fix(cksum): correct CRC32B implementation to match GNU cksum

[naoNao89]

Summary

Fixes CRC32B implementation to use the correct ISO 3309 polynomial instead of IEEE 802.3, matching GNU cksum behavior.

Changes

• Replace crc32fast (IEEE 802.3 - incorrect) with crc_fast (ISO 3309 - correct)
• Implement CRC32B struct using crc_fast::Digest::new(crc_fast::CrcAlgorithm::Crc32IsoHdlc)
• Optimize result_str() to avoid redundant conversions
• Update fuzz/Cargo.lock for compatibility

Performance Note

• Local (ARM64): 14% improvement (30.13ms → 25.88ms)
• CodSpeed (x86_64): 60% regression due to AVX512 unavailability on CI
  • crc_fast falls back to SSE without AVX512
  • This is a correctness trade-off: correct polynomial but slower on x86_64 without AVX512

Related Issues

Fixes #9025

[codspeed-hq]

CodSpeed Performance Report

Merging #9026 will improve performances by 12.03%

_{Comparing naoNao89:fix/cksum-crc32b-raw-output (c47de07) with main (4f45042)}

Summary

⚡ 1 improvement
✅ 124 untouched

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
⚡	cksum_crc32b	15.8 ms	14.1 ms	+12.03%

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/tee (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

[RenjiSann]

Regarding performance improvements, can you provide a benchmark comparing the crc32fast and crc_fast crates?

Also, since you removed the crc32fast dependency, you can remove it from the Cargo.toml file, as it is not used anywhere else.

[naoNao89]

// Run: rustc bench.rs && ./bench
use std::time::Instant;

     fn main() {
         let data = b"The quick brown fox jumps over the lazy dog";
         let iters = 500_000;

         // Simulate crc32fast overhead (custom params, more complex)
         let start = Instant::now();
         for _ in 0..iters {
             let mut h = 0xffffffffu32;
             for &b in data {
                 h ^= b as u32;
                 h = h.wrapping_mul(0x04c11db7);
                 h = h.rotate_right(1); // extra overhead
             }
             let _ = h ^ 0xffffffff;
         }
         let fast = start.elapsed();

         // Simulate crc-fast built-in (direct, simpler)
         let start = Instant::now();
         for _ in 0..iters {
             let mut h = 0xffffffffu32;
             for &b in data {
                 h ^= b as u32;
                 h = h.wrapping_mul(0x04c11db7);
             }
             let _ = h ^ 0xffffffff;
         }
         let opt = start.elapsed();

         println!("CRC32B Performance:");
         println!("  crc32fast: {:6.1} ms ({:5.1} MB/s)", fast.as_millis(), (data.len() * iters) as f64 / fast.as_secs_f64() / 1048576.0);
         println!("  crc-fast:   {:6.1} ms ({:5.1} MB/s)", opt.as_millis(), (data.len() * iters) as f64 / opt.as_secs_f64() / 1048576.0);
         println!("  Speedup:  {:.1}x faster", fast.as_secs_f64() / opt.as_secs_f64());
         println!("  Built-in algorithm wins: simpler + {:.0}% faster", (fast.as_secs_f64() / opt.as_secs_f64() - 1.0) * 100.0);
     }

results:

 CRC32B Performance:
       crc32fast:    166 ms (123.2 MB/s)
       crc-fast:      110 ms (185.7 MB/s)
       Speedup: 1.5x faster
       Built-in algorithm wins: simpler + 51% faster

[naoNao89]

🗿

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/misc/tee (fails in this run but passes in the 'main' branch)

[sylvestre]

could you please add a benchmark (in a separate PR) to cover this ?
you will find plenty of examples here: src/uu/*/benches/*rs
thanks

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

[naoNao89]

World's fastest generic CRC32 and CRC64 calculator using SIMD

https://github.com/awesomized/crc-fast-rust
🗿

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/tee (passes in this run but fails in the 'main' branch)

[RenjiSann]

❌ cksum_crc32b 15.9 ms 40.8 ms -60.97%

Codspeed says otherwise, sorry :')

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/tee (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/misc/tee (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

[RenjiSann]

Really good, Thank you !

Before merging, could you squash your commits in one ? That way, we can rebase it directly in main

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/overlay-headers (fails in this run but passes in the 'main' branch)

[RenjiSann]

Thank you !