crc.rs

pub fn crc_checksum(data: &[u8]) -> u32 {
    if data.len() == 0 {
        return 0;
    }

    let initial = data
        .iter()
        .take(4)
        .chain([0; 4].iter())
        .take(4)
        .fold(0u32, |acc, byte| (acc << 8) | (*byte as u32));

    let value = data.iter().skip(4).fold(!initial, |value, byte| {
        CRC_TABLE[(value >> 24) as usize] ^ ((*byte as u32) | (value << 8))
    });

    !value
}

pub const CRC_TABLE: [u32; 256] = [
    0, 79764919, 159529838, 222504665, 319059676, 398814059, 445009330, 507990021, 638119352,
    583659535, 797628118, 726387553, 890018660, 835552979, 1015980042, 944750013, 1276238704,
    1221641927, 1167319070, 1095957929, 1595256236, 1540665371, 1452775106, 1381403509, 1780037320,
    1859660671, 1671105958, 1733955601, 2031960084, 2111593891, 1889500026, 1952343757, 2552477408,
    2632100695, 2443283854, 2506133561, 2334638140, 2414271883, 2191915858, 2254759653, 3190512472,
    3135915759, 3081330742, 3009969537, 2905550212, 2850959411, 2762807018, 2691435357, 3560074640,
    3505614887, 3719321342, 3648080713, 3342211916, 3287746299, 3467911202, 3396681109, 4063920168,
    4143685023, 4223187782, 4286162673, 3779000052, 3858754371, 3904687514, 3967668269, 881225847,
    809987520, 1023691545, 969234094, 662832811, 591600412, 771767749, 717299826, 311336399,
    374308984, 453813921, 533576470, 25881363, 88864420, 134795389, 214552010, 2023205639,
    2086057648, 1897238633, 1976864222, 1804852699, 1867694188, 1645340341, 1724971778, 1587496639,
    1516133128, 1461550545, 1406951526, 1302016099, 1230646740, 1142491917, 1087903418, 2896545431,
    2825181984, 2770861561, 2716262478, 3215044683, 3143675388, 3055782693, 3001194130, 2326604591,
    2389456536, 2200899649, 2280525302, 2578013683, 2640855108, 2418763421, 2498394922, 3769900519,
    3832873040, 3912640137, 3992402750, 4088425275, 4151408268, 4197601365, 4277358050, 3334271071,
    3263032808, 3476998961, 3422541446, 3585640067, 3514407732, 3694837229, 3640369242, 1762451694,
    1842216281, 1619975040, 1682949687, 2047383090, 2127137669, 1938468188, 2001449195, 1325665622,
    1271206113, 1183200824, 1111960463, 1543535498, 1489069629, 1434599652, 1363369299, 622672798,
    568075817, 748617968, 677256519, 907627842, 853037301, 1067152940, 995781531, 51762726,
    131386257, 177728840, 240578815, 269590778, 349224269, 429104020, 491947555, 4046411278,
    4126034873, 4172115296, 4234965207, 3794477266, 3874110821, 3953728444, 4016571915, 3609705398,
    3555108353, 3735388376, 3664026991, 3290680682, 3236090077, 3449943556, 3378572211, 3174993278,
    3120533705, 3032266256, 2961025959, 2923101090, 2868635157, 2813903052, 2742672763, 2604032198,
    2683796849, 2461293480, 2524268063, 2284983834, 2364738477, 2175806836, 2238787779, 1569362073,
    1498123566, 1409854455, 1355396672, 1317987909, 1246755826, 1192025387, 1137557660, 2072149281,
    2135122070, 1912620623, 1992383480, 1753615357, 1816598090, 1627664531, 1707420964, 295390185,
    358241886, 404320391, 483945776, 43990325, 106832002, 186451547, 266083308, 932423249,
    861060070, 1041341759, 986742920, 613929101, 542559546, 756411363, 701822548, 3316196985,
    3244833742, 3425377559, 3370778784, 3601682597, 3530312978, 3744426955, 3689838204, 3819031489,
    3881883254, 3928223919, 4007849240, 4037393693, 4100235434, 4180117107, 4259748804, 2310601993,
    2373574846, 2151335527, 2231098320, 2596047829, 2659030626, 2470359227, 2550115596, 2947551409,
    2876312838, 2788305887, 2733848168, 3165939309, 3094707162, 3040238851, 2985771188,
];