Reduce amount of unsafe (#540)

Author: newpavlov

belt-hash/src/lib.rs

@@ -158,7 +158,6 @@ pub fn belt_compress(x1: [u32; 4], x2: [u32; 4], x34: [u32; 8]) -> ([u32; 4], [u
 
 #[inline(always)]
 fn xor(a: [u32; 4], b: [u32; 4]) -> [u32; 4] {
-    // TODO: use array zip on stabilization and MSRV bump
     [a[0] ^ b[0], a[1] ^ b[1], a[2] ^ b[2], a[3] ^ b[3]]
 }
 

blake2/src/lib.rs

@@ -13,7 +13,7 @@ extern crate std;
 
 pub use digest::{self, Digest};
 
-use core::{convert::TryInto, fmt, marker::PhantomData, ops::Div};
+use core::{fmt, marker::PhantomData, ops::Div};
 use digest::{
     array::{Array, ArraySize},
     block_buffer::{Lazy, LazyBuffer},

gost94/src/gost94_core.rs

@@ -1,5 +1,5 @@
 #![allow(clippy::many_single_char_names)]
-use core::{convert::TryInto, fmt};
+use core::fmt;
 use digest::{
     block_buffer::Eager,
     core_api::{

groestl/src/compress1024.rs

@@ -1,6 +1,5 @@
 #![allow(clippy::needless_range_loop)]
 use crate::table::TABLE;
-use core::{convert::TryInto, u64};
 
 pub(crate) const COLS: usize = 16;
 const ROUNDS: u64 = 14;

groestl/src/compress512.rs

@@ -1,6 +1,5 @@
 #![allow(clippy::needless_range_loop)]
 use crate::table::TABLE;
-use core::{convert::TryInto, u64};
 
 pub(crate) const COLS: usize = 8;
 const ROUNDS: u64 = 10;

jh/benches/machine.rs

@@ -22,7 +22,7 @@ macro_rules! mach_bench {
                 input: *const [u8; 64],
             ) {
                 for _ in 0..160 {
-                    jh::f8_impl(m, state, input as *const _);
+                    jh::f8_impl(m, state, input.cast());
                 }
             }
             b.iter(|| unsafe { runner(m, &mut state, &input) });

jh/src/compressor.rs

@@ -97,7 +97,7 @@ union X2Bytes<M: Machine> {
 #[doc(hidden)]
 pub fn f8_impl<M: Machine>(mach: M, state: &mut [vec128_storage; 8], data: *const u8) {
     #[allow(clippy::cast_ptr_alignment)]
-    let data = data as *const M::u128x1;
+    let data: *const M::u128x1 = data.cast();
     let mut y = X8::<M>(
         mach.unpack(state[0]),
         mach.unpack(state[1]),

md4/src/lib.rs

@@ -9,7 +9,7 @@
 
 pub use digest::{self, Digest};
 
-use core::{convert::TryInto, fmt, num::Wrapping as W};
+use core::{fmt, num::Wrapping as W};
 #[cfg(feature = "oid")]
 use digest::const_oid::{AssociatedOid, ObjectIdentifier};
 use digest::{

md5/src/compress/soft.rs

@@ -1,6 +1,5 @@
 #![allow(clippy::many_single_char_names, clippy::unreadable_literal)]
 use crate::consts::RC;
-use core::convert::TryInto;
 
 #[inline(always)]
 fn op_f(w: u32, x: u32, y: u32, z: u32, m: u32, c: u32, s: u32) -> u32 {

md5/src/lib.rs

@@ -15,6 +15,7 @@ use core::{fmt, slice::from_ref};
 #[cfg(feature = "oid")]
 use digest::const_oid::{AssociatedOid, ObjectIdentifier};
 use digest::{
+    array::ArrayOps,
     block_buffer::Eager,
     core_api::{
         AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, CoreWrapper, FixedOutputCore,
@@ -49,7 +50,8 @@ impl UpdateCore for Md5Core {
     #[inline]
     fn update_blocks(&mut self, blocks: &[Block<Self>]) {
         self.block_len = self.block_len.wrapping_add(blocks.len() as u64);
-        compress::compress(&mut self.state, convert(blocks))
+        let blocks = ArrayOps::cast_slice_to_core(blocks);
+        compress::compress(&mut self.state, blocks)
     }
 }
 
@@ -62,9 +64,7 @@ impl FixedOutputCore for Md5Core {
             .wrapping_add(buffer.get_pos() as u64)
             .wrapping_mul(8);
         let mut s = self.state;
-        buffer.len64_padding_le(bit_len, |b| {
-            compress::compress(&mut s, convert(from_ref(b)))
-        });
+        buffer.len64_padding_le(bit_len, |b| compress::compress(&mut s, from_ref(&b.0)));
         for (chunk, v) in out.chunks_exact_mut(4).zip(s.iter()) {
             chunk.copy_from_slice(&v.to_le_bytes());
         }
@@ -108,13 +108,3 @@ impl AssociatedOid for Md5Core {
 
 /// MD5 hasher state.
 pub type Md5 = CoreWrapper<Md5Core>;
-
-const BLOCK_SIZE: usize = <Md5Core as BlockSizeUser>::BlockSize::USIZE;
-
-#[inline(always)]
-fn convert(blocks: &[Block<Md5Core>]) -> &[[u8; BLOCK_SIZE]] {
-    // SAFETY: Array<u8, U64> and [u8; 64] have
-    // exactly the same memory layout
-    let p = blocks.as_ptr() as *const [u8; BLOCK_SIZE];
-    unsafe { core::slice::from_raw_parts(p, blocks.len()) }
-}