Revert "Remove nonsensical code"

This reverts commit 233de565af.

go-pool/stratum/miner.go

@@ -178,7 +178,7 @@ func (m *Miner) processShare(s *StratumServer, e *Endpoint, job *Job, t *BlockTe
 			if len(convertedBlob) == 0 {
 				convertedBlob = cnutil.ConvertBlob(shareBuff)
 			}
-			blockFastHash := hex.EncodeToString(hashing.Hash(convertedBlob, true))
+			blockFastHash := hex.EncodeToString(hashing.FastHash(convertedBlob))
 			now := util.MakeTimestamp()
 			roundShares := atomic.SwapInt64(&s.roundShares, 0)
 			ratio := float64(roundShares) / float64(t.difficulty)

hashing/hashing.go

@@ -17,3 +17,7 @@ func Hash(blob []byte, fast bool) []byte {
 	}
 	return output
 }
+
+func FastHash(blob []byte) []byte {
+	return Hash(append([]byte{byte(len(blob))}, blob...), true)
+}

hashing/hashing_test.go

@@ -30,6 +30,19 @@ func TestHash_fast(t *testing.T) {
 	}
 }
 
+func TestFastHash(t *testing.T) {
+	blob, _ := hex.DecodeString("01009091e4aa05ff5fe4801727ed0c1b8b339e1a0054d75568fec6ba9c4346e88b10d59edbf6858b2b00008a63b2865b65b84d28bb31feb057b16a21e2eda4bf6cc6377e3310af04debe4a01")
+	hashBytes := FastHash(blob)
+	hash := hex.EncodeToString(hashBytes)
+	log.Println(hash)
+
+	expectedHash := "8706c697d9fc8a48b14ea93a31c6f0750c48683e585ec1a534e9c57c97193fa6"
+
+	if hash != expectedHash {
+		t.Error("Invalid fast hash")
+	}
+}
+
 func BenchmarkHash(b *testing.B) {
 	blob, _ := hex.DecodeString("0100b69bb3aa050a3106491f858f8646d3a8d13fd9924403bf07af95e6e7cc9e4ad105d76da27241565555866b1baa9db8f027cf57cd45d6835c11287b210d9ddb407deda565f8112e19e501")
 	b.ResetTimer()
@@ -58,3 +71,12 @@ func BenchmarkHash_fast(b *testing.B) {
 		Hash(blob, true)
 	}
 }
+
+func BenchmarkFastHash(b *testing.B) {
+	blob, _ := hex.DecodeString("0100b69bb3aa050a3106491f858f8646d3a8d13fd9924403bf07af95e6e7cc9e4ad105d76da27241565555866b1baa9db8f027cf57cd45d6835c11287b210d9ddb407deda565f8112e19e501")
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		FastHash(blob)
+	}
+}