Skip to main content

How to store an array of booleans in a int

Uneori ajungem sa ne dorim sa stocam intr-un int mai multe valori booleene( de obicei de dragul artei) pentru a salva a avea mesajele care se trimit pe tiava cat mai mici. O solutie pe care o propun este sa folosim BitArray.
Acesta ne permite sa lucram cu biti. Pentru a initializa si seta valoriile unui BitArray trebuie sa scriem urmatorul cod:  
BitArray bits = new BitArray(32); // 32 - numarul de biti pe care il ocupa un int 
bits[0] = true;
...
bits[31] = false; 
Urmatorul pas este sa convertim un BitArray in int. Acest lucru se face destul de usor cu metoda CopyTo:  
int[] valueConverted = new int[1];
bits.CopyTo(valueConverted,0); // 0 - reprezinta indexul de inceput 
int result = valueConverted[0]; 
In result am obtinut int-ul care contine BitArrat-ul nostru.Pentru a executa procesul invers, sa obtinem un BitArray dintr-un int este nevoie sa apelam metoda statica GetBytes a clasei BitConverter.  
BitArray bits = BitConverter.GetBytes(result); 
Ce alta solutie aveti pentru aceast task?

Comments

  1. In functie de context, as folosi Enum-uri decorate cu [Flags]. Sint mult mai intuitive, in ciuda suportului dectul de slab de lucru cu ei in C#. Sincer, nici nu stiam de BitArray. Mersi.

    ReplyDelete
  2. Eh, bitarrays, flags.. :)
    Ne obisnuim lenesi si uitam de un banal
    int bits |= 1 << pos;
    ca sa "stocam" un bit
    si (bits & 1< 0
    ca sa ii aflam valoarea..

    ;)

    ReplyDelete
  3. Normal, mai sus corect era:
    int bits = 0;
    bits |= 1 << pos;
    if (bits & (1 << pos) != 0) ...

    ReplyDelete

Post a Comment

Popular posts from this blog

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine:
threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration:

TeamCity.NET 4.51EF 6.0.2VS2013
It seems that there …

Fundamental Books of a Software Engineer (version 2018)

More then six years ago I wrote a blog post about fundamental books that any software engineer (developer) should read. Now it is an excellent time to update this list with new entries.

There are 5 different categories of books, that represent the recommended path. For example, you start with Coding books, after that, you read books about Programming, Design and so on.
There are some books about C++ that I recommend not because you shall know C++, only because the concepts that you can learn from it.

Coding

Writing solid codeCode completeProgramming Pearls, more programming pearls(recommended)[NEW] Introduction to Algorithms

Programming

Refactoring (M. Fowler)Pragmatic ProgrammerClean code[NEW] Software Engineering: A Practitioner's Approach[NEW] The Mythical Man-Month[NEW] The Art of Computer Programming

Design

Applying UML and Patterns (GRASP patterns)C++ coding standards (Sutter, Alexandrescu)The C++ programming language (Stroustrup, Part IV)Object-oriented programming (Peter Coad)P…