Function SDL_WriteToDataQueue

deps/SDL2/src/SDL_dataqueue.c:174–226

int
SDL_WriteToDataQueue(SDL_DataQueue *queue, const void *_data, const size_t _len)
{
    size_t len = _len;
    const Uint8 *data = (const Uint8 *) _data;
    const size_t packet_size = queue ? queue->packet_size : 0;
    SDL_DataQueuePacket *orighead;
    SDL_DataQueuePacket *origtail;
    size_t origlen;
    size_t datalen;

    if (!queue) {
        return SDL_InvalidParamError("queue");
    }

    orighead = queue->head;
    origtail = queue->tail;
    origlen = origtail ? origtail->datalen : 0;

    while (len > 0) {
        SDL_DataQueuePacket *packet = queue->tail;
        SDL_assert(!packet || (packet->datalen <= packet_size));
        if (!packet || (packet->datalen >= packet_size)) {
            /* tail packet missing or completely full; we need a new packet. */
            packet = AllocateDataQueuePacket(queue);
            if (!packet) {
                /* uhoh, reset so we've queued nothing new, free what we can. */
                if (!origtail) {
                    packet = queue->head;  /* whole queue. */
                } else {
                    packet = origtail->next;  /* what we added to existing queue. */
                    origtail->next = NULL;
                    origtail->datalen = origlen;
                }
                queue->head = orighead;
                queue->tail = origtail;
                queue->pool = NULL;

                SDL_FreeDataQueueList(packet);  /* give back what we can. */
                return SDL_OutOfMemory();
            }
        }

        datalen = SDL_min(len, packet_size - packet->datalen);
        SDL_memcpy(packet->data + packet->datalen, data, datalen);
        data += datalen;
        len -= datalen;
        packet->datalen += datalen;
        queue->queued_bytes += datalen;
    }

    return 0;
}

size_t
SDL_PeekIntoDataQueue(SDL_DataQueue *queue, void *_buf, const size_t _len)