sha2/
sha256.rs

1use digest::{generic_array::GenericArray, typenum::U64};
2
3cfg_if::cfg_if! {
4    if #[cfg(feature = "force-soft-compact")] {
5        mod soft_compact;
6        use soft_compact::compress;
7    } else if #[cfg(feature = "force-soft")] {
8        mod soft;
9        use soft::compress;
10    } else if #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] {
11        #[cfg(not(feature = "asm"))]
12        mod soft;
13        #[cfg(feature = "asm")]
14        mod soft {
15            pub(crate) use sha2_asm::compress256 as compress;
16        }
17        mod x86;
18        use x86::compress;
19    } else if #[cfg(all(feature = "asm", target_arch = "aarch64"))] {
20        mod soft;
21        mod aarch64;
22        use aarch64::compress;
23    } else if #[cfg(all(feature = "loongarch64_asm", target_arch = "loongarch64"))] {
24        mod loongarch64_asm;
25        use loongarch64_asm::compress;
26    } else {
27        mod soft;
28        use soft::compress;
29    }
30}
31
32/// Raw SHA-256 compression function.
33///
34/// This is a low-level "hazmat" API which provides direct access to the core
35/// functionality of SHA-256.
36#[cfg_attr(docsrs, doc(cfg(feature = "compress")))]
37pub fn compress256(state: &mut [u32; 8], blocks: &[GenericArray<u8, U64>]) {
38    // SAFETY: GenericArray<u8, U64> and [u8; 64] have
39    // exactly the same memory layout
40    let p = blocks.as_ptr() as *const [u8; 64];
41    let blocks = unsafe { core::slice::from_raw_parts(p, blocks.len()) };
42    compress(state, blocks)
43}