diff options
| -rw-r--r-- | consensus/ethash/algorithm.go | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/consensus/ethash/algorithm.go b/consensus/ethash/algorithm.go index 905a7b1ea..fa1c2c824 100644 --- a/consensus/ethash/algorithm.go +++ b/consensus/ethash/algorithm.go @@ -94,14 +94,25 @@ 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! +// 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 { + // sha3.state supports Read to get the sum, use it to avoid the overhead of Sum. + // Read alters the state but we reset the hash before every operation. + type readerHash interface { + hash.Hash + Read([]byte) (int, error) + } + rh, ok := h.(readerHash) + if !ok { + panic("can't find Read method on hash") + } + outputLen := rh.Size() return func(dest []byte, data []byte) { - h.Write(data) - h.Sum(dest[:0]) - h.Reset() + rh.Reset() + rh.Write(data) + rh.Read(dest[:outputLen]) } } |