int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)
{
    assert(pkt->subs != NULL && len != 0);
    if (pkt->subs == NULL || len == 0)
        return 0;
    if (pkt->maxsize - pkt->written < len)
        return 0;
    if (pkt->buf->length - pkt->written < len) {
        size_t newlen;
        size_t reflen;
        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;
        if (reflen > SIZE_MAX / 2) {
            newlen = SIZE_MAX;
        } else {
            newlen = reflen * 2;
            if (newlen < DEFAULT_BUF_SIZE)
                newlen = DEFAULT_BUF_SIZE;
        }
        if (BUF_MEM_grow(pkt->buf, newlen) == 0)
            return 0;
    }
    *allocbytes = (unsigned char *)pkt->buf->data + pkt->curr;
    return 1;
}
['static int tls_construct_cke_dhe(SSL *s, WPACKET *pkt, int *al)\n{\n#ifndef OPENSSL_NO_DH\n    DH *dh_clnt = NULL;\n    const BIGNUM *pub_key;\n    EVP_PKEY *ckey = NULL, *skey = NULL;\n    unsigned char *keybytes = NULL;\n    skey = s->s3->peer_tmp;\n    if (skey == NULL)\n        goto err;\n    ckey = ssl_generate_pkey(skey);\n    dh_clnt = EVP_PKEY_get0_DH(ckey);\n    if (dh_clnt == NULL || ssl_derive(s, ckey, skey) == 0)\n        goto err;\n    DH_get0_key(dh_clnt, &pub_key, NULL);\n    if (!WPACKET_sub_allocate_bytes_u16(pkt, BN_num_bytes(pub_key), &keybytes))\n        goto err;\n    BN_bn2bin(pub_key, keybytes);\n    EVP_PKEY_free(ckey);\n    return 1;\n err:\n    EVP_PKEY_free(ckey);\n#endif\n    SSLerr(SSL_F_TLS_CONSTRUCT_CKE_DHE, ERR_R_INTERNAL_ERROR);\n    *al = SSL_AD_INTERNAL_ERROR;\n    return 0;\n}', 'int WPACKET_sub_allocate_bytes__(WPACKET *pkt, size_t len,\n                                 unsigned char **allocbytes, size_t lenbytes)\n{\n    if (!WPACKET_start_sub_packet_len__(pkt, lenbytes)\n            || !WPACKET_allocate_bytes(pkt, len, allocbytes)\n            || !WPACKET_close(pkt))\n        return 0;\n    return 1;\n}', 'int WPACKET_start_sub_packet_len__(WPACKET *pkt, size_t lenbytes)\n{\n    WPACKET_SUB *sub;\n    unsigned char *lenchars;\n    assert(pkt->subs != NULL);\n    if (pkt->subs == NULL)\n        return 0;\n    sub = OPENSSL_zalloc(sizeof(*sub));\n    if (sub == NULL)\n        return 0;\n    sub->parent = pkt->subs;\n    pkt->subs = sub;\n    sub->pwritten = pkt->written + lenbytes;\n    sub->lenbytes = lenbytes;\n    if (lenbytes == 0) {\n        sub->packet_len = 0;\n        return 1;\n    }\n    if (!WPACKET_allocate_bytes(pkt, lenbytes, &lenchars))\n        return 0;\n    sub->packet_len = lenchars - (unsigned char *)pkt->buf->data;\n    return 1;\n}', 'int WPACKET_allocate_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)\n{\n    if (!WPACKET_reserve_bytes(pkt, len, allocbytes))\n        return 0;\n    pkt->written += len;\n    pkt->curr += len;\n    return 1;\n}', 'int WPACKET_reserve_bytes(WPACKET *pkt, size_t len, unsigned char **allocbytes)\n{\n    assert(pkt->subs != NULL && len != 0);\n    if (pkt->subs == NULL || len == 0)\n        return 0;\n    if (pkt->maxsize - pkt->written < len)\n        return 0;\n    if (pkt->buf->length - pkt->written < len) {\n        size_t newlen;\n        size_t reflen;\n        reflen = (len > pkt->buf->length) ? len : pkt->buf->length;\n        if (reflen > SIZE_MAX / 2) {\n            newlen = SIZE_MAX;\n        } else {\n            newlen = reflen * 2;\n            if (newlen < DEFAULT_BUF_SIZE)\n                newlen = DEFAULT_BUF_SIZE;\n        }\n        if (BUF_MEM_grow(pkt->buf, newlen) == 0)\n            return 0;\n    }\n    *allocbytes = (unsigned char *)pkt->buf->data + pkt->curr;\n    return 1;\n}']