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"""Convert strings to numbers and numbers to strings.
Gustavo Picon
https://tabo.pe/projects/numconv/
"""
__version__ = "2.1.1"
# from april fool's rfc 1924
BASE85 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~"
# rfc4648 alphabets
BASE16 = BASE85[:16]
BASE32 = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
BASE32HEX = BASE85[:32]
BASE64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
BASE64URL = BASE64[:62] + "-_"
# http://en.wikipedia.org/wiki/Base_62 useful for url shorteners
BASE62 = BASE85[:62]
class NumConv:
"""Class to create converter objects.
:param radix: The base that will be used in the conversions.
The default value is 10 for decimal conversions.
:param alphabet: A string that will be used as a encoding alphabet.
The length of the alphabet can be longer than the radix. In this
case the alphabet will be internally truncated.
The default value is :data:`numconv.BASE85`
:raise TypeError: when *radix* isn't an integer
:raise ValueError: when *radix* is invalid
:raise ValueError: when *alphabet* has duplicated characters
"""
def __init__(self, radix=10, alphabet=BASE85):
"""basic validation and cached_map storage"""
if int(radix) != radix:
raise TypeError("radix must be an integer")
if not 2 <= radix <= len(alphabet):
raise ValueError("radix must be >= 2 and <= %d" % (len(alphabet),))
self.radix = radix
self.alphabet = alphabet
self.cached_map = dict(zip(self.alphabet, range(len(self.alphabet))))
if len(self.cached_map) != len(self.alphabet):
raise ValueError("duplicate characters found in '%s'" % (self.alphabet,))
def int2str(self, num):
"""Converts an integer into a string.
:param num: A numeric value to be converted to another base as a
string.
:rtype: string
:raise TypeError: when *num* isn't an integer
:raise ValueError: when *num* isn't positive
"""
if int(num) != num:
raise TypeError("number must be an integer")
if num < 0:
raise ValueError("number must be positive")
radix, alphabet = self.radix, self.alphabet
if radix in (8, 10, 16) and alphabet[:radix].lower() == BASE85[:radix].lower():
return ({8: "%o", 10: "%d", 16: "%x"}[radix] % num).upper()
ret = ""
while True:
ret = alphabet[num % radix] + ret
if num < radix:
break
num //= radix
return ret
def str2int(self, num):
"""Converts a string into an integer.
If possible, the built-in python conversion will be used for speed
purposes.
:param num: A string that will be converted to an integer.
:rtype: integer
:raise ValueError: when *num* is invalid
"""
radix, alphabet = self.radix, self.alphabet
if radix <= 36 and alphabet[:radix].lower() == BASE85[:radix].lower():
return int(num, radix)
ret = 0
lalphabet = alphabet[:radix]
for char in num:
if char not in lalphabet:
raise ValueError("invalid literal for radix2int() with radix %d: '%s'" % (radix, num))
ret = ret * radix + self.cached_map[char]
return ret
def int2str(num, radix=10, alphabet=BASE85):
"""helper function for quick base conversions from integers to strings"""
return NumConv(radix, alphabet).int2str(num)
def str2int(num, radix=10, alphabet=BASE85):
"""helper function for quick base conversions from strings to integers"""
return NumConv(radix, alphabet).str2int(num)
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