/usr/share/pyshared/crcmod/predefined.py is in python-crcmod 1.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 | #-----------------------------------------------------------------------------
# Copyright (c) 2010 Craig McQueen
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#-----------------------------------------------------------------------------
'''
crcmod.predefined defines some well-known CRC algorithms.
To use it, e.g.:
import crcmod.predefined
crc32func = crcmod.predefined.mkPredefinedCrcFun("crc-32")
crc32class = crcmod.predefined.PredefinedCrc("crc-32")
crcmod.predefined.Crc is an alias for crcmod.predefined.PredefinedCrc
But if doing 'from crc.predefined import *', only PredefinedCrc is imported.
'''
# local imports
import crcmod
__all__ = [
'PredefinedCrc',
'mkPredefinedCrcFun',
]
REVERSE = True
NON_REVERSE = False
# The following table defines the parameters of well-known CRC algorithms.
# The "Check" value is the CRC for the ASCII byte sequence "123456789". It
# can be used for unit tests.
_crc_definitions_table = [
# Name Identifier-name, Poly Reverse Init-value XOR-out Check
[ 'crc-8', 'Crc8', 0x107, NON_REVERSE, 0x00, 0x00, 0xF4, ],
[ 'crc-8-darc', 'Crc8Darc', 0x139, REVERSE, 0x00, 0x00, 0x15, ],
[ 'crc-8-i-code', 'Crc8ICode', 0x11D, NON_REVERSE, 0xFD, 0x00, 0x7E, ],
[ 'crc-8-itu', 'Crc8Itu', 0x107, NON_REVERSE, 0x55, 0x55, 0xA1, ],
[ 'crc-8-maxim', 'Crc8Maxim', 0x131, REVERSE, 0x00, 0x00, 0xA1, ],
[ 'crc-8-rohc', 'Crc8Rohc', 0x107, REVERSE, 0xFF, 0x00, 0xD0, ],
[ 'crc-8-wcdma', 'Crc8Wcdma', 0x19B, REVERSE, 0x00, 0x00, 0x25, ],
[ 'crc-16', 'Crc16', 0x18005, REVERSE, 0x0000, 0x0000, 0xBB3D, ],
[ 'crc-16-buypass', 'Crc16Buypass', 0x18005, NON_REVERSE, 0x0000, 0x0000, 0xFEE8, ],
[ 'crc-16-dds-110', 'Crc16Dds110', 0x18005, NON_REVERSE, 0x800D, 0x0000, 0x9ECF, ],
[ 'crc-16-dect', 'Crc16Dect', 0x10589, NON_REVERSE, 0x0001, 0x0001, 0x007E, ],
[ 'crc-16-dnp', 'Crc16Dnp', 0x13D65, REVERSE, 0xFFFF, 0xFFFF, 0xEA82, ],
[ 'crc-16-en-13757', 'Crc16En13757', 0x13D65, NON_REVERSE, 0xFFFF, 0xFFFF, 0xC2B7, ],
[ 'crc-16-genibus', 'Crc16Genibus', 0x11021, NON_REVERSE, 0x0000, 0xFFFF, 0xD64E, ],
[ 'crc-16-maxim', 'Crc16Maxim', 0x18005, REVERSE, 0xFFFF, 0xFFFF, 0x44C2, ],
[ 'crc-16-mcrf4xx', 'Crc16Mcrf4xx', 0x11021, REVERSE, 0xFFFF, 0x0000, 0x6F91, ],
[ 'crc-16-riello', 'Crc16Riello', 0x11021, REVERSE, 0x554D, 0x0000, 0x63D0, ],
[ 'crc-16-t10-dif', 'Crc16T10Dif', 0x18BB7, NON_REVERSE, 0x0000, 0x0000, 0xD0DB, ],
[ 'crc-16-teledisk', 'Crc16Teledisk', 0x1A097, NON_REVERSE, 0x0000, 0x0000, 0x0FB3, ],
[ 'crc-16-usb', 'Crc16Usb', 0x18005, REVERSE, 0x0000, 0xFFFF, 0xB4C8, ],
[ 'x-25', 'CrcX25', 0x11021, REVERSE, 0x0000, 0xFFFF, 0x906E, ],
[ 'xmodem', 'CrcXmodem', 0x11021, NON_REVERSE, 0x0000, 0x0000, 0x31C3, ],
[ 'modbus', 'CrcModbus', 0x18005, REVERSE, 0xFFFF, 0x0000, 0x4B37, ],
# Note definitions of CCITT are disputable. See:
# http://homepages.tesco.net/~rainstorm/crc-catalogue.htm
# http://web.archive.org/web/20071229021252/http://www.joegeluso.com/software/articles/ccitt.htm
[ 'kermit', 'CrcKermit', 0x11021, REVERSE, 0x0000, 0x0000, 0x2189, ],
[ 'crc-ccitt-false', 'CrcCcittFalse', 0x11021, NON_REVERSE, 0xFFFF, 0x0000, 0x29B1, ],
[ 'crc-aug-ccitt', 'CrcAugCcitt', 0x11021, NON_REVERSE, 0x1D0F, 0x0000, 0xE5CC, ],
[ 'crc-24', 'Crc24', 0x1864CFB, NON_REVERSE, 0xB704CE, 0x000000, 0x21CF02, ],
[ 'crc-24-flexray-a', 'Crc24FlexrayA', 0x15D6DCB, NON_REVERSE, 0xFEDCBA, 0x000000, 0x7979BD, ],
[ 'crc-24-flexray-b', 'Crc24FlexrayB', 0x15D6DCB, NON_REVERSE, 0xABCDEF, 0x000000, 0x1F23B8, ],
[ 'crc-32', 'Crc32', 0x104C11DB7, REVERSE, 0x00000000, 0xFFFFFFFF, 0xCBF43926, ],
[ 'crc-32-bzip2', 'Crc32Bzip2', 0x104C11DB7, NON_REVERSE, 0x00000000, 0xFFFFFFFF, 0xFC891918, ],
[ 'crc-32c', 'Crc32C', 0x11EDC6F41, REVERSE, 0x00000000, 0xFFFFFFFF, 0xE3069283, ],
[ 'crc-32d', 'Crc32D', 0x1A833982B, REVERSE, 0x00000000, 0xFFFFFFFF, 0x87315576, ],
[ 'crc-32-mpeg', 'Crc32Mpeg', 0x104C11DB7, NON_REVERSE, 0xFFFFFFFF, 0x00000000, 0x0376E6E7, ],
[ 'posix', 'CrcPosix', 0x104C11DB7, NON_REVERSE, 0xFFFFFFFF, 0xFFFFFFFF, 0x765E7680, ],
[ 'crc-32q', 'Crc32Q', 0x1814141AB, NON_REVERSE, 0x00000000, 0x00000000, 0x3010BF7F, ],
[ 'jamcrc', 'CrcJamCrc', 0x104C11DB7, REVERSE, 0xFFFFFFFF, 0x00000000, 0x340BC6D9, ],
[ 'xfer', 'CrcXfer', 0x1000000AF, NON_REVERSE, 0x00000000, 0x00000000, 0xBD0BE338, ],
# 64-bit
# Name Identifier-name, Poly Reverse Init-value XOR-out Check
[ 'crc-64', 'Crc64', 0x1000000000000001B, REVERSE, 0x0000000000000000, 0x0000000000000000, 0x46A5A9388A5BEFFE, ],
[ 'crc-64-we', 'Crc64We', 0x142F0E1EBA9EA3693, NON_REVERSE, 0x0000000000000000, 0xFFFFFFFFFFFFFFFF, 0x62EC59E3F1A4F00A, ],
[ 'crc-64-jones', 'Crc64Jones', 0x1AD93D23594C935A9, REVERSE, 0xFFFFFFFFFFFFFFFF, 0x0000000000000000, 0xCAA717168609F281, ],
]
def _simplify_name(name):
"""
Reduce CRC definition name to a simplified form:
* lowercase
* dashes removed
* spaces removed
* any initial "CRC" string removed
"""
name = name.lower()
name = name.replace('-', '')
name = name.replace(' ', '')
if name.startswith('crc'):
name = name[len('crc'):]
return name
_crc_definitions_by_name = {}
_crc_definitions_by_identifier = {}
_crc_definitions = []
_crc_table_headings = [ 'name', 'identifier', 'poly', 'reverse', 'init', 'xor_out', 'check' ]
for table_entry in _crc_definitions_table:
crc_definition = dict(zip(_crc_table_headings, table_entry))
_crc_definitions.append(crc_definition)
name = _simplify_name(table_entry[0])
if name in _crc_definitions_by_name:
raise Exception("Duplicate entry for '%s' in CRC table" % name)
_crc_definitions_by_name[name] = crc_definition
_crc_definitions_by_identifier[table_entry[1]] = crc_definition
def _get_definition_by_name(crc_name):
definition = _crc_definitions_by_name.get(_simplify_name(crc_name), None)
if not definition:
definition = _crc_definitions_by_identifier.get(crc_name, None)
if not definition:
raise KeyError("Unkown CRC name '%s'" % crc_name)
return definition
class PredefinedCrc(crcmod.Crc):
def __init__(self, crc_name):
definition = _get_definition_by_name(crc_name)
crcmod.Crc.__init__(self, poly=definition['poly'], initCrc=definition['init'], rev=definition['reverse'], xorOut=definition['xor_out'])
# crcmod.predefined.Crc is an alias for crcmod.predefined.PredefinedCrc
Crc = PredefinedCrc
def mkPredefinedCrcFun(crc_name):
definition = _get_definition_by_name(crc_name)
return crcmod.mkCrcFun(poly=definition['poly'], initCrc=definition['init'], rev=definition['reverse'], xorOut=definition['xor_out'])
# crcmod.predefined.mkCrcFun is an alias for crcmod.predefined.mkPredefinedCrcFun
mkCrcFun = mkPredefinedCrcFun
|