Proper hash ordering, from consensus

p2pool/sidechain/sidechain.go

@@ -329,7 +329,7 @@ func (c *SideChain) verifyBlock(block *PoolBlock) (verification error, invalid e
 			if i == 0 {
 				continue
 			}
-			if bytes.Compare(block.Side.Uncles[i-1][:], uncleId[:]) < 0 {
+			if block.Side.Uncles[i-1].Compare(uncleId) != -1 {
 				return nil, errors.New("invalid uncle order")
 			}
 		}

types/types.go

@@ -5,6 +5,8 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"errors"
+	"runtime"
+	"unsafe"
 )
 
 const HashSize = 32
@@ -38,6 +40,45 @@ func HashFromBytes(buf []byte) (h Hash) {
 	return
 }
 
+// Compare consensus way of comparison
+func (h Hash) Compare(other Hash) int {
+	//golang might free other otherwise
+	defer runtime.KeepAlive(other)
+	defer runtime.KeepAlive(h)
+	a := unsafe.Slice((*uint64)(unsafe.Pointer(&h)), len(h)/int(unsafe.Sizeof(uint64(0))))
+	b := unsafe.Slice((*uint64)(unsafe.Pointer(&other)), len(other)/int(unsafe.Sizeof(uint64(0))))
+
+	if a[3] < b[3] {
+		return -1
+	}
+	if a[3] > b[3] {
+		return 1
+	}
+
+	if a[2] < b[2] {
+		return -1
+	}
+	if a[2] > b[2] {
+		return 1
+	}
+
+	if a[1] < b[1] {
+		return -1
+	}
+	if a[1] > b[1] {
+		return 1
+	}
+
+	if a[0] < b[0] {
+		return -1
+	}
+	if a[0] > b[0] {
+		return 1
+	}
+
+	return 0
+}
+
 func (h Hash) Equals(o Hash) bool {
 	return bytes.Compare(h[:], o[:]) == 0
 }