37 lines
674 B
Rust
37 lines
674 B
Rust
//! Cyclic redundancy check function.
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fn crc_accum(a: u32, _: u32) -> u32
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{
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if a & 1 == 1 {
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0xEDB8_8320 ^ a >> 1
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} else {
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a >> 1
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}
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}
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fn crc_init() -> [u32; 256]
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{
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let mut t = [0; 256];
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for (n, v) in t.iter_mut().enumerate() {
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*v = (0..8).fold(n as u32, crc_accum);
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}
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t
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}
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/// Creates a CRC-32 of all bytes in `b` with the starting sum `s`.
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///
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/// # Examples
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///
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/// ```
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/// use maraiah::durandal::crc::crc32;
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///
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/// assert_eq!(crc32(b"Lorem ipsum dolor sit amet", !0), 0x5F29_D461);
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/// ```
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pub fn crc32(b: &[u8], s: u32) -> u32
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{
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let t = crc_init();
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!b.iter().fold(s, |a, &o| a >> 8 ^ t[usize::from(a as u8 ^ o)])
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}
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// EOF
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