static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
{
    BN_ULONG *a = NULL;
    if (words > (INT_MAX / (4 * BN_BITS2))) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
        return NULL;
    }
    if (BN_get_flags(b, BN_FLG_SECURE))
        a = OPENSSL_secure_zalloc(words * sizeof(*a));
    else
        a = OPENSSL_zalloc(words * sizeof(*a));
    if (a == NULL) {
        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    assert(b->top <= words);
    if (b->top > 0)
        memcpy(a, b->d, sizeof(*a) * b->top);
    return a;
}
['int BN_GF2m_mod_exp_arr(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,\n                        const int p[], BN_CTX *ctx)\n{\n    int ret = 0, i, n;\n    BIGNUM *u;\n    bn_check_top(a);\n    bn_check_top(b);\n    if (BN_is_zero(b))\n        return BN_one(r);\n    if (BN_abs_is_word(b, 1))\n        return (BN_copy(r, a) != NULL);\n    BN_CTX_start(ctx);\n    if ((u = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (!BN_GF2m_mod_arr(u, a, p))\n        goto err;\n    n = BN_num_bits(b) - 1;\n    for (i = n - 1; i >= 0; i--) {\n        if (!BN_GF2m_mod_sqr_arr(u, u, p, ctx))\n            goto err;\n        if (BN_is_bit_set(b, i)) {\n            if (!BN_GF2m_mod_mul_arr(u, u, a, p, ctx))\n                goto err;\n        }\n    }\n    if (!BN_copy(r, u))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'BIGNUM *BN_CTX_get(BN_CTX *ctx)\n{\n    BIGNUM *ret;\n    CTXDBG("ENTER BN_CTX_get()", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        return NULL;\n    if ((ret = BN_POOL_get(&ctx->pool, ctx->flags)) == NULL) {\n        ctx->too_many = 1;\n        BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        return NULL;\n    }\n    BN_zero(ret);\n    ret->flags &= (~BN_FLG_CONSTTIME);\n    ctx->used++;\n    CTXDBG("LEAVE BN_CTX_get()", ctx);\n    return ret;\n}', 'int BN_set_word(BIGNUM *a, BN_ULONG w)\n{\n    bn_check_top(a);\n    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)\n        return 0;\n    a->neg = 0;\n    a->d[0] = w;\n    a->top = (w ? 1 : 0);\n    a->flags &= ~BN_FLG_FIXED_TOP;\n    bn_check_top(a);\n    return 1;\n}', 'int BN_GF2m_mod_arr(BIGNUM *r, const BIGNUM *a, const int p[])\n{\n    int j, k;\n    int n, dN, d0, d1;\n    BN_ULONG zz, *z;\n    bn_check_top(a);\n    if (!p[0]) {\n        BN_zero(r);\n        return 1;\n    }\n    if (a != r) {\n        if (!bn_wexpand(r, a->top))\n            return 0;\n        for (j = 0; j < a->top; j++) {\n            r->d[j] = a->d[j];\n        }\n        r->top = a->top;\n    }\n    z = r->d;\n    dN = p[0] / BN_BITS2;\n    for (j = r->top - 1; j > dN;) {\n        zz = z[j];\n        if (z[j] == 0) {\n            j--;\n            continue;\n        }\n        z[j] = 0;\n        for (k = 1; p[k] != 0; k++) {\n            n = p[0] - p[k];\n            d0 = n % BN_BITS2;\n            d1 = BN_BITS2 - d0;\n            n /= BN_BITS2;\n            z[j - n] ^= (zz >> d0);\n            if (d0)\n                z[j - n - 1] ^= (zz << d1);\n        }\n        n = dN;\n        d0 = p[0] % BN_BITS2;\n        d1 = BN_BITS2 - d0;\n        z[j - n] ^= (zz >> d0);\n        if (d0)\n            z[j - n - 1] ^= (zz << d1);\n    }\n    while (j == dN) {\n        d0 = p[0] % BN_BITS2;\n        zz = z[dN] >> d0;\n        if (zz == 0)\n            break;\n        d1 = BN_BITS2 - d0;\n        if (d0)\n            z[dN] = (z[dN] << d1) >> d1;\n        else\n            z[dN] = 0;\n        z[0] ^= zz;\n        for (k = 1; p[k] != 0; k++) {\n            BN_ULONG tmp_ulong;\n            n = p[k] / BN_BITS2;\n            d0 = p[k] % BN_BITS2;\n            d1 = BN_BITS2 - d0;\n            z[n] ^= (zz << d0);\n            if (d0 && (tmp_ulong = zz >> d1))\n                z[n + 1] ^= tmp_ulong;\n        }\n    }\n    bn_correct_top(r);\n    return 1;\n}', 'BIGNUM *bn_wexpand(BIGNUM *a, int words)\n{\n    return (words <= a->dmax) ? a : bn_expand2(a, words);\n}', 'BIGNUM *bn_expand2(BIGNUM *b, int words)\n{\n    if (words > b->dmax) {\n        BN_ULONG *a = bn_expand_internal(b, words);\n        if (!a)\n            return NULL;\n        if (b->d) {\n            OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));\n            bn_free_d(b);\n        }\n        b->d = a;\n        b->dmax = words;\n    }\n    return b;\n}', 'static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)\n{\n    BN_ULONG *a = NULL;\n    if (words > (INT_MAX / (4 * BN_BITS2))) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);\n        return NULL;\n    }\n    if (BN_get_flags(b, BN_FLG_SECURE))\n        a = OPENSSL_secure_zalloc(words * sizeof(*a));\n    else\n        a = OPENSSL_zalloc(words * sizeof(*a));\n    if (a == NULL) {\n        BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);\n        return NULL;\n    }\n    assert(b->top <= words);\n    if (b->top > 0)\n        memcpy(a, b->d, sizeof(*a) * b->top);\n    return a;\n}']