From 85d8bf57131a21424b50e50884372e813345f09a Mon Sep 17 00:00:00 2001 From: Marek Behún Date: Sun, 3 Sep 2017 17:00:23 +0200 Subject: lib: Add CRC32-C This is needed for BTRFS. Signed-off-by: Marek Behun create mode 100644 lib/crc32c.c --- lib/crc32c.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 lib/crc32c.c (limited to 'lib/crc32c.c') diff --git a/lib/crc32c.c b/lib/crc32c.c new file mode 100644 index 0000000000..322c08ff5d --- /dev/null +++ b/lib/crc32c.c @@ -0,0 +1,38 @@ +/* + * Copied from Linux kernel crypto/crc32c.c + * Copyright (c) 2004 Cisco Systems, Inc. + * Copyright (c) 2008 Herbert Xu + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include +#include + +uint32_t crc32c_cal(uint32_t crc, const char *data, int length, + uint32_t *crc32c_table) +{ + while (length--) + crc = crc32c_table[(u8)(crc ^ *data++)] ^ (crc >> 8); + + return crc; +} + +void crc32c_init(uint32_t *crc32c_table, uint32_t pol) +{ + int i, j; + uint32_t v; + const uint32_t poly = pol; /* Bit-reflected CRC32C polynomial */ + + for (i = 0; i < 256; i++) { + v = i; + for (j = 0; j < 8; j++) + v = (v >> 1) ^ ((v & 1) ? poly : 0); + + crc32c_table[i] = v; + } +} -- cgit v1.2.3