sha2/
sha256.rs

1use digest::{generic_array::GenericArray, typenum::U64};
2
3cfg_if::cfg_if! {
4    if #[cfg(feature = "force-soft")] {
5        mod soft;
6        use soft::compress;
7    } else if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
8        #[cfg(not(feature = "asm"))]
9        mod soft;
10        #[cfg(feature = "asm")]
11        mod soft {
12            pub(crate) use sha2_asm::compress256 as compress;
13        }
14        mod x86;
15        use x86::compress;
16    } else if #[cfg(all(feature = "asm", target_arch = "aarch64"))] {
17        mod soft;
18        mod aarch64;
19        use aarch64::compress;
20    } else {
21        mod soft;
22        use soft::compress;
23    }
24}
25
26/// Raw SHA-256 compression function.
27///
28/// This is a low-level "hazmat" API which provides direct access to the core
29/// functionality of SHA-256.
30#[cfg_attr(docsrs, doc(cfg(feature = "compress")))]
31pub fn compress256(state: &mut [u32; 8], blocks: &[GenericArray<u8, U64>]) {
32    // SAFETY: GenericArray<u8, U64> and [u8; 64] have
33    // exactly the same memory layout
34    let p = blocks.as_ptr() as *const [u8; 64];
35    let blocks = unsafe { core::slice::from_raw_parts(p, blocks.len()) };
36    compress(state, blocks)
37}