 [size=32] 00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 (rev 01) (prog-if 00 [UHCI]) Subsystem: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #2 Flags: bus master, medium devsel, latency 0, IRQ 17 I/O ports at fd00 [size=32] 00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 (rev 01) (prog-if 00 [UHCI]) Subsystem: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #3 Flags: bus master, medium devsel, latency 0, IRQ 18 I/O ports at fc00 [size=32] 00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 (rev 01) (prog-if 00 [UHCI]) Subsystem: Intel Corporation 82801G (ICH7 Family) USB UHCI Controller #4 Flags: bus master, medium devsel, latency 0, IRQ 19 I/O ports at fb00 [size=32] 00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller (rev 01) (prog-if 20 [EHCI]) Subsystem: Intel Corporation 82801G (ICH7 Family) USB2 EHCI Controller Flags: bus master, medium devsel, latency 0, IRQ 16 Memory at fdfff000 (32-bit, non-prefetchable) [size=1K] Capabilities: [50] Power Management version 2 Capabilities: [58] Debug port 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1) (prog-if 01 [Subtractive decode]) Flags: bus master, fast devsel, latency 0 Bus: primary=00, secondary=01, subordinate=01, sec-latency=32 I/O behind bridge: 0000d000-0000dfff Memory behind bridge: fde00000-fdefffff Prefetchable memory behind bridge: 00000000fdd00000-00000000fdd00000 Capabilities: [50] #0d [0000] 00:1f.0 ISA bridge: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge (rev 01) Subsystem: Intel Corporation 82801GB/GR (ICH7 Family) LPC Interface Bridge Flags: bus master, medium devsel, latency 0 Capabilities: [e0] Vendor Specific Information 00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller (rev 01) (prog-if 80 [Master]) Subsystem: Intel Corporation 82801GB/GR/GH (ICH7 Family) SATA IDE Controller Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 17 I/O ports at <unassigned> I/O ports at <unassigned> I/O ports at <unassigned> I/O ports at <unassigned> I/O ports at f800 [size=16] Capabilities: [70] Power Management version 2 00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 01) Subsystem: Intel Corporation 82801G (ICH7 Family) SMBus Controller Flags: medium devsel, IRQ 17 I/O ports at 0500 [size=32] 01:04.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10) Subsystem: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ Flags: bus master, medium devsel, latency 32, IRQ 18 I/O ports at de00 [size=256] Memory at fdeff000 (32-bit, non-prefetchable) [size=256] Capabilities: [50] Power Management version 2 01:06.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10) Subsystem: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ Flags: bus master, medium devsel, latency 32, IRQ 17 I/O ports at dc00 [size=256] Memory at fdefe000 (32-bit, non-prefetchable) [size=256] Capabilities: [50] Power Management version 2 01:07.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10) Subsystem: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ Flags: bus master, medium devsel, latency 32, IRQ 19 I/O ports at da00 [size=256] Memory at fdefd000 (32-bit, non-prefetchable) [size=256] Capabilities: [50] Power Management version 2 hdparm ouput: [root@server ~]# hdparm /dev/hdc /dev/hdc: multcount = 0 (off) IO_support = 0 (default 16-bit) unmaskirq = 0 (off) using_dma = 0 (off) keepsettings = 0 (off) readonly = 0 (off) readahead = 256 (on) geometry = 8146/16/63, sectors = 8211168, start = 0 [root@server ~]# hdparm -I /dev/hdc /dev/hdc: ATA device, with non-removable media Model Number: InnoDisk Corp. - iCF4000 4GB Serial Number: 20091023AACA70000753 Firmware Revision: 081107 Standards: Supported: 5 Likely used: 6 Configuration: Logical max current cylinders 8146 8146 heads 16 16 sectors/track 63 63 -- CHS current addressable sectors: 8211168 LBA user addressable sectors: 8211168 device size with M = 1024*1024: 4009 MBytes device size with M = 1000*1000: 4204 MBytes (4 GB) Capabilities: LBA, IORDY(can be disabled) Standby timer values: spec'd by Vendor R/W multiple sector transfer: Max = 2 Current = 2 DMA: mdma0 mdma1 mdma2 udma0 udma1 *udma2 udma3 udma4 Cycle time: min=120ns recommended=120ns PIO: pio0 pio1 pio2 pio3 pio4 Cycle time: no flow control=120ns IORDY flow control=120ns Commands/features: Enabled Supported: * Power Management feature set * WRITE_BUFFER command * READ_BUFFER command * NOP cmd * CFA feature set * Mandatory FLUSH_CACHE HW reset results: CBLID- above Vih Device num = 0 CFA power mode 1: enabled and required by some commands Maximum current = 100ma Checksum: correct

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  • Qt Linker Errors

    - by Kyle Rozendo
    Hi All, I've been trying to get Qt working (QCreator, QIde and now VS2008). I have sorted out a ton of issues already, but I am now faced with the following build errors, and frankly I'm out of ideas. Error 1 error LNK2019: unresolved external symbol "public: void __thiscall FileVisitor::processFileList(class QStringList)" (?processFileList@FileVisitor@@QAEXVQStringList@@@Z) referenced in function _main codevisitor-test.obj Question1 Error 2 error LNK2019: unresolved external symbol "public: void __thiscall FileVisitor::processEntry(class QString)" (?processEntry@FileVisitor@@QAEXVQString@@@Z) referenced in function _main codevisitor-test.obj Question1 Error 3 error LNK2019: unresolved external symbol "public: class QString __thiscall ArgumentList::getSwitchArg(class QString,class QString)" (?getSwitchArg@ArgumentList@@QAE?AVQString@@V2@0@Z) referenced in function _main codevisitor-test.obj Question1 Error 4 error LNK2019: unresolved external symbol "public: bool __thiscall ArgumentList::getSwitch(class QString)" (?getSwitch@ArgumentList@@QAE_NVQString@@@Z) referenced in function _main codevisitor-test.obj Question1 Error 5 error LNK2019: unresolved external symbol "public: void __thiscall ArgumentList::argsToStringlist(int,char * * const)" (?argsToStringlist@ArgumentList@@QAEXHQAPAD@Z) referenced in function "public: __thiscall ArgumentList::ArgumentList(int,char * * const)" (??0ArgumentList@@QAE@HQAPAD@Z) codevisitor-test.obj Question1 Error 6 error LNK2019: unresolved external symbol "public: __thiscall FileVisitor::FileVisitor(class QString,bool,bool)" (??0FileVisitor@@QAE@VQString@@_N1@Z) referenced in function "public: __thiscall CodeVisitor::CodeVisitor(class QString,bool)" (??0CodeVisitor@@QAE@VQString@@_N@Z) codevisitor-test.obj Question1 Error 7 error LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __thiscall FileVisitor::metaObject(void)const " (?metaObject@FileVisitor@@UBEPBUQMetaObject@@XZ) codevisitor-test.obj Question1 Error 8 error LNK2001: unresolved external symbol "public: virtual void * __thiscall FileVisitor::qt_metacast(char const *)" (?qt_metacast@FileVisitor@@UAEPAXPBD@Z) codevisitor-test.obj Question1 Error 9 error LNK2001: unresolved external symbol "public: virtual int __thiscall FileVisitor::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@FileVisitor@@UAEHW4Call@QMetaObject@@HPAPAX@Z) codevisitor-test.obj Question1 Error 10 error LNK2001: unresolved external symbol "protected: virtual bool __thiscall FileVisitor::skipDir(class QDir const &)" (?skipDir@FileVisitor@@MAE_NABVQDir@@@Z) codevisitor-test.obj Question1 Error 11 fatal error LNK1120: 10 unresolved externals ... \Visual Studio 2008\Projects\Assignment1\Question1\Question1\Debug\Question1.exe Question1 The code is as follows: #include "argumentlist.h" #include <codevisitor.h> #include <QDebug> void usage(QString appname) { qDebug() << appname << " Usage: \n" << "codevisitor [-r] [-d startdir] [-f filter] [file-list]\n" << "\t-r \tvisitor will recurse into subdirs\n" << "\t-d startdir\tspecifies starting directory\n" << "\t-f filter\tfilename filter to restrict visits\n" << "\toptional list of files to be visited"; } int main(int argc, char** argv) { ArgumentList al(argc, argv); QString appname = al.takeFirst(); /* app name is always first in the list. */ if (al.count() == 0) { usage(appname); exit(1); } bool recursive(al.getSwitch("-r")); QString startdir(al.getSwitchArg("-d")); QString filter(al.getSwitchArg("-f")); CodeVisitor cvis(filter, recursive); if (startdir != QString()) { cvis.processEntry(startdir); } else if (al.size()) { cvis.processFileList(al); } else return 1; qDebug() << "Files Processed: %d" << cvis.getNumFiles(); qDebug() << cvis.getResultString(); return 0; } Thanks in advance, I'm simply stumped.

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  • How to immediate send mail without prompt confirmation dialog

    - by lmengyew
    I'm using Delphi XE3 and below is my sample application: unit Unit1; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls; type TForm1 = class(TForm) Button1: TButton; procedure Button1Click(Sender: TObject); private function Send(const FromAddr, ToAddr, Subject: String; const AttachFiles: array of string; const MsgBody: String): boolean; end; var Form1: TForm1; implementation uses Winapi.Mapi; {$R *.dfm} procedure TForm1.Button1Click(Sender: TObject); begin Send('', '[email protected]', 'test', [], ''); end; function TForm1.Send(const FromAddr, ToAddr, Subject: String; const AttachFiles: array of string; const MsgBody: String): boolean; var Msg: TMapiMessage; lpSender, lpRecipient: TMapiRecipDesc; Attach: array of TMapiFileDesc; SMTP: TFNMapiSendMail; MAPIModule: HModule; i: integer; S: string; begin Result := False; FillChar(Msg, SizeOf(Msg), 0); Msg.lpszSubject := PAnsiChar(UTF8String(Subject)); Msg.lpszNoteText := PAnsiChar(UTF8String(MsgBody)); if FromAddr <> '' then begin lpSender.ulRecipClass := MAPI_ORIG; lpSender.lpszName := PAnsiChar(UTF8String(FromAddr)); lpSender.lpszAddress := PAnsiChar(UTF8String(FromAddr)); lpSender.ulReserved := 0; lpSender.ulEIDSize := 0; lpSender.lpEntryID := Nil; Msg.lpOriginator := @lpSender; end; if ToAddr <> '' then begin lpRecipient.ulRecipClass := MAPI_TO; lpRecipient.lpszName := PAnsiChar(UTF8String(ToAddr)); lpRecipient.lpszAddress := PAnsiChar(UTF8String(ToAddr)); lpRecipient.ulReserved := 0; lpRecipient.ulEIDSize := 0; lpRecipient.lpEntryID := Nil; Msg.nRecipCount := 1; Msg.lpRecips := @lpRecipient; end; SetLength(Attach, Length(AttachFiles)); FillChar(Attach[0], Length(Attach) * SizeOf(TMapiFileDesc), 0); i := 0; for S in AttachFiles do begin Attach[i].nPosition := Cardinal($FFFFFFFF); Attach[i].lpszPathName := PAnsiChar(UTF8String(S)); Inc(i); end; Msg.nFileCount := Length(AttachFiles); if Msg.nFileCount = 0 then Msg.lpFiles := nil else Msg.lpFiles := @Attach[0]; MAPIModule := LoadLibrary(PChar(MAPIDLL)); if MAPIModule <> 0 then begin try @SMTP := GetProcAddress(MAPIModule, 'MAPISendMail'); if @SMTP <> nil then Result := SMTP(0, Application.Handle, Msg, 0, 0) = SUCCESS_SUCCESS; finally FreeLibrary(MAPIModule); end; end; end; end. When i click the Button1, it will prompt the confirmation dialog as print screen. My question is how to immediate send mail without prompt the confirmation dialog? Is this possible to achieve?

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  • how to effectively modify index

    - by daedlus
    Hej everyone, problem : I am looking for right way to convert an index from clustered to non-clustered Description : I have a table as below in sybase db: dbo.UserLog Id | UserId |time | .... This is hash partitioned using UserId. Currently it has 2 indexes UserId : non-clustered time: clustered This table has about 20 million records. I now want to make UserId as clustered index and time as non-clustered index. is it correct to user alter index to change from clustered to non-clustered or do i drop index and recreate. does the fact that userId is used in hash partitioning have any implications to this? To me alter seems way to go but I have not yet tried this.

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  • Divide a large amount of text on an arbitrary number of equal parts.

    - by kalininew
    I probably already fed up with their stupid questions, but I have one more question. I have a large piece of text <p> Sed ut perspiciatis, unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam eaque ipsa, quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt, explicabo. Nemo enim ipsam voluptatem, quia voluptas sit, </p> <p> aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos, qui ratione voluptatem sequi nesciunt, neque porro quisquam est, qui dolorem ipsum, quia dolor sit, amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt, ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? </p> <p> Quis autem vel eum iure reprehenderit, qui in ea voluptate velit esse, quam nihil molestiae consequatur, vel illum, qui dolorem eum fugiat, quo voluptas nulla pariatur? At vero eos et accusamus et iusto odio dignissimos ducimus, qui blanditiis praesentium voluptatum deleniti atque corrupti, quos dolores et quas molestias excepturi sint, obcaecati cupiditate non provident, similique sunt in culpa, qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum </p> <p> soluta nobis est eligendi optio, cumque nihil impedit, quo minus id, quod maxime placeat, facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet, ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat. </p> <p> Sed ut perspiciatis, unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam eaque ipsa, quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt, explicabo. Nemo enim ipsam voluptatem, quia voluptas sit, </p> <p> Sed ut perspiciatis, unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam eaque ipsa, quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt, explicabo. Nemo enim ipsam voluptatem, quia voluptas sit, </p> <p> aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos, qui ratione voluptatem sequi nesciunt, neque porro quisquam est, qui dolorem ipsum, quia dolor sit, amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt, ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? </p> <p> Quis autem vel eum iure reprehenderit, qui in ea voluptate velit esse, quam nihil molestiae consequatur, vel illum, qui dolorem eum fugiat, quo voluptas nulla pariatur? At vero eos et accusamus et iusto odio dignissimos ducimus, qui blanditiis praesentium voluptatum deleniti atque corrupti, quos dolores et quas molestias excepturi sint, obcaecati cupiditate non provident, similique sunt in culpa, qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum </p> <p> soluta nobis est eligendi optio, cumque nihil impedit, quo minus id, quod maxime placeat, facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet, ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat. </p> <p> Quis autem vel eum iure reprehenderit, qui in ea voluptate velit esse, quam nihil molestiae consequatur, vel illum, qui dolorem eum fugiat, quo voluptas nulla pariatur? At vero eos et accusamus et iusto odio dignissimos ducimus, qui blanditiis praesentium voluptatum deleniti atque corrupti, quos dolores et quas molestias excepturi sint, obcaecati cupiditate non provident, similique sunt in culpa, qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum </p> <p> Sed ut perspiciatis, unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam eaque ipsa, quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt, explicabo. Nemo enim ipsam voluptatem, quia voluptas sit, </p> <p> soluta nobis est eligendi optio, cumque nihil impedit, quo minus id, quod maxime placeat, facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet, ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat. </p> <p> Sed ut perspiciatis, unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam eaque ipsa, quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt, explicabo. Nemo enim ipsam voluptatem, quia voluptas sit, </p> At the exit I need to divide the text on the "n" equal parts, so that in these parts was about the same amount of text. Then I these part are arranged in columns and the need for these columns look about the same height. Another condition: Tags you can break (I mean that if the tag "p" contains a lot of text, it can be divided into two parts, to bring in another column). I think this is a monumental task, I shall be grateful for any help.

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  • How to minimize total cost of shortest path tree

    - by Michael
    I have a directed acyclic graph with positive edge-weights. It has a single source and a set of targets (vertices furthest from the source). I find the shortest paths from the source to each target. Some of these paths overlap. What I want is a shortest path tree which minimizes the total sum of weights over all edges. For example, consider two of the targets. Given all edge weights equal, if they share a single shortest path for most of their length, then that is preferable to two mostly non-overlapping shortest paths (fewer edges in the tree equals lower overall cost). Another example: two paths are non-overlapping for a small part of their length, with high cost for the non-overlapping paths, but low cost for the long shared path (low combined cost). On the other hand, two paths are non-overlapping for most of their length, with low costs for the non-overlapping paths, but high cost for the short shared path (also, low combined cost). There are many combinations. I want to find solutions with the lowest overall cost, given all the shortest paths from source to target. Does this ring any bells with anyone? Can anyone point me to relevant algorithms or analogous applications? Cheers!

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  • How to skip to next iteration in jQuery.each() util?

    - by Josh
    I'm trying to iterate through an array of elements. jQuery's documentation says: jquery.Each() documentation Returning non-false is the same as a continue statement in a for loop, it will skip immediately to the next iteration. I've tried calling 'return non-false;' and 'non-false;' (sans return) neither of which skip to the next iteration. Instead, they break the loop. What am i missing?

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  • Getting a seg fault, having trouble with classes and variables.

    - by celestialorb
    Ok, so I'm still learning the ropes of C++ here so I apologize if this is a simple mistake. I have this class: class RunFrame : public wxFrame { public: RunFrame(); void OnKey(wxKeyEvent& keyEvent); private: // Configuration variables. const wxString *title; const wxPoint *origin; const wxSize *size; const wxColour *background; const wxColour *foreground; const wxString *placeholder; // Control variables. wxTextCtrl *command; // Event table. DECLARE_EVENT_TABLE() }; ...then in the OnKey method I have this code: void RunFrame::OnKey(wxKeyEvent& keyEvent) { // Take the key and process it. if(WXK_RETURN == keyEvent.GetKeyCode()) { bool empty = command -> IsEmpty(); } // Propogate the event through. keyEvent.Skip(); } ...but my program keeps seg faulting when it reaches the line where I attempt to call the IsEmpty method from the command variable. My question is, "Why?" In the constructor of the RunFrame class I can seemingly call methods for the command variable in the same way I'm doing so in the OnKey method...and it compiles correctly, it just seg faults on me when it attempts to execute that line. Here is the code for the constructor if necessary: RunFrame::RunFrame() : wxFrame(NULL, wxID_ANY, wxT("DEFAULT"), wxDefaultPosition, wxDefaultSize, wxBORDER_NONE) { // Create the styling constants. title = new wxString(wxT("RUN")); origin = new wxPoint(0, 0); size = new wxSize(250, 25); background = new wxColour(33, 33, 33); foreground = new wxColour(255, 255, 255); placeholder = new wxString(wxT("command")); // Set the styling for the frame. this -> SetTitle(*title); this -> SetSize(*size); // Create the panel and attach the TextControl to it. wxPanel *panel = new wxPanel(this, wxID_ANY, *origin, *size, wxBORDER_NONE); // Create the text control and attach it to the panel. command = new wxTextCtrl(panel, wxID_ANY, *placeholder, *origin, *size); // Set the styling for the text control. command -> SetBackgroundColour(*background); command -> SetForegroundColour(*foreground); // Connect the key event to the text control. command -> Connect(wxEVT_CHAR, wxKeyEventHandler(RunFrame::OnKey)); // Set the focus to the command box. command -> SetFocus(); } Thanks in advance for any help you can give! Regards, celestialorb

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  • Data Access from single table in sql server 2005 is too slow

    - by Muhammad Kashif Nadeem
    Following is the script of table. Accessing data from this table is too slow. SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Emails]( [id] [int] IDENTITY(1,1) NOT NULL, [datecreated] [datetime] NULL CONSTRAINT [DF_Emails_datecreated] DEFAULT (getdate()), [UID] [nvarchar](250) COLLATE Latin1_General_CI_AS NULL, [From] [nvarchar](100) COLLATE Latin1_General_CI_AS NULL, [To] [nvarchar](100) COLLATE Latin1_General_CI_AS NULL, [Subject] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [Body] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [HTML] [nvarchar](max) COLLATE Latin1_General_CI_AS NULL, [AttachmentCount] [int] NULL, [Dated] [datetime] NULL ) ON [PRIMARY] Following query takes 50 seconds to fetch data. select id, datecreated, UID, [From], [To], Subject, AttachmentCount, Dated from emails If I include Body and Html in select then time is event worse. indexes are on: id unique clustered From Non unique non clustered To Non unique non clustered Tabls has currently 180000+ records. There might be 100,000 records each month so this will become more slow as time will pass. Does splitting data into two table will solve the problem? What other indexes should be there?

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  • map<string, vector<string>> reassignment of vector value

    - by user2950936
    I am trying to write a program that takes lines from an input file, sorts the lines into 'signatures' for the purpose of combining all words that are anagrams of each other. I have to use a map, storing the 'signatures' as the keys and storing all words that match those signatures into a vector of strings. Afterwards I must print all words that are anagrams of each other on the same line. Here is what I have so far: #include <iostream> #include <string> #include <algorithm> #include <map> #include <fstream> using namespace std; string signature(const string&); void printMap(const map<string, vector<string>>&); int main(){ string w1,sig1; vector<string> data; map<string, vector<string>> anagrams; map<string, vector<string>>::iterator it; ifstream myfile; myfile.open("words.txt"); while(getline(myfile, w1)) { sig1=signature(w1); anagrams[sig1]=data.push_back(w1); //to my understanding this should always work, } //either by inserting a new element/key or //by pushing back the new word into the vector<string> data //variable at index sig1, being told that the assignment operator //cannot be used in this way with these data types myfile.close(); printMap(anagrams); return 0; } string signature(const string& w) { string sig; sig=sort(w.begin(), w.end()); return sig; } void printMap(const map& m) { for(string s : m) { for(int i=0;i<m->second.size();i++) cout << m->second.at(); cout << endl; } } The first explanation is working, didn't know it was that simple! However now my print function is giving me: prob2.cc: In function âvoid printMap(const std::map<std::basic_string<char>, std::vector<std::basic_string<char> > >&)â: prob2.cc:43:36: error: cannot bind âstd::basic_ostream<char>::__ostream_type {aka std::basic_ostream<char>}â lvalue to âstd::basic_ostream<char>&&â In file included from /opt/centos/devtoolset-1.1/root/usr/lib/gcc/x86_64-redhat-linux/4.7.2/../../../../include/c++/4.7.2/iostream:40:0, Tried many variations and they always complain about binding void printMap(const map<string, vector<string>> &mymap) { for(auto &c : mymap) cout << c.first << endl << c.second << endl; }

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  • Make file Linking issue Undefined symbols for architecture x86_64

    - by user1035839
    I am working on getting a few files to link together using my make file and c++ and am getting the following error when running make. g++ -bind_at_load `pkg-config --cflags opencv` -c -o compute_gist.o compute_gist.cpp g++ -bind_at_load `pkg-config --cflags opencv` -c -o gist.o gist.cpp g++ -bind_at_load `pkg-config --cflags opencv` -c -o standalone_image.o standalone_image.cpp g++ -bind_at_load `pkg-config --cflags opencv` -c -o IplImageConverter.o IplImageConverter.cpp g++ -bind_at_load `pkg-config --cflags opencv` -c -o GistCalculator.o GistCalculator.cpp g++ -bind_at_load `pkg-config --cflags opencv` `pkg-config --libs opencv` compute_gist.o gist.o standalone_image.o IplImageConverter.o GistCalculator.o -o rungist Undefined symbols for architecture x86_64: "color_gist_scaletab(color_image_t*, int, int, int const*)", referenced from: _main in compute_gist.o ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status make: *** [rungist] Error 1 My makefile is as follows (Note, I don't need opencv bindings yet, but will be coding in opencv later. CXX = g++ CXXFLAGS = -bind_at_load `pkg-config --cflags opencv` LFLAGS = `pkg-config --libs opencv` SRC = \ compute_gist.cpp \ gist.cpp \ standalone_image.cpp \ IplImageConverter.cpp \ GistCalculator.cpp OBJS = $(SRC:.cpp=.o) rungist: $(OBJS) $(CXX) $(CXXFLAGS) $(LFLAGS) $(OBJS) -o $@ all: rungist clean: rm -rf $(OBJS) rungist The method header is located in gist.h float *color_gist_scaletab(color_image_t *src, int nblocks, int n_scale, const int *n_orientations); And the method is defined in gist.cpp float *color_gist_scaletab(color_image_t *src, int w, int n_scale, const int *n_orientation) { And finally the compute_gist.cpp (main file) #include <stdio.h> #include <stdlib.h> #include <string.h> #include "gist.h" static color_image_t *load_ppm(const char *fname) { FILE *f=fopen(fname,"r"); if(!f) { perror("could not open infile"); exit(1); } int width,height,maxval; if(fscanf(f,"P6 %d %d %d",&width,&height,&maxval)!=3 || maxval!=255) { fprintf(stderr,"Error: input not a raw PPM with maxval 255\n"); exit(1); } fgetc(f); /* eat the newline */ color_image_t *im=color_image_new(width,height); int i; for(i=0;i<width*height;i++) { im->c1[i]=fgetc(f); im->c2[i]=fgetc(f); im->c3[i]=fgetc(f); } fclose(f); return im; } static void usage(void) { fprintf(stderr,"compute_gist options... [infilename]\n" "infile is a PPM raw file\n" "options:\n" "[-nblocks nb] use a grid of nb*nb cells (default 4)\n" "[-orientationsPerScale o_1,..,o_n] use n scales and compute o_i orientations for scale i\n" ); exit(1); } int main(int argc,char **args) { const char *infilename="/dev/stdin"; int nblocks=4; int n_scale=3; int orientations_per_scale[50]={8,8,4}; while(*++args) { const char *a=*args; if(!strcmp(a,"-h")) usage(); else if(!strcmp(a,"-nblocks")) { if(!sscanf(*++args,"%d",&nblocks)) { fprintf(stderr,"could not parse %s argument",a); usage(); } } else if(!strcmp(a,"-orientationsPerScale")) { char *c; n_scale=0; for(c=strtok(*++args,",");c;c=strtok(NULL,",")) { if(!sscanf(c,"%d",&orientations_per_scale[n_scale++])) { fprintf(stderr,"could not parse %s argument",a); usage(); } } } else { infilename=a; } } color_image_t *im=load_ppm(infilename); //Here's the method call -> :( float *desc=color_gist_scaletab(im,nblocks,n_scale,orientations_per_scale); int i; int descsize=0; //compute descriptor size for(i=0;i<n_scale;i++) descsize+=nblocks*nblocks*orientations_per_scale[i]; descsize*=3; // color //print descriptor for(i=0;i<descsize;i++) printf("%.4f ",desc[i]); printf("\n"); free(desc); color_image_delete(im); return 0; } Any help would be greatly appreciated. I hope this is enough info. Let me know if I need to add more.

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  • Why is my NSURLConnection so slow?

    - by Bama91
    I have setup an NSURLConnection using the guidelines in Using NSURLConnection from the Mac OS X Reference Library, creating an NSMutableURLRequest as POST to a PHP script with a custom body to upload 20 MB of data (see code below). Note that the post body is what it is (line breaks and all) to exactly match an existing desktop implementation. When I run this in the iPhone simulator, the post is successful, but takes an order of magnitude longer than if I run the equivalent code locally on my Mac in C++ (20 minutes vs. 20 seconds, respectively). Any ideas why the difference is so dramatic? I understand that the simulator will give different results than the actual device, but I would expect at least similar results. Thanks const NSUInteger kDataSizePOST = 20971520; const NSString* kServerBDC = @"WWW.SOMEURL.COM"; const NSString* kUploadURL = @"http://WWW.SOMEURL.COM/php/test/upload.php"; const NSString* kUploadFilename = @"test.data"; const NSString* kUsername = @"testuser"; const NSString* kHostname = @"testhost"; srandom(time(NULL)); NSMutableData *uniqueData = [[NSMutableData alloc] initWithCapacity:kDataSizePOST]; for (unsigned int i = 0 ; i < kDataSizePOST ; ++i) { u_int32_t randomByte = ((random() % 95) + 32); [uniqueData appendBytes:(void*)&randomByte length:1]; } NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init]; [request setURL:[NSURL URLWithString:kUploadURL]]; [request setHTTPMethod:@"POST"]; NSString *boundary = @"aBcDd"; NSString *contentType = [NSString stringWithFormat:@"multipart/form-data; boundary=%@",boundary]; [request addValue:contentType forHTTPHeaderField: @"Content-Type"]; NSMutableData *postbody = [NSMutableData data]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[uniqueData length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: form-data; name=test; filename=%@", kUploadFilename] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithString:@";\nContent-Type: multipart/mixed;\n\r\n"] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[NSData dataWithData:uniqueData]]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[kUsername length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: inline; name=Username;\n\r\n%@",kUsername] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"--%@\nContent-Size:%d",boundary,[kHostname length]] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\nContent-Disposition: inline; name=Hostname;\n\r\n%@",kHostname] dataUsingEncoding:NSUTF8StringEncoding]]; [postbody appendData:[[NSString stringWithFormat:@"\n--%@--",boundary] dataUsingEncoding:NSUTF8StringEncoding]]; [request setHTTPBody:postbody]; NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self]; if (theConnection) { _receivedData = [[NSMutableData data] retain]; } else { // Inform the user that the connection failed. } [request release]; [uniqueData release];

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  • How to safely operate on parameters in threads, using C++ & Pthreads?

    - by ChrisCphDK
    Hi. I'm having some trouble with a program using pthreads, where occassional crashes occur, that could be related to how the threads operate on data So I have some basic questions about how to program using threads, and memory layout: Assume that a public class function performs some operations on some strings, and returns the result as a string. The prototype of the function could be like this: std::string SomeClass::somefunc(const std::string &strOne, const std::string &strTwo) { //Error checking of strings have been omitted std::string result = strOne.substr(0,5) + strTwo.substr(0,5); return result; } Is it correct to assume that strings, being dynamic, are stored on the heap, but that a reference to the string is allocated on the stack at runtime? Stack: [Some mem addr] pointer address to where the string is on the heap Heap: [Some mem addr] memory allocated for the initial string which may grow or shrink To make the function thread safe, the function is extended with the following mutex (which is declared as private in the "SomeClass") locking: std::string SomeClass::somefunc(const std::string &strOne, const std::string &strTwo) { pthread_mutex_lock(&someclasslock); //Error checking of strings have been omitted std::string result = strOne.substr(0,5) + strTwo.substr(0,5); pthread_mutex_unlock(&someclasslock); return result; } Is this a safe way of locking down the operations being done on the strings (all three), or could a thread be stopped by the scheduler in the following cases, which I'd assume would mess up the intended logic: a. Right after the function is called, and the parameters: strOne & strTwo have been set in the two reference pointers that the function has on the stack, the scheduler takes away processing time for the thread and lets a new thread in, which overwrites the reference pointers to the function, which then again gets stopped by the scheduler, letting the first thread back in? b. Can the same occur with the "result" string: the first string builds the result, unlocks the mutex, but before returning the scheduler lets in another thread which performs all of it's work, overwriting the result etc. Or are the reference parameters / result string being pushed onto the stack while another thread is doing performing it's task? Is the safe / correct way of doing this in threads, and "returning" a result, to pass a reference to a string that will be filled with the result instead: void SomeClass::somefunc(const std::string &strOne, const std::string &strTwo, std::string result) { pthread_mutex_lock(&someclasslock); //Error checking of strings have been omitted result = strOne.substr(0,5) + strTwo.substr(0,5); pthread_mutex_unlock(&someclasslock); } The intended logic is that several objects of the "SomeClass" class creates new threads and passes objects of themselves as parameters, and then calls the function: "someFunc": int SomeClass::startNewThread() { pthread_attr_t attr; pthread_t pThreadID; if(pthread_attr_init(&attr) != 0) return -1; if(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0) return -2; if(pthread_create(&pThreadID, &attr, proxyThreadFunc, this) != 0) return -3; if(pthread_attr_destroy(&attr) != 0) return -4; return 0; } void* proxyThreadFunc(void* someClassObjPtr) { return static_cast<SomeClass*> (someClassObjPtr)->somefunc("long string","long string"); } Sorry for the long description. But I hope the questions and intended purpose is clear, if not let me know and I'll elaborate. Best regards. Chris

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  • What SQL query should I perform to get the result set expected?

    - by texai
    What SQL query should I perform to get the result set expected, giving the first element of the chain (2) as input data, or any of them ? table name: changes +----+---------------+---------------+ | id | new_record_id | old_record_id | +----+---------------+---------------+ | 1| 4| 2| | -- non relevant data -- | | 6| 7| 4| | -- non relevant data -- | | 11| 13| 7| | 12| 14| 13| | -- non relevant data -- | | 31| 20| 14| +----+---------------+---------------+ Result set expected: +--+ | 2| | 4| | 7| |13| |14| |20| +--+ I know I should consider change my data model, but: What if I couldn't? Thank you in advance!

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  • sudo apt-get update problem

    - by Jeon
    I have a problem with sudo apt-get update that I can't seem to fix and It's causing problems with alot of installations I want to do. I run Ubuntu 12.04. Ign http://ftp.availo.se precise InRelease Ign http://ftp.availo.se precise-updates InRelease Ign http://ftp.availo.se precise-backports InRelease Ign http://ftp.availo.se precise-security InRelease Get:1 http://repository.spotify.com stable InRelease [2,979 B] Ign http://ppa.launchpad.net precise InRelease Ign http://extras.ubuntu.com precise InRelease Ign http://archive.canonical.com precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://ppa.launchpad.net precise InRelease Ign http://repository.spotify.com stable InRelease Ign http://ftp.availo.se precise Release.gpg Ign http://ftp.availo.se precise-updates Release.gpg Ign http://ftp.availo.se precise-backports Release.gpg Ign http://repository.spotify.com stable/non-free amd64 Packages/DiffIndex Hit http://ppa.launchpad.net precise Release.gpg Hit http://ppa.launchpad.net precise Release.gpg Hit http://archive.canonical.com precise Release.gpg Hit http://extras.ubuntu.com precise Release.gpg Ign http://ftp.availo.se precise-security Release.gpg Ign http://repository.spotify.com stable/non-free i386 Packages/DiffIndex Ign http://repository.spotify.com stable/non-free TranslationIndex Hit http://ppa.launchpad.net precise Release.gpg Hit http://archive.canonical.com precise Release Hit http://extras.ubuntu.com precise Release Ign http://ftp.availo.se precise Release Ign http://ftp.availo.se precise-updates Release Hit http://ppa.launchpad.net precise Release Hit http://archive.canonical.com precise/partner amd64 Packages Hit http://extras.ubuntu.com precise/main Sources Ign http://ftp.availo.se precise-backports Release Ign http://ftp.availo.se precise-security Release Hit http://ppa.launchpad.net precise Release Hit http://archive.canonical.com precise/partner i386 Packages Ign http://archive.canonical.com precise/partner TranslationIndex Hit http://ppa.launchpad.net precise Release Hit http://extras.ubuntu.com precise/main amd64 Packages Hit http://extras.ubuntu.com precise/main i386 Packages Ign http://ftp.availo.se precise/main TranslationIndex Ign http://ftp.availo.se precise/multiverse TranslationIndex Ign http://ftp.availo.se precise/restricted TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main amd64 Packages Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Ign http://extras.ubuntu.com precise/main TranslationIndex Ign http://ftp.availo.se precise/universe TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main amd64 Packages Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Hit http://ppa.launchpad.net precise/main Sources Hit http://ppa.launchpad.net precise/main amd64 Packages Hit http://ppa.launchpad.net precise/main i386 Packages Ign http://ppa.launchpad.net precise/main TranslationIndex Ign http://ftp.availo.se precise-updates/main TranslationIndex Ign http://ftp.availo.se precise-updates/multiverse TranslationIndex Ign http://ftp.availo.se precise-updates/restricted TranslationIndex Ign http://ftp.availo.se precise-updates/universe TranslationIndex Hit http://repository.spotify.com stable/non-free amd64 Packages Ign http://ftp.availo.se precise-backports/main TranslationIndex Ign http://ftp.availo.se precise-backports/multiverse TranslationIndex Ign http://ftp.availo.se precise-backports/restricted TranslationIndex Ign http://ftp.availo.se precise-backports/universe TranslationIndex Hit http://repository.spotify.com stable/non-free i386 Packages Ign http://archive.canonical.com precise/partner Translation-en_US Ign http://ftp.availo.se precise-security/main TranslationIndex Ign http://ftp.availo.se precise-security/multiverse TranslationIndex Ign http://ftp.availo.se precise-security/restricted TranslationIndex Ign http://ftp.availo.se precise-security/universe TranslationIndex Ign http://repository.spotify.com stable/non-free Translation-en_US Ign http://archive.canonical.com precise/partner Translation-en Ign http://repository.spotify.com stable/non-free Translation-en Ign http://extras.ubuntu.com precise/main Translation-en_US Ign http://extras.ubuntu.com precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Ign http://ppa.launchpad.net precise/main Translation-en_US Ign http://ppa.launchpad.net precise/main Translation-en Err http://ftp.availo.se precise/main Sources 404 Not Found Err http://ftp.availo.se precise/restricted Sources 404 Not Found Err http://ftp.availo.se precise/universe Sources 404 Not Found Err http://ftp.availo.se precise/multiverse Sources 404 Not Found Err http://ftp.availo.se precise/main amd64 Packages 404 Not Found Err http://ftp.availo.se precise/restricted amd64 Packages 404 Not Found Err http://ftp.availo.se precise/universe amd64 Packages 404 Not Found Err http://ftp.availo.se precise/multiverse amd64 Packages 404 Not Found Err http://ftp.availo.se precise/main i386 Packages 404 Not Found Err http://ftp.availo.se precise/restricted i386 Packages 404 Not Found Err http://ftp.availo.se precise/universe i386 Packages 404 Not Found Err http://ftp.availo.se precise/multiverse i386 Packages 404 Not Found Err http://ftp.availo.se precise-updates/main Sources 404 Not Found Err http://ftp.availo.se precise-updates/restricted Sources 404 Not Found Err http://ftp.availo.se precise-updates/universe Sources 404 Not Found Err http://ftp.availo.se precise-updates/multiverse Sources 404 Not Found Err http://ftp.availo.se precise-updates/main amd64 Packages 404 Not Found Err http://ftp.availo.se precise-updates/restricted amd64 Packages 404 Not Found Err http://ftp.availo.se precise-updates/universe amd64 Packages 404 Not Found Err http://ftp.availo.se precise-updates/multiverse amd64 Packages 404 Not Found Err http://ftp.availo.se precise-updates/main i386 Packages 404 Not Found Err http://ftp.availo.se precise-updates/restricted i386 Packages 404 Not Found Err http://ftp.availo.se precise-updates/universe i386 Packages 404 Not Found Err http://ftp.availo.se precise-updates/multiverse i386 Packages 404 Not Found Err http://ftp.availo.se precise-backports/main Sources 404 Not Found Err http://ftp.availo.se precise-backports/restricted Sources 404 Not Found Err http://ftp.availo.se precise-backports/universe Sources 404 Not Found Err http://ftp.availo.se precise-backports/multiverse Sources 404 Not Found Err http://ftp.availo.se precise-backports/main amd64 Packages 404 Not Found Err http://ftp.availo.se precise-backports/restricted amd64 Packages 404 Not Found Err http://ftp.availo.se precise-backports/universe amd64 Packages 404 Not Found Err http://ftp.availo.se precise-backports/multiverse amd64 Packages 404 Not Found Err http://ftp.availo.se precise-backports/main i386 Packages 404 Not Found Err http://ftp.availo.se precise-backports/restricted i386 Packages 404 Not Found Err http://ftp.availo.se precise-backports/universe i386 Packages 404 Not Found Err http://ftp.availo.se precise-backports/multiverse i386 Packages 404 Not Found Err http://ftp.availo.se precise-security/main Sources 404 Not Found Err http://ftp.availo.se precise-security/restricted Sources 404 Not Found Err http://ftp.availo.se precise-security/universe Sources 404 Not Found Err http://ftp.availo.se precise-security/multiverse Sources 404 Not Found Err http://ftp.availo.se precise-security/main amd64 Packages 404 Not Found Err http://ftp.availo.se precise-security/restricted amd64 Packages 404 Not Found Err http://ftp.availo.se precise-security/universe amd64 Packages 404 Not Found Err http://ftp.availo.se precise-security/multiverse amd64 Packages 404 Not Found Err http://ftp.availo.se precise-security/main i386 Packages 404 Not Found Err http://ftp.availo.se precise-security/restricted i386 Packages 404 Not Found Err http://ftp.availo.se precise-security/universe i386 Packages 404 Not Found Err http://ftp.availo.se precise-security/multiverse i386 Packages 404 Not Found Ign http://ftp.availo.se precise/main Translation-en_US Ign http://ftp.availo.se precise/main Translation-en Ign http://ftp.availo.se precise/multiverse Translation-en_US Ign http://ftp.availo.se precise/multiverse Translation-en Ign http://ftp.availo.se precise/restricted Translation-en_US Ign http://ftp.availo.se precise/restricted Translation-en Ign http://ftp.availo.se precise/universe Translation-en_US Ign http://ftp.availo.se precise/universe Translation-en Ign http://ftp.availo.se precise-updates/main Translation-en_US Ign http://ftp.availo.se precise-updates/main Translation-en Ign http://ftp.availo.se precise-updates/multiverse Translation-en_US Ign http://ftp.availo.se precise-updates/multiverse Translation-en Ign http://ftp.availo.se precise-updates/restricted Translation-en_US Ign http://ftp.availo.se precise-updates/restricted Translation-en Ign http://ftp.availo.se precise-updates/universe Translation-en_US Ign http://ftp.availo.se precise-updates/universe Translation-en Ign http://ftp.availo.se precise-backports/main Translation-en_US Ign http://ftp.availo.se precise-backports/main Translation-en Ign http://ftp.availo.se precise-backports/multiverse Translation-en_US Ign http://ftp.availo.se precise-backports/multiverse Translation-en Ign http://ftp.availo.se precise-backports/restricted Translation-en_US Ign http://ftp.availo.se precise-backports/restricted Translation-en Ign http://ftp.availo.se precise-backports/universe Translation-en_US Ign http://ftp.availo.se precise-backports/universe Translation-en Ign http://ftp.availo.se precise-security/main Translation-en_US Ign http://ftp.availo.se precise-security/main Translation-en Ign http://ftp.availo.se precise-security/multiverse Translation-en_US Ign http://ftp.availo.se precise-security/multiverse Translation-en Ign http://ftp.availo.se precise-security/restricted Translation-en_US Ign http://ftp.availo.se precise-security/restricted Translation-en Ign http://ftp.availo.se precise-security/universe Translation-en_US Ign http://ftp.availo.se precise-security/universe Translation-en Fetched 2,979 B in 9s (328 B/s) W: GPG error: http://repository.spotify.com stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 082CCEDF94558F59 W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/main/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/restricted/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/universe/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/multiverse/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/restricted/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/universe/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/multiverse/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/restricted/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/universe/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise/multiverse/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/main/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/restricted/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/universe/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/multiverse/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/restricted/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/universe/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/multiverse/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/main/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/restricted/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/universe/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-updates/multiverse/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/main/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/restricted/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/universe/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/multiverse/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/restricted/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/universe/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/multiverse/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/main/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/restricted/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/universe/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-backports/multiverse/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/main/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/restricted/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/universe/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/multiverse/source/Sources 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/main/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/restricted/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/universe/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/multiverse/binary-amd64/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/main/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/restricted/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/universe/binary-i386/Packages 404 Not Found W: Failed to fetch http://ftp.availo.se/ubuntu/dists/precise-security/multiverse/binary-i386/Packages 404 Not Found E: Some index files failed to download. They have been ignored, or old ones used instead. I would appreciate a fix to this. Thank you for the help.

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  • So…is it a Seek or a Scan?

    - by Paul White
    You’re probably most familiar with the terms ‘Seek’ and ‘Scan’ from the graphical plans produced by SQL Server Management Studio (SSMS).  The image to the left shows the most common ones, with the three types of scan at the top, followed by four types of seek.  You might look to the SSMS tool-tip descriptions to explain the differences between them: Not hugely helpful are they?  Both mention scans and ranges (nothing about seeks) and the Index Seek description implies that it will not scan the index entirely (which isn’t necessarily true). Recall also yesterday’s post where we saw two Clustered Index Seek operations doing very different things.  The first Seek performed 63 single-row seeking operations; and the second performed a ‘Range Scan’ (more on those later in this post).  I hope you agree that those were two very different operations, and perhaps you are wondering why there aren’t different graphical plan icons for Range Scans and Seeks?  I have often wondered about that, and the first person to mention it after yesterday’s post was Erin Stellato (twitter | blog): Before we go on to make sense of all this, let’s look at another example of how SQL Server confusingly mixes the terms ‘Scan’ and ‘Seek’ in different contexts.  The diagram below shows a very simple heap table with two columns, one of which is the non-clustered Primary Key, and the other has a non-unique non-clustered index defined on it.  The right hand side of the diagram shows a simple query, it’s associated query plan, and a couple of extracts from the SSMS tool-tip and Properties windows. Notice the ‘scan direction’ entry in the Properties window snippet.  Is this a seek or a scan?  The different references to Scans and Seeks are even more pronounced in the XML plan output that the graphical plan is based on.  This fragment is what lies behind the single Index Seek icon shown above: You’ll find the same confusing references to Seeks and Scans throughout the product and its documentation. Making Sense of Seeks Let’s forget all about scans for a moment, and think purely about seeks.  Loosely speaking, a seek is the process of navigating an index B-tree to find a particular index record, most often at the leaf level.  A seek starts at the root and navigates down through the levels of the index to find the point of interest: Singleton Lookups The simplest sort of seek predicate performs this traversal to find (at most) a single record.  This is the case when we search for a single value using a unique index and an equality predicate.  It should be readily apparent that this type of search will either find one record, or none at all.  This operation is known as a singleton lookup.  Given the example table from before, the following query is an example of a singleton lookup seek: Sadly, there’s nothing in the graphical plan or XML output to show that this is a singleton lookup – you have to infer it from the fact that this is a single-value equality seek on a unique index.  The other common examples of a singleton lookup are bookmark lookups – both the RID and Key Lookup forms are singleton lookups (an RID lookup finds a single record in a heap from the unique row locator, and a Key Lookup does much the same thing on a clustered table).  If you happen to run your query with STATISTICS IO ON, you will notice that ‘Scan Count’ is always zero for a singleton lookup. Range Scans The other type of seek predicate is a ‘seek plus range scan’, which I will refer to simply as a range scan.  The seek operation makes an initial descent into the index structure to find the first leaf row that qualifies, and then performs a range scan (either backwards or forwards in the index) until it reaches the end of the scan range. The ability of a range scan to proceed in either direction comes about because index pages at the same level are connected by a doubly-linked list – each page has a pointer to the previous page (in logical key order) as well as a pointer to the following page.  The doubly-linked list is represented by the green and red dotted arrows in the index diagram presented earlier.  One subtle (but important) point is that the notion of a ‘forward’ or ‘backward’ scan applies to the logical key order defined when the index was built.  In the present case, the non-clustered primary key index was created as follows: CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col ASC) ) ; Notice that the primary key index specifies an ascending sort order for the single key column.  This means that a forward scan of the index will retrieve keys in ascending order, while a backward scan would retrieve keys in descending key order.  If the index had been created instead on key_col DESC, a forward scan would retrieve keys in descending order, and a backward scan would return keys in ascending order. A range scan seek predicate may have a Start condition, an End condition, or both.  Where one is missing, the scan starts (or ends) at one extreme end of the index, depending on the scan direction.  Some examples might help clarify that: the following diagram shows four queries, each of which performs a single seek against a column holding every integer from 1 to 100 inclusive.  The results from each query are shown in the blue columns, and relevant attributes from the Properties window appear on the right: Query 1 specifies that all key_col values less than 5 should be returned in ascending order.  The query plan achieves this by seeking to the start of the index leaf (there is no explicit starting value) and scanning forward until the End condition (key_col < 5) is no longer satisfied (SQL Server knows it can stop looking as soon as it finds a key_col value that isn’t less than 5 because all later index entries are guaranteed to sort higher). Query 2 asks for key_col values greater than 95, in descending order.  SQL Server returns these results by seeking to the end of the index, and scanning backwards (in descending key order) until it comes across a row that isn’t greater than 95.  Sharp-eyed readers may notice that the end-of-scan condition is shown as a Start range value.  This is a bug in the XML show plan which bubbles up to the Properties window – when a backward scan is performed, the roles of the Start and End values are reversed, but the plan does not reflect that.  Oh well. Query 3 looks for key_col values that are greater than or equal to 10, and less than 15, in ascending order.  This time, SQL Server seeks to the first index record that matches the Start condition (key_col >= 10) and then scans forward through the leaf pages until the End condition (key_col < 15) is no longer met. Query 4 performs much the same sort of operation as Query 3, but requests the output in descending order.  Again, we have to mentally reverse the Start and End conditions because of the bug, but otherwise the process is the same as always: SQL Server finds the highest-sorting record that meets the condition ‘key_col < 25’ and scans backward until ‘key_col >= 20’ is no longer true. One final point to note: seek operations always have the Ordered: True attribute.  This means that the operator always produces rows in a sorted order, either ascending or descending depending on how the index was defined, and whether the scan part of the operation is forward or backward.  You cannot rely on this sort order in your queries of course (you must always specify an ORDER BY clause if order is important) but SQL Server can make use of the sort order internally.  In the four queries above, the query optimizer was able to avoid an explicit Sort operator to honour the ORDER BY clause, for example. Multiple Seek Predicates As we saw yesterday, a single index seek plan operator can contain one or more seek predicates.  These seek predicates can either be all singleton seeks or all range scans – SQL Server does not mix them.  For example, you might expect the following query to contain two seek predicates, a singleton seek to find the single record in the unique index where key_col = 10, and a range scan to find the key_col values between 15 and 20: SELECT key_col FROM dbo.Example WHERE key_col = 10 OR key_col BETWEEN 15 AND 20 ORDER BY key_col ASC ; In fact, SQL Server transforms the singleton seek (key_col = 10) to the equivalent range scan, Start:[key_col >= 10], End:[key_col <= 10].  This allows both range scans to be evaluated by a single seek operator.  To be clear, this query results in two range scans: one from 10 to 10, and one from 15 to 20. Final Thoughts That’s it for today – tomorrow we’ll look at monitoring singleton lookups and range scans, and I’ll show you a seek on a heap table. Yes, a seek.  On a heap.  Not an index! If you would like to run the queries in this post for yourself, there’s a script below.  Thanks for reading! IF OBJECT_ID(N'dbo.Example', N'U') IS NOT NULL BEGIN DROP TABLE dbo.Example; END ; -- Test table is a heap -- Non-clustered primary key on 'key_col' CREATE TABLE dbo.Example ( key_col INTEGER NOT NULL, data INTEGER NOT NULL, CONSTRAINT [PK dbo.Example key_col] PRIMARY KEY NONCLUSTERED (key_col) ) ; -- Non-unique non-clustered index on the 'data' column CREATE NONCLUSTERED INDEX [IX dbo.Example data] ON dbo.Example (data) ; -- Add 100 rows INSERT dbo.Example WITH (TABLOCKX) ( key_col, data ) SELECT key_col = V.number, data = V.number FROM master.dbo.spt_values AS V WHERE V.[type] = N'P' AND V.number BETWEEN 1 AND 100 ; -- ================ -- Singleton lookup -- ================ ; -- Single value equality seek in a unique index -- Scan count = 0 when STATISTIS IO is ON -- Check the XML SHOWPLAN SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col = 32 ; -- =========== -- Range Scans -- =========== ; -- Query 1 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col <= 5 ORDER BY E.key_col ASC ; -- Query 2 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col > 95 ORDER BY E.key_col DESC ; -- Query 3 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col >= 10 AND E.key_col < 15 ORDER BY E.key_col ASC ; -- Query 4 SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col >= 20 AND E.key_col < 25 ORDER BY E.key_col DESC ; -- Final query (singleton + range = 2 range scans) SELECT E.key_col FROM dbo.Example AS E WHERE E.key_col = 10 OR E.key_col BETWEEN 15 AND 20 ORDER BY E.key_col ASC ; -- === TIDY UP === DROP TABLE dbo.Example; © 2011 Paul White email: [email protected] twitter: @SQL_Kiwi

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  • What is wrong with my specular phong shading

    - by Thijser
    I'm sorry if this should be placed on stackoverflow instead however seeing as this is graphics related I was hoping you guys could help me: I'm attempting to write a phong shader and currently working on the specular. I came acros the following formula: base*pow(dot(V,R),shininess) and attempted to implement it (V is the posion of the viewer and R the reflective vector). This gave the following result and code: Vec3Df phongSpecular(const Vec3Df & vertexPos, Vec3Df & normal, const Vec3Df & lightPos, const Vec3Df & cameraPos, unsigned int index) { Vec3Df relativeLightPos=(lightPos-vertexPos); relativeLightPos.normalize(); Vec3Df relativeCameraPos= (cameraPos-vertexPos); relativeCameraPos.normalize(); int DotOfNormalAndLight = Vec3Df::dotProduct(normal,relativeLightPos); Vec3Df reflective =(relativeLightPos-(2*DotOfNormalAndLight*normal))*-1; reflective.normalize(); float phongyness= Vec3Df::dotProduct(reflective,relativeCameraPos); if (phongyness<0){ phongyness=0; } float shininess= Shininess[index]; float speculair = powf(phongyness,shininess); return Ks[index]*speculair; } I'm looking for something more like this:

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  • When does the "Do One Thing" paradigm become harmful?

    - by Petr
    For the sake of argument here's a sample function that prints contents of a given file line-by-line. Version 1: void printFile(const string & filePath) { fstream file(filePath, ios::in); string line; while (file.good()) { getline(file, line); cout << line << endl; } } I know it is recommended that functions do one thing at one level of abstraction. To me, though code above does pretty much one thing and is fairly atomic. Some books (such as Robert C. Martin's Clean Code) seem to suggest breaking the above code into separate functions. Version 2: void printLine(const string & line) { cout << line << endl; } void printLines(fstream & file) { string line; while (file.good()) { getline(file, line); printLine(line); } } void printFile(const string & filePath) { fstream file(filePath, ios::in); printLines(file); } I understand what they want to achieve (open file / read lines / print line), but isn't it a bit of overkill? The original version is simple and in some sense already does one thing - prints a file. The second version will lead to a large number of really small functions which may be far less legible than the first version. Wouldn't it be, in this case, better to have the code at one place? At which point does the "Do One Thing" paradigm become harmful?

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  • Ways to organize interface and implementation in C++

    - by Felix Dombek
    I've seen that there are several different paradigms in C++ concerning what goes into the header file and what to the cpp file. AFAIK, most people, especially those from a C background, do: foo.h class foo { private: int mem; int bar(); public: foo(); foo(const foo&); foo& operator=(foo); ~foo(); } foo.cpp #include foo.h foo::bar() { return mem; } foo::foo() { mem = 42; } foo::foo(const foo& f) { mem = f.mem; } foo::operator=(foo f) { mem = f.mem; } foo::~foo() {} int main(int argc, char *argv[]) { foo f; } However, my lecturers usually teach C++ to beginners like this: foo.h class foo { private: int mem; int bar() { return mem; } public: foo() { mem = 42; } foo(const foo& f) { mem = f.mem; } foo& operator=(foo f) { mem = f.mem; } ~foo() {} } foo.cpp #include foo.h int main(int argc, char* argv[]) { foo f; } // other global helper functions, DLL exports, and whatnot Originally coming from Java, I have also always stuck to this second way for several reasons, such as that I only have to change something in one place if the interface or method names change, and that I like the different indentation of things in classes when I look at their implementation, and that I find names more readable as foo compared to foo::foo. I want to collect pro's and con's for either way. Maybe there are even still other ways? One disadvantage of my way is of course the need for occasional forward declarations.

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