X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fmem%2Fmem.c;h=13027a2a7b0fec1b18ae386f9704d84aed41c5f1;hb=7a353c03e5e8cdd55cbc0917f9ecff5cf9beefdb;hp=5b4b3508090dfb10dc7eea9236eb42ed54b92834;hpb=428d3b0217b32892c2fd309358619a4877113833;p=ccan

diff --git a/ccan/mem/mem.c b/ccan/mem/mem.c
index 5b4b3508..13027a2a 100644
--- 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
+}