Merge 8e61afff2d into af28d12847

consensus/ethash/algorithm.go

@@ -18,7 +18,6 @@ package ethash
 
 import (
 	"encoding/binary"
-	"hash"
 	"math/big"
 	"reflect"
 	"runtime"
@@ -94,17 +93,6 @@ func calcDatasetSize(epoch int) uint64 {
 // reused between hash runs instead of requiring new ones to be created.
 type hasher func(dest []byte, data []byte)
 
-// makeHasher creates a repetitive hasher, allowing the same hash data structures
-// to be reused between hash runs instead of requiring new ones to be created.
-// The returned function is not thread safe!
-func makeHasher(h hash.Hash) hasher {
-	return func(dest []byte, data []byte) {
-		h.Write(data)
-		h.Sum(dest[:0])
-		h.Reset()
-	}
-}
-
 // seedHash is the seed to use for generating a verification cache and the mining
 // dataset.
 func seedHash(block uint64) []byte {
@@ -112,7 +100,7 @@ func seedHash(block uint64) []byte {
 	if block < epochLength {
 		return seed
 	}
-	keccak256 := makeHasher(sha3.NewKeccak256())
+	keccak256 := sha3.KeccakFast256
 	for i := 0; i < int(block/epochLength); i++ {
 		keccak256(seed, seed)
 	}
@@ -166,7 +154,7 @@ func generateCache(dest []uint32, epoch uint64, seed []byte) {
 		}
 	}()
 	// Create a hasher to reuse between invocations
-	keccak512 := makeHasher(sha3.NewKeccak512())
+	keccak512 := sha3.KeccakFast512
 
 	// Sequentially produce the initial dataset
 	keccak512(cache, seed)
@@ -299,7 +287,7 @@ func generateDataset(dest []uint32, epoch uint64, cache []uint32) {
 			defer pend.Done()
 
 			// Create a hasher to reuse between invocations
-			keccak512 := makeHasher(sha3.NewKeccak512())
+			keccak512 := sha3.KeccakFast512
 
 			// Calculate the data segment this thread should generate
 			batch := uint32((size + hashBytes*uint64(threads) - 1) / (hashBytes * uint64(threads)))
@@ -373,7 +361,7 @@ func hashimoto(hash []byte, nonce uint64, size uint64, lookup func(index uint32)
 // in-memory cache) in order to produce our final value for a particular header
 // hash and nonce.
 func hashimotoLight(size uint64, cache []uint32, hash []byte, nonce uint64) ([]byte, []byte) {
-	keccak512 := makeHasher(sha3.NewKeccak512())
+	keccak512 := sha3.KeccakFast512
 
 	lookup := func(index uint32) []uint32 {
 		rawData := generateDatasetItem(cache, index, keccak512)

crypto/sha3/sha3.go

@@ -4,6 +4,8 @@
 
 package sha3
 
+import "encoding/binary"
+
 // spongeDirection indicates the direction bytes are flowing through the sponge.
 type spongeDirection int
 
@@ -190,3 +192,60 @@ func (d *state) Sum(in []byte) []byte {
 	dup.Read(hash)
 	return append(in, hash...)
 }
+
+
+
+func keccakFast(out []byte, bits int, data []byte) {
+	const wordSize = 8
+	hashSize := bits / 8
+	blockSize := (1600 - bits * 2) / 8
+
+	var state [25]uint64
+
+	dataIndex := 0
+
+	dataLen := len(data)
+	for dataLen >= blockSize {
+		for i := 0; i < (blockSize / wordSize); i++ {
+			state[i] ^= binary.LittleEndian.Uint64(data[dataIndex:])
+			dataIndex += wordSize
+		}
+		keccakF1600(&state)
+		dataLen -= blockSize
+	}
+
+	stateIndex := 0
+	for dataLen >= wordSize {
+		state[stateIndex] ^= binary.LittleEndian.Uint64(data[dataIndex:])
+		stateIndex++
+		dataIndex += wordSize
+		dataLen -= wordSize
+	}
+
+	var lastWord [8]byte
+	lastWordIndex := 0
+	for dataLen > 0 {
+		lastWord[lastWordIndex] = data[dataIndex]
+		lastWordIndex++
+		dataIndex++
+		dataLen--
+	}
+	lastWord[lastWordIndex] = 0x01
+	state[stateIndex] ^= binary.LittleEndian.Uint64(lastWord[:])
+
+	state[(blockSize/wordSize) - 1] ^= 0x8000000000000000
+
+	keccakF1600(&state)
+
+	for i := 0; i < (hashSize / wordSize); i++ {
+		binary.LittleEndian.PutUint64(out[i * 8:], state[i])
+	}
+}
+
+func KeccakFast256(dest []byte, data []byte) {
+	keccakFast(dest, 256, data)
+}
+
+func KeccakFast512(dest []byte, data []byte) {
+	keccakFast(dest, 512, data)
+}