/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#include <openssl/asn1.h>

#include <string.h>
#include <time.h>

#include <openssl/asn1t.h>
#include <openssl/buf.h>
#include <openssl/err.h>
#include <openssl/mem.h>

#include "asn1_locl.h"

/*
 * This is an implementation of the ASN1 Time structure which is: Time ::=
 * CHOICE { utcTime UTCTime, generalTime GeneralizedTime } written by Steve
 * Henson.
 */

IMPLEMENT_ASN1_MSTRING(ASN1_TIME, B_ASN1_TIME)

IMPLEMENT_ASN1_FUNCTIONS(ASN1_TIME)

ASN1_TIME *ASN1_TIME_set(ASN1_TIME *s, time_t t)
{
    return ASN1_TIME_adj(s, t, 0, 0);
}

ASN1_TIME *ASN1_TIME_adj(ASN1_TIME *s, time_t t,
                         int offset_day, long offset_sec)
{
    struct tm *ts;
    struct tm data;

    ts = OPENSSL_gmtime(&t, &data);
    if (ts == NULL) {
        OPENSSL_PUT_ERROR(ASN1, ASN1_R_ERROR_GETTING_TIME);
        return NULL;
    }
    if (offset_day || offset_sec) {
        if (!OPENSSL_gmtime_adj(ts, offset_day, offset_sec))
            return NULL;
    }
    if ((ts->tm_year >= 50) && (ts->tm_year < 150))
        return ASN1_UTCTIME_adj(s, t, offset_day, offset_sec);
    return ASN1_GENERALIZEDTIME_adj(s, t, offset_day, offset_sec);
}

int ASN1_TIME_check(ASN1_TIME *t)
{
    if (t->type == V_ASN1_GENERALIZEDTIME)
        return ASN1_GENERALIZEDTIME_check(t);
    else if (t->type == V_ASN1_UTCTIME)
        return ASN1_UTCTIME_check(t);
    return 0;
}

/* Convert an ASN1_TIME structure to GeneralizedTime */
ASN1_GENERALIZEDTIME *ASN1_TIME_to_generalizedtime(ASN1_TIME *t,
                                                   ASN1_GENERALIZEDTIME **out)
{
    ASN1_GENERALIZEDTIME *ret = NULL;
    char *str;
    int newlen;

    if (!ASN1_TIME_check(t))
        return NULL;

    if (!out || !*out) {
        if (!(ret = ASN1_GENERALIZEDTIME_new()))
            goto err;
    } else {
        ret = *out;
    }

    /* If already GeneralizedTime just copy across */
    if (t->type == V_ASN1_GENERALIZEDTIME) {
        if (!ASN1_STRING_set(ret, t->data, t->length))
            goto err;
        goto done;
    }

    /* grow the string */
    if (!ASN1_STRING_set(ret, NULL, t->length + 2))
        goto err;
    /* ASN1_STRING_set() allocated 'len + 1' bytes. */
    newlen = t->length + 2 + 1;
    str = (char *)ret->data;
    /* Work out the century and prepend */
    if (t->data[0] >= '5')
        BUF_strlcpy(str, "19", newlen);
    else
        BUF_strlcpy(str, "20", newlen);

    BUF_strlcat(str, (char *)t->data, newlen);

 done:
   if (out != NULL && *out == NULL)
       *out = ret;
   return ret;

 err:
    if (out == NULL || *out != ret)
        ASN1_GENERALIZEDTIME_free(ret);
    return NULL;
}


int ASN1_TIME_set_string(ASN1_TIME *s, const char *str)
{
    ASN1_TIME t;

    t.length = strlen(str);
    t.data = (unsigned char *)str;
    t.flags = 0;

    t.type = V_ASN1_UTCTIME;

    if (!ASN1_TIME_check(&t)) {
        t.type = V_ASN1_GENERALIZEDTIME;
        if (!ASN1_TIME_check(&t))
            return 0;
    }

    if (s && !ASN1_STRING_copy((ASN1_STRING *)s, (ASN1_STRING *)&t))
        return 0;

    return 1;
}

static int asn1_time_to_tm(struct tm *tm, const ASN1_TIME *t)
{
    if (t == NULL) {
        time_t now_t;
        time(&now_t);
        if (OPENSSL_gmtime(&now_t, tm))
            return 1;
        return 0;
    }

    if (t->type == V_ASN1_UTCTIME)
        return asn1_utctime_to_tm(tm, t);
    else if (t->type == V_ASN1_GENERALIZEDTIME)
        return asn1_generalizedtime_to_tm(tm, t);

    return 0;
}

int ASN1_TIME_diff(int *pday, int *psec,
                   const ASN1_TIME *from, const ASN1_TIME *to)
{
    struct tm tm_from, tm_to;
    if (!asn1_time_to_tm(&tm_from, from))
        return 0;
    if (!asn1_time_to_tm(&tm_to, to))
        return 0;
    return OPENSSL_gmtime_diff(pday, psec, &tm_from, &tm_to);
}
