--- a/buffer.h	Fri Oct 23 20:53:58 2020 +0800
+++ b/buffer.h	Sat Oct 24 18:56:45 2020 +0800
@@ -49,7 +49,8 @@
 void buf_setlen(buffer* buf, unsigned int len);
 void buf_incrlen(buffer* buf, unsigned int incr);
 void buf_setpos(buffer* buf, unsigned int pos);
-void buf_incrpos(buffer* buf, int incr); /* -ve is ok, to go backwards */
+void buf_incrpos(buffer* buf, unsigned int incr);
+void buf_decrpos(buffer* buf, unsigned int decr);
 void buf_incrwritepos(buffer* buf, unsigned int incr);
 unsigned char buf_getbyte(buffer* buf);
 unsigned char buf_getbool(buffer* buf);