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|
(* LVM uses CRC to verify data *)
let initial_crc = 0xf597a6cfl
let crctab = [|
0x00000000l; 0x1db71064l; 0x3b6e20c8l; 0x26d930acl;
0x76dc4190l; 0x6b6b51f4l; 0x4db26158l; 0x5005713cl;
0xedb88320l; 0xf00f9344l; 0xd6d6a3e8l; 0xcb61b38cl;
0x9b64c2b0l; 0x86d3d2d4l; 0xa00ae278l; 0xbdbdf21cl;
|]
let crc buf init =
let (>>) a b = Int32.shift_right_logical a b in
let (^^) a b = Int32.logxor a b in
let (&&&) a b = Int32.to_int (Int32.logand a b) in
let size = String.length buf in
let rec loop i cur =
if i=size then cur else
let a1 = cur ^^ (Int32.of_int (int_of_char buf.[i])) in
let a2 = (a1 >> 4) ^^ crctab.( a1 &&& 0xfl ) in
let a3 = (a2 >> 4) ^^ crctab.( a2 &&& 0xfl ) in
loop (i+1) a3
in
loop 0 init
|
