The Ring

idahowalker
Posts: 131
Joined: Wed Aug 01, 2018 12:06 pm

The Ring

Postby idahowalker » Fri Nov 08, 2019 4:52 pm

Buffer.

My current thing do is about using a Ring Buffer.

Code: Select all

void fSendSerialToBrain( void *pvParameters )
{
  CAN_frame_t rx_frame;
  xSemaphoreGive ( sema_SendSerialToBrain );
  bool PassTwo = false;
  for (;;)
  {
    xEventGroupWaitBits (eg, evtSendSerialToBrain, pdTRUE, pdTRUE, portMAX_DELAY);
    size_t item_size;
    for (int i = 0; i < RingBufferTriggerSize; i++)
    {
      int *item = (int *)xRingbufferReceive(h_buf_LIDAR_INFO, &item_size, pdMS_TO_TICKS(0)); // reterive item from ring buffer, no wait
      if (item != NULL)
      {
        vRingbufferReturnItem(h_buf_LIDAR_INFO, (void *)item); // remove item from ring buffer
        // prep item for sending over CAN buss
        if (!PassTwo)
        {
          rx_frame.FIR.B.FF = CAN_frame_std;
          rx_frame.MsgID = 1;
          rx_frame.FIR.B.DLC = 8;
          rx_frame.data.u8[0] = *item & 0xFF;
          rx_frame.data.u8[1] = (*item >> 8) & 0xFF;
          rx_frame.data.u8[2] = (*item >> 16) & 0xFF;
          rx_frame.data.u8[3] = (*item >> 24) & 0xFF;
          PassTwo = true;
        } else {
          rx_frame.data.u8[4] = *item & 0xFF;;
          rx_frame.data.u8[5] = (*item >> 8) & 0xFF;
          rx_frame.data.u8[6] = (*item >> 16) & 0xFF;
          rx_frame.data.u8[7] = (*item >> 24) & 0xFF;
          ESP32Can.CANWriteFrame(&rx_frame); // send items over CAN buss
          PassTwo = false;
        }
      }
    }
  }
  vTaskDelete( NULL );
} // void fSendSerialToBrain( void *pvParameters )
I know how to get the data on the pointer info.

What I'd like to do, if possible, is to read the entire contents of the ring buffer but only remove the first item, instead of removing all the items. I am under the impression that each retrieve requires a vRingbufferReturnItem. It makes sense to me that if I just do a vRingbufferReturnItem on the first item that the first item can be replaced leaving the other items in place but still able to be read?

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