diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /lib/crc64.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/6.1.76.tar.xz linux-upstream/6.1.76.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/crc64.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/lib/crc64.c b/lib/crc64.c new file mode 100644 index 000000000..61ae8dfb6 --- /dev/null +++ b/lib/crc64.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Normal 64-bit CRC calculation. + * + * This is a basic crc64 implementation following ECMA-182 specification, + * which can be found from, + * https://www.ecma-international.org/publications/standards/Ecma-182.htm + * + * Dr. Ross N. Williams has a great document to introduce the idea of CRC + * algorithm, here the CRC64 code is also inspired by the table-driven + * algorithm and detail example from this paper. This paper can be found + * from, + * http://www.ross.net/crc/download/crc_v3.txt + * + * crc64table[256] is the lookup table of a table-driven 64-bit CRC + * calculation, which is generated by gen_crc64table.c in kernel build + * time. The polynomial of crc64 arithmetic is from ECMA-182 specification + * as well, which is defined as, + * + * x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 + + * x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 + + * x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 + + * x^7 + x^4 + x + 1 + * + * crc64rocksoft[256] table is from the Rocksoft specification polynomial + * defined as, + * + * x^64 + x^63 + x^61 + x^59 + x^58 + x^56 + x^55 + x^52 + x^49 + x^48 + x^47 + + * x^46 + x^44 + x^41 + x^37 + x^36 + x^34 + x^32 + x^31 + x^28 + x^26 + x^23 + + * x^22 + x^19 + x^16 + x^13 + x^12 + x^10 + x^9 + x^6 + x^4 + x^3 + 1 + * + * Copyright 2018 SUSE Linux. + * Author: Coly Li <colyli@suse.de> + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/crc64.h> +#include "crc64table.h" + +MODULE_DESCRIPTION("CRC64 calculations"); +MODULE_LICENSE("GPL v2"); + +/** + * crc64_be - Calculate bitwise big-endian ECMA-182 CRC64 + * @crc: seed value for computation. 0 or (u64)~0 for a new CRC calculation, + * or the previous crc64 value if computing incrementally. + * @p: pointer to buffer over which CRC64 is run + * @len: length of buffer @p + */ +u64 __pure crc64_be(u64 crc, const void *p, size_t len) +{ + size_t i, t; + + const unsigned char *_p = p; + + for (i = 0; i < len; i++) { + t = ((crc >> 56) ^ (*_p++)) & 0xFF; + crc = crc64table[t] ^ (crc << 8); + } + + return crc; +} +EXPORT_SYMBOL_GPL(crc64_be); + +/** + * crc64_rocksoft_generic - Calculate bitwise Rocksoft CRC64 + * @crc: seed value for computation. 0 for a new CRC calculation, or the + * previous crc64 value if computing incrementally. + * @p: pointer to buffer over which CRC64 is run + * @len: length of buffer @p + */ +u64 __pure crc64_rocksoft_generic(u64 crc, const void *p, size_t len) +{ + const unsigned char *_p = p; + size_t i; + + crc = ~crc; + + for (i = 0; i < len; i++) + crc = (crc >> 8) ^ crc64rocksofttable[(crc & 0xff) ^ *_p++]; + + return ~crc; +} +EXPORT_SYMBOL_GPL(crc64_rocksoft_generic); |