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  • help me improve my sse yuv to rgb ssse3 code

    - by David McPaul
    Hello, I am looking to optimise some sse code I wrote for converting yuv to rgb (both planar and packed yuv functions). i am using SSSE3 at the moment but if there are useful functions from later sse versions thats ok. I am mainly interested in how I would work out processor stalls and the like. Anyone know of any tools that do static analysis of sse code? ; ; Copyright (C) 2009-2010 David McPaul ; ; All rights reserved. Distributed under the terms of the MIT License. ; ; A rather unoptimised set of ssse3 yuv to rgb converters ; does 8 pixels per loop ; inputer: ; reads 128 bits of yuv 8 bit data and puts ; the y values converted to 16 bit in xmm0 ; the u values converted to 16 bit and duplicated into xmm1 ; the v values converted to 16 bit and duplicated into xmm2 ; conversion: ; does the yuv to rgb conversion using 16 bit integer and the ; results are placed into the following registers as 8 bit clamped values ; r values in xmm3 ; g values in xmm4 ; b values in xmm5 ; outputer: ; writes out the rgba pixels as 8 bit values with 0 for alpha ; xmm6 used for scratch ; xmm7 used for scratch %macro cglobal 1 global _%1 %define %1 _%1 align 16 %1: %endmacro ; conversion code %macro yuv2rgbsse2 0 ; u = u - 128 ; v = v - 128 ; r = y + v + v >> 2 + v >> 3 + v >> 5 ; g = y - (u >> 2 + u >> 4 + u >> 5) - (v >> 1 + v >> 3 + v >> 4 + v >> 5) ; b = y + u + u >> 1 + u >> 2 + u >> 6 ; subtract 16 from y movdqa xmm7, [Const16] ; loads a constant using data cache (slower on first fetch but then cached) psubsw xmm0,xmm7 ; y = y - 16 ; subtract 128 from u and v movdqa xmm7, [Const128] ; loads a constant using data cache (slower on first fetch but then cached) psubsw xmm1,xmm7 ; u = u - 128 psubsw xmm2,xmm7 ; v = v - 128 ; load r,b with y movdqa xmm3,xmm0 ; r = y pshufd xmm5,xmm0, 0xE4 ; b = y ; r = y + v + v >> 2 + v >> 3 + v >> 5 paddsw xmm3, xmm2 ; add v to r movdqa xmm7, xmm1 ; move u to scratch pshufd xmm6, xmm2, 0xE4 ; move v to scratch psraw xmm6,2 ; divide v by 4 paddsw xmm3, xmm6 ; and add to r psraw xmm6,1 ; divide v by 2 paddsw xmm3, xmm6 ; and add to r psraw xmm6,2 ; divide v by 4 paddsw xmm3, xmm6 ; and add to r ; b = y + u + u >> 1 + u >> 2 + u >> 6 paddsw xmm5, xmm1 ; add u to b psraw xmm7,1 ; divide u by 2 paddsw xmm5, xmm7 ; and add to b psraw xmm7,1 ; divide u by 2 paddsw xmm5, xmm7 ; and add to b psraw xmm7,4 ; divide u by 32 paddsw xmm5, xmm7 ; and add to b ; g = y - u >> 2 - u >> 4 - u >> 5 - v >> 1 - v >> 3 - v >> 4 - v >> 5 movdqa xmm7,xmm2 ; move v to scratch pshufd xmm6,xmm1, 0xE4 ; move u to scratch movdqa xmm4,xmm0 ; g = y psraw xmm6,2 ; divide u by 4 psubsw xmm4,xmm6 ; subtract from g psraw xmm6,2 ; divide u by 4 psubsw xmm4,xmm6 ; subtract from g psraw xmm6,1 ; divide u by 2 psubsw xmm4,xmm6 ; subtract from g psraw xmm7,1 ; divide v by 2 psubsw xmm4,xmm7 ; subtract from g psraw xmm7,2 ; divide v by 4 psubsw xmm4,xmm7 ; subtract from g psraw xmm7,1 ; divide v by 2 psubsw xmm4,xmm7 ; subtract from g psraw xmm7,1 ; divide v by 2 psubsw xmm4,xmm7 ; subtract from g %endmacro ; outputer %macro rgba32sse2output 0 ; clamp values pxor xmm7,xmm7 packuswb xmm3,xmm7 ; clamp to 0,255 and pack R to 8 bit per pixel packuswb xmm4,xmm7 ; clamp to 0,255 and pack G to 8 bit per pixel packuswb xmm5,xmm7 ; clamp to 0,255 and pack B to 8 bit per pixel ; convert to bgra32 packed punpcklbw xmm5,xmm4 ; bgbgbgbgbgbgbgbg movdqa xmm0, xmm5 ; save bg values punpcklbw xmm3,xmm7 ; r0r0r0r0r0r0r0r0 punpcklwd xmm5,xmm3 ; lower half bgr0bgr0bgr0bgr0 punpckhwd xmm0,xmm3 ; upper half bgr0bgr0bgr0bgr0 ; write to output ptr movntdq [edi], xmm5 ; output first 4 pixels bypassing cache movntdq [edi+16], xmm0 ; output second 4 pixels bypassing cache %endmacro SECTION .data align=16 Const16 dw 16 dw 16 dw 16 dw 16 dw 16 dw 16 dw 16 dw 16 Const128 dw 128 dw 128 dw 128 dw 128 dw 128 dw 128 dw 128 dw 128 UMask db 0x01 db 0x80 db 0x01 db 0x80 db 0x05 db 0x80 db 0x05 db 0x80 db 0x09 db 0x80 db 0x09 db 0x80 db 0x0d db 0x80 db 0x0d db 0x80 VMask db 0x03 db 0x80 db 0x03 db 0x80 db 0x07 db 0x80 db 0x07 db 0x80 db 0x0b db 0x80 db 0x0b db 0x80 db 0x0f db 0x80 db 0x0f db 0x80 YMask db 0x00 db 0x80 db 0x02 db 0x80 db 0x04 db 0x80 db 0x06 db 0x80 db 0x08 db 0x80 db 0x0a db 0x80 db 0x0c db 0x80 db 0x0e db 0x80 ; void Convert_YUV422_RGBA32_SSSE3(void *fromPtr, void *toPtr, int width) width equ ebp+16 toPtr equ ebp+12 fromPtr equ ebp+8 ; void Convert_YUV420P_RGBA32_SSSE3(void *fromYPtr, void *fromUPtr, void *fromVPtr, void *toPtr, int width) width1 equ ebp+24 toPtr1 equ ebp+20 fromVPtr equ ebp+16 fromUPtr equ ebp+12 fromYPtr equ ebp+8 SECTION .text align=16 cglobal Convert_YUV422_RGBA32_SSSE3 ; reserve variables push ebp mov ebp, esp push edi push esi push ecx mov esi, [fromPtr] mov edi, [toPtr] mov ecx, [width] ; loop width / 8 times shr ecx,3 test ecx,ecx jng ENDLOOP REPEATLOOP: ; loop over width / 8 ; YUV422 packed inputer movdqa xmm0, [esi] ; should have yuyv yuyv yuyv yuyv pshufd xmm1, xmm0, 0xE4 ; copy to xmm1 movdqa xmm2, xmm0 ; copy to xmm2 ; extract both y giving y0y0 pshufb xmm0, [YMask] ; extract u and duplicate so each u in yuyv becomes u0u0 pshufb xmm1, [UMask] ; extract v and duplicate so each v in yuyv becomes v0v0 pshufb xmm2, [VMask] yuv2rgbsse2 rgba32sse2output ; endloop add edi,32 add esi,16 sub ecx, 1 ; apparently sub is better than dec jnz REPEATLOOP ENDLOOP: ; Cleanup pop ecx pop esi pop edi mov esp, ebp pop ebp ret cglobal Convert_YUV420P_RGBA32_SSSE3 ; reserve variables push ebp mov ebp, esp push edi push esi push ecx push eax push ebx mov esi, [fromYPtr] mov eax, [fromUPtr] mov ebx, [fromVPtr] mov edi, [toPtr1] mov ecx, [width1] ; loop width / 8 times shr ecx,3 test ecx,ecx jng ENDLOOP1 REPEATLOOP1: ; loop over width / 8 ; YUV420 Planar inputer movq xmm0, [esi] ; fetch 8 y values (8 bit) yyyyyyyy00000000 movd xmm1, [eax] ; fetch 4 u values (8 bit) uuuu000000000000 movd xmm2, [ebx] ; fetch 4 v values (8 bit) vvvv000000000000 ; extract y pxor xmm7,xmm7 ; 00000000000000000000000000000000 punpcklbw xmm0,xmm7 ; interleave xmm7 into xmm0 y0y0y0y0y0y0y0y0 ; extract u and duplicate so each becomes 0u0u punpcklbw xmm1,xmm7 ; interleave xmm7 into xmm1 u0u0u0u000000000 punpcklwd xmm1,xmm7 ; interleave again u000u000u000u000 pshuflw xmm1,xmm1, 0xA0 ; copy u values pshufhw xmm1,xmm1, 0xA0 ; to get u0u0 ; extract v punpcklbw xmm2,xmm7 ; interleave xmm7 into xmm1 v0v0v0v000000000 punpcklwd xmm2,xmm7 ; interleave again v000v000v000v000 pshuflw xmm2,xmm2, 0xA0 ; copy v values pshufhw xmm2,xmm2, 0xA0 ; to get v0v0 yuv2rgbsse2 rgba32sse2output ; endloop add edi,32 add esi,8 add eax,4 add ebx,4 sub ecx, 1 ; apparently sub is better than dec jnz REPEATLOOP1 ENDLOOP1: ; Cleanup pop ebx pop eax pop ecx pop esi pop edi mov esp, ebp pop ebp ret SECTION .note.GNU-stack noalloc noexec nowrite progbits

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  • How to optimize this javascript code?

    - by Andrija
    I have a jsp which uses a lot of javascript and it's just not fast enough. I would like to optimize it so first, here's a part of the code: In the jsp I have the initialization: window.onload = function () { formCollection.pageSize.value = "<%= pagingSize%>"; elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> elementsNumber = <%= resultList.size() %>; <%} else { %> elementsNumber = 0; <% } %> contextPath = "<%= request.getContextPath() %>"; } In my js file I have two types of js functions: // gets the first element and sets it's value to all the other; //the selectSingleNode function is used because I use XSLT transformation //to generate the table _setTehJed = function(){ var resultId = formCollection.elements["idTehJedinice_spis_1"].value; var resultText = formCollection.elements["tehnicka_spis_1"].value; if (resultId != ""){ var counter = 1; while (counter<elementsNumber){ counter++; if(formCollection.elements["idTehJedinice_spis_"+counter] != null){ formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } } // sets the elements checkbox to checked or unchecked _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } I've used these tips: http://blogs.msdn.com/b/ie/archive/2006/08/28/728654.aspx http://code.google.com/speed/articles/optimizing-javascript.html but I still think something could be done like defining the functions like this: In the jsp: window.onload = function () { iDom3.DigitalnaArhivaPrihvat.formCollection=document.forms["controller"]; iDom3.DigitalnaArhivaPrihvat.formCollection.pageSize.value = "<%= pagingSize%>"; iDom3.DigitalnaArhivaPrihvat.elemCollection = iDom3.Table.all["spis"].XML.DOM; <% if (resultList != null) { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = <%= resultList.size() %> <%} else { %> iDom3.DigitalnaArhivaPrihvat.elementsNumber = 0; <% } %> } in the js: iDom3.DigitalnaArhivaPrihvat = { formCollection:null, elemCollection:null, elementsNumber:null, _setTehJed : function(){ var resultId = this.formCollection.elements.idTehJedinice_spis_1.value; var resultText = this.formCollection.elements.tehnicka_spis_1.value; if (resultId != ""){ var counter = 1; while (counter<this.elementsNumber){ counter++; if(this.formCollection.elements["idTehJedinice_spis_"+counter] !== null){ this.formCollection.elements["idTehJedinice_spis_"+counter].value=resultId; this.formCollection.elements["tehnicka_spis_"+counter].value=resultText; } var node=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'tehnicka']/title"); node.text=resultText; var node2=this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+counter+"']/data[@col = 'idTehJedinice']/title"); node2.text=resultId; } } }, _SelectCheckRokCuvanja = { all : [], Item : function (oItem, sId) { this.all["spis_"+sId] = oItem.value; if (oItem.checked) { this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "true"); }else{ this.elemCollection.selectSingleNode("/suite/table/rows/row[@id = 'spis_"+sId+"']/data[@col = 'rokCheck']").setAttribute("default", "false"); } } } but the problem is scoping (if I do it like this, the second function does not execute properly). Any suggestions?

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  • Optimize strategies for xml parsing?

    - by Future2020
    I am looking for general optimization tips and guidelines for xml parsing. One of the optimization strategies is of course selecting the "right" parser. A detailed comparison between the available parsers for ios can be found here http://www.raywenderlich.com/553/how-to-chose-the-best-xml-parser-for-your-iphone-project. However, I am currently trying to investigate general guidelines and tips on how to optimize by payloads to increase the performance as possible. This question is similar to (a question I have posted in the context of ios) but I have not got a sufficient answer. So this question is not in the context of any particular programming language.

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  • Do you know any code sharing sites?

    - by jasondavis
    I am always looking to organize and make my resource bookmarks better and easiar to access when I need them. 1 thing I really like is code sharing sites, they let you enter in code and then give you a special link to give a friend or a user on this site even to show then code, This is a very useful tool I believe. So below is my list of code sharing sites, there is 4 on the list and they all have unique features. Some have syntax highlighting for multiple languages, some allow you to save your code as private and only share with the people you give the link to, and some even run the run and output any possible errors. Do you know of any sites like this? if you know of any sites like this for programming code please post it here. http://pastie.org/ http://codepad.org/ http://pastebin.me/ http://jsbin.com/ allows you to auto-insert a javascript library like jquery and test live js code

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  • How do you protect code from leaking outside?

    - by cubex
    Besides open-sourcing your project and legislation, are there ways to prevent, or at least minimize the damages of code leaking outside your company/group? We obviously can't block Internet access (to prevent emailing the code) because programmer's need their references. We also can't block peripheral devices (USB, Firewire, etc.) The code matters most when it has some proprietary algorithms and in-house developed knowledge (as opposed to regular routine code to draw GUIs, connect to databases, etc.), but some applications (like accounting software and CRMs) are just that: complex collections of routine code that are simple to develop in principle, but will take years to write from scratch. This is where leaked code will come in handy to competitors. As far as I see it, preventing leakage relies almost entirely on human process. What do you think? What precautions and measures are you taking? And has code leakage affected you before?

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  • How to Format Code in Research Reports

    - by RoseOfJericho
    I am currently writing a formal research report, and I'll be including code with this report. Question: Is there an accepted way of displaying code in research reports? I'm thinking both in terms of font, spacing, et cetera, and whether the code should be displayed inside the document, or in an appendix. The code will be JavaScript and PHP. None of the sections of code will be more than 25 lines (so they're mere snippets). There will be approx. half a dozen snippets. Each of the snippets will have a couple of paragraphs explaining what is happening in the code, and a discussion on its pros/cons. I have no contact with the body the report will be submitted to, and they have no published guidelines on how to format code (please do not question these points). Any help considered and appreciated.

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  • Simplyfing code with a lot of ifs

    - by user278618
    I have a method which based on the enum, and to be clear at start we have this situation: public void MyMetohd(Somestatus status) { if(status == Somestatus.Enum1) { DoA(); DoB(); DoC(); DoD(); DoE(); } if(status == Somestatus.Enum2) { DoA(); DoB(); DoC(); DoD(); } if(status == Somestatus.Enum3) { DoA(); DoB(); DoC(); } if(status == Somestatus.Enum4) { DoA(); DoB(); } if(status == Somestatus.Enum5) { DoA(); } } How would you optimize this kind of code ( it isn't mine)?

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  • Optimizing PHP code (trying to determine min/max/between case)

    - by Swizzh
    I know this code-bit does not conform very much to best coding practices, and was looking to improve it, any ideas? if ($query['date_min'] != _get_date_today()) $mode_min = true; if ($query['date_max'] != _get_date_today()) $mode_max = true; if ($mode_max && $mode_min) $mode = "between"; elseif ($mode_max && !$mode_min) $mode = "max"; elseif (!$mode_max && $mode_min) $mode = "min"; else return; if ($mode == "min" || $mode == "between") { $command_min = "A"; } if ($mode == "max" || $mode == "between") { $command_max = "B"; } if ($mode == "between") { $command = $command_min . " AND " . $command_max; } else { if ($mode == "min") $command = $command_min; if ($mode == "max") $command = $command_max; } echo $command;

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  • super-space-optimized code

    - by Will
    There are key self-contained algorithms - particularly cryptography-related such as AES, RSA, SHA1 etc - which you can find many implementations of for free on the internet. Some are written to be nice and portable clean C. Some are written to be fast - often with macros, and explicit unrolling. As far as I can tell, none are trying to be especially super-small - so I'm resigned to writing my own - explicitly AES128 decryption and SHA1 for ARM THUMB2. What patterns and tricks can I use to do so? Are there compilers/tools that can roll-up code?

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  • Have I pushed the limits of my current VPS or is there room for optimization?

    - by JRameau
    I am currently on a mediatemple DV server (basic) 512mb dedicated ram, this is a CentOS based VPS with Plesk and Virtuozzo. My experience with it from day 1 has been bad and I only could sooth my server issues with several caching "Band-aids," but my sites are not as small as they were a year ago either so the issues have worsen. I have 3 Drupal installs running on separate (plesk) domains, 1 of those drupal installs is a multisite, that consists of 5-6 sites 2 of those sites are bringing in actual traffic. Those caching "Band-aids" I mentioned are APC, which seemed to help alot initially, and Drupal's Boost, which is considered a poorman's Varnish, it makes all my pages static for anonymous users. Last 30day combined estimate on Google Ananlytics: 90k visitors 260k pageviews. Issue: alot of downtime, I am continually checking if my sites are up, and lately I have been finding it down more than 3 times daily. Restarting Apache will bring it back up, for some time. I have google search every error message and looked up ways to optimize my DV server, and I am beyond stump what is my next move. Is this server bad, have I hit a impossibly low restriction such as the 12mb kernel memory barrier (kmemsize), is it on my end, do I need to optimize some more? *I have provided as much information as I can below, any help or suggestions given will be appreciated Common Error messages I see in the log: [error] (12)Cannot allocate memory: fork: Unable to fork new process [error] make_obcallback: could not import mod_python.apache.\n Traceback (most recent call last): File "/usr/lib/python2.4/site-packages/mod_python/apache.py", line 21, in ? import traceback File "/usr/lib/python2.4/traceback.py", line 3, in ? import linecache ImportError: No module named linecache [error] python_handler: no interpreter callback found. [warn-phpd] mmap cache can't open /var/www/vhosts/***/httpdocs/*** - Too many open files in system (pid ***) [alert] Child 8125 returned a Fatal error... Apache is exiting! [emerg] (43)Identifier removed: couldn't grab the accept mutex [emerg] (22)Invalid argument: couldn't release the accept mutex cat /proc/user_beancounters: Version: 2.5 uid resource held maxheld barrier limit failcnt 41548: kmemsize 4582652 5306699 12288832 13517715 21105036 lockedpages 0 0 600 600 0 privvmpages 38151 42676 229036 249036 0 shmpages 16274 16274 17237 17237 2 dummy 0 0 0 0 0 numproc 43 46 300 300 0 physpages 27260 29528 0 2147483647 0 vmguarpages 0 0 131072 2147483647 0 oomguarpages 27270 29538 131072 2147483647 0 numtcpsock 21 29 300 300 0 numflock 8 8 480 528 0 numpty 1 1 30 30 0 numsiginfo 0 1 1024 1024 0 tcpsndbuf 648440 675272 2867477 4096277 1711499 tcprcvbuf 301620 359716 2867477 4096277 0 othersockbuf 4472 4472 1433738 2662538 0 dgramrcvbuf 0 0 1433738 1433738 0 numothersock 12 12 300 300 0 dcachesize 0 0 2684271 2764800 0 numfile 3447 3496 6300 6300 3872 dummy 0 0 0 0 0 dummy 0 0 0 0 0 dummy 0 0 0 0 0 numiptent 14 14 200 200 0 TOP: (In January the load avg was really high 3-10, I was able to bring it down where it is currently is by giving APC more memory play around with) top - 16:46:07 up 2:13, 1 user, load average: 0.34, 0.20, 0.20 Tasks: 40 total, 2 running, 37 sleeping, 0 stopped, 1 zombie Cpu(s): 0.3% us, 0.1% sy, 0.0% ni, 99.7% id, 0.0% wa, 0.0% hi, 0.0% si Mem: 916144k total, 156668k used, 759476k free, 0k buffers Swap: 0k total, 0k used, 0k free, 0k cached MySQLTuner: (after optimizing every table and repairing any table with overage I got the fragmented count down to 86) [--] Data in MyISAM tables: 285M (Tables: 1105) [!!] Total fragmented tables: 86 [--] Up for: 2h 44m 38s (409K q [41.421 qps], 6K conn, TX: 1B, RX: 174M) [--] Reads / Writes: 79% / 21% [--] Total buffers: 58.0M global + 2.7M per thread (100 max threads) [!!] Query cache prunes per day: 675307 [!!] Temporary tables created on disk: 35% (7K on disk / 20K total)

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  • Getting ROBOCOPY to return a "proper" exit code?

    - by Lasse V. Karlsen
    Is it possible to ask ROBOCOPY to exit with an exit code that indicates success or failure? I am using ROBOCOPY as part of my TeamCity build configurations, and having to add a step to just silence the exit code from ROBOCOPY seems silly to me. Basically, I have added this: EXIT /B 0 to the script that is being run. However, this of course masks any real problems that ROBOCOPY would return. Basically, I would like to have exit codes of 0 for SUCCESS and non-zero for FAILURE instead of the bit-mask that ROBOCOPY returns now. Or, if I can't have that, is there a simple sequence of batch commands that would translate the bit-mask of ROBOCOPY to a similar value?

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  • How to share malicious source code?

    - by darma
    I have a client whose site (not one i developed) is infected by a trojan/malicious code. I have asked him to send me the dirty files in a zip but either gmail or unzipping is blocking them. I've tried text files and word files, and i'm suspecting many different file types will be blocked the same way, either by my mail client, anti-malware software, browser etc. (which is normal). Do you know a way he could share those lines so i can read them and do some research about the malicious source code? An image/screenshot of his text editor would be an idea but the files are long + i'd prefer to be able to copy/paste from them. Thank you!

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  • Cannot use Alt code for Unicode character insertion any more

    - by Bergi
    I've been using the Alt code for the ellipsis, 8230, for some time now, in several applications. A few days ago it stopped working, and & is displayed instead of … when pressing Alt+8+2+3+0 (on numpad). This happened both on my desktop and on my laptop (where I use it with Fn). Both run on 64bit-Win-7 with code page 850, and both might have recently updated Windows and Opera 12. What could be the reason this input method got disabled, and how do I switch it back? Btw, I just found out that Alt+0+1+3+3 does work.

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  • How can I learn to effectively write Pythonic code?

    - by Matt Fenwick
    I'm tired of getting downvoted and/or semi-rude comments on my Python answers, saying things like "this isn't Pythonic" or "that's not the Python way of doing things". To clarify, I'm not tired of getting corrected and downvoted, and I'm not tired of being wrong: I'm tired of feeling like there's a whole field of Python that I know nothing about, and seems to be implicit knowledge of experienced Python programmers. Doing a google search for "Pythonic" reveals a wide range of interpretations. The wikipedia page says: A common neologism in the Python community is pythonic, which can have a wide range of meanings related to program style. To say that code is pythonic is to say that it uses Python idioms well, that it is natural or shows fluency in the language. Likewise, to say of an interface or language feature that it is pythonic is to say that it works well with Python idioms, that its use meshes well with the rest of the language. It also discusses the term "unpythonic": In contrast, a mark of unpythonic code is that it attempts to write C++ (or Lisp, Perl, or Java) code in Python—that is, provides a rough transcription rather than an idiomatic translation of forms from another language. The concept of pythonicity is tightly bound to Python's minimalist philosophy of readability and avoiding the "there's more than one way to do it" approach. Unreadable code or incomprehensible idioms are unpythonic. I suspect one way to learn the Pythonic way is just to program in Python a whole bunch. But I bet I could write a bunch of crap and not improve that much without some guidance, whereas a good resource might speed up the learning process significantly. PEP 8 might be exactly what I'm looking for, or maybe not. I'm not sure; on the one hand it covers a lot of ground, but on the other hand, I feel like it's more suited as a reference for knowledgeable programmers than a tutorial for fresh 'uns. How do I get my foot in the Pythonic/Python way of doing things door?

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  • What is the best approach for inline code comments?

    - by d1egoaz
    We are doing some refactoring to a 20 years old legacy codebase, and I'm having a discussion with my colleague about the comments format in the code (plsql, java). There is no a default format for comments, but in most cases people do something like this in the comment: // date (year, year-month, yyyy-mm-dd, dd/mm/yyyy), (author id, author name, author nickname) and comment the proposed format for future and past comments that I want is: // {yyyy-mm-dd}, unique_author_company_id, comment My colleague says that we only need the comment, and must reformat all past and future comments to this format: // comment My arguments: I say for maintenance reasons, it's important to know when and who did a change (even this information is in the SCM). The code is living, and for that reason has a history. Because without the change dates it's impossible to know when a change was introduced without open the SCM tool and search in the long object history. because the author is very important, a change of authors is more credible than a change of authory Agility reasons, no need to open and navigate through the SCM tool people would be more afraid to change something that someone did 15 years ago, than something that was recently created or changed. etc. My colleague's arguments: The history is in the SCM Developers must not be aware of the history of the code directly in the code Packages gets 15k lines long and unstructured comments make these packages harder to understand What do you think is the best approach? Or do you have a better approach to solve this problem?

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  • How should I describe the process of learning someone else's code? (In an invoicing situation.)

    - by MattyG
    I have a contract to upgrade some in-house software for a large company. The company has requested multiple feature additions and a few bug fixes. This is my first freelance style job. First, I needed to become familiar with how the application worked - I learnt it as if I was a user. Next, I had to learn how the software worked. I started with broad concepts, and then narrowed down into necessary detail before working on each bug fix and feature. At least at the start of the project, it took me a lot longer to learn the existing code than it did to write the additional features. How can I describe the process of learning the existing code on the invoice? (This part of the company usually does things in-house, so doesn't have much experience dealing with software contractors like me, and I fear they may not understand the overhead of learning someone else's code). I don't want to just tack the learning time onto the actual feature upgrade, because in some cases this would make a 'simple task' look like it took me way too long. I want break the invoice into relevant steps, and communicate that I'm charging for the large overhead of learning someone else's code before being able to add my own to it. Is there a standard way of describing this sort of activity when billing for a job?

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  • Datastore performance, my code or the datastore latency

    - by fredrik
    I had for the last month a bit of a problem with a quite basic datastore query. It involves 2 db.Models with one referring to the other with a db.ReferenceProperty. The problem is that according to the admin logs the request takes about 2-4 seconds to complete. I strip it down to a bare form and a list to display the results. The put works fine, but the get accumulates (in my opinion) way to much cpu time. #The get look like this: outputData['items'] = {} labelsData = Label.all() for label in labelsData: labelItem = label.item.name if labelItem not in outputData['items']: outputData['items'][labelItem] = { 'item' : labelItem, 'labels' : [] } outputData['items'][labelItem]['labels'].append(label.text) path = os.path.join(os.path.dirname(__file__), 'index.html') self.response.out.write(template.render(path, outputData)) #And the models: class Item(db.Model): name = db.StringProperty() class Label(db.Model): text = db.StringProperty() lang = db.StringProperty() item = db.ReferenceProperty(Item) I've tried to make it a number of different way ie. instead of ReferenceProperty storing all Label keys in the Item Model as a db.ListProperty. My test data is just 10 rows in Item and 40 in Label. So my questions: Is it a fools errand to try to optimize this since the high cpu usage is due to the problems with the datastore or have I just screwed up somewhere in the code? ..fredrik

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  • Optimize jQuery code

    - by Dannemannen
    Greetings, Just built some stuff with jQuery, everything works perfect(!), but I would like it to be as optimzed as possible.. what small changes can I do to my code? $(document).ready(function() { // hide the indicator, we use it later $(".indicator").hide(); // start the animation of the progressbar $(".fill").animate({ width: "50px",}, 4000, function() { $(".indicator").effect("pulsate", { times:999 }, 2000);}); // notify-me ajax function $(".btn-submit").click(function() { // get the variable email and put it in a new variable var email = $("input#mail").val(); var dataString = 'mail='+email; $.ajax({ type: "POST", url: "/mail.php", data: dataString, dataType: "json", success: function(msg){ // JSON return, lets do some magic if(msg.status == "ok") { $("#response-box").fadeIn("slow").delay(2000).fadeOut("slow"); $("#fade").fadeIn("slow").delay(2000).fadeOut("slow"); $("#response-box .inner").html("<h1>Thank you.</h1>We'll keep in touch!"); $("#mail").val("e.g. [email protected]"); } else { $("#response-box").fadeIn("slow").delay(2000).fadeOut("slow"); $("#fade").fadeIn("slow").delay(2000).fadeOut("slow"); $("#response-box .inner").html("<h1>Oops.</h1>Please try again!"); } } }); //make sure the form doesn't post return false; }); });

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  • NetBeans Java code formatter: logical operators on new line

    - by mizipzor
    My code looks like this: if (firstCondition() && secondCondition()) { // ... code } The default settings for the code formatter in NetBeans wants to put the && on a new line, like this: if (firstCondition() && secondCondition()) { // ... code } The formatter works well so I would just like to find the setting so it doesnt change the code to the latter. Whats the setting called?

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  • gcc optimization? bug? and its practial implication to project

    - by kumar_m_kiran
    Hi All, My questions are divided into three parts Question 1 Consider the below code, #include <iostream> using namespace std; int main( int argc, char *argv[]) { const int v = 50; int i = 0X7FFFFFFF; cout<<(i + v)<<endl; if ( i + v < i ) { cout<<"Number is negative"<<endl; } else { cout<<"Number is positive"<<endl; } return 0; } No specific compiler optimisation options are used or the O's flag is used. It is basic compilation command g++ -o test main.cpp is used to form the executable. The seemingly very simple code, has odd behaviour in SUSE 64 bit OS, gcc version 4.1.2. The expected output is "Number is negative", instead only in SUSE 64 bit OS, the output would be "Number is positive". After some amount of analysis and doing a 'disass' of the code, I find that the compiler optimises in the below format - Since i is same on both sides of comparison, it cannot be changed in the same expression, remove 'i' from the equation. Now, the comparison leads to if ( v < 0 ), where v is a constant positive, So during compilation itself, the else part cout function address is added to the register. No cmp/jmp instructions can be found. I see that the behaviour is only in gcc 4.1.2 SUSE 10. When tried in AIX 5.1/5.3 and HP IA64, the result is as expected. Is the above optimisation valid? Or, is using the overflow mechanism for int not a valid use case? Question 2 Now when I change the conditional statement from if (i + v < i) to if ( (i + v) < i ) even then, the behaviour is same, this atleast I would personally disagree, since additional braces are provided, I expect the compiler to create a temporary built-in type variable and them compare, thus nullify the optimisation. Question 3 Suppose I have a huge code base, an I migrate my compiler version, such bug/optimisation can cause havoc in my system behaviour. Ofcourse from business perspective, it is very ineffective to test all lines of code again just because of compiler upgradation. I think for all practical purpose, these kinds of error are very difficult to catch (during upgradation) and invariably will be leaked to production site. Can anyone suggest any possible way to ensure to ensure that these kind of bug/optimization does not have any impact on my existing system/code base? PS : When the const for v is removed from the code, then optimization is not done by the compiler. I believe, it is perfectly fine to use overflow mechanism to find if the variable is from MAX - 50 value (in my case).

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  • Unit Testing - not testable code converted to testable code

    - by imak
    I have read so many places is that if your code is not test-able that mean code is not well written. So that makes me start writing a code that is test-able and to start using some unit testing framework. With this though I start looking for some example with piece of code that is not testable and gradually converted to a testable code. I find tons of examples on unit testing but if someone can provide an example like above it probably can jump start things for me. TIA

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  • Feedback on Optimizing C# NET Code Block

    - by Brett Powell
    I just spent quite a few hours reading up on TCP servers and my desired protocol I was trying to implement, and finally got everything working great. I noticed the code looks like absolute bollocks (is the the correct usage? Im not a brit) and would like some feedback on optimizing it, mostly for reuse and readability. The packet formats are always int, int, int, string, string. try { BinaryReader reader = new BinaryReader(clientStream); int packetsize = reader.ReadInt32(); int requestid = reader.ReadInt32(); int serverdata = reader.ReadInt32(); Console.WriteLine("Packet Size: {0} RequestID: {1} ServerData: {2}", packetsize, requestid, serverdata); List<byte> str = new List<byte>(); byte nextByte = reader.ReadByte(); while (nextByte != 0) { str.Add(nextByte); nextByte = reader.ReadByte(); } // Password Sent to be Authenticated string string1 = Encoding.UTF8.GetString(str.ToArray()); str.Clear(); nextByte = reader.ReadByte(); while (nextByte != 0) { str.Add(nextByte); nextByte = reader.ReadByte(); } // NULL string string string2 = Encoding.UTF8.GetString(str.ToArray()); Console.WriteLine("String1: {0} String2: {1}", string1, string2); // Reply to Authentication Request MemoryStream stream = new MemoryStream(); BinaryWriter writer = new BinaryWriter(stream); writer.Write((int)(1)); // Packet Size writer.Write((int)(requestid)); // Mirror RequestID if Authenticated, -1 if Failed byte[] buffer = stream.ToArray(); clientStream.Write(buffer, 0, buffer.Length); clientStream.Flush(); } I am going to be dealing with other packet types as well that are formatted the same (int/int/int/str/str), but different values. I could probably create a packet class, but this is a bit outside my scope of knowledge for how to apply it to this scenario. If it makes any difference, this is the Protocol I am implementing. http://developer.valvesoftware.com/wiki/Source_RCON_Protocol

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  • How to train yourself to avoid writing “clever” code?

    - by Dan Abramov
    Do you know that feeling when you just need to show off that new trick with Expressions or generalize three different procedures? This does not have to be on Architecture Astronaut scale and in fact may be helpful but I can't help but notice someone else would implement the same class or package in a more clear, straightforward (and sometimes boring) manner. I noticed I often design programs by oversolving the problem, sometimes deliberately and sometimes out of boredom. In either case, I usually honestly believe my solution is crystal clear and elegant, until I see evidence to the contrary but it's usually too late. There is also a part of me that prefers undocumented assumptions to code duplication, and cleverness to simplicity. What can I do to resist the urge to write “cleverish” code and when should the bell ring that I am Doing It Wrong? The problem is getting even more pushing as I'm now working with a team of experienced developers, and sometimes my attempts at writing smart code seem foolish even to myself after time dispels the illusion of elegance.

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  • Are there code reviews in opensource projects? If so, what tools are used to do this?

    - by monksy
    I know there is a big push for code reviews in commercial development. However, are code reviews used in open source software or is based on trust? If so, then how are they performed? [Is it a delayed commit, "a pre commit environment", is there a tool that allows for the patch to be sent to another dev]? Are there any projects that use code reviews? From my understanding the linux kernel is mostly based around trust of the commitor. MySQL was based on the main author's approval and the performance impact.

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  • Being prepared for a code review as a developer?

    - by Karthik Sreenivasan
    I am looking for some ideas here. I read the article How should code reviews be Carried Out and Code Reviews, what are the advantages? which were very informative but I still need more clarity on the question below. My Question is, Being the target developer, can you suggest some best practices a developer can incorporate before his code is going get reviewed. Currently I practice the following methods PPT for a logical flow Detailed comments. Issue: Even though I have implemented the above practices, they do not help on the review. The problem I faced is, when certain logic is referred, I keep searching for the implementation and the flow and too much time is wasted in the process and I get on people’s nerve. I think a lot of developers would be going through what I am going through as well.

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