1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103

// Note that this isn't really intended to be a user-facing crate, that's
// `flate2::Crc`

#[macro_use]
extern crate cfg_if;

#[cfg(test)]
#[macro_use]
extern crate quickcheck;

cfg_if! {
    if #[cfg(not(simd))] {
        mod other;
        use self::other as imp;
    } else if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
        mod x86;
        use self::x86 as imp;
    } else {
        mod other;
        use self::other as imp;
    }
}

#[derive(Debug)]
pub struct Hardware(bool);

impl Hardware {
    #[inline]
    pub fn detect() -> Hardware {
        Hardware(imp::detect())
    }

    #[inline]
    pub fn calculate(
        &self,
        crc: u32,
        data: &[u8],
        fallback: fn(u32, &[u8]) -> u32,
    ) -> u32 {
        if self.0 {
            unsafe { imp::calculate(crc, data, fallback) }
        } else {
            fallback(crc, data)
        }
    }
}

#[cfg(test)]
mod tests {
    extern crate miniz_sys;
    extern crate rand;
    extern crate rayon;

    use self::rand::Rng;
    use self::rayon::prelude::*;
    use super::Hardware;

    fn fallback(a: u32, b: &[u8]) -> u32 {
        unsafe {
            miniz_sys::mz_crc32(a as _, b.as_ptr(), b.len()) as u32
        }
    }

    fn random_chunks(iters: usize, lo: usize, hi: usize) {
        let hardware = Hardware::detect();

        (0..iters)
            .into_par_iter()
            .for_each_with(Vec::new(), |data, _| {
                let mut rng = rand::thread_rng();
                let init = rng.gen::<u32>();
                let len = rng.gen_range(lo, hi);
                data.resize(len, 0u8);
                rng.fill(&mut data[..]);

                assert_eq!(
                    fallback(init, &data),
                    hardware.calculate(init, &data, fallback),
                );
            });
    }

    #[test]
    fn random_small() {
        random_chunks(1000, 0, 256);
    }

    #[test]
    fn random_med() {
        random_chunks(1000, 256, 16 * 1024);
    }

    #[test]
    fn random_large() {
        random_chunks(1000, 0, 1024 * 1024);
    }

    quickcheck! {
        fn prop(crc: u32, xs: Vec<u8>) -> bool {
            fallback(crc, &xs) == Hardware::detect().calculate(crc, &xs, fallback)
        }
    }
}