/*

 * Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <openssl/crypto.h>

#include <openssl/err.h>

#include "ec_local.h"

BIGNUM *EC_POINT_point2bn(const EC_GROUP *group,

                          const EC_POINT *point,

                          point_conversion_form_t form,

                          BIGNUM *ret, BN_CTX *ctx)

{

    size_t buf_len = 0;

    unsigned char *buf;

    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);

    if (buf_len == 0)

        return NULL;

    ret = BN_bin2bn(buf, buf_len, ret);

    OPENSSL_free(buf);

    return ret;

}

EC_POINT *EC_POINT_bn2point(const EC_GROUP *group,

                            const BIGNUM *bn, EC_POINT *point, BN_CTX *ctx)

{

    size_t buf_len = 0;

    unsigned char *buf;

    EC_POINT *ret;

    if ((buf_len = BN_num_bytes(bn)) == 0)

        buf_len = 1;

    if ((buf = OPENSSL_malloc(buf_len)) == NULL) {

        ECerr(EC_F_EC_POINT_BN2POINT, ERR_R_MALLOC_FAILURE);

        return NULL;

    }

    if (!BN_bn2binpad(bn, buf, buf_len)) {

        OPENSSL_free(buf);

        return NULL;

    }

    if (point == NULL) {

        if ((ret = EC_POINT_new(group)) == NULL) {

            OPENSSL_free(buf);

            return NULL;

        }

    } else

        ret = point;

    if (!EC_POINT_oct2point(group, ret, buf, buf_len, ctx)) {

        if (ret != point)

            EC_POINT_clear_free(ret);

        OPENSSL_free(buf);

        return NULL;

    }

    OPENSSL_free(buf);

    return ret;

}

static const char *HEX_DIGITS = "0123456789ABCDEF";

/* the return value must be freed (using OPENSSL_free()) */

char *EC_POINT_point2hex(const EC_GROUP *group,

                         const EC_POINT *point,

                         point_conversion_form_t form, BN_CTX *ctx)

{

    char *ret, *p;

    size_t buf_len = 0, i;

    unsigned char *buf = NULL, *pbuf;

    buf_len = EC_POINT_point2buf(group, point, form, &buf, ctx);

    if (buf_len == 0)

        return NULL;

    ret = OPENSSL_malloc(buf_len * 2 + 2);

    if (ret == NULL) {

        OPENSSL_free(buf);

        return NULL;

    }

    p = ret;

    pbuf = buf;

    for (i = buf_len; i > 0; i--) {

        int v = (int)*(pbuf++);

        *(p++) = HEX_DIGITS[v >> 4];

        *(p++) = HEX_DIGITS[v & 0x0F];

    }

    *p = '\0';

    OPENSSL_free(buf);

    return ret;

}

EC_POINT *EC_POINT_hex2point(const EC_GROUP *group,

                             const char *buf, EC_POINT *point, BN_CTX *ctx)

{

    EC_POINT *ret = NULL;

    BIGNUM *tmp_bn = NULL;

    if (!BN_hex2bn(&tmp_bn, buf))

        return NULL;

    ret = EC_POINT_bn2point(group, tmp_bn, point, ctx);

    BN_clear_free(tmp_bn);

    return ret;

}