36 lines
857 B
Ruby
36 lines
857 B
Ruby
# Modified version of: https://github.com/steventen/base62-rb
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module Base62
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KEYS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".freeze
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KEYS_HASH = KEYS.each_char.with_index.inject({}) { |h, (k, v)| h[k] = v; h }
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BASE = KEYS.length
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# Encodes base10 (decimal) number to base62 string.
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def self.encode(num)
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return "0" if num == 0
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return nil if num < 0
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str = ""
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while num > 0
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# prepend base62 charaters
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str = KEYS[num % BASE] + str
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num = num / BASE
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end
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str
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end
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# Decodes base62 string to a base10 (decimal) number.
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def self.decode(str)
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num = 0
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i = 0
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len = str.length - 1
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# while loop is faster than each_char or other 'idiomatic' way
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while i < str.length
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pow = BASE**(len - i)
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num += KEYS_HASH[str[i]] * pow
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i += 1
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end
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num
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end
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end
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