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  • Why does Scala require functions to have explicit return type?

    - by garbage collection
    I recently began learning to program in Scala, and it's been fun so far. I really like the ability to declare functions within another function which just seems to intuitive thing to do. One pet peeve I have about Scala is the fact that Scala requires explicit return type in its functions. And I feel like this hinders on expressiveness of the language. Also it's just difficult to program with that requirement. Maybe it's because I come from Javascript and Ruby comfort zone. But for a language like Scala which will have tons of connected functions in an application, I cannot conceive how I brainstorm in my head exactly what type the particular function I am writing should return with recursions after recursions. This requirement of explicit return type declaration on functions, do not bother me for languages like Java and C++. Recursions in Java and C++, when they did happen, often were dealt with 2 to 3 functions max. Never several functions chained up together like Scala. So I guess I'm wondering if there is a good reason why Scala should have the requirement of functions having explicit return type?

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  • When to write an explicit return statement in Groovy?

    - by Roland Schneider
    At the moment I am working on a Groovy/Grails project (which I'm quite new in) and I wonder whether it is good practice to omit the return keyword in Groovy methods. As far as I know you have to explicitly insert the keyword i.e. for guard clauses, so should one use it also everywhere else? In my opinion the additional return keyword increases readability. Or is it something you just have to get used to? What is your experience with that topic? Some examples: def foo(boolean bar) { // Not consistent if (bar) { return positiveBar() } negativeBar() } def foo2() { // Special Grails example def entitiy = new Entity(foo: 'Foo', bar: 'Bar') entity.save flush: true // Looks strange to me this way entity }

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • What are the default return values for operator< and operator[] in C++ (Visual Studio 6)?

    - by DustOff
    I've inherited a large Visual Studio 6 C++ project that needs to be translated for VS2005. Some of the classes defined operator< and operator[], but don't specify return types in the declarations. VS6 allows this, but not VS2005. I am aware that the C standard specifies that the default return type for normal functions is int, and I assumed VS6 might have been following that, but would this apply to C++ operators as well? Or could VS6 figure out the return type on its own? For example, the code defines a custom string class like this: class String { char arr[16]; public: operator<(const String& other) { return something1 < something2; } operator[](int index) { return arr[index]; } }; Would VS6 have simply put the return types for both as int, or would it have been smart enough to figure out that operator[] should return a char and operator< should return a bool (and not convert both results to int all the time)? Of course I have to add return types to make this code VS2005 C++ compliant, but I want to make sure to specify the same type as before, as to not immediately change program behavior (we're going for compatibility at the moment; we'll standardize things later).

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  • Is return-type-(only)-polymorphism in Haskell a good thing?

    - by dainichi
    One thing that I've never quite come to terms with in Haskell is how you can have polymorphic constants and functions whose return type cannot be determined by their input type, like class Foo a where foo::Int -> a Some of the reasons that I do not like this: Referential transparency: "In Haskell, given the same input, a function will always return the same output", but is that really true? read "3" return 3 when used in an Int context, but throws an error when used in a, say, (Int,Int) context. Yes, you can argue that read is also taking a type parameter, but the implicitness of the type parameter makes it lose some of its beauty in my opinion. Monomorphism restriction: One of the most annoying things about Haskell. Correct me if I'm wrong, but the whole reason for the MR is that computation that looks shared might not be because the type parameter is implicit. Type defaulting: Again one of the most annoying things about Haskell. Happens e.g. if you pass the result of functions polymorphic in their output to functions polymorphic in their input. Again, correct me if I'm wrong, but this would not be necessary without functions whose return type cannot be determined by their input type (and polymorphic constants). So my question is (running the risk of being stamped as a "discussion quesion"): Would it be possible to create a Haskell-like language where the type checker disallows these kinds of definitions? If so, what would be the benefits/disadvantages of that restriction? I can see some immediate problems: If, say, 2 only had the type Integer, 2/3 wouldn't type check anymore with the current definition of /. But in this case, I think type classes with functional dependencies could come to the rescue (yes, I know that this is an extension). Furthermore, I think it is a lot more intuitive to have functions that can take different input types, than to have functions that are restricted in their input types, but we just pass polymorphic values to them. The typing of values like [] and Nothing seems to me like a tougher nut to crack. I haven't thought of a good way to handle them. I doubt I am the first person to have had thoughts like these. Does anybody have links to good discussions about this Haskell design decision and the pros/cons of it?

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  • Why does division yield a vastly different result than multiplication by a fraction in floating points.

    - by Avram
    I understand why floating point numbers can't be compared, and know about the mantissa and exponent binary representation, but I'm no expert and today I came across something I don't get: Namely lets say you have something like: float denominator, numerator, resultone, resulttwo; resultone = numerator / denominator; float buff = 1 / denominator; resulttwo = numerator * buff; To my knowledge different flops can yield different results and this is not unusual. But in some edge cases these two results seem to be vastly different. To be more specific in my GLSL code calculating the Beckmann facet slope distribution for the Cook-Torrance lighitng model: float a = 1 / (facetSlopeRMS * facetSlopeRMS * pow(clampedCosHalfNormal, 4)); float b = clampedCosHalfNormal * clampedCosHalfNormal - 1.0; float c = facetSlopeRMS * facetSlopeRMS * clampedCosHalfNormal * clampedCosHalfNormal; facetSlopeDistribution = a * exp(b/c); yields very very different results to float a = (facetSlopeRMS * facetSlopeRMS * pow(clampedCosHalfNormal, 4)); facetDlopeDistribution = exp(b/c) / a; Why does it? The second form of the expression is problematic. If I say try to add the second form of the expression to a color I get blacks, even though the expression should always evaluate to a positive number. Am I getting an infinity? A NaN? if so why?

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  • Why Enumerable.Range is faster than a direct yield loop?

    - by Morgan Cheng
    Below code is checking performance of three different ways to do same solution. public static void Main(string[] args) { // for loop { Stopwatch sw = Stopwatch.StartNew(); int accumulator = 0; for (int i = 1; i <= 100000000; ++i) { accumulator += i; } sw.Stop(); Console.WriteLine("time = {0}; result = {1}", sw.ElapsedMilliseconds, accumulator); } //Enumerable.Range { Stopwatch sw = Stopwatch.StartNew(); var ret = Enumerable.Range(1, 100000000).Aggregate(0, (accumulator, n) => accumulator + n); sw.Stop(); Console.WriteLine("time = {0}; result = {1}", sw.ElapsedMilliseconds, ret); } //self-made IEnumerable<int> { Stopwatch sw = Stopwatch.StartNew(); var ret = GetIntRange(1, 100000000).Aggregate(0, (accumulator, n) => accumulator + n); sw.Stop(); Console.WriteLine("time = {0}; result = {1}", sw.ElapsedMilliseconds, ret); } } private static IEnumerable<int> GetIntRange(int start, int count) { int end = start + count; for (int i = start; i < end; ++i) { yield return i; } } } The result is like this: time = 306; result = 987459712 time = 1301; result = 987459712 time = 2860; result = 987459712 It is not surprising that "for loop" is faster than the other two solutions, because Enumerable.Aggregate takes more method invocations. However, it really surprises that "Enumerable.Range" is faster than the "self-made IEnumerable". I thought that Enumerable.Range will take more overhead than the simple GetIntRange method. What is the possible reason for this?

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  • Iterator blocks and inheritance.

    - by Dave Van den Eynde
    Given a base class with the following interface: public class Base { public virtual IEnumerable<string> GetListOfStuff() { yield return "First"; yield return "Second"; yield return "Third"; } } I want to make a derived class that overrides the method, and adds its own stuff, like so: public class Derived : Base { public override IEnumerable<string> GetListOfStuff() { foreach (string s in base.GetListOfStuff()) { yield return s; } yield return "Fourth"; yield return "Fifth"; } } However, I'm greeted with a warning that "access to a member through a base keyword from an iterator cannot be verified". What's the accepted solution to this problem then?

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  • return char1 + char2? Isn't it possible?

    - by pocoa
    I'm trying to return a string from a function. Which basically adds some chars together and return the string representation. string toString() { char c1, c2, c3; // some code here return c1 + c2; // Error: invalid conversion from `char' to `const char*' } it is possible to return boolean values like return c1 == 'x'. Isn't it possible to return string values? I know that it is possible to it like this: string result; result.append(c1, c2); return result; I'm new to C++ so I thought that there must be more elegant solution around.

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  • JGoodies HashMap

    - by JohnMcClane
    Hi, I'm trying to build a chart program using presentation model. Using JGoodies for data binding was relatively easy for simple types like strings or numbers. But I can't figure out how to use it on a hashmap. I'll try to explain how the chart works and what my problem is: A chart consists of DataSeries, a DataSeries consists of DataPoints. I want to have a data model and to be able to use different views on the same model (e.g. bar chart, pie chart,...). Each of them consists of three classes. For example: DataPointModel: holds the data model (value, label, category) DataPointViewModel: extends JGoodies PresentationModel. wraps around DataPointModel and holds view properties like font and color. DataPoint: abstract class, extends JComponent. Different Views must subclass and implement their own ui. Binding and creating the data model was easy, but i don't know how to bind my data series model. package at.onscreen.chart; import java.beans.PropertyChangeListener; import java.beans.PropertyChangeSupport; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; public class DataSeriesModel { public static String PROPERTY_DATAPOINT = "dataPoint"; public static String PROPERTY_DATAPOINTS = "dataPoints"; public static String PROPERTY_LABEL = "label"; public static String PROPERTY_MAXVALUE = "maxValue"; /** * holds the data points */ private HashMap dataPoints; /** * the label for the data series */ private String label; /** * the maximum data point value */ private Double maxValue; /** * the model supports property change notification */ private PropertyChangeSupport propertyChangeSupport; /** * default constructor */ public DataSeriesModel() { this.maxValue = Double.valueOf(0); this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); } /** * constructor * @param label - the series label */ public DataSeriesModel(String label) { this.dataPoints = new HashMap(); this.maxValue = Double.valueOf(0); this.label = label; this.propertyChangeSupport = new PropertyChangeSupport(this); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeriesModel(String label, DataPoint[] dataPoints) { this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); this.maxValue = Double.valueOf(0); this.label = label; for (int i = 0; i < dataPoints.length; i++) { this.addDataPoint(dataPoints[i]); } } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeriesModel(String label, Collection dataPoints) { this.dataPoints = new HashMap(); this.propertyChangeSupport = new PropertyChangeSupport(this); this.maxValue = Double.valueOf(0); this.label = label; for (Iterator it = dataPoints.iterator(); it.hasNext();) { this.addDataPoint(it.next()); } } /** * adds a new data point to the series. if the series contains a data point with same id, it will be replaced by the new one. * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { String category = dataPoint.getCategory(); DataPoint oldDataPoint = this.getDataPoint(category); this.dataPoints.put(category, dataPoint); this.setMaxValue(Math.max(this.maxValue, dataPoint.getValue())); this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINT, oldDataPoint, dataPoint); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.dataPoints.get(category); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { DataPoint dataPoint = this.getDataPoint(category); this.dataPoints.remove(category); if (dataPoint != null) { if (dataPoint.getValue() == this.getMaxValue()) { Double maxValue = Double.valueOf(0); for (Iterator it = this.iterator(); it.hasNext();) { DataPoint itDataPoint = it.next(); maxValue = Math.max(itDataPoint.getValue(), maxValue); } this.setMaxValue(maxValue); } } this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINT, dataPoint, null); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.setMaxValue(Double.valueOf(0)); this.dataPoints.clear(); this.propertyChangeSupport.firePropertyChange(PROPERTY_DATAPOINTS, this.getDataPoints(), null); } /** * returns the maximum of all data point values * @return the maximum of all data points */ public Double getMaxValue() { return this.maxValue; } /** * sets the max value * @param maxValue - the max value */ protected void setMaxValue(Double maxValue) { Double oldMaxValue = this.getMaxValue(); this.maxValue = maxValue; this.propertyChangeSupport.firePropertyChange(PROPERTY_MAXVALUE, oldMaxValue, maxValue); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.dataPoints.containsKey(category); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.label; } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.dataPoints.values().iterator(); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.dataPoints.values(); } /** * returns the number of data points in the series * @return the number of data points */ public int getSize() { return this.dataPoints.size(); } /** * adds a PropertyChangeListener * @param listener - the listener */ public void addPropertyChangeListener(PropertyChangeListener listener) { this.propertyChangeSupport.addPropertyChangeListener(listener); } /** * removes a PropertyChangeListener * @param listener - the listener */ public void removePropertyChangeListener(PropertyChangeListener listener) { this.propertyChangeSupport.removePropertyChangeListener(listener); } } package at.onscreen.chart; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.Iterator; import com.jgoodies.binding.PresentationModel; public class DataSeriesViewModel extends PresentationModel { /** * default constructor */ public DataSeriesViewModel() { super(new DataSeriesModel()); } /** * constructor * @param label - the series label */ public DataSeriesViewModel(String label) { super(new DataSeriesModel(label)); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeriesViewModel(String label, DataPoint[] dataPoints) { super(new DataSeriesModel(label, dataPoints)); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeriesViewModel(String label, Collection dataPoints) { super(new DataSeriesModel(label, dataPoints)); } /** * full constructor * @param model - the data series model */ public DataSeriesViewModel(DataSeriesModel model) { super(model); } /** * adds a data point to the series * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { this.getBean().addDataPoint(dataPoint); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.getBean().contains(category); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.getBean().getDataPoint(category); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.getBean().getDataPoints(); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.getBean().getLabel(); } /** * sets the max value * @param maxValue - the max value */ public Double getMaxValue() { return this.getBean().getMaxValue(); } /** * returns the number of data points in the series * @return the number of data points */ public int getSize() { return this.getBean().getSize(); } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.getBean().iterator(); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.getBean().removeAll(); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { this.getBean().removeDataPoint(category); } } package at.onscreen.chart; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.beans.PropertyVetoException; import java.util.Collection; import java.util.Iterator; import javax.swing.JComponent; public abstract class DataSeries extends JComponent implements PropertyChangeListener { /** * the model */ private DataSeriesViewModel model; /** * default constructor */ public DataSeries() { this.model = new DataSeriesViewModel(); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * constructor * @param label - the series label */ public DataSeries(String label) { this.model = new DataSeriesViewModel(label); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public DataSeries(String label, DataPoint[] dataPoints) { this.model = new DataSeriesViewModel(label, dataPoints); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public DataSeries(String label, Collection dataPoints) { this.model = new DataSeriesViewModel(label, dataPoints); this.model.addPropertyChangeListener(this); this.createComponents(); } /** * full constructor * @param model - the model */ public DataSeries(DataSeriesViewModel model) { this.model = model; this.model.addPropertyChangeListener(this); this.createComponents(); } /** * creates, binds and configures UI components. * data point properties can be created here as components or be painted in paintComponent. */ protected abstract void createComponents(); @Override public void propertyChange(PropertyChangeEvent evt) { this.repaint(); } /** * adds a data point to the series * @param dataPoint - the data point */ public void addDataPoint(DataPoint dataPoint) { this.model.addDataPoint(dataPoint); } /** * returns true if there is a data point with given category * @param category - the data point category * @return true if there is a data point with given category, otherwise false */ public boolean contains(String category) { return this.model.contains(category); } /** * returns the data point with given id or null if not found * @param uid - the id of the data point * @return the data point or null if there is no such point in the table */ public DataPoint getDataPoint(String category) { return this.model.getDataPoint(category); } /** * returns a collection of the data points. the collection supports removal, but does not support adding of data points. * @return a collection of data points */ public Collection getDataPoints() { return this.model.getDataPoints(); } /** * returns the label for the series * @return the label for the series */ public String getLabel() { return this.model.getLabel(); } /** * sets the max value * @param maxValue - the max value */ public Double getMaxValue() { return this.model.getMaxValue(); } /** * returns the number of data points in the series * @return the number of data points */ public int getDataPointCount() { return this.model.getSize(); } /** * returns an iterator over the data points * @return an iterator over the data points */ public Iterator iterator() { return this.model.iterator(); } /** * removes all data points from the series * @throws PropertyVetoException */ public void removeAll() { this.model.removeAll(); } /** * removes the data point with given id from the series, if present * @param category - the data point to remove */ public void removeDataPoint(String category) { this.model.removeDataPoint(category); } /** * returns the data series view model * @return - the data series view model */ public DataSeriesViewModel getViewModel() { return this.model; } /** * returns the data series model * @return - the data series model */ public DataSeriesModel getModel() { return this.model.getBean(); } } package at.onscreen.chart.builder; import java.util.Collection; import net.miginfocom.swing.MigLayout; import at.onscreen.chart.DataPoint; import at.onscreen.chart.DataSeries; import at.onscreen.chart.DataSeriesViewModel; public class BuilderDataSeries extends DataSeries { /** * default constructor */ public BuilderDataSeries() { super(); } /** * constructor * @param label - the series label */ public BuilderDataSeries(String label) { super(label); } /** * full constructor * @param label - the series label * @param dataPoints - an array of data points */ public BuilderDataSeries(String label, DataPoint[] dataPoints) { super(label, dataPoints); } /** * full constructor * @param label - the series label * @param dataPoints - a collection of data points */ public BuilderDataSeries(String label, Collection dataPoints) { super(label, dataPoints); } /** * full constructor * @param model - the model */ public BuilderDataSeries(DataSeriesViewModel model) { super(model); } @Override protected void createComponents() { this.setLayout(new MigLayout()); /* * * I want to add a new BuilderDataPoint for each data point in the model. * I want the BuilderDataPoints to be synchronized with the model. * e.g. when a data point is removed from the model, the BuilderDataPoint shall be removed * from the BuilderDataSeries * */ } } package at.onscreen.chart.builder; import javax.swing.JFormattedTextField; import javax.swing.JTextField; import at.onscreen.chart.DataPoint; import at.onscreen.chart.DataPointModel; import at.onscreen.chart.DataPointViewModel; import at.onscreen.chart.ValueFormat; import com.jgoodies.binding.adapter.BasicComponentFactory; import com.jgoodies.binding.beans.BeanAdapter; public class BuilderDataPoint extends DataPoint { /** * default constructor */ public BuilderDataPoint() { super(); } /** * constructor * @param category - the category */ public BuilderDataPoint(String category) { super(category); } /** * constructor * @param value - the value * @param label - the label * @param category - the category */ public BuilderDataPoint(Double value, String label, String category) { super(value, label, category); } /** * full constructor * @param model - the model */ public BuilderDataPoint(DataPointViewModel model) { super(model); } @Override protected void createComponents() { BeanAdapter beanAdapter = new BeanAdapter(this.getModel(), true); ValueFormat format = new ValueFormat(); JFormattedTextField value = BasicComponentFactory.createFormattedTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_VALUE), format); this.add(value, "w 80, growx, wrap"); JTextField label = BasicComponentFactory.createTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_LABEL)); this.add(label, "growx, wrap"); JTextField category = BasicComponentFactory.createTextField(beanAdapter.getValueModel(DataPointModel.PROPERTY_CATEGORY)); this.add(category, "growx, wrap"); } } To sum it up: I need to know how to bind a hash map property to JComponent.components property. JGoodies is in my opinion not very well documented, I spent a long time searching through the internet, but I did not find any solution to my problem. Hope you can help me.

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  • Does using cat5e cables yield any disadvantages in combination with cat6/cat6a network?

    - by agent154
    If I were to have a fully compliant cat6 or cat6a network running through my walls... that is to say, wires and jacks... What would be the concequence of plugging a cat5e wire into one of the jacks? I'm assuming that it would still run at cat5e standards, but obviously not cat6/6a standards because the whole connection is not cat6. I only ask because it seems silly to me to make a bunch of cat6 patch cables for connections that don't really matter, like standard desktop computers and other equipment. Or will doing so hamper the whole network?

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  • Silverlight for Windows Embedded tutorial (step 6)

    - by Valter Minute
    In this tutorial step we will develop a very simple clock application that may be used as a screensaver on our devices and will allow us to discover a new feature of Silverlight for Windows Embedded (transforms) and how to use an “old” feature of Windows CE (timers) inside a Silverlight for Windows Embedded application. Let’s start with some XAML, as usual: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Width="640" Height="480" FontSize="18" x:Name="Clock">   <Canvas x:Name="LayoutRoot" Background="#FF000000"> <Grid Height="24" Width="150" Canvas.Left="320" Canvas.Top="234" x:Name="SecondsHand" Background="#FFFF0000"> <TextBlock Text="Seconds" TextWrapping="Wrap" Width="50" HorizontalAlignment="Right" VerticalAlignment="Center" x:Name="SecondsText" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> <Grid Height="24" x:Name="MinutesHand" Width="100" Background="#FF00FF00" Canvas.Left="320" Canvas.Top="234"> <TextBlock HorizontalAlignment="Right" x:Name="MinutesText" VerticalAlignment="Center" Width="50" Text="Minutes" TextWrapping="Wrap" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> <Grid Height="24" x:Name="HoursHand" Width="50" Background="#FF0000FF" Canvas.Left="320" Canvas.Top="234"> <TextBlock HorizontalAlignment="Right" x:Name="HoursText" VerticalAlignment="Center" Width="50" Text="Hours" TextWrapping="Wrap" Foreground="#FFFFFFFF" TextAlignment="Right" Margin="2,2,2,2"/> </Grid> </Canvas> </UserControl> This XAML file defines three grid panels, one for each hand of our clock (we are implementing an analog clock using one of the most advanced technologies of the digital world… how cool is that?). Inside each hand we put a TextBlock that will be used to display the current hour, minute, second inside the dial (you can’t do that on plain old analog clocks, but it looks nice). As usual we use XAML2CPP to generate the boring part of our code. We declare a class named “Clock” and derives from the TClock template that XAML2CPP has declared for us. class Clock : public TClock<Clock> { ... }; Our WinMain function is more or less the same we used in all the previous samples. It initializes the XAML runtime, create an instance of our class, initialize it and shows it as a dialog: int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow) { if (!XamlRuntimeInitialize()) return -1;   HRESULT retcode;   IXRApplicationPtr app; if (FAILED(retcode=GetXRApplicationInstance(&app))) return -1; Clock clock;   if (FAILED(clock.Init(hInstance,app))) return -1;     UINT exitcode;   if (FAILED(clock.GetVisualHost()->StartDialog(&exitcode))) return -1;   return exitcode; } Silverlight for Windows Embedded provides a lot of features to implement our UI, but it does not provide timers. How we can update our clock if we don’t have a timer feature? We just use plain old Windows timers, as we do in “regular” Windows CE applications! To use a timer in WinCE we should declare an id for it: #define IDT_CLOCKUPDATE 0x12341234 We also need an HWND that will be used to receive WM_TIMER messages. Our Silverlight for Windows Embedded page is “hosted” inside a GWES Window and we can retrieve its handle using the GetContainerHWND function of our VisualHost object. Let’s see how this is implemented inside our Clock class’ Init method: HRESULT Init(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode;   if (FAILED(retcode=TClock<Clock>::Init(hInstance,app))) return retcode;   // create the timer user to update the clock HWND clockhwnd;   if (FAILED(GetVisualHost()->GetContainerHWND(&clockhwnd))) return -1;   timer=SetTimer(clockhwnd,IDT_CLOCKUPDATE,1000,NULL); return 0; } We use SetTimer to create a new timer and GWES will send a WM_TIMER to our window every second, giving us a chance to update our clock. That sounds great… but how could we handle the WM_TIMER message if we didn’t implement a window procedure for our window? We have to move a step back and look how a visual host is created. This code is generated by XAML2CPP and is inside xaml2cppbase.h: virtual HRESULT CreateHost(HINSTANCE hInstance,IXRApplication* app) { HRESULT retcode; XRWindowCreateParams wp;   ZeroMemory(&wp, sizeof(XRWindowCreateParams)); InitWindowParms(&wp);   XRXamlSource xamlsrc;   SetXAMLSource(hInstance,&xamlsrc); if (FAILED(retcode=app->CreateHostFromXaml(&xamlsrc, &wp, &vhost))) return retcode;   if (FAILED(retcode=vhost->GetRootElement(&root))) return retcode; return S_OK; } As you can see the CreateHostFromXaml function of IXRApplication accepts a structure named XRWindowCreateParams that control how the “plain old” GWES Window is created by the runtime. This structure is initialized inside the InitWindowParm method: // Initializes Windows parameters, can be overridden in the user class to change its appearance virtual void InitWindowParms(XRWindowCreateParams* wp) { wp->Style = WS_OVERLAPPED; wp->pTitle = windowtitle; wp->Left = 0; wp->Top = 0; } This method set up the window style, title and position. But the XRWindowCreateParams contains also other fields and, since the function is declared as virtual, we could initialize them inside our version of InitWindowParms: // add hook procedure to the standard windows creation parms virtual void InitWindowParms(XRWindowCreateParams* wp) { TClock<Clock>::InitWindowParms(wp);   wp->pHookProc=StaticHostHookProc; wp->pvUserParam=this; } This method calls the base class implementation (useful to not having to re-write some code, did I told you that I’m quite lazy?) and then initializes the pHookProc and pvUserParam members of the XRWindowsCreateParams structure. Those members will allow us to install a “hook” procedure that will be called each time the GWES window “hosting” our Silverlight for Windows Embedded UI receives a message. We can declare a hook procedure inside our Clock class: // static hook procedure static BOOL CALLBACK StaticHostHookProc(VOID* pv,HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { ... } You should notice two things here. First that the function is declared as static. This is required because a non-static function has a “hidden” parameters, that is the “this” pointer of our object. Having an extra parameter is not allowed for the type defined for the pHookProc member of the XRWindowsCreateParams struct and so we should implement our hook procedure as static. But in a static procedure we will not have a this pointer. How could we access the data member of our class? Here’s the second thing to notice. We initialized also the pvUserParam of the XRWindowsCreateParams struct. We set it to our this pointer. This value will be passed as the first parameter of the hook procedure. In this way we can retrieve our this pointer and use it to call a non-static version of our hook procedure: // static hook procedure static BOOL CALLBACK StaticHostHookProc(VOID* pv,HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { return ((Clock*)pv)->HostHookProc(hwnd,Msg,wParam,lParam,pRetVal); } Inside our non-static hook procedure we will have access to our this pointer and we will be able to update our clock: // hook procedure (handles timers) BOOL HostHookProc(HWND hwnd,UINT Msg,WPARAM wParam,LPARAM lParam,LRESULT* pRetVal) { switch (Msg) { case WM_TIMER: if (wParam==IDT_CLOCKUPDATE) UpdateClock(); *pRetVal=0; return TRUE; } return FALSE; } The UpdateClock member function will update the text inside our TextBlocks and rotate the hands to reflect current time: // udates Hands positions and labels HRESULT UpdateClock() { SYSTEMTIME time; HRESULT retcode;   GetLocalTime(&time);   //updates the text fields TCHAR timebuffer[32];   _itow(time.wSecond,timebuffer,10);   SecondsText->SetText(timebuffer);   _itow(time.wMinute,timebuffer,10);   MinutesText->SetText(timebuffer);   _itow(time.wHour,timebuffer,10);   HoursText->SetText(timebuffer);   if (FAILED(retcode=RotateHand(((float)time.wSecond)*6-90,SecondsHand))) return retcode;   if (FAILED(retcode=RotateHand(((float)time.wMinute)*6-90,MinutesHand))) return retcode;   if (FAILED(retcode=RotateHand(((float)(time.wHour%12))*30-90,HoursHand))) return retcode;   return S_OK; } The function retrieves current time, convert hours, minutes and seconds to strings and display those strings inside the three TextBlocks that we put inside our clock hands. Then it rotates the hands to position them at the right angle (angles are in degrees and we have to subtract 90 degrees because 0 degrees means horizontal on Silverlight for Windows Embedded and usually a clock 0 is in the top position of the dial. The code of the RotateHand function uses transforms to rotate our clock hands on the screen: // rotates a Hand HRESULT RotateHand(float angle,IXRFrameworkElement* Hand) { HRESULT retcode; IXRRotateTransformPtr rotatetransform; IXRApplicationPtr app;   if (FAILED(retcode=GetXRApplicationInstance(&app))) return retcode;   if (FAILED(retcode=app->CreateObject(IID_IXRRotateTransform,&rotatetransform))) return retcode;     if (FAILED(retcode=rotatetransform->SetAngle(angle))) return retcode;   if (FAILED(retcode=rotatetransform->SetCenterX(0.0))) return retcode;   float height;   if (FAILED(retcode==Hand->GetActualHeight(&height))) return retcode;   if (FAILED(retcode=rotatetransform->SetCenterY(height/2))) return retcode; if (FAILED(retcode=Hand->SetRenderTransform(rotatetransform))) return retcode;   return S_OK; } It creates a IXRotateTransform object, set its rotation angle and origin (the default origin is at the top-left corner of our Grid panel, we move it in the vertical center to keep the hand rotating around a single point in a more “clock like” way. Then we can apply the transform to our UI object using SetRenderTransform. Every UI element (derived from IXRFrameworkElement) can be rotated! And using different subclasses of IXRTransform also moved, scaled, skewed and distorted in many ways. You can also concatenate multiple transforms and apply them at once suing a IXRTransformGroup object. The XAML engine uses vector graphics and object will not look “pixelated” when they are rotated or scaled. As usual you can download the code here: http://cid-9b7b0aefe3514dc5.skydrive.live.com/self.aspx/.Public/Clock.zip If you read up to (down to?) this point you seem to be interested in Silverlight for Windows Embedded. If you want me to discuss some specific topic, please feel free to point it out in the comments! Technorati Tags: Silverlight for Windows Embedded,Windows CE

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  • NHibernate IUserType convert nullable DateTime to DB not-null value

    - by barakbbn
    I have legacy DB that store dates that means no-date as 9999-21-31, The column Till_Date is of type DateTime not-null="true". in the application i want to build persisted class that represent no-date as null, So i used nullable DateTime in C# //public DateTime? TillDate {get; set; } I created IUserType that knows to convert the entity null value to DB 9999-12-31 but it seems that NHibernate doesn't call SafeNullGet, SafeNullSet on my IUserType when the entity value is null, and report a null is used for not-null column. I tried to by-pass it by mapping the column as not-null="false" (changed only the mapping file, not the DB) but it still didn't help, only now it tries to insert the null value to the DB and get ADOException. Any knowledge if NHibernate doesn't support IUseType that convert null to not-null values? Thanks //Implementation public class NullableDateTimeToNotNullUserType : IUserType { private static readonly DateTime MaxDate = new DateTime(9999, 12, 31); public new bool Equals(object x, object y) { //This didn't work as well if (ReferenceEquals(x, y)) return true; //if(x == null && y == null) return false; if (x == null || y == null) return false; return x.Equals(y); } public int GetHashCode(object x) { return x == null ? 0 : x.GetHashCode(); } public object NullSafeGet(IDataReader rs, string[] names, object owner) { var value = rs.GetDateTime(rs.GetOrdinal(names[0])); return (value == MaxDate)? null : value; } public void NullSafeSet(IDbCommand cmd, object value, int index) { var dateValue = (DateTime?)value; var dbValue = (dateValue.HasValue) ? dateValue.Value : MaxDate; ((IDataParameter)cmd.Parameters[index]).Value = dbValue; } public object DeepCopy(object value) { return value; } public object Replace(object original, object target, object owner) { return original; } public object Assemble(object cached, object owner) { return cached; } public object Disassemble(object value) { return value; } public SqlType[] SqlTypes { get { return new[] { NHibernateUtil.DateTime.SqlType }; } } public Type ReturnedType { get { return typeof(DateTime?); } } public bool IsMutable { get { return false; } } } } //Final Implementation with fixes. make the column mapping in hbm.xml not-null="false" public class NullableDateTimeToNotNullUserType : IUserType { private static readonly DateTime MaxDate = new DateTime(9999, 12, 31); public new bool Equals(object x, object y) { //This didn't work as well if (ReferenceEquals(x, y)) return true; //if(x == null && y == null) return false; if (x == null || y == null) return false; return x.Equals(y); } public int GetHashCode(object x) { return x == null ? 0 : x.GetHashCode(); } public object NullSafeGet(IDataReader rs, string[] names, object owner) { var value = NHibernateUtil.Date.NullSafeGet(rs, names[0]); return (value == MaxDate)? default(DateTime?) : value; } public void NullSafeSet(IDbCommand cmd, object value, int index) { var dateValue = (DateTime?)value; var dbValue = (dateValue.HasValue) ? dateValue.Value : MaxDate; NHibernateUtil.Date.NullSafeSet(cmd, valueToSet, index); } public object DeepCopy(object value) { return value; } public object Replace(object original, object target, object owner) { return original; } public object Assemble(object cached, object owner) { return cached; } public object Disassemble(object value) { return value; } public SqlType[] SqlTypes { get { return new[] { NHibernateUtil.DateTime.SqlType }; } } public Type ReturnedType { get { return typeof(DateTime?); } } public bool IsMutable { get { return false; } } } }

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  • ActiveRecord + CodeIgniter - Return single value from query, not in array form.

    - by txmail
    Say you construct an activerecord query that will always just return a single value, how do you just address that single value instead of getting an array in return? For instance I am using an ActiveRecord query to return the SUM of a single column, it will only return this one single SUM, instead of having to parse the array is there a way to assign the value as a function return equal to that value instead of getting an array?

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  • Does waitpid yield valid status information for a child process that has already exited?

    - by dtrebbien
    If I fork a child process, and the child process exits before the parent even calls waitpid, then is the exit status information that is set by waitpid still valid? If so, when does it become not valid; i.e., how do I ensure that I can call waitpid on the child pid and continue to get valid exit status information after an arbitrary amount of time, and how do I "clean up" (tell the OS that I am no longer interested in the exit status information for the finished child process)? I was playing around with the following code, and it appears that the exit status information is valid for at least a few seconds after the child finishes, but I do not know for how long or how to inform the OS that I won't be calling waitpid again: #include <assert.h> #include <pthread.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/wait.h> int main() { pid_t pid = fork(); if (pid < 0) { fprintf(stderr, "Failed to fork\n"); return EXIT_FAILURE; } else if (pid == 0) { // code for child process _exit(17); } else { // code for parent sleep(3); int status; waitpid(pid, &status, 0); waitpid(pid, &status, 0); // call `waitpid` again just to see if the first call had an effect assert(WIFEXITED(status)); assert(WEXITSTATUS(status) == 17); } return EXIT_SUCCESS; }

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  • Where can these be posted besides the Python Cookbook?

    - by Noctis Skytower
    Whitespace Assembler #! /usr/bin/env python """Assembler.py Compiles a program from "Assembly" folder into "Program" folder. Can be executed directly by double-click or on the command line. Give name of *.WSA file without extension (example: stack_calc).""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 3 $' ################################################################################ import string from Interpreter import INS, MNEMONIC ################################################################################ def parse(code): program = [] process_virtual(program, code) process_control(program) return tuple(program) def process_virtual(program, code): for line, text in enumerate(code.split('\n')): if not text or text[0] == '#': continue if text.startswith('part '): parse_part(program, line, text[5:]) elif text.startswith(' '): parse_code(program, line, text[5:]) else: syntax_error(line) def syntax_error(line): raise SyntaxError('Line ' + str(line + 1)) ################################################################################ def process_control(program): parts = get_parts(program) names = dict(pair for pair in zip(parts, generate_index())) correct_control(program, names) def get_parts(program): parts = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins if ins == INS.PART: if arg in parts: raise NameError('Part definition was found twice: ' + arg) parts.append(arg) return parts def generate_index(): index = 1 while True: yield index index *= -1 if index > 0: index += 1 def correct_control(program, names): for index, ins in enumerate(program): if isinstance(ins, tuple): ins, arg = ins if ins in HAS_LABEL: if arg not in names: raise NameError('Part definition was never found: ' + arg) program[index] = (ins, names[arg]) ################################################################################ def parse_part(program, line, text): if not valid_label(text): syntax_error(line) program.append((INS.PART, text)) def valid_label(text): if not between_quotes(text): return False label = text[1:-1] if not valid_name(label): return False return True def between_quotes(text): if len(text) < 3: return False if text.count('"') != 2: return False if text[0] != '"' or text[-1] != '"': return False return True def valid_name(label): valid_characters = string.ascii_letters + string.digits + '_' valid_set = frozenset(valid_characters) label_set = frozenset(label) if len(label_set - valid_set) != 0: return False return True ################################################################################ from Interpreter import HAS_LABEL, Program NO_ARGS = Program.NO_ARGS HAS_ARG = Program.HAS_ARG TWO_WAY = tuple(set(NO_ARGS) & set(HAS_ARG)) ################################################################################ def parse_code(program, line, text): for ins, word in enumerate(MNEMONIC): if text.startswith(word): check_code(program, line, text[len(word):], ins) break else: syntax_error(line) def check_code(program, line, text, ins): if ins in TWO_WAY: if text: number = parse_number(line, text) program.append((ins, number)) else: program.append(ins) elif ins in HAS_LABEL: text = parse_label(line, text) program.append((ins, text)) elif ins in HAS_ARG: number = parse_number(line, text) program.append((ins, number)) elif ins in NO_ARGS: if text: syntax_error(line) program.append(ins) else: syntax_error(line) def parse_label(line, text): if not text or text[0] != ' ': syntax_error(line) text = text[1:] if not valid_label(text): syntax_error(line) return text ################################################################################ def parse_number(line, text): if not valid_number(text): syntax_error(line) return int(text) def valid_number(text): if len(text) < 2: return False if text[0] != ' ': return False text = text[1:] if '+' in text and '-' in text: return False if '+' in text: if text.count('+') != 1: return False if text[0] != '+': return False text = text[1:] if not text: return False if '-' in text: if text.count('-') != 1: return False if text[0] != '-': return False text = text[1:] if not text: return False valid_set = frozenset(string.digits) value_set = frozenset(text) if len(value_set - valid_set) != 0: return False return True ################################################################################ ################################################################################ from Interpreter import partition_number VMC_2_TRI = { (INS.PUSH, True): (0, 0), (INS.COPY, False): (0, 2, 0), (INS.COPY, True): (0, 1, 0), (INS.SWAP, False): (0, 2, 1), (INS.AWAY, False): (0, 2, 2), (INS.AWAY, True): (0, 1, 2), (INS.ADD, False): (1, 0, 0, 0), (INS.SUB, False): (1, 0, 0, 1), (INS.MUL, False): (1, 0, 0, 2), (INS.DIV, False): (1, 0, 1, 0), (INS.MOD, False): (1, 0, 1, 1), (INS.SET, False): (1, 1, 0), (INS.GET, False): (1, 1, 1), (INS.PART, True): (2, 0, 0), (INS.CALL, True): (2, 0, 1), (INS.GOTO, True): (2, 0, 2), (INS.ZERO, True): (2, 1, 0), (INS.LESS, True): (2, 1, 1), (INS.BACK, False): (2, 1, 2), (INS.EXIT, False): (2, 2, 2), (INS.OCHR, False): (1, 2, 0, 0), (INS.OINT, False): (1, 2, 0, 1), (INS.ICHR, False): (1, 2, 1, 0), (INS.IINT, False): (1, 2, 1, 1) } ################################################################################ def to_trinary(program): trinary_code = [] for ins in program: if isinstance(ins, tuple): ins, arg = ins trinary_code.extend(VMC_2_TRI[(ins, True)]) trinary_code.extend(from_number(arg)) else: trinary_code.extend(VMC_2_TRI[(ins, False)]) return tuple(trinary_code) def from_number(arg): code = [int(arg < 0)] if arg: for bit in reversed(list(partition_number(abs(arg), 2))): code.append(bit) return code + [2] return code + [0, 2] to_ws = lambda trinary: ''.join(' \t\n'[index] for index in trinary) def compile_wsa(source): program = parse(source) trinary = to_trinary(program) ws_code = to_ws(trinary) return ws_code ################################################################################ ################################################################################ import os import sys import time import traceback def main(): name, source, command_line, error = get_source() if not error: start = time.clock() try: ws_code = compile_wsa(source) except: print('ERROR: File could not be compiled.\n') traceback.print_exc() error = True else: path = os.path.join('Programs', name + '.ws') try: open(path, 'w').write(ws_code) except IOError as err: print(err) error = True else: div, mod = divmod((time.clock() - start) * 1000, 1) args = int(div), '{:.3}'.format(mod)[1:] print('DONE: Comipled in {}{} ms'.format(*args)) handle_close(error, command_line) def get_source(): if len(sys.argv) > 1: command_line = True name = sys.argv[1] else: command_line = False try: name = input('Source File: ') except: return None, None, False, True print() path = os.path.join('Assembly', name + '.wsa') try: return name, open(path).read(), command_line, False except IOError as err: print(err) return None, None, command_line, True def handle_close(error, command_line): if error: usage = 'Usage: {} <assembly>'.format(os.path.basename(sys.argv[0])) print('\n{}\n{}'.format('-' * len(usage), usage)) if not command_line: time.sleep(10) ################################################################################ if __name__ == '__main__': main() Whitespace Helpers #! /usr/bin/env python """Helpers.py Includes a function to encode Python strings into my WSA format. Has a "PRINT_LINE" function that can be copied to a WSA program. Contains a "PRINT" function and documentation as an explanation.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 1 $' ################################################################################ def encode_string(string, addr): print(' push', addr) print(' push', len(string)) print(' set') addr += 1 for offset, character in enumerate(string): print(' push', addr + offset) print(' push', ord(character)) print(' set') ################################################################################ # Prints a string with newline. # push addr # call "PRINT_LINE" """ part "PRINT_LINE" call "PRINT" push 10 ochr back """ ################################################################################ # def print(array): # if len(array) <= 0: # return # offset = 1 # while len(array) - offset >= 0: # ptr = array.ptr + offset # putch(array[ptr]) # offset += 1 """ part "PRINT" # Line 1-2 copy get less "__PRINT_RET_1" copy get zero "__PRINT_RET_1" # Line 3 push 1 # Line 4 part "__PRINT_LOOP" copy copy 2 get swap sub less "__PRINT_RET_2" # Line 5 copy 1 copy 1 add # Line 6 get ochr # Line 7 push 1 add goto "__PRINT_LOOP" part "__PRINT_RET_2" away part "__PRINT_RET_1" away back """ Whitespace Interpreter #! /usr/bin/env python """Interpreter.py Runs programs in "Programs" and creates *.WSO files when needed. Can be executed directly by double-click or on the command line. If run on command line, add "ASM" flag to dump program assembly.""" ################################################################################ __author__ = 'Stephen "Zero" Chappell <[email protected]>' __date__ = '14 March 2010' __version__ = '$Revision: 4 $' ################################################################################ def test_file(path): disassemble(parse(trinary(load(path))), True) ################################################################################ load = lambda ws: ''.join(c for r in open(ws) for c in r if c in ' \t\n') trinary = lambda ws: tuple(' \t\n'.index(c) for c in ws) ################################################################################ def enum(names): names = names.replace(',', ' ').split() space = dict((reversed(pair) for pair in enumerate(names)), __slots__=()) return type('enum', (object,), space)() INS = enum('''\ PUSH, COPY, SWAP, AWAY, \ ADD, SUB, MUL, DIV, MOD, \ SET, GET, \ PART, CALL, GOTO, ZERO, LESS, BACK, EXIT, \ OCHR, OINT, ICHR, IINT''') ################################################################################ def parse(code): ins = iter(code).__next__ program = [] while True: try: imp = ins() except StopIteration: return tuple(program) if imp == 0: # [Space] parse_stack(ins, program) elif imp == 1: # [Tab] imp = ins() if imp == 0: # [Tab][Space] parse_math(ins, program) elif imp == 1: # [Tab][Tab] parse_heap(ins, program) else: # [Tab][Line] parse_io(ins, program) else: # [Line] parse_flow(ins, program) def parse_number(ins): sign = ins() if sign == 2: raise StopIteration() buffer = '' code = ins() if code == 2: raise StopIteration() while code != 2: buffer += str(code) code = ins() if sign == 1: return int(buffer, 2) * -1 return int(buffer, 2) ################################################################################ def parse_stack(ins, program): code = ins() if code == 0: # [Space] number = parse_number(ins) program.append((INS.PUSH, number)) elif code == 1: # [Tab] code = ins() number = parse_number(ins) if code == 0: # [Tab][Space] program.append((INS.COPY, number)) elif code == 1: # [Tab][Tab] raise StopIteration() else: # [Tab][Line] program.append((INS.AWAY, number)) else: # [Line] code = ins() if code == 0: # [Line][Space] program.append(INS.COPY) elif code == 1: # [Line][Tab] program.append(INS.SWAP) else: # [Line][Line] program.append(INS.AWAY) def parse_math(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.ADD) elif code == 1: # [Space][Tab] program.append(INS.SUB) else: # [Space][Line] program.append(INS.MUL) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.DIV) elif code == 1: # [Tab][Tab] program.append(INS.MOD) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_heap(ins, program): code = ins() if code == 0: # [Space] program.append(INS.SET) elif code == 1: # [Tab] program.append(INS.GET) else: # [Line] raise StopIteration() def parse_io(ins, program): code = ins() if code == 0: # [Space] code = ins() if code == 0: # [Space][Space] program.append(INS.OCHR) elif code == 1: # [Space][Tab] program.append(INS.OINT) else: # [Space][Line] raise StopIteration() elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] program.append(INS.ICHR) elif code == 1: # [Tab][Tab] program.append(INS.IINT) else: # [Tab][Line] raise StopIteration() else: # [Line] raise StopIteration() def parse_flow(ins, program): code = ins() if code == 0: # [Space] code = ins() label = parse_number(ins) if code == 0: # [Space][Space] program.append((INS.PART, label)) elif code == 1: # [Space][Tab] program.append((INS.CALL, label)) else: # [Space][Line] program.append((INS.GOTO, label)) elif code == 1: # [Tab] code = ins() if code == 0: # [Tab][Space] label = parse_number(ins) program.append((INS.ZERO, label)) elif code == 1: # [Tab][Tab] label = parse_number(ins) program.append((INS.LESS, label)) else: # [Tab][Line] program.append(INS.BACK) else: # [Line] code = ins() if code == 2: # [Line][Line] program.append(INS.EXIT) else: # [Line][Space] or [Line][Tab] raise StopIteration() ################################################################################ MNEMONIC = '\ push copy swap away add sub mul div mod set get part \ call goto zero less back exit ochr oint ichr iint'.split() HAS_ARG = [getattr(INS, name) for name in 'PUSH COPY AWAY PART CALL GOTO ZERO LESS'.split()] HAS_LABEL = [getattr(INS, name) for name in 'PART CALL GOTO ZERO LESS'.split()] def disassemble(program, names=False): if names: names = create_names(program) for ins in program: if isinstance(ins, tuple): ins, arg = ins assert ins in HAS_ARG has_arg = True else: assert INS.PUSH <= ins <= INS.IINT has_arg = False if ins == INS.PART: if names: print(MNEMONIC[ins], '"' + names[arg] + '"') else: print(MNEMONIC[ins], arg) elif has_arg and ins in HAS_ARG: if ins in HAS_LABEL and names: assert arg in names print(' ' + MNEMONIC[ins], '"' + names[arg] + '"') else: print(' ' + MNEMONIC[ins], arg) else: print(' ' + MNEMONIC[ins]) ################################################################################ def create_names(program): names = {} number = 1 for ins in program: if isinstance(ins, tuple) and ins[0] == INS.PART: label = ins[1] assert label not in names names[label] = number_to_name(number) number += 1 return names def number_to_name(number): name = '' for offset in reversed(list(partition_number(number, 27))): if offset: name += chr(ord('A') + offset - 1) else: name += '_' return name def partition_number(number, base): div, mod = divmod(number, base) yield mod while div: div, mod = divmod(div, base) yield mod ################################################################################ CODE = (' \t\n', ' \n ', ' \t \t\n', ' \n\t', ' \n\n', ' \t\n \t\n', '\t ', '\t \t', '\t \n', '\t \t ', '\t \t\t', '\t\t ', '\t\t\t', '\n \t\n', '\n \t \t\n', '\n \n \t\n', '\n\t \t\n', '\n\t\t \t\n', '\n\t\n', '\n\n\n', '\t\n ', '\t\n \t', '\t\n\t ', '\t\n\t\t') EXAMPLE = ''.join(CODE) ################################################################################ NOTES = '''\ STACK ===== push number copy copy number swap away away number MATH ==== add sub mul div mod HEAP ==== set get FLOW ==== part label call label goto label zero label less label back exit I/O === ochr oint ichr iint''' ################################################################################ ################################################################################ class Stack: def __init__(self): self.__data = [] # Stack Operators def push(self, number): self.__data.append(number) def copy(self, number=None): if number is None: self.__data.append(self.__data[-1]) else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size self.__data.append(self.__data[index]) def swap(self): self.__data[-2], self.__data[-1] = self.__data[-1], self.__data[-2] def away(self, number=None): if number is None: self.__data.pop() else: size = len(self.__data) index = size - number - 1 assert 0 <= index < size del self.__data[index:-1] # Math Operators def add(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix + suffix) def sub(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix - suffix) def mul(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix * suffix) def div(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix // suffix) def mod(self): suffix = self.__data.pop() prefix = self.__data.pop() self.__data.append(prefix % suffix) # Program Operator def pop(self): return self.__data.pop() ################################################################################ class Heap: def __init__(self): self.__data = {} def set_(self, addr, item): if item: self.__data[addr] = item elif addr in self.__data: del self.__data[addr] def get_(self, addr): return self.__data.get(addr, 0) ################################################################################ import os import zlib import msvcrt import pickle import string class CleanExit(Exception): pass NOP = lambda arg: None DEBUG_WHITESPACE = False ################################################################################ class Program: NO_ARGS = INS.COPY, INS.SWAP, INS.AWAY, INS.ADD, \ INS.SUB, INS.MUL, INS.DIV, INS.MOD, \ INS.SET, INS.GET, INS.BACK, INS.EXIT, \ INS.OCHR, INS.OINT, INS.ICHR, INS.IINT HAS_ARG = INS.PUSH, INS.COPY, INS.AWAY, INS.PART, \ INS.CALL, INS.GOTO, INS.ZERO, INS.LESS def __init__(self, code): self.__data = code self.__validate() self.__build_jump() self.__check_jump() self.__setup_exec() def __setup_exec(self): self.__iptr = 0 self.__stck = stack = Stack() self.__heap = Heap() self.__cast = [] self.__meth = (stack.push, stack.copy, stack.swap, stack.away, stack.add, stack.sub, stack.mul, stack.div, stack.mod, self.__set, self.__get, NOP, self.__call, self.__goto, self.__zero, self.__less, self.__back, self.__exit, self.__ochr, self.__oint, self.__ichr, self.__iint) def step(self): ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def run(self): while True: ins = self.__data[self.__iptr] self.__iptr += 1 if isinstance(ins, tuple): self.__meth[ins[0]](ins[1]) else: self.__meth[ins]() def __oint(self): for digit in str(self.__stck.pop()): msvcrt.putwch(digit) def __ichr(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() while True: char = msvcrt.getwch() if char in '\x00\xE0': msvcrt.getwch() elif char in string.printable: char = char.replace('\r', '\n') msvcrt.putwch(char) break item = ord(char) # Storing Number self.__heap.set_(addr, item) def __iint(self): addr = self.__stck.pop() # Input Routine while msvcrt.kbhit(): msvcrt.getwch() buff = '' char = msvcrt.getwch() while char != '\r' or not buff: if char in '\x00\xE0': msvcrt.getwch() elif char in '+-' and not buff: msvcrt.putwch(char) buff += char elif '0' <= char <= '9': msvcrt.putwch(char) buff += char elif char == '\b': if buff: buff = buff[:-1] msvcrt.putwch(char) msvcrt.putwch(' ') msvcrt.putwch(char) char = msvcrt.getwch() msvcrt.putwch(char) msvcrt.putwch('\n') item = int(buff) # Storing Number self.__heap.set_(addr, item) def __goto(self, label): self.__iptr = self.__jump[label] def __zero(self, label): if self.__stck.pop() == 0: self.__iptr = self.__jump[label] def __less(self, label): if self.__stck.pop() < 0: self.__iptr = self.__jump[label] def __exit(self): self.__setup_exec() raise CleanExit() def __set(self): item = self.__stck.pop() addr = self.__stck.po

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  • java: List wrapper where get()/set() is allowed but add/remove is not

    - by Jason S
    I need to wrap a List<T> with some class that allows calls to set/get but does not allow add/remove calls, so that the list remains "stuck" at a fixed length. I think I have a thin wrapper class (below) that will work, but I'm not 100% positive. Did I miss anything obvious? import java.util.Collection; import java.util.Iterator; import java.util.List; import java.util.ListIterator; class RestrictedListWrapper<T> implements List<T> { static <T> T fail() throws UnsupportedOperationException { throw new UnsupportedOperationException(); } static private class IteratorWrapper<T> implements ListIterator<T> { final private ListIterator<T> iter; private IteratorWrapper(ListIterator<T> iter) { this.iter = iter; } static public <T> RestrictedListWrapper.IteratorWrapper<T> wrap(ListIterator<T> target) { return new RestrictedListWrapper.IteratorWrapper<T>(target); } @Override public void add(T e) { fail(); } @Override public boolean hasNext() { return this.iter.hasNext(); } @Override public boolean hasPrevious() { return this.iter.hasPrevious(); } @Override public T next() { return this.iter.next(); } @Override public int nextIndex() { return this.iter.nextIndex(); } @Override public T previous() { return this.iter.previous(); } @Override public int previousIndex() { return this.iter.previousIndex(); } @Override public void remove() { fail(); } @Override public void set(T e) { this.iter.set(e); } } final private List<T> list; private RestrictedListWrapper(List<T> list) { this.list = list; } static public <T> RestrictedListWrapper<T> wrap(List<T> target) { return new RestrictedListWrapper<T>(target); } @Override public boolean add(T arg0) { return fail(); } @Override public void add(int index, T element) { fail(); } @Override public boolean addAll(Collection<? extends T> arg0) { return fail(); } @Override public boolean addAll(int arg0, Collection<? extends T> arg1) { return fail(); } /** * clear() allows setting all members of the list to null */ @Override public void clear() { ListIterator<T> it = this.list.listIterator(); while (it.hasNext()) { it.set(null); it.next(); } } @Override public boolean contains(Object o) { return this.list.contains(o); } @Override public boolean containsAll(Collection<?> c) { return this.list.containsAll(c); } @Override public T get(int index) { return this.list.get(index); } @Override public int indexOf(Object o) { return this.list.indexOf(o); } @Override public boolean isEmpty() { return false; } @Override public Iterator<T> iterator() { return listIterator(); } @Override public int lastIndexOf(Object o) { return this.list.lastIndexOf(o); } @Override public ListIterator<T> listIterator() { return IteratorWrapper.wrap(this.list.listIterator()); } @Override public ListIterator<T> listIterator(int index) { return IteratorWrapper.wrap(this.list.listIterator(index)); } @Override public boolean remove(Object o) { return fail(); } @Override public T remove(int index) { fail(); return fail(); } @Override public boolean removeAll(Collection<?> c) { return fail(); } @Override public boolean retainAll(Collection<?> c) { return fail(); } @Override public T set(int index, T element) { return this.list.set(index, element); } @Override public int size() { return this.list.size(); } @Override public List<T> subList(int fromIndex, int toIndex) { return new RestrictedListWrapper<T>(this.list.subList(fromIndex, toIndex)); } @Override public Object[] toArray() { return this.list.toArray(); } @Override public <T> T[] toArray(T[] a) { return this.list.toArray(a); } }

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  • Can this PHP version of SPICE be improved?

    - by Noctis Skytower
    I do not know much about PHP's standard library of functions and was wondering if the following code can be improved in any way. The implementation should yield the same results, the API should remain as it is, but ways to make is more PHP-ish would be greatly appreciated. This is a custom encryption library. Code <?php /*************************************** Create random major and minor SPICE key. ***************************************/ function crypt_major() { $all = range("\x00", "\xFF"); shuffle($all); $major_key = implode("", $all); return $major_key; } function crypt_minor() { $sample = array(); do { array_push($sample, 0, 1, 2, 3); } while (count($sample) != 256); shuffle($sample); $list = array(); for ($index = 0; $index < 64; $index++) { $b12 = $sample[$index * 4] << 6; $b34 = $sample[$index * 4 + 1] << 4; $b56 = $sample[$index * 4 + 2] << 2; $b78 = $sample[$index * 4 + 3]; array_push($list, $b12 + $b34 + $b56 + $b78); } $minor_key = implode("", array_map("chr", $list)); return $minor_key; } /*************************************** Create the SPICE key via the given name. ***************************************/ function named_major($name) { srand(crc32($name)); return crypt_major(); } function named_minor($name) { srand(crc32($name)); return crypt_minor(); } /*************************************** Check validity for major and minor keys. ***************************************/ function _check_major($key) { if (is_string($key) && strlen($key) == 256) { foreach (range("\x00", "\xFF") as $char) { if (substr_count($key, $char) == 0) { return FALSE; } } return TRUE; } return FALSE; } function _check_minor($key) { if (is_string($key) && strlen($key) == 64) { $indexs = array(); foreach (array_map("ord", str_split($key)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($indexs, ($byte >> $shift) & 3); } } $dict = array_count_values($indexs); foreach (range(0, 3) as $index) { if ($dict[$index] != 64) { return FALSE; } } return TRUE; } return FALSE; } /*************************************** Create encode maps for encode functions. ***************************************/ function _encode_map_1($major) { return array_map("ord", str_split($major)); } function _encode_map_2($minor) { $map_2 = array(array(), array(), array(), array()); $list = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($list, ($byte >> $shift) & 3); } } for ($byte = 0; $byte < 256; $byte++) { array_push($map_2[$list[$byte]], chr($byte)); } return $map_2; } /*************************************** Create decode maps for decode functions. ***************************************/ function _decode_map_1($minor) { $map_1 = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($map_1, ($byte >> $shift) & 3); } } return $map_1; }function _decode_map_2($major) { $map_2 = array(); $temp = array_map("ord", str_split($major)); for ($byte = 0; $byte < 256; $byte++) { $map_2[$temp[$byte]] = chr($byte); } return $map_2; } /*************************************** Encrypt or decrypt the string with maps. ***************************************/ function _encode($string, $map_1, $map_2) { $cache = ""; foreach (str_split($string) as $char) { $byte = $map_1[ord($char)]; foreach (range(6, 0, 2) as $shift) { $cache .= $map_2[($byte >> $shift) & 3][mt_rand(0, 63)]; } } return $cache; } function _decode($string, $map_1, $map_2) { $cache = ""; $temp = str_split($string); for ($iter = 0; $iter < strlen($string) / 4; $iter++) { $b12 = $map_1[ord($temp[$iter * 4])] << 6; $b34 = $map_1[ord($temp[$iter * 4 + 1])] << 4; $b56 = $map_1[ord($temp[$iter * 4 + 2])] << 2; $b78 = $map_1[ord($temp[$iter * 4 + 3])]; $cache .= $map_2[$b12 + $b34 + $b56 + $b78]; } return $cache; } /*************************************** This is the public interface for coding. ***************************************/ function encode_string($string, $major, $minor) { if (is_string($string)) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _encode_map_1($major); $map_2 = _encode_map_2($minor); return _encode($string, $map_1, $map_2); } } return FALSE; } function decode_string($string, $major, $minor) { if (is_string($string) && strlen($string) % 4 == 0) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _decode_map_1($minor); $map_2 = _decode_map_2($major); return _decode($string, $map_1, $map_2); } } return FALSE; } ?> This is a sample showing how the code is being used. Hex editors may be of help with the input / output. Example <?php # get and process all of the form data @ $input = htmlspecialchars($_POST["input"]); @ $majorname = htmlspecialchars($_POST["majorname"]); @ $minorname = htmlspecialchars($_POST["minorname"]); @ $majorkey = htmlspecialchars($_POST["majorkey"]); @ $minorkey = htmlspecialchars($_POST["minorkey"]); @ $output = htmlspecialchars($_POST["output"]); # process the submissions by operation # CREATE @ $operation = $_POST["operation"]; if ($operation == "Create") { if (strlen($_POST["majorname"]) == 0) { $majorkey = bin2hex(crypt_major()); } if (strlen($_POST["minorname"]) == 0) { $minorkey = bin2hex(crypt_minor()); } if (strlen($_POST["majorname"]) != 0) { $majorkey = bin2hex(named_major($_POST["majorname"])); } if (strlen($_POST["minorname"]) != 0) { $minorkey = bin2hex(named_minor($_POST["minorname"])); } } # ENCRYPT or DECRYPT function is_hex($char) { if ($char == "0"): return TRUE; elseif ($char == "1"): return TRUE; elseif ($char == "2"): return TRUE; elseif ($char == "3"): return TRUE; elseif ($char == "4"): return TRUE; elseif ($char == "5"): return TRUE; elseif ($char == "6"): return TRUE; elseif ($char == "7"): return TRUE; elseif ($char == "8"): return TRUE; elseif ($char == "9"): return TRUE; elseif ($char == "a"): return TRUE; elseif ($char == "b"): return TRUE; elseif ($char == "c"): return TRUE; elseif ($char == "d"): return TRUE; elseif ($char == "e"): return TRUE; elseif ($char == "f"): return TRUE; else: return FALSE; endif; } function hex2bin($str) { if (strlen($str) % 2 == 0): $string = strtolower($str); else: $string = strtolower("0" . $str); endif; $cache = ""; $temp = str_split($str); for ($index = 0; $index < count($temp) / 2; $index++) { $h1 = $temp[$index * 2]; if (is_hex($h1)) { $h2 = $temp[$index * 2 + 1]; if (is_hex($h2)) { $cache .= chr(hexdec($h1 . $h2)); } else { return FALSE; } } else { return FALSE; } } return $cache; } if ($operation == "Encrypt" || $operation == "Decrypt") { # CHECK FOR ANY ERROR $errors = array(); if (strlen($_POST["input"]) == 0) { $output = ""; } $binmajor = hex2bin($_POST["majorkey"]); if (strlen($_POST["majorkey"]) == 0) { array_push($errors, "There must be a major key."); } elseif ($binmajor == FALSE) { array_push($errors, "The major key must be in hex."); } elseif (_check_major($binmajor) == FALSE) { array_push($errors, "The major key is corrupt."); } $binminor = hex2bin($_POST["minorkey"]); if (strlen($_POST["minorkey"]) == 0) { array_push($errors, "There must be a minor key."); } elseif ($binminor == FALSE) { array_push($errors, "The minor key must be in hex."); } elseif (_check_minor($binminor) == FALSE) { array_push($errors, "The minor key is corrupt."); } if ($_POST["operation"] == "Decrypt") { $bininput = hex2bin(str_replace("\r", "", str_replace("\n", "", $_POST["input"]))); if ($bininput == FALSE) { if (strlen($_POST["input"]) != 0) { array_push($errors, "The input data must be in hex."); } } elseif (strlen($bininput) % 4 != 0) { array_push($errors, "The input data is corrupt."); } } if (count($errors) != 0) { # ERRORS ARE FOUND $output = "ERROR:"; foreach ($errors as $error) { $output .= "\n" . $error; } } elseif (strlen($_POST["input"]) != 0) { # CONTINUE WORKING if ($_POST["operation"] == "Encrypt") { # ENCRYPT $output = substr(chunk_split(bin2hex(encode_string($_POST["input"], $binmajor, $binminor)), 58), 0, -2); } else { # DECRYPT $output = htmlspecialchars(decode_string($bininput, $binmajor, $binminor)); } } } # echo the form with the values filled echo "<P><TEXTAREA class=maintextarea name=input rows=25 cols=25>" . $input . "</TEXTAREA></P>\n"; echo "<P>Major Name:</P>\n"; echo "<P><INPUT id=textbox1 name=majorname value=\"" . $majorname . "\"></P>\n"; echo "<P>Minor Name:</P>\n"; echo "<P><INPUT id=textbox1 name=minorname value=\"" . $minorname . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Create name=operation>\n"; echo "</DIV>\n"; echo "<P>Major Key:</P>\n"; echo "<P><INPUT id=textbox1 name=majorkey value=\"" . $majorkey . "\"></P>\n"; echo "<P>Minor Key:</P>\n"; echo "<P><INPUT id=textbox1 name=minorkey value=\"" . $minorkey . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Encrypt name=operation> \n"; echo "<INPUT class=submit type=submit value=Decrypt name=operation> </DIV>\n"; echo "<P>Result:</P>\n"; echo "<P><TEXTAREA class=maintextarea name=output rows=25 readOnly cols=25>" . $output . "</TEXTAREA></P></DIV></FORM>\n"; ?>

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  • How can this PHP code be improved? What should be changed?

    - by Noctis Skytower
    This is a custom encryption library. I do not know much about PHP's standard library of functions and was wondering if the following code can be improved in any way. The implementation should yield the same results, the API should remain as it is, but ways to make is more PHP-ish would be greatly appreciated. Code <?php /*************************************** Create random major and minor SPICE key. ***************************************/ function crypt_major() { $all = range("\x00", "\xFF"); shuffle($all); $major_key = implode("", $all); return $major_key; } function crypt_minor() { $sample = array(); do { array_push($sample, 0, 1, 2, 3); } while (count($sample) != 256); shuffle($sample); $list = array(); for ($index = 0; $index < 64; $index++) { $b12 = $sample[$index * 4] << 6; $b34 = $sample[$index * 4 + 1] << 4; $b56 = $sample[$index * 4 + 2] << 2; $b78 = $sample[$index * 4 + 3]; array_push($list, $b12 + $b34 + $b56 + $b78); } $minor_key = implode("", array_map("chr", $list)); return $minor_key; } /*************************************** Create the SPICE key via the given name. ***************************************/ function named_major($name) { srand(crc32($name)); return crypt_major(); } function named_minor($name) { srand(crc32($name)); return crypt_minor(); } /*************************************** Check validity for major and minor keys. ***************************************/ function _check_major($key) { if (is_string($key) && strlen($key) == 256) { foreach (range("\x00", "\xFF") as $char) { if (substr_count($key, $char) == 0) { return FALSE; } } return TRUE; } return FALSE; } function _check_minor($key) { if (is_string($key) && strlen($key) == 64) { $indexs = array(); foreach (array_map("ord", str_split($key)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($indexs, ($byte >> $shift) & 3); } } $dict = array_count_values($indexs); foreach (range(0, 3) as $index) { if ($dict[$index] != 64) { return FALSE; } } return TRUE; } return FALSE; } /*************************************** Create encode maps for encode functions. ***************************************/ function _encode_map_1($major) { return array_map("ord", str_split($major)); } function _encode_map_2($minor) { $map_2 = array(array(), array(), array(), array()); $list = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($list, ($byte >> $shift) & 3); } } for ($byte = 0; $byte < 256; $byte++) { array_push($map_2[$list[$byte]], chr($byte)); } return $map_2; } /*************************************** Create decode maps for decode functions. ***************************************/ function _decode_map_1($minor) { $map_1 = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($map_1, ($byte >> $shift) & 3); } } return $map_1; }function _decode_map_2($major) { $map_2 = array(); $temp = array_map("ord", str_split($major)); for ($byte = 0; $byte < 256; $byte++) { $map_2[$temp[$byte]] = chr($byte); } return $map_2; } /*************************************** Encrypt or decrypt the string with maps. ***************************************/ function _encode($string, $map_1, $map_2) { $cache = ""; foreach (str_split($string) as $char) { $byte = $map_1[ord($char)]; foreach (range(6, 0, 2) as $shift) { $cache .= $map_2[($byte >> $shift) & 3][mt_rand(0, 63)]; } } return $cache; } function _decode($string, $map_1, $map_2) { $cache = ""; $temp = str_split($string); for ($iter = 0; $iter < strlen($string) / 4; $iter++) { $b12 = $map_1[ord($temp[$iter * 4])] << 6; $b34 = $map_1[ord($temp[$iter * 4 + 1])] << 4; $b56 = $map_1[ord($temp[$iter * 4 + 2])] << 2; $b78 = $map_1[ord($temp[$iter * 4 + 3])]; $cache .= $map_2[$b12 + $b34 + $b56 + $b78]; } return $cache; } /*************************************** This is the public interface for coding. ***************************************/ function encode_string($string, $major, $minor) { if (is_string($string)) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _encode_map_1($major); $map_2 = _encode_map_2($minor); return _encode($string, $map_1, $map_2); } } return FALSE; } function decode_string($string, $major, $minor) { if (is_string($string) && strlen($string) % 4 == 0) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _decode_map_1($minor); $map_2 = _decode_map_2($major); return _decode($string, $map_1, $map_2); } } return FALSE; } ?> This is a sample showing how the code is being used. Hex editors may be of help with the input / output. Example <?php # get and process all of the form data @ $input = htmlspecialchars($_POST["input"]); @ $majorname = htmlspecialchars($_POST["majorname"]); @ $minorname = htmlspecialchars($_POST["minorname"]); @ $majorkey = htmlspecialchars($_POST["majorkey"]); @ $minorkey = htmlspecialchars($_POST["minorkey"]); @ $output = htmlspecialchars($_POST["output"]); # process the submissions by operation # CREATE @ $operation = $_POST["operation"]; if ($operation == "Create") { if (strlen($_POST["majorname"]) == 0) { $majorkey = bin2hex(crypt_major()); } if (strlen($_POST["minorname"]) == 0) { $minorkey = bin2hex(crypt_minor()); } if (strlen($_POST["majorname"]) != 0) { $majorkey = bin2hex(named_major($_POST["majorname"])); } if (strlen($_POST["minorname"]) != 0) { $minorkey = bin2hex(named_minor($_POST["minorname"])); } } # ENCRYPT or DECRYPT function is_hex($char) { if ($char == "0"): return TRUE; elseif ($char == "1"): return TRUE; elseif ($char == "2"): return TRUE; elseif ($char == "3"): return TRUE; elseif ($char == "4"): return TRUE; elseif ($char == "5"): return TRUE; elseif ($char == "6"): return TRUE; elseif ($char == "7"): return TRUE; elseif ($char == "8"): return TRUE; elseif ($char == "9"): return TRUE; elseif ($char == "a"): return TRUE; elseif ($char == "b"): return TRUE; elseif ($char == "c"): return TRUE; elseif ($char == "d"): return TRUE; elseif ($char == "e"): return TRUE; elseif ($char == "f"): return TRUE; else: return FALSE; endif; } function hex2bin($str) { if (strlen($str) % 2 == 0): $string = strtolower($str); else: $string = strtolower("0" . $str); endif; $cache = ""; $temp = str_split($str); for ($index = 0; $index < count($temp) / 2; $index++) { $h1 = $temp[$index * 2]; if (is_hex($h1)) { $h2 = $temp[$index * 2 + 1]; if (is_hex($h2)) { $cache .= chr(hexdec($h1 . $h2)); } else { return FALSE; } } else { return FALSE; } } return $cache; } if ($operation == "Encrypt" || $operation == "Decrypt") { # CHECK FOR ANY ERROR $errors = array(); if (strlen($_POST["input"]) == 0) { $output = ""; } $binmajor = hex2bin($_POST["majorkey"]); if (strlen($_POST["majorkey"]) == 0) { array_push($errors, "There must be a major key."); } elseif ($binmajor == FALSE) { array_push($errors, "The major key must be in hex."); } elseif (_check_major($binmajor) == FALSE) { array_push($errors, "The major key is corrupt."); } $binminor = hex2bin($_POST["minorkey"]); if (strlen($_POST["minorkey"]) == 0) { array_push($errors, "There must be a minor key."); } elseif ($binminor == FALSE) { array_push($errors, "The minor key must be in hex."); } elseif (_check_minor($binminor) == FALSE) { array_push($errors, "The minor key is corrupt."); } if ($_POST["operation"] == "Decrypt") { $bininput = hex2bin(str_replace("\r", "", str_replace("\n", "", $_POST["input"]))); if ($bininput == FALSE) { if (strlen($_POST["input"]) != 0) { array_push($errors, "The input data must be in hex."); } } elseif (strlen($bininput) % 4 != 0) { array_push($errors, "The input data is corrupt."); } } if (count($errors) != 0) { # ERRORS ARE FOUND $output = "ERROR:"; foreach ($errors as $error) { $output .= "\n" . $error; } } elseif (strlen($_POST["input"]) != 0) { # CONTINUE WORKING if ($_POST["operation"] == "Encrypt") { # ENCRYPT $output = substr(chunk_split(bin2hex(encode_string($_POST["input"], $binmajor, $binminor)), 58), 0, -2); } else { # DECRYPT $output = htmlspecialchars(decode_string($bininput, $binmajor, $binminor)); } } } # echo the form with the values filled echo "<P><TEXTAREA class=maintextarea name=input rows=25 cols=25>" . $input . "</TEXTAREA></P>\n"; echo "<P>Major Name:</P>\n"; echo "<P><INPUT id=textbox1 name=majorname value=\"" . $majorname . "\"></P>\n"; echo "<P>Minor Name:</P>\n"; echo "<P><INPUT id=textbox1 name=minorname value=\"" . $minorname . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Create name=operation>\n"; echo "</DIV>\n"; echo "<P>Major Key:</P>\n"; echo "<P><INPUT id=textbox1 name=majorkey value=\"" . $majorkey . "\"></P>\n"; echo "<P>Minor Key:</P>\n"; echo "<P><INPUT id=textbox1 name=minorkey value=\"" . $minorkey . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Encrypt name=operation> \n"; echo "<INPUT class=submit type=submit value=Decrypt name=operation> </DIV>\n"; echo "<P>Result:</P>\n"; echo "<P><TEXTAREA class=maintextarea name=output rows=25 readOnly cols=25>" . $output . "</TEXTAREA></P></DIV></FORM>\n"; ?> What should be editted for better memory efficiency or faster execution?

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  • How can this PHP code be improved? What should change?

    - by Noctis Skytower
    This is a custom encryption library. I do not know much about PHP's standard library of functions and was wondering if the following code can be improved in any way. The implementation should yield the same results, the API should remain as it is, but ways to make is more PHP-ish would be greatly appreciated. Code <?php /*************************************** Create random major and minor SPICE key. ***************************************/ function crypt_major() { $all = range("\x00", "\xFF"); shuffle($all); $major_key = implode("", $all); return $major_key; } function crypt_minor() { $sample = array(); do { array_push($sample, 0, 1, 2, 3); } while (count($sample) != 256); shuffle($sample); $list = array(); for ($index = 0; $index < 64; $index++) { $b12 = $sample[$index * 4] << 6; $b34 = $sample[$index * 4 + 1] << 4; $b56 = $sample[$index * 4 + 2] << 2; $b78 = $sample[$index * 4 + 3]; array_push($list, $b12 + $b34 + $b56 + $b78); } $minor_key = implode("", array_map("chr", $list)); return $minor_key; } /*************************************** Create the SPICE key via the given name. ***************************************/ function named_major($name) { srand(crc32($name)); return crypt_major(); } function named_minor($name) { srand(crc32($name)); return crypt_minor(); } /*************************************** Check validity for major and minor keys. ***************************************/ function _check_major($key) { if (is_string($key) && strlen($key) == 256) { foreach (range("\x00", "\xFF") as $char) { if (substr_count($key, $char) == 0) { return FALSE; } } return TRUE; } return FALSE; } function _check_minor($key) { if (is_string($key) && strlen($key) == 64) { $indexs = array(); foreach (array_map("ord", str_split($key)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($indexs, ($byte >> $shift) & 3); } } $dict = array_count_values($indexs); foreach (range(0, 3) as $index) { if ($dict[$index] != 64) { return FALSE; } } return TRUE; } return FALSE; } /*************************************** Create encode maps for encode functions. ***************************************/ function _encode_map_1($major) { return array_map("ord", str_split($major)); } function _encode_map_2($minor) { $map_2 = array(array(), array(), array(), array()); $list = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($list, ($byte >> $shift) & 3); } } for ($byte = 0; $byte < 256; $byte++) { array_push($map_2[$list[$byte]], chr($byte)); } return $map_2; } /*************************************** Create decode maps for decode functions. ***************************************/ function _decode_map_1($minor) { $map_1 = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($map_1, ($byte >> $shift) & 3); } } return $map_1; }function _decode_map_2($major) { $map_2 = array(); $temp = array_map("ord", str_split($major)); for ($byte = 0; $byte < 256; $byte++) { $map_2[$temp[$byte]] = chr($byte); } return $map_2; } /*************************************** Encrypt or decrypt the string with maps. ***************************************/ function _encode($string, $map_1, $map_2) { $cache = ""; foreach (str_split($string) as $char) { $byte = $map_1[ord($char)]; foreach (range(6, 0, 2) as $shift) { $cache .= $map_2[($byte >> $shift) & 3][mt_rand(0, 63)]; } } return $cache; } function _decode($string, $map_1, $map_2) { $cache = ""; $temp = str_split($string); for ($iter = 0; $iter < strlen($string) / 4; $iter++) { $b12 = $map_1[ord($temp[$iter * 4])] << 6; $b34 = $map_1[ord($temp[$iter * 4 + 1])] << 4; $b56 = $map_1[ord($temp[$iter * 4 + 2])] << 2; $b78 = $map_1[ord($temp[$iter * 4 + 3])]; $cache .= $map_2[$b12 + $b34 + $b56 + $b78]; } return $cache; } /*************************************** This is the public interface for coding. ***************************************/ function encode_string($string, $major, $minor) { if (is_string($string)) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _encode_map_1($major); $map_2 = _encode_map_2($minor); return _encode($string, $map_1, $map_2); } } return FALSE; } function decode_string($string, $major, $minor) { if (is_string($string) && strlen($string) % 4 == 0) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _decode_map_1($minor); $map_2 = _decode_map_2($major); return _decode($string, $map_1, $map_2); } } return FALSE; } ?> This is a sample showing how the code is being used. Hex editors may be of help with the input / output. Example <?php # get and process all of the form data @ $input = htmlspecialchars($_POST["input"]); @ $majorname = htmlspecialchars($_POST["majorname"]); @ $minorname = htmlspecialchars($_POST["minorname"]); @ $majorkey = htmlspecialchars($_POST["majorkey"]); @ $minorkey = htmlspecialchars($_POST["minorkey"]); @ $output = htmlspecialchars($_POST["output"]); # process the submissions by operation # CREATE @ $operation = $_POST["operation"]; if ($operation == "Create") { if (strlen($_POST["majorname"]) == 0) { $majorkey = bin2hex(crypt_major()); } if (strlen($_POST["minorname"]) == 0) { $minorkey = bin2hex(crypt_minor()); } if (strlen($_POST["majorname"]) != 0) { $majorkey = bin2hex(named_major($_POST["majorname"])); } if (strlen($_POST["minorname"]) != 0) { $minorkey = bin2hex(named_minor($_POST["minorname"])); } } # ENCRYPT or DECRYPT function is_hex($char) { if ($char == "0"): return TRUE; elseif ($char == "1"): return TRUE; elseif ($char == "2"): return TRUE; elseif ($char == "3"): return TRUE; elseif ($char == "4"): return TRUE; elseif ($char == "5"): return TRUE; elseif ($char == "6"): return TRUE; elseif ($char == "7"): return TRUE; elseif ($char == "8"): return TRUE; elseif ($char == "9"): return TRUE; elseif ($char == "a"): return TRUE; elseif ($char == "b"): return TRUE; elseif ($char == "c"): return TRUE; elseif ($char == "d"): return TRUE; elseif ($char == "e"): return TRUE; elseif ($char == "f"): return TRUE; else: return FALSE; endif; } function hex2bin($str) { if (strlen($str) % 2 == 0): $string = strtolower($str); else: $string = strtolower("0" . $str); endif; $cache = ""; $temp = str_split($str); for ($index = 0; $index < count($temp) / 2; $index++) { $h1 = $temp[$index * 2]; if (is_hex($h1)) { $h2 = $temp[$index * 2 + 1]; if (is_hex($h2)) { $cache .= chr(hexdec($h1 . $h2)); } else { return FALSE; } } else { return FALSE; } } return $cache; } if ($operation == "Encrypt" || $operation == "Decrypt") { # CHECK FOR ANY ERROR $errors = array(); if (strlen($_POST["input"]) == 0) { $output = ""; } $binmajor = hex2bin($_POST["majorkey"]); if (strlen($_POST["majorkey"]) == 0) { array_push($errors, "There must be a major key."); } elseif ($binmajor == FALSE) { array_push($errors, "The major key must be in hex."); } elseif (_check_major($binmajor) == FALSE) { array_push($errors, "The major key is corrupt."); } $binminor = hex2bin($_POST["minorkey"]); if (strlen($_POST["minorkey"]) == 0) { array_push($errors, "There must be a minor key."); } elseif ($binminor == FALSE) { array_push($errors, "The minor key must be in hex."); } elseif (_check_minor($binminor) == FALSE) { array_push($errors, "The minor key is corrupt."); } if ($_POST["operation"] == "Decrypt") { $bininput = hex2bin(str_replace("\r", "", str_replace("\n", "", $_POST["input"]))); if ($bininput == FALSE) { if (strlen($_POST["input"]) != 0) { array_push($errors, "The input data must be in hex."); } } elseif (strlen($bininput) % 4 != 0) { array_push($errors, "The input data is corrupt."); } } if (count($errors) != 0) { # ERRORS ARE FOUND $output = "ERROR:"; foreach ($errors as $error) { $output .= "\n" . $error; } } elseif (strlen($_POST["input"]) != 0) { # CONTINUE WORKING if ($_POST["operation"] == "Encrypt") { # ENCRYPT $output = substr(chunk_split(bin2hex(encode_string($_POST["input"], $binmajor, $binminor)), 58), 0, -2); } else { # DECRYPT $output = htmlspecialchars(decode_string($bininput, $binmajor, $binminor)); } } } # echo the form with the values filled echo "<P><TEXTAREA class=maintextarea name=input rows=25 cols=25>" . $input . "</TEXTAREA></P>\n"; echo "<P>Major Name:</P>\n"; echo "<P><INPUT id=textbox1 name=majorname value=\"" . $majorname . "\"></P>\n"; echo "<P>Minor Name:</P>\n"; echo "<P><INPUT id=textbox1 name=minorname value=\"" . $minorname . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Create name=operation>\n"; echo "</DIV>\n"; echo "<P>Major Key:</P>\n"; echo "<P><INPUT id=textbox1 name=majorkey value=\"" . $majorkey . "\"></P>\n"; echo "<P>Minor Key:</P>\n"; echo "<P><INPUT id=textbox1 name=minorkey value=\"" . $minorkey . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Encrypt name=operation> \n"; echo "<INPUT class=submit type=submit value=Decrypt name=operation> </DIV>\n"; echo "<P>Result:</P>\n"; echo "<P><TEXTAREA class=maintextarea name=output rows=25 readOnly cols=25>" . $output . "</TEXTAREA></P></DIV></FORM>\n"; ?> What should be editted for better memory efficiency or faster execution?

    Read the article

  • What can be improved in this PHP code?

    - by Noctis Skytower
    This is a custom encryption library. I do not know much about PHP's standard library of functions and was wondering if the following code can be improved in any way. The implementation should yield the same results, the API should remain as it is, but ways to make is more PHP-ish would be greatly appreciated. Code <?php /*************************************** Create random major and minor SPICE key. ***************************************/ function crypt_major() { $all = range("\x00", "\xFF"); shuffle($all); $major_key = implode("", $all); return $major_key; } function crypt_minor() { $sample = array(); do { array_push($sample, 0, 1, 2, 3); } while (count($sample) != 256); shuffle($sample); $list = array(); for ($index = 0; $index < 64; $index++) { $b12 = $sample[$index * 4] << 6; $b34 = $sample[$index * 4 + 1] << 4; $b56 = $sample[$index * 4 + 2] << 2; $b78 = $sample[$index * 4 + 3]; array_push($list, $b12 + $b34 + $b56 + $b78); } $minor_key = implode("", array_map("chr", $list)); return $minor_key; } /*************************************** Create the SPICE key via the given name. ***************************************/ function named_major($name) { srand(crc32($name)); return crypt_major(); } function named_minor($name) { srand(crc32($name)); return crypt_minor(); } /*************************************** Check validity for major and minor keys. ***************************************/ function _check_major($key) { if (is_string($key) && strlen($key) == 256) { foreach (range("\x00", "\xFF") as $char) { if (substr_count($key, $char) == 0) { return FALSE; } } return TRUE; } return FALSE; } function _check_minor($key) { if (is_string($key) && strlen($key) == 64) { $indexs = array(); foreach (array_map("ord", str_split($key)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($indexs, ($byte >> $shift) & 3); } } $dict = array_count_values($indexs); foreach (range(0, 3) as $index) { if ($dict[$index] != 64) { return FALSE; } } return TRUE; } return FALSE; } /*************************************** Create encode maps for encode functions. ***************************************/ function _encode_map_1($major) { return array_map("ord", str_split($major)); } function _encode_map_2($minor) { $map_2 = array(array(), array(), array(), array()); $list = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($list, ($byte >> $shift) & 3); } } for ($byte = 0; $byte < 256; $byte++) { array_push($map_2[$list[$byte]], chr($byte)); } return $map_2; } /*************************************** Create decode maps for decode functions. ***************************************/ function _decode_map_1($minor) { $map_1 = array(); foreach (array_map("ord", str_split($minor)) as $byte) { foreach (range(6, 0, 2) as $shift) { array_push($map_1, ($byte >> $shift) & 3); } } return $map_1; }function _decode_map_2($major) { $map_2 = array(); $temp = array_map("ord", str_split($major)); for ($byte = 0; $byte < 256; $byte++) { $map_2[$temp[$byte]] = chr($byte); } return $map_2; } /*************************************** Encrypt or decrypt the string with maps. ***************************************/ function _encode($string, $map_1, $map_2) { $cache = ""; foreach (str_split($string) as $char) { $byte = $map_1[ord($char)]; foreach (range(6, 0, 2) as $shift) { $cache .= $map_2[($byte >> $shift) & 3][mt_rand(0, 63)]; } } return $cache; } function _decode($string, $map_1, $map_2) { $cache = ""; $temp = str_split($string); for ($iter = 0; $iter < strlen($string) / 4; $iter++) { $b12 = $map_1[ord($temp[$iter * 4])] << 6; $b34 = $map_1[ord($temp[$iter * 4 + 1])] << 4; $b56 = $map_1[ord($temp[$iter * 4 + 2])] << 2; $b78 = $map_1[ord($temp[$iter * 4 + 3])]; $cache .= $map_2[$b12 + $b34 + $b56 + $b78]; } return $cache; } /*************************************** This is the public interface for coding. ***************************************/ function encode_string($string, $major, $minor) { if (is_string($string)) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _encode_map_1($major); $map_2 = _encode_map_2($minor); return _encode($string, $map_1, $map_2); } } return FALSE; } function decode_string($string, $major, $minor) { if (is_string($string) && strlen($string) % 4 == 0) { if (_check_major($major) && _check_minor($minor)) { $map_1 = _decode_map_1($minor); $map_2 = _decode_map_2($major); return _decode($string, $map_1, $map_2); } } return FALSE; } ?> This is a sample showing how the code is being used. Hex editors may be of help with the input / output. Example <?php # get and process all of the form data @ $input = htmlspecialchars($_POST["input"]); @ $majorname = htmlspecialchars($_POST["majorname"]); @ $minorname = htmlspecialchars($_POST["minorname"]); @ $majorkey = htmlspecialchars($_POST["majorkey"]); @ $minorkey = htmlspecialchars($_POST["minorkey"]); @ $output = htmlspecialchars($_POST["output"]); # process the submissions by operation # CREATE @ $operation = $_POST["operation"]; if ($operation == "Create") { if (strlen($_POST["majorname"]) == 0) { $majorkey = bin2hex(crypt_major()); } if (strlen($_POST["minorname"]) == 0) { $minorkey = bin2hex(crypt_minor()); } if (strlen($_POST["majorname"]) != 0) { $majorkey = bin2hex(named_major($_POST["majorname"])); } if (strlen($_POST["minorname"]) != 0) { $minorkey = bin2hex(named_minor($_POST["minorname"])); } } # ENCRYPT or DECRYPT function is_hex($char) { if ($char == "0"): return TRUE; elseif ($char == "1"): return TRUE; elseif ($char == "2"): return TRUE; elseif ($char == "3"): return TRUE; elseif ($char == "4"): return TRUE; elseif ($char == "5"): return TRUE; elseif ($char == "6"): return TRUE; elseif ($char == "7"): return TRUE; elseif ($char == "8"): return TRUE; elseif ($char == "9"): return TRUE; elseif ($char == "a"): return TRUE; elseif ($char == "b"): return TRUE; elseif ($char == "c"): return TRUE; elseif ($char == "d"): return TRUE; elseif ($char == "e"): return TRUE; elseif ($char == "f"): return TRUE; else: return FALSE; endif; } function hex2bin($str) { if (strlen($str) % 2 == 0): $string = strtolower($str); else: $string = strtolower("0" . $str); endif; $cache = ""; $temp = str_split($str); for ($index = 0; $index < count($temp) / 2; $index++) { $h1 = $temp[$index * 2]; if (is_hex($h1)) { $h2 = $temp[$index * 2 + 1]; if (is_hex($h2)) { $cache .= chr(hexdec($h1 . $h2)); } else { return FALSE; } } else { return FALSE; } } return $cache; } if ($operation == "Encrypt" || $operation == "Decrypt") { # CHECK FOR ANY ERROR $errors = array(); if (strlen($_POST["input"]) == 0) { $output = ""; } $binmajor = hex2bin($_POST["majorkey"]); if (strlen($_POST["majorkey"]) == 0) { array_push($errors, "There must be a major key."); } elseif ($binmajor == FALSE) { array_push($errors, "The major key must be in hex."); } elseif (_check_major($binmajor) == FALSE) { array_push($errors, "The major key is corrupt."); } $binminor = hex2bin($_POST["minorkey"]); if (strlen($_POST["minorkey"]) == 0) { array_push($errors, "There must be a minor key."); } elseif ($binminor == FALSE) { array_push($errors, "The minor key must be in hex."); } elseif (_check_minor($binminor) == FALSE) { array_push($errors, "The minor key is corrupt."); } if ($_POST["operation"] == "Decrypt") { $bininput = hex2bin(str_replace("\r", "", str_replace("\n", "", $_POST["input"]))); if ($bininput == FALSE) { if (strlen($_POST["input"]) != 0) { array_push($errors, "The input data must be in hex."); } } elseif (strlen($bininput) % 4 != 0) { array_push($errors, "The input data is corrupt."); } } if (count($errors) != 0) { # ERRORS ARE FOUND $output = "ERROR:"; foreach ($errors as $error) { $output .= "\n" . $error; } } elseif (strlen($_POST["input"]) != 0) { # CONTINUE WORKING if ($_POST["operation"] == "Encrypt") { # ENCRYPT $output = substr(chunk_split(bin2hex(encode_string($_POST["input"], $binmajor, $binminor)), 58), 0, -2); } else { # DECRYPT $output = htmlspecialchars(decode_string($bininput, $binmajor, $binminor)); } } } # echo the form with the values filled echo "<P><TEXTAREA class=maintextarea name=input rows=25 cols=25>" . $input . "</TEXTAREA></P>\n"; echo "<P>Major Name:</P>\n"; echo "<P><INPUT id=textbox1 name=majorname value=\"" . $majorname . "\"></P>\n"; echo "<P>Minor Name:</P>\n"; echo "<P><INPUT id=textbox1 name=minorname value=\"" . $minorname . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Create name=operation>\n"; echo "</DIV>\n"; echo "<P>Major Key:</P>\n"; echo "<P><INPUT id=textbox1 name=majorkey value=\"" . $majorkey . "\"></P>\n"; echo "<P>Minor Key:</P>\n"; echo "<P><INPUT id=textbox1 name=minorkey value=\"" . $minorkey . "\"></P>\n"; echo "<DIV style=\"TEXT-ALIGN: center\"><INPUT class=submit type=submit value=Encrypt name=operation> \n"; echo "<INPUT class=submit type=submit value=Decrypt name=operation> </DIV>\n"; echo "<P>Result:</P>\n"; echo "<P><TEXTAREA class=maintextarea name=output rows=25 readOnly cols=25>" . $output . "</TEXTAREA></P></DIV></FORM>\n"; ?> What should be editted for better memory efficiency or faster execution?

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  • How to maintain encapsulation with composition in C++?

    - by iFreilicht
    I am designing a class Master that is composed from multiple other classes, A, Base, C and D. These four classes have absolutely no use outside of Master and are meant to split up its functionality into manageable and logically divided packages. They also provide extensible functionality as in the case of Base, which can be inherited from by clients. But, how do I maintain encapsulation of Master with this design? So far, I've got two approaches, which are both far from perfect: 1. Replicate all accessors: Just write accessor-methods for all accessor-methods of all classes that Master is composed of. This leads to perfect encapsulation, because no implementation detail of Master is visible, but is extremely tedious and makes the class definition monstrous, which is exactly what the composition should prevent. Also, adding functionality to one of the composees (is that even a word?) would require to re-write all those methods in Master. An additional problem is that inheritors of Base could only alter, but not add functionality. 2. Use non-assignable, non-copyable member-accessors: Having a class accessor<T> that can not be copied, moved or assigned to, but overrides the operator-> to access an underlying shared_ptr, so that calls like Master->A()->niceFunction(); are made possible. My problem with this is that it kind of breaks encapsulation as I would now be unable to change my implementation of Master to use a different class for the functionality of niceFunction(). Still, it is the closest I've gotten without using the ugly first approach. It also fixes the inheritance issue quite nicely. A small side question would be if such a class already existed in std or boost. EDIT: Wall of code I will now post the code of the header files of the classes discussed. It may be a bit hard to understand, but I'll give my best in explaining all of it. 1. GameTree.h The foundation of it all. This basically is a doubly-linked tree, holding GameObject-instances, which we'll later get to. It also has it's own custom iterator GTIterator, but I left that out for brevity. WResult is an enum with the values SUCCESS and FAILED, but it's not really important. class GameTree { public: //Static methods for the root. Only one root is allowed to exist at a time! static void ConstructRoot(seed_type seed, unsigned int depth); inline static bool rootExists(){ return static_cast<bool>(rootObject_); } inline static weak_ptr<GameTree> root(){ return rootObject_; } //delta is in ms, this is used for velocity, collision and such void tick(unsigned int delta); //Interaction with the tree inline weak_ptr<GameTree> parent() const { return parent_; } inline unsigned int numChildren() const{ return static_cast<unsigned int>(children_.size()); } weak_ptr<GameTree> getChild(unsigned int index) const; template<typename GOType> weak_ptr<GameTree> addChild(seed_type seed, unsigned int depth = 9001){ GOType object{ new GOType(seed) }; return addChildObject(unique_ptr<GameTree>(new GameTree(std::move(object), depth))); } WResult moveTo(weak_ptr<GameTree> newParent); WResult erase(); //Iterators for for( : ) loop GTIterator& begin(){ return *(beginIter_ = std::move(make_unique<GTIterator>(children_.begin()))); } GTIterator& end(){ return *(endIter_ = std::move(make_unique<GTIterator>(children_.end()))); } //unloading should be used when objects are far away WResult unloadChildren(unsigned int newDepth = 0); WResult loadChildren(unsigned int newDepth = 1); inline const RenderObject& renderObject() const{ return gameObject_->renderObject(); } //Getter for the underlying GameObject (I have not tested the template version) weak_ptr<GameObject> gameObject(){ return gameObject_; } template<typename GOType> weak_ptr<GOType> gameObject(){ return dynamic_cast<weak_ptr<GOType>>(gameObject_); } weak_ptr<PhysicsObject> physicsObject() { return gameObject_->physicsObject(); } private: GameTree(const GameTree&); //copying is only allowed internally GameTree(shared_ptr<GameObject> object, unsigned int depth = 9001); //pointer to root static shared_ptr<GameTree> rootObject_; //internal management of a child weak_ptr<GameTree> addChildObject(shared_ptr<GameTree>); WResult removeChild(unsigned int index); //private members shared_ptr<GameObject> gameObject_; shared_ptr<GTIterator> beginIter_; shared_ptr<GTIterator> endIter_; //tree stuff vector<shared_ptr<GameTree>> children_; weak_ptr<GameTree> parent_; unsigned int selfIndex_; //used for deletion, this isn't necessary void initChildren(unsigned int depth); //constructs children }; 2. GameObject.h This is a bit hard to grasp, but GameObject basically works like this: When constructing a GameObject, you construct its basic attributes and a CResult-instance, which contains a vector<unique_ptr<Construction>>. The Construction-struct contains all information that is needed to construct a GameObject, which is a seed and a function-object that is applied at construction by a factory. This enables dynamic loading and unloading of GameObjects as done by GameTree. It also means that you have to define that factory if you inherit GameObject. This inheritance is also the reason why GameTree has a template-function gameObject<GOType>. GameObject can contain a RenderObject and a PhysicsObject, which we'll later get to. Anyway, here's the code. class GameObject; typedef unsigned long seed_type; //this declaration magic means that all GameObjectFactorys inherit from GameObjectFactory<GameObject> template<typename GOType> struct GameObjectFactory; template<> struct GameObjectFactory<GameObject>{ virtual unique_ptr<GameObject> construct(seed_type seed) const = 0; }; template<typename GOType> struct GameObjectFactory : GameObjectFactory<GameObject>{ GameObjectFactory() : GameObjectFactory<GameObject>(){} unique_ptr<GameObject> construct(seed_type seed) const{ return unique_ptr<GOType>(new GOType(seed)); } }; //same as with the factories. this is important for storing them in vectors template<typename GOType> struct Construction; template<> struct Construction<GameObject>{ virtual unique_ptr<GameObject> construct() const = 0; }; template<typename GOType> struct Construction : Construction<GameObject>{ Construction(seed_type seed, function<void(GOType*)> func = [](GOType* null){}) : Construction<GameObject>(), seed_(seed), func_(func) {} unique_ptr<GameObject> construct() const{ unique_ptr<GameObject> gameObject{ GOType::factory.construct(seed_) }; func_(dynamic_cast<GOType*>(gameObject.get())); return std::move(gameObject); } seed_type seed_; function<void(GOType*)> func_; }; typedef struct CResult { CResult() : constructions{} {} CResult(CResult && o) : constructions(std::move(o.constructions)) {} CResult& operator= (CResult& other){ if (this != &other){ for (unique_ptr<Construction<GameObject>>& child : other.constructions){ constructions.push_back(std::move(child)); } } return *this; } template<typename GOType> void push_back(seed_type seed, function<void(GOType*)> func = [](GOType* null){}){ constructions.push_back(make_unique<Construction<GOType>>(seed, func)); } vector<unique_ptr<Construction<GameObject>>> constructions; } CResult; //finally, the GameObject class GameObject { public: GameObject(seed_type seed); GameObject(const GameObject&); virtual void tick(unsigned int delta); inline Matrix4f trafoMatrix(){ return physicsObject_->transformationMatrix(); } //getter inline seed_type seed() const{ return seed_; } inline CResult& properties(){ return properties_; } inline const RenderObject& renderObject() const{ return *renderObject_; } inline weak_ptr<PhysicsObject> physicsObject() { return physicsObject_; } protected: virtual CResult construct_(seed_type seed) = 0; CResult properties_; shared_ptr<RenderObject> renderObject_; shared_ptr<PhysicsObject> physicsObject_; seed_type seed_; }; 3. PhysicsObject That's a bit easier. It is responsible for position, velocity and acceleration. It will also handle collisions in the future. It contains three Transformation objects, two of which are optional. I'm not going to include the accessors on the PhysicsObject class because I tried my first approach on it and it's just pure madness (way over 30 functions). Also missing: the named constructors that construct PhysicsObjects with different behaviour. class Transformation{ Vector3f translation_; Vector3f rotation_; Vector3f scaling_; public: Transformation() : translation_{ 0, 0, 0 }, rotation_{ 0, 0, 0 }, scaling_{ 1, 1, 1 } {}; Transformation(Vector3f translation, Vector3f rotation, Vector3f scaling); inline Vector3f translation(){ return translation_; } inline void translation(float x, float y, float z){ translation(Vector3f(x, y, z)); } inline void translation(Vector3f newTranslation){ translation_ = newTranslation; } inline void translate(float x, float y, float z){ translate(Vector3f(x, y, z)); } inline void translate(Vector3f summand){ translation_ += summand; } inline Vector3f rotation(){ return rotation_; } inline void rotation(float pitch, float yaw, float roll){ rotation(Vector3f(pitch, yaw, roll)); } inline void rotation(Vector3f newRotation){ rotation_ = newRotation; } inline void rotate(float pitch, float yaw, float roll){ rotate(Vector3f(pitch, yaw, roll)); } inline void rotate(Vector3f summand){ rotation_ += summand; } inline Vector3f scaling(){ return scaling_; } inline void scaling(float x, float y, float z){ scaling(Vector3f(x, y, z)); } inline void scaling(Vector3f newScaling){ scaling_ = newScaling; } inline void scale(float x, float y, float z){ scale(Vector3f(x, y, z)); } void scale(Vector3f factor){ scaling_(0) *= factor(0); scaling_(1) *= factor(1); scaling_(2) *= factor(2); } Matrix4f matrix(){ return WMatrix::Translation(translation_) * WMatrix::Rotation(rotation_) * WMatrix::Scale(scaling_); } }; class PhysicsObject; typedef void tickFunction(PhysicsObject& self, unsigned int delta); class PhysicsObject{ PhysicsObject(const Transformation& trafo) : transformation_(trafo), transformationVelocity_(nullptr), transformationAcceleration_(nullptr), tick_(nullptr) {} PhysicsObject(PhysicsObject&& other) : transformation_(other.transformation_), transformationVelocity_(std::move(other.transformationVelocity_)), transformationAcceleration_(std::move(other.transformationAcceleration_)), tick_(other.tick_) {} Transformation transformation_; unique_ptr<Transformation> transformationVelocity_; unique_ptr<Transformation> transformationAcceleration_; tickFunction* tick_; public: void tick(unsigned int delta){ tick_ ? tick_(*this, delta) : 0; } inline Matrix4f transformationMatrix(){ return transformation_.matrix(); } } 4. RenderObject RenderObject is a base class for different types of things that could be rendered, i.e. Meshes, Light Sources or Sprites. DISCLAIMER: I did not write this code, I'm working on this project with someone else. class RenderObject { public: RenderObject(float renderDistance); virtual ~RenderObject(); float renderDistance() const { return renderDistance_; } void setRenderDistance(float rD) { renderDistance_ = rD; } protected: float renderDistance_; }; struct NullRenderObject : public RenderObject{ NullRenderObject() : RenderObject(0.f){}; }; class Light : public RenderObject{ public: Light() : RenderObject(30.f){}; }; class Mesh : public RenderObject{ public: Mesh(unsigned int seed) : RenderObject(20.f) { meshID_ = 0; textureID_ = 0; if (seed == 1) meshID_ = Model::getMeshID("EM-208_heavy"); else meshID_ = Model::getMeshID("cube"); }; unsigned int getMeshID() const { return meshID_; } unsigned int getTextureID() const { return textureID_; } private: unsigned int meshID_; unsigned int textureID_; }; I guess this shows my issue quite nicely: You see a few accessors in GameObject which return weak_ptrs to access members of members, but that is not really what I want. Also please keep in mind that this is NOT, by any means, finished or production code! It is merely a prototype and there may be inconsistencies, unnecessary public parts of classes and such.

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  • Why am I getting an error when return TRUE/FALSE to type Boolean?

    - by phill
    I wrote the following code: import java.lang.*; import DB.*; private Boolean validateInvoice(String i) { int count = 0; try { //check how many rowsets ResultSet c = connection.DBquery("select count(*) from Invce i,cust c where tranid like '"+i+"' and i.key = c.key "); while (c.next()) { System.out.println("rowcount : " + c.getInt(1)); count = c.getInt(1); } if (count > 0 ) { return TRUE; } else { return FALSE; } //end if } catch(Exception e){e.printStackTrace();return FALSE;} } The errors I'm getting are: i.java:195: cannot find symbol symbol : variable TRUE location: class changei.iTable return TRUE; i.java:197: cannot find symbol symbol : variable TRUE location: class changei.iTable return FALSE; i.java:201:: cannot find symbol symbol : variable FALSE location: class changei.iTable catch(Exception e){e.printStackTrace();return FALSE;} The Connection class comes from the DB package i created. Is the return TRUE/FALSE correct since the function is a Boolean return type?

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