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//! Assembly implementation of [SHA-1][1] compression function.
//!
//! For full SHA-1 hash function with this implementation of compression function
//! use [sha-1](https://crates.io/crates/sha-1) crate with
//! the enabled "asm" feature.
//! 
//! Only x86 and x86-64 architectures are currently supported.
//! 
//! [1]: https://en.wikipedia.org/wiki/SHA-1

#![no_std]
extern crate generic_array;

use generic_array::GenericArray;
use generic_array::typenum::U64;
use core::mem;

type BlockSize = U64;
type Block = GenericArray<u8, BlockSize>;

#[link(name="sha1", kind="static")]
extern "C" {
    fn sha1_compress(state: &mut [u32; 5], block: &[u8; 64]);
}

/// Safe wrapper around assembly implementation of SHA-1 compression function
#[inline]
pub fn compress(state: &mut [u32; 5], block: &Block) {
    unsafe {
        sha1_compress(state, mem::transmute(block));
    }
}