Remove dependency on packed_simd by using SIMD intrinsics.

The resulting code is a little ugly, but not too bad.

This allows the crate to compile on stable.

Cargo.toml

@@ -17,7 +17,6 @@ exclude = [
 
 [dependencies]
 arrayref = "0.3.6"
-packed_simd = { version = "0.3.4", package = "packed_simd_2" }
 
 [dev-dependencies]
 librsync = { git = "https://github.com/goffrie/librsync-rs", rev = "56e7646d133c3174656b66c61f6259d6154a8873", default-features = false }

README.md

@@ -9,9 +9,7 @@ A faster implementation of [librsync](https://github.com/librsync/librsync) in
 pure Rust, using SIMD operations where available. Note that only the legacy MD4
 format is supported, not BLAKE2.
 
-Rust nightly is currently required because of
-[packed\_simd](https://github.com/rust-lang/packed_simd). Only x86 and x86-64
-architectures are currently supported.
+Only x86 and x86-64 architectures are currently supported for SIMD.
 
 ## The rsync algorithm
 This crate offers three major APIs:

rust-toolchain

@@ -1 +1 @@
-nightly-2020-10-13
+1.47.0

src/crc.rs

@@ -71,11 +71,15 @@ impl Crc {
         {
             if is_x86_feature_detected!("avx2") {
                 imp!(#[target_feature(enable = "avx2")] unsafe fn imp_avx2);
-                unsafe { return imp_avx2(self, buf); }
+                unsafe {
+                    return imp_avx2(self, buf);
+                }
             }
             if is_x86_feature_detected!("sse2") {
                 imp!(#[target_feature(enable = "sse2")] unsafe fn imp_sse2);
-                unsafe { return imp_sse2(self, buf); }
+                unsafe {
+                    return imp_sse2(self, buf);
+                }
             }
         }
         imp!(fn imp_baseline);