int BN_set_word(BIGNUM *a, BN_ULONG w)
{
    bn_check_top(a);
    if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
        return (0);
    a->neg = 0;
    a->d[0] = w;
    a->top = (w ? 1 : 0);
    bn_check_top(a);
    return (1);
}
['int DH_check_pub_key(const DH *dh, const BIGNUM *pub_key, int *ret)\n{\n    int ok = 0;\n    BIGNUM *tmp = NULL;\n    BN_CTX *ctx = NULL;\n    *ret = 0;\n    ctx = BN_CTX_new();\n    if (ctx == NULL)\n        goto err;\n    BN_CTX_start(ctx);\n    tmp = BN_CTX_get(ctx);\n    if (tmp == NULL || !BN_set_word(tmp, 1))\n        goto err;\n    if (BN_cmp(pub_key, tmp) <= 0)\n        *ret |= DH_CHECK_PUBKEY_TOO_SMALL;\n    if (BN_copy(tmp, dh->p) == NULL || !BN_sub_word(tmp, 1))\n        goto err;\n    if (BN_cmp(pub_key, tmp) >= 0)\n        *ret |= DH_CHECK_PUBKEY_TOO_LARGE;\n    if (dh->q != NULL) {\n        if (!BN_mod_exp(tmp, pub_key, dh->q, dh->p, ctx))\n            goto err;\n        if (!BN_is_one(tmp))\n            *ret |= DH_CHECK_PUBKEY_INVALID;\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}', 'BIGNUM *BN_CTX_get(BN_CTX *ctx)\n{\n    BIGNUM *ret;\n    CTXDBG_ENTRY("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    ctx->used++;\n    CTXDBG_RET(ctx, ret);\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    bn_check_top(a);\n    return (1);\n}']