From ca4920205258a469337332064e5293823a2bc7ab Mon Sep 17 00:00:00 2001 From: cscherr Date: Wed, 9 Jul 2025 17:10:08 +0200 Subject: [PATCH] feat: CRC-32 implemented --- Cargo.lock | 3 ++ Cargo.toml | 2 +- crates/crc/Cargo.toml | 1 + crates/crc/src/crc_32.rs | 83 +++++++++++++++++++++++++++++++++++++++ crates/crc/src/crc_dev.rs | 23 ----------- crates/crc/src/lib.rs | 71 +++++++++++++++++++++++++++++---- 6 files changed, 151 insertions(+), 32 deletions(-) delete mode 100755 crates/crc/src/crc_dev.rs diff --git a/Cargo.lock b/Cargo.lock index d094e9f..8cc5816 100755 --- a/Cargo.lock +++ b/Cargo.lock @@ -95,6 +95,9 @@ dependencies = [ [[package]] name = "crc" version = "0.1.0" +dependencies = [ + "num-traits", +] [[package]] name = "critical-section" diff --git a/Cargo.toml b/Cargo.toml index abcd512..e00f98e 100755 --- a/Cargo.toml +++ b/Cargo.toml @@ -17,7 +17,7 @@ panic-probe = { version = "0.3", features = ["print-defmt"] } [features] default = ["buildscript"] -buildscript = [] +buildscript = [] # runs build.rs [profile.release] debug = "full" # those are not on the board diff --git a/crates/crc/Cargo.toml b/crates/crc/Cargo.toml index 585d3ea..8886b09 100755 --- a/crates/crc/Cargo.toml +++ b/crates/crc/Cargo.toml @@ -4,3 +4,4 @@ version = "0.1.0" edition = "2024" [dependencies] +num-traits = { version = "0.2.19", default-features = false } diff --git a/crates/crc/src/crc_32.rs b/crates/crc/src/crc_32.rs index e69de29..614daa5 100755 --- a/crates/crc/src/crc_32.rs +++ b/crates/crc/src/crc_32.rs @@ -0,0 +1,83 @@ +//! See RFC1662 Appendix C.3 +//! +//! [Link](https://datatracker.ietf.org/doc/html/rfc1662#appendix-C.3) + +use crate::Crc; + +/// Lookup table from RFC1662 C.3 +pub const CRC32_TABLE: [u32; 256] = [ + 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, + 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, + 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, + 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, + 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, + 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, + 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, + 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, + 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, + 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, + 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, + 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, + 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, + 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, + 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, + 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, + 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, + 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, + 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, + 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, + 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, + 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, + 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, + 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, + 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, + 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, + 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, + 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, + 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, + 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, + 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, + 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d, +]; +/// Initial Value from RFC1662 +pub const CRC32_INIT: u32 = 0xffffffff; + +/// Implements CRC-32/ISO-HDLC with look up table +pub struct Crc32(::Checksum); +impl Crc32 {} +impl Crc for Crc32 { + type Input = [u8]; + type Checksum = u32; + + fn new() -> Self { + Self(Self::Checksum::default()) + } + fn shift_reg(&mut self) -> &mut Self::Checksum { + &mut self.0 + } + fn process(&mut self, data: &Self::Input) { + let chksum = self.shift_reg(); + *chksum = CRC32_INIT; + for byte in data { + *chksum ^= *byte as u32; + *chksum = (*chksum >> 8) ^ CRC32_TABLE[(*chksum & 0xff) as usize]; + } + *chksum ^= CRC32_INIT; + } +} + +#[cfg(test)] +mod tests { + use crate::CHECK_DATA; + + use super::*; + + #[test] + fn test_check() { + let mut c = Crc32::new(); + c.process(&CHECK_DATA); + // see https://reveng.sourceforge.io/crc-catalogue/17plus.htm#crc.cat-bits.32 for the check + // value + assert_eq!(*c.shift_reg(), 0xCBF43926); + } +} diff --git a/crates/crc/src/crc_dev.rs b/crates/crc/src/crc_dev.rs deleted file mode 100755 index 56c2512..0000000 --- a/crates/crc/src/crc_dev.rs +++ /dev/null @@ -1,23 +0,0 @@ -use crate::Crc; - -struct CrcDev; -impl Crc for CrcDev { - type Input = [u8]; - type Checksum = [u8; Self::CHECKSUM_LEN]; - const CHECKSUM_LEN: usize = 4; - - fn process(data: &Self::Input) -> Self::Checksum { - todo!() - } -} - -#[cfg(test)] -mod tests { - use super::*; - - #[test] - fn it_works() { - let data = [0, 1, 2, 3, 4, 5, 6]; - assert_eq!(CrcDev::process(&data), [1, 2, 3, 4]) - } -} diff --git a/crates/crc/src/lib.rs b/crates/crc/src/lib.rs index 34884aa..7ee725a 100755 --- a/crates/crc/src/lib.rs +++ b/crates/crc/src/lib.rs @@ -1,16 +1,71 @@ -#![no_std] +//! # CRC's from scratch, nothing else +//! +//! This crate implements some CRC algorithms from scratch in a `no_std` environment. +//! +//! ## Acknowledgements +//! +//! Many thanks to the [crc-catalogue](https://reveng.sourceforge.io/crc-catalogue/) for providing +//! some test vectors. + +#![cfg_attr(not(test), no_std)] + +use num_traits::{AsPrimitive, Num, PrimInt, Unsigned}; mod crc_32; -pub use crc_32::*; -// for testing purposes -mod crc_dev; -pub use crc_dev::*; +pub const CHECK_DATA: [u8; 9] = *b"123456789"; + +pub use crc_32::*; pub trait Crc { type Input: ?Sized; - type Checksum: Eq; - const CHECKSUM_LEN: usize; + type Checksum: Eq + Default; - fn process(data: &Self::Input) -> Self::Checksum; + fn new() -> Self; + fn process(&mut self, data: &Self::Input); + fn shift_reg(&mut self) -> &mut Self::Checksum; +} + +pub fn bit_at>(mut n: N, idx: usize) -> u8 +where + u8: AsPrimitive, +{ + n = n & (1.as_() << idx); + (n >> idx).as_() +} + +#[cfg(test)] +mod test { + use crate::bit_at; + + #[test] + fn test_bit_at() { + let a: u8 = 0b11110000; + assert_eq!(bit_at(a, 0), 0); + assert_eq!(bit_at(a, 1), 0); + assert_eq!(bit_at(a, 2), 0); + assert_eq!(bit_at(a, 3), 0); + assert_eq!(bit_at(a, 4), 1); + assert_eq!(bit_at(a, 5), 1); + assert_eq!(bit_at(a, 6), 1); + assert_eq!(bit_at(a, 7), 1); + + let a: u16 = 0b1111000011110101; + assert_eq!(bit_at(a, 0), 1); + assert_eq!(bit_at(a, 1), 0); + assert_eq!(bit_at(a, 2), 1); + assert_eq!(bit_at(a, 3), 0); + assert_eq!(bit_at(a, 4), 1); + assert_eq!(bit_at(a, 5), 1); + assert_eq!(bit_at(a, 6), 1); + assert_eq!(bit_at(a, 7), 1); + assert_eq!(bit_at(a, 8), 0); + assert_eq!(bit_at(a, 9), 0); + assert_eq!(bit_at(a, 10), 0); + assert_eq!(bit_at(a, 11), 0); + assert_eq!(bit_at(a, 12), 1); + assert_eq!(bit_at(a, 13), 1); + assert_eq!(bit_at(a, 14), 1); + assert_eq!(bit_at(a, 15), 1); + } }