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- # -*- coding: utf-8 -*-
- # Part of Odoo. See LICENSE file for full copyright and licensing details.
- import re
-
-
- __all__ = ['check_barcode_encoding']
-
-
- def get_barcode_check_digit(numeric_barcode):
- """ Computes and returns the barcode check digit. The used algorithm
- follows the GTIN specifications and can be used by all compatible
- barcode nomenclature, like as EAN-8, EAN-12 (UPC-A) or EAN-13.
- https://www.gs1.org/sites/default/files/docs/barcodes/GS1_General_Specifications.pdf
- https://www.gs1.org/services/how-calculate-check-digit-manually
- :param numeric_barcode: the barcode to verify/recompute the check digit
- :type numeric_barcode: str
- :return: the number corresponding to the right check digit
- :rtype: int
- """
- # Multiply value of each position by
- # N1 N2 N3 N4 N5 N6 N7 N8 N9 N10 N11 N12 N13 N14 N15 N16 N17 N18
- # x3 X1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 x1 x3 CHECKSUM
- oddsum = evensum = 0
- code = numeric_barcode[-2::-1] # Remove the check digit and reverse the barcode.
- # The CHECKSUM digit is removed because it will be recomputed and it must not interfer with
- # the computation. Also, the barcode is inverted, so the barcode length doesn't matter.
- # Otherwise, the digits' group (even or odd) could be different according to the barcode length.
- for i, digit in enumerate(code):
- if i % 2 == 0:
- evensum += int(digit)
- else:
- oddsum += int(digit)
- total = evensum * 3 + oddsum
- return (10 - total % 10) % 10
-
-
- def check_barcode_encoding(barcode, encoding):
- """ Checks if the given barcode is correctly encoded.
- :return: True if the barcode string is encoded with the provided encoding.
- :rtype: bool
- """
- encoding = encoding.lower()
- if encoding == "any":
- return True
- barcode_sizes = {
- 'ean8': 8,
- 'ean13': 13,
- 'gtin14': 14,
- 'upca': 12,
- 'sscc': 18,
- }
- barcode_size = barcode_sizes[encoding]
- return (encoding != 'ean13' or barcode[0] != '0') \
- and len(barcode) == barcode_size \
- and re.match(r"^\d+$", barcode) \
- and get_barcode_check_digit(barcode) == int(barcode[-1])
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