mbuf: mbuf_cut() function

diff --git a/usual/mbuf.h b/usual/mbuf.h
index fac69d71a982ac7c4efc6fddf29fddf08d715070..aa0ae81ac2ab41b28cba72ca966ebed7a9a83e61 100644 (file)
--- a/usual/mbuf.h
+++ b/usual/mbuf.h
@@ -230,5 +230,21 @@ static inline bool mbuf_fill(struct MBuf *buf, uint8_t byte, unsigned len)
        return true;
 }
 
+/* remove some data from buf */
+_MUSTCHECK
+static inline bool mbuf_cut(struct MBuf *buf, unsigned ofs, unsigned len)
+{
+       if (buf->reader)
+               return false;
+       if (ofs + len < buf->write_pos) {
+               unsigned endofs = ofs + len;
+               memmove(buf->data + ofs, buf->data + endofs, buf->write_pos - endofs);
+               buf->write_pos -= len;
+       } else if (ofs < buf->write_pos) {
+               buf->write_pos = ofs;
+       }
+       return true;
+}
+
 #endif