InfiniteEnumFlags

Introduction

Dotnet Enum has an [Flags] attribute that gives us the ability to have a binary enum system and use bitwise operators. However, enum specifically restricts to built-in numeric types which is a big problem because it is limited to 2^32 for int values which means we only can have a maximum of 32 items in our enum or 2^64 for long which limits us to a maximum of 64 items.

this library aims to remove these restrictions and still give us the same functionality.

Getting started

To define an enum class, you can create a class/record and inherit it from InfiniteEnum<ClassName>, this base class, will help you to access the list of defined enum items. then by adding static fields of type Flag<ClassName> you can create your enums. setting the values is imperative to provide values as powers of two.

e.g

public class Features : InfiniteEnum<Features>
{
    public static readonly Flag<Features> None = new(-1);  // 0  - 0
    public static readonly Flag<Features> F1 = new(0);     // 1  - 1
    public static readonly Flag<Features> F2 = new(1);     // 2  - 10
    public static readonly Flag<Features> F3 = new(2);     // 4  - 100
    public static readonly Flag<Features> F4 = new(3);     // 8  - 1000
    public static readonly Flag<Features> F5 = new(4);     // 16 - 10000
    public static readonly Flag<Features> F6 = new(5);     // 32 - 100000
    public static readonly Flag<Features> F7 = new(6);     // 64 - 1000000
    public static readonly Flag<Features> F8 = new(7);     // 128 - 10000000

    // We can support up to 2,147,483,647 items
}

Usage

To use your custom enum, it is important to be familiar with the built-in dotnet enum flags capabilities because the functionalities are almost identical. for example we can use all bitwise operators (|,&,~,^) in our custom enum.

e.g

var features = Features.F1 | Features.F3;  // F1 + F3

Alternatively, If you don't like bitwise Operators, you can use the Flag<> extension methods:

Name	Description
HasFlag	Check whatever enum has an specific flag or not, (bitwise &)
SetFlag	Add/Set specific flag(s) to an enum, (bitwise or)
UnsetFlag	Remove/Unset specific flag(s) from an enum (bitwise &~)
ToggleFlag	It toggles flag(s) from an enum (bitwise ^)

e.g

var features = Features.F1.SetFlag(Features.F3);
features.HasFlag(Features.F2); // false

Storing Flag's value

Since we want to support more than 32 items in our enums, we can not store an integer value, luckily we can use ToUniqueId() function to get a unique base64 key, and to convert it back to an Flag, we can use FromUniqueId() static method.

var features = Features.F1 | Features.F3; 
string id = features.ToUniqueId();
var new_features = Features.FromUniqueId(id); 
Console.WriteLine(features == new_features); // true

Example

One of the reasonable use cases that shows why we need this library is developing a flexible authorization in asp.net core applications that @Json Taylor presented very well in this video. However, his implementation using dotnet [Flags] had a massive limitation in big projects when we need more than 64 permissions. I provided an example of the same demo in the video using InfiniteEnumFlags that doesn't have these limitations.

To see flexible aspnetcore authorization example using InfiniteEnumFlags, first clone the repo using below command

 git clone --recurse-submodules https://github.com/alirezanet/InfiniteEnumFlags.git

then you can open \InfiniteEnumFlags\Example\flexible-aspnetcore-authorization\FlexibleAuth\FlexibleAuth.sln and then run the Server project.

Admin Username: admin@localhost

Auditor Username: auditor@localhost

Default Password: Password123!

Support

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Contribution

Feel free to send me a pull request!

License

MIT