https://github.com/kbilsted/autohasher

Automatic generation of GetHashCode() methods using run-time code generation.
https://github.com/kbilsted/autohasher

Last synced: 1 day ago
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Automatic generation of GetHashCode() methods using run-time code generation.

• Host: GitHub
• URL: https://github.com/kbilsted/autohasher
• Owner: kbilsted
• License: apache-2.0
• Created: 2014-09-21T19:16:04.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2015-04-23T21:18:08.000Z (over 9 years ago)
• Last Synced: 2024-11-02T07:40:04.028Z (5 days ago)
• Language: C#
• Homepage:
• Size: 299 KB
• Stars: 6
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# AutoHasher

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[![Nuget](https://img.shields.io/nuget/dt/autohasher.svg)](http://nuget.org/packages/autohasher)

[![Nuget](https://img.shields.io/nuget/v/autohasher.svg)](http://nuget.org/packages/autohasher)

[![Nuget](https://img.shields.io/nuget/vpre/autohasher.svg)](http://nuget.org/packages/autohasher)

Automatic generation of GetHashCode() methods using on the fly run-time code generation.

# 1. Advantages

Using this framework is a real treat. Here is what you get:

* *Productivity!* You are guaranteed to generate a sound hash code. No more forgetting to update your hash code methods when adding or removing fields from your classes!

* This framework run-time generates code that is *as fast as hand coded implementations. Sometimes even faster* since we utilize some optimization tricks. 

* You are automatically ensured to follow *best practices*- such as calculating inside an 'unchecked' block.

* Automatic null handling.

* Use the same implementation everywhere. Set up your editor to automatically insert the GetHashCode() when creating new classes. 

# 2. Usage

### 1. Define a class

```C#

using AutoHash;

using AutoHash.Attributes;

class Foo

{

  internal string field1 = "foo";

  internal int bar = 42;

  internal List l1 = null;

  internal List l2 = new List() { 0, 0 };

  [DontHash]

  internal string nonHashed = "boo";

}

```

  

### 2. Implement GetHashCode() the same way for all classes

    

```C#

public override int GetHashCode()

{

  return AutoHasher.GetHashCode(this);

}

```  

### 3. Check that it works

```C#

[TestFixture]

class UsageTest

{

  [Test]

  public void TestUsage()

  {

    var foo = new Foo();

    int expected = 0;

    expected = (expected * 397) ^ foo.field1.GetHashCode();

    expected = (expected * 397) ^ foo.bar.GetHashCode();

    expected = (expected * 397) ^ foo.l2.Count.GetHashCode();

    int actual = foo.GetHashCode();

    

    Assert.AreEqual(expected, actual);

  }

}

```

Notice that the field 'nonHashed' is not part of the hash code, and the collections are only participating with their length.