diff options
Diffstat (limited to 'lib/crc64.c')
| -rw-r--r-- | lib/crc64.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/lib/crc64.c b/lib/crc64.c index 0ef8ae6ac047..61ae8dfb6a1c 100644 --- a/lib/crc64.c +++ b/lib/crc64.c @@ -4,7 +4,7 @@ * * This is a basic crc64 implementation following ECMA-182 specification, * which can be found from, - * http://www.ecma-international.org/publications/standards/Ecma-182.htm + * 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 @@ -22,12 +22,20 @@ * 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"); @@ -36,7 +44,7 @@ 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. + * or the previous crc64 value if computing incrementally. * @p: pointer to buffer over which CRC64 is run * @len: length of buffer @p */ @@ -54,3 +62,24 @@ u64 __pure crc64_be(u64 crc, const void *p, size_t len) 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); |