tcon: add testcase for const members in tcon_container_of()

[ccan] / ccan / mem / mem.c

diff --git a/ccan/mem/mem.c b/ccan/mem/mem.c
index 5b4b3508090dfb10dc7eea9236eb42ed54b92834..13027a2a7b0fec1b18ae386f9704d84aed41c5f1 100644 (file)
--- a/ccan/mem/mem.c
+++ b/ccan/mem/mem.c
@@ -88,3 +88,41 @@ void memswap(void *a, void *b, size_t n)
                n -= m;
        }
 }
+
+bool memeqzero(const void *data, size_t length)
+{
+       const unsigned char *p = data;
+       size_t len;
+
+       /* Check first 16 bytes manually */
+       for (len = 0; len < 16; len++) {
+               if (!length)
+                       return true;
+               if (*p)
+                       return false;
+               p++;
+               length--;
+       }
+
+       /* Now we know that's zero, memcmp with self. */
+       return memcmp(data, p, length) == 0;
+}
+
+void memtaint(void *data, size_t len)
+{
+       /* Using 16 bytes is a bit quicker than 4 */
+       const unsigned tainter[]
+               = { 0xdeadbeef, 0xdeadbeef, 0xdeadbeef, 0xdeadbeef };
+       char *p = data;
+
+       while (len >= sizeof(tainter)) {
+               memcpy(p, tainter, sizeof(tainter));
+               p += sizeof(tainter);
+               len -= sizeof(tainter);
+       }
+       memcpy(p, tainter, len);
+
+#if HAVE_VALGRIND_MEMCHECK_H
+       VALGRIND_MAKE_MEM_UNDEFINED(data, len);
+#endif
+}