Initial commit

lib/wal/wal-header.go

@@ -0,0 +1,25 @@
+package wal
+
+import "encoding/binary"
+
+type walHeader struct {
+	FirstSegmentID int64
+	LastSegmentID  int64
+}
+
+func (h walHeader) WriteTo(b []byte) {
+	vals := []int64{h.FirstSegmentID, h.LastSegmentID}
+
+	for _, val := range vals {
+		binary.LittleEndian.PutUint64(b[0:8], uint64(val))
+		b = b[8:]
+	}
+}
+
+func (h *walHeader) ReadFrom(b []byte) {
+	ptrs := []*int64{&h.FirstSegmentID, &h.LastSegmentID}
+	for _, ptr := range ptrs {
+		*ptr = int64(binary.LittleEndian.Uint64(b[0:8]))
+		b = b[8:]
+	}
+}