X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/blobdiff_plain/b2e3cab6544444137fe7aadee2a991adbfde97c4..1c3b0c0e6f9339e76e42f6393e554c7dfc58e205:/t/rng-test.c

diff --git a/t/rng-test.c b/t/rng-test.c
new file mode 100644
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--- /dev/null
+++ b/t/rng-test.c
@@ -0,0 +1,80 @@
+/*
+ * Simple random number generator for testing.
+ * Copyright © 2022 Nick Bowler
+ *
+ * Directly compare the test lib RNG against the reference implementation.
+ *
+ * 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 3 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 program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdlib.h>
+
+#include "rng.c"
+#include "xos256p.c"
+
+int main(void)
+{
+	unsigned long long seed_state = 0xdeadbeeff00dcafe;
+	unsigned long long test_result, ref_result;
+	unsigned long long ref_state[4], test_state[4];
+	int i, ret = 0;
+
+	printf("1..200\n");
+	for (i = 0; i < 100; i++) {
+		s[0] = ref_state[0] = test_state[0] = splitmix64(&seed_state);
+		s[1] = ref_state[1] = test_state[1] = splitmix64(&seed_state);
+		s[2] = ref_state[2] = test_state[2] = splitmix64(&seed_state);
+		s[3] = ref_state[3] = test_state[3] = splitmix64(&seed_state);
+
+		ref_result = next();
+		test_result = xoshiro256p(test_state);
+
+		if (ref_result != test_result) {
+			printf("not ok %d rng output\n", 2*i+1);
+			printf("# Failed, unexpected result\n");
+			printf("#   with initial state %llx %llx %llx %llx\n",
+			       ref_state[0], ref_state[1],
+			       ref_state[2], ref_state[3]);
+			printf("#   received: %llx\n", test_result);
+			printf("#   expected: %llx\n", ref_result);
+			ret = EXIT_FAILURE;
+		} else {
+			printf("ok %d rng output\n", 2*i+1);
+		}
+
+		if (s[0] != test_state[0] || s[1] != test_state[1]
+		    || s[2] != test_state[2] || s[3] != test_state[3])
+		{
+			printf("not ok %d rng state update\n", 2*i+2);
+			printf("# Failed, state update differed\n");
+			printf("#   with initial state %llx %llx %llx %llx\n",
+			       ref_state[0], ref_state[1],
+			       ref_state[2], ref_state[3]);
+			printf("#   received: %llx %llx %llx %llx\n",
+			       test_state[0], test_state[1],
+			       test_state[2], test_state[3]);
+			printf("#   expected: %llx %llx %llx %llx\n",
+			       (unsigned long long)s[0],
+			       (unsigned long long)s[1],
+			       (unsigned long long)s[2],
+			       (unsigned long long)s[3]);
+			ret = EXIT_FAILURE;
+		} else {
+			printf("ok %d rng state update\n", 2*i+2);
+		}
+	}
+
+	return ret;
+}