rs1090 0.5.2

Rust library to decode Mode S and ADS-B signals
Documentation 
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use deku::prelude::*;

/// For performance concerns, the CRC_TABLE is statically computed
#[rustfmt::skip]
pub const CRC_TABLE: [u32; 256] = [
    0x0000_0000, 0x00ff_f409, 0x0000_1c1b, 0x00ff_e812, 0x0000_3836, 0x00ff_cc3f,
    0x0000_242d, 0x00ff_d024, 0x0000_706c, 0x00ff_8465, 0x0000_6c77, 0x00ff_987e,
    0x0000_485a, 0x00ff_bc53, 0x0000_5441, 0x00ff_a048, 0x0000_e0d8, 0x00ff_14d1,
    0x0000_fcc3, 0x00ff_08ca, 0x0000_d8ee, 0x00ff_2ce7, 0x0000_c4f5, 0x00ff_30fc,
    0x0000_90b4, 0x00ff_64bd, 0x0000_8caf, 0x00ff_78a6, 0x0000_a882, 0x00ff_5c8b,
    0x0000_b499, 0x00ff_4090, 0x0001_c1b0, 0x00fe_35b9, 0x0001_ddab, 0x00fe_29a2,
    0x0001_f986, 0x00fe_0d8f, 0x0001_e59d, 0x00fe_1194, 0x0001_b1dc, 0x00fe_45d5,
    0x0001_adc7, 0x00fe_59ce, 0x0001_89ea, 0x00fe_7de3, 0x0001_95f1, 0x00fe_61f8,
    0x0001_2168, 0x00fe_d561, 0x0001_3d73, 0x00fe_c97a, 0x0001_195e, 0x00fe_ed57,
    0x0001_0545, 0x00fe_f14c, 0x0001_5104, 0x00fe_a50d, 0x0001_4d1f, 0x00fe_b916,
    0x0001_6932, 0x00fe_9d3b, 0x0001_7529, 0x00fe_8120, 0x0003_8360, 0x00fc_7769,
    0x0003_9f7b, 0x00fc_6b72, 0x0003_bb56, 0x00fc_4f5f, 0x0003_a74d, 0x00fc_5344,
    0x0003_f30c, 0x00fc_0705, 0x0003_ef17, 0x00fc_1b1e, 0x0003_cb3a, 0x00fc_3f33,
    0x0003_d721, 0x00fc_2328, 0x0003_63b8, 0x00fc_97b1, 0x0003_7fa3, 0x00fc_8baa,
    0x0003_5b8e, 0x00fc_af87, 0x0003_4795, 0x00fc_b39c, 0x0003_13d4, 0x00fc_e7dd,
    0x0003_0fcf, 0x00fc_fbc6, 0x0003_2be2, 0x00fc_dfeb, 0x0003_37f9, 0x00fc_c3f0,
    0x0002_42d0, 0x00fd_b6d9, 0x0002_5ecb, 0x00fd_aac2, 0x0002_7ae6, 0x00fd_8eef,
    0x0002_66fd, 0x00fd_92f4, 0x0002_32bc, 0x00fd_c6b5, 0x0002_2ea7, 0x00fd_daae,
    0x0002_0a8a, 0x00fd_fe83, 0x0002_1691, 0x00fd_e298, 0x0002_a208, 0x00fd_5601,
    0x0002_be13, 0x00fd_4a1a, 0x0002_9a3e, 0x00fd_6e37, 0x0002_8625, 0x00fd_722c,
    0x0002_d264, 0x00fd_266d, 0x0002_ce7f, 0x00fd_3a76, 0x0002_ea52, 0x00fd_1e5b,
    0x0002_f649, 0x00fd_0240, 0x0007_06c0, 0x00f8_f2c9, 0x0007_1adb, 0x00f8_eed2,
    0x0007_3ef6, 0x00f8_caff, 0x0007_22ed, 0x00f8_d6e4, 0x0007_76ac, 0x00f8_82a5,
    0x0007_6ab7, 0x00f8_9ebe, 0x0007_4e9a, 0x00f8_ba93, 0x0007_5281, 0x00f8_a688,
    0x0007_e618, 0x00f8_1211, 0x0007_fa03, 0x00f8_0e0a, 0x0007_de2e, 0x00f8_2a27,
    0x0007_c235, 0x00f8_363c, 0x0007_9674, 0x00f8_627d, 0x0007_8a6f, 0x00f8_7e66,
    0x0007_ae42, 0x00f8_5a4b, 0x0007_b259, 0x00f8_4650, 0x0006_c770, 0x00f9_3379,
    0x0006_db6b, 0x00f9_2f62, 0x0006_ff46, 0x00f9_0b4f, 0x0006_e35d, 0x00f9_1754,
    0x0006_b71c, 0x00f9_4315, 0x0006_ab07, 0x00f9_5f0e, 0x0006_8f2a, 0x00f9_7b23,
    0x0006_9331, 0x00f9_6738, 0x0006_27a8, 0x00f9_d3a1, 0x0006_3bb3, 0x00f9_cfba,
    0x0006_1f9e, 0x00f9_eb97, 0x0006_0385, 0x00f9_f78c, 0x0006_57c4, 0x00f9_a3cd,
    0x0006_4bdf, 0x00f9_bfd6, 0x0006_6ff2, 0x00f9_9bfb, 0x0006_73e9, 0x00f9_87e0,
    0x0004_85a0, 0x00fb_71a9, 0x0004_99bb, 0x00fb_6db2, 0x0004_bd96, 0x00fb_499f,
    0x0004_a18d, 0x00fb_5584, 0x0004_f5cc, 0x00fb_01c5, 0x0004_e9d7, 0x00fb_1dde,
    0x0004_cdfa, 0x00fb_39f3, 0x0004_d1e1, 0x00fb_25e8, 0x0004_6578, 0x00fb_9171,
    0x0004_7963, 0x00fb_8d6a, 0x0004_5d4e, 0x00fb_a947, 0x0004_4155, 0x00fb_b55c,
    0x0004_1514, 0x00fb_e11d, 0x0004_090f, 0x00fb_fd06, 0x0004_2d22, 0x00fb_d92b,
    0x0004_3139, 0x00fb_c530, 0x0005_4410, 0x00fa_b019, 0x0005_580b, 0x00fa_ac02,
    0x0005_7c26, 0x00fa_882f, 0x0005_603d, 0x00fa_9434, 0x0005_347c, 0x00fa_c075,
    0x0005_2867, 0x00fa_dc6e, 0x0005_0c4a, 0x00fa_f843, 0x0005_1051, 0x00fa_e458,
    0x0005_a4c8, 0x00fa_50c1, 0x0005_b8d3, 0x00fa_4cda, 0x0005_9cfe, 0x00fa_68f7,
    0x0005_80e5, 0x00fa_74ec, 0x0005_d4a4, 0x00fa_20ad, 0x0005_c8bf, 0x00fa_3cb6,
    0x0005_ec92, 0x00fa_189b, 0x0005_f089, 0x00fa_0480,
];

/// Compute the checksum of the given message
///
/// This should be equal to 0 for ADS-B messages.
pub fn modes_checksum(message: &[u8], bits: usize) -> Result<u32, DekuError> {
    let mut rem: u32 = 0;
    let n = bits / 8;

    if (n < 3) || (message.len() < n) {
        return Err(DekuError::Incomplete(NeedSize::new(4)));
    }

    for i in 0..(n - 3) {
        rem = (rem << 8)
            ^ CRC_TABLE[(u32::from(message[i]) ^ ((rem & 0x00ff_0000) >> 16))
                as usize];
        rem &= 0x00ff_ffff;
    }

    let msg_1 = u32::from(message[n - 3]) << 16;
    let msg_2 = u32::from(message[n - 2]) << 8;
    let msg_3 = u32::from(message[n - 1]);
    let xor_term: u32 = msg_1 ^ msg_2 ^ msg_3;

    rem ^= xor_term;

    Ok(rem)
}

#[cfg(test)]
mod tests {
    use super::*;
    use hexlit::hex;

    #[test]
    fn test_crc() {
        let bytes = hex!("8D406B902015A678D4D220AA4BDA");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d8960ed58bf053cf11bc5932b7d");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d45cab390c39509496ca9a32912");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d49d3d4e1089d00000000744c3b");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d74802958c904e6ef4ba0184d5c");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d4400cd9b0000b4f87000e71a10");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);
        let bytes = hex!("8d4065de58a1054a7ef0218e226a");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 0);

        let bytes = hex!("c80b2dca34aa21dd821a04cb64d4");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 10719924);
        let bytes = hex!("a800089d8094e33a6004e4b8a522");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 4805588);
        let bytes = hex!("a8000614a50b6d32bed000bbe0ed");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 5659991);
        let bytes = hex!("a0000410bc900010a40000f5f477");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 11727682);
        let bytes = hex!("8d4ca251204994b1c36e60a5343d");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 16);
        let bytes = hex!("b0001718c65632b0a82040715b65");
        let crc = modes_checksum(&bytes, 14 * 8).unwrap();
        assert_eq!(crc, 353333);
    }
}