use of int and overflow review

[chiark-tcl.git] / hbytes / hbytes.c

diff --git a/hbytes/hbytes.c b/hbytes/hbytes.c
index 22383df0d05f889201d380e1e6c7ab79daffbc8d..15980dcd6024e7518c8f60a7c1ba72bfb295f3d3 100644 (file)
--- a/hbytes/hbytes.c
+++ b/hbytes/hbytes.c
@@ -1,7 +1,24 @@
 /*
+ * hbytes - hex-stringrep efficient byteblocks for Tcl
+ * Copyright 2006 Ian Jackson
  *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
  */
 
+
 #include "hbytes.h"
 
 #define COMPLEX(hb) ((HBytes_ComplexValue*)hb->begin_complex)
@@ -81,6 +98,8 @@ Byte *cht_hb_prepend(HBytes_Value *hb, int el) {
   Byte *old_block, *new_block, *new_dstart;
 
   cx= complex(hb);
+
+  assert(el < INT_MAX/4 && cx->len < INT_MAX/2);
   
   if (cx->prespace < el) {
     new_prespace= el*2 + cx->len;
@@ -104,6 +123,7 @@ Byte *cht_hb_append(HBytes_Value *hb, int el) {
   Byte *newpart, *new_block, *old_block;
 
   cx= complex(hb);
+  assert(el < INT_MAX/4 && cx->len < INT_MAX/4);
 
   new_len= cx->len + el;
   if (new_len > cx->avail) {