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  • Hide a base class method from derived class, but still visible outside of assembly

    - by clintp
    This is a question about tidyness. The project is already working, I'm satisfied with the design but I have a couple of loose ends that I'd like to tie up. My project has a plugin architecture. The main body of the program dispatches work to the plugins that each reside in their own AppDomain. The plugins are described with an interface, which is used by the main program (to get the signature for invoking DispatchTaskToPlugin) and by the plugins themselves as an API contract: namespace AppServer.Plugin.Common { public interface IAppServerPlugin { void Register(); void DispatchTaskToPlugin(Task t); // Other methods omitted } } In the main body of the program Register() is called so that the plugin can register its callback methods with the base class, and then later DispatchTaskToPlugin() is called to get the plugin running. The plugins themselves are in two parts. There's a base class that implements the framework for the plugin (setup, housekeeping, teardown, etc..). This is where DispatchTaskToPlugin is actually defined: namespace AppServer.Plugin { abstract public class BasePlugin : MarshalByRefObject, AppServer.Plugin.Common.IAppServerPlugin { public void DispatchTaskToPlugin(Task t) { // ... // Eventual call to actual plugin code // } // Other methods omitted } } The actual plugins themselves only need to implement a Register() method (to give the base class the delegates to call eventually) and then their business logic. namespace AppServer.Plugin { public class Plugin : BasePlugin { override public void Register() { // Calls a method in the base class to register itself. } // Various callback methods, business logic, etc... } } Now in the base class (BasePlugin) I've implemented all kinds of convenience methods, collected data, etc.. for the plugins to use. Everything's kosher except for that lingering method DispatchTaskToPlugin(). It's not supposed to be callable from the Plugin class implementations -- they have no use for it. It's only needed by the dispatcher in the main body of the program. How can I prevent the derived classes (Plugin) from seeing the method in the base class (BasePlugin/DispatchTaskToPlugin) but still have it visible from outside of the assembly? I can split hairs and have DispatchTaskToPlugin() throw an exception if it's called from the derived classes, but that's closing the barn door a little late. I'd like to keep it out of Intellisense or possibly have the compiler take care of this for me. Suggestions?

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  • Methodology to understanding JQuery plugin & API's developed by third parties

    - by Taoist
    I have a question about third party created JQuery plug ins and API's and the methodology for understanding them. Recently I downloaded the JQuery Masonry/Infinite scroll plug in and I couldn't figure out how to configure it based on the instructions. So I downloaded a fully developed demo, then manually deleted everything that wouldn't break the functionality. The code that was left allowed me to understand the plug in much greater detail than the documentation. I'm now having a similar issue with a plug in called JQuery knob. http://anthonyterrien.com/knob/ If you look at the JQuery Knob readme file it says this is working code: <input type="text" value="75" class="dial"> $(function() { $('.dial') .trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); But as far as I can tell it isn't at all. The read me also says the Plug in uses Canvas. I am wondering if I am suppose to wrap this code in a canvas context or if this functionality is already part of the plug in. I know this kind of "question" might not fit in here but I'm a bit confused on the assumptions around reading these kinds of documentation and thought I would post the query regardless. Curious to see if this is due to my "newbi" programming experience or if this is something seasoned coders also fight with. Thank you. Edit In response to Tyanna's reply. I modified the code and it still doesn't work. I posted it below. I made sure that I checked the Google Console to insure the basics were taken care of, such as not getting a read-error on the library. <!DOCTYPE html> <meta charset="UTF-8"> <title>knob</title> <link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/themes/hot-sneaks/jquery-ui.css" type="text/css" /> <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js" charset="utf-8"></script> <script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.21/jquery-ui.min.js"></script> <script src="js/jquery.knob.js"></script> <div id="button1">test </div> <script> $(function() { $("#button1").click(function () { $('.dial').trigger( 'configure', { "min":10, "max":40, "fgColor":"#FF0000", "skin":"tron", "cursor":true } ); }); }); </script>

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  • Compose synthetic English phrase that would contain 160 bits of recoverable information

    - by Alexander Gladysh
    I have 160 bits of random data. Just for fun, I want to generate pseudo-English phrase to "store" this information in. I want to be able to recover this information from the phrase. Note: This is not a security question, I don't care if someone else will be able to recover the information or even detect that it is there or not. Criteria for better phrases, from most important to the least: Short Unique Natural-looking The current approach, suggested here: Take three lists of 1024 nouns, verbs and adjectives each (picking most popular ones). Generate a phrase by the following pattern, reading 20 bits for each word: Noun verb adjective verb, Noun verb adjective verb, Noun verb adjective verb, Noun verb adjective verb. Now, this seems to be a good approach, but the phrase is a bit too long and a bit too dull. I have found a corpus of words here (Part of Speech Database). After some ad-hoc filtering, I calculated that this corpus contains, approximately 50690 usable adjectives 123585 nouns 15301 verbs This allows me to use up to 16 bits per adjective (actually 16.9, but I can't figure how to use fractional bits) 15 bits per noun 13 bits per verb For noun-verb-adjective-verb pattern this gives 57 bits per "sentence" in phrase. This means that, if I'll use all words I can get from this corpus, I can generate three sentences instead of four (160 / 57 ˜ 2.8). Noun verb adjective verb, Noun verb adjective verb, Noun verb adjective verb. Still a bit too long and dull. Any hints how can I improve it? What I see that I can try: Try to compress my data somehow before encoding. But since the data is completely random, only some phrases would be shorter (and, I guess, not by much). Improve phrase pattern, so it would look better. Use several patterns, using the first word in phrase to somehow indicate for future decoding which pattern was used. (For example, use the last letter or even the length of the word.) Pick pattern according to the first bytes of the data. ...I'm not that good with English to come up with better phrase patterns. Any suggestions? Use more linguistics in the pattern. Different tenses etc. ...I guess, I would need much better word corpus than I have now for that. Any hints where can I get a suitable one?

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  • MSSQL 2005: Update rows in a specified order (like ORDER BY)?

    - by JMTyler
    I want to update rows of a table in a specific order, like one would expect if including an ORDER BY clause, but MS SQL does not support the ORDER BY clause in UPDATE queries. I have checked out this question which supplied a nice solution, but my query is a bit more complicated than the one specified there. UPDATE TableA AS Parent SET Parent.ColA = Parent.ColA + (SELECT TOP 1 Child.ColA FROM TableA AS Child WHERE Child.ParentColB = Parent.ColB ORDER BY Child.Priority) ORDER BY Parent.Depth DESC; So, what I'm hoping that you'll notice is that a single table (TableA) contains a hierarchy of rows, wherein one row can be the parent or child of any other row. The rows need to be updated in order from the deepest child up to the root parent. This is because TableA.ColA must contain an up-to-date concatenation of its own current value with the values of its children (I realize this query only concats with one child, but that is for the sake of simplicity - the purpose of the example in this question does not necessitate any more verbosity), therefore the query must update from the bottom up. The solution suggested in the question I noted above is as follows: UPDATE messages SET status=10 WHERE ID in (SELECT TOP (10) Id FROM Table WHERE status=0 ORDER BY priority DESC ); The reason that I don't think I can use this solution is because I am referencing column values from the parent table inside my subquery (see WHERE Child.ParentColB = Parent.ColB), and I don't think two sibling subqueries would have access to each others' data. So far I have only determined one way to merge that suggested solution with my current problem, and I don't think it works. UPDATE TableA AS Parent SET Parent.ColA = Parent.ColA + (SELECT TOP 1 Child.ColA FROM TableA AS Child WHERE Child.ParentColB = Parent.ColB ORDER BY Child.Priority) WHERE Parent.Id IN (SELECT Id FROM TableA ORDER BY Parent.Depth DESC); The WHERE..IN subquery will not actually return a subset of the rows, it will just return the full list of IDs in the order that I want. However (I don't know for sure - please tell me if I'm wrong) I think that the WHERE..IN clause will not care about the order of IDs within the parentheses - it will just check the ID of the row it currently wants to update to see if it's in that list (which, they all are) in whatever order it is already trying to update... Which would just be a total waste of cycles, because it wouldn't change anything. So, in conclusion, I have looked around and can't seem to figure out a way to update in a specified order (and included the reason I need to update in that order, because I am sure I would otherwise get the ever-so-useful "why?" answers) and I am now hitting up Stack Overflow to see if any of you gurus out there who know more about SQL than I do (which isn't saying much) know of an efficient way to do this. It's particularly important that I only use a single query to complete this action. A long question, but I wanted to cover my bases and give you guys as much info to feed off of as possible. :) Any thoughts?

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  • problem while displayin the texture image on view that works fine on iphone simulator but not on dev

    - by yunas
    hello i am trying to display an image on iphone by converting it into texture and then displaying it on the UIView. here is the code to load an image from an UIImage object - (void)loadImage:(UIImage *)image mipmap:(BOOL)mipmap texture:(uint32_t)texture { int width, height; CGImageRef cgImage; GLubyte *data; CGContextRef cgContext; CGColorSpaceRef colorSpace; GLenum err; if (image == nil) { NSLog(@"Failed to load"); return; } cgImage = [image CGImage]; width = CGImageGetWidth(cgImage); height = CGImageGetHeight(cgImage); colorSpace = CGColorSpaceCreateDeviceRGB(); // Malloc may be used instead of calloc if your cg image has dimensions equal to the dimensions of the cg bitmap context data = (GLubyte *)calloc(width * height * 4, sizeof(GLubyte)); cgContext = CGBitmapContextCreate(data, width, height, 8, width * 4, colorSpace, kCGImageAlphaPremultipliedLast); if (cgContext != NULL) { // Set the blend mode to copy. We don't care about the previous contents. CGContextSetBlendMode(cgContext, kCGBlendModeCopy); CGContextDrawImage(cgContext, CGRectMake(0.0f, 0.0f, width, height), cgImage); glGenTextures(1, &(_textures[texture])); glBindTexture(GL_TEXTURE_2D, _textures[texture]); if (mipmap) glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); else glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data); if (mipmap) glGenerateMipmapOES(GL_TEXTURE_2D); err = glGetError(); if (err != GL_NO_ERROR) NSLog(@"Error uploading texture. glError: 0x%04X", err); CGContextRelease(cgContext); } free(data); CGColorSpaceRelease(colorSpace); } The problem that i currently am facing is this code workd perfectly fine and displays the image on simulator where as on the device as seen on debugger an error is displayed i.e. Error uploading texture. glError: 0x0501 any idea how to tackle this bug.... thnx in advance 4 ur soluitons

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  • iPhone memory management

    - by Prazi
    I am newbie to iPhone programming. I am not using Interface Builder in my programming. I have some doubt about memory management, @property topics in iPhone. Consider the following code @interface LoadFlag : UIViewController { UIImage *flag; UIImageView *preview; } @property (nonatomic, retain) UIImageView *preview; @property (nonatomic, retain) UIImage *flag; @implementation @synthesize preview; @synthesize flag; - (void)viewDidLoad { flag = [UIImage imageNamed:@"myImage.png"]]; NSLog(@"Preview: %d\n",[preview retainCount]); //Count: 0 but shouldn't it be 1 as I am retaining it in @property in interface file preview=[[UIImageView alloc]init]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1 preview.frame=CGRectMake(0.0f, 0.0f, 100.0f, 100.0f); preview.image = flag; [self.view addSubview:preview]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 2 [preview release]; NSLog(@"Count: %d\n",[preview retainCount]); //Count: 1 } When & Why(what is the need) do I have to set @property with retain (in above case for UIImage & UIImageView) ? I saw this statement in many sample programs but didn't understood the need of it. When I declare @property (nonatomic, retain) UIImageView *preview; statement the retain Count is 0. Why doesn't it increase by 1 inspite of retaining it in @property. Also when I declare [self.view addSubview:preview]; then retain Count increments by 1 again. In this case does the "Autorelease pool" releases for us later or we have to take care of releasing it. I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it. Now, after the [preview release]; statement my count is 1. Now I don't need UIImageView anymore in my program so when and where should I release it so that the count becomes 0 and the memory gets deallocated. Again, I am not sure but I think that the Autorelease should handle it as we didn't explicitly retained it so why should we worry of releasing it. What will happen if I release it in -(void) dealloc method In the statement - flag = [UIImage imageNamed:@"myImage.png"]]; I haven't allocated any memory to flag but how can I still use it in my program. In this case if I do not allocate memory then who allocates & deallocates memory to it or is the "flag" just a reference pointing to - [UIImage imageNamed:@"myImage.png"]];. If it is a reference only then do i need to release it. Thanks in advance.

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  • Is there a scheduling algorithm that optimizes for "maker's schedules"?

    - by John Feminella
    You may be familiar with Paul Graham's essay, "Maker's Schedule, Manager's Schedule". The crux of the essay is that for creative and technical professionals, meetings are anathema to productivity, because they tend to lead to "schedule fragmentation", breaking up free time into chunks that are too small to acquire the focus needed to solve difficult problems. In my firm we've seen significant benefits by minimizing the amount of disruption caused, but the brute-force algorithm we use to decide schedules is not sophisticated enough to handle scheduling large groups of people well. (*) What I'm looking for is if there's are any well-known algorithms which minimize this productivity disruption, among a group of N makers and managers. In our model, There are N people. Each person pi is either a maker (Mk) or a manager (Mg). Each person has a schedule si. Everyone's schedule is H hours long. A schedule consists of a series of non-overlapping intervals si = [h1, ..., hj]. An interval is either free or busy. Two adjacent free intervals are equivalent to a single free interval that spans both. A maker's productivity is maximized when the number of free intervals is minimized. A manager's productivity is maximized when the total length of free intervals is maximized. Notice that if there are no meetings, both the makers and the managers experience optimum productivity. If meetings must be scheduled, then makers prefer that meetings happen back-to-back, while managers don't care where the meeting goes. Note that because all disruptions are treated as equally harmful to makers, there's no difference between a meeting that lasts 1 second and a meeting that lasts 3 hours if it segments the available free time. The problem is to decide how to schedule M different meetings involving arbitrary numbers of the N people, where each person in a given meeting must place a busy interval into their schedule such that it doesn't overlap with any other busy interval. For each meeting Mt the start time for the busy interval must be the same for all parties. Does an algorithm exist to solve this problem or one similar to it? My first thought was that this looks really similar to defragmentation (minimize number of distinct chunks), and there are a lot of algorithms about that. But defragmentation doesn't have much to do with scheduling. Thoughts? (*) Practically speaking this is not really a problem, because it's rare that we have meetings with more than ~5 people at once, so the space of possibilities is small.

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  • R: Plotting a graph with different colors of points based on advanced criteria

    - by balconydoor
    What I would like to do is a plot (using ggplot), where the x axis represent years which have a different colour for the last three years in the plot than the rest. The last three years should also meet a certain criteria and based on this the last three years can either be red or green. The criteria is that the mean of the last three years should be less (making it green) or more (making it red) than the 66%-percentile of the remaining years. So far I have made two different functions calculating the last three year mean: LYM3 <- function (x) { LYM3 <- tail(x,3) mean(LYM3$Data,na.rm=T) } And the 66%-percentile for the remaining: perc66 <- function(x) { percentile <- head(x,-3) quantile(percentile$Data, .66, names=F,na.rm=T) } Here are two sets of data that can be used in the calculations (plots), the first which is an example from my real data where LYM3(df1) < perc66(df1) and the second is just made up data where LYM3 perc66. df1<- data.frame(Year=c(1979:2010), Data=c(347261.87, 145071.29, 110181.93, 183016.71, 210995.67, 205207.33, 103291.78, 247182.10, 152894.45, 170771.50, 206534.55, 287770.86, 223832.43, 297542.86, 267343.54, 475485.47, 224575.08, 147607.81, 171732.38, 126818.10, 165801.08, 136921.58, 136947.63, 83428.05, 144295.87, 68566.23, 59943.05, 49909.08, 52149.11, 117627.75, 132127.79, 130463.80)) df2 <- data.frame(Year=c(1979:2010), Data=c(sample(50,29,replace=T),75,75,75)) Here’s my code for my plot so far: plot <- ggplot(df1, aes(x=Year, y=Data)) + theme_bw() + geom_point(size=3, aes(colour=ifelse(df1$Year<2008, "black",ifelse(LYM3(df1) < perc66(df1),"green","red")))) + geom_line() + scale_x_continuous(breaks=c(1980,1985,1990,1995,2000,2005,2010), limits=c(1978,2011)) plot As you notice it doesn’t really do what I want it to do. The only thing it does seem to do is that it turns the years before 2008 into one level and those after into another one and base the point colour off these two levels. Since I don’t want this year to be stationary either, I made another tiny function: fun3 <- function(x) { df <- subset(x, Year==(max(Year)-2)) df$Year } So the previous code would have the same effect as: geom_point(size=3, aes(colour=ifelse(df1$Year<fun3(df1), "black","red"))) But it still does not care about my colours. Why does it make the years into levels? And how come an ifelse function doesn’t work within another one in this case? How would it be possible to the arguments to do what I like? I realise this might be a bit messy, asking for a lot at the same time, but I hope my description is pretty clear. It would be helpful if someone could at least point me in the right direction. I tried to put the code for the plot into a function as well so I wouldn’t have to change the data frame at all functions within the plot, but I can’t get it to work. Thank you!

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  • Hibernate3: Self-Referencing Objects

    - by monojohnny
    Need some help on understanding how to do this; I'm going to be running recursive 'find' on a file system and I want to keep the information in a single DB table - with a self-referencing hierarchial structure: This is my DB Table structure I want to populate. DirObject Table: id int NOT NULL, name varchar(255) NOT NULL, parentid int NOT NULL); Here is the proposed Java Class I want to map (Fields only shown): public DirObject { int id; String name; DirObject parent; ... For the 'root' directory was going to use parentid=0; real ids will start at 1, and ideally I want hibernate to autogenerate the ids. Can somebody provide a suggested mapping file for this please; as a secondary question I thought about doing the Java Class like this instead: public DirObject { int id; String name; List<DirObject> subdirs; Could I use the same data model for either of these two methods ? (With a different mapping file of course). --- UPDATE: so I tried the mapping file suggested below (thanks!), repeated here for reference: <hibernate-mapping> <class name="my.proj.DirObject" table="category"> ... <set name="subDirs" lazy="true" inverse="true"> <key column="parentId"/> <one-to-many class="my.proj.DirObject"/> </set> <many-to-one name="parent" class="my.proj.DirObject" column="parentId" cascade="all" /> </class> ...and altered my Java class to have BOTH 'parentid' and 'getSubDirs' [returning a 'HashSet']. This appears to work - thanks, but this is the test code I used to drive this - I think I'm not doing something right here, because I thought Hibernate would take care of saving the subordinate objects in the Set without me having to do this explicitly ? DirObject dirobject=new DirObject(); dirobject.setName("/files"); dirobject.setParent(dirobject); DirObject d1, d2; d1=new DirObject(); d1.setName("subdir1"); d1.setParent(dirobject); d2=new DirObject(); d2.setName("subdir2"); d2.setParent(dirobject); HashSet<DirObject> subdirs=new HashSet<DirObject>(); subdirs.add(d1); subdirs.add(d2); dirobject.setSubdirs(subdirs); session.save(dirobject); session.save(d1); session.save(d2);

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  • Publish to Facebook Stream via PHP using Graph API

    - by Liquid
    I'm trying to post a message to a user's wall using the new graph API and PHP. Connection seems to work fine, but no post appears. I'm not sure how to set up the posting code correctly. Please help me out. Sorry for the broken-looking code, for some reason StackOverflow didn't want to close it all in the code block. Below is my full code. Am I missing an extender permission requests, or is that taken care in this code: PHP Code <?php include_once 'facebook.php'; $facebook = new Facebook(array( 'appId' => 'xxxxxxxxxxxxxxxxxx', 'secret' => 'xxxxxxxxxxxxxxxxxxxxxxxxxx', 'cookie' => true )); $session = $facebook->getSession(); if (!$session) { $url = $facebook->getLoginUrl(array( 'canvas' => 1, 'fbconnect' => 0 )); echo "<script type='text/javascript'>top.location.href = '$url';</script>"; } else { try { $uid = $facebook->getUser(); $me = $facebook->api('/me'); $updated = date("l, F j, Y", strtotime($me['updated_time'])); echo "Hello " . $me['name'] . "<br />"; echo "You last updated your profile on " . $updated; $connectUrl = $facebook->getUrl( 'www', 'login.php', array_merge(array( 'api_key' => $facebook->getAppId(), 'cancel_url' => 'http://www.test.com', 'req_perms' => 'publish_stream', 'display' => 'page', 'fbconnect' => 1, 'next' => 'http://www.test.com', 'return_session' => 1, 'session_version' => 3, 'v' => '1.0', ), $params) ); $result = $facebook->api( '/me/feed/', 'post', array('access_token' => $facebook->access_token, 'message' => 'Playing around with FB Graph..') ); } catch (FacebookApiException $e) { echo "Error:" . print_r($e, true); } } ?>

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  • How can I create the XML::Simple data structure using a Perl XML SAX parser?

    - by DVK
    Summary: I am looking a fast XML parser (most likely a wrapper around some standard SAX parser) which will produce per-record data structure 100% identical to those produced by XML::Simple. Details: We have a large code infrastructure which depends on processing records one-by-one and expects the record to be a data structure in a format produced by XML::Simple since it always used XML::Simple since early Jurassic era. An example simple XML is: <root> <rec><f1>v1</f1><f2>v2</f2></rec> <rec><f1>v1b</f1><f2>v2b</f2></rec> <rec><f1>v1c</f1><f2>v2c</f2></rec> </root> And example rough code is: sub process_record { my ($obj, $record_hash) = @_; # do_stuff } my $records = XML::Simple->XMLin(@args)->{root}; foreach my $record (@$records) { $obj->process_record($record) }; As everyone knows XML::Simple is, well, simple. And more importantly, it is very slow and a memory hog—due to being a DOM parser and needing to build/store 100% of data in memory. So, it's not the best tool for parsing an XML file consisting of large amount of small records record-by-record. However, re-writing the entire code (which consist of large amount of "process_record"-like methods) to work with standard SAX parser seems like an big task not worth the resources, even at the cost of living with XML::Simple. I'm looking for an existing module which will probably be based on a SAX parser (or anything fast with small memory footprint) which can be used to produce $record hashrefs one by one based on the XML pictured above that can be passed to $obj->process_record($record) and be 100% identical to what XML::Simple's hashrefs would have been. I don't care much what the interface of the new module is; e.g whether I need to call next_record() or give it a callback coderef accepting a record.

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  • Summarising (permanently) data in a SQL table

    - by Cylindric
    Geetings, Stackers. I have a huge number of data-points in a SQL table, and I want to summarise them in a way reminiscent of RRD. Assuming a table such as ID | ENTITY_ID | SCORE_DATE | SCORE | SOME_OTHER_DATA ----+-----------+------------+-------+----------------- 1 | A00000001 | 01/01/2010 | 100 | some data 2 | A00000002 | 01/01/2010 | 105 | more data 3 | A00000003 | 01/01/2010 | 104 | various text ... | ......... | .......... | ..... | ... ... | A00009999 | 01/01/2010 | 101 | ... | A00000001 | 02/01/2010 | 104 | ... | A00000002 | 02/01/2010 | 119 | ... | A00000003 | 02/01/2010 | 119 | ... | ......... | .......... | ..... | ... | A00009999 | 02/01/2010 | 101 | arbitrary data ... | ......... | .......... | ..... | ... ... | A00000001 | 01/02/2010 | 104 | ... | A00000002 | 01/02/2010 | 119 | ... | A00000003 | 01/01/2010 | 119 | I want to end up with one record per entity, per month: ID | ENTITY_ID | SCORE_DATE | SCORE | ----+-----------+------------+-------+ ... | A00000001 | 01/01/2010 | 100 | ... | A00000002 | 01/01/2010 | 105 | ... | A00000003 | 01/01/2010 | 104 | ... | A00000001 | 01/02/2010 | 100 | ... | A00000002 | 01/02/2010 | 105 | ... | A00000003 | 01/02/2010 | 104 | (I Don't care about the SOME_OTHER_DATA - I'll pick something - either the first or last record probably.) What's an easy way of doing this on a regular basis, so that anything in the last calendar month is summarised in this way? At the moment my plan is kind of: For each EntityID For each month Find average score for all records in given month Update first record with results of previous step Delete all records that aren't the first I can't think of a neat way of doing it though, that doesn't involve lots of updates and iteration. This can either be done in a SQL Stored Procedure, or it can be incorporated into the .Net app that's generating this data, so the solution doesn't really need to be "one big SQL script", but can be :) (SQL-2005)

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  • Windows Question: RunOnce/Second Boot Issues [closed]

    - by Greg
    Moved to Super User: Windows Question: RunOnce/Second Boot Issues I am attempting to create a Windows XP SP3 image that will run my application on Second Boot. Here is the intended workflow. 1) Run Image Prep Utility (I wrote) on windows to add my runonce entries and clean a few things up. 2) Reboot to ghost, make image file. 3) Package into my ISO and distribute. 4) System will be imaged by user. 5) On first boot, I have about 5 things that run, one of which includes a driver updater (I wrote) for my own specific devices. 6) One of the entries inside of HKCU/../runonce is a reg file, which adds another key to HKLM/../runonce. This is how second boot is acquired. 7) As a result of the driver updater, user is prompted to reboot. 8) My application is then launched from HKLM/../runonce on second boot. This workflow works perfectly, except for a select few legacy systems that contain devices that cause the add hardware wizard to pop up. When the add hardware wizard pops up is when I begin to see problems. It's important to note, that if I manually inspect the registry after the add hardware wizard pops up, it appears as I would expect, with all the first boot scripts having run, and it's sitting in a state I would correctly expect it to be in for a second boot scenario. The problem comes when I click next on the add hardware wizard, it seems to re-run the single entry I've added, and re-executes the runonce scripts. (only one script now as it's already executed and cleared out the initial entries). This causes my application to open as if it were a second boot, only when next is clicked on the add hardware wizard. If I click cancel, and reboot, then it also works as expected. I don't care as much about other solutions, because I could design a system that doesn't fully rely on Microsoft's registry. I simply can't find any information as to WHY this is happening. I believe this is some type of Microsoft issue that's presenting itself as a result of an overstretched image that's expected to support too many legacy platforms, but any help that can be provided would be appreciated. Thanks,

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  • Do You Really Know Your Programming Languages?

    - by Kristopher Johnson
    I am often amazed at how little some of my colleagues know or care about their craft. Something that constantly frustrates me is that people don't want to learn any more than they need to about the programming languages they use every day. Many programmers seem content to learn some pidgin sub-dialect, and stick with that. If they see a keyword or construct that they aren't familiar with, they'll complain that the code is "tricky." What would you think of a civil engineer who shied away from calculus because it had "all those tricky math symbols?" I'm not suggesting that we all need to become "language lawyers." But if you make your living as a programmer, and claim to be a competent user of language X, then I think at a minimum you should know the following: Do you know the keywords of the language and what they do? What are the valid syntactic forms? How are memory, files, and other operating system resources managed? Where is the official language specification and library reference for the language? The last one is the one that really gets me. Many programmers seem to have no idea that there is a "specification" or "standard" for any particular language. I still talk to people who think that Microsoft invented C++, and that if a program doesn't compile under VC6, it's not a valid C++ program. Programmers these days have it easy when it comes to obtaining specs. Newer languages like C#, Java, Python, Ruby, etc. all have their documentation available for free from the vendors' web sites. Older languages and platforms often have standards controlled by standards bodies that demand payment for specs, but even that shouldn't be a deterrent: the C++ standard is available from ISO for $30 (and why am I the only person I know who has a copy?). Programming is hard enough even when you do know the language. If you don't, I don't see how you have a chance. What do the rest of you think? Am I right, or should we all be content with the typical level of programming language expertise? Update: Several great comments here. Thanks. A couple of people hit on something that I didn't think about: What really irks me is not the lack of knowledge, but the lack of curiosity and willingness to learn. It seems some people don't have any time to hone their craft, but they have plenty of time to write lots of bad code. And I don't expect people to be able to recite a list of keywords or EBNF expressions, but I do expect that when they see some code, they should have some inkling of what it does. Few people have complete knowledge of every dark corner of their language or platform, but everyone should at least know enough that when they see something unfamiliar, they will know how to get whatever additional information they need to understand it.

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  • Marshalling non-Blittable Structs from C# to C++

    - by Greggo
    I'm in the process of rewriting an overengineered and unmaintainable chunk of my company's library code that interfaces between C# and C++. I've started looking into P/Invoke, but it seems like there's not much in the way of accessible help. We're passing a struct that contains various parameters and settings down to unmanaged codes, so we're defining identical structs. We don't need to change any of those parameters on the C++ side, but we do need to access them after the P/Invoked function has returned. My questions are: What is the best way to pass strings? Some are short (device id's which can be set by us), and some are file paths (which may contain Asian characters) Should I pass an IntPtr to the C# struct or should I just let the Marshaller take care of it by putting the struct type in the function signature? Should I be worried about any non-pointer datatypes like bools or enums (in other, related structs)? We have the treat warnings as errors flag set in C++ so we can't use the Microsoft extension for enums to force a datatype. Is P/Invoke actually the way to go? There was some Microsoft documentation about Implicit P/Invoke that said it was more type-safe and performant. For reference, here is one of the pairs of structs I've written so far: C++ /** Struct used for marshalling Scan parameters from managed to unmanaged code. */ struct ScanParameters { LPSTR deviceID; LPSTR spdClock; LPSTR spdStartTrigger; double spinRpm; double startRadius; double endRadius; double trackSpacing; UINT64 numTracks; UINT32 nominalSampleCount; double gainLimit; double sampleRate; double scanHeight; LPWSTR qmoPath; //includes filename LPWSTR qzpPath; //includes filename }; C# /// <summary> /// Struct used for marshalling scan parameters between managed and unmanaged code. /// </summary> [StructLayout(LayoutKind.Sequential)] public struct ScanParameters { [MarshalAs(UnmanagedType.LPStr)] public string deviceID; [MarshalAs(UnmanagedType.LPStr)] public string spdClock; [MarshalAs(UnmanagedType.LPStr)] public string spdStartTrigger; public Double spinRpm; public Double startRadius; public Double endRadius; public Double trackSpacing; public UInt64 numTracks; public UInt32 nominalSampleCount; public Double gainLimit; public Double sampleRate; public Double scanHeight; [MarshalAs(UnmanagedType.LPWStr)] public string qmoPath; [MarshalAs(UnmanagedType.LPWStr)] public string qzpPath; }

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  • How to Load Dependent Files on Demand + Check if They're Loaded or Not?

    - by br4inwash3r
    I'm trying to implement an assets/dependency loader that i've found from an old article at 24Ways.org. most of you might be familiar with it. it's from this article by Christian Heilmann: http://24ways.org/2007/keeping-javascript-dependencies-at-bay i've modified the script to load CSS files as well. and it's now quite close to what i want. but i still need to do some checking to see wether an asset have been completely loaded or not. just wondering if you guys have any ideas :) here's what my script currently looked like: var assetLoader = { assets: { products: { js: 'products.js', css: 'products.css', loaded: false }, articles: { js: 'articles.js', css: 'articles.css', loaded: false }, [...] cycle: { js: 'jquery.cycle.min.js', loaded: false }, swfobject: { js: 'jquery.swfobject.min.js', loaded: false } }, add: function(asset) { var comp = assetLoader.assets[asset]; var path = '/path/to/assets/'; if (comp && comp.loaded == false) { if (comp.js) { // load js var js = document.createElement('script'); js.src = path + 'js/' + comp.js; js.type = 'text/javascript'; js.charset = 'utf-8'; // append to document document.getElementsByTagName('body')[0].appendChild(js); } if (comp.css) { // load css var css = document.createElement('link'); css.rel = 'stylesheet'; css.href = path + 'css/' + comp.css; css.type = 'text/css'; css.media = 'screen, projection'; css.charset = 'utf-8'; // append to document document.getElementsByTagName('head')[0].appendChild(css); } } }, check: function(asset) { assetLoader.assets[asset].loaded = true; } } Christian explains this method in his article in great detail. I don't want to confuse you guys anymore with my bad english :P and here's an example of how i run the script: ... // load jquery cycle plugin if (page=='tvc' || page=='products') { if (!assetLoader.assets.cycle.loaded) { assetLoader.add('cycle'); } } // load products page assets if (!assetLoader.assets.products.loaded) { assetLoader.add('products'); } ... this kind of approach is very problematic though. coz assets loads asynchronously, which means some of the code inside products.js that depends on jquery.cycle.js might continue running before jquery.cycle.js is even loaded resulting in errors. while i'm quite aware that scripts can be attached with an onload event, i'm just not really sure how to implement it to my script. anyone care to help me? please... :P

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  • How to return a property name when comparing two properties at class-level

    - by CodeMonkey
    Hi I have implemented an 'EqualTo' Validation Attribute, that compares two Properties of an object, during ModelBinding in ASP.NET MVC 2. The problem I have is not with it not working, because it does work. The problem is, when I do my request - which is an ajax request - I get back errors to my front-end, where it sets a class on the input fields to indicate invalid input. What it does is iterate through a list of Errors (in a JsonResult), and set a class. This is all dandy. But the ValidationAtrribute I am having trouble with is set at a Class-level, i.e., it's not like other ValidationAttributes where you set something like "[Required]" or something like that. [AttributeUsage(AttributeTargets.Class, AllowMultiple=true, Inherited=false)] public class EqualToAttribute : ValidationAttribute { public String SourceProperty { get; set; } public String MatchProperty { get; set; } public EqualToAttribute(string source, string match) { SourceProperty = source; MatchProperty = match; } public override Boolean IsValid(Object value) { Type objectType = value.GetType(); PropertyInfo[] properties = objectType.GetProperties(); object sourceValue = new object(); object matchValue = new object(); Type sourceType = null; Type matchType = null; int counter = 0; foreach (PropertyInfo propertyInfo in properties) { if (propertyInfo.Name == SourceProperty || propertyInfo.Name == MatchProperty) { if (counter == 0) { sourceValue = propertyInfo.GetValue(value, null); sourceType = propertyInfo.GetValue(value, null).GetType(); } if (counter == 1) { matchValue = propertyInfo.GetValue(value, null); matchType = propertyInfo.GetValue(value, null).GetType(); } counter++; if (counter == 2) { break; } } } if (sourceType != null && matchType != null) { return sourceValue.ToString().Equals(matchValue.ToString()); //return Convert.ChangeType(sourceValue, sourceType) == Convert.ChangeType(matchValue, matchType); } return false; } private object _typeId = new object(); public override object TypeId { get { return this._typeId; } } } Now this code works, except for the fact that the validation process does not return which Property failed. And I simply can't figure out how to make it return one of the two. In reality I don't care which one it returns.. because both are failing.. Do you have an idea how to make it return the/or both Property/Properties that is/are failing.

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  • Releasing the keyboard stops shake events. Why?

    - by Moshe
    1) How do I make a UITextField resign the keyboard and hide it? The keyboard is in a dynamically created subview whose superview looks for shake events. Resigning first responder seems to break the shake event handler. 2) how do you make the view holding the keyboard transparent, like see through glass? I have seen this done before. This part has been taken care of thanks guys. As always, code samples are appreciated. I've added my own to help explain the problem. EDIT: Basically, - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event; gets called in my main view controller to handle shaking. When a user taps on the "edit" icon (a pen, in the bottom of the screen - not the traditional UINavigationBar edit button), the main view adds a subview to itself and animates it on to the screen using a custom animation. This subview contains a UINavigationController which holds a UITableView. The UITableView, when a cell is tapped on, loads a subview into itself. This second subview is the culprit. For some reason, a UITextField in this second subview is causing problems. When a user taps on the view, the main view will not respond to shakes unless the UITextField is active (in editing mode?). Additional info: My Motion Event Handler: - (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event { NSLog(@"%@", [event description]); SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"shake" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); [self genRandom:TRUE]; } The genRandom: Method: /* Generate random label and apply it */ -(void)genRandom:(BOOL)deviceWasShaken{ if(deviceWasShaken == TRUE){ decisionText.text = [NSString stringWithFormat: (@"%@", [shakeReplies objectAtIndex:(arc4random() % [shakeReplies count])])]; }else{ SystemSoundID SoundID; NSString *soundFile = [[NSBundle mainBundle] pathForResource:@"string" ofType:@"aif"]; AudioServicesCreateSystemSoundID((CFURLRef)[NSURL fileURLWithPath:soundFile], &SoundID); AudioServicesPlayAlertSound(SoundID); decisionText.text = [NSString stringWithFormat: (@"%@", [pokeReplies objectAtIndex:(arc4random() % [pokeReplies count])])]; } } shakeReplies and pokeReplies are both NSArrays of strings. One is used for when a certain part of the screen is poked and one is for when the device is shaken. The app will randomly choose a string from the NSArray and display onscreen. For those of you who work graphically, here is a diagram of the view hierarchy: Root View -> UINavigationController -> UITableView -> Edit View -> Problem UITextfield

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  • Exporting classes containing std:: objects (vector, map, etc) from a dll

    - by RnR
    I'm trying to export classes from a DLL that contain objects such as std::vectors and std::stings - the whole class is declared as dll export through: class DLL_EXPORT FontManager { The problem is that for members of the complex types I get this warning: warning C4251: 'FontManager::m__fonts' : class 'std::map<_Kty,_Ty' needs to have dll-interface to be used by clients of class 'FontManager' with [ _Kty=std::string, _Ty=tFontInfoRef ] I'm able to remove some of the warnings by putting the following forward class declaration before them even though I'm not changing the type of the member variables themselves: template class DLL_EXPORT std::allocator<tCharGlyphProviderRef>; template class DLL_EXPORT std::vector<tCharGlyphProviderRef,std::allocator<tCharGlyphProviderRef> >; std::vector<tCharGlyphProviderRef> m_glyphProviders; Looks like the forward declaration "injects" the DLL_EXPORT for when the member is compiled but is it safe? Does it realy change anything when the client compiles this header and uses the std container on his side? Will it make all future uses of such a container DLL_EXPORT (and possibly not inline?)? And does it really solve the problem that the warning tries to warn about? Is this warning anything I should be worried about or would it be best to disable it in the scope of these constructs? The clients and the dll will always be built using the same set of libraries and compilers and those are header only classes... I'm using Visual Studio 2003 with the standard STD library. ---- Update ---- I'd like to target you more though as I see the answers are general and here we're talking about std containers and types (such as std::string) - maybe the question really is: Can we disable the warning for standard containers and types available to both the client and the dll through the same library headers and treat them just as we'd treat an int or any other built-in type? (It does seem to work correctly on my side.) If so would should be the conditions under which we can do this? Or should maybe using such containers be prohibited or at least ultra care taken to make sure no assignment operators, copy constructors etc will get inlined into the dll client? In general I'd like to know if you feel designing a dll interface having such objects (and for example using them to return stuff to the client as return value types) is a good idea or not and why - I'd like to have a "high level" interface to this functionality... maybe the best solution is what Neil Butterworth suggested - creating a static library?

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  • SQL Native Client 10 Performance miserable (due to server-side cursors)

    - by namezero
    we have an application that uses ODBC via CDatabase/CRecordset in MFC (VS2010). We have two backends implemented. MSSQL and MySQL. Now, when we use MSSQL (with the Native Client 10.0), retrieving records with SELECT is dramatically slow via slow links (VPN, for example). The MySQL ODBC driver does not exhibit this nasty behavior. For example: CRecordset r(&m_db); r.Open(CRecordset::snapshot, L"SELECT a.something, b.sthelse FROM TableA AS a LEFT JOIN TableB AS b ON a.ID=b.Ref"); r.MoveFirst(); while(!r.IsEOF()) { // Retrieve CString strData; crs.GetFieldValue(L"a.something", strData); crs.MoveNext(); } Now, with the MySQL driver, everything runs as it should. The query is returned, and everything is lightning fast. However, with the MSSQL Native Client, things slow down, because on every MoveNext(), the driver communicates with the server. I think it is due to server-side cursors, but I didn't find a way to disable them. I have tried using: ::SQLSetConnectAttr(m_db.m_hdbc, SQL_ATTR_ODBC_CURSORS, SQL_CUR_USE_ODBC, SQL_IS_INTEGER); But this didn't help either. There are still long-running exec's to sp_cursorfetch() et al in SQL Profiler. I have also tried a small reference project with SQLAPI and bulk fetch, but that hangs in FetchNext() for a long time, too (even if there is only one record in the resultset). This however only happens on queries with LEFT JOINS, table-valued functions, etc. Note that the query doesn't take that long - executing the same SQL via SQL Studio over the same connection returns in a reasonable time. Question1: Is is possible to somehow get the native client to "cache" all results locally use local cursors in a similar fashion as the MySQL driver seems to do it? Maybe this is the wrong approach altogether, but I'm not sure how else to do this. All we want is to retrieve all data at once from a SELECT, then never talk the server again until the next query. We don't care about recordset updates, deletes, etc or any of that nonsense. We only want to retrieve data. We take that recordset, get all the data, and delete it. Question2: Is there a more efficient way to just retrieve data in MFC with ODBC?

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  • How to implement a caching model without violating MVC pattern?

    - by RPM1984
    Hi Guys, I have an ASP.NET MVC 3 (Razor) Web Application, with a particular page which is highly database intensive, and user experience is of the upmost priority. Thus, i am introducing caching on this particular page. I'm trying to figure out a way to implement this caching pattern whilst keeping my controller thin, like it currently is without caching: public PartialViewResult GetLocationStuff(SearchPreferences searchPreferences) { var results = _locationService.FindStuffByCriteria(searchPreferences); return PartialView("SearchResults", results); } As you can see, the controller is very thin, as it should be. It doesn't care about how/where it is getting it's info from - that is the job of the service. A couple of notes on the flow of control: Controllers get DI'ed a particular Service, depending on it's area. In this example, this controller get's a LocationService Services call through to an IQueryable<T> Repository and materialize results into T or ICollection<T>. How i want to implement caching: I can't use Output Caching - for a few reasons. First of all, this action method is invoked from the client-side (jQuery/AJAX), via [HttpPost], which according to HTTP standards should not be cached as a request. Secondly, i don't want to cache purely based on the HTTP request arguments - the cache logic is a lot more complicated than that - there is actually two-level caching going on. As i hint to above, i need to use regular data-caching, e.g Cache["somekey"] = someObj;. I don't want to implement a generic caching mechanism where all calls via the service go through the cache first - i only want caching on this particular action method. First thought's would tell me to create another service (which inherits LocationService), and provide the caching workflow there (check cache first, if not there call db, add to cache, return result). That has two problems: The services are basic Class Libraries - no references to anything extra. I would need to add a reference to System.Web here. I would have to access the HTTP Context outside of the web application, which is considered bad practice, not only for testability, but in general - right? I also thought about using the Models folder in the Web Application (which i currently use only for ViewModels), but having a cache service in a models folder just doesn't sound right. So - any ideas? Is there a MVC-specific thing (like Action Filter's, for example) i can use here? General advice/tips would be greatly appreciated.

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  • How do I make a full screen scrolling messagebox or window?

    - by chobo2
    Hi First let me start of saying I know absolutely nothing about c++ and I am really just more interested in getting this to work then learning c++(I got enough on my plate to learn). So basically I am trying to make a terms of service for my windows mobile 6 professional application but it seems I need to use c++ to do it. After hours of searching I found a solution but it developed for windows mobile standard. So they somehow used c++ to make a message box and on standard devices(ie non touch screen phones) the message box can have like scrolling. For some reason this is not the case with professional devices(touch screen devices). So my message box goes off the page and you can never accept or decline the terms. So your stuck and on the screen forever till you do some sort of soft restart. http://www.mobilepractices.com/2008/10/setupdll-sample-and-walkthrough-terms.html The above link is the tutorial but here is the actual file that seems to display the message. #include "stdafx.h" #include "ce_setup.h" // This is a variable containing the text to be displayed // in the Terms & Conditions dialog TCHAR Message[] = _T("TERMS & CONDITIONS\r\n ") _T("Selecting YES you're accepting our terms & conditions.\r\n") _T("This is just a sample application.\r\n") _T("From http://www.mobilepractices.com\r\n") _T("You can replace this text with your own.\r\n") _T("We're using a setup.dll to show this dialog.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Extra line to force vertical scrollbar.\r\n") _T("Last line.\r\n") ; // This function will be called when the user // tries to install the cab. According to its return // value the installation continues or is cancelled. // As this could be called more than once // (i.e. if there is not enough space on the target) // we should take care about fFirstCall parameter // to show the dialog only once. codeINSTALL_INIT Install_Init( HWND hwndParent, BOOL fFirstCall, BOOL fPreviouslyInstalled, LPCTSTR pszInstallDir ) { if (!fFirstCall || ::MessageBoxW(0, Message, _T("SplashScreenSample") , MB_YESNO) == IDYES) return codeINSTALL_INIT_CONTINUE; else return codeINSTALL_INIT_CANCEL; } So I want to change this to something that can scroll. Can I use like a panel control since I know what has scroll or something else? Thanks

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  • How to compute a unicode string which bidirectional representation is specified?

    - by valdo
    Hello, fellows. I have a rather pervert question. Please forgive me :) There's an official algorithm that describes how bidirectional unicode text should be presented. http://www.unicode.org/reports/tr9/tr9-15.html I receive a string (from some 3rd-party source), which contains latin/hebrew characters, as well as digits, white-spaces, punctuation symbols and etc. The problem is that the string that I receive is already in the representation form. I.e. - the sequence of characters that I receive should just be presented from left to right. Now, my goal is to find the unicode string which representation is exactly the same. Means - I need to pass that string to another entity; it would then render this string according to the official algorithm, and the result should be the same. Assuming the following: The default text direction (of the rendering entity) is RTL. I don't want to inject "special unicode characters" that explicitly override the text direction (such as RLO, RLE, etc.) I suspect there may exist several solutions. If so - I'd like to preserve the RTL-looking of the string as much as possible. The string usually consists of hebrew words mostly. I'd like to preserve the correct order of those words, and characters inside those words. Whereas other character sequences may (and should) be transposed. One naive way to solve this is just to swap the whole string (this takes care of the hebrew words), and then swap inside it sequences of non-hebrew characters. This however doesn't always produce correct results, because actual rules of representation are rather complex. The only comprehensive algorithm that I see so far is brute-force check. The string can be divided into sequences of same-class characters. Those sequences may be joined in random order, plus any of them may be reversed. I can check all those combinations to obtain the correct result. Plus this technique may be optimized. For instance the order of hebrew words is known, so we only have to check different combinations of their "joining" sequences. Any better ideas? If you have an idea, not necessarily the whole solution - it's ok. I'll appreciate any idea. Thanks in advance.

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  • Combining FileStream and MemoryStream to avoid disk accesses/paging while receiving gigabytes of data?

    - by w128
    I'm receiving a file as a stream of byte[] data packets (total size isn't known in advance) that I need to store somewhere before processing it immediately after it's been received (I can't do the processing on the fly). Total received file size can vary from as small as 10 KB to over 4 GB. One option for storing the received data is to use a MemoryStream, i.e. a sequence of MemoryStream.Write(bufferReceived, 0, count) calls to store the received packets. This is very simple, but obviously will result in out of memory exception for large files. An alternative option is to use a FileStream, i.e. FileStream.Write(bufferReceived, 0, count). This way, no out of memory exceptions will occur, but what I'm unsure about is bad performance due to disk writes (which I don't want to occur as long as plenty of memory is still available) - I'd like to avoid disk access as much as possible, but I don't know of a way to control this. I did some testing and most of the time, there seems to be little performance difference between say 10 000 consecutive calls of MemoryStream.Write() vs FileStream.Write(), but a lot seems to depend on buffer size and the total amount of data in question (i.e the number of writes). Obviously, MemoryStream size reallocation is also a factor. Does it make sense to use a combination of MemoryStream and FileStream, i.e. write to memory stream by default, but once the total amount of data received is over e.g. 500 MB, write it to FileStream; then, read in chunks from both streams for processing the received data (first process 500 MB from the MemoryStream, dispose it, then read from FileStream)? Another solution is to use a custom memory stream implementation that doesn't require continuous address space for internal array allocation (i.e. a linked list of memory streams); this way, at least on 64-bit environments, out of memory exceptions should no longer be an issue. Con: extra work, more room for mistakes. So how do FileStream vs MemoryStream read/writes behave in terms of disk access and memory caching, i.e. data size/performance balance. I would expect that as long as enough RAM is available, FileStream would internally read/write from memory (cache) anyway, and virtual memory would take care of the rest. But I don't know how often FileStream will explicitly access a disk when being written to. Any help would be appreciated.

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  • How to manipulate file paths intelligently in .Net 3.0?

    - by Hamish Grubijan
    Scenario: I am maintaining a function which helps with an install - copies files from PathPart1/pending_install/PathPart2/fileName to PathPart1/PathPart2/fileName. It seems that String.Replace() and Path.Combine() do not play well together. The code is below. I added this section: // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); in order to take care of a bug (code is sensitive to a constant @"pending_install\" vs @"pending_install" which I did not like and changed (long story, but there was a good opportunity for constant reuse). Now the whole function: //You want to uncompress only the files downloaded. Not every file in the dest directory. private void UncompressFiles() { string strSrcDir = _application.Client.TempDir; ArrayList arrFiles = new ArrayList(); GetAllCompressedFiles(ref arrFiles, strSrcDir); IEnumerator enumer = arrFiles.GetEnumerator(); while (enumer.MoveNext()) { string strDestFile = enumer.Current.ToString().Replace(_application.Client.TempDir, String.Empty); // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); strDestFile = Path.Combine(_application.Client.BaseDir, strDestFile); strDestFile = strDestFile.Replace(Path.GetExtension(strDestFile), String.Empty); ZSharpLib.ZipExtractor.ExtractZip(enumer.Current.ToString(), strDestFile); FileUtility.DeleteFile(enumer.Current.ToString()); } } Please do not laugh at the use of ArrayList and the way it is being iterated - it was pioneered by a C++ coder during a .Net 1.1 era. I will change it. What I am interested in: what is a better way of replacing PathPart1/pending_install/PathPart2/fileName with PathPart1/PathPart2/fileName within the current code. Note that _application.Client.TempDir is just _application.Client.BaseDir + @"\pending_install". While there are many ways to improve the code, I am mainly concerned with the part which has to do with String.Replace(...) and Path.Combine(,). I do not want to make changes outside of this function. I wish Path.Combine(,) took an optional bool flag, but it does not. So ... given my constraints, how can I rework this so that it starts to sucks less? Thanks!

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