Forward port blake2 storage support (#2360)

* move storage maps to blake2_128 (#2268)

* remove default hash, introduce twox_128 and blake2

* use blake2_128 & create ext_blake2_128

* refactor code

* add benchmark

* factorize generator

* fix

* parameterizable hasher

* some fix

* fix

* fix

* fix

* metadata

* fix

* remove debug print

* map -> blake2_256

* fix test

* fix test

* Apply suggestions from code review

Co-Authored-By: thiolliere <gui.thiolliere@gmail.com>

* impl twox 128 concat (#2353)

* impl twox_128_concat

* comment addressed

* fix

* impl twox_128->64_concat

* fix test

* Fix compilation and cleanup some docs

* Apply suggestions from code review

Co-Authored-By: bkchr <bkchr@users.noreply.github.com>

substrate/core/primitives/src/hashing.rs

@@ -55,6 +55,23 @@ pub fn blake2_128(data: &[u8]) -> [u8; 16] {
 	r
 }
 
+/// Do a XX 64-bit hash and place result in `dest`.
+pub fn twox_64_into(data: &[u8], dest: &mut [u8; 8]) {
+	use ::core::hash::Hasher;
+	let mut h0 = twox_hash::XxHash::with_seed(0);
+	h0.write(data);
+	let r0 = h0.finish();
+	use byteorder::{ByteOrder, LittleEndian};
+	LittleEndian::write_u64(&mut dest[0..8], r0);
+}
+
+/// Do a XX 64-bit hash and return result.
+pub fn twox_64(data: &[u8]) -> [u8; 8] {
+	let mut r: [u8; 8] = [0; 8];
+	twox_64_into(data, &mut r);
+	r
+}
+
 /// Do a XX 128-bit hash and place result in `dest`.
 pub fn twox_128_into(data: &[u8], dest: &mut [u8; 16]) {
 	use ::core::hash::Hasher;

substrate/core/primitives/src/lib.rs

@@ -46,7 +46,7 @@ pub use impl_serde::serialize as bytes;
 #[cfg(feature = "std")]
 pub mod hashing;
 #[cfg(feature = "std")]
-pub use hashing::{blake2_256, twox_128, twox_256};
+pub use hashing::{blake2_128, blake2_256, twox_64, twox_128, twox_256};
 #[cfg(feature = "std")]
 pub mod hexdisplay;
 pub mod crypto;