vendor/siphasher-0.3.11/src/sip.rs - toolchain/rustc - Git at Google

 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.

 //! An implementation of SipHash.

 use core::cmp;
 use core::hash;
 use core::hash::Hasher as _;
 use core::marker::PhantomData;
 use core::mem;
 use core::ptr;
 use core::u64;

 /// An implementation of SipHash 1-3.
 ///
 /// See: <https://www.aumasson.jp/siphash/siphash.pdf>
 #[derive(Debug, Clone, Copy, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct SipHasher13 {
     hasher: Hasher<Sip13Rounds>,
 }

 /// An implementation of SipHash 2-4.
 ///
 /// See: <https://www.aumasson.jp/siphash/siphash.pdf>
 #[derive(Debug, Clone, Copy, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct SipHasher24 {
     hasher: Hasher<Sip24Rounds>,
 }

 /// An implementation of SipHash 2-4.
 ///
 /// See: <https://www.aumasson.jp/siphash/siphash.pdf>
 ///
 /// SipHash is a general-purpose hashing function: it runs at a good
 /// speed (competitive with Spooky and City) and permits strong _keyed_
 /// hashing. This lets you key your hashtables from a strong RNG, such as
 /// [`rand::os::OsRng`](https://doc.rust-lang.org/rand/rand/os/struct.OsRng.html).
 ///
 /// Although the SipHash algorithm is considered to be generally strong,
 /// it is not intended for cryptographic purposes. As such, all
 /// cryptographic uses of this implementation are _strongly discouraged_.
 #[derive(Debug, Clone, Copy, Default)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct SipHasher(SipHasher24);

 #[derive(Debug, Clone, Copy)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 struct Hasher<S: Sip> {
     k0: u64,
     k1: u64,
     length: usize, // how many bytes we've processed
     state: State,  // hash State
     tail: u64,     // unprocessed bytes le
     ntail: usize,  // how many bytes in tail are valid
     _marker: PhantomData<S>,
 }

 #[derive(Debug, Clone, Copy)]
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 struct State {
     // v0, v2 and v1, v3 show up in pairs in the algorithm,
     // and simd implementations of SipHash will use vectors
     // of v02 and v13. By placing them in this order in the struct,
     // the compiler can pick up on just a few simd optimizations by itself.
     v0: u64,
     v2: u64,
     v1: u64,
     v3: u64,
 }

 macro_rules! compress {
     ($state:expr) => {{
         compress!($state.v0, $state.v1, $state.v2, $state.v3)
     }};
     ($v0:expr, $v1:expr, $v2:expr, $v3:expr) => {{
         $v0 = $v0.wrapping_add($v1);
         $v1 = $v1.rotate_left(13);
         $v1 ^= $v0;
         $v0 = $v0.rotate_left(32);
         $v2 = $v2.wrapping_add($v3);
         $v3 = $v3.rotate_left(16);
         $v3 ^= $v2;
         $v0 = $v0.wrapping_add($v3);
         $v3 = $v3.rotate_left(21);
         $v3 ^= $v0;
         $v2 = $v2.wrapping_add($v1);
         $v1 = $v1.rotate_left(17);
         $v1 ^= $v2;
         $v2 = $v2.rotate_left(32);
     }};
 }

 /// Loads an integer of the desired type from a byte stream, in LE order. Uses
 /// `copy_nonoverlapping` to let the compiler generate the most efficient way
 /// to load it from a possibly unaligned address.
 ///
 /// Unsafe because: unchecked indexing at `i..i+size_of(int_ty)`
 macro_rules! load_int_le {
     ($buf:expr, $i:expr, $int_ty:ident) => {{
         debug_assert!($i + mem::size_of::<$int_ty>() <= $buf.len());
         let mut data = 0 as $int_ty;
         ptr::copy_nonoverlapping(
             $buf.as_ptr().add($i),
             &mut data as *mut _ as *mut u8,
             mem::size_of::<$int_ty>(),
         );
         data.to_le()
     }};
 }

 /// Loads a u64 using up to 7 bytes of a byte slice. It looks clumsy but the
 /// `copy_nonoverlapping` calls that occur (via `load_int_le!`) all have fixed
 /// sizes and avoid calling `memcpy`, which is good for speed.
 ///
 /// Unsafe because: unchecked indexing at start..start+len
 #[inline]
 unsafe fn u8to64_le(buf: &[u8], start: usize, len: usize) -> u64 {
     debug_assert!(len < 8);
     let mut i = 0; // current byte index (from LSB) in the output u64
     let mut out = 0;
     if i + 3 < len {
         out = load_int_le!(buf, start + i, u32) as u64;
         i += 4;
     }
     if i + 1 < len {
         out |= (load_int_le!(buf, start + i, u16) as u64) << (i * 8);
         i += 2
     }
     if i < len {
         out |= (*buf.get_unchecked(start + i) as u64) << (i * 8);
         i += 1;
     }
     debug_assert_eq!(i, len);
     out
 }

 impl SipHasher {
     /// Creates a new `SipHasher` with the two initial keys set to 0.
     #[inline]
     pub fn new() -> SipHasher {
         SipHasher::new_with_keys(0, 0)
     }

     /// Creates a `SipHasher` that is keyed off the provided keys.
     #[inline]
     pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher {
         SipHasher(SipHasher24::new_with_keys(key0, key1))
     }

     /// Creates a `SipHasher` from a 16 byte key.
     pub fn new_with_key(key: &[u8; 16]) -> SipHasher {
         let mut b0 = [0u8; 8];
         let mut b1 = [0u8; 8];
         b0.copy_from_slice(&key[0..8]);
         b1.copy_from_slice(&key[8..16]);
         let key0 = u64::from_le_bytes(b0);
         let key1 = u64::from_le_bytes(b1);
         Self::new_with_keys(key0, key1)
     }

     /// Get the keys used by this hasher
     pub fn keys(&self) -> (u64, u64) {
         (self.0.hasher.k0, self.0.hasher.k1)
     }

     /// Get the key used by this hasher as a 16 byte vector
     pub fn key(&self) -> [u8; 16] {
         let mut bytes = [0u8; 16];
         bytes[0..8].copy_from_slice(&self.0.hasher.k0.to_le_bytes());
         bytes[8..16].copy_from_slice(&self.0.hasher.k1.to_le_bytes());
         bytes
     }

     /// Hash a byte array - This is the easiest and safest way to use SipHash.
     #[inline]
     pub fn hash(&self, bytes: &[u8]) -> u64 {
         let mut hasher = self.0.hasher;
         hasher.write(bytes);
         hasher.finish()
     }
 }

 impl SipHasher13 {
     /// Creates a new `SipHasher13` with the two initial keys set to 0.
     #[inline]
     pub fn new() -> SipHasher13 {
         SipHasher13::new_with_keys(0, 0)
     }

     /// Creates a `SipHasher13` that is keyed off the provided keys.
     #[inline]
     pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher13 {
         SipHasher13 {
             hasher: Hasher::new_with_keys(key0, key1),
         }
     }

     /// Creates a `SipHasher13` from a 16 byte key.
     pub fn new_with_key(key: &[u8; 16]) -> SipHasher13 {
         let mut b0 = [0u8; 8];
         let mut b1 = [0u8; 8];
         b0.copy_from_slice(&key[0..8]);
         b1.copy_from_slice(&key[8..16]);
         let key0 = u64::from_le_bytes(b0);
         let key1 = u64::from_le_bytes(b1);
         Self::new_with_keys(key0, key1)
     }

     /// Get the keys used by this hasher
     pub fn keys(&self) -> (u64, u64) {
         (self.hasher.k0, self.hasher.k1)
     }

     /// Get the key used by this hasher as a 16 byte vector
     pub fn key(&self) -> [u8; 16] {
         let mut bytes = [0u8; 16];
         bytes[0..8].copy_from_slice(&self.hasher.k0.to_le_bytes());
         bytes[8..16].copy_from_slice(&self.hasher.k1.to_le_bytes());
         bytes
     }

     /// Hash a byte array - This is the easiest and safest way to use SipHash.
     #[inline]
     pub fn hash(&self, bytes: &[u8]) -> u64 {
         let mut hasher = self.hasher;
         hasher.write(bytes);
         hasher.finish()
     }
 }

 impl SipHasher24 {
     /// Creates a new `SipHasher24` with the two initial keys set to 0.
     #[inline]
     pub fn new() -> SipHasher24 {
         SipHasher24::new_with_keys(0, 0)
     }

     /// Creates a `SipHasher24` that is keyed off the provided keys.
     #[inline]
     pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher24 {
         SipHasher24 {
             hasher: Hasher::new_with_keys(key0, key1),
         }
     }

     /// Creates a `SipHasher24` from a 16 byte key.
     pub fn new_with_key(key: &[u8; 16]) -> SipHasher24 {
         let mut b0 = [0u8; 8];
         let mut b1 = [0u8; 8];
         b0.copy_from_slice(&key[0..8]);
         b1.copy_from_slice(&key[8..16]);
         let key0 = u64::from_le_bytes(b0);
         let key1 = u64::from_le_bytes(b1);
         Self::new_with_keys(key0, key1)
     }

     /// Get the keys used by this hasher
     pub fn keys(&self) -> (u64, u64) {
         (self.hasher.k0, self.hasher.k1)
     }

     /// Get the key used by this hasher as a 16 byte vector
     pub fn key(&self) -> [u8; 16] {
         let mut bytes = [0u8; 16];
         bytes[0..8].copy_from_slice(&self.hasher.k0.to_le_bytes());
         bytes[8..16].copy_from_slice(&self.hasher.k1.to_le_bytes());
         bytes
     }

     /// Hash a byte array - This is the easiest and safest way to use SipHash.
     #[inline]
     pub fn hash(&self, bytes: &[u8]) -> u64 {
         let mut hasher = self.hasher;
         hasher.write(bytes);
         hasher.finish()
     }
 }

 impl<S: Sip> Hasher<S> {
     #[inline]
     fn new_with_keys(key0: u64, key1: u64) -> Hasher<S> {
         let mut state = Hasher {
             k0: key0,
             k1: key1,
             length: 0,
             state: State {
                 v0: 0,
                 v1: 0,
                 v2: 0,
                 v3: 0,
             },
             tail: 0,
             ntail: 0,
             _marker: PhantomData,
         };
         state.reset();
         state
     }

     #[inline]
     fn reset(&mut self) {
         self.length = 0;
         self.state.v0 = self.k0 ^ 0x736f6d6570736575;
         self.state.v1 = self.k1 ^ 0x646f72616e646f6d;
         self.state.v2 = self.k0 ^ 0x6c7967656e657261;
         self.state.v3 = self.k1 ^ 0x7465646279746573;
         self.ntail = 0;
     }

     // A specialized write function for values with size <= 8.
     //
     // The hashing of multi-byte integers depends on endianness. E.g.:
     // - little-endian: `write_u32(0xDDCCBBAA)` == `write([0xAA, 0xBB, 0xCC, 0xDD])`
     // - big-endian:    `write_u32(0xDDCCBBAA)` == `write([0xDD, 0xCC, 0xBB, 0xAA])`
     //
     // This function does the right thing for little-endian hardware. On
     // big-endian hardware `x` must be byte-swapped first to give the right
     // behaviour. After any byte-swapping, the input must be zero-extended to
     // 64-bits. The caller is responsible for the byte-swapping and
     // zero-extension.
     #[inline]
     fn short_write<T>(&mut self, _x: T, x: u64) {
         let size = mem::size_of::<T>();
         self.length += size;

         // The original number must be zero-extended, not sign-extended.
         debug_assert!(if size < 8 { x >> (8 * size) == 0 } else { true });

         // The number of bytes needed to fill `self.tail`.
         let needed = 8 - self.ntail;

         self.tail |= x << (8 * self.ntail);
         if size < needed {
             self.ntail += size;
             return;
         }

         // `self.tail` is full, process it.
         self.state.v3 ^= self.tail;
         S::c_rounds(&mut self.state);
         self.state.v0 ^= self.tail;

         self.ntail = size - needed;
         self.tail = if needed < 8 { x >> (8 * needed) } else { 0 };
     }
 }

 impl hash::Hasher for SipHasher {
     #[inline]
     fn write(&mut self, msg: &[u8]) {
         self.0.write(msg)
     }

     #[inline]
     fn finish(&self) -> u64 {
         self.0.finish()
     }

     #[inline]
     fn write_usize(&mut self, i: usize) {
         self.0.write_usize(i);
     }

     #[inline]
     fn write_u8(&mut self, i: u8) {
         self.0.write_u8(i);
     }

     #[inline]
     fn write_u16(&mut self, i: u16) {
         self.0.write_u16(i);
     }

     #[inline]
     fn write_u32(&mut self, i: u32) {
         self.0.write_u32(i);
     }

     #[inline]
     fn write_u64(&mut self, i: u64) {
         self.0.write_u64(i);
     }
 }

 impl hash::Hasher for SipHasher13 {
     #[inline]
     fn write(&mut self, msg: &[u8]) {
         self.hasher.write(msg)
     }

     #[inline]
     fn finish(&self) -> u64 {
         self.hasher.finish()
     }

     #[inline]
     fn write_usize(&mut self, i: usize) {
         self.hasher.write_usize(i);
     }

     #[inline]
     fn write_u8(&mut self, i: u8) {
         self.hasher.write_u8(i);
     }

     #[inline]
     fn write_u16(&mut self, i: u16) {
         self.hasher.write_u16(i);
     }

     #[inline]
     fn write_u32(&mut self, i: u32) {
         self.hasher.write_u32(i);
     }

     #[inline]
     fn write_u64(&mut self, i: u64) {
         self.hasher.write_u64(i);
     }
 }

 impl hash::Hasher for SipHasher24 {
     #[inline]
     fn write(&mut self, msg: &[u8]) {
         self.hasher.write(msg)
     }

     #[inline]
     fn finish(&self) -> u64 {
         self.hasher.finish()
     }

     #[inline]
     fn write_usize(&mut self, i: usize) {
         self.hasher.write_usize(i);
     }

     #[inline]
     fn write_u8(&mut self, i: u8) {
         self.hasher.write_u8(i);
     }

     #[inline]
     fn write_u16(&mut self, i: u16) {
         self.hasher.write_u16(i);
     }

     #[inline]
     fn write_u32(&mut self, i: u32) {
         self.hasher.write_u32(i);
     }

     #[inline]
     fn write_u64(&mut self, i: u64) {
         self.hasher.write_u64(i);
     }
 }

 impl<S: Sip> hash::Hasher for Hasher<S> {
     #[inline]
     fn write_usize(&mut self, i: usize) {
         self.short_write(i, i.to_le() as u64);
     }

     #[inline]
     fn write_u8(&mut self, i: u8) {
         self.short_write(i, i as u64);
     }

     #[inline]
     fn write_u32(&mut self, i: u32) {
         self.short_write(i, i.to_le() as u64);
     }

     #[inline]
     fn write_u64(&mut self, i: u64) {
         self.short_write(i, i.to_le());
     }

     #[inline]
     fn write(&mut self, msg: &[u8]) {
         let length = msg.len();
         self.length += length;

         let mut needed = 0;

         if self.ntail != 0 {
             needed = 8 - self.ntail;
             self.tail |= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << (8 * self.ntail);
             if length < needed {
                 self.ntail += length;
                 return;
             } else {
                 self.state.v3 ^= self.tail;
                 S::c_rounds(&mut self.state);
                 self.state.v0 ^= self.tail;
                 self.ntail = 0;
             }
         }

         // Buffered tail is now flushed, process new input.
         let len = length - needed;
         let left = len & 0x7;

         let mut i = needed;
         while i < len - left {
             let mi = unsafe { load_int_le!(msg, i, u64) };

             self.state.v3 ^= mi;
             S::c_rounds(&mut self.state);
             self.state.v0 ^= mi;

             i += 8;
         }

         self.tail = unsafe { u8to64_le(msg, i, left) };
         self.ntail = left;
     }

     #[inline]
     fn finish(&self) -> u64 {
         let mut state = self.state;

         let b: u64 = ((self.length as u64 & 0xff) << 56) | self.tail;

         state.v3 ^= b;
         S::c_rounds(&mut state);
         state.v0 ^= b;

         state.v2 ^= 0xff;
         S::d_rounds(&mut state);

         state.v0 ^ state.v1 ^ state.v2 ^ state.v3
     }
 }

 impl<S: Sip> Default for Hasher<S> {
     /// Creates a `Hasher<S>` with the two initial keys set to 0.
     #[inline]
     fn default() -> Hasher<S> {
         Hasher::new_with_keys(0, 0)
     }
 }

 #[doc(hidden)]
 trait Sip {
     fn c_rounds(_: &mut State);
     fn d_rounds(_: &mut State);
 }

 #[derive(Debug, Clone, Copy, Default)]
 struct Sip13Rounds;

 impl Sip for Sip13Rounds {
     #[inline]
     fn c_rounds(state: &mut State) {
         compress!(state);
     }

     #[inline]
     fn d_rounds(state: &mut State) {
         compress!(state);
         compress!(state);
         compress!(state);
     }
 }

 #[derive(Debug, Clone, Copy, Default)]
 struct Sip24Rounds;

 impl Sip for Sip24Rounds {
     #[inline]
     fn c_rounds(state: &mut State) {
         compress!(state);
         compress!(state);
     }

     #[inline]
     fn d_rounds(state: &mut State) {
         compress!(state);
         compress!(state);
         compress!(state);
         compress!(state);
     }
 }
	// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
	// file at the top-level directory of this distribution and at
	// http://rust-lang.org/COPYRIGHT.
	//
	// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
	// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
	// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
	// option. This file may not be copied, modified, or distributed
	// except according to those terms.

	//! An implementation of SipHash.

	use core::cmp;
	use core::hash;
	use core::hash::Hasher as _;
	use core::marker::PhantomData;
	use core::mem;
	use core::ptr;
	use core::u64;

	/// An implementation of SipHash 1-3.
	///
	/// See: <https://www.aumasson.jp/siphash/siphash.pdf>
	#[derive(Debug, Clone, Copy, Default)]
	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
	pub struct SipHasher13 {
	hasher: Hasher<Sip13Rounds>,
	}

	/// An implementation of SipHash 2-4.
	///
	/// See: <https://www.aumasson.jp/siphash/siphash.pdf>
	#[derive(Debug, Clone, Copy, Default)]
	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
	pub struct SipHasher24 {
	hasher: Hasher<Sip24Rounds>,
	}

	/// An implementation of SipHash 2-4.
	///
	/// See: <https://www.aumasson.jp/siphash/siphash.pdf>
	///
	/// SipHash is a general-purpose hashing function: it runs at a good
	/// speed (competitive with Spooky and City) and permits strong _keyed_
	/// hashing. This lets you key your hashtables from a strong RNG, such as
	/// [`rand::os::OsRng`](https://doc.rust-lang.org/rand/rand/os/struct.OsRng.html).
	///
	/// Although the SipHash algorithm is considered to be generally strong,
	/// it is not intended for cryptographic purposes. As such, all
	/// cryptographic uses of this implementation are _strongly discouraged_.
	#[derive(Debug, Clone, Copy, Default)]
	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
	pub struct SipHasher(SipHasher24);

	#[derive(Debug, Clone, Copy)]
	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
	struct Hasher<S: Sip> {
	k0: u64,
	k1: u64,
	length: usize, // how many bytes we've processed
	state: State, // hash State
	tail: u64, // unprocessed bytes le
	ntail: usize, // how many bytes in tail are valid
	_marker: PhantomData<S>,
	}

	#[derive(Debug, Clone, Copy)]
	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
	struct State {
	// v0, v2 and v1, v3 show up in pairs in the algorithm,
	// and simd implementations of SipHash will use vectors
	// of v02 and v13. By placing them in this order in the struct,
	// the compiler can pick up on just a few simd optimizations by itself.
	v0: u64,
	v2: u64,
	v1: u64,
	v3: u64,
	}

	macro_rules! compress {
	($state:expr) => {{
	compress!($state.v0, $state.v1, $state.v2, $state.v3)
	}};
	($v0:expr, $v1:expr, $v2:expr, $v3:expr) => {{
	$v0 = $v0.wrapping_add($v1);
	$v1 = $v1.rotate_left(13);
	$v1 ^= $v0;
	$v0 = $v0.rotate_left(32);
	$v2 = $v2.wrapping_add($v3);
	$v3 = $v3.rotate_left(16);
	$v3 ^= $v2;
	$v0 = $v0.wrapping_add($v3);
	$v3 = $v3.rotate_left(21);
	$v3 ^= $v0;
	$v2 = $v2.wrapping_add($v1);
	$v1 = $v1.rotate_left(17);
	$v1 ^= $v2;
	$v2 = $v2.rotate_left(32);
	}};
	}

	/// Loads an integer of the desired type from a byte stream, in LE order. Uses
	/// `copy_nonoverlapping` to let the compiler generate the most efficient way
	/// to load it from a possibly unaligned address.
	///
	/// Unsafe because: unchecked indexing at `i..i+size_of(int_ty)`
	macro_rules! load_int_le {
	($buf:expr, $i:expr, $int_ty:ident) => {{
	debug_assert!($i + mem::size_of::<$int_ty>() <= $buf.len());
	let mut data = 0 as $int_ty;
	ptr::copy_nonoverlapping(
	$buf.as_ptr().add($i),
	&mut data as mut _ as mut u8,
	mem::size_of::<$int_ty>(),
	);
	data.to_le()
	}};
	}

	/// Loads a u64 using up to 7 bytes of a byte slice. It looks clumsy but the
	/// `copy_nonoverlapping` calls that occur (via `load_int_le!`) all have fixed
	/// sizes and avoid calling `memcpy`, which is good for speed.
	///
	/// Unsafe because: unchecked indexing at start..start+len
	#[inline]
	unsafe fn u8to64_le(buf: &[u8], start: usize, len: usize) -> u64 {
	debug_assert!(len < 8);
	let mut i = 0; // current byte index (from LSB) in the output u64
	let mut out = 0;
	if i + 3 < len {
	out = load_int_le!(buf, start + i, u32) as u64;
	i += 4;
	}
	if i + 1 < len {
	out \|= (load_int_le!(buf, start + i, u16) as u64) << (i * 8);
	i += 2
	}
	if i < len {
	out \|= (buf.get_unchecked(start + i) as u64) << (i 8);
	i += 1;
	}
	debug_assert_eq!(i, len);
	out
	}

	impl SipHasher {
	/// Creates a new `SipHasher` with the two initial keys set to 0.
	#[inline]
	pub fn new() -> SipHasher {
	SipHasher::new_with_keys(0, 0)
	}

	/// Creates a `SipHasher` that is keyed off the provided keys.
	#[inline]
	pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher {
	SipHasher(SipHasher24::new_with_keys(key0, key1))
	}

	/// Creates a `SipHasher` from a 16 byte key.
	pub fn new_with_key(key: &[u8; 16]) -> SipHasher {
	let mut b0 = [0u8; 8];
	let mut b1 = [0u8; 8];
	b0.copy_from_slice(&key[0..8]);
	b1.copy_from_slice(&key[8..16]);
	let key0 = u64::from_le_bytes(b0);
	let key1 = u64::from_le_bytes(b1);
	Self::new_with_keys(key0, key1)
	}

	/// Get the keys used by this hasher
	pub fn keys(&self) -> (u64, u64) {
	(self.0.hasher.k0, self.0.hasher.k1)
	}

	/// Get the key used by this hasher as a 16 byte vector
	pub fn key(&self) -> [u8; 16] {
	let mut bytes = [0u8; 16];
	bytes[0..8].copy_from_slice(&self.0.hasher.k0.to_le_bytes());
	bytes[8..16].copy_from_slice(&self.0.hasher.k1.to_le_bytes());
	bytes
	}

	/// Hash a byte array - This is the easiest and safest way to use SipHash.
	#[inline]
	pub fn hash(&self, bytes: &[u8]) -> u64 {
	let mut hasher = self.0.hasher;
	hasher.write(bytes);
	hasher.finish()
	}
	}

	impl SipHasher13 {
	/// Creates a new `SipHasher13` with the two initial keys set to 0.
	#[inline]
	pub fn new() -> SipHasher13 {
	SipHasher13::new_with_keys(0, 0)
	}

	/// Creates a `SipHasher13` that is keyed off the provided keys.
	#[inline]
	pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher13 {
	SipHasher13 {
	hasher: Hasher::new_with_keys(key0, key1),
	}
	}

	/// Creates a `SipHasher13` from a 16 byte key.
	pub fn new_with_key(key: &[u8; 16]) -> SipHasher13 {
	let mut b0 = [0u8; 8];
	let mut b1 = [0u8; 8];
	b0.copy_from_slice(&key[0..8]);
	b1.copy_from_slice(&key[8..16]);
	let key0 = u64::from_le_bytes(b0);
	let key1 = u64::from_le_bytes(b1);
	Self::new_with_keys(key0, key1)
	}

	/// Get the keys used by this hasher
	pub fn keys(&self) -> (u64, u64) {
	(self.hasher.k0, self.hasher.k1)
	}

	/// Get the key used by this hasher as a 16 byte vector
	pub fn key(&self) -> [u8; 16] {
	let mut bytes = [0u8; 16];
	bytes[0..8].copy_from_slice(&self.hasher.k0.to_le_bytes());
	bytes[8..16].copy_from_slice(&self.hasher.k1.to_le_bytes());
	bytes
	}

	/// Hash a byte array - This is the easiest and safest way to use SipHash.
	#[inline]
	pub fn hash(&self, bytes: &[u8]) -> u64 {
	let mut hasher = self.hasher;
	hasher.write(bytes);
	hasher.finish()
	}
	}

	impl SipHasher24 {
	/// Creates a new `SipHasher24` with the two initial keys set to 0.
	#[inline]
	pub fn new() -> SipHasher24 {
	SipHasher24::new_with_keys(0, 0)
	}

	/// Creates a `SipHasher24` that is keyed off the provided keys.
	#[inline]
	pub fn new_with_keys(key0: u64, key1: u64) -> SipHasher24 {
	SipHasher24 {
	hasher: Hasher::new_with_keys(key0, key1),
	}
	}

	/// Creates a `SipHasher24` from a 16 byte key.
	pub fn new_with_key(key: &[u8; 16]) -> SipHasher24 {
	let mut b0 = [0u8; 8];
	let mut b1 = [0u8; 8];
	b0.copy_from_slice(&key[0..8]);
	b1.copy_from_slice(&key[8..16]);
	let key0 = u64::from_le_bytes(b0);
	let key1 = u64::from_le_bytes(b1);
	Self::new_with_keys(key0, key1)
	}

	/// Get the keys used by this hasher
	pub fn keys(&self) -> (u64, u64) {
	(self.hasher.k0, self.hasher.k1)
	}

	/// Get the key used by this hasher as a 16 byte vector
	pub fn key(&self) -> [u8; 16] {
	let mut bytes = [0u8; 16];
	bytes[0..8].copy_from_slice(&self.hasher.k0.to_le_bytes());
	bytes[8..16].copy_from_slice(&self.hasher.k1.to_le_bytes());
	bytes
	}

	/// Hash a byte array - This is the easiest and safest way to use SipHash.
	#[inline]
	pub fn hash(&self, bytes: &[u8]) -> u64 {
	let mut hasher = self.hasher;
	hasher.write(bytes);
	hasher.finish()
	}
	}

	impl<S: Sip> Hasher<S> {
	#[inline]
	fn new_with_keys(key0: u64, key1: u64) -> Hasher<S> {
	let mut state = Hasher {
	k0: key0,
	k1: key1,
	length: 0,
	state: State {
	v0: 0,
	v1: 0,
	v2: 0,
	v3: 0,
	},
	tail: 0,
	ntail: 0,
	_marker: PhantomData,
	};
	state.reset();
	state
	}

	#[inline]
	fn reset(&mut self) {
	self.length = 0;
	self.state.v0 = self.k0 ^ 0x736f6d6570736575;
	self.state.v1 = self.k1 ^ 0x646f72616e646f6d;
	self.state.v2 = self.k0 ^ 0x6c7967656e657261;
	self.state.v3 = self.k1 ^ 0x7465646279746573;
	self.ntail = 0;
	}

	// A specialized write function for values with size <= 8.
	//
	// The hashing of multi-byte integers depends on endianness. E.g.:
	// - little-endian: `write_u32(0xDDCCBBAA)` == `write([0xAA, 0xBB, 0xCC, 0xDD])`
	// - big-endian: `write_u32(0xDDCCBBAA)` == `write([0xDD, 0xCC, 0xBB, 0xAA])`
	//
	// This function does the right thing for little-endian hardware. On
	// big-endian hardware `x` must be byte-swapped first to give the right
	// behaviour. After any byte-swapping, the input must be zero-extended to
	// 64-bits. The caller is responsible for the byte-swapping and
	// zero-extension.
	#[inline]
	fn short_write<T>(&mut self, _x: T, x: u64) {
	let size = mem::size_of::<T>();
	self.length += size;

	// The original number must be zero-extended, not sign-extended.
	debug_assert!(if size < 8 { x >> (8 * size) == 0 } else { true });

	// The number of bytes needed to fill `self.tail`.
	let needed = 8 - self.ntail;

	self.tail \|= x << (8 * self.ntail);
	if size < needed {
	self.ntail += size;
	return;
	}

	// `self.tail` is full, process it.
	self.state.v3 ^= self.tail;
	S::c_rounds(&mut self.state);
	self.state.v0 ^= self.tail;

	self.ntail = size - needed;
	self.tail = if needed < 8 { x >> (8 * needed) } else { 0 };
	}
	}

	impl hash::Hasher for SipHasher {
	#[inline]
	fn write(&mut self, msg: &[u8]) {
	self.0.write(msg)
	}

	#[inline]
	fn finish(&self) -> u64 {
	self.0.finish()
	}

	#[inline]
	fn write_usize(&mut self, i: usize) {
	self.0.write_usize(i);
	}

	#[inline]
	fn write_u8(&mut self, i: u8) {
	self.0.write_u8(i);
	}

	#[inline]
	fn write_u16(&mut self, i: u16) {
	self.0.write_u16(i);
	}

	#[inline]
	fn write_u32(&mut self, i: u32) {
	self.0.write_u32(i);
	}

	#[inline]
	fn write_u64(&mut self, i: u64) {
	self.0.write_u64(i);
	}
	}

	impl hash::Hasher for SipHasher13 {
	#[inline]
	fn write(&mut self, msg: &[u8]) {
	self.hasher.write(msg)
	}

	#[inline]
	fn finish(&self) -> u64 {
	self.hasher.finish()
	}

	#[inline]
	fn write_usize(&mut self, i: usize) {
	self.hasher.write_usize(i);
	}

	#[inline]
	fn write_u8(&mut self, i: u8) {
	self.hasher.write_u8(i);
	}

	#[inline]
	fn write_u16(&mut self, i: u16) {
	self.hasher.write_u16(i);
	}

	#[inline]
	fn write_u32(&mut self, i: u32) {
	self.hasher.write_u32(i);
	}

	#[inline]
	fn write_u64(&mut self, i: u64) {
	self.hasher.write_u64(i);
	}
	}

	impl hash::Hasher for SipHasher24 {
	#[inline]
	fn write(&mut self, msg: &[u8]) {
	self.hasher.write(msg)
	}

	#[inline]
	fn finish(&self) -> u64 {
	self.hasher.finish()
	}

	#[inline]
	fn write_usize(&mut self, i: usize) {
	self.hasher.write_usize(i);
	}

	#[inline]
	fn write_u8(&mut self, i: u8) {
	self.hasher.write_u8(i);
	}

	#[inline]
	fn write_u16(&mut self, i: u16) {
	self.hasher.write_u16(i);
	}

	#[inline]
	fn write_u32(&mut self, i: u32) {
	self.hasher.write_u32(i);
	}

	#[inline]
	fn write_u64(&mut self, i: u64) {
	self.hasher.write_u64(i);
	}
	}

	impl<S: Sip> hash::Hasher for Hasher<S> {
	#[inline]
	fn write_usize(&mut self, i: usize) {
	self.short_write(i, i.to_le() as u64);
	}

	#[inline]
	fn write_u8(&mut self, i: u8) {
	self.short_write(i, i as u64);
	}

	#[inline]
	fn write_u32(&mut self, i: u32) {
	self.short_write(i, i.to_le() as u64);
	}

	#[inline]
	fn write_u64(&mut self, i: u64) {
	self.short_write(i, i.to_le());
	}

	#[inline]
	fn write(&mut self, msg: &[u8]) {
	let length = msg.len();
	self.length += length;

	let mut needed = 0;

	if self.ntail != 0 {
	needed = 8 - self.ntail;
	self.tail \|= unsafe { u8to64_le(msg, 0, cmp::min(length, needed)) } << (8 * self.ntail);
	if length < needed {
	self.ntail += length;
	return;
	} else {
	self.state.v3 ^= self.tail;
	S::c_rounds(&mut self.state);
	self.state.v0 ^= self.tail;
	self.ntail = 0;
	}
	}

	// Buffered tail is now flushed, process new input.
	let len = length - needed;
	let left = len & 0x7;

	let mut i = needed;
	while i < len - left {
	let mi = unsafe { load_int_le!(msg, i, u64) };

	self.state.v3 ^= mi;
	S::c_rounds(&mut self.state);
	self.state.v0 ^= mi;

	i += 8;
	}

	self.tail = unsafe { u8to64_le(msg, i, left) };
	self.ntail = left;
	}

	#[inline]
	fn finish(&self) -> u64 {
	let mut state = self.state;

	let b: u64 = ((self.length as u64 & 0xff) << 56) \| self.tail;

	state.v3 ^= b;
	S::c_rounds(&mut state);
	state.v0 ^= b;

	state.v2 ^= 0xff;
	S::d_rounds(&mut state);

	state.v0 ^ state.v1 ^ state.v2 ^ state.v3
	}
	}

	impl<S: Sip> Default for Hasher<S> {
	/// Creates a `Hasher<S>` with the two initial keys set to 0.
	#[inline]
	fn default() -> Hasher<S> {
	Hasher::new_with_keys(0, 0)
	}
	}

	#[doc(hidden)]
	trait Sip {
	fn c_rounds(_: &mut State);
	fn d_rounds(_: &mut State);
	}

	#[derive(Debug, Clone, Copy, Default)]
	struct Sip13Rounds;

	impl Sip for Sip13Rounds {
	#[inline]
	fn c_rounds(state: &mut State) {
	compress!(state);
	}

	#[inline]
	fn d_rounds(state: &mut State) {
	compress!(state);
	compress!(state);
	compress!(state);
	}
	}

	#[derive(Debug, Clone, Copy, Default)]
	struct Sip24Rounds;

	impl Sip for Sip24Rounds {
	#[inline]
	fn c_rounds(state: &mut State) {
	compress!(state);
	compress!(state);
	}

	#[inline]
	fn d_rounds(state: &mut State) {
	compress!(state);
	compress!(state);
	compress!(state);
	compress!(state);
	}
	}