Zlib-rs is faster than C

I found out I already know Rust:

        unsafe {
            let x_tmp0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x10);
            xmm_crc0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x01);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, x_tmp0);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, xmm_crc0);

Kidding aside, I thought the purpose of Rust was for safety but the keyword unsafe is sprinkled liberally throughout this library. At what point does it really stop mattering if this is C or Rust?

Presumably with inline assembly both languages can emit what is effectively the same machine code. Is the Rust compiler a better optimizing compiler than C compilers?

To quote the Rust book (https://doc.rust-lang.org/book/ch20-01-unsafe-rust.html):

  In addition, unsafe does not mean the code inside the
  block is necessarily dangerous or that it will definitely
  have memory safety problems: the intent is that as the
  programmer, you’ll ensure the code inside an unsafe block
  will access memory in a valid way.

Since you say you already know that much Rust, you can be that programmer!

I feel like C programmers had the same idea, and well, we see how that works out in practice.

No, C lacks encapsulation of unsafe code. This is very important. Encapsulation is the only way to scale local reasoning into global correctness.

Eh. Good C programmers know what's safe and what's not. Often comments call out sketchy stuff. Just because it's not a language keyword, doesnt mean it's not called out.

Bad C programmers though? Their stuff is more dangerous and they don't know when and don't call it out and should probably stick to Rust.