From 0b22ad99c18b6aaa77afc32113c308f12a07e843 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Thu, 25 Jun 2015 14:46:44 +0200
Subject: [PATCH] core: optimize IntrinsicGas

---
 core/state_transition.go | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/core/state_transition.go b/core/state_transition.go
index 2c8770cbe5..5844ad3c8a 100644
--- a/core/state_transition.go
+++ b/core/state_transition.go
@@ -77,12 +77,19 @@ func MessageGasValue(msg Message) *big.Int {
 // with the given data.
 func IntrinsicGas(data []byte) *big.Int {
 	igas := new(big.Int).Set(params.TxGas)
-	for _, byt := range data {
-		if byt != 0 {
-			igas.Add(igas, params.TxDataNonZeroGas)
-		} else {
-			igas.Add(igas, params.TxDataZeroGas)
+	if len(data) > 0 {
+		var nz int64
+		for _, byt := range data {
+			if byt != 0 {
+				nz++
+			}
 		}
+		m := big.NewInt(nz)
+		m.Mul(m, params.TxDataNonZeroGas)
+		igas.Add(igas, m)
+		m.SetInt64(int64(len(data)) - nz)
+		m.Mul(m, params.TxDataZeroGas)
+		igas.Add(igas, m)
 	}
 	return igas
 }