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;
}
['static int dh_test(void)\n{\n    BN_GENCB *_cb = NULL;\n    DH *a = NULL;\n    DH *b = NULL;\n    const BIGNUM *ap = NULL, *ag = NULL, *apub_key = NULL;\n    const BIGNUM *bpub_key = NULL;\n    BIGNUM *bp = NULL, *bg = NULL;\n    unsigned char *abuf = NULL;\n    unsigned char *bbuf = NULL;\n    int i, alen, blen, aout, bout;\n    int ret = 0;\n    RAND_seed(rnd_seed, sizeof rnd_seed);\n    if (!TEST_ptr(_cb = BN_GENCB_new()))\n        goto err;\n    BN_GENCB_set(_cb, &cb, NULL);\n    if (!TEST_ptr(a = DH_new())\n            || !TEST_true(DH_generate_parameters_ex(a, 64,\n                                                    DH_GENERATOR_5, _cb)))\n        goto err;\n    if (!DH_check(a, &i))\n        goto err;\n    if (!TEST_false(i & DH_CHECK_P_NOT_PRIME)\n            || !TEST_false(i & DH_CHECK_P_NOT_SAFE_PRIME)\n            || !TEST_false(i & DH_UNABLE_TO_CHECK_GENERATOR)\n            || !TEST_false(i & DH_NOT_SUITABLE_GENERATOR))\n        goto err;\n    DH_get0_pqg(a, &ap, NULL, &ag);\n    if (!TEST_ptr(b = DH_new()))\n        goto err;\n    if (!TEST_ptr(bp = BN_dup(ap))\n            || !TEST_ptr(bg = BN_dup(ag))\n            || !TEST_true(DH_set0_pqg(b, bp, NULL, bg)))\n        goto err;\n    bp = bg = NULL;\n    if (!DH_generate_key(a))\n        goto err;\n    DH_get0_key(a, &apub_key, NULL);\n    if (!DH_generate_key(b))\n        goto err;\n    DH_get0_key(b, &bpub_key, NULL);\n    alen = DH_size(a);\n    if (!TEST_ptr(abuf = OPENSSL_malloc(alen))\n            || !TEST_true((aout = DH_compute_key(abuf, bpub_key, a)) != -1))\n        goto err;\n    blen = DH_size(b);\n    if (!TEST_ptr(bbuf = OPENSSL_malloc(blen))\n            || !TEST_true((bout = DH_compute_key(bbuf, apub_key, b)) != -1))\n        goto err;\n    if (!TEST_true(aout >= 4)\n            || !TEST_mem_eq(abuf, aout, bbuf, bout))\n        goto err;\n    ret = 1;\n err:\n    OPENSSL_free(abuf);\n    OPENSSL_free(bbuf);\n    DH_free(b);\n    DH_free(a);\n    BN_free(bp);\n    BN_free(bg);\n    BN_GENCB_free(_cb);\n    return ret;\n}', 'int DH_generate_parameters_ex(DH *ret, int prime_len, int generator,\n                              BN_GENCB *cb)\n{\n    if (ret->meth->generate_params)\n        return ret->meth->generate_params(ret, prime_len, generator, cb);\n    return dh_builtin_genparams(ret, prime_len, generator, cb);\n}', 'int DH_check(const DH *dh, int *ret)\n{\n    int ok = 0, r;\n    BN_CTX *ctx = NULL;\n    BN_ULONG l;\n    BIGNUM *t1 = NULL, *t2 = NULL;\n    *ret = 0;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    t1 = BN_CTX_get(ctx);\n    if (t1 == NULL)\n        goto err;\n    t2 = BN_CTX_get(ctx);\n    if (t2 == NULL)\n        goto err;\n    if (dh->q) {\n        if (BN_cmp(dh->g, BN_value_one()) <= 0)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n        else if (BN_cmp(dh->g, dh->p) >= 0)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n        else {\n            if (!BN_mod_exp(t1, dh->g, dh->q, dh->p, ctx))\n                goto err;\n            if (!BN_is_one(t1))\n                *ret |= DH_NOT_SUITABLE_GENERATOR;\n        }\n        r = BN_is_prime_ex(dh->q, BN_prime_checks, ctx, NULL);\n        if (r < 0)\n            goto err;\n        if (!r)\n            *ret |= DH_CHECK_Q_NOT_PRIME;\n        if (!BN_div(t1, t2, dh->p, dh->q, ctx))\n            goto err;\n        if (!BN_is_one(t2))\n            *ret |= DH_CHECK_INVALID_Q_VALUE;\n        if (dh->j && BN_cmp(dh->j, t1))\n            *ret |= DH_CHECK_INVALID_J_VALUE;\n    } else if (BN_is_word(dh->g, DH_GENERATOR_2)) {\n        l = BN_mod_word(dh->p, 24);\n        if (l == (BN_ULONG)-1)\n            goto err;\n        if (l != 11)\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n    } else if (BN_is_word(dh->g, DH_GENERATOR_5)) {\n        l = BN_mod_word(dh->p, 10);\n        if (l == (BN_ULONG)-1)\n            goto err;\n        if ((l != 3) && (l != 7))\n            *ret |= DH_NOT_SUITABLE_GENERATOR;\n    } else\n        *ret |= DH_UNABLE_TO_CHECK_GENERATOR;\n    r = BN_is_prime_ex(dh->p, BN_prime_checks, ctx, NULL);\n    if (r < 0)\n        goto err;\n    if (!r)\n        *ret |= DH_CHECK_P_NOT_PRIME;\n    else if (!dh->q) {\n        if (!BN_rshift1(t1, dh->p))\n            goto err;\n        r = BN_is_prime_ex(t1, BN_prime_checks, ctx, NULL);\n        if (r < 0)\n            goto err;\n        if (!r)\n            *ret |= DH_CHECK_P_NOT_SAFE_PRIME;\n    }\n    ok = 1;\n err:\n    if (ctx != NULL) {\n        BN_CTX_end(ctx);\n        BN_CTX_free(ctx);\n    }\n    return (ok);\n}', 'int BN_cmp(const BIGNUM *a, const BIGNUM *b)\n{\n    int i;\n    int gt, lt;\n    BN_ULONG t1, t2;\n    if ((a == NULL) || (b == NULL)) {\n        if (a != NULL)\n            return (-1);\n        else if (b != NULL)\n            return (1);\n        else\n            return (0);\n    }\n    bn_check_top(a);\n    bn_check_top(b);\n    if (a->neg != b->neg) {\n        if (a->neg)\n            return (-1);\n        else\n            return (1);\n    }\n    if (a->neg == 0) {\n        gt = 1;\n        lt = -1;\n    } else {\n        gt = -1;\n        lt = 1;\n    }\n    if (a->top > b->top)\n        return (gt);\n    if (a->top < b->top)\n        return (lt);\n    for (i = a->top - 1; i >= 0; i--) {\n        t1 = a->d[i];\n        t2 = b->d[i];\n        if (t1 > t2)\n            return (gt);\n        if (t1 < t2)\n            return (lt);\n    }\n    return (0);\n}', 'int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    int ret;\n    bn_check_top(a);\n    bn_check_top(p);\n    bn_check_top(m);\n#define MONT_MUL_MOD\n#define MONT_EXP_WORD\n#define RECP_MUL_MOD\n#ifdef MONT_MUL_MOD\n    if (BN_is_odd(m)) {\n# ifdef MONT_EXP_WORD\n        if (a->top == 1 && !a->neg\n            && (BN_get_flags(p, BN_FLG_CONSTTIME) == 0)) {\n            BN_ULONG A = a->d[0];\n            ret = BN_mod_exp_mont_word(r, A, p, m, ctx, NULL);\n        } else\n# endif\n            ret = BN_mod_exp_mont(r, a, p, m, ctx, NULL);\n    } else\n#endif\n#ifdef RECP_MUL_MOD\n    {\n        ret = BN_mod_exp_recp(r, a, p, m, ctx);\n    }\n#else\n    {\n        ret = BN_mod_exp_simple(r, a, p, m, ctx);\n    }\n#endif\n    bn_check_top(r);\n    return (ret);\n}', 'int BN_is_odd(const BIGNUM *a)\n{\n    return (a->top > 0) && (a->d[0] & 1);\n}', 'int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,\n                    const BIGNUM *m, BN_CTX *ctx)\n{\n    int i, j, bits, ret = 0, wstart, wend, window, wvalue;\n    int start = 1;\n    BIGNUM *aa;\n    BIGNUM *val[TABLE_SIZE];\n    BN_RECP_CTX recp;\n    if (BN_get_flags(p, BN_FLG_CONSTTIME) != 0) {\n        BNerr(BN_F_BN_MOD_EXP_RECP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);\n        return 0;\n    }\n    bits = BN_num_bits(p);\n    if (bits == 0) {\n        if (BN_is_one(m)) {\n            ret = 1;\n            BN_zero(r);\n        } else {\n            ret = BN_one(r);\n        }\n        return ret;\n    }\n    BN_CTX_start(ctx);\n    aa = BN_CTX_get(ctx);\n    val[0] = BN_CTX_get(ctx);\n    if (!aa || !val[0])\n        goto err;\n    BN_RECP_CTX_init(&recp);\n    if (m->neg) {\n        if (!BN_copy(aa, m))\n            goto err;\n        aa->neg = 0;\n        if (BN_RECP_CTX_set(&recp, aa, ctx) <= 0)\n            goto err;\n    } else {\n        if (BN_RECP_CTX_set(&recp, m, ctx) <= 0)\n            goto err;\n    }\n    if (!BN_nnmod(val[0], a, m, ctx))\n        goto err;\n    if (BN_is_zero(val[0])) {\n        BN_zero(r);\n        ret = 1;\n        goto err;\n    }\n    window = BN_window_bits_for_exponent_size(bits);\n    if (window > 1) {\n        if (!BN_mod_mul_reciprocal(aa, val[0], val[0], &recp, ctx))\n            goto err;\n        j = 1 << (window - 1);\n        for (i = 1; i < j; i++) {\n            if (((val[i] = BN_CTX_get(ctx)) == NULL) ||\n                !BN_mod_mul_reciprocal(val[i], val[i - 1], aa, &recp, ctx))\n                goto err;\n        }\n    }\n    start = 1;\n    wvalue = 0;\n    wstart = bits - 1;\n    wend = 0;\n    if (!BN_one(r))\n        goto err;\n    for (;;) {\n        if (BN_is_bit_set(p, wstart) == 0) {\n            if (!start)\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            if (wstart == 0)\n                break;\n            wstart--;\n            continue;\n        }\n        j = wstart;\n        wvalue = 1;\n        wend = 0;\n        for (i = 1; i < window; i++) {\n            if (wstart - i < 0)\n                break;\n            if (BN_is_bit_set(p, wstart - i)) {\n                wvalue <<= (i - wend);\n                wvalue |= 1;\n                wend = i;\n            }\n        }\n        j = wend + 1;\n        if (!start)\n            for (i = 0; i < j; i++) {\n                if (!BN_mod_mul_reciprocal(r, r, r, &recp, ctx))\n                    goto err;\n            }\n        if (!BN_mod_mul_reciprocal(r, r, val[wvalue >> 1], &recp, ctx))\n            goto err;\n        wstart -= wend + 1;\n        wvalue = 0;\n        start = 0;\n        if (wstart < 0)\n            break;\n    }\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    BN_RECP_CTX_free(&recp);\n    bn_check_top(r);\n    return (ret);\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}']