from string import atol, join

# by Bram Cohen
# this file is public domain

hexes = ['00', '01', '02', '03', '04', '05', '06', '07', '08', '09', '0a', '0b', '0c', '0d', '0e', '0f',
         '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '1a', '1b', '1c', '1d', '1e', '1f',
         '20', '21', '22', '23', '24', '25', '26', '27', '28', '29', '2a', '2b', '2c', '2d', '2e', '2f',
         '30', '31', '32', '33', '34', '35', '36', '37', '38', '39', '3a', '3b', '3c', '3d', '3e', '3f',
         '40', '41', '42', '43', '44', '45', '46', '47', '48', '49', '4a', '4b', '4c', '4d', '4e', '4f',
         '50', '51', '52', '53', '54', '55', '56', '57', '58', '59', '5a', '5b', '5c', '5d', '5e', '5f',
         '60', '61', '62', '63', '64', '65', '66', '67', '68', '69', '6a', '6b', '6c', '6d', '6e', '6f',
         '70', '71', '72', '73', '74', '75', '76', '77', '78', '79', '7a', '7b', '7c', '7d', '7e', '7f',
         '80', '81', '82', '83', '84', '85', '86', '87', '88', '89', '8a', '8b', '8c', '8d', '8e', '8f',
         '90', '91', '92', '93', '94', '95', '96', '97', '98', '99', '9a', '9b', '9c', '9d', '9e', '9f',
         'a0', 'a1', 'a2', 'a3', 'a4', 'a5', 'a6', 'a7', 'a8', 'a9', 'aa', 'ab', 'ac', 'ad', 'ae', 'af',
         'b0', 'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7', 'b8', 'b9', 'ba', 'bb', 'bc', 'bd', 'be', 'bf',
         'c0', 'c1', 'c2', 'c3', 'c4', 'c5', 'c6', 'c7', 'c8', 'c9', 'ca', 'cb', 'cc', 'cd', 'ce', 'cf',
         'd0', 'd1', 'd2', 'd3', 'd4', 'd5', 'd6', 'd7', 'd8', 'd9', 'da', 'db', 'dc', 'dd', 'de', 'df',
         'e0', 'e1', 'e2', 'e3', 'e4', 'e5', 'e6', 'e7', 'e8', 'e9', 'ea', 'eb', 'ec', 'ed', 'ee', 'ef',
         'f0', 'f1', 'f2', 'f3', 'f4', 'f5', 'f6', 'f7', 'f8', 'f9', 'fa', 'fb', 'fc', 'fd', 'fe', 'ff']

def int_to_binary(numin, size, big_endian = 1):
    num = numin
    if num < 0:
        raise ValueError('Binary conversion only supports nonnegative, got ' + str(num))
    b = []
    ss = 0
    while num > 0:
        b.append(chr(num & 0xFF))
        num = num >> 8
    if len(b) > size:
        raise ValueError('num ' + str(numin) + ' longer than ' + str(size))
    b.append(chr(0) * (size - len(b)))
    r = join(b, '')
    if big_endian:
        return reverse_string(r)
    return r

def binary_to_int(s, big_endian = 1):
    if not big_endian:
        s = reverse_string(s)
    return atol(join(map(lambda x, h = hexes: h[ord(x)], list(s)), ''), 16)

def reverse_string(s):
    l = list(s)
    l.reverse()
    return join(l, '')

def test():
    assert binary_to_int(chr(0)) == 0
    assert binary_to_int(chr(1)) == 1
    assert binary_to_int(chr(0) + chr(1)) == 1
    assert binary_to_int(chr(1) + chr(0)) == 256
    assert len(int_to_binary(0, 5)) == 5
    assert len(int_to_binary(1, 5)) == 5
    assert binary_to_int(int_to_binary(10 ** 8, 20)) == 10 ** 8
    assert binary_to_int(int_to_binary(10 ** 8, 20, 0), 0) == 10 ** 8
    assert int_to_binary(binary_to_int('abc'), 3) == 'abc'
    assert int_to_binary(binary_to_int('a' * 16), 16) == 'a' * 16