BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
{
    bn_check_top(b);
    if (a == b)
        return a;
    if (bn_wexpand(a, b->top) == NULL)
        return NULL;
    if (b->top > 0)
        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
    a->top = b->top;
    a->neg = b->neg;
    bn_check_top(a);
    return a;
}
["char *BN_bn2dec(const BIGNUM *a)\n{\n    int i = 0, num, ok = 0, n, tbytes;\n    char *buf = NULL;\n    char *p;\n    BIGNUM *t = NULL;\n    BN_ULONG *bn_data = NULL, *lp;\n    int bn_data_num;\n    i = BN_num_bits(a) * 3;\n    num = (i / 10 + i / 1000 + 1) + 1;\n    tbytes = num + 3;\n    bn_data_num = num / BN_DEC_NUM + 1;\n    bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));\n    buf = OPENSSL_malloc(tbytes);\n    if ((buf == NULL) || (bn_data == NULL)) {\n        BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);\n        goto err;\n    }\n    if ((t = BN_dup(a)) == NULL)\n        goto err;\n    p = buf;\n    lp = bn_data;\n    if (BN_is_zero(t)) {\n        *(p++) = '0';\n        *(p++) = '\\0';\n    } else {\n        if (BN_is_negative(t))\n            *p++ = '-';\n        while (!BN_is_zero(t)) {\n            if (lp - bn_data >= bn_data_num)\n                goto err;\n            *lp = BN_div_word(t, BN_DEC_CONV);\n            if (*lp == (BN_ULONG)-1)\n                goto err;\n            lp++;\n        }\n        lp--;\n        n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT1, *lp);\n        if (n < 0)\n            goto err;\n        p += n;\n        while (lp != bn_data) {\n            lp--;\n            n = BIO_snprintf(p, tbytes - (size_t)(p - buf), BN_DEC_FMT2, *lp);\n            if (n < 0)\n                goto err;\n            p += n;\n        }\n    }\n    ok = 1;\n err:\n    OPENSSL_free(bn_data);\n    BN_free(t);\n    if (ok)\n        return buf;\n    OPENSSL_free(buf);\n    return NULL;\n}", 'int BN_num_bits(const BIGNUM *a)\n{\n    int i = a->top - 1;\n    bn_check_top(a);\n    if (BN_is_zero(a))\n        return 0;\n    return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));\n}', 'int BN_is_zero(const BIGNUM *a)\n{\n    return a->top == 0;\n}', 'BIGNUM *BN_dup(const BIGNUM *a)\n{\n    BIGNUM *t;\n    if (a == NULL)\n        return NULL;\n    bn_check_top(a);\n    t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new();\n    if (t == NULL)\n        return NULL;\n    if (!BN_copy(t, a)) {\n        BN_free(t);\n        return NULL;\n    }\n    bn_check_top(t);\n    return t;\n}', 'BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)\n{\n    bn_check_top(b);\n    if (a == b)\n        return a;\n    if (bn_wexpand(a, b->top) == NULL)\n        return NULL;\n    if (b->top > 0)\n        memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);\n    a->top = b->top;\n    a->neg = b->neg;\n    bn_check_top(a);\n    return a;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}']