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  • Monitoring UDP socket in glib(mm) eats up CPU time

    - by Gyorgy Szekely
    Hi, I have a GTKmm Windows application (built with MinGW) that receives UDP packets (no sending). The socket is native winsock and I use glibmm IOChannel to connect it to the application main loop. The socket is read with recvfrom. My problem is: this setup eats 25% percent CPU time on a 3GHz workstation. Can somebody tell me why? The application is idle in this case, and if I remove the UDP code, CPU usage drops down to almost zero. As the application has to perform some CPU intensive tasks, I could image better ways to spend that 25% Here are some code excerpts: (sorry for the printf's ;) ) /* bind */ void UDPInterface::bindToPort(unsigned short port) { struct sockaddr_in target; WSADATA wsaData; target.sin_family = AF_INET; target.sin_port = htons(port); target.sin_addr.s_addr = 0; if ( WSAStartup ( 0x0202, &wsaData ) ) { printf("WSAStartup failed!\n"); exit(0); // :) WSACleanup(); } sock = socket( AF_INET, SOCK_DGRAM, 0 ); if (sock == INVALID_SOCKET) { printf("invalid socket!\n"); exit(0); } if (bind(sock,(struct sockaddr*) &target, sizeof(struct sockaddr_in) ) == SOCKET_ERROR) { printf("failed to bind to port!\n"); exit(0); } printf("[UDPInterface::bindToPort] listening on port %i\n", port); } /* read */ bool UDPInterface::UDPEvent(Glib::IOCondition io_condition) { recvfrom(sock, (char*)buf, BUF_SIZE*4, 0, NULL, NULL); /* process packet... */ } /* glibmm connect */ Glib::RefPtr channel = Glib::IOChannel::create_from_win32_socket(udp.sock); Glib::signal_io().connect( sigc::mem_fun(udp, &UDPInterface::UDPEvent), channel, Glib::IO_IN ); I've read here in some other question, and also in glib docs (g_io_channel_win32_new_socket()) that the socket is put into nonblocking mode, and it's "a side-effect of the implementation and unavoidable". Does this explain the CPU effect, it's not clear to me? Whether or not I use glib to access the socket or call recvfrom() directly doesn't seem to make much difference, since CPU is used up before any packet arrives and the read handler gets invoked. Also glibmm docs state that it's ok to call recvfrom() even if the socket is polled (Glib::IOChannel::create_from_win32_socket()) I've tried compiling the program with -pg and created a per function cpu usage report with gprof. This wasn't usefull because the time is not spent in my program, but in some external glib/glibmm dll.

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  • ORMs and Constructors

    - by Harper Shelby
    I'm looking over .NET ORM implementations, and I have a major burning question - are there any .NET ORM implemenations that don't require public properties for every field in the database? When I see examples like this, a little bell goes off in my head. I firmly believe in encapsulation, and being forced to open the kimono of my objects just to make them work nicely with persistence frameworks gives me the heebie-jeebies. Is this sort of accessibility required in all ORMs out there? If not, please point me to examples of those that don't need it!

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  • How do I plot more than one series using qplot?

    - by celenius
    I'm trying to understand how to have more than one series on a plot, using the following data. Year <- c('1950', '1960', '1970', '1980') Bus <- c(10,20,30,40) Bus.sd <- c(1.1, 2.2, 3.3, 4.4) Car <- c(20, 20, 40, 40) Car.sd <- c(1.1, 2.2, 3.3, 4.4) sample_data = data.frame(Year, Bus, Bus.sd, Car, Car.sd) qplot(Year, Bus, data=sample_data, geom="pointrange", ymin = Bus - Bus.sd/2, ymax = Bus + Bus.sd/2) For example, using the above data, how do I show both sample_data$Bus and sample_data$Car on the same plot in different colors? What I tried doing was: p <- qplot(...) then p <- p + qplot(...) where I replicated the previous line, but this gave me an error. I don't fully understand how AES works. I have studied the ggplot2 examples, but have difficulty understanding the relevant examples here.

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  • Calling a function that has 'Activity' as an argument.

    - by Andrew
    I have stripped down my functions for simplicity: public static int countLines(String fileName, Activity activity) throws IOException { BufferedReader in = new BufferedReader(new InputStreamReader(activity.getAssets().open(fileName))); return 3; } I am calling it from here: private CharSequence RandomRead() throws IOException { int numberLines = countLines("data.txt", ??????); return "Success" } In the call to countLines("data.txt", ??????), what do I put as the argument for the Activity? I've Googled all night and I can find no examples of an actual call to a function where Activity is an argument. (Lots of examples actually using 'activity', but no calls to the example functions). Thanks!

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  • Magento Design Patterns

    - by JonB
    Magento, IMHO, represents a PHP system that is built on well thought-out coding principles - reuseable design patterns being one of them. In terms of an example of a PHP system, I think it can be considered pretty cutting edge and therefore worth considering from an architectural point of view. As I understand it, there are many design patterns that are available to the OOP developer. Seeing such patterns being put to use in an open-source system such as Magento allows a developer to view examples of such patterns in real use and in situ, rather than in examples that can sometimes be rather achedemic, and even a little misleading. As such, I am wondering what patterns, other than the ones I have listed below, Magento programmers have used when developing for Magento. As a note, I understand that some of these patterns are in place as a consequence of being built on the Zend Framework, MVC / Front Controller being a couple of them, The obvious ones are: Factory: $product = Mage::getModel('catalog/product'); Singleton: $category = Mage::getSingleton('catalog/session'); Registry: $currentCategory = Mage::registry('current_category');

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  • Where to find xmoov port to C#? (to make Http Pseudo Streaming from c# app)

    - by Ole Jak
    So I found this beautifull script for FLV video format Http Pseudo Streaming but in is in PHP ( found on http://stream.xmoov.com/ ) So does any one know opensource translations or can translate such PHP code into C#? <?php /* xmoov-php 1.0 Development version 0.9.3 beta by: Eric Lorenzo Benjamin jr. webmaster (AT) xmoov (DOT) com originally inspired by Stefan Richter at flashcomguru.com bandwidth limiting by Terry streamingflvcom (AT) dedicatedmanagers (DOT) com This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. For more information, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ For the full license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/legalcode or send a letter to Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 94105, USA. */ // SCRIPT CONFIGURATION //------------------------------------------------------------------------------------------ // MEDIA PATH // // you can configure these settings to point to video files outside the public html folder. //------------------------------------------------------------------------------------------ // points to server root define('XMOOV_PATH_ROOT', ''); // points to the folder containing the video files. define('XMOOV_PATH_FILES', 'video/'); //------------------------------------------------------------------------------------------ // SCRIPT BEHAVIOR //------------------------------------------------------------------------------------------ //set to TRUE to use bandwidth limiting. define('XMOOV_CONF_LIMIT_BANDWIDTH', TRUE); //set to FALSE to prohibit caching of video files. define('XMOOV_CONF_ALLOW_FILE_CACHE', FALSE); //------------------------------------------------------------------------------------------ // BANDWIDTH SETTINGS // // these settings are only needed when using bandwidth limiting. // // bandwidth is limited my sending a limited amount of video data(XMOOV_BW_PACKET_SIZE), // in specified time intervals(XMOOV_BW_PACKET_INTERVAL). // avoid time intervals over 1.5 seconds for best results. // // you can also control bandwidth limiting via http command using your video player. // the function getBandwidthLimit($part) holds three preconfigured presets(low, mid, high), // which can be changed to meet your needs //------------------------------------------------------------------------------------------ //set how many kilobytes will be sent per time interval define('XMOOV_BW_PACKET_SIZE', 90); //set the time interval in which data packets will be sent in seconds. define('XMOOV_BW_PACKET_INTERVAL', 0.3); //set to TRUE to control bandwidth externally via http. define('XMOOV_CONF_ALLOW_DYNAMIC_BANDWIDTH', TRUE); //------------------------------------------------------------------------------------------ // DYNAMIC BANDWIDTH CONTROL //------------------------------------------------------------------------------------------ function getBandwidthLimit($part) { switch($part) { case 'interval' : switch($_GET[XMOOV_GET_BANDWIDTH]) { case 'low' : return 1; break; case 'mid' : return 0.5; break; case 'high' : return 0.3; break; default : return XMOOV_BW_PACKET_INTERVAL; break; } break; case 'size' : switch($_GET[XMOOV_GET_BANDWIDTH]) { case 'low' : return 10; break; case 'mid' : return 40; break; case 'high' : return 90; break; default : return XMOOV_BW_PACKET_SIZE; break; } break; } } //------------------------------------------------------------------------------------------ // INCOMING GET VARIABLES CONFIGURATION // // use these settings to configure how video files, seek position and bandwidth settings are accessed by your player //------------------------------------------------------------------------------------------ define('XMOOV_GET_FILE', 'file'); define('XMOOV_GET_POSITION', 'position'); define('XMOOV_GET_AUTHENTICATION', 'key'); define('XMOOV_GET_BANDWIDTH', 'bw'); // END SCRIPT CONFIGURATION - do not change anything beyond this point if you do not know what you are doing //------------------------------------------------------------------------------------------ // PROCESS FILE REQUEST //------------------------------------------------------------------------------------------ if(isset($_GET[XMOOV_GET_FILE]) && isset($_GET[XMOOV_GET_POSITION])) { // PROCESS VARIABLES # get seek position $seekPos = intval($_GET[XMOOV_GET_POSITION]); # get file name $fileName = htmlspecialchars($_GET[XMOOV_GET_FILE]); # assemble file path $file = XMOOV_PATH_ROOT . XMOOV_PATH_FILES . $fileName; # assemble packet interval $packet_interval = (XMOOV_CONF_ALLOW_DYNAMIC_BANDWIDTH && isset($_GET[XMOOV_GET_BANDWIDTH])) ? getBandwidthLimit('interval') : XMOOV_BW_PACKET_INTERVAL; # assemble packet size $packet_size = ((XMOOV_CONF_ALLOW_DYNAMIC_BANDWIDTH && isset($_GET[XMOOV_GET_BANDWIDTH])) ? getBandwidthLimit('size') : XMOOV_BW_PACKET_SIZE) * 1042; # security improved by by TRUI www.trui.net if (!file_exists($file)) { print('<b>ERROR:</b> xmoov-php could not find (' . $fileName . ') please check your settings.'); exit(); } if(file_exists($file) && strrchr($fileName, '.') == '.flv' && strlen($fileName) > 2 && !eregi(basename($_SERVER['PHP_SELF']), $fileName) && ereg('^[^./][^/]*$', $fileName)) { # stay clean @ob_end_clean(); @set_time_limit(0); # keep binary data safe set_magic_quotes_runtime(0); $fh = fopen($file, 'rb') or die ('<b>ERROR:</b> xmoov-php could not open (' . $fileName . ')'); $fileSize = filesize($file) - (($seekPos > 0) ? $seekPos + 1 : 0); // SEND HEADERS if(!XMOOV_CONF_ALLOW_FILE_CACHE) { # prohibit caching (different methods for different clients) session_cache_limiter("nocache"); header("Expires: Thu, 19 Nov 1981 08:52:00 GMT"); header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); header("Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0"); header("Pragma: no-cache"); } # content headers header("Content-Type: video/x-flv"); header("Content-Disposition: attachment; filename=\"" . $fileName . "\""); header("Content-Length: " . $fileSize); # FLV file format header if($seekPos != 0) { print('FLV'); print(pack('C', 1)); print(pack('C', 1)); print(pack('N', 9)); print(pack('N', 9)); } # seek to requested file position fseek($fh, $seekPos); # output file while(!feof($fh)) { # use bandwidth limiting - by Terry if(XMOOV_CONF_LIMIT_BANDWIDTH) { # get start time list($usec, $sec) = explode(' ', microtime()); $time_start = ((float)$usec + (float)$sec); # output packet print(fread($fh, $packet_size)); # get end time list($usec, $sec) = explode(' ', microtime()); $time_stop = ((float)$usec + (float)$sec); # wait if output is slower than $packet_interval $time_difference = $time_stop - $time_start; # clean up @flush(); @ob_flush(); if($time_difference < (float)$packet_interval) { usleep((float)$packet_interval * 1000000 - (float)$time_difference * 1000000); } } else { # output file without bandwidth limiting print(fread($fh, filesize($file))); } } } } ?>

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  • What's pcap_pkthdr there for?

    - by httpinterpret
    Code snippet from here: void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data) { .... /* retireve the position of the ip header */ ih = (ip_header *) (pkt_data + 14); //length of ethernet header .... What's const struct pcap_pkthdr *header for, when do we need it, how is it populated (since there is no such info in the packet itself as below)?

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  • Abnormally disconnected TCP sockets and write timeout

    - by James
    Hello I will try to explain the problem in shortest possible words. I am using c++ builder 2010. I am using TIdTCPServer and sending voice packets to a list of connected clients. Everything works ok untill any client is disconnected abnormally, For example power failure etc. I can reproduce similar disconnect by cutting the ethernet connection of a connected client. So now we have a disconnected socket but as you know it is not yet detected at server side so server will continue to try to send data to that client too. But when server try to write data to that disconnected client ...... Write() or WriteLn() HANGS there in trying to write, It is like it is wating for somekind of Write timeout. This hangs the hole packet distribution process as a result creating a lag in data transmission to all other clients. After few seconds "Socket Connection Closed" Exception is raised and data flow continues. Here is the code try { EnterCriticalSection(&SlotListenersCriticalSection); for(int i=0;i<SlotListeners->Count;i++) { try { //Here the process will HANG for several seconds on a disconnected socket ((TIdContext*) SlotListeners->Objects[i])->Connection->IOHandler->WriteLn("Some DATA"); }catch(Exception &e) { SlotListeners->Delete(i); } } }__finally { LeaveCriticalSection(&SlotListenersCriticalSection); } Ok i already have a keep alive mechanism which disconnect the socket after n seconds of inactivity. But as you can imagine, still this mechnism cant sync exactly with this braodcasting loop because this braodcasting loop is running almost all the time. So is there any Write timeouts i can specify may be through iohandler or something ? I have seen many many threads about "Detecting disconnected tcp socket" but my problem is little different, i need to avoid that hangup for few seconds during the write attempt. So is there any solution ? Or should i consider using some different mechanism for such data broadcasting for example the broadcasting loop put the data packet in some kind of FIFO buffer and client threads continuously check for available data and pick and deliver it to themselves ? This way if one thread hangs it will not stop/delay the over all distribution thread. Any ideas please ? Thanks for your time and help. Regards Jams

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  • htaccess rewriterule with order in url

    - by NRoscoe
    I'm trying to put together a rewrite rule for an Apache server. It should take 'order/###' and change it to 'order.php?id=###'. For some reason it's rewriting as 'order.php/###'. If I change it to anything other than 'order' my rule works fine. Anyone know what's going on? My .htaccess file looks like this: RewriteEngine on ## tighten host RewriteCond %{HTTP_HOST} !^mydomain\.com$ [NC] RewriteRule .? http://mydomain.com%{REQUEST_URI} [R=301,L] ## Dynamic Pages RewriteRule ^order/([0-9]+)/?$ order.php?code=$1 [L,NC] ## Static Page Redirects RewriteRule ^prices$ /prices.php [L,NC] RewriteRule ^examples$ /examples.php [L,NC] I have no access to the httpd main server config file on the live server.

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  • JAVA or JAVA SCRIPT OR Idoc SCRIPT alphabetical sort

    - by tito86
    Hi folks, I have a task: All items within categories should be sorted alphabetically except for Examples. Special characters and numbers should be displayed before letters. I'm facing with a problem. Most of standart sort functions and plugins are being used the ASCII table. In this table the following symboles: ~,},{ etc. have the index more than letters,for example: Actual result of sorting is: 1 - #1 A T 2 - A T 3 - {C T I need to get: 1 - #1 A T 2 - {C T 3 - A T Plese give me your piece of advice or sny examples ASAP. Best Regards.

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  • Rewriting Live TCP/IP (Layer 4) (i.e. Socket Layer) Streams

    - by user213060
    I have a simple problem which I'm sure someone here has done before... I want to rewrite Layer 4 TCP/IP streams (Not lower layer individual packets or frames.) Ettercap's etterfilter command lets you perform simple live replacements of Layer 4 TCP/IP streams based on fixed strings or regexes. Example ettercap scripting code: if (ip.proto == TCP && tcp.dst == 80) { if (search(DATA.data, "gzip")) { replace("gzip", " "); msg("whited out gzip\n"); } } if (ip.proto == TCP && tcp.dst == 80) { if (search(DATA.data, "deflate")) { replace("deflate", " "); msg("whited out deflate\n"); } } http://ettercap.sourceforge.net/forum/viewtopic.php?t=2833 I would like to rewrite streams based on my own filter program instead of just simple string replacements. Anyone have an idea of how to do this? Is there anything other than Ettercap that can do live replacement like this, maybe as a plugin to a VPN software or something? I would like to have a configuration similar to ettercap's silent bridged sniffing configuration between two Ethernet interfaces. This way I can silently filter traffic coming from either direction with no NATing problems. Note that my filter is an application that acts as a pipe filter, similar to the design of unix command-line filters: >[eth0] <----------> [my filter] <----------> [eth1]< What I am already aware of, but are not suitable: Tun/Tap - Works at the lower packet layer, I need to work with the higher layer streams. Ettercap - I can't find any way to do replacements other than the restricted capabilities in the example above. Hooking into some VPN software? - I just can't figure out which or exactly how. libnetfilter_queue - Works with lower layer packets, not TCP/IP streams. Again, the rewriting should occur at the transport layer (Layer 4) as it does in this example, instead of a lower layer packet-based approach. Exact code will help immensely! Thanks!

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  • How to implement Self-host WCF data serivces (http://localhost:1234/myDataService.svc/...)

    - by warmcold
    I have a project that needs to implement WCF data services (OData) to retrieve data from a control system (.NET Framework Application). The WCF data service needs to be hosted by the .NET application (No ASP.NET and NO IIS). I have seen many WCF Data Service examples recently; they are all hosted by ASP.NET application. I also see the self-host (console application) examples, but it is for WCF Service (not WCF Data Service). Here is my question: It is possible to have a standalone .NET Applications to host WCF Data Services ((http://localhost:1234/mydataservice.svc/...). If yes, can someone provide an example? Thanks.

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  • I want to establish a TCP/IP connection over a UART connection (Windows XP/7)

    - by michael
    I want to connect two computer via serial but for each to see each other via a TCP/IP connection. Ie, create new ethernet ports on the computers that are in actual fact serial ports. The reason for this is that I am actually testing the medium in which the serial connection is made (wireless), and part of the experiment will be to use TCP/IP. Preferably I would use something that I can configure (max packet size and setting serial delimiters).

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  • How to show a ProgressDialog while changing from a activity to another activity?

    - by AndroidUser99
    i want to show a PD when my activity A starts another activity B. But in that onclick method, my A activity haves to do some work before start B, and B also haves to do some work because it haves to load a lot of data for the UI. I need a PD that is viewed by the user in all the process of the loading data of changin from activity A to B. ¿how can do it? i tryed storing a static ProgressDialog on MyApplication.java, and with these methods: public static void showProgressDialog(Context c) { pd = ProgressDialog.show(c, c.getResources().getString(R.string.app_name), c.getResources().getString(R.string.loading), true, false); } public static void dismissProgressDialog(){ pd.dismiss(); } but it doesn't works, it doesn't shows nothing, i dont know why how to achieve this by a easy way? i know that i can do it with async task, but that is too hard for me, i can't understand the code examples i am finding on this web and google code examples are welcome thanks

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  • Re render template when submit a form

    - by Agusti-N
    Hi, i've this problem: I've a view that render a template and then retrive to the user the rendered template. Yesterday i want to add a form. The problem is when i submit this form to the same url that the view render the template, i have to re render the template with previusly data and then show the errors (if they are) in the form with the new renderd data, so i have to re render all the time the previusly information. I've view a lot of examples, but ALL examples have the form in an externar html(separated) How can avoid this ?

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  • basic operations for modifying a source document with XSLT

    - by SpliFF
    All the tutorials and examples I've found of XSLT processing seem to assume your destination will be a significantly different format/structure to your source and that you know the structure of the source in advance. I'm struggling with finding out how to perform simple "in-place" modifications to a HTML document without knowing anything else about its existing structure. Could somebody show me a clear example that, given an arbitrary unknown HTML source will: 1.) delete the classname 'foo' from all divs 2.) delete a node if its empty (ie <p></p>) 3.) delete a <p> node if its first child is <br> 4.) add newattr="newvalue" to all H1 5.) replace 'heading' in text nodes with 'title' 6.) wrap all <u> tags in <b> tags (ie, <u>foo</u> -> <b><u>foo</u></b>) 7.) output the transformed document without changing anything else The above examples are the primary types of transform I wish to accomplish. Understanding how to do the above will go a long way towards helping me build more complex transforms. To help clarify/test the examples here is a sample source and output, however I must reiterate that I want to work with arbitrary samples without rewriting the XSLT for each source: <!doctype html> <html> <body> <h1>heading</h1> <p></p> <p><br>line</p> <div class="foo bar"><u>baz</u></div> <p>untouched</p> </body> </html> output: <!doctype html> <html> <body> <h1 newattr="newvalue">title</h1> <div class="bar"><b><u>baz</u></b></div> <p>untouched</p> </body> </html>

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  • O(log N) == O(1) - Why not?

    - by phoku
    Whenever I consider algorithms/data structures I tend to replace the log(N) parts by constants. Oh, I know log(N) diverges - but does it matter in real world applications? log(infinity) < 100 for all practical purposes. I am really curious for real world examples where this doesn't hold. To clarify: I understand O(f(N)) I am curious about real world examples where the asymptotic behaviour matters more than the constants of the actual performance. If log(N) can be replaced by a constant it still can be replaced by a constant in O( N log N). This question is for the sake of (a) entertainment and (b) to gather arguments to use if I run (again) into a controversy about the performance of a design.

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  • How would I create a technology standards document for my company?

    - by Rob O
    I'm a Director of Product Engineering for my company. My CEO has asked me to create a technology standards document, explaining things like the technology we use, our policy on adapting to new technology, and design standards like percent of code covered by unit tests. I've never had to do something like this, and I've spent a significant amount of time searching the web for examples, but I haven't found any at all. The closest I've found are documents describing technical specifications for an individual product. However, I'm trying to define this for the entire company. Can someone provide examples of how this document could be formatted/organized, and what the typical content would be? Thanks!

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  • Codeigniter Image Library Cropping an Image with 2 sets of coordinates to make square anywhere?

    - by chris
    Spending time reading through the docs, and searching for examples. I understand cropping an image from top 0, and left 0 is pretty straight forward. However. I would like to pass 2 sets of coordinates, a starting point and an ending point. Four Points, a Square that is defined anywhere. However from the examples I am finding, and from what I gather the rendition is not going to let me do this. codeigniter so I am seeking confirmation on this thought, is it true that I can only provide end points from 0, and it crops a square based on said end points or can I actually specify an x start, an x end, and similar for y? Or is there some other technique I can use within codeigniter that will allow me to pass for coordinates for starting and ending points?

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  • Aggregate functions in ANSI SQL

    - by morpheous
    I want to use multiple aggregate functions in a query. All the examples i have seem on aggregate functions however, are trivial. Typically, they are of the form: SELECT field1,agg_func1, agg_func2 GROUP BY SOME_COLUMNS HAVING agg_func1 OP SOME_SCALAR Where: OP: is a boolean operator (e.g. <, = etc) SOME_SCALAR: is a scalar (i.e. a constant number) What I want to know is if it is possible to write (IN ANSI SQL) queries like: SELECT field1,agg_func1, agg_func2, agg_func3 GROUP BY SOME_COLUMNS HAVING (agg_func1 OP1 agg_func2) OP2 (agg_func2 OP3 agg_func3) Where: OP[N] are boolean operators or ANSI SQL clause operators like 'BETWEEN', 'LIKE', 'IN' etc. Also, assuming this is possible (I have not seen any documentation saying otherwise) are there any efficiency/performance considerations (i.e. penalties) when the HAVING clause consists of a boolean expression combining the output of the aggregate functions - instead of the normal comparison of the output of the aggregate with a constant number (e.g. min('salary') 100 ) - which is often used in the most banal examples involving aggregate functions?

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