Coverage Report

Created: 2026-09-04 06:40

next uncovered line (L), next uncovered region (R), next uncovered branch (B)
/rust/registry/src/index.crates.io-1949cf8c6b5b557f/crc32fast-1.5.1/src/baseline.rs
Line
Count
Source
1
use crate::table::CRC32_TABLE;
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3
#[derive(Clone)]
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pub struct State {
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    state: u32,
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}
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impl State {
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0
    pub fn new(state: u32) -> Self {
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0
        State { state }
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0
    }
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0
    pub fn update(&mut self, buf: &[u8]) {
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0
        self.state = update_fast_16(self.state, buf);
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0
    }
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0
    pub fn finalize(self) -> u32 {
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0
        self.state
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0
    }
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0
    pub fn reset(&mut self) {
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0
        self.state = 0;
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0
    }
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0
    pub fn combine(&mut self, other: u32, amount: u64) {
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0
        self.state = crate::combine::combine(self.state, other, amount);
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0
    }
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}
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6.49k
pub(crate) fn update_fast_16(prev: u32, mut buf: &[u8]) -> u32 {
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    const UNROLL: usize = 4;
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    const BYTES_AT_ONCE: usize = 16 * UNROLL;
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6.49k
    let mut crc = !prev;
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6.49k
    while buf.len() >= BYTES_AT_ONCE {
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0
        for _ in 0..UNROLL {
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0
            let w0 = u32::from_le_bytes([buf[0], buf[1], buf[2], buf[3]]) ^ crc;
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0
            crc = CRC32_TABLE[0x0][buf[0xf] as usize]
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0
                ^ CRC32_TABLE[0x1][buf[0xe] as usize]
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0
                ^ CRC32_TABLE[0x2][buf[0xd] as usize]
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0
                ^ CRC32_TABLE[0x3][buf[0xc] as usize]
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0
                ^ CRC32_TABLE[0x4][buf[0xb] as usize]
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0
                ^ CRC32_TABLE[0x5][buf[0xa] as usize]
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0
                ^ CRC32_TABLE[0x6][buf[0x9] as usize]
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0
                ^ CRC32_TABLE[0x7][buf[0x8] as usize]
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0
                ^ CRC32_TABLE[0x8][buf[0x7] as usize]
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0
                ^ CRC32_TABLE[0x9][buf[0x6] as usize]
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0
                ^ CRC32_TABLE[0xa][buf[0x5] as usize]
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0
                ^ CRC32_TABLE[0xb][buf[0x4] as usize]
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0
                ^ CRC32_TABLE[0xc][(w0 >> 24) as usize]
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0
                ^ CRC32_TABLE[0xd][((w0 >> 16) & 0xFF) as usize]
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0
                ^ CRC32_TABLE[0xe][((w0 >> 8) & 0xFF) as usize]
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0
                ^ CRC32_TABLE[0xf][(w0 & 0xFF) as usize];
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0
            buf = &buf[16..];
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0
        }
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    }
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6.49k
    update_slow(!crc, buf)
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6.49k
}
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62
6.49k
pub(crate) fn update_slow(prev: u32, buf: &[u8]) -> u32 {
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6.49k
    let mut crc = !prev;
64
65
13.4k
    for &byte in buf.iter() {
66
13.4k
        crc = CRC32_TABLE[0][((crc as u8) ^ byte) as usize] ^ (crc >> 8);
67
13.4k
    }
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6.49k
    !crc
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6.49k
}
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#[cfg(test)]
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mod test {
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    #[test]
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    fn slow() {
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        assert_eq!(super::update_slow(0, b""), 0);
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        // test vectors from the iPXE project (input and output are bitwise negated)
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        assert_eq!(super::update_slow(!0x12345678, b""), !0x12345678);
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        assert_eq!(super::update_slow(!0xffffffff, b"hello world"), !0xf2b5ee7a);
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        assert_eq!(super::update_slow(!0xffffffff, b"hello"), !0xc9ef5979);
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        assert_eq!(super::update_slow(!0xc9ef5979, b" world"), !0xf2b5ee7a);
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        // Some vectors found on Rosetta code
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        assert_eq!(super::update_slow(0, b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"), 0x190A55AD);
86
        assert_eq!(super::update_slow(0, b"\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"), 0xFF6CAB0B);
87
        assert_eq!(super::update_slow(0, b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F"), 0x91267E8A);
88
    }
89
90
    quickcheck::quickcheck! {
91
        fn fast_16_is_the_same_as_slow(crc: u32, bytes: Vec<u8>) -> bool {
92
            super::update_fast_16(crc, &bytes) == super::update_slow(crc, &bytes)
93
        }
94
    }
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}