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code.delx.au - refind/blob - filesystems/crc32c.c
2 * this file take from grub 2.0
3 * for btrfs UEFI driver
6 static uint32_t crc32c_table
[256];
9 init_crc32c_table (void)
11 auto uint32_t reflect (uint32_t ref
, int len
);
12 uint32_t reflect (uint32_t ref
, int len
)
17 for (i
= 1; i
<= len
; i
++)
20 result
|= 1 << (len
- i
);
27 static int crc32c_table_inited
;
28 if(crc32c_table_inited
)
30 crc32c_table_inited
= 1;
32 uint32_t polynomial
= 0x1edc6f41;
35 for(i
= 0; i
< 256; i
++)
37 crc32c_table
[i
] = reflect(i
, 8) << 24;
38 for (j
= 0; j
< 8; j
++)
39 crc32c_table
[i
] = (crc32c_table
[i
] << 1) ^
40 (crc32c_table
[i
] & (1 << 31) ? polynomial
: 0);
41 crc32c_table
[i
] = reflect(crc32c_table
[i
], 32);
46 grub_getcrc32c (uint32_t crc
, const void *buf
, int size
)
49 const uint8_t *data
= buf
;
51 if (! crc32c_table
[1])
56 for (i
= 0; i
< size
; i
++)
58 crc
= (crc
>> 8) ^ crc32c_table
[(crc
& 0xFF) ^ *data
];
62 return crc
^ 0xffffffff;