void* MQTTPacket_publish(unsigned char aHeader, char* data, size_t datalen)
{
Publish* pack = malloc(sizeof(Publish));
char* curdata = data;
char* enddata = &data[datalen];
FUNC_ENTRY;
pack->header.byte = aHeader;
if ((pack->topic = readUTFlen(&curdata, enddata, &pack->topiclen)) == NULL) // Topic name on which to publish.
{
free(pack);
pack = NULL;
goto exit;
}
if (pack->header.bits.qos > 0) // Msgid only exists for QoS 1 or 2
pack->msgId = readInt(&curdata);
else
pack->msgId = 0;
pack->payload = curdata;
pack->payloadlen = datalen-(curdata-data);
exit:
FUNC_EXIT;
return pack;
}
/**
* Reads a "UTF" string from the input buffer. UTF as in the MQTT v3 spec which really means
* a length delimited string. So it reads the two byte length then the data according to
* that length. The end of the buffer is provided too, so we can prevent buffer overruns caused
* by an incorrect length.
* @param pptr pointer to the input buffer - incremented by the number of bytes used & returned
* @param enddata pointer to the end of the buffer not to be read beyond
* @return an allocated C string holding the characters read, or NULL if the length read would
* have caused an overrun.
*/
char* readUTF(char** pptr, char* enddata)
{
int len;
return readUTFlen(pptr, enddata, &len);
}