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/* crc64.c - crc64 function */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2008,2011 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/types.h>
#include <grub/dl.h>
#include <grub/crypto.h>
GRUB_MOD_LICENSE ("GPLv3+");
static grub_uint64_t crc64_table [256];
/* Helper for init_crc64_table. */
static grub_uint64_t
reflect (grub_uint64_t ref, int len)
{
grub_uint64_t result = 0;
int i;
for (i = 1; i <= len; i++)
{
if (ref & 1)
result |= 1ULL << (len - i);
ref >>= 1;
}
return result;
}
static void
init_crc64_table (void)
{
grub_uint64_t polynomial = 0x42f0e1eba9ea3693ULL;
int i, j;
for(i = 0; i < 256; i++)
{
crc64_table[i] = reflect(i, 8) << 56;
for (j = 0; j < 8; j++)
{
crc64_table[i] = (crc64_table[i] << 1) ^
(crc64_table[i] & (1ULL << 63) ? polynomial : 0);
}
crc64_table[i] = reflect(crc64_table[i], 64);
}
}
static void
crc64_init (void *context)
{
if (! crc64_table[1])
init_crc64_table ();
*(grub_uint64_t *) context = 0;
}
static void
crc64_write (void *context, const void *buf, grub_size_t size)
{
unsigned i;
const grub_uint8_t *data = buf;
grub_uint64_t crc = ~grub_le_to_cpu64 (*(grub_uint64_t *) context);
for (i = 0; i < size; i++)
{
crc = (crc >> 8) ^ crc64_table[(crc & 0xFF) ^ *data];
data++;
}
*(grub_uint64_t *) context = grub_cpu_to_le64 (~crc);
}
static grub_uint8_t *
crc64_read (void *context)
{
return context;
}
static void
crc64_final (void *context __attribute__ ((unused)))
{
}
gcry_md_spec_t _gcry_digest_spec_crc64 =
{
"CRC64", 0, 0, 0, 8,
crc64_init, crc64_write, crc64_final, crc64_read,
sizeof (grub_uint64_t),
.blocksize = 64
};
GRUB_MOD_INIT(crc64)
{
grub_md_register (&_gcry_digest_spec_crc64);
}
GRUB_MOD_FINI(crc64)
{
grub_md_unregister (&_gcry_digest_spec_crc64);
}
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