From 74d634e562323265e8d207200395c2c91cc19299 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Janouch?= <p.janouch@gmail.com>
Date: Sun, 14 Feb 2016 19:28:22 +0100
Subject: Add siprandom

Based on an idea I got from a talk.
---
 siprandom.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 siprandom.c

(limited to 'siprandom.c')

diff --git a/siprandom.c b/siprandom.c
new file mode 100644
index 0000000..20e8545
--- /dev/null
+++ b/siprandom.c
@@ -0,0 +1,90 @@
+/*
+ * siprandom.c: relatively fast pseudo-random data generator
+ *
+ * Copyright (c) 2016, Přemysl Janouch <p.janouch@gmail.com>
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "config.h"
+#undef PROGRAM_NAME
+#define PROGRAM_NAME "siprandom"
+#include "liberty/liberty.c"
+
+static void
+parse_program_arguments (int argc, char **argv)
+{
+	static const struct opt opts[] =
+	{
+		{ 'd', "debug", NULL, 0, "run in debug mode" },
+		{ 'h', "help", NULL, 0, "display this help and exit" },
+		{ 'V', "version", NULL, 0, "output version information and exit" },
+		{ 0, NULL, NULL, 0, NULL }
+	};
+
+	struct opt_handler oh;
+	opt_handler_init (&oh, argc, argv, opts, "CONFIG", "PRNG.");
+
+	int c;
+	while ((c = opt_handler_get (&oh)) != -1)
+	switch (c)
+	{
+	case 'd':
+		g_debug_mode = true;
+		break;
+	case 'h':
+		opt_handler_usage (&oh, stdout);
+		exit (EXIT_SUCCESS);
+	case 'V':
+		printf (PROGRAM_NAME " " PROGRAM_VERSION "\n");
+		exit (EXIT_SUCCESS);
+	default:
+		print_error ("wrong options");
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (argc)
+	{
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+
+	opt_handler_free (&oh);
+}
+
+int
+main (int argc, char *argv[])
+{
+	parse_program_arguments (argc, argv);
+
+	uint64_t counter, hash;
+	struct error *e = NULL;
+	if (!random_bytes (g_siphash_key, sizeof g_siphash_key, &e)
+	 || !random_bytes (&counter,      sizeof counter,       &e)
+	 || !random_bytes (&hash,         sizeof hash,          &e))
+		exit_fatal ("%s: %s", "failed to obtain random data seed", e->message);
+
+	do
+	{
+		hash ^= siphash_wrapper (&counter, sizeof counter);
+		counter++;
+	}
+	while (fwrite (&hash, sizeof hash, 1, stdout) == 1);
+	return EXIT_SUCCESS;
+}
-- 
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