static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)\n{\n    BIGNUM *kinv = NULL;\n    BIGNUM *m;\n    BIGNUM *xr;\n    BN_CTX *ctx = NULL;\n    int reason = ERR_R_BN_LIB;\n    DSA_SIG *ret = NULL;\n    int rv = 0;\n    m = BN_new();\n    xr = BN_new();\n    if (m == NULL || xr == NULL)\n        goto err;\n    if (!dsa->p || !dsa->q || !dsa->g) {\n        reason = DSA_R_MISSING_PARAMETERS;\n        goto err;\n    }\n    ret = DSA_SIG_new();\n    if (ret == NULL)\n        goto err;\n    ret->r = BN_new();\n    ret->s = BN_new();\n    if (ret->r == NULL || ret->s == NULL)\n        goto err;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n redo:\n    if (!dsa_sign_setup(dsa, ctx, &kinv, &ret->r, dgst, dlen))\n        goto err;\n    if (dlen > BN_num_bytes(dsa->q))\n        dlen = BN_num_bytes(dsa->q);\n    if (BN_bin2bn(dgst, dlen, m) == NULL)\n        goto err;\n    if (!BN_mod_mul(xr, dsa->priv_key, ret->r, dsa->q, ctx))\n        goto err;\n    if (!BN_add(ret->s, xr, m))\n        goto err;\n    if (BN_cmp(ret->s, dsa->q) > 0)\n        if (!BN_sub(ret->s, ret->s, dsa->q))\n            goto err;\n    if (!BN_mod_mul(ret->s, ret->s, kinv, dsa->q, ctx))\n        goto err;\n    if (BN_is_zero(ret->r) || BN_is_zero(ret->s))\n        goto redo;\n    rv = 1;\n err:\n    if (rv == 0) {\n        DSAerr(DSA_F_DSA_DO_SIGN, reason);\n        DSA_SIG_free(ret);\n        ret = NULL;\n    }\n    BN_CTX_free(ctx);\n    BN_clear_free(m);\n    BN_clear_free(xr);\n    BN_clear_free(kinv);\n    return ret;\n}', 'static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,\n                          BIGNUM **kinvp, BIGNUM **rp,\n                          const unsigned char *dgst, int dlen)\n{\n    BN_CTX *ctx = NULL;\n    BIGNUM *k, *kinv = NULL, *r = *rp;\n    int ret = 0;\n    if (!dsa->p || !dsa->q || !dsa->g) {\n        DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS);\n        return 0;\n    }\n    k = BN_new();\n    if (k == NULL)\n        goto err;\n    if (ctx_in == NULL) {\n        if ((ctx = BN_CTX_new()) == NULL)\n            goto err;\n    } else\n        ctx = ctx_in;\n    do {\n        if (dgst != NULL) {\n            if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,\n                                       dlen, ctx))\n                goto err;\n        } else if (!BN_rand_range(k, dsa->q))\n            goto err;\n    } while (BN_is_zero(k));\n    BN_set_flags(k, BN_FLG_CONSTTIME);\n    if (dsa->flags & DSA_FLAG_CACHE_MONT_P) {\n        if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,\n                                    dsa->lock, dsa->p, ctx))\n            goto err;\n    }\n    if (!BN_add(k, k, dsa->q))\n        goto err;\n    if (BN_num_bits(k) <= BN_num_bits(dsa->q)) {\n        if (!BN_add(k, k, dsa->q))\n            goto err;\n    }\n    if ((dsa)->meth->bn_mod_exp != NULL) {\n            if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, k, dsa->p, ctx,\n                                       dsa->method_mont_p))\n                goto err;\n    } else {\n            if (!BN_mod_exp_mont(r, dsa->g, k, dsa->p, ctx, dsa->method_mont_p))\n                goto err;\n    }\n    if (!BN_mod(r, r, dsa->q, ctx))\n        goto err;\n    if ((kinv = BN_mod_inverse(NULL, k, dsa->q, ctx)) == NULL)\n        goto err;\n    BN_clear_free(*kinvp);\n    *kinvp = kinv;\n    kinv = NULL;\n    ret = 1;\n err:\n    if (!ret)\n        DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB);\n    if (ctx != ctx_in)\n        BN_CTX_free(ctx);\n    BN_clear_free(k);\n    return ret;\n}', 'int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    BIGNUM *t;\n    int ret = 0;\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(m);\n    BN_CTX_start(ctx);\n    if ((t = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (a == b) {\n        if (!BN_sqr(t, a, ctx))\n            goto err;\n    } else {\n        if (!BN_mul(t, a, b, ctx))\n            goto err;\n    }\n    if (!BN_nnmod(r, t, m, ctx))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return (ret);\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("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_EXIT(ctx);\n}', 'int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)\n{\n    int ret = 0;\n    int top, al, bl;\n    BIGNUM *rr;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    int i;\n#endif\n#ifdef BN_RECURSION\n    BIGNUM *t = NULL;\n    int j = 0, k;\n#endif\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(r);\n    al = a->top;\n    bl = b->top;\n    if ((al == 0) || (bl == 0)) {\n        BN_zero(r);\n        return (1);\n    }\n    top = al + bl;\n    BN_CTX_start(ctx);\n    if ((r == a) || (r == b)) {\n        if ((rr = BN_CTX_get(ctx)) == NULL)\n            goto err;\n    } else\n        rr = r;\n    rr->neg = a->neg ^ b->neg;\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n    i = al - bl;\n#endif\n#ifdef BN_MUL_COMBA\n    if (i == 0) {\n# if 0\n        if (al == 4) {\n            if (bn_wexpand(rr, 8) == NULL)\n                goto err;\n            rr->top = 8;\n            bn_mul_comba4(rr->d, a->d, b->d);\n            goto end;\n        }\n# endif\n        if (al == 8) {\n            if (bn_wexpand(rr, 16) == NULL)\n                goto err;\n            rr->top = 16;\n            bn_mul_comba8(rr->d, a->d, b->d);\n            goto end;\n        }\n    }\n#endif\n#ifdef BN_RECURSION\n    if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL)) {\n        if (i >= -1 && i <= 1) {\n            if (i >= 0) {\n                j = BN_num_bits_word((BN_ULONG)al);\n            }\n            if (i == -1) {\n                j = BN_num_bits_word((BN_ULONG)bl);\n            }\n            j = 1 << (j - 1);\n            assert(j <= al || j <= bl);\n            k = j + j;\n            t = BN_CTX_get(ctx);\n            if (t == NULL)\n                goto err;\n            if (al > j || bl > j) {\n                if (bn_wexpand(t, k * 4) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 4) == NULL)\n                    goto err;\n                bn_mul_part_recursive(rr->d, a->d, b->d,\n                                      j, al - j, bl - j, t->d);\n            } else {\n                if (bn_wexpand(t, k * 2) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 2) == NULL)\n                    goto err;\n                bn_mul_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d);\n            }\n            rr->top = top;\n            goto end;\n        }\n# if 0\n        if (i == 1 && !BN_get_flags(b, BN_FLG_STATIC_DATA)) {\n            BIGNUM *tmp_bn = (BIGNUM *)b;\n            if (bn_wexpand(tmp_bn, al) == NULL)\n                goto err;\n            tmp_bn->d[bl] = 0;\n            bl++;\n            i--;\n        } else if (i == -1 && !BN_get_flags(a, BN_FLG_STATIC_DATA)) {\n            BIGNUM *tmp_bn = (BIGNUM *)a;\n            if (bn_wexpand(tmp_bn, bl) == NULL)\n                goto err;\n            tmp_bn->d[al] = 0;\n            al++;\n            i++;\n        }\n        if (i == 0) {\n            j = BN_num_bits_word((BN_ULONG)al);\n            j = 1 << (j - 1);\n            k = j + j;\n            t = BN_CTX_get(ctx);\n            if (al == j) {\n                if (bn_wexpand(t, k * 2) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 2) == NULL)\n                    goto err;\n                bn_mul_recursive(rr->d, a->d, b->d, al, t->d);\n            } else {\n                if (bn_wexpand(t, k * 4) == NULL)\n                    goto err;\n                if (bn_wexpand(rr, k * 4) == NULL)\n                    goto err;\n                bn_mul_part_recursive(rr->d, a->d, b->d, al - j, j, t->d);\n            }\n            rr->top = top;\n            goto end;\n        }\n# endif\n    }\n#endif\n    if (bn_wexpand(rr, top) == NULL)\n        goto err;\n    rr->top = top;\n    bn_mul_normal(rr->d, a->d, al, b->d, bl);\n#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)\n end:\n#endif\n    bn_correct_top(rr);\n    if (r != rr)\n        BN_copy(r, rr);\n    ret = 1;\n err:\n    bn_check_top(r);\n    BN_CTX_end(ctx);\n    return (ret);\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG_ENTRY("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_EXIT(ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']