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Posts Tagged ‘algorithms’

Number Base Converter, converts numbers from any base to decimal and vice-versa

December 27th, 2009 Yervand Aghababyan No comments

Keep in mind that if you just want to address some URL in a short way then you don’t really need to read this article. You just have to use one of the multitude of services which provide URL mapping to tiny, generated URLs. Some of those services are: http://tinyurl.com/, http://u.nu/, http://bit.ly/. Just use the one you find the sexiest ;)

What i needed was a way to make URLs on my website as short as possible. I had a huge list of numbered entries each of which had it’s own unique ID and a URL looking like this: mywebsite.com/entries/789465479916 .  The best way of making the last number part of the URL as short as possible i found is converting the huge decimal number to the base of 62. Why 62? Because we’ve got 62 alphanumerical symbols there (0-9a-zA-Z) !

The first thing i found after some googling is that php actually provides a function named base_convert() which does what i want. BUT! It doesn’t support base of 62 and really huge numbers. A little disappointed i left this function be and resumed my search of the ideal solution! :D

In the comments of base_convert() i found a wonderful comment doing nearly exactly what i want. The only bad thing about it was that it didn’t support bug numbers. So i modified the code to use the bcmath php extension which provides support of huge number calculations. Bellow is the modified code.

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