Itertools are no longer reexported from util, optimized triedb iter

util/src/journaldb/earlymergedb.rs

@@ -21,7 +21,6 @@ use std::collections::HashMap;
 use std::sync::Arc;
 use parking_lot::RwLock;
 use heapsize::HeapSizeOf;
-use itertools::Itertools;
 use rlp::*;
 use hashdb::*;
 use memorydb::*;
@@ -432,7 +431,9 @@ impl JournalDB for EarlyMergeDB {
 			// - we write the key into our journal for this block;
 
 			r.begin_list(inserts.len());
-			inserts.iter().foreach(|&(k, _)| {r.append(&k);});
+			for &(k, _) in &inserts {
+				r.append(&k);
+			}
 			r.append_list(&removes);
 			Self::insert_keys(&inserts, &*self.backing, self.column, &mut refs, batch, trace);
 

util/src/lib.rs

@@ -106,7 +106,6 @@ extern crate rlp;
 extern crate regex;
 extern crate lru_cache;
 extern crate heapsize;
-extern crate itertools;
 extern crate ethcore_logger;
 
 #[macro_use]
@@ -153,7 +152,6 @@ pub use bigint::hash;
 
 pub use ansi_term::{Colour, Style};
 pub use heapsize::HeapSizeOf;
-pub use itertools::Itertools;
 pub use parking_lot::{Condvar, Mutex, MutexGuard, RwLock, RwLockReadGuard, RwLockWriteGuard};
 
 /// 160-bit integer representing account address

util/src/trie/triedb.rs

@@ -15,7 +15,6 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 use std::fmt;
-use itertools::Itertools;
 use hashdb::*;
 use nibbleslice::*;
 use rlp::*;
@@ -293,7 +292,18 @@ impl<'a> TrieDBIterator<'a> {
 	/// The present key.
 	fn key(&self) -> Bytes {
 		// collapse the key_nibbles down to bytes.
-		self.key_nibbles.iter().step(2).zip(self.key_nibbles.iter().skip(1).step(2)).map(|(h, l)| h * 16 + l).collect()
+		unsafe {
+			let size = self.key_nibbles.len() / 2;
+			let mut ptr = self.key_nibbles.as_ptr();
+			let mut result = Bytes::with_capacity(size);
+
+			for _ in 0..size {
+				result.push(*ptr * 16 + *ptr.offset(1));
+				ptr = ptr.offset(2);
+			}
+
+			result
+		}
 	}
 }