Add WALHeader & WALFrameHeader

litestream.go

@@ -0,0 +1,19 @@
+package litestream
+
+import (
+	"io"
+)
+
+const (
+	WriteVersionOffset = 18
+	ReadVersionOffset  = 19
+)
+
+// ReadVersion returns the SQLite write & read version.
+// Returns 1 for legacy & 2 for WAL.
+func ReadVersion(b []byte) (writeVersion, readVersion uint8, err error) {
+	if len(b) < ReadVersionOffset {
+		return 0, 0, io.ErrUnexpectedEOF
+	}
+	return b[WriteVersionOffset], b[ReadVersionOffset], nil
+}