convert: use unsafe string <-> []byte conversions

internal/proto/hotstuffpb/convert.go

@@ -2,6 +2,8 @@ package hotstuffpb
 
 import (
  "math/big"
+ "reflect"
+ "unsafe"
 
  "github.com/relab/hotstuff"
  "github.com/relab/hotstuff/crypto"
@@ -116,7 +118,7 @@ func BlockToProto(block *hotstuff.Block) *Block {
  parentHash := block.Parent()
  return &Block{
  Parent: parentHash[:],
- Command: []byte(block.Command()),
+ Command: unsafeStringToBytes(block.Command()),
  QC: QuorumCertToProto(block.QuorumCert()),
  View: uint64(block.View()),
  Proposer: uint32(block.Proposer()),
@@ -130,7 +132,7 @@ func BlockFromProto(block *Block) *hotstuff.Block {
  return hotstuff.NewBlock(
  p,
  QuorumCertFromProto(block.GetQC()),
- hotstuff.Command(block.GetCommand()),
+ unsafeBytesToString(block.GetCommand()),
  hotstuff.View(block.GetView()),
  hotstuff.ID(block.GetProposer()),
  )
@@ -222,3 +224,18 @@ func SyncInfoToProto(syncInfo hotstuff.SyncInfo) *SyncInfo {
  }
  return m
 }
+
+func unsafeStringToBytes(s string) []byte {
+ if s == "" {
+ return []byte{}
+ }
+ const max = 0x7fff0000
+ if len(s) > max {
+ panic("string too long")
+ }
+ return (*[max]byte)(unsafe.Pointer((*reflect.StringHeader)(unsafe.Pointer(&s)).Data))[:len(s):len(s)]
+}
+
+func unsafeBytesToString(b []byte) string {
+ return *(*string)(unsafe.Pointer(&b))
+}