remove the redundant hasher in Bloom

util/bloom/src/lib.rs

@@ -24,9 +24,6 @@ use std::hash::{Hash, Hasher};
 use std::collections::HashSet;
 use siphasher::sip::SipHasher;
 
-// TODO [ToDr] Both hashers are exactly the same - no point to keep two.
-const NUMBER_OF_HASHERS: usize = 2;
-
 /// BitVec structure with journalling
 /// Every time any of the blocks is getting set it's index is tracked
 /// and can be then drained by `drain` method
@@ -80,8 +77,7 @@ pub struct Bloom {
 	bitmap: BitVecJournal,
 	bitmap_bits: u64,
 	k_num: u32,
-	// TODO [ToDr] Both hashers are exactly the same - no point to keep two.
-	sips: [SipHasher; NUMBER_OF_HASHERS],
+	sip: SipHasher,
 }
 
 impl Bloom {
@@ -93,12 +89,12 @@ impl Bloom {
 		let bitmap_bits = (bitmap_size as u64) * 8u64;
 		let k_num = Bloom::optimal_k_num(bitmap_bits, items_count);
 		let bitmap = BitVecJournal::new(bitmap_bits as usize);
-		let sips = [SipHasher::new(), SipHasher::new()];
+		let sip = SipHasher::new();
 		Bloom {
 			bitmap: bitmap,
 			bitmap_bits: bitmap_bits,
 			k_num: k_num,
-			sips: sips,
+			sip: sip,
 		}
 	}
 
@@ -107,12 +103,12 @@ impl Bloom {
 		let bitmap_size = parts.len() * 8;
 		let bitmap_bits = (bitmap_size as u64) * 8u64;
 		let bitmap = BitVecJournal::from_parts(parts);
-		let sips = [SipHasher::new(), SipHasher::new()];
+		let sip = SipHasher::new();
 		Bloom {
 			bitmap: bitmap,
 			bitmap_bits: bitmap_bits,
 			k_num: k_num,
-			sips: sips,
+			sip: sip,
 		}
 	}
 
@@ -178,11 +174,11 @@ impl Bloom {
 		cmp::max(k_num, 1)
 	}
 
-	fn bloom_hash<T>(&self, hashes: &mut [u64; NUMBER_OF_HASHERS], item: &T, k_i: u32) -> u64
+	fn bloom_hash<T>(&self, hashes: &mut [u64; 2], item: &T, k_i: u32) -> u64
 		where T: Hash
 	{
-		if k_i < NUMBER_OF_HASHERS as u32 {
-			let mut sip = self.sips[k_i as usize].clone();
+		if k_i < 2 {
+			let mut sip = self.sip.clone();
 			item.hash(&mut sip);
 			let hash = sip.finish();
 			hashes[k_i as usize] = hash;