# Creating InsensitiveHash in C

**URL:** <https://www.ruby-forum.com/t/creating-insensitivehash-in-c/160807>\
**Category:** Ruby\
**Created:** [February 19, 2009, 9:58pm UTC](https://www.ruby-forum.com/t/creating-insensitivehash-in-c/160807 "2009-02-19T21:58:31Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\
**Post date:** [February 19, 2009, 9:58pm UTC](https://www.ruby-forum.com/t/creating-insensitivehash-in-c/160807/1 "2009-02-19T21:58:31Z")

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Hi, I’d like a faster Ruby class same as Hash but in which key and value  
are  
insensitive, so:

* * *

params = InsensitiveHash.new  
params[“q”] = 0.5  
params[“transport”] = “TCP”

params[“Q”]  
=\> 0.5

## params[“Transport”] == “tcp” =\> true

It will be used extensively so I need it being very fast. I’m thinking  
in  
implementing it as a new Ruby class in C, modifying Hash class.

Do you think it’s feasible? Any suggestion?  
Thanks a lot.

PD: Where is the C file defining Hash class? I read “hash.c” in Hash  
documentation:  
[class Hash - RDoc Documentation](http://www.ruby-doc.org/core/classes/Hash.html)  
but I can’t find it in Ruby libs directory.

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**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\
**Post date:** [February 19, 2009, 10:23pm UTC](https://www.ruby-forum.com/t/creating-insensitivehash-in-c/160807/2 "2009-02-19T22:23:53Z")

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On Thu, Feb 19, 2009 at 3:57 PM, Iñaki Baz C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
wrote:

> =\> 0.5
> 
> PD: Where is the C file defining Hash class? I read “hash.c” in Hash  
> documentation:  
> [class Hash - RDoc Documentation](http://www.ruby-doc.org/core/classes/Hash.html)  
> but I can’t find it in Ruby libs directory.

You won’t find it in a runtime installation of Ruby. The file hash.h is  
in  
the top level directory of the Ruby source code.

That said, If all you want to do is to make the keys case insensitive, a  
naive Ruby implementation is likely to be almost as fast as anything you  
could do in C, since the time intensitve implementation parts of Hash  
are  
already in C.

So something like

class InsensitiveHash  
def initialize  
@hash = {}  
end

def [](key}  
@hash[key.downcase]  
end

def []=(key, value)  
@hash[key.downcase] = value  
end  
end

And yes, I’d recommend having the InsensitiveHash have an instance of  
Hash  
rather than being a subclass of Hash.

–  
Rick DeNatale

Blog: [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/)  
Twitter: [http://twitter.com/RickDeNatale](http://twitter.com/RickDeNatale)  
WWR: [http://www.workingwithrails.com/person/9021-rick-denatale](http://www.workingwithrails.com/person/9021-rick-denatale)  
LinkedIn: [http://www.linkedin.com/in/rickdenatale](http://www.linkedin.com/in/rickdenatale)

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**Author:** ![ISSSSaki\_Baz\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/51bf81/32.png) [@ISSSSaki\_Baz\_C](https://www.ruby-forum.com/u/ISSSSaki_Baz_C)\
**Post date:** [February 19, 2009, 10:33pm UTC](https://www.ruby-forum.com/t/creating-insensitivehash-in-c/160807/3 "2009-02-19T22:33:54Z")

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El Jueves, 19 de Febrero de 2009, Rick DeNatale escribió:

> Â Â Â @hash[key.downcase] = value  
> Â Â end  
> end
> 
> And yes, I’d recommend having the InsensitiveHash have an instance of Hash  
> rather than being a subclass of Hash.

The fact is I already have something as above, but I wonder if using a  
new  
Ruby C native class would be _really_ faster.

Thanks a lot.