Support different trie radix

.travis.yml

@@ -11,6 +11,4 @@ matrix:
 script:
   - cargo check --all --tests --benches
   - cargo test --all
-  - cd trie-db && cargo check --no-default-features && cd ..
-  - cd memory-db && cargo check --no-default-features && cd ..
-  - cd trie-root && cargo check --no-default-features && cd ..
+  - cd check_no_std && cargo check --no-default-features && cd ..

Cargo.toml

@@ -8,5 +8,6 @@ members = [
 	"test-support/trie-standardmap",
 	"test-support/trie-bench",
 	"trie-db",
-	"trie-root"
+	"trie-root",
+	"check_no_std"
 ]

check_no_std/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "check_no_std"
+version = "0.0.1"
+authors = ["Parity Technologies <[email protected]>"]
+description = "Crate that import dependency as no std for runing cargo check"
+repository = "https://github.com/paritytech/trie"
+license = "Apache-2.0"
+edition = "2018"
+
+[dependencies]
+trie-db = { path = "../trie-db", default-features = false, version = "0.20.1"}
+memory-db = { path = "../memory-db", default-features = false, version = "0.20.1"}
+trie-root = { path = "../trie-root", default-features = false, version = "0.16.0"}

check_no_std/src/lib.rs

@@ -0,0 +1,24 @@
+// Copyright 2017, 2018 Parity Technologies
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Crate to cargo check no std compatible library
+//! without leaking dev-dependencies.
+//! Do not publish.
+
+#![no_std]
+
+
+pub use trie_db::*;
+pub use memory_db::*;
+pub use trie_root::*;

hash-db/src/lib.rs

@@ -40,13 +40,14 @@ impl<T> MaybeDebug for T {}
 /// nibbles (the node key can be split into prefix and node partial).
 /// Therefore it is always the leftmost portion of the node key, so its internal representation
 /// is a non expanded byte slice followed by a last padded byte representation.
-/// The padded byte is an optional padded value.
-pub type Prefix<'a> = (&'a[u8], Option<u8>);
+/// The padded byte is a pair of u8 containing the number of nibble, followed by
+/// the left aligned padded value.
+pub type Prefix<'a> = (&'a[u8], (u8, u8));
 
 /// An empty prefix constant.
 /// Can be use when the prefix is not use internally
 /// or for root nodes.
-pub static EMPTY_PREFIX: Prefix<'static> = (&[], None);
+pub static EMPTY_PREFIX: Prefix<'static> = (&[], (0, 0));
 
 /// Trait describing an object that can hash a slice of bytes. Used to abstract
 /// other types over the hashing algorithm. Defines a single `hash` method and an

memory-db/src/lib.rs

@@ -217,8 +217,8 @@ impl<H: KeyHasher> KeyFunction<H> for PrefixedKey<H> {
 pub fn prefixed_key<H: KeyHasher>(key: &H::Out, prefix: Prefix) -> Vec<u8> {
 	let mut prefixed_key = Vec::with_capacity(key.as_ref().len() + prefix.0.len() + 1);
 	prefixed_key.extend_from_slice(prefix.0);
-	if let Some(last) = prefix.1 {
-		prefixed_key.push(last);
+	if (prefix.1).0 > 0 {
+		prefixed_key.push((prefix.1).1);
 	}
 	prefixed_key.extend_from_slice(key.as_ref());
 	prefixed_key
@@ -243,16 +243,16 @@ impl<H: KeyHasher> KeyFunction<H> for LegacyPrefixedKey<H> {
 /// Only for trie radix 16 trie.
 pub fn legacy_prefixed_key<H: KeyHasher>(key: &H::Out, prefix: Prefix) -> Vec<u8> {
 	let mut prefixed_key = Vec::with_capacity(key.as_ref().len() + prefix.0.len() + 1);
-	if let Some(last) = prefix.1 {
+	if (prefix.1).0 == 0 {
+		prefixed_key.push(0);
+		prefixed_key.extend_from_slice(prefix.0);
+	} else {
 		let mut prev = 0x01u8;
 		for i in prefix.0.iter() {
 			prefixed_key.push((prev << 4) + (*i >> 4));
 			prev = *i;
 		}
-		prefixed_key.push((prev << 4) + (last >> 4));
-	} else {
-		prefixed_key.push(0);
-		prefixed_key.extend_from_slice(prefix.0);
+		prefixed_key.push((prev << 4) + ((prefix.1).1 >> 4));
 	}
 	prefixed_key.extend_from_slice(key.as_ref());
 	prefixed_key