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Shared/lib/python3.4/site-packages/stdnum/isbn.py

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+# isbn.py - functions for handling ISBNs
+#
+# 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
+
+"""ISBN (International Standard Book Number).
+
+The ISBN is the International Standard Book Number, used to identify
+publications. This module supports both numbers in ISBN-10 (10-digit) and
+ISBN-13 (13-digit) format.
+
+>>> validate('978-9024538270')
+'9789024538270'
+>>> validate('978-9024538271')
+Traceback (most recent call last):
+    ...
+InvalidChecksum: ...
+>>> compact('1-85798-218-5')
+'1857982185'
+>>> format('9780471117094')
+'978-0-471-11709-4'
+>>> format('1857982185')
+'1-85798-218-5'
+>>> isbn_type('1-85798-218-5')
+'ISBN10'
+>>> isbn_type('978-0-471-11709-4')
+'ISBN13'
+>>> to_isbn13('1-85798-218-5')
+'978-1-85798-218-3'
+>>> to_isbn10('978-1-85798-218-3')
+'1-85798-218-5'
+"""
+
+from stdnum import ean
+from stdnum.exceptions import *
+from stdnum.util import clean
+
+
+def compact(number, convert=False):
+    """Convert the ISBN to the minimal representation. This strips the number
+    of any valid ISBN separators and removes surrounding whitespace. If the
+    covert parameter is True the number is also converted to ISBN-13
+    format."""
+    number = clean(number, ' -').strip().upper()
+    if len(number) == 9:
+        number = '0' + number
+    if convert:
+        return to_isbn13(number)
+    return number
+
+
+def _calc_isbn10_check_digit(number):
+    """Calculate the ISBN check digit for 10-digit numbers. The number passed
+    should not have the check bit included."""
+    check = sum((i + 1) * int(n)
+                for i, n in enumerate(number)) % 11
+    return 'X' if check == 10 else str(check)
+
+
+def validate(number, convert=False):
+    """Checks to see if the number provided is a valid ISBN (either a legacy
+    10-digit one or a 13-digit one). This checks the length and the check
+    bit but does not check if the group and publisher are valid (use split()
+    for that)."""
+    number = compact(number, convert=False)
+    if not number[:-1].isdigit():
+        raise InvalidFormat()
+    if len(number) == 10:
+        if _calc_isbn10_check_digit(number[:-1]) != number[-1]:
+            raise InvalidChecksum()
+    elif len(number) == 13:
+        ean.validate(number)
+    else:
+        raise InvalidLength()
+    if convert:
+        number = to_isbn13(number)
+    return number
+
+
+def isbn_type(number):
+    """Check the passed number and returns 'ISBN13', 'ISBN10' or None (for
+    invalid) for checking the type of number passed."""
+    try:
+        number = validate(number, convert=False)
+    except ValidationError:
+        return None
+    if len(number) == 10:
+        return 'ISBN10'
+    elif len(number) == 13:
+        return 'ISBN13'
+
+
+def is_valid(number):
+    """Checks to see if the number provided is a valid ISBN (either a legacy
+    10-digit one or a 13-digit one). This checks the length and the check
+    bit but does not check if the group and publisher are valid (use split()
+    for that)."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False
+
+
+def to_isbn13(number):
+    """Convert the number to ISBN-13 format."""
+    number = number.strip()
+    min_number = compact(number, convert=False)
+    if len(min_number) == 13:
+        return number  # nothing to do, already ISBN-13
+    # put new check digit in place
+    number = number[:-1] + ean.calc_check_digit('978' + min_number[:-1])
+    # add prefix
+    if ' ' in number:
+        return '978 ' + number
+    elif '-' in number:
+        return '978-' + number
+    else:
+        return '978' + number
+
+
+def to_isbn10(number):
+    """Convert the number to ISBN-10 format."""
+    number = number.strip()
+    min_number = compact(number, convert=False)
+    if len(min_number) == 10:
+        return number  # nothing to do, already ISBN-13
+    elif isbn_type(min_number) != 'ISBN13':
+        raise InvalidFormat('Not a valid ISBN13.')
+    elif not number.startswith('978'):
+        raise InvalidFormat('Does not use 978 Bookland prefix.')
+    # strip EAN prefix
+    number = number[3:-1].strip().strip('-')
+    digit = _calc_isbn10_check_digit(min_number[3:-1])
+    # append the new check digit
+    if ' ' in number:
+        return number + ' ' + digit
+    elif '-' in number:
+        return number + '-' + digit
+    else:
+        return number + digit
+
+
+def split(number, convert=False):
+    """Split the specified ISBN into an EAN.UCC prefix, a group prefix, a
+    registrant, an item number and a check-digit. If the number is in ISBN-10
+    format the returned EAN.UCC prefix is '978'. If the covert parameter is
+    True the number is converted to ISBN-13 format first."""
+    from stdnum import numdb
+    # clean up number
+    number = compact(number, convert)
+    # get Bookland prefix if any
+    delprefix = False
+    if len(number) == 10:
+        number = '978' + number
+        delprefix = True
+    # split the number
+    result = numdb.get('isbn').split(number[:-1])
+    itemnr = result.pop() if result else ''
+    prefix = result.pop(0) if result else ''
+    group = result.pop(0) if result else ''
+    publisher = result.pop(0) if result else ''
+    # return results
+    return ('' if delprefix else prefix, group, publisher, itemnr, number[-1])
+
+
+def format(number, separator='-', convert=False):
+    """Reformat the passed number to the standard format with the EAN.UCC
+    prefix (if any), the group prefix, the registrant, the item number and
+    the check-digit separated (if possible) by the specified separator.
+    Passing an empty separator should equal compact() though this is less
+    efficient. If the covert parameter is True the number is converted to
+    ISBN-13 format first."""
+    return separator.join(x for x in split(number, convert) if x)