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  • How To Remove People and Objects From Photographs In Photoshop

    - by Eric Z Goodnight
    You might think that it’s a complicated process to remove objects from photographs. But really Photoshop makes it quite simple, even when removing all traces of a person from digital photographs. Read on to see just how easy it is. Photoshop was originally created to be an image editing program, and it excels at it. With hardly any Photoshop experience, any beginner can begin removing objects or people from their photos. Have some friends that photobombed an otherwise great pic? Tell them to say their farewells, because here’s how to get rid of them with Photoshop! Tools for Removing Objects Removing an object is not really “magical” work. Your goal is basically to cover up the information you don’t want in an image with information you do want. In this sample image, we want to remove the cigar smoking man, and leave the geisha. Here’s a couple of the tools that can be useful to work with when attempting this kind of task. Clone Stamp and Pattern Stamp Tool: Samples parts of your image from your background, and allows you to paint into your image with your mouse or stylus. Eraser and Brush Tools: Paint flat colors and shapes, and erase cloned layers of image information. Basic, down and dirty photo editing tools. Pen, Quick Selection, Lasso, and Crop tools: Select, isolate, and remove parts of your image with these selection tools. All useful in their own way. Some, like the pen tool, are nightmarishly tough on beginners. Remove a Person with the Clone Stamp Tool (Video) The video above uses the Clone Stamp tool to sample and paint with the background texture. It’s a simple tool to use, although it can be confusing, possibly counter-intuitive. Here’s some pointers, in addition to the video above. Select shortcut key to choose the Clone tool stamp from the Tools Panel. Always create a copy of your background layer before doing heavy edits by right clicking on the background in your Layers Panel and selecting “Duplicate.” Hold with the Clone Tool selected, and click anywhere in your image to sample that area. When you’re sampling an area, your cursor is “Aligned” with your sample area. When you paint, your sample area moves. You can turn the “Aligned” setting off by clicking the in the Options Panel at the top of your screen if you want. Change your brush size and hardness as shown in the video by right-clicking in your image. Use your lasso to copy and paste pieces of your image in order to cover up any parts that seem appropriate. Photoshop Magic with the “Content-Aware Fill” One of the hallmark features of CS5 is the “Content-Aware Fill.” Content aware fill can be an excellent shortcut to removing objects and even people in Photoshop, but it is somewhat limited, and can get confused. Here’s a basic rundown on how it works. Select an object using your Lasso tool, shortcut key . The Lasso works fine as this selection can be rough. Navigate to Edit > Fill, and select “Content-Aware,” as illustrated above, from the pull-down menu. It’s surprisingly simple. After some processing, Photoshop has done the work of removing the object for you. It takes a few moments, and it is not perfect, so be prepared to touch it up with some Copy-Paste, or some Clone stamp action. Content Aware Fill Has Its Limits Keep in mind that the Content Aware Fill is meant to be used with other techniques in mind. It doesn’t always perform perfectly, but can give you a great starting point. Take this image for instance. It is actually plausible to hide this figure and make this image look like he was never there at all. With a selection made with the Lasso tool, navigate to Edit > Fill and select “Content Aware” again. The result is surprisingly good, but as you can see, worthy of some touch up. With a result like this one, you’ll have to get your hands dirty with copy-paste to create believable lines in the background. With many photographs, Content Aware Fill will simply get confused and give you results you won’t be happy with. Additional Touch Up for Bad Background Textures with the Pattern Stamp Tool For the perfectionist, cleaning up the lumpy looking textures that the Clone Stamp can leave is fairly simple using the Pattern Stamp Tool. Sample an piece of your image with your Marquee Tool, shortcut key . Navigate to Edit > Define Pattern to create a new Pattern from your selection. Click OK to continue. Click and hold down on the Clone Stamp tool in your Tools Panel until you can select the Pattern Stamp Tool. Pick your new pattern from the Options at the top of your screen, in the Options Panel. Then simply right click in your image in order to pick as soft a brush as possible to paint with. Paint into your image until your background is as smooth as you want it to be, making your painted out object more and more invisible. If you get lines from your repeated texture, experiment turning the on and off and paint over them. In addition to this, simple use of the Crop Tool, shortcut , can recompose an image, making it look as if it never had another object in it at all. Combine these techniques to find a method that works best for your images. Have questions or comments concerning Graphics, Photos, Filetypes, or Photoshop? Send your questions to [email protected], and they may be featured in a future How-To Geek Graphics article. Image Credits: Geisha Kyoto Gion by Todd Laracuenta via Wikipedia, used under Creative Commons. Moai Rano raraku by Aurbina, in Public Domain. Chris Young visits Wrigley by TonyTheTiger, via Wikipedia, used under Creative Commons. Latest Features How-To Geek ETC Ask How-To Geek: How Can I Monitor My Bandwidth Usage? Internet Explorer 9 RC Now Available: Here’s the Most Interesting New Stuff Here’s a Super Simple Trick to Defeating Fake Anti-Virus Malware How to Change the Default Application for Android Tasks Stop Believing TV’s Lies: The Real Truth About "Enhancing" Images The How-To Geek Valentine’s Day Gift Guide CyanogenMod Updates; Rolls out Android 2.3 to the Less Fortunate MyPaint is an Open-Source Graphics App for Digital Painters Can the Birds and Pigs Really Be Friends in the End? [Angry Birds Video] Add the 2D Version of the New Unity Interface to Ubuntu 10.10 and 11.04 MightyMintyBoost Is a 3-in-1 Gadget Charger Watson Ties Against Human Jeopardy Opponents

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  • Plan Operator Tuesday round-up

    - by Rob Farley
    Eighteen posts for T-SQL Tuesday #43 this month, discussing Plan Operators. I put them together and made the following clickable plan. It’s 1000px wide, so I hope you have a monitor wide enough. Let me explain this plan for you (people’s names are the links to the articles on their blogs – the same links as in the plan above). It was clearly a SELECT statement. Wayne Sheffield (@dbawayne) wrote about that, so we start with a SELECT physical operator, leveraging the logical operator Wayne Sheffield. The SELECT operator calls the Paul White operator, discussed by Jason Brimhall (@sqlrnnr) in his post. The Paul White operator is quite remarkable, and can consume three streams of data. Let’s look at those streams. The first pulls data from a Table Scan – Boris Hristov (@borishristov)’s post – using parallel threads (Bradley Ball – @sqlballs) that pull the data eagerly through a Table Spool (Oliver Asmus – @oliverasmus). A scalar operation is also performed on it, thanks to Jeffrey Verheul (@devjef)’s Compute Scalar operator. The second stream of data applies Evil (I figured that must mean a procedural TVF, but could’ve been anything), courtesy of Jason Strate (@stratesql). It performs this Evil on the merging of parallel streams (Steve Jones – @way0utwest), which suck data out of a Switch (Paul White – @sql_kiwi). This Switch operator is consuming data from up to four lookups, thanks to Kalen Delaney (@sqlqueen), Rick Krueger (@dataogre), Mickey Stuewe (@sqlmickey) and Kathi Kellenberger (@auntkathi). Unfortunately Kathi’s name is a bit long and has been truncated, just like in real plans. The last stream performs a join of two others via a Nested Loop (Matan Yungman – @matanyungman). One pulls data from a Spool (my post – @rob_farley) populated from a Table Scan (Jon Morisi). The other applies a catchall operator (the catchall is because Tamera Clark (@tameraclark) didn’t specify any particular operator, and a catchall is what gets shown when SSMS doesn’t know what to show. Surprisingly, it’s showing the yellow one, which is about cursors. Hopefully that’s not what Tamera planned, but anyway...) to the output from an Index Seek operator (Sebastian Meine – @sqlity). Lastly, I think everyone put in 110% effort, so that’s what all the operators cost. That didn’t leave anything for me, unfortunately, but that’s okay. Also, because he decided to use the Paul White operator, Jason Brimhall gets 0%, and his 110% was given to Paul’s Switch operator post. I hope you’ve enjoyed this T-SQL Tuesday, and have learned something extra about Plan Operators. Keep your eye out for next month’s one by watching the Twitter Hashtag #tsql2sday, and why not contribute a post to the party? Big thanks to Adam Machanic as usual for starting all this. @rob_farley

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  • SATA drive problems with two SIL RAID cards

    - by Jon Topper
    I've just put a second SiI 3114 SATARaid card in my home server so that I could add another pair of SATA drives and increase my storage space. Annoyingly, it doesn't seem to work: [ 32.816030] ata5: lost interrupt (Status 0x0) [ 32.816072] ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen [ 32.816091] ata5.00: cmd c8/00:08:00:00:00/00:00:00:00:00/e0 tag 0 dma 4096 in [ 32.816094] res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout) [ 32.816101] ata5.00: status: { DRDY } [ 32.816117] ata5: hard resetting link [ 33.136082] ata5: SATA link down (SStatus 0 SControl 0) [ 36.060940] irq 18: nobody cared (try booting with the "irqpoll" option) [ 36.060949] Pid: 0, comm: swapper Not tainted 2.6.31-20-generic #58-Ubuntu [ 36.060954] Call Trace: [ 36.060977] [] ? printk+0x18/0x1c [ 36.060997] [] __report_bad_irq+0x27/0x90 [ 36.061005] [] note_interrupt+0x150/0x190 [ 36.061011] [] handle_fasteoi_irq+0xac/0xd0 [ 36.061023] [] handle_irq+0x18/0x30 [ 36.061029] [] do_IRQ+0x47/0xc0 [ 36.061042] [] ? irq_exit+0x50/0x70 [ 36.061058] [] ? smp_apic_timer_interrupt+0x57/0x90 [ 36.061065] [] common_interrupt+0x30/0x40 [ 36.061075] [] ? native_safe_halt+0x5/0x10 [ 36.061082] [] default_idle+0x46/0xd0 [ 36.061088] [] cpu_idle+0x8c/0xd0 [ 36.061103] [] rest_init+0x55/0x60 [ 36.061111] [] start_kernel+0x2e6/0x2ec [ 36.061117] [] ? unknown_bootoption+0x0/0x19e [ 36.061133] [] i386_start_kernel+0x7c/0x83 [ 36.061137] handlers: [ 36.061139] [] (sil_interrupt+0x0/0xb0) [ 36.061151] Disabling IRQ #18 [ 38.136014] ata5: hard resetting link [ 38.456022] ata5: SATA link down (SStatus 0 SControl 0) [ 43.456013] ata5: hard resetting link [ 43.776022] ata5: SATA link down (SStatus 0 SControl 0) [ 43.776035] ata5.00: disabled [ 43.776055] ata5.00: device reported invalid CHS sector 0 [ 43.776074] sd 4:0:0:0: [sde] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE [ 43.776082] sd 4:0:0:0: [sde] Sense Key : Aborted Command [current] [descriptor] [ 43.776092] Descriptor sense data with sense descriptors (in hex): [ 43.776097] 72 0b 00 00 00 00 00 0c 00 0a 80 00 00 00 00 00 [ 43.776112] 00 00 00 00 [ 43.776118] sd 4:0:0:0: [sde] Add. Sense: No additional sense information [ 43.776127] end_request: I/O error, dev sde, sector 0 [ 43.776136] Buffer I/O error on device sde, logical block 0 [ 43.776170] ata5: EH complete [ 43.776187] ata5.00: detaching (SCSI 4:0:0:0) root@core:~# cat /proc/interrupts CPU0 0: 47 IO-APIC-edge timer 1: 8 IO-APIC-edge i8042 6: 3 IO-APIC-edge floppy 7: 0 IO-APIC-edge parport0 8: 0 IO-APIC-edge rtc0 9: 0 IO-APIC-fasteoi acpi 14: 53069 IO-APIC-edge pata_sis 15: 53004 IO-APIC-edge pata_sis 17: 112265 IO-APIC-fasteoi sata_sil 18: 200002 IO-APIC-fasteoi sata_sil, SiS SI7012 19: 111140 IO-APIC-fasteoi eth0 20: 0 IO-APIC-fasteoi ohci_hcd:usb2 21: 0 IO-APIC-fasteoi ohci_hcd:usb3 23: 0 IO-APIC-fasteoi ehci_hcd:usb1 NMI: 0 Non-maskable interrupts LOC: 6650492 Local timer interrupts SPU: 0 Spurious interrupts CNT: 0 Performance counter interrupts PND: 0 Performance pending work RES: 0 Rescheduling interrupts CAL: 0 Function call interrupts TLB: 0 TLB shootdowns TRM: 0 Thermal event interrupts THR: 0 Threshold APIC interrupts MCE: 0 Machine check exceptions MCP: 160 Machine check polls ERR: 0 MIS: 0 root@core:~# lspci | grep Raid 00:09.0 RAID bus controller: Silicon Image, Inc. SiI 3114 [SATALink/SATARaid] Serial ATA Controller (rev 02) 00:0a.0 RAID bus controller: Silicon Image, Inc. SiI 3114 [SATALink/SATARaid] Serial ATA Controller (rev 02) root@core:~# lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 9.10 Release: 9.10 Codename: karmic root@core:~# uname -a Linux core.topper.me.uk 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 05:23:09 UTC 2010 i686 GNU/Linux I've tried a combination of different kernel options (irqpoll, noapic, noacpi, pci=noapic) all to no avail. Does anyone have any bright ideas about how I can go about making this work? Swapping PCI cards around isn't an option as there are only two slots in this motherboard (an ASRock K7S41GX). The BIOS doesn't look to have too much in the way of configuration options regarding IRQ usage. Plan B is to ditch this server completely and buy a new QNAP for these drives to go in, but I was hoping to avoid doing this right now.

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  • Project Euler 18: (Iron)Python

    - by Ben Griswold
    In my attempt to learn (Iron)Python out in the open, here’s my solution for Project Euler Problem 18.  As always, any feedback is welcome. # Euler 18 # http://projecteuler.net/index.php?section=problems&id=18 # By starting at the top of the triangle below and moving # to adjacent numbers on the row below, the maximum total # from top to bottom is 23. # # 3 # 7 4 # 2 4 6 # 8 5 9 3 # # That is, 3 + 7 + 4 + 9 = 23. # Find the maximum total from top to bottom of the triangle below: # 75 # 95 64 # 17 47 82 # 18 35 87 10 # 20 04 82 47 65 # 19 01 23 75 03 34 # 88 02 77 73 07 63 67 # 99 65 04 28 06 16 70 92 # 41 41 26 56 83 40 80 70 33 # 41 48 72 33 47 32 37 16 94 29 # 53 71 44 65 25 43 91 52 97 51 14 # 70 11 33 28 77 73 17 78 39 68 17 57 # 91 71 52 38 17 14 91 43 58 50 27 29 48 # 63 66 04 68 89 53 67 30 73 16 69 87 40 31 # 04 62 98 27 23 09 70 98 73 93 38 53 60 04 23 # NOTE: As there are only 16384 routes, it is possible to solve # this problem by trying every route. However, Problem 67, is the # same challenge with a triangle containing one-hundred rows; it # cannot be solved by brute force, and requires a clever method! ;o) import time start = time.time() triangle = [ [75], [95, 64], [17, 47, 82], [18, 35, 87, 10], [20, 04, 82, 47, 65], [19, 01, 23, 75, 03, 34], [88, 02, 77, 73, 07, 63, 67], [99, 65, 04, 28, 06, 16, 70, 92], [41, 41, 26, 56, 83, 40, 80, 70, 33], [41, 48, 72, 33, 47, 32, 37, 16, 94, 29], [53, 71, 44, 65, 25, 43, 91, 52, 97, 51, 14], [70, 11, 33, 28, 77, 73, 17, 78, 39, 68, 17, 57], [91, 71, 52, 38, 17, 14, 91, 43, 58, 50, 27, 29, 48], [63, 66, 04, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31], [04, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 04, 23]] # Loop through each row of the triangle starting at the base. for a in range(len(triangle) - 1, -1, -1): for b in range(0, a): # Get the maximum value for adjacent cells in current row. # Update the cell which would be one step prior in the path # with the new total. For example, compare the first two # elements in row 15. Add the max of 04 and 62 to the first # position of row 14.This provides the max total from row 14 # to 15 starting at the first position. Continue to work up # the triangle until the maximum total emerges at the # triangle's apex. triangle [a-1][b] += max(triangle [a][b], triangle [a][b+1]) print triangle [0][0] print "Elapsed Time:", (time.time() - start) * 1000, "millisecs" a=raw_input('Press return to continue')

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  • Scrum and Team Consolidation

    - by John K. Hines
    I’m still working my way through one of the more painful team consolidations of my career.  One thing that’s made it hard was my assumption that the use of Agile methods and Scrum would make everything easy.  Take three teams, make all work visible, track it, and presto: An efficient, functioning software development team. What I’ve come to realize is that the primary benefit of Scrum is that Scrum brings teams closer to their customers.  Frequent meetings, short iterations, and phased deployments are all meant to keep the customer in the loop.  It’s true that as teams become proficient with Scrum they tend to become more efficient.  But I don’t think it’s true that Scrum automatically helps people work together. Instead, Scrum can point out when teams aren’t good at working together.   And it really illustrates when teams, especially teams in sustaining mode, are reacting to their customers instead of innovating with them.  At the moment we’ve inherited a huge backlog of tools, processes, and personalities.  It’s up to us to sort them all out.  Unfortunately, after 7 &frac12; months we’re still sorting. What I’d recommend for any blended team is to look at your current product lifecycles and work on a single lifecycle for all work.  If you can’t objectively come up with one process, that’s a good indication that the new team might not be a good fit for being a single unit (which happens all the time in bigger companies).  Go ahead & self-organize into sub-teams.  Then repeat the process. If you can come up with a single process, tackle each piece and standardize all of them.  Do this as soon as possible, as it can be uncomfortable.  Standardize your requirements gathering and tracking, your exploration and technical analysis, your project planning, development standards, validation and sustaining processes.  Standardize all of it.  Make this your top priority, get it out of the way, and get back to work. Lastly, managers of blended teams should realize what I’m suggesting is a disruptive process.  But you’ve just reorganized the team is already disrupted.   Don’t pull the bandage off slowly and force the team through a prolonged transition phase, lowering their productivity over the long term.  You can role model leadership to your team and drive a true consolidation.  Destroy roadblocks, reassure those on your team who are afraid of change, and push forward to create something efficient and beautiful.  Then use Scrum to reengage your customers in a way that they’ll love. Technorati tags: Scrum Scrum Process

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  • How do I Integrate Production Database Hot Fixes into Shared Database Development model?

    - by TetonSig
    We are using SQL Source Control 3, SQL Compare, SQL Data Compare from RedGate, Mercurial repositories, TeamCity and a set of 4 environments including production. I am working on getting us to a dedicated environment per developer, but for at least the next 6 months we are stuck with a shared model. To summarize our current system, we have a DEV SQL server where developers first make changes/additions. They commit their changes through SQL Source Control to a local hgdev repository. When they execute an hg push to the main repository, TeamCity listens for that and then (among other things) pushes hgdev repository to hgrc. Another TeamCity process listens for that and does a pull from hgrc and deploys the latest to a QA SQL Server where regression and integration tests are run. When those are passed a push from hgrc to hgprod occurs. We do a compare of hgprod to our PREPROD SQL Server and generate deployment/rollback scripts for our production release. Separate from the above we have database Hot Fixes that will need to be applied in between releases. The process there is for our Operations team make changes on the PreProd database, and then after testing, to use SQL Source Control to commit their hot fix changes to hgprod from the PREPROD database, and then do a compare from hgprod to PRODUCTION, create deployment scripts and run them on PRODUCTION. If we were in a dedicated database per developer model, we could simply automatically push hgprod back to hgdev and merge in the hot fix change (through TeamCity monitoring for hgprod checkins) and then developers would pick it up and merge it to their local repository and database periodically. However, given that with a shared model the DEV database itself is the source of all changes, this won't work. Pushing hotfixes back to hgdev will show up in SQL Source Control as being different than DEV SQL Server and therefore we need to overwrite the reposistory with the "change" from the DEV SQL Server. My only workaround so far is to just have OPS assign a developer the hotfix ticket with a script attached and then we run their hotfixes against DEV ourselves to merge them back in. I'm not happy with that solution. Other than working faster to get to dedicated environment, are they other ways to keep this loop going automatically?

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  • nikto probe warning messages

    - by julio
    Hi-- I have a pretty standard VPS running Ubuntu 8.1, Apache 2.2, PHP 5 etc. -- standard Lamp stack. I am using suhosin and have tried my best to plug the obvious stuff, since I'm the only user-- there's no SSH access except via pubkey on a non-standard port, there's no root access by SSH, no FTP server running, iptables is set to discard anything outside of basically port 80 or my SSH port (there's no mail server or anything else). However, I've still been compromised (not badly as far as I can tell) probably by a SQL injection. I've locked down the SQL user (there's only one outside of root, and he's got limited priv, no file etc.) So I ran nikto to see what I'm doing wrong, and there's a list of things I've never seen, and can't find using "find" or any other method I'm aware of. See below: + /autologon.html?10514: Remotely Anywhere 5.10.415 is vulnerable to XSS attacks that can lead to cookie theft or privilege escalation. This is typically found on port 2000. + /servlet/webacc?User.html=noexist: Netware web access may reveal full path of the web server. Apply vendor patch or upgrade. + OSVDB-35878: /modules.php?name=Members_List&letter='%20OR%20pass%20LIKE%20'a%25'/*: PHP Nuke module allows user names and passwords to be viewed. + OSVDB-3092: /sitemap.xml: This gives a nice listing of the site content. + OSVDB-12184: /index.php?=PHPB8B5F2A0-3C92-11d3-A3A9-4C7B08C10000: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F36-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F34-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F35-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-3092: /administrator/: This might be interesting... + OSVDB-3092: /Agent/: This might be interesting... + OSVDB-3092: /includes/: This might be interesting... + OSVDB-3092: /logs/: This might be interesting... + OSVDB-3092: /tmp/: This might be interesting... + ERROR: /servlet/Counter returned an error: error reading HTTP response + OSVDB-3268: /icons/: Directory indexing is enabled: /icons + OSVDB-3268: /images/: Directory indexing is enabled: /images + OSVDB-3299: /forumscalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /forumzcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /htforumcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /vbcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /vbulletincalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-6659: /kCKAowoWuZkKCUPH7Mr675ILd9hFg1lnyc1tWUuEbkYkFCpCdEnCKkkd9L0bY34tIf9l6t2owkUp9nI5PIDmQzMokDbp71QFTZGxdnZhTUIzxVrQhVgwmPYsMK7g34DURzeiy3nyd4ezX5NtUozTGqMkxDrLheQmx4dDYlRx0vKaX41JX40GEMf21TKWxHAZSUxjgXUnIlKav58GZQ5LNAwSAn13l0w<font%20size=50>DEFACED<!--//--: MyWebServer 1.0.2 is vulnerable to HTML injection. Upgrade to a later version. I understand about the trace and index, but what about the vbulletin and autologin? I've searched, and I can't find any files like that on the server. I have no idea about the "MyWebServer" stuff, the PHP Nuke, or the Netware/servlet stuff-- there's nothing really on the server except a pretty standard Joomla site (updated to the latest version). Any help with these messages and/or what I'm doing wrong is very much appreciated.

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  • Craftsmanship Tour: Day 2 Obtiva

    - by Liam McLennan
    I like Chicago. It is a great city for travellers. From the moment I got off the plane at O’Hare everything was easy. I took the train to ‘the Loop’ and walked around the corner to my hotel, Hotel Blake on Dearborn St. Sadly, the elevated train lines in downtown Chicago remind me of ‘Shall We Dance’. Hotel Blake is excellent (except for the breakfast) and the concierge directed me to a pizza place called Lou Malnati's for Chicago style deep-dish pizza. Lou Malnati’s would be a great place to go with a group of friends. I felt strange dining there by myself, but the food and service were excellent. As usual in the United States the portion was so large that I could not finish it, but oh how I tried. Dave Hoover, who invited me to Obtiva for the day, had asked me to arrive at 9:45am. I was up early and had some time to kill so I stopped at the Willis Tower, since it was on my way to the office. Willis Tower is 1,451 feet (442 m) tall and has an observation deck at the top. Around the observation deck are a set of acrylic boxes, protruding from the side of the building. Brave soles can walk out on the perspex and look between their feet all the way down to the street. It is unnerving. Obtiva is a progressive, craftsmanship-focused software development company in downtown Chicago. Dave even wrote a book, Apprenticeship Patterns, that provides a catalogue of patterns to assist aspiring software craftsmen to achieve their goals. I spent the morning working in Obtiva’s software studio, an open xp-style office that houses Obtiva’s in-house development team. For lunch Dave Hoover, Corey Haines, Cory Foy and I went to a local Greek restaurant (not Dancing Zorbas). Dave, Corey and Cory are three smart and motivated guys and I found their ideas enlightening. It was especially great to chat with Corey Haines since he was the inspiration for my craftsmanship tour in the first place. After lunch I recorded a brief interview with Dave. Unfortunately, the battery in my camera went flat so I missed recording some interesting stuff. Interview with Dave Hoover In the evening Obtiva hosted an rspec hackfest with David Chelimsky and others. This was an excellent opportunity to be around some of the very best ruby programmers. At 10pm I went back to my hotel to get some rest before my train north the next morning.

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  • How to pad number with leading zero with C#

    - by Jalpesh P. Vadgama
    Recently I was working with a project where I was in need to format a number in such a way which can apply leading zero for particular format.  So after doing such R and D I have found a great way to apply this leading zero format. I was having need that I need to pad number in 5 digit format. So following is a table in which format I need my leading zero format. 1-> 00001 20->00020 300->00300 4000->04000 50000->5000 So in the above example you can see that 1 will become 00001 and 20 will become 00200 format so on. So to display an integer value in decimal format I have applied interger.Tostring(String) method where I have passed “Dn” as the value of the format parameter, where n represents the minimum length of the string. So if we pass 5 it will have padding up to 5 digits. So let’s create a simple console application and see how its works. Following is a code for that. using System; namespace LeadingZero { class Program { static void Main(string[] args) { int a = 1; int b = 20; int c = 300; int d = 4000; int e = 50000; Console.WriteLine(string.Format("{0}------>{1}",a,a.ToString("D5"))); Console.WriteLine(string.Format("{0}------>{1}", b, b.ToString("D5"))); Console.WriteLine(string.Format("{0}------>{1}", c, c.ToString("D5"))); Console.WriteLine(string.Format("{0}------>{1}", d, d.ToString("D5"))); Console.WriteLine(string.Format("{0}------>{1}", e, e.ToString("D5"))); Console.ReadKey(); } } } As you can see in the above code I have use string.Format function to display value of integer and after using integer value’s  ToString method. Now Let’s run the console application and following is the output as expected. Here you can see the integer number are converted into the exact output that we requires. That’s it you can see it’s very easy. We have written code in nice clean way and without writing any extra code or loop. Hope you liked it. Stay tuned for more.. Till than happy programming.

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  • Keep website and webservices warm with zero coding

    - by oazabir
    If you want to keep your websites or webservices warm and save user from seeing the long warm up time after an application pool recycle, or IIS restart or new code deployment or even windows restart, you can use the tinyget command line tool, that comes with IIS Resource Kit, to hit the site and services and keep them warm. Here’s how: First get tinyget from here. Download and install the IIS 6.0 Resource Kit on some PC. Then copy the tinyget.exe from “c:\program files…\IIS 6.0 ResourceKit\Tools'\tinyget” to the server where your IIS 6.0 or IIS 7 is running. Then create a batch file that will hit the pages and webservices. Something like this: SET TINYGET=C:\Program Files (x86)\IIS Resources\TinyGet\tinyget.exe"%TINYGET%" -srv:dropthings.omaralzabir.com -uri:http://dropthings.omaralzabir.com/ -status:200"%TINYGET%" -srv:dropthings.omaralzabir.com -uri:http://dropthings.omaralzabir.com/WidgetService.asmx?WSDL - status:200 First I am hitting the homepage to keep the webpage warm. Then I am hitting the webservice URL with ?WSDL parameter, which allows ASP.NET to compile the service if not already compiled and walk through all the operations and reflect on them and thus loading all related DLLs into memory and reducing the warmup time when hit. Tinyget gets the servers name or IP in the –srv parameter and then the actual URI in the –uri. I have specified what’s the HTTP response code to expect in –status parameter. It ensures the site is alive and is returning http 200 code. Besides just warming up a site, you can do some load test on the site. Tinyget can run in multiple threads and run loops to hit some URL. You can literally blow up a site with commands like this: "%TINYGET%" -threads:30 -loop:100 -srv:google.com -uri:http://www.google.com/ -status:200 Tinyget is also pretty useful to run automated tests. You can record http posts in a text file and then use it to make http posts to some page. Then you can put matching clause to check for certain string in the output to ensure the correct response is given. Thus with some simple command line commands, you can warm up, do some transactions, validate the site is giving off correct response as well as run a load test to ensure the server performing well. Very cheap way to get a lot done.

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  • How To show document directory save image in thumbnail in cocos2d class

    - by Anil gupta
    I have just implemented multiple photo selection from iphone photo library and i am saving all selected photo in document directory every time as a array, now i want to show all saved images in my class from document directory as a thumbnail, i have tried some logic but my game getting crashing, My code is below. Any help will be appreciate. Thanks in advance. -(id) init { // always call "super" init // Apple recommends to re-assign "self" with the "super" return value if( (self=[super init])) { CCSprite *photoalbumbg = [CCSprite spriteWithFile:@"photoalbumbg.png"]; photoalbumbg.anchorPoint = ccp(0,0); [self addChild:photoalbumbg z:0]; //Background Sound // [[SimpleAudioEngine sharedEngine]playBackgroundMusic:@"Background Music.wav" loop:YES]; CCSprite *photoalbumframe = [CCSprite spriteWithFile:@"photoalbumframe.png"]; photoalbumframe.position = ccp(160,240); [self addChild:photoalbumframe z:2]; CCSprite *frame = [CCSprite spriteWithFile:@"Photo-Frames.png"]; frame.position = ccp(160,270); [self addChild:frame z:1]; /*_____________________________________________________________________________________*/ CCMenuItemImage * upgradebtn = [CCMenuItemImage itemFromNormalImage:@"AlbumUpgrade.png" selectedImage:@"AlbumUpgrade.png" target:self selector:@selector(Upgrade:)]; CCMenu * fMenu = [CCMenu menuWithItems:upgradebtn,nil]; fMenu.position = ccp(200,110); [self addChild:fMenu z:3]; NSError *error; NSFileManager *fM = [NSFileManager defaultManager]; NSString *documentsDirectory = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]; NSLog(@"Documents directory: %@", [fM contentsOfDirectoryAtPath:documentsDirectory error:&error]); NSArray *allfiles = [fM contentsOfDirectoryAtPath :documentsDirectory error:&error]; directoryList = [[NSMutableArray alloc] init]; for(NSString *file in allfiles) { NSString *path = [documentsDirectory stringByAppendingPathComponent:file]; [directoryList addObject:file]; } NSLog(@"array file name value ==== %@", directoryList); CCSprite *temp = [CCSprite spriteWithFile:[directoryList objectAtIndex:0]]; [temp setTextureRect:CGRectMake(160.0f, 240.0f, 50,50)]; // temp.anchorPoint = ccp(0,0); [self addChild:temp z:10]; for(UIImage *file in directoryList) { // NSData *pngData = [NSData dataWithContentsOfFile:file]; // image = [UIImage imageWithData:pngData]; NSLog(@"uiimage = %@",image); // UIImage *image = [UIImage imageWithContentsOfFile:file]; for (int i=1; i<=3; i++) { for (int j=1;j<=3; j++) { CCTexture2D *tex = [[[CCTexture2D alloc] initWithImage:file] autorelease]; CCSprite *selectedimage = [CCSprite spriteWithTexture:tex rect:CGRectMake(0, 0, 67, 66)]; selectedimage.position = ccp(100*i,350*j); [self addChild:selectedimage]; } } } } return self; }

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  • How To Approach 360 Degree Snake

    - by Austin Brunkhorst
    I've recently gotten into XNA and must say I love it. As sort of a hello world game I decided to create the classic game "Snake". The 90 degree version was very simple and easy to implement. But as I try to make a version of it that allows 360 degree rotation using left and right arrows, I've come into sort of a problem. What i'm doing now stems from the 90 degree version: Iterating through each snake body part beginning at the tail, and ending right before the head. This works great when moving every 100 milliseconds. The problem with this is that it makes for a choppy style of gameplay as technically the game progresses at only 6 fps rather than it's potential 60. I would like to move the snake every game loop. But unfortunately because the snake moves at the rate of it's head's size it goes way too fast. This would mean that the head would need to move at a much smaller increment such as (2, 2) in it's direction rather than what I have now (32, 32). Because I've been working on this game off and on for a couple of weeks while managing school I think that I've been thinking too hard on how to accomplish this. It's probably a simple solution, i'm just not catching it. Here's some pseudo code for what I've tried based off of what makes sense to me. I can't really think of another way to do it. for(int i = SnakeLength - 1; i > 0; i--){ current = SnakePart[i], next = SnakePart[i - 1]; current.x = next.x - (current.width * cos(next.angle)); current.y = next.y - (current.height * sin(next.angle)); current.angle = next.angle; } SnakeHead.x += cos(SnakeAngle) * SnakeSpeed; SnakeHead.y += sin(SnakeAngle) * SnakeSpeed; This produces something like this: Code in Action. As you can see each part always stays behind the head and doesn't make a "Trail" effect. A perfect example of what i'm going for can be found here: Data Worm. Not the viewport rotation but the trailing effect of the triangles. Thanks for any help!

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  • Optimizing AES modes on Solaris for Intel Westmere

    - by danx
    Optimizing AES modes on Solaris for Intel Westmere Review AES is a strong method of symmetric (secret-key) encryption. It is a U.S. FIPS-approved cryptographic algorithm (FIPS 197) that operates on 16-byte blocks. AES has been available since 2001 and is widely used. However, AES by itself has a weakness. AES encryption isn't usually used by itself because identical blocks of plaintext are always encrypted into identical blocks of ciphertext. This encryption can be easily attacked with "dictionaries" of common blocks of text and allows one to more-easily discern the content of the unknown cryptotext. This mode of encryption is called "Electronic Code Book" (ECB), because one in theory can keep a "code book" of all known cryptotext and plaintext results to cipher and decipher AES. In practice, a complete "code book" is not practical, even in electronic form, but large dictionaries of common plaintext blocks is still possible. Here's a diagram of encrypting input data using AES ECB mode: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ AESKey-->(AES Encryption) AESKey-->(AES Encryption) | | | | \/ \/ CipherTextOutput CipherTextOutput Block 1 Block 2 What's the solution to the same cleartext input producing the same ciphertext output? The solution is to further process the encrypted or decrypted text in such a way that the same text produces different output. This usually involves an Initialization Vector (IV) and XORing the decrypted or encrypted text. As an example, I'll illustrate CBC mode encryption: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ IV >----->(XOR) +------------->(XOR) +---> . . . . | | | | | | | | \/ | \/ | AESKey-->(AES Encryption) | AESKey-->(AES Encryption) | | | | | | | | | \/ | \/ | CipherTextOutput ------+ CipherTextOutput -------+ Block 1 Block 2 The steps for CBC encryption are: Start with a 16-byte Initialization Vector (IV), choosen randomly. XOR the IV with the first block of input plaintext Encrypt the result with AES using a user-provided key. The result is the first 16-bytes of output cryptotext. Use the cryptotext (instead of the IV) of the previous block to XOR with the next input block of plaintext Another mode besides CBC is Counter Mode (CTR). As with CBC mode, it also starts with a 16-byte IV. However, for subsequent blocks, the IV is just incremented by one. Also, the IV ix XORed with the AES encryption result (not the plain text input). Here's an illustration: Block 1 Block 2 PlainTextInput PlainTextInput | | | | \/ \/ AESKey-->(AES Encryption) AESKey-->(AES Encryption) | | | | \/ \/ IV >----->(XOR) IV + 1 >---->(XOR) IV + 2 ---> . . . . | | | | \/ \/ CipherTextOutput CipherTextOutput Block 1 Block 2 Optimization Which of these modes can be parallelized? ECB encryption/decryption can be parallelized because it does more than plain AES encryption and decryption, as mentioned above. CBC encryption can't be parallelized because it depends on the output of the previous block. However, CBC decryption can be parallelized because all the encrypted blocks are known at the beginning. CTR encryption and decryption can be parallelized because the input to each block is known--it's just the IV incremented by one for each subsequent block. So, in summary, for ECB, CBC, and CTR modes, encryption and decryption can be parallelized with the exception of CBC encryption. How do we parallelize encryption? By interleaving. Usually when reading and writing data there are pipeline "stalls" (idle processor cycles) that result from waiting for memory to be loaded or stored to or from CPU registers. Since the software is written to encrypt/decrypt the next data block where pipeline stalls usually occurs, we can avoid stalls and crypt with fewer cycles. This software processes 4 blocks at a time, which ensures virtually no waiting ("stalling") for reading or writing data in memory. Other Optimizations Besides interleaving, other optimizations performed are Loading the entire key schedule into the 128-bit %xmm registers. This is done once for per 4-block of data (since 4 blocks of data is processed, when present). The following is loaded: the entire "key schedule" (user input key preprocessed for encryption and decryption). This takes 11, 13, or 15 registers, for AES-128, AES-192, and AES-256, respectively The input data is loaded into another %xmm register The same register contains the output result after encrypting/decrypting Using SSSE 4 instructions (AESNI). Besides the aesenc, aesenclast, aesdec, aesdeclast, aeskeygenassist, and aesimc AESNI instructions, Intel has several other instructions that operate on the 128-bit %xmm registers. Some common instructions for encryption are: pxor exclusive or (very useful), movdqu load/store a %xmm register from/to memory, pshufb shuffle bytes for byte swapping, pclmulqdq carry-less multiply for GCM mode Combining AES encryption/decryption with CBC or CTR modes processing. Instead of loading input data twice (once for AES encryption/decryption, and again for modes (CTR or CBC, for example) processing, the input data is loaded once as both AES and modes operations occur at in the same function Performance Everyone likes pretty color charts, so here they are. I ran these on Solaris 11 running on a Piketon Platform system with a 4-core Intel Clarkdale processor @3.20GHz. Clarkdale which is part of the Westmere processor architecture family. The "before" case is Solaris 11, unmodified. Keep in mind that the "before" case already has been optimized with hand-coded Intel AESNI assembly. The "after" case has combined AES-NI and mode instructions, interleaved 4 blocks at-a-time. « For the first table, lower is better (milliseconds). The first table shows the performance improvement using the Solaris encrypt(1) and decrypt(1) CLI commands. I encrypted and decrypted a 1/2 GByte file on /tmp (swap tmpfs). Encryption improved by about 40% and decryption improved by about 80%. AES-128 is slighty faster than AES-256, as expected. The second table shows more detail timings for CBC, CTR, and ECB modes for the 3 AES key sizes and different data lengths. » The results shown are the percentage improvement as shown by an internal PKCS#11 microbenchmark. And keep in mind the previous baseline code already had optimized AESNI assembly! The keysize (AES-128, 192, or 256) makes little difference in relative percentage improvement (although, of course, AES-128 is faster than AES-256). Larger data sizes show better improvement than 128-byte data. Availability This software is in Solaris 11 FCS. It is available in the 64-bit libcrypto library and the "aes" Solaris kernel module. You must be running hardware that supports AESNI (for example, Intel Westmere and Sandy Bridge, microprocessor architectures). The easiest way to determine if AES-NI is available is with the isainfo(1) command. For example, $ isainfo -v 64-bit amd64 applications pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov amd_sysc cx8 tsc fpu 32-bit i386 applications pclmulqdq aes sse4.2 sse4.1 ssse3 popcnt tscp ahf cx16 sse3 sse2 sse fxsr mmx cmov sep cx8 tsc fpu No special configuration or setup is needed to take advantage of this software. Solaris libraries and kernel automatically determine if it's running on AESNI-capable machines and execute the correctly-tuned software for the current microprocessor. Summary Maximum throughput of AES cipher modes can be achieved by combining AES encryption with modes processing, interleaving encryption of 4 blocks at a time, and using Intel's wide 128-bit %xmm registers and instructions. References "Block cipher modes of operation", Wikipedia Good overview of AES modes (ECB, CBC, CTR, etc.) "Advanced Encryption Standard", Wikipedia "Current Modes" describes NIST-approved block cipher modes (ECB,CBC, CFB, OFB, CCM, GCM)

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  • Performance problems loading XML with SSIS, an alternative way!

    - by AtulThakor
    I recently needed to load several thousand XML files into a SQL database, I created an SSIS package which was created as followed: Using a foreach container to loop through a directory and load each file path into a variable, the “Import XML” dataflow would then load each XML file into a SQL table.       Running this, it took approximately 1 second to load each file which seemed a massive amount of time to parse the XML and load the data, speaking to my colleague Martin Croft, he suggested the use of T-SQL Bulk Insert and OpenRowset, so we adjusted the package as followed:     The same foreach container was used but instead the following SQL command was executed (this is an expression):     "INSERT INTO MyTable(FileDate) SELECT   CAST(bulkcolumn AS XML)     FROM OPENROWSET(         BULK         '" + @[User::CurrentFile]  + "',         SINGLE_BLOB ) AS x"     Using this method we managed to load approximately 20 records per second, much faster…for data loading! For what we wanted to achieve this was perfect but I’ll leave you with the following points when making your own decision on which solution you decide to choose!      Openrowset Method Much faster to get the data into SQL You’ll need to parse or create a view over the XML data to allow the data to be more usable(another post on this!) Not able to apply validation/transformation against the data when loading it The SQL Server service account will need permission to the file No schema validation when loading files SSIS Slower (in our case) Schema validation Allows you to apply transformations/joins to the data Permissions should be less of a problem Data can be loaded into the final form through the package When using a schema validation errors can fail the package (I’ll do another post on this)

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  • Implement Negascout Algorithm with stack

    - by Dan
    I'm not familiar with how these stack exchange accounts work so if this is double posting I apologize. I asked the same thing on stackoverflow. I have added an AI routine to a game I am working on using the Negascout algorithm. It works great, but when I set a higher maximum depth it can take a few seconds to complete. The problem is it blocks the main thread, and the framework I am using does not have a way to deal with multi-threading properly across platforms. So I am trying to change this routine from recursively calling itself, to just managing a stack (vector) so that I can progress through the routine at a controlled pace and not lock up the application while the AI is thinking. I am getting hung up on the second recursive call in the loop. It relies on a returned value from the first call, so I don't know how to add these to a stack. My Working c++ Recursive Code: MoveScore abNegascout(vector<vector<char> > &board, int ply, int alpha, int beta, char piece) { if (ply==mMaxPly) { return MoveScore(evaluation.evaluateBoard(board, piece, oppPiece)); } int currentScore; int bestScore = -INFINITY; MoveCoord bestMove; int adaptiveBeta = beta; vector<MoveCoord> moveList = evaluation.genPriorityMoves(board, piece, findValidMove(board, piece, false)); if (moveList.empty()) { return MoveScore(bestScore); } bestMove = moveList[0]; for(int i=0;i<moveList.size();i++) { MoveCoord move = moveList[i]; vector<vector<char> > newBoard; newBoard.insert( newBoard.end(), board.begin(), board.end() ); effectMove(newBoard, piece, move.getRow(), move.getCol()); // First Call ****** MoveScore current = abNegascout(newBoard, ply+1, -adaptiveBeta, -max(alpha,bestScore), oppPiece); currentScore = - current.getScore(); if (currentScore>bestScore){ if (adaptiveBeta == beta || ply>=(mMaxPly-2)){ bestScore = currentScore; bestMove = move; }else { // Second Call ****** current = abNegascout(newBoard, ply+1, -beta, -currentScore, oppPiece); bestScore = - current.getScore(); bestMove = move; } if(bestScore>=beta){ return MoveScore(bestMove,bestScore); } adaptiveBeta = max(alpha, bestScore) + 1; } } return MoveScore(bestMove,bestScore); } If someone can please help by explaining how to get this to work with a simple stack. Example code would be much appreciated. While c++ would be perfect, any language that demonstrates how would be great. Thank You.

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  • WPF TextBlock refresh in real time

    - by TheOnlyBrien
    I'm new to C#, in fact, this is one of the first projects I've tried to start on my own. I am curious why the TextBlock will not refresh with the following code? The WPF window does not even show up when I add the "while" loop to the code. I just want this to have a real time display of the days since I was born. Please help me out or give me constructive direction. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; namespace daysAliveWPF { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DateTime myBirthday = new DateTime(1984, 01, 19); while (true) { TimeSpan daysAlive = DateTime.Now.Subtract(myBirthday); MyTextBlock.Text = daysAlive.TotalDays.ToString(); } } } } Similar code has worked in a Console Window application, so I don't understand what's going on here. Console Application code snip that did work is: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace DisplayRealTime { class Program { static void Main(string[] args) { DateTime myBirthday = new DateTime(1984, 06, 19); while (true) { TimeSpan daysAlive = DateTime.Now.Subtract(myBirthday); Console.Write("\rTotal Days Alive: {0}", daysAlive.TotalDays.ToString(".#####")); } } } } Thank you!

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  • How do you keep code with continuations/callbacks readable?

    - by Heinzi
    Summary: Are there some well-established best-practice patterns that I can follow to keep my code readable in spite of using asynchronous code and callbacks? I'm using a JavaScript library that does a lot of stuff asynchronously and heavily relies on callbacks. It seems that writing a simple "load A, load B, ..." method becomes quite complicated and hard to follow using this pattern. Let me give a (contrived) example. Let's say I want to load a bunch of images (asynchronously) from a remote web server. In C#/async, I'd write something like this: disableStartButton(); foreach (myData in myRepository) { var result = await LoadImageAsync("http://my/server/GetImage?" + myData.Id); if (result.Success) { myData.Image = result.Data; } else { write("error loading Image " + myData.Id); return; } } write("success"); enableStartButton(); The code layout follows the "flow of events": First, the start button is disabled, then the images are loaded (await ensures that the UI stays responsive) and then the start button is enabled again. In JavaScript, using callbacks, I came up with this: disableStartButton(); var count = myRepository.length; function loadImage(i) { if (i >= count) { write("success"); enableStartButton(); return; } myData = myRepository[i]; LoadImageAsync("http://my/server/GetImage?" + myData.Id, function(success, data) { if (success) { myData.Image = data; } else { write("error loading image " + myData.Id); return; } loadImage(i+1); } ); } loadImage(0); I think the drawbacks are obvious: I had to rework the loop into a recursive call, the code that's supposed to be executed in the end is somewhere in the middle of the function, the code starting the download (loadImage(0)) is at the very bottom, and it's generally much harder to read and follow. It's ugly and I don't like it. I'm sure that I'm not the first one to encounter this problem, so my question is: Are there some well-established best-practice patterns that I can follow to keep my code readable in spite of using asynchronous code and callbacks?

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  • Why Is Faulty Behaviour In The .NET Framework Not Fixed?

    - by Alois Kraus
    Here is the scenario: You have a Windows Form Application that calls a method via Invoke or BeginInvoke which throws exceptions. Now you want to find out where the error did occur and how the method has been called. Here is the output we do get when we call Begin/EndInvoke or simply Invoke The actual code that was executed was like this:         private void cInvoke_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Invoke);         }            [MethodImpl(MethodImplOptions.NoInlining)]         void InvokingFunction(CallMode mode)         {             switch (mode)             {                 case CallMode.Invoke:                     this.Invoke(new MethodInvoker(GenerateError));   The faulting method is called GenerateError which does throw a NotImplementedException exception and wraps it in a NotSupportedException.           [MethodImpl(MethodImplOptions.NoInlining)]         void GenerateError()         {             F1();         }           private void F1()         {             try             {                 F2();             }             catch (Exception ex)             {                 throw new NotSupportedException("Outer Exception", ex);             }         }           private void F2()         {            throw new NotImplementedException("Inner Exception");         } It is clear that the method F2 and F1 did actually throw these exceptions but we do not see them in the call stack. If we directly call the InvokingFunction and catch and print the exception we can find out very easily how we did get into this situation. We see methods F1,F2,GenerateError and InvokingFunction directly in the stack trace and we see that actually two exceptions did occur. Here is for comparison what we get from Invoke/EndInvoke System.NotImplementedException: Inner Exception     StackTrace:    at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)     at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)     at WindowsFormsApplication1.AppForm.InvokingFunction(CallMode mode)     at WindowsFormsApplication1.AppForm.cInvoke_Click(Object sender, EventArgs e)     at System.Windows.Forms.Control.OnClick(EventArgs e)     at System.Windows.Forms.Button.OnClick(EventArgs e) The exception message is kept but the stack starts running from our Invoke call and not from the faulting method F2. We have therefore no clue where this exception did occur! The stack starts running at the method MarshaledInvoke because the exception is rethrown with the throw catchedException which resets the stack trace. That is bad but things are even worse because if previously lets say 5 exceptions did occur .NET will return only the first (innermost) exception. That does mean that we do not only loose the original call stack but all other exceptions and all data contained therein as well. It is a pity that MS does know about this and simply closes this issue as not important. Programmers will play a lot more around with threads than before thanks to TPL, PLINQ that do come with .NET 4. Multithreading is hyped quit a lot in the press and everybody wants to use threads. But if the .NET Framework makes it nearly impossible to track down the easiest UI multithreading issue I have a problem with that. The problem has been reported but obviously not been solved. .NET 4 Beta 2 did not have changed that dreaded GetBaseException call in MarshaledInvoke to return only the innermost exception of the complete exception stack. It is really time to fix this. WPF on the other hand does the right thing and wraps the exceptions inside a TargetInvocationException which makes much more sense. But Not everybody uses WPF for its daily work and Windows forms applications will still be used for a long time. Below is the code to repro the issues shown and how the exceptions can be rendered in a meaningful way. The default Exception.ToString implementation generates a hard to interpret stack if several nested exceptions did occur. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; using System.Globalization; using System.Runtime.CompilerServices;   namespace WindowsFormsApplication1 {     public partial class AppForm : Form     {         enum CallMode         {             Direct = 0,             BeginInvoke = 1,             Invoke = 2         };           public AppForm()         {             InitializeComponent();             Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;             Application.ThreadException += new System.Threading.ThreadExceptionEventHandler(Application_ThreadException);         }           void Application_ThreadException(object sender, System.Threading.ThreadExceptionEventArgs e)         {             cOutput.Text = PrintException(e.Exception, 0, null).ToString();         }           private void cDirectUnhandled_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Direct);         }           private void cDirectCall_Click(object sender, EventArgs e)         {             try             {                 InvokingFunction(CallMode.Direct);             }             catch (Exception ex)             {                 cOutput.Text = PrintException(ex, 0, null).ToString();             }         }           private void cInvoke_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.Invoke);         }           private void cBeginInvokeCall_Click(object sender, EventArgs e)         {             InvokingFunction(CallMode.BeginInvoke);         }           [MethodImpl(MethodImplOptions.NoInlining)]         void InvokingFunction(CallMode mode)         {             switch (mode)             {                 case CallMode.Direct:                     GenerateError();                     break;                 case CallMode.Invoke:                     this.Invoke(new MethodInvoker(GenerateError));                     break;                 case CallMode.BeginInvoke:                     IAsyncResult res = this.BeginInvoke(new MethodInvoker(GenerateError));                     this.EndInvoke(res);                     break;             }         }           [MethodImpl(MethodImplOptions.NoInlining)]         void GenerateError()         {             F1();         }           private void F1()         {             try             {                 F2();             }             catch (Exception ex)             {                 throw new NotSupportedException("Outer Exception", ex);             }         }           private void F2()         {            throw new NotImplementedException("Inner Exception");         }           StringBuilder PrintException(Exception ex, int identLevel, StringBuilder sb)         {             StringBuilder builtStr = sb;             if( builtStr == null )                 builtStr = new StringBuilder();               if( ex == null )                 return builtStr;                 WriteLine(builtStr, String.Format("{0}: {1}", ex.GetType().FullName, ex.Message), identLevel);             WriteLine(builtStr, String.Format("StackTrace: {0}", ShortenStack(ex.StackTrace)), identLevel + 1);             builtStr.AppendLine();               return PrintException(ex.InnerException, ++identLevel, builtStr);         }               void WriteLine(StringBuilder sb, string msg, int identLevel)         {             foreach (string trimmedLine in SplitToLines(msg)                                            .Select( (line) => line.Trim()) )             {                 for (int i = 0; i < identLevel; i++)                     sb.Append('\t');                 sb.Append(trimmedLine);                 sb.AppendLine();             }         }           string ShortenStack(string stack)         {             int nonAppFrames = 0;             // Skip stack frames not part of our app but include two foreign frames and skip the rest             // If our stack frame is encountered reset counter to 0             return SplitToLines(stack)                               .Where((line) =>                               {                                   nonAppFrames = line.Contains("WindowsFormsApplication1") ? 0 : nonAppFrames + 1;                                   return nonAppFrames < 3;                               })                              .Select((line) => line)                              .Aggregate("", (current, line) => current + line + Environment.NewLine);         }           static char[] NewLines = Environment.NewLine.ToCharArray();         string[] SplitToLines(string str)         {             return str.Split(NewLines, StringSplitOptions.RemoveEmptyEntries);         }     } }

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  • Simple Mouse Move Event in F# with Winforms

    - by MarkPearl
    This evening I had the pleasure of reading one of ThomasP’s blog posts on first class events. It was an excellent read, and I thought I would make a brief derivative of his post to explore some of the basics. In Thomas’s post he has a form with an ellipse on it that when he clicks on the ellipse it pops up a message box with the button clicked… awesome. Something that got me on the post though was the code similar to the one below… // React to Mouse Move events on the form let evtMessages = frm.MouseMove |> Event.map (fun mi -> mi.Location.ToString()) |> Event.map (sprintf "Hey, you clicked on the ellipse.\nUsing: %s") |> Event.add (MessageBox.Show >> ignore) The MessageBox is a function with a string passed into it. What if I wanted to rather change a mutable value holder instead, how would the syntax go for that? Immediately the thought came to me of anonymous functions. I’ve used them before to do something like this… let HelloPerson personName = "Hello " + personName |> fun(x) -> Console.WriteLine(x) So using the same approach I adapted the event code to instead of showing a Message Box with a string passed in to it, to rather change the forms header. |> Event.map (sprintf "Your mouse position is %s") |> Event.add(fun(x) -> frm.Text <- x) Okay… it looks a bit weird with the –> x <- syntax, but makes sense and works… The next thing I wanted to do was change Thomas’s code sample from having an ellipse, and reacting to the position of the mouse and click, to rather trigger the event whenever the mouse moved. This simple involved removing some filtering code. Finally I wanted the code to work as a FSharp Project without having to run through the F# interactive. To achieve this I just needed to find out how to trigger the window event loop. This can be achieved with the code below… // Program eventloop while frm.Created do Application.DoEvents()   So lets look at the complete code sample… #light open System open System.Drawing open System.Windows.Forms // Create the main form let frm = new Form(ClientSize=Size(600,400)) // React to Mouse Move events on the form let evtMessages = frm.MouseMove |> Event.map (fun mi -> mi.Location.ToString()) |> Event.map (sprintf "Your mouse position is %s") |> Event.add(fun(x) -> frm.Text <- x) // Show the form frm.Show() // Program eventloop while frm.Created do Application.DoEvents()

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  • Atmospheric scattering sky from space artifacts

    - by ollipekka
    I am in the process of implementing atmospheric scattering of a planets from space. I have been using Sean O'Neil's shaders from http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter16.html as a starting point. I have pretty much the same problem related to fCameraAngle except with SkyFromSpace shader as opposed to GroundFromSpace shader as here: http://www.gamedev.net/topic/621187-sean-oneils-atmospheric-scattering/ I get strange artifacts with sky from space shader when not using fCameraAngle = 1 in the inner loop. What is the cause of these artifacts? The artifacts disappear when fCameraAngle is limtied to 1. I also seem to lack the hue that is present in O'Neil's sandbox (http://sponeil.net/downloads.htm) Camera position X=0, Y=0, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. Camera position X=500, Y=500, Z=500. GroundFromSpace on the left, SkyFromSpace on the right. I've found that the camera angle seems to handled very differently depending the source: In the original shaders the camera angle in SkyFromSpaceShader is calculated as: float fCameraAngle = dot(v3Ray, v3SamplePoint) / fHeight; Whereas in ground from space shader the camera angle is calculated as: float fCameraAngle = dot(-v3Ray, v3Pos) / length(v3Pos); However, various sources online tinker with negating the ray. Why is this? Here is a C# Windows.Forms project that demonstrates the problem and that I've used to generate the images: https://github.com/ollipekka/AtmosphericScatteringTest/ Update: I have found out from the ScatterCPU project found on O'Neil's site that the camera ray is negated when the camera is above the point being shaded so that the scattering is calculated from point to the camera. Changing the ray direction indeed does remove artifacts, but introduces other problems as illustrated here: Furthermore, in the ScatterCPU project, O'Neil guards against situations where optical depth for light is less than zero: float fLightDepth = Scale(fLightAngle, fScaleDepth); if (fLightDepth < float.Epsilon) { continue; } As pointed out in the comments, along with these new artifacts this still leaves the question, what is wrong with the images where camera is positioned at 500, 500, 500? It feels like the halo is focused on completely wrong part of the planet. One would expect that the light would be closer to the spot where the sun should hits the planet, rather than where it changes from day to night. The github project has been updated to reflect changes in this update.

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  • grub problem after grub-repair

    - by alireza
    I had two OS,win 7 and Ubuntu, I was working with win and went out of the room and when came back I saw Grub Rescue!!! I booted live and did grub_repaire and it still says multiple active partitions.operating system not found I feel that it can not find the ubuntu hard drive at all! ! ubuntu@ubuntu:/dev$ sudo fdisk -l Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xde771741 Device Boot Start End Blocks Id System /dev/sda1 * 61 61 0 0 Empty /dev/sda2 2048 30146559 15072256 27 Hidden NTFS WinRE /dev/sda3 * 30146560 30351359 102400 7 HPFS/NTFS/exFAT /dev/sda4 30351360 334483299 152065970 7 HPFS/NTFS/exFAT ubuntu@ubuntu:/dev$ ls autofs dvdrw loop4 ppp ram5 shm tty15 tty29 tty42 tty56 ttyS10 ttyS24 uinput vcsa1 block ecryptfs loop5 psaux ram6 snapshot tty16 tty3 tty43 tty57 ttyS11 ttyS25 urandom vcsa2 bsg fb0 loop6 ptmx ram7 snd tty17 tty30 tty44 tty58 ttyS12 ttyS26 usbmon0 vcsa3 btrfs-control fd loop7 pts ram8 sr0 tty18 tty31 tty45 tty59 ttyS13 ttyS27 usbmon1 vcsa4 bus full loop-control ram0 ram9 stderr tty19 tty32 tty46 tty6 ttyS14 ttyS28 usbmon2 vcsa5 cdrom fuse mapper ram1 random stdin tty2 tty33 tty47 tty60 ttyS15 ttyS29 v4l vcsa6 cdrw fw0 mcelog ram10 rfkill stdout tty20 tty34 tty48 tty61 ttyS16 ttyS3 vcs vcsa7 char hpet mei ram11 rtc tty tty21 tty35 tty49 tty62 ttyS17 ttyS30 vcs1 vga_arbiter console input mem ram12 rtc0 tty0 tty22 tty36 tty5 tty63 ttyS18 ttyS31 vcs2 video0 core kmsg net ram13 sda tty1 tty23 tty37 tty50 tty7 ttyS19 ttyS4 vcs3 zero cpu log network_latency ram14 sda2 tty10 tty24 tty38 tty51 tty8 ttyS2 ttyS5 vcs4 cpu_dma_latency loop0 network_throughput ram15 sda3 tty11 tty25 tty39 tty52 tty9 ttyS20 ttyS6 vcs5 disk loop1 null ram2 sda4 tty12 tty26 tty4 tty53 ttyprintk ttyS21 ttyS7 vcs6 dri loop2 oldmem ram3 sg0 tty13 tty27 tty40 tty54 ttyS0 ttyS22 ttyS8 vcs7 dvd loop3 port ram4 sg1 tty14 tty28 tty41 tty55 ttyS1 ttyS23 ttyS9 vcsa ubuntu@ubuntu:/dev$ someone said { Remove the boot flag from sda1, by typing in a terminal: sudo fdisk /dev/sda1 Then press the 'a' key, and 'Enter'. Then press the '1' key, and 'Enter'. Then press the 'w' key, and 'Enter'. } but after grub-repair I got this log: http://paste.ubuntu.com/1371297/ then I try sudo fdisk /dev/sda1 and But It says unable to open /dev/sda1! which is right as sda1 is not in dev folder (look at the picture!) Can anybody help me? I need to work on my windows for the rest of the semester and don't care of my ubuntu. thank you

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  • Nashorn, the rhino in the room

    - by costlow
    Nashorn is a new runtime within JDK 8 that allows developers to run code written in JavaScript and call back and forth with Java. One advantage to the Nashorn scripting engine is that is allows for quick prototyping of functionality or basic shell scripts that use Java libraries. The previous JavaScript runtime, named Rhino, was introduced in JDK 6 (released 2006, end of public updates Feb 2013). Keeping tradition amongst the global developer community, "Nashorn" is the German word for rhino. The Java platform and runtime is an intentional home to many languages beyond the Java language itself. OpenJDK’s Da Vinci Machine helps coordinate work amongst language developers and tool designers and has helped different languages by introducing the Invoke Dynamic instruction in Java 7 (2011), which resulted in two major benefits: speeding up execution of dynamic code, and providing the groundwork for Java 8’s lambda executions. Many of these improvements are discussed at the JVM Language Summit, where language and tool designers get together to discuss experiences and issues related to building these complex components. There are a number of benefits to running JavaScript applications on JDK 8’s Nashorn technology beyond writing scripts quickly: Interoperability with Java and JavaScript libraries. Scripts do not need to be compiled. Fast execution and multi-threading of JavaScript running in Java’s JRE. The ability to remotely debug applications using an IDE like NetBeans, Eclipse, or IntelliJ (instructions on the Nashorn blog). Automatic integration with Java monitoring tools, such as performance, health, and SIEM. In the remainder of this blog post, I will explain how to use Nashorn and the benefit from those features. Nashorn execution environment The Nashorn scripting engine is included in all versions of Java SE 8, both the JDK and the JRE. Unlike Java code, scripts written in nashorn are interpreted and do not need to be compiled before execution. Developers and users can access it in two ways: Users running JavaScript applications can call the binary directly:jre8/bin/jjs This mechanism can also be used in shell scripts by specifying a shebang like #!/usr/bin/jjs Developers can use the API and obtain a ScriptEngine through:ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn"); When using a ScriptEngine, please understand that they execute code. Avoid running untrusted scripts or passing in untrusted/unvalidated inputs. During compilation, consider isolating access to the ScriptEngine and using Type Annotations to only allow @Untainted String arguments. One noteworthy difference between JavaScript executed in or outside of a web browser is that certain objects will not be available. For example when run outside a browser, there is no access to a document object or DOM tree. Other than that, all syntax, semantics, and capabilities are present. Examples of Java and JavaScript The Nashorn script engine allows developers of all experience levels the ability to write and run code that takes advantage of both languages. The specific dialect is ECMAScript 5.1 as identified by the User Guide and its standards definition through ECMA international. In addition to the example below, Benjamin Winterberg has a very well written Java 8 Nashorn Tutorial that provides a large number of code samples in both languages. Basic Operations A basic Hello World application written to run on Nashorn would look like this: #!/usr/bin/jjs print("Hello World"); The first line is a standard script indication, so that Linux or Unix systems can run the script through Nashorn. On Windows where scripts are not as common, you would run the script like: jjs helloWorld.js. Receiving Arguments In order to receive program arguments your jjs invocation needs to use the -scripting flag and a double-dash to separate which arguments are for jjs and which are for the script itself:jjs -scripting print.js -- "This will print" #!/usr/bin/jjs var whatYouSaid = $ARG.length==0 ? "You did not say anything" : $ARG[0] print(whatYouSaid); Interoperability with Java libraries (including 3rd party dependencies) Another goal of Nashorn was to allow for quick scriptable prototypes, allowing access into Java types and any libraries. Resources operate in the context of the script (either in-line with the script or as separate threads) so if you open network sockets and your script terminates, those sockets will be released and available for your next run. Your code can access Java types the same as regular Java classes. The “import statements” are written somewhat differently to accommodate for language. There is a choice of two styles: For standard classes, just name the class: var ServerSocket = java.net.ServerSocket For arrays or other items, use Java.type: var ByteArray = Java.type("byte[]")You could technically do this for all. The same technique will allow your script to use Java types from any library or 3rd party component and quickly prototype items. Building a user interface One major difference between JavaScript inside and outside of a web browser is the availability of a DOM object for rendering views. When run outside of the browser, JavaScript has full control to construct the entire user interface with pre-fabricated UI controls, charts, or components. The example below is a variation from the Nashorn and JavaFX guide to show how items work together. Nashorn has a -fx flag to make the user interface components available. With the example script below, just specify: jjs -fx -scripting fx.js -- "My title" #!/usr/bin/jjs -fx var Button = javafx.scene.control.Button; var StackPane = javafx.scene.layout.StackPane; var Scene = javafx.scene.Scene; var clickCounter=0; $STAGE.title = $ARG.length>0 ? $ARG[0] : "You didn't provide a title"; var button = new Button(); button.text = "Say 'Hello World'"; button.onAction = myFunctionForButtonClicking; var root = new StackPane(); root.children.add(button); $STAGE.scene = new Scene(root, 300, 250); $STAGE.show(); function myFunctionForButtonClicking(){   var text = "Click Counter: " + clickCounter;   button.setText(text);   clickCounter++;   print(text); } For a more advanced post on using Nashorn to build a high-performing UI, see JavaFX with Nashorn Canvas example. Interoperable with frameworks like Node, Backbone, or Facebook React The major benefit of any language is the interoperability gained by people and systems that can read, write, and use it for interactions. Because Nashorn is built for the ECMAScript specification, developers familiar with JavaScript frameworks can write their code and then have system administrators deploy and monitor the applications the same as any other Java application. A number of projects are also running Node applications on Nashorn through Project Avatar and the supported modules. In addition to the previously mentioned Nashorn tutorial, Benjamin has also written a post about Using Backbone.js with Nashorn. To show the multi-language power of the Java Runtime, there is another interesting example that unites Facebook React and Clojure on JDK 8’s Nashorn. Summary Nashorn provides a simple and fast way of executing JavaScript applications and bridging between the best of each language. By making the full range of Java libraries to JavaScript applications, and the quick prototyping style of JavaScript to Java applications, developers are free to work as they see fit. Software Architects and System Administrators can take advantage of one runtime and leverage any work that they have done to tune, monitor, and certify their systems. Additional information is available within: The Nashorn Users’ Guide Java Magazine’s article "Next Generation JavaScript Engine for the JVM." The Nashorn team’s primary blog or a very helpful collection of Nashorn links.

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  • Beware of const members

    - by nmarun
    I happened to learn a new thing about const today and how one needs to be careful with its usage. Let’s say I have a third-party assembly ‘ConstVsReadonlyLib’ with a class named ConstSideEffect.cs: 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 10; 4: public const int EndValue = 20; 5: } In my project, I reference the above assembly as follows: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < ConstSideEffect.EndValue; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } You’ll see values 10 through 19 as expected. Now, let’s say I receive a new version of the ConstVsReadonlyLib. 1: public class ConstSideEffect 2: { 3: public static readonly int StartValue = 5; 4: public const int EndValue = 30; 5: } If I just drop this new assembly in the bin folder and run the application, without rebuilding my console application, my thinking was that the output would be from 5 to 29. Of course I was wrong… if not you’d not be reading this blog. The actual output is from 5 through 19. The reason is due to the behavior of const and readonly members. To begin with, const is the compile-time constant and readonly is a runtime constant. Next, when you compile the code, a compile-time constant member is replaced with the value of the constant in the code. But, the IL generated when you reference a read-only constant, references the readonly variable, not its value. So, the IL version of the Main method, after compilation actually looks something like: 1: static void Main(string[] args) 2: { 3: for (int i = ConstSideEffect.StartValue; i < 20; i++) 4: { 5: Console.WriteLine(i); 6: } 7: Console.ReadLine(); 8: } I’m no expert with this IL thingi, but when I look at the disassembled code of the exe file (using IL Disassembler), I see the following: I see our readonly member still being referenced by the variable name (ConstVsReadonlyLib.ConstSideEffect::StartValue) in line 0001. Then there’s the Console.WriteLine in line 000b and finally, see the value of 20 in line 0017. This, I’m pretty sure is our const member being replaced by its value which marks the upper bound of the ‘for’ loop. Now you know why the output was from 5 through 19. This definitely is a side-effect of having const members and one needs to be aware of it. While we’re here, I’d like to add a few other points about const and readonly members: const is slightly faster, but is less flexible readonly cannot be declared within a method scope const can be used only on primitive types (numbers and strings) Just wanted to share this before going to bed!

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  • Oracle????????????????????????~????????????????????

    - by Yusuke.Yamamoto
    RDBMS ???????·????????????????????????????????????????????????????????????????????????? ????????Oracle ?????????????????????????????????? Oracle Database ???????????????????????????????? ????????????????????? ????Oracle???????????????????????????????????????????????????????????????????????????? ?????????????? Oracle Database ???????????????????????? ??????????????????????????????????2????????????? 1. ??????(Query Transformation) Query Transformation ???????SQL??????????????????SQL????????????????????? Query Transformation ???Predicate Transformation ? Common Sub-expression Elimination (CSE), Order-BY Elimination (OBYE), Outer Join Elimination (OJE), Simple View Meging (SVM), Predicate Move around (PM), Complex View Merging (CVM), Sub-query Unnesting (SU), Join Predicate Push Down (JPPD) ???? OR Expansion, Star Transformation (ST) ????????????? ···???????????????????????????????????????????????????? Predicate Transformation ?????? Transitive Predicate Generation ????????????? ?????????????SQL???deptno ? 10 ????????????????????????????? select e.ename, d.loc from emp e, dept d where e.deptno=d.deptno and e.deptno=10; ???????????????emp ??? deptno=10 ??????????????dept ??? d.deptno=10 ??????????????????? emp ?? deptno=10 ????????????????????emp ?? deptno=10 ??????10???????10? dept ????????????dept ??20???????????????????????10?*20?=200?????(??????????·?????????)? ??SQL?? Transitive Predicate Generation ??????SQL????????????????? select e.ename, d.location from emp e, dept d where e.deptno=d.deptno and e.deptno=10 and d.deptno=10; ^^^^^^^^^^^ ??????dept ?????? deptno=10 ??????????????????????????10?*1?=10(dept.deptno ?unique????)?1/20????????????????1/20????????????????10??????????30???????????????Query Transformation ???????????????????????????? ?:??????????? dept ?? 1-row table ??????dept ?? driving ???(Outer Table)??? emp ?? probe ???(Inner Table)????????????1?*10?=10 ????????????????????????????????????????????????????????1/20????????????? ?????? Query Transformation ??????SQL????????????????????????????????? Transformation ??????????????????????????????????? 2. ????·????(Access Path Analysis) Access Path Analysis ??Query Transformation ??SQL????????????(Access Path)?????????(Join Method)?????(Join Order)?????????? ??????????????????(FTS)?ROWID?????????????????????????????·?????(Nested Loop Join)???????(Hash Join)????/?????(Sort Merge Join)????????????????????????????????????????????????????????????????????????? Oracle Database ????????? Query Transformation ???? Logical Optimizer?Access Path Analysis ???? Physical Optimizer ????????? ??????????????????????????????????????????????????????????????????????????????????????????????????? ????????????????????????????????????????????????????? Oracle Database ????????????????????? "Oracle ????????" ?????????? Sustaining Engineering?? ?(??? ???) ???????????????? Sustaining Engineering ????????????????????????Oracle Database ???????????????????????? ?????????????????????Ruby????????????????????????? Oracle????????????????????????! Oracle????????????? Oracle????????????????????????

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  • Finding the Twins when Implementing Catmull-Clark subdivision using Half-Edge mesh [migrated]

    - by Ailurus
    Note: The description became a little longer than expected. Do you know a readable implementation of this algorithm using this mesh? Please let me know! I'm trying to implement Catmull-Clark subdivision using Matlab (because later on the results have to be compared with some other stuff already implemented in Matlab). First try was with a Vertex-Face mesh, the algorithm works but it is of course not very efficient (since you need neighbouring information for edges and faces). Therefore, I'm now using a Half-Edge mesh (info), see also the paper of Lutz Kettner. Wikipedia link to the idea behind Catmull-Clark SDV: Wiki. My problem lies in finding the Twin HalfEdges, I'm just not sure how to do this. Below I'm describing my thoughts on the implementation, trying to keep it concise. Half-Edge mesh (using indices to Vertices/HalfEdges/Faces): Vertex (x,y,z,Outgoing_HalfEdge) HalfEdge (HeadVertex (or TailVertex, which one should I use), Next, Face, Twin). Face (HalfEdge) To keep it simple for now, assume that every face is a quadrilateral. The actual mesh is a list of Vertices, HalfEdges and Faces. The new mesh will consist of NewVertices, NewHalfEdges and NewFaces, like this (note: Number_... is the number of ...): NumberNewVertices: Number_Faces + Number_HalfEdges/2 + Number_Vertices NumberNewHalfEdges: 4 * 4 * NumberFaces NumberNewfaces: 4 * NumberFaces Catmull-Clark: Find the FacePoint (centroid) of each Face: --> Just average the x,y,z values of the vertices, save as a NewVertex. Find the EdgePoint of each HalfEdge: --> To prevent duplicates (each HalfEdge has a Twin which would result in the same HalfEdge) --> Only calculate EdgePoints of the HalfEdge which has the lowest index of the Pair. Update old Vertices Ok, now all the new Vertices are calculated (however, their Outgoing_HalfEdge is still unknown). Next step to save the new HalfEdges and Faces. This is the part causing me problems! Loop through each old Face, there are 4 new Faces to be created (because of the quadrilateral assumption) First create the 4 new HalfEdges per New Face, starting at the FacePoint to the Edgepoint Next a new HalfEdge from the EdgePoint to an Updated Vertex Another new one from the Updated Vertex to the next EdgePoint Finally the fourth new HalfEdge from the EdgePoint back to the FacePoint. The HeadVertex of each new HalfEdge is known, the Next HalfEdge too. The Face is also known (since it is the new face you're creating!). Only the Twin HalfEdge is unknown, how should I know this? By the way, while looping through the Vertices of the new Face, assign the Outgoing_HalfEdge to the Vertices. This is probably the place to find out which HalfEdge is the Twin. Finally, after the 4 new HalfEdges are created, save the Face with the HalfVertex index the last newly created HalfVertex. I hope this is clear, if needed I can post my (obviously not-yet-finished) Matlab code.

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