/*
 * siprandom.c: relatively fast pseudo-random data generator
 *
 * Copyright (c) 2016, Přemysl Eric Janouch <p@janouch.name>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted.
 *
 * 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_make (argc, argv, opts, NULL, "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;
}