gistfile1.txt

import math
import sys
import uuid

# this is taken from: https://gist.github.com/bhelx/778542
# modified to support long
class UrlShortener:
    BASE = 62
    UPPERCASE_OFFSET = 55
    LOWERCASE_OFFSET = 61
    DIGIT_OFFSET = 48

    @staticmethod
    def true_ord(char):
        """
        Turns a digit [char] in character representation
        from the number system with base [BASE] into an integer.
        """

        if char.isdigit():
            return ord(char) - UrlShortener.DIGIT_OFFSET
        elif 'A' <= char <= 'Z':
            return ord(char) - UrlShortener.UPPERCASE_OFFSET
        elif 'a' <= char <= 'z':
            return ord(char) - UrlShortener.LOWERCASE_OFFSET
        else:
            raise ValueError("%s is not a valid character" % char)

    @staticmethod
    def true_chr(integer):
        """
        Turns an integer [integer] into digit in base [BASE]
        as a character representation.
        """
        if integer < 10:
            return chr(integer + UrlShortener.DIGIT_OFFSET)
        elif 10 <= integer <= 35:
            return chr(integer + UrlShortener.UPPERCASE_OFFSET)
        elif 36 <= integer < 62:
            return chr(integer + UrlShortener.LOWERCASE_OFFSET)
        else:
            raise ValueError("%d is not a valid integer in the range of base %d" % (integer, UrlShortener.BASE))

    @staticmethod
    def saturate(key):
        """
        Turn the base [BASE] number [key] into an integer
        """
        int_sum = 0
        reversed_key = key[::-1]
        for idx, char in enumerate(reversed_key):
            int_sum += UrlShortener.true_ord(char) * (UrlShortener.BASE ** idx)  # don't use math.pow, use python built-in pow to handle large int
        return int_sum

    @staticmethod
    def dehydrate(integer):
        """
        Turn an integer [integer] into a base [BASE] number
        in string representation
        """

        # we won't step into the while if integer is 0
        # so we just solve for that case here
        if integer == 0:
            return '0'

        string = ""
        while integer > 0:
            remainder = integer % UrlShortener.BASE
            string = UrlShortener.true_chr(remainder) + string
            integer /= UrlShortener.BASE
        return string