static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['int bn_rsa_fips186_4_gen_prob_primes(BIGNUM *p, BIGNUM *Xpout,\n                                     BIGNUM *p1, BIGNUM *p2,\n                                     const BIGNUM *Xp, const BIGNUM *Xp1,\n                                     const BIGNUM *Xp2, int nlen,\n                                     const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)\n{\n    int ret = 0;\n    BIGNUM *p1i = NULL, *p2i = NULL, *Xp1i = NULL, *Xp2i = NULL;\n    int bitlen;\n    if (p == NULL || Xpout == NULL)\n        return 0;\n    BN_CTX_start(ctx);\n    p1i = (p1 != NULL) ? p1 : BN_CTX_get(ctx);\n    p2i = (p2 != NULL) ? p2 : BN_CTX_get(ctx);\n    Xp1i = (Xp1 != NULL) ? (BIGNUM *)Xp1 : BN_CTX_get(ctx);\n    Xp2i = (Xp2 != NULL) ? (BIGNUM *)Xp2 : BN_CTX_get(ctx);\n    if (p1i == NULL || p2i == NULL || Xp1i == NULL || Xp2i == NULL)\n        goto err;\n    bitlen = bn_rsa_fips186_4_aux_prime_min_size(nlen);\n    if (bitlen == 0)\n        goto err;\n    if (Xp1 == NULL) {\n        if (!BN_priv_rand(Xp1i, bitlen, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))\n            goto err;\n    }\n    if (Xp2 == NULL) {\n        if (!BN_priv_rand(Xp2i, bitlen, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))\n            goto err;\n    }\n    if (!bn_rsa_fips186_4_find_aux_prob_prime(Xp1i, p1i, ctx, cb)\n            || !bn_rsa_fips186_4_find_aux_prob_prime(Xp2i, p2i, ctx, cb))\n        goto err;\n    if ((BN_num_bits(p1i) + BN_num_bits(p2i)) >=\n            bn_rsa_fips186_4_aux_prime_max_sum_size_for_prob_primes(nlen))\n        goto err;\n    if (!bn_rsa_fips186_4_derive_prime(p, Xpout, Xp, p1i, p2i, nlen, e, ctx, cb))\n        goto err;\n    ret = 1;\nerr:\n    if (p1 == NULL)\n        BN_clear(p1i);\n    if (p2 == NULL)\n        BN_clear(p2i);\n    if (Xp1 == NULL)\n        BN_clear(Xp1i);\n    if (Xp2 == NULL)\n        BN_clear(Xp2i);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'static int bn_rsa_fips186_4_find_aux_prob_prime(const BIGNUM *Xp1,\n                                                BIGNUM *p1, BN_CTX *ctx,\n                                                BN_GENCB *cb)\n{\n    int ret = 0;\n    int i = 0;\n    int checks = bn_rsa_fips186_4_aux_prime_MR_min_checks(BN_num_bits(Xp1));\n    if (checks == 0 || BN_copy(p1, Xp1) == NULL)\n        return 0;\n    for(;;) {\n        i++;\n        BN_GENCB_call(cb, 0, i);\n        if (BN_is_prime_fasttest_ex(p1, checks, ctx, 1, cb))\n            break;\n        if (!BN_add_word(p1, 2))\n            goto err;\n    }\n    BN_GENCB_call(cb, 2, i);\n    ret = 1;\nerr:\n    return ret;\n}', 'int bn_rsa_fips186_4_derive_prime(BIGNUM *Y, BIGNUM *X, const BIGNUM *Xin,\n                                  const BIGNUM *r1, const BIGNUM *r2, int nlen,\n                                  const BIGNUM *e, BN_CTX *ctx, BN_GENCB *cb)\n{\n    int ret = 0;\n    int i, imax;\n    int bits = nlen >> 1;\n    int checks = bn_rsa_fips186_4_prime_MR_min_checks(nlen);\n    BIGNUM *tmp, *R, *r1r2x2, *y1, *r1x2;\n    if (checks == 0)\n        return 0;\n    BN_CTX_start(ctx);\n    R = BN_CTX_get(ctx);\n    tmp = BN_CTX_get(ctx);\n    r1r2x2 = BN_CTX_get(ctx);\n    y1 = BN_CTX_get(ctx);\n    r1x2 = BN_CTX_get(ctx);\n    if (r1x2 == NULL)\n        goto err;\n    if (Xin != NULL && BN_copy(X, Xin) == NULL)\n        goto err;\n    if (!(BN_lshift1(r1x2, r1)\n            && BN_gcd(tmp, r1x2, r2, ctx)\n            && BN_is_one(tmp)\n            && BN_mod_inverse(R, r2, r1x2, ctx)\n            && BN_mul(R, R, r2, ctx)\n            && BN_mod_inverse(tmp, r1x2, r2, ctx)\n            && BN_mul(tmp, tmp, r1x2, ctx)\n            && BN_sub(R, R, tmp)\n            && BN_mul(r1r2x2, r1x2, r2, ctx)))\n        goto err;\n    if (BN_is_negative(R) && !BN_add(R, R, r1r2x2))\n        goto err;\n    imax = 5 * bits;\n    for (;;) {\n        if (Xin == NULL) {\n            if (!BN_priv_rand(X, bits, BN_RAND_TOP_TWO, BN_RAND_BOTTOM_ANY))\n                goto end;\n        }\n        if (!BN_mod_sub(Y, R, X, r1r2x2, ctx) || !BN_add(Y, Y, X))\n            goto err;\n        i = 0;\n        for (;;) {\n            if (BN_num_bits(Y) > bits) {\n                if (Xin == NULL)\n                    break;\n                else\n                    goto err;\n            }\n            BN_GENCB_call(cb, 0, 2);\n            if (BN_copy(y1, Y) == NULL\n                    || !BN_sub_word(y1, 1)\n                    || !BN_gcd(tmp, y1, e, ctx))\n                goto err;\n            if (BN_is_one(tmp)\n                    && BN_is_prime_fasttest_ex(Y, checks, ctx, 1, cb))\n                goto end;\n            if (++i >= imax || !BN_add(Y, Y, r1r2x2))\n                goto err;\n        }\n    }\nend:\n    ret = 1;\n    BN_GENCB_call(cb, 3, 0);\nerr:\n    BN_clear(y1);\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_start()", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        ctx->err_stack++;\n    else if (!BN_STACK_push(&ctx->stack, ctx->used)) {\n        BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        ctx->err_stack++;\n    }\n    CTXDBG("LEAVE BN_CTX_start()", ctx);\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_gcd(BIGNUM *r, const BIGNUM *in_a, const BIGNUM *in_b, BN_CTX *ctx)\n{\n    BIGNUM *a, *b, *t;\n    int ret = 0;\n    bn_check_top(in_a);\n    bn_check_top(in_b);\n    BN_CTX_start(ctx);\n    a = BN_CTX_get(ctx);\n    b = BN_CTX_get(ctx);\n    if (b == NULL)\n        goto err;\n    if (BN_copy(a, in_a) == NULL)\n        goto err;\n    if (BN_copy(b, in_b) == NULL)\n        goto err;\n    a->neg = 0;\n    b->neg = 0;\n    if (BN_cmp(a, b) < 0) {\n        t = a;\n        a = b;\n        b = t;\n    }\n    t = euclid(a, b);\n    if (t == NULL)\n        goto err;\n    if (BN_copy(r, t) == NULL)\n        goto err;\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    bn_check_top(r);\n    return ret;\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_end()", ctx);\n    if (ctx->err_stack)\n        ctx->err_stack--;\n    else {\n        unsigned int fp = BN_STACK_pop(&ctx->stack);\n        if (fp < ctx->used)\n            BN_POOL_release(&ctx->pool, ctx->used - fp);\n        ctx->used = fp;\n        ctx->too_many = 0;\n    }\n    CTXDBG("LEAVE BN_CTX_end()", ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']