File: //home/arjun/projects/env/lib/python3.10/site-packages/faker/providers/barcode/en_US/__init__.py
import re
from itertools import product
from typing import Dict, Optional, Pattern
from .. import PrefixType
from .. import Provider as BarcodeProvider
class Provider(BarcodeProvider):
"""Implement barcode provider for ``en_US`` locale.
Sources:
- https://gs1.org/standards/id-keys/company-prefix
"""
local_prefixes = (
*product((0,), range(10)),
*product((1,), range(4)),
)
upc_e_base_pattern: Pattern = re.compile(r"^\d{6}$")
upc_ae_pattern1: Pattern = re.compile(
r"^(?P<number_system_digit>[01])" # The first digit must be 0 or 1
r"(?=\d{11}$)" # followed by 11 digits of which
r"(?P<mfr_code>\d{2})" # the first 2 digits make up the manufacturer code,
r"(?:(?P<extra>[012])0{4})" # if immediately followed by 00000, 10000, or 20000,
r"(?P<product_code>\d{3})" # a 3-digit product code,
r"(?P<check_digit>\d)$", # and finally a check digit.
)
upc_ae_pattern2: Pattern = re.compile(
r"^(?P<number_system_digit>[01])" # The first digit must be 0 or 1
r"(?=\d{11}$)" # followed by 11 digits of which
r"(?P<mfr_code>\d{3,4}?)" # the first 3 or 4 digits make up the manufacturer code,
r"(?:0{5})" # if immediately followed by 00000,
r"(?P<product_code>\d{1,2})" # a 2-digit or single digit product code,
r"(?P<check_digit>\d)$", # and finally a check digit.
)
upc_ae_pattern3: Pattern = re.compile(
r"^(?P<number_system_digit>[01])" # The first digit must be 0 or 1
r"(?=\d{11}$)" # followed by 11 digits of which
r"(?P<mfr_code>\d{5})" # the first 5 digits make up the manufacturer code,
r"(?:0{4}(?P<extra>[5-9]))" # if immediately followed by 0000 and a 5, 6, 7, 8, or 9,
r"(?P<check_digit>\d)$", # and finally a check digit.
)
def ean13(self, prefixes: PrefixType = (), leading_zero: Optional[bool] = None) -> str:
"""Generate an EAN-13 barcode.
If ``leading_zero`` is ``True``, the leftmost digit of the barcode will
be set to ``0``. If ``False``, the leftmost digit cannot be ``0``. If
``None`` (default), the leftmost digit can be any digit.
If a value for ``prefixes`` is specified, the result will begin with one
of the sequences in ``prefixes`` and will ignore ``leading_zero``.
This method uses the standard barcode provider's |ean13| under the
hood with the ``prefixes`` argument set to the correct value to attain
the behavior described above.
.. note::
EAN-13 barcode that starts with a zero can be converted to UPC-A
by dropping the leading zero. This may cause problems with readers
that treat all of these code as UPC-A codes and drop the first digit
when reading it.
You can set the argument ``prefixes`` ( or ``leading_zero`` for
convenience) explicitly to avoid or to force the generated barcode to
start with a zero. You can also generate actual UPC-A barcode with
|EnUsBarcodeProvider.upc_a|.
:sample:
:sample: leading_zero=False
:sample: leading_zero=True
:sample: prefixes=('00',)
:sample: prefixes=('45', '49')
"""
if not prefixes:
if leading_zero is True:
prefixes = ((0,),)
elif leading_zero is False:
prefixes = ((self.random_int(1, 9),),)
return super().ean13(prefixes=prefixes)
def _convert_upc_a2e(self, upc_a: str) -> str:
"""Convert a 12-digit UPC-A barcode to its 8-digit UPC-E equivalent.
.. warning::
Not all UPC-A barcodes can be converted.
"""
if not isinstance(upc_a, str):
raise TypeError("`upc_a` is not a string")
m1 = self.upc_ae_pattern1.match(upc_a)
m2 = self.upc_ae_pattern2.match(upc_a)
m3 = self.upc_ae_pattern3.match(upc_a)
if not any([m1, m2, m3]):
raise ValueError("`upc_a` has an invalid value")
upc_e_template = "{number_system_digit}{mfr_code}{product_code}{extra}{check_digit}"
if m1:
upc_e = upc_e_template.format(**m1.groupdict())
elif m2:
groupdict: Dict[str, str] = m2.groupdict()
mfr_code = groupdict.get("mfr_code") or ""
groupdict["extra"] = str(len(mfr_code))
upc_e = upc_e_template.format(**groupdict)
elif m3:
groupdict = m3.groupdict()
groupdict["product_code"] = ""
upc_e = upc_e_template.format(**groupdict)
return upc_e
def _upc_ae(self, base: Optional[str] = None, number_system_digit: Optional[int] = None) -> str:
"""Create a 12-digit UPC-A barcode that can be converted to UPC-E.
The expected value of ``base`` is a 6-digit string. If any other value
is provided, this method will use a random 6-digit string instead.
The expected value of ``number_system_digit`` is the integer ``0`` or
``1``. If any other value is provided, this method will randomly choose
from the two.
Please also view notes on |EnUsBarcodeProvider.upc_a| and
|EnUsBarcodeProvider.upc_e| for more details.
"""
base_ = (
[int(x) for x in base]
if isinstance(base, str) and self.upc_e_base_pattern.match(base)
else [self.random_int(0, 9) for _ in range(6)]
)
if number_system_digit not in [0, 1]:
number_system_digit = self.random_int(0, 1)
if base_[-1] <= 2:
code = base_[:2] + base_[-1:] + [0] * 4 + base_[2:-1]
elif base_[-1] <= 4:
code = base_[: base_[-1]] + [0] * 5 + base_[base_[-1] : -1]
else:
code = base_[:5] + [0] * 4 + base_[-1:]
code.insert(0, number_system_digit)
weights = [3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3]
weighted_sum = sum(x * y for x, y in zip(code, weights))
check_digit = (10 - weighted_sum % 10) % 10
code.append(check_digit)
return "".join(str(x) for x in code)
def upc_a(
self,
upc_ae_mode: bool = False,
base: Optional[str] = None,
number_system_digit: Optional[int] = None,
) -> str:
"""Generate a 12-digit UPC-A barcode.
The value of ``upc_ae_mode`` controls how barcodes will be generated. If
``False`` (default), barcodes are not guaranteed to have a UPC-E
equivalent. In this mode, the method uses |EnUsBarcodeProvider.ean13|
under the hood, and the values of ``base`` and ``number_system_digit``
will be ignored.
If ``upc_ae_mode`` is ``True``, the resulting barcodes are guaranteed to
have a UPC-E equivalent, and the values of ``base`` and
``number_system_digit`` will be used to control what is generated.
Under this mode, ``base`` is expected to have a 6-digit string value. If
any other value is supplied, a random 6-digit string will be used
instead. As for ``number_system_digit``, the expected value is a ``0``
or a ``1``. If any other value is provided, this method will randomly
choose from the two.
.. important::
When ``upc_ae_mode`` is enabled, you might encounter instances where
different values of ``base`` (e.g. ``'120003'`` and ``'120004'``)
produce the same UPC-A barcode. This is normal, and the reason lies
within the whole conversion process. To learn more about this and
what ``base`` and ``number_system_digit`` actually represent, please
refer to |EnUsBarcodeProvider.upc_e|.
:sample:
:sample: upc_ae_mode=True, number_system_digit=0
:sample: upc_ae_mode=True, number_system_digit=1
:sample: upc_ae_mode=True, base='123456', number_system_digit=0
:sample: upc_ae_mode=True, base='120003', number_system_digit=0
:sample: upc_ae_mode=True, base='120004', number_system_digit=0
"""
if upc_ae_mode is True:
return self._upc_ae(base=base, number_system_digit=number_system_digit)
else:
ean13 = self.ean13(leading_zero=True)
return ean13[1:]
def upc_e(
self,
base: Optional[str] = None,
number_system_digit: Optional[int] = None,
safe_mode: bool = True,
) -> str:
"""Generate an 8-digit UPC-E barcode.
UPC-E barcodes can be expressed in 6, 7, or 8-digit formats, but this
method uses the 8 digit format, since it is trivial to convert to the
other two formats. The first digit (starting from the left) is
controlled by ``number_system_digit``, and it can only be a ``0`` or a
``1``. The last digit is the check digit that is inherited from the
UPC-E barcode's UPC-A equivalent. The middle six digits are collectively
referred to as the ``base`` (for a lack of a better term).
On that note, this method uses ``base`` and ``number_system_digit`` to
first generate a UPC-A barcode for the check digit, and what happens
next depends on the value of ``safe_mode``. The argument ``safe_mode``
exists, because there are some UPC-E values that share the same UPC-A
equivalent. For example, any UPC-E barcode of the form ``abc0000d``,
``abc0003d``, and ``abc0004d`` share the same UPC-A value
``abc00000000d``, but that UPC-A value will only convert to ``abc0000d``
because of (a) how UPC-E is just a zero-suppressed version of UPC-A and
(b) the rules around the conversion.
If ``safe_mode`` is ``True`` (default), this method performs another set
of conversions to guarantee that the UPC-E barcodes generated can be
converted to UPC-A, and that UPC-A barcode can be converted back to the
original UPC-E barcode. Using the example above, even if the bases
``120003`` or ``120004`` are used, the resulting UPC-E barcode will
always use the base ``120000``.
If ``safe_mode`` is ``False``, then the ``number_system_digit``,
``base``, and the computed check digit will just be concatenated
together to produce the UPC-E barcode, and attempting to convert the
barcode to UPC-A and back again to UPC-E will exhibit the behavior
described above.
:sample:
:sample: base='123456'
:sample: base='123456', number_system_digit=0
:sample: base='123456', number_system_digit=1
:sample: base='120000', number_system_digit=0
:sample: base='120003', number_system_digit=0
:sample: base='120004', number_system_digit=0
:sample: base='120000', number_system_digit=0, safe_mode=False
:sample: base='120003', number_system_digit=0, safe_mode=False
:sample: base='120004', number_system_digit=0, safe_mode=False
"""
if safe_mode is not False:
upc_ae = self._upc_ae(base=base, number_system_digit=number_system_digit)
return self._convert_upc_a2e(upc_ae)
else:
upc_ae = self._upc_ae(base=base, number_system_digit=number_system_digit)
return upc_ae[0] + "".join(str(x) for x in base or "") + upc_ae[-1]