/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

/* $Id: ttl.c,v 1.6 2020/09/14 08:40:43 florian Exp $ */

/*! \file */

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include <isc/buffer.h>
#include <isc/region.h>
#include <isc/util.h>

#include <dns/ttl.h>

#define RETERR(x) do { \
        isc_result_t _r = (x); \
        if (_r != ISC_R_SUCCESS) \
                return (_r); \
        } while (0)

/*
 * Helper for dns_ttl_totext().
 */
static isc_result_t
ttlfmt(unsigned int t, const char *s, int verbose,
       int space, isc_buffer_t *target)
{
        char tmp[60];
        unsigned int len;
        isc_region_t region;

        if (verbose)
                len = snprintf(tmp, sizeof(tmp), "%s%u %s%s",
                               space ? " " : "",
                               t, s,
                               t == 1 ? "" : "s");
        else
                len = snprintf(tmp, sizeof(tmp), "%u%c", t, s[0]);

        INSIST(len + 1 <= sizeof(tmp));
        isc_buffer_availableregion(target, &region);
        if (len > region.length)
                return (ISC_R_NOSPACE);
        memmove(region.base, tmp, len);
        isc_buffer_add(target, len);

        return (ISC_R_SUCCESS);
}

/*
 * Derived from bind8 ns_format_ttl().
 */
isc_result_t
dns_ttl_totext(uint32_t src, int verbose, isc_buffer_t *target) {
        unsigned secs, mins, hours, days, weeks, x;

        secs = src % 60;   src /= 60;
        mins = src % 60;   src /= 60;
        hours = src % 24;  src /= 24;
        days = src % 7;    src /= 7;
        weeks = src;       src = 0;
        POST(src);

        x = 0;
        if (weeks != 0) {
                RETERR(ttlfmt(weeks, "week", verbose, (x > 0), target));
                x++;
        }
        if (days != 0) {
                RETERR(ttlfmt(days, "day", verbose, (x > 0), target));
                x++;
        }
        if (hours != 0) {
                RETERR(ttlfmt(hours, "hour", verbose, (x > 0), target));
                x++;
        }
        if (mins != 0) {
                RETERR(ttlfmt(mins, "minute", verbose, (x > 0), target));
                x++;
        }
        if (secs != 0 ||
            (weeks == 0 && days == 0 && hours == 0 && mins == 0)) {
                RETERR(ttlfmt(secs, "second", verbose, (x > 0), target));
                x++;
        }
        INSIST (x > 0);
        /*
         * If only a single unit letter is printed, print it
         * in upper case. (Why?  Because BIND 8 does that.
         * Presumably it has a reason.)
         */
        if (x == 1 && !verbose) {
                isc_region_t region;
                /*
                 * The unit letter is the last character in the
                 * used region of the buffer.
                 *
                 * toupper() does not need its argument to be masked of cast
                 * here because region.base is type unsigned char *.
                 */
                isc_buffer_usedregion(target, &region);
                region.base[region.length - 1] =
                        toupper(region.base[region.length - 1]);
        }
        return (ISC_R_SUCCESS);
}