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#![no_std] extern crate byteorder; extern crate gimli_permutation; use core::cmp; use byteorder::{ ByteOrder, LittleEndian }; use gimli_permutation::{ S, gimli }; pub const RATE: usize = 16; #[derive(Clone)] pub struct GimliHash { state: [u32; S], pos: usize } impl Default for GimliHash { fn default() -> Self { GimliHash { state: [0; S], pos: 0 } } } impl GimliHash { #[inline] pub fn update(&mut self, buf: &[u8]) { self.absorb(buf); } #[inline] pub fn finalize(self, buf: &mut [u8]) { self.xof().squeeze(buf); } #[inline] pub fn xof(mut self) -> XofReader { self.pad(); XofReader { state: self.state, pos: 0 } } fn absorb(&mut self, buf: &[u8]) { let GimliHash { state, pos } = self; let mut start = 0; let mut len = buf.len(); while len > 0 { let take = cmp::min(RATE - *pos, len); with(state, |state| { for (dst, &src) in state[*pos..][..take].iter_mut() .zip(&buf[start..][..take]) { *dst ^= src; } *pos += take; start += take; len -= take; }); if *pos == RATE { gimli(state); *pos = 0; } } } fn pad(&mut self) { let &mut GimliHash { ref mut state, pos } = self; with(state, |state| { state[pos] ^= 0x1f; state[RATE - 1] ^= 0x80; }); gimli(state); } } pub struct XofReader { state: [u32; S], pos: usize } impl XofReader { pub fn squeeze(&mut self, buf: &mut [u8]) { let XofReader { state, pos } = self; let take = cmp::min(RATE - *pos, buf.len()); let (prefix, buf) = buf.split_at_mut(take); if !prefix.is_empty() { with(state, |state| { prefix.copy_from_slice(&state[*pos..][..take]); *pos += take; }); if *pos == RATE { gimli(state); *pos = 0; } } for chunk in buf.chunks_mut(RATE) { let take = chunk.len(); with(state, |state| { chunk.copy_from_slice(&state[*pos..][..take]); }); if *pos == RATE { gimli(state); } else { *pos += take; } } } } fn with<F>(state: &mut [u32; S], f: F) where F: FnOnce(&mut [u8; S * 4]) { #[inline] fn transmute(arr: &mut [u32; S]) -> &mut [u8; S * 4] { unsafe { &mut *(arr as *mut [u32; S] as *mut [u8; S * 4]) } } LittleEndian::from_slice_u32(state); f(transmute(state)); LittleEndian::from_slice_u32(state); }