/*-
 * Copyright (c) 2017-2021 Ribose Inc.
 * Copyright (c) 2012 Alistair Crooks <agc@NetBSD.org>
 * All rights reserved.
 *
 * 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 above 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

#ifndef RNP_BN_H_
#define RNP_BN_H_

#include <stdio.h>
#include <stdint.h>
#include "config.h"
#include "mpi.h"

#if defined(CRYPTO_BACKEND_OPENSSL)
#include <openssl/bn.h>

#define bignum_t BIGNUM
#elif defined(CRYPTO_BACKEND_BOTAN)
typedef struct botan_mp_struct *botan_mp_t;
typedef struct bignum_t_st {
    botan_mp_t mp;
} bignum_t;

#define BN_HANDLE(x) ((x).mp)
#define BN_HANDLE_PTR(x) ((x)->mp)
#else
#error "Unknown crypto backend."
#endif

/*********************************/

bignum_t *bn_new(void);
void      bn_free(bignum_t * /*a*/);

int bn_bn2bin(const bignum_t * /*a*/, unsigned char * /*b*/);

bignum_t *mpi2bn(const pgp_mpi_t *val);

bool bn2mpi(const bignum_t *bn, pgp_mpi_t *val);

size_t bn_num_bytes(const bignum_t &a);

#if defined(CRYPTO_BACKEND_OPENSSL)
namespace rnp {
class bn {
    BIGNUM *_bn;

  public:
    bn(BIGNUM *val = NULL) : _bn(val)
    {
    }

    bn(const pgp_mpi_t &val) : _bn(mpi2bn(&val))
    {
    }

    ~bn()
    {
        BN_free(_bn);
    }

    void
    set(BIGNUM *val = NULL) noexcept
    {
        BN_free(_bn);
        _bn = val;
    }

    void
    set(const pgp_mpi_t &val) noexcept
    {
        BN_free(_bn);
        _bn = mpi2bn(&val);
    }

    BIGNUM **
    ptr() noexcept
    {
        set();
        return &_bn;
    }

    BIGNUM *
    get() noexcept
    {
        return _bn;
    }

    BIGNUM *
    own() noexcept
    {
        auto res = _bn;
        _bn = NULL;
        return res;
    }

    size_t
    bytes() const noexcept
    {
        return BN_num_bytes(_bn);
    }

    bool
    bin(uint8_t *b) const noexcept
    {
        if (!b) {
            return false;
        }
        return BN_bn2bin(_bn, b) >= 0;
    }

    bool
    mpi(pgp_mpi_t &mpi) const noexcept
    {
        return bn2mpi(_bn, &mpi);
    }
};
}; // namespace rnp
#endif

#endif