116 lines
2.9 KiB
Python
116 lines
2.9 KiB
Python
"""Module: barcode.upc
|
|
|
|
:Provided barcodes: UPC-A
|
|
"""
|
|
__docformat__ = "restructuredtext en"
|
|
|
|
from functools import reduce
|
|
|
|
from barcode.base import Barcode
|
|
from barcode.charsets import upc as _upc
|
|
from barcode.errors import IllegalCharacterError
|
|
from barcode.errors import NumberOfDigitsError
|
|
|
|
|
|
class UniversalProductCodeA(Barcode):
|
|
"""Universal Product Code (UPC) barcode.
|
|
|
|
UPC-A consists of 12 numeric digits.
|
|
"""
|
|
|
|
name = "UPC-A"
|
|
|
|
digits = 11
|
|
|
|
def __init__(self, upc, writer=None, make_ean=False) -> None:
|
|
"""Initializes new UPC-A barcode.
|
|
|
|
:param str upc: The upc number as string.
|
|
:param writer: barcode.writer instance. The writer to render the
|
|
barcode (default: SVGWriter).
|
|
:param bool make_ean: Indicates if a leading zero should be added to
|
|
the barcode. This converts the UPC into a valid European Article
|
|
Number (EAN).
|
|
"""
|
|
self.ean = make_ean
|
|
upc = upc[: self.digits]
|
|
if not upc.isdigit():
|
|
raise IllegalCharacterError("UPC code can only contain numbers.")
|
|
if len(upc) != self.digits:
|
|
raise NumberOfDigitsError(
|
|
f"UPC must have {self.digits} digits, not {len(upc)}."
|
|
)
|
|
self.upc = upc
|
|
self.upc = f"{upc}{self.calculate_checksum()}"
|
|
self.writer = writer or self.default_writer()
|
|
|
|
def __str__(self) -> str:
|
|
if self.ean:
|
|
return "0" + self.upc
|
|
|
|
return self.upc
|
|
|
|
def get_fullcode(self):
|
|
if self.ean:
|
|
return "0" + self.upc
|
|
|
|
return self.upc
|
|
|
|
def calculate_checksum(self):
|
|
"""Calculates the checksum for UPCA/UPC codes
|
|
|
|
:return: The checksum for 'self.upc'
|
|
:rtype: int
|
|
"""
|
|
|
|
def sum_(x, y):
|
|
return int(x) + int(y)
|
|
|
|
upc = self.upc[0 : self.digits]
|
|
oddsum = reduce(sum_, upc[::2])
|
|
evensum = reduce(sum_, upc[1::2])
|
|
check = (evensum + oddsum * 3) % 10
|
|
if check == 0:
|
|
return 0
|
|
|
|
return 10 - check
|
|
|
|
def build(self):
|
|
"""Builds the barcode pattern from 'self.upc'
|
|
|
|
:return: The pattern as string
|
|
:rtype: str
|
|
"""
|
|
code = _upc.EDGE[:]
|
|
|
|
for _i, number in enumerate(self.upc[0:6]):
|
|
code += _upc.CODES["L"][int(number)]
|
|
|
|
code += _upc.MIDDLE
|
|
|
|
for number in self.upc[6:]:
|
|
code += _upc.CODES["R"][int(number)]
|
|
|
|
code += _upc.EDGE
|
|
|
|
return [code]
|
|
|
|
def to_ascii(self):
|
|
"""Returns an ascii representation of the barcode.
|
|
|
|
:rtype: str
|
|
"""
|
|
|
|
code = self.build()
|
|
for i, line in enumerate(code):
|
|
code[i] = line.replace("1", "|").replace("0", "_")
|
|
return "\n".join(code)
|
|
|
|
def render(self, writer_options=None, text=None):
|
|
options = {"module_width": 0.33}
|
|
options.update(writer_options or {})
|
|
return super().render(options, text)
|
|
|
|
|
|
UPCA = UniversalProductCodeA
|