/*
 * uuid_time.c --- Interpret the time field from a uuid.  This program
 * 	violates the UUID abstraction barrier by reaching into the guts
 *	of a UUID and interpreting it.
 * 
 * Copyright (C) 1998, 1999 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU 
 * Library General Public License.
 * %End-Header%
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/time.h>
#include <time.h>

#include "uuidP.h"

time_t uuid_time(const uuid_t uu, struct timeval *ret_tv)
{
	struct uuid		uuid;
	__u32			high;
	struct timeval		tv;
	unsigned long long	clock_reg;

	uuid_unpack(uu, &uuid);
	
	high = uuid.time_mid | ((uuid.time_hi_and_version & 0xFFF) << 16);
	clock_reg = uuid.time_low | ((unsigned long long) high << 32);

	clock_reg -= (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;
	tv.tv_sec = clock_reg / 10000000;
	tv.tv_usec = (clock_reg % 10000000) / 10;

	if (ret_tv)
		*ret_tv = tv;

	return tv.tv_sec;
}

int uuid_type(const uuid_t uu)
{
	struct uuid		uuid;

	uuid_unpack(uu, &uuid);	
	return ((uuid.time_hi_and_version >> 12) & 0xF);
}

int uuid_variant(const uuid_t uu)
{
	struct uuid		uuid;
	int			var;

	uuid_unpack(uu, &uuid);	
	var = uuid.clock_seq;

	if ((var & 0x8000) == 0)
		return UUID_VARIANT_NCS;
	if ((var & 0x4000) == 0)
		return UUID_VARIANT_DCE;
	if ((var & 0x2000) == 0)
		return UUID_VARIANT_MICROSOFT;
	return UUID_VARIANT_OTHER;
}

#ifdef DEBUG
static const char *variant_string(int variant)
{
	switch (variant) {
	case UUID_VARIANT_NCS:
		return "NCS";
	case UUID_VARIANT_DCE:
		return "DCE";
	case UUID_VARIANT_MICROSOFT:
		return "Microsoft";
	default:
		return "Other";
	}
}

	
int
main(int argc, char **argv)
{
	uuid_t		buf;
	time_t		time_reg;
	struct timeval	tv;
	int		type, variant;

	if (argc != 2) {
		fprintf(stderr, "Usage: %s uuid\n", argv[0]);
		exit(1);
	}
	if (uuid_parse(argv[1], buf)) {
		fprintf(stderr, "Invalid UUID: %s\n", argv[1]);
		exit(1);
	}
	variant = uuid_variant(buf);
	type = uuid_type(buf);
	time_reg = uuid_time(buf, &tv);

	printf("UUID variant is %d (%s)\n", variant, variant_string(variant));
	if (variant != UUID_VARIANT_DCE) {
		printf("Warning: This program only knows how to interpret "
		       "DCE UUIDs.\n\tThe rest of the output is likely "
		       "to be incorrect!!\n");
	}
	printf("UUID type is %d", type);
	switch (type) {
	case 1:
		printf(" (time based)\n");
		break;
	case 2:
		printf(" (DCE)\n");
		break;
	case 3:
		printf(" (name-based)\n");
		break;
	case 4:
		printf(" (random)\n");
		break;
	default:
		printf("\n");
	}
	if (type != 1) {
		printf("Warning: not a time-based UUID, so UUID time "
		       "decoding will likely not work!\n");
	}
	printf("UUID time is: (%ld, %ld): %s\n", tv.tv_sec, tv.tv_usec,
	       ctime(&time_reg));
	
	return 0;
}
#endif
