35 lines
550 B
Rust
35 lines
550 B
Rust
//! Cyclic redundancy check function.
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fn crc_accum(a: u32) -> u32
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{
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if a & 1 == 1 {
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0xedb88320 ^ 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 in 0..256 {
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t[n] = (0..8).fold(n as u32, |a, _| crc_accum(a));
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}
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t
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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()
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.fold(s, |a, &o| a >> 8 ^ t[(a & 0xff ^ o as u32) as usize])
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}
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#[test]
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fn crc32_lorem_ipsum()
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{
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assert_eq!(crc32(b"Lorem ipsum dolor sit amet", !0), 0x5F29D461);
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}
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// EOF
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