HashBuilder

Latest	1.0.1
Homepage	https://github.com/levigroker/HashBuilder
License	Creative Commons Attribution 3.0 Unported License
Platforms	ios 5.0, osx 10.7, requires ARC
Frameworks	Foundation
Authors	Levi Brown

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Used to build a hash result from contributed objects or hashes (presumably
properties on your object which should be considered in the isEqual: override).
The intention is for the hash result to be returned from an override to the
NSObject - (NSUInteger)hash method.

Installing

If you’re using CocoPods it’s as simple as adding this to your Podfile:

pod 'HashBuilder', '~> 1.0'

otherwise, simply add the contents of the HashBuilder subdirectory to your
project.

Documentation

To use, create a HashBuilder object, contribute to it, then query the ‘builtHash’
property for the resulting hash.

- (NSUInteger)hash
{
    HashBuilder *builder = [HashBuilder builder];

    [builder contributeObject:self.objectID];
    [builder contributeObject:self.occurredDate];
    [builder contributeObject:self.type];
    [builder contributeObject:self.objectURL];
    [builder contributeObject:self.tags];
    [builder contributeObject:self.count];

    NSUInteger retVal = builder.builtHash;

    return retVal;
}

It is prudent to consider the same properties when overriding your - (BOOL)isEqual:(id)object
method as well.

NOTE: The order of contribution will change the resulting hash, even if all
the same values are contributed. For example:

HashBuilder *builder1 = [HashBuilder builder];
[builder1 contributeObject:@"a"];
[builder1 contributeObject:[NSNumber numberWithInteger:12345]];
NSUInteger hash1 = builder1.builtHash;

HashBuilder *builder2 = [HashBuilder builder];
[builder2 contributeObject:[NSNumber numberWithInteger:12345]];
[builder2 contributeObject:@"a"];
NSUInteger hash2 = builder2.builtHash;

hash1 != hash2

Disclaimer and Licence

• This work makes use of techniques and concepts presented by Mike Ash
  in his post entitled Implementing Equality and Hashing
• This work is licensed under the Creative Commons Attribution 3.0 Unported License.
  Please see the included LICENSE.txt for complete details.

About

A professional iOS engineer by day, my name is Levi Brown. Authoring a technical
blog grokin.gs, I am reachable via:

Twitter @levigroker
EMail [email protected]

Your constructive comments and feedback are always welcome.

Latest podspec

{
    "name": "HashBuilder",
    "version": "1.0.1",
    "summary": "A utility to generate a hash for NSObject subclasses.",
    "description": "Used to build a hash result from contributed objects or hashes (presumablynproperties on your object which should be considered in the isEqual: override).nThe intention is for the hash result to be returned from an override to then`NSObject` `- (NSUInteger)hash` method.",
    "homepage": "https://github.com/levigroker/HashBuilder",
    "license": "Creative Commons Attribution 3.0 Unported License",
    "authors": {
        "Levi Brown": "[email protected]"
    },
    "social_media_url": "https://twitter.com/levigroker",
    "source": {
        "git": "https://github.com/levigroker/HashBuilder.git",
        "tag": "1.0.1"
    },
    "platforms": {
        "ios": "5.0",
        "osx": "10.7"
    },
    "source_files": "HashBuilder/**/*.{h,m}",
    "frameworks": "Foundation",
    "requires_arc": true
}

Wed, 02 Mar 2016 06:41:03 +0000