1 files changed, 42 insertions, 0 deletions
diff --git a/src/zand.c b/src/zand.c
new file mode 100644
index 0000000..3156857
--- /dev/null
+++ b/src/zand.c
@@ -0,0 +1,42 @@
+/* See LICENSE file for copyright and license details. */
+#include "internals"
+
+#include <string.h>
+
+
+void
+zand(z_t a, z_t b, z_t c)
+{
+	size_t n;
+
+	if (zzero(b) || zzero(c)) {
+		SET_SIGNUM(a, 0);
+		return;
+	}
+
+	n = b->used < c->used ? b->used : c->used;
+	while (n--)
+		if (b->chars[n] & c->chars[n])
+			goto found_highest;
+	SET_SIGNUM(a, 0);
+	return;
+
+found_highest:
+	a->used = ++n;
+	if (a == b) {
+		while (n--)
+			a->chars[n] &= c->chars[n];
+	} else if (a == c) {
+		while (n--)
+			a->chars[n] &= b->chars[n];
+	} else {
+		if (a->alloced < a->used) {
+			a->alloced = a->used;
+			a->chars = realloc(a->chars, a->used * sizeof(*(a->chars)));
+		}
+		memcpy(a->chars, c->chars, a->used * sizeof(*(a->chars)));
+		while (n--)
+			a->chars[n] &= b->chars[n];
+	}
+	SET_SIGNUM(a, (zsignum(b) > 0 || zsignum(c) > 0) * 2 - 1);
+}