1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
# isan.py - functions for handling International Standard Audiovisual Numbers
# (ISANs)
#
# Copyright (C) 2010, 2011, 2012, 2013 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
"""ISAN (International Standard Audiovisual Number).
The ISAN (International Standard Audiovisual Number) is used to identify
audiovisual works.
The number is hexadecimal and can consists of at least a root identifier,
and an episode or part. After that an optional check digit, optional
version and optionally another check digit can be provided. The check
digits are validated using the ISO 7064 Mod 37, 36 algorithm.
>>> validate('000000018947000000000000')
'000000018947000000000000'
>>> compact('0000-0000-D07A-0090-Q-0000-0000-X')
'00000000D07A009000000000'
>>> validate('0000-0001-8CFA-0000-I-0000-0000-K')
'000000018CFA0000I00000000K'
>>> validate('0000-0001-8CFA-0000-A-0000-0000-K')
Traceback (most recent call last):
...
InvalidChecksum: ...
>>> format('000000018947000000000000')
'0000-0001-8947-0000-8-0000-0000-D'
>>> to_urn('00000000D07A009000000000')
'URN:ISAN:0000-0000-D07A-0090-Q-0000-0000-X'
>>> to_xml('1881-66C7-3420-6541-Y-9F3A-0245-O')
'<ISAN root="1881-66C7-3420" episode="6541" version="9F3A-0245" />'
"""
from stdnum.exceptions import *
from stdnum.iso7064 import mod_37_36
from stdnum.util import clean
def split(number):
"""Split the number into a root, an episode or part, a check digit a
version and another check digit. If any of the parts are missing an empty
string is returned."""
number = clean(number, ' -').strip().upper()
if len(number) == 17 or len(number) == 26:
return number[0:12], number[12:16], number[16], number[17:25], number[25:]
elif len(number) > 16:
return number[0:12], number[12:16], '', number[16:24], number[24:]
else:
return number[0:12], number[12:16], number[16:], '', ''
def compact(number, strip_check_digits=True):
"""Convert the ISAN to the minimal representation. This strips the number
of any valid separators and removes surrounding whitespace. The check
digits are removed by default."""
number = list(split(number))
if strip_check_digits:
number[2] = number[4] = ''
return ''.join(number)
def validate(number, strip_check_digits=False, add_check_digits=False):
"""Check if the number provided is a valid ISAN. If check digits are
present in the number they are validated. If strip_check_digits is True
any existing check digits will be removed (after checking). If
add_check_digits is True the check digit will be added if they are not
present yet."""
(root, episode, check1, version, check2) = split(number)
# check digits used
for x in root + episode + version:
if x not in '0123456789ABCDEF':
raise InvalidFormat()
# check length of all components
if len(root) != 12 or len(episode) != 4 or len(check1) not in (0, 1) or \
len(version) not in (0, 8) or len(check1) not in (0, 1):
raise InvalidLength()
# allow removing check digits
if strip_check_digits:
check1 = check2 = ''
# check check digits
if check1:
mod_37_36.validate(root + episode + check1)
if check2:
mod_37_36.validate(root + episode + version + check2)
# add check digits
if add_check_digits and not check1:
check1 = mod_37_36.calc_check_digit(root + episode)
if add_check_digits and not check2 and version:
check2 = mod_37_36.calc_check_digit(root + episode + version)
return root + episode + check1 + version + check2
def is_valid(number):
"""Check if the number provided is a valid ISAN. If check digits are
present in the number they are validated."""
try:
return bool(validate(number))
except ValidationError:
return False
def format(number, separator='-', strip_check_digits=False, add_check_digits=True):
"""Reformat the number to the standard presentation format. If
add_check_digits is True the check digit will be added if they are not
present yet. If both strip_check_digits and add_check_digits are True the
check digits will be recalculated."""
(root, episode, check1, version, check2) = split(number)
if strip_check_digits:
check1 = check2 = ''
if add_check_digits and not check1:
check1 = mod_37_36.calc_check_digit(root + episode)
if add_check_digits and not check2 and version:
check2 = mod_37_36.calc_check_digit(root + episode + version)
number = [root[i:i + 4] for i in range(0, 12, 4)] + [episode]
if check1:
number.append(check1)
if version:
number.extend((version[0:4], version[4:]))
if check2:
number.append(check2)
return separator.join(number)
def to_binary(number):
"""Convert the number to its binary representation (without the check
digits)."""
from binascii import a2b_hex
return a2b_hex(compact(number, strip_check_digits=True))
def to_xml(number):
"""Return the XML form of the ISAN as a string."""
number = format(number, strip_check_digits=True, add_check_digits=False)
return '<ISAN root="%s" episode="%s" version="%s" />' % (
number[0:14], number[15:19], number[20:])
def to_urn(number):
"""Return the URN representation of the ISAN."""
return 'URN:ISAN:' + format(number, add_check_digits=True)
|