1 files changed, 161 insertions, 0 deletions
diff --git a/vendor/github.com/dexon-foundation/dexon-consensus/core/utils.go b/vendor/github.com/dexon-foundation/dexon-consensus/core/utils.go
new file mode 100644
index 000000000..6b9ce634f
--- /dev/null
+++ b/vendor/github.com/dexon-foundation/dexon-consensus/core/utils.go
@@ -0,0 +1,161 @@
+// Copyright 2018 The dexon-consensus Authors
+// This file is part of the dexon-consensus library.
+//
+// The dexon-consensus library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"sort"
+	"time"
+
+	"github.com/dexon-foundation/dexon-consensus/common"
+	"github.com/dexon-foundation/dexon-consensus/core/crypto"
+	"github.com/dexon-foundation/dexon-consensus/core/types"
+)
+
+var (
+	debug = false
+	// ErrEmptyTimestamps would be reported if Block.timestamps is empty.
+	ErrEmptyTimestamps = errors.New("timestamp vector should not be empty")
+)
+
+func init() {
+	if os.Getenv("DEBUG") != "" {
+		debug = true
+	}
+}
+
+// Debugf is like fmt.Printf, but only output when we are in debug mode.
+func Debugf(format string, args ...interface{}) {
+	if debug {
+		fmt.Printf(format, args...)
+	}
+}
+
+// Debugln is like fmt.Println, but only output when we are in debug mode.
+func Debugln(args ...interface{}) {
+	if debug {
+		fmt.Println(args)
+	}
+}
+
+func interpoTime(t1 time.Time, t2 time.Time, sep int) []time.Time {
+	if sep == 0 {
+		return []time.Time{}
+	}
+	if t1.After(t2) {
+		return interpoTime(t2, t1, sep)
+	}
+	timestamps := make([]time.Time, sep)
+	duration := t2.Sub(t1)
+	period := time.Duration(
+		(duration.Nanoseconds() / int64(sep+1))) * time.Nanosecond
+	prevTime := t1
+	for idx := range timestamps {
+		prevTime = prevTime.Add(period)
+		timestamps[idx] = prevTime
+	}
+	return timestamps
+}
+
+func getMedianTime(timestamps []time.Time) (t time.Time, err error) {
+	if len(timestamps) == 0 {
+		err = ErrEmptyTimestamps
+		return
+	}
+	tscopy := make([]time.Time, 0, len(timestamps))
+	for _, ts := range timestamps {
+		tscopy = append(tscopy, ts)
+	}
+	sort.Sort(common.ByTime(tscopy))
+	if len(tscopy)%2 == 0 {
+		t1 := tscopy[len(tscopy)/2-1]
+		t2 := tscopy[len(tscopy)/2]
+		t = interpoTime(t1, t2, 1)[0]
+	} else {
+		t = tscopy[len(tscopy)/2]
+	}
+	return
+}
+
+func removeFromSortedUint32Slice(xs []uint32, x uint32) []uint32 {
+	indexToRemove := sort.Search(len(xs), func(idx int) bool {
+		return xs[idx] >= x
+	})
+	if indexToRemove == len(xs) || xs[indexToRemove] != x {
+		// This value is not found.
+		return xs
+	}
+	return append(xs[:indexToRemove], xs[indexToRemove+1:]...)
+}
+
+// HashConfigurationBlock returns the hash value of configuration block.
+func HashConfigurationBlock(
+	notarySet map[types.NodeID]struct{},
+	config *types.Config,
+	snapshotHash common.Hash,
+	prevHash common.Hash,
+) common.Hash {
+	notaryIDs := make(types.NodeIDs, 0, len(notarySet))
+	for nID := range notarySet {
+		notaryIDs = append(notaryIDs, nID)
+	}
+	sort.Sort(notaryIDs)
+	notarySetBytes := make([]byte, 0, len(notarySet)*len(common.Hash{}))
+	for _, nID := range notaryIDs {
+		notarySetBytes = append(notarySetBytes, nID.Hash[:]...)
+	}
+	configBytes := config.Bytes()
+
+	return crypto.Keccak256Hash(
+		notarySetBytes[:],
+		configBytes[:],
+		snapshotHash[:],
+		prevHash[:],
+	)
+}
+
+// VerifyBlock verifies the signature of types.Block.
+func VerifyBlock(b *types.Block) (err error) {
+	hash, err := hashBlock(b)
+	if err != nil {
+		return
+	}
+	if hash != b.Hash {
+		err = ErrIncorrectHash
+		return
+	}
+	pubKey, err := crypto.SigToPub(b.Hash, b.Signature)
+	if err != nil {
+		return
+	}
+	if !b.ProposerID.Equal(types.NewNodeID(pubKey)) {
+		err = ErrIncorrectSignature
+		return
+	}
+	return
+}
+
+// DiffUint64 calculates difference between two uint64.
+func DiffUint64(a, b uint64) uint64 {
+	if a > b {
+		return a - b
+	}
+	return b - a
+}