--- a/buffer.h	Sat Jun 24 23:33:16 2017 +0800
+++ b/buffer.h	Fri Feb 09 23:49:22 2018 +0800
@@ -44,8 +44,8 @@
 /* Possibly returns a new buffer*, like realloc() */
 buffer * buf_resize(buffer *buf, unsigned int newsize);
 void buf_free(buffer* buf);
-void buf_burn(buffer* buf);
-buffer* buf_newcopy(buffer* buf);
+void buf_burn(const buffer* buf);
+buffer* buf_newcopy(const buffer* buf);
 void buf_setlen(buffer* buf, unsigned int len);
 void buf_incrlen(buffer* buf, unsigned int incr);
 void buf_setpos(buffer* buf, unsigned int pos);
@@ -54,8 +54,8 @@
 unsigned char buf_getbyte(buffer* buf);
 unsigned char buf_getbool(buffer* buf);
 void buf_putbyte(buffer* buf, unsigned char val);
-unsigned char* buf_getptr(buffer* buf, unsigned int len);
-unsigned char* buf_getwriteptr(buffer* buf, unsigned int len);
+unsigned char* buf_getptr(const buffer* buf, unsigned int len);
+unsigned char* buf_getwriteptr(const buffer* buf, unsigned int len);
 char* buf_getstring(buffer* buf, unsigned int *retlen);
 buffer * buf_getstringbuf(buffer *buf);
 void buf_eatstring(buffer *buf);