1 files changed, 63 insertions, 0 deletions
diff --git a/libnormalform_xor2.c b/libnormalform_xor2.c
new file mode 100644
index 0000000..a00c575
--- /dev/null
+++ b/libnormalform_xor2.c
@@ -0,0 +1,63 @@
+/* See LICENSE file for copyright and license details. */
+#ifndef TEST
+#include "common.h"
+
+
+LIBNORMALFORM_SENTENCE *
+(libnormalform_xor2)(LIBNORMALFORM_SENTENCE *l, LIBNORMALFORM_SENTENCE *r)
+{
+	int inv;
+
+	if (!l || !r) {
+		libnormalform_free(l);
+		libnormalform_free(r);
+		return NULL;
+	}
+
+        if (l->equals(l, r, &inv)) {
+		libnormalform_free(l);
+		libnormalform_free(r);
+
+		if (!inv) {
+			/* x ⊕ x = 0 */
+			return libnormalform_false();
+
+		} else {
+			/* x ⊕ ¬x = 1 */
+			return libnormalform_true();
+		}
+
+	} else if (l->type == TYPE_TRUE) {
+		/* 1 ⊕ x = (1 ∨ x) ∧ ¬(1 ∧ x) = 1 ∧ ¬x = ¬x */
+		r = libnormalform_not(r);
+	return_r:
+		libnormalform_free(l);
+		return r;
+
+	} else if (l->type == TYPE_FALSE) {
+		/* 0 ⊕ x = (0 ∨ x) ∧ ¬(0 ∧ x) = x ∧ ¬0 = x ∧ 1 = x */
+		goto return_r;
+
+	} else if (r->type == TYPE_TRUE) {
+		/* x ⊕ 1 = 1 ⊕ x = ¬x */
+		l = libnormalform_not(l);
+	return_l:
+		libnormalform_free(r);
+		return l;
+
+	} else if (r->type == TYPE_FALSE) {
+		/* x ⊕ 0 = 0 ⊕ x = x */
+		goto return_l;
+
+	} else {
+		return libnormalform_xor2__(l, r);
+	}
+}
+
+
+#else
+
+#define USE_TWO
+#include "libnormalform_xor.c"
+
+#endif