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Showing posts from July 24, 2021

Base/Base62 encoding with Java

Greetings! Converting base 10 number to another base is a common mathematical operation. First of all, why do we need base62? Shorten a given URL Saving a file using timestamp Short text As the base62 has lot more characters, we can easily create a small version of a given number. Let's do the Math Converting to another base has common steps. ( base-10-to-other-bases ) Divide the number by the base and get the remainder. Divide the quotient and get the remainder. Continue this process untill the quotient is zero. Order the remainders from last to first. We can try this process for hexa-decimal. As hexa-decimal is 16 chars, we need a way to represent that value. For that 0123456789ABCDEF are used. 42 42 / 16 = remainder 10, quotient 2 2 / 16 = remainder 2, quotient 0 Since 10 is A in hexa representation 42 = 2A in hexa-decimal number system. This same logic is applied for Base62. We can use 0-9A-Za-z characters to encoe base62. 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopq