InputStream: add method Rewind()

src/InputStream.cxx

@@ -27,6 +27,7 @@
 #include "util/Domain.hxx"
 
 #include <assert.h>
+#include <stdio.h> /* for SEEK_SET */
 
 static constexpr Domain input_domain("input");
 
@@ -113,6 +114,18 @@ input_stream::LockSeek(offset_type _offset, int whence, Error &error)
 	return Seek(_offset, whence, error);
 }
 
+bool
+input_stream::Rewind(Error &error)
+{
+	return Seek(0, SEEK_SET, error);
+}
+
+bool
+input_stream::LockRewind(Error &error)
+{
+	return LockSeek(0, SEEK_SET, error);
+}
+
 Tag *
 input_stream::ReadTag()
 {