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- #-----------------------------------------------------------------------------
- # Low level CRC functions for use by crcmod. This version is implemented in
- # Python for a couple of reasons. 1) Provide a reference implememtation.
- # 2) Provide a version that can be used on systems where a C compiler is not
- # available for building extension modules.
- #
- # Copyright (c) 2004 Raymond L. Buvel
- #
- # 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.
- #-----------------------------------------------------------------------------
- def _crc8(data, crc, table):
- crc = crc & 0xFF
- for x in data:
- crc = table[ord(x) ^ crc]
- return crc
- def _crc8r(data, crc, table):
- crc = crc & 0xFF
- for x in data:
- crc = table[ord(x) ^ crc]
- return crc
- def _crc16(data, crc, table):
- crc = crc & 0xFFFF
- for x in data:
- crc = table[ord(x) ^ ((crc>>8) & 0xFF)] ^ ((crc << 8) & 0xFF00)
- return crc
- def _crc16r(data, crc, table):
- crc = crc & 0xFFFF
- for x in data:
- crc = table[ord(x) ^ (crc & 0xFF)] ^ (crc >> 8)
- return crc
- def _crc24(data, crc, table):
- crc = crc & 0xFFFFFF
- for x in data:
- crc = table[ord(x) ^ (int(crc>>16) & 0xFF)] ^ ((crc << 8) & 0xFFFF00)
- return crc
- def _crc24r(data, crc, table):
- crc = crc & 0xFFFFFF
- for x in data:
- crc = table[ord(x) ^ int(crc & 0xFF)] ^ (crc >> 8)
- return crc
- def _crc32(data, crc, table):
- crc = crc & 0xFFFFFFFFL
- for x in data:
- crc = table[ord(x) ^ (int(crc>>24) & 0xFF)] ^ ((crc << 8) & 0xFFFFFF00L)
- return crc
- def _crc32r(data, crc, table):
- crc = crc & 0xFFFFFFFFL
- for x in data:
- crc = table[ord(x) ^ int(crc & 0xFFL)] ^ (crc >> 8)
- return crc
- def _crc64(data, crc, table):
- crc = crc & 0xFFFFFFFFFFFFFFFFL
- for x in data:
- crc = table[ord(x) ^ (int(crc>>56) & 0xFF)] ^ ((crc << 8) & 0xFFFFFFFFFFFFFF00L)
- return crc
- def _crc64r(data, crc, table):
- crc = crc & 0xFFFFFFFFFFFFFFFFL
- for x in data:
- crc = table[ord(x) ^ int(crc & 0xFFL)] ^ (crc >> 8)
- return crc
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