From a8936d92a5a9e8c33da7ea9642f90416265bad2a Mon Sep 17 00:00:00 2001
From: adman <adman.else@gmail.com>
Date: Sun, 10 May 2026 18:41:04 +0200
Subject: [PATCH] add replay reader and writer for handling tmcpr files

---
 cmd/strom/print_replay/main.go |  3 +-
 proto/replay/reader.go         | 67 ++++++++++++++++++++++++++++++++++
 proto/replay/writer.go         | 39 ++++++++++++++++++++
 3 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 proto/replay/reader.go
 create mode 100644 proto/replay/writer.go

diff --git a/cmd/strom/print_replay/main.go b/cmd/strom/print_replay/main.go
index 39379bd..8700fba 100644
--- a/cmd/strom/print_replay/main.go
+++ b/cmd/strom/print_replay/main.go
@@ -82,7 +82,7 @@ func UnpackPacket(r io.Reader) (packet proto_base.EncodeDecodeAble, err error) {
 
 	// Calculate position after reading the packet ID
 	// indexafterid represents how many bytes we've read so far
-	indexafterid := int(b.Size()) - int(b.Len())
+	indexafterid := int(b.Size()) - b.Len()
 
 	i, ok := proto.LookUpTypeByPacketInfo(proto_base.ToClient, state, packetId, int32(*ProtocolVersion))
 	if !ok {
@@ -103,6 +103,7 @@ func UnpackPacket(r io.Reader) (packet proto_base.EncodeDecodeAble, err error) {
 	}
 	return
 }
+
 func Run(args []string) (err error) {
 	err = cmd.Parse(args)
 	if err != nil {
diff --git a/proto/replay/reader.go b/proto/replay/reader.go
new file mode 100644
index 0000000..4409230
--- /dev/null
+++ b/proto/replay/reader.go
@@ -0,0 +1,67 @@
+package replay
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"reflect"
+
+	"github.com/admin-else/strom/proto"
+	"github.com/admin-else/strom/proto_base"
+)
+
+type Reader struct {
+	r       io.Reader
+	State   proto_base.State
+	Version int32
+}
+
+func NewReader(r io.Reader) *Reader {
+	return &Reader{r: r}
+}
+
+func (r *Reader) ReadRaw() (packetData []byte, timestamp, length uint32, err error) {
+	err = binary.Read(r.r, binary.BigEndian, &timestamp)
+	if err != nil {
+		return
+	}
+	err = binary.Read(r.r, binary.BigEndian, &length)
+	if err != nil {
+		return
+	}
+
+	// Read the packet data into a byte slice
+	packetData = make([]byte, length)
+	_, err = io.ReadFull(r.r, packetData)
+	return
+}
+
+func (r *Reader) ReadPacket() (packet proto_base.EncodeDecodeAble, err error) {
+	packetData, _, _, err := r.ReadRaw()
+	if err != nil {
+		return
+	}
+	b := bytes.NewReader(packetData)
+
+	packetId, err := proto_base.DecodeVarInt(b)
+	if err != nil {
+		return
+	}
+
+	// Calculate position after reading the packet ID
+	// indexafterid represents how many bytes we've read so far
+	indexafterid := int(b.Size()) - b.Len()
+
+	i, ok := proto.LookUpTypeByPacketInfo(proto_base.ToClient, r.State, packetId, r.Version)
+	if !ok {
+		packet = &proto.UnCodablePacket{Err: proto.BadPacketIdErr, Data: packetData, Info: i}
+		return
+	}
+	packet = reflect.New(reflect.TypeOf(i.Type).Elem()).Interface().(proto_base.EncodeDecodeAble)
+	err = packet.Decode(b)
+	if err != nil {
+		packet = &proto.UnCodablePacket{Err: err, Data: packetData[indexafterid:], Info: i}
+		return
+	}
+	return
+}
diff --git a/proto/replay/writer.go b/proto/replay/writer.go
new file mode 100644
index 0000000..805ddd5
--- /dev/null
+++ b/proto/replay/writer.go
@@ -0,0 +1,39 @@
+package replay
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+
+	"github.com/admin-else/strom/proto_base"
+)
+
+type Writer struct {
+	w io.Writer
+}
+
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{w}
+}
+
+func (w *Writer) WriteRaw(p []byte, timestamp uint32) (err error) {
+	err = binary.Write(w.w, binary.BigEndian, timestamp)
+	if err != nil {
+		return
+	}
+	err = binary.Write(w.w, binary.BigEndian, uint32(len(p)))
+	if err != nil {
+		return
+	}
+	_, err = w.w.Write(p)
+	return
+}
+
+func (w *Writer) WritePacket(packet proto_base.EncodeDecodeAble, timestamp uint32) (err error) {
+	b := bytes.NewBuffer(nil)
+	err = packet.Encode(b)
+	if err != nil {
+		return
+	}
+	return w.WriteRaw(b.Bytes(), timestamp)
+}