discourse/lib/base62.rb

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# frozen_string_literal: true
# Modified version of: https://github.com/steventen/base62-rb
module Base62
KEYS ||= "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
2018-01-19 13:52:42 -05:00
KEYS_HASH ||= KEYS.each_char.with_index.to_h
BASE ||= KEYS.length
# Encodes base10 (decimal) number to base62 string.
def self.encode(num)
return "0" if num == 0
return nil if num < 0
str = ""
while num > 0
# prepend base62 charaters
str = KEYS[num % BASE] + str
num = num / BASE
end
str
end
# Decodes base62 string to a base10 (decimal) number.
def self.decode(str)
num = 0
i = 0
len = str.length - 1
# while loop is faster than each_char or other 'idiomatic' way
while i < str.length
pow = BASE**(len - i)
num += KEYS_HASH[str[i]] * pow
i += 1
end
num
end
end