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esp-idf/components/freertos/ringbuf.c

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C
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// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdlib.h>
#include <string.h>
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
#include "ringbuf.h"
//32-bit alignment macros
#define rbALIGN_SIZE( xSize ) ( ( xSize + portBYTE_ALIGNMENT_MASK ) & ~portBYTE_ALIGNMENT_MASK )
#define rbCHECK_ALIGNED( pvPtr ) ( ( ( UBaseType_t ) pvPtr & portBYTE_ALIGNMENT_MASK ) == 0 )
//Ring buffer flags
#define rbALLOW_SPLIT_FLAG ( ( UBaseType_t ) 1 ) //The ring buffer allows items to be split
#define rbBYTE_BUFFER_FLAG ( ( UBaseType_t ) 2 ) //The ring buffer is a byte buffer
#define rbBUFFER_FULL_FLAG ( ( UBaseType_t ) 4 ) //The ring buffer is currently full (write pointer == free pointer)
//Item flags
#define rbITEM_FREE_FLAG ( ( UBaseType_t ) 1 ) //Item has been retrieved and returned by application, free to overwrite
#define rbITEM_DUMMY_DATA_FLAG ( ( UBaseType_t ) 2 ) //Data from here to end of the ring buffer is dummy data. Restart reading at start of head of the buffer
#define rbITEM_SPLIT_FLAG ( ( UBaseType_t ) 4 ) //Valid for RINGBUF_TYPE_ALLOWSPLIT, indicating that rest of the data is wrapped around
typedef struct {
//This size of this structure must be 32-bit aligned
size_t xItemLen;
UBaseType_t uxItemFlags;
} ItemHeader_t;
#define rbHEADER_SIZE sizeof(ItemHeader_t)
typedef struct Ringbuffer_t Ringbuffer_t;
typedef BaseType_t (*CheckItemFitsFunction_t)(Ringbuffer_t *pxRingbuffer, size_t xItemSize);
typedef void (*CopyItemFunction_t)(Ringbuffer_t *pxRingbuffer, const uint8_t *pcItem, size_t xItemSize);
typedef BaseType_t (*CheckItemAvailFunction_t) (Ringbuffer_t *pxRingbuffer);
typedef void *(*GetItemFunction_t)(Ringbuffer_t *pxRingbuffer, BaseType_t *pxIsSplit, size_t xMaxSize, size_t *pxItemSize);
typedef void (*ReturnItemFunction_t)(Ringbuffer_t *pxRingbuffer, uint8_t *pvItem);
typedef size_t (*GetCurMaxSizeFunction_t)(Ringbuffer_t *pxRingbuffer);
struct Ringbuffer_t {
size_t xSize; //Size of the data storage
UBaseType_t uxRingbufferFlags; //Flags to indicate the type and status of ring buffer
size_t xMaxItemSize; //Maximum item size
CheckItemFitsFunction_t xCheckItemFits; //Function to check if item can currently fit in ring buffer
CopyItemFunction_t vCopyItem; //Function to copy item to ring buffer
GetItemFunction_t pvGetItem; //Function to get item from ring buffer
ReturnItemFunction_t vReturnItem; //Function to return item to ring buffer
GetCurMaxSizeFunction_t xGetCurMaxSize; //Function to get current free size
uint8_t *pucWrite; //Write Pointer. Points to where the next item should be written
uint8_t *pucRead; //Read Pointer. Points to where the next item should be read from
uint8_t *pucFree; //Free Pointer. Points to the last item that has yet to be returned to the ring buffer
uint8_t *pucHead; //Pointer to the start of the ring buffer storage area
uint8_t *pucTail; //Pointer to the end of the ring buffer storage area
BaseType_t xItemsWaiting; //Number of items/bytes(for byte buffers) currently in ring buffer that have not yet been read
SemaphoreHandle_t xFreeSpaceSemaphore; //Binary semaphore, wakes up writing threads when more free space becomes available or when another thread times out attempting to write
SemaphoreHandle_t xItemsBufferedSemaphore; //Binary semaphore, indicates there are new packets in the circular buffer. See remark.
portMUX_TYPE mux; //Spinlock required for SMP
};
/*
Remark: A counting semaphore for items_buffered_sem would be more logical, but counting semaphores in
FreeRTOS need a maximum count, and allocate more memory the larger the maximum count is. Here, we
would need to set the maximum to the maximum amount of times a null-byte unit first in the buffer,
which is quite high and so would waste a fair amount of memory.
*/
/* ------------------------------------------------ Static Declarations ------------------------------------------ */
/*
* WARNING: All of the following static functions (except generic functions)
* ARE NOT THREAD SAFE. Therefore they should only be called within a critical
* section (using spin locks)
*/
//Calculate current amount of free space (in bytes) in the ring buffer
static size_t prvGetFreeSize(Ringbuffer_t *pxRingbuffer);
//Checks if an item/data is currently available for retrieval
static BaseType_t prvCheckItemAvail(Ringbuffer_t *pxRingbuffer);
//Checks if an item will currently fit in a no-split/allow-split ring buffer
static BaseType_t prvCheckItemFitsDefault( Ringbuffer_t *pxRingbuffer, size_t xItemSize);
//Checks if an item will currently fit in a byte buffer
static BaseType_t prvCheckItemFitsByteBuffer( Ringbuffer_t *pxRingbuffer, size_t xItemSize);
//Copies an item to a no-split ring buffer. Only call this function after calling prvCheckItemFitsDefault()
static void prvCopyItemNoSplit(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize);
//Copies an item to a allow-split ring buffer. Only call this function after calling prvCheckItemFitsDefault()
static void prvCopyItemAllowSplit(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize);
//Copies an item to a byte buffer. Only call this function after calling prvCheckItemFitsByteBuffer()
static void prvCopyItemByteBuf(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize);
//Retrieve item from no-split/allow-split ring buffer. *pxIsSplit is set to pdTRUE if the retrieved item is split
static void *prvGetItemDefault(Ringbuffer_t *pxRingbuffer, BaseType_t *pxIsSplit, size_t xUnusedParam, size_t *pxItemSize);
//Retrieve data from byte buffer. If xMaxSize is 0, all continuous data is retrieved
static void *prvGetItemByteBuf(Ringbuffer_t *pxRingbuffer, BaseType_t *pxUnusedParam ,size_t xMaxSize, size_t *pxItemSize);
//Return an item to a split/no-split ring buffer
static void prvReturnItemDefault(Ringbuffer_t *pxRingbuffer, uint8_t *pucItem);
//Return data to a byte buffer
static void prvReturnItemByteBuf(Ringbuffer_t *pxRingbuffer, uint8_t *pucItem);
//Get the maximum size an item that can currently have if sent to a no-split ring buffer
static size_t prvGetCurMaxSizeNoSplit(Ringbuffer_t *pxRingbuffer);
//Get the maximum size an item that can currently have if sent to a allow-split ring buffer
static size_t prvGetCurMaxSizeAllowSplit(Ringbuffer_t *pxRingbuffer);
//Get the maximum size an item that can currently have if sent to a byte buffer
static size_t prvGetCurMaxSizeByteBuf(Ringbuffer_t *pxRingbuffer);
/**
* Generic function used to retrieve an item/data from ring buffers. If called on
* an allow-split buffer, and pvItem2 and xItemSize2 are not NULL, both parts of
* a split item will be retrieved. xMaxSize will only take effect if called on
* byte buffers.
*/
static BaseType_t prvReceiveGeneric(Ringbuffer_t *pxRingbuffer, void **pvItem1, void **pvItem2, size_t *xItemSize1, size_t *xItemSize2, size_t xMaxSize, TickType_t xTicksToWait);
//Generic function used to retrieve an item/data from ring buffers in an ISR
static BaseType_t prvReceiveGenericFromISR(Ringbuffer_t *pxRingbuffer, void **pvItem1, void **pvItem2, size_t *xItemSize1, size_t *xItemSize2, size_t xMaxSize);
/* ------------------------------------------------ Static Definitions ------------------------------------------- */
static size_t prvGetFreeSize(Ringbuffer_t *pxRingbuffer)
{
size_t xReturn;
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
xReturn = 0;
} else {
BaseType_t xFreeSize = pxRingbuffer->pucFree - pxRingbuffer->pucWrite;
//Check if xFreeSize has underflowed
if (xFreeSize <= 0) {
xFreeSize += pxRingbuffer->xSize;
}
xReturn = xFreeSize;
}
configASSERT(xReturn <= pxRingbuffer->xSize);
return xReturn;
}
static BaseType_t prvCheckItemFitsDefault( Ringbuffer_t *pxRingbuffer, size_t xItemSize)
{
//Check arguments and buffer state
configASSERT(rbCHECK_ALIGNED(pxRingbuffer->pucWrite)); //pucWrite is always aligned in no-split ring buffers
configASSERT(pxRingbuffer->pucWrite >= pxRingbuffer->pucHead && pxRingbuffer->pucWrite < pxRingbuffer->pucTail); //Check write pointer is within bounds
size_t xTotalItemSize = rbALIGN_SIZE(xItemSize) + rbHEADER_SIZE; //Rounded up aligned item size with header
if (pxRingbuffer->pucWrite == pxRingbuffer->pucFree) {
//Buffer is either complete empty or completely full
return (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) ? pdFALSE : pdTRUE;
}
if (pxRingbuffer->pucFree > pxRingbuffer->pucWrite) {
//Free space does not wrap around
return (xTotalItemSize <= pxRingbuffer->pucFree - pxRingbuffer->pucWrite) ? pdTRUE : pdFALSE;
}
//Free space wraps around
if (xTotalItemSize <= pxRingbuffer->pucTail - pxRingbuffer->pucWrite) {
return pdTRUE; //Item fits without wrapping around
}
//Check if item fits by wrapping
if (pxRingbuffer->uxRingbufferFlags & rbALLOW_SPLIT_FLAG) {
//Allow split wrapping incurs an extra header
return (xTotalItemSize + rbHEADER_SIZE <= pxRingbuffer->xSize - (pxRingbuffer->pucWrite - pxRingbuffer->pucFree)) ? pdTRUE : pdFALSE;
} else {
return (xTotalItemSize <= pxRingbuffer->pucFree - pxRingbuffer->pucHead) ? pdTRUE : pdFALSE;
}
}
static BaseType_t prvCheckItemFitsByteBuffer( Ringbuffer_t *pxRingbuffer, size_t xItemSize)
{
//Check arguments and buffer state
configASSERT(pxRingbuffer->pucWrite >= pxRingbuffer->pucHead && pxRingbuffer->pucWrite < pxRingbuffer->pucTail); //Check write pointer is within bounds
if (pxRingbuffer->pucWrite == pxRingbuffer->pucFree) {
//Buffer is either complete empty or completely full
return (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) ? pdFALSE : pdTRUE;
}
if (pxRingbuffer->pucFree > pxRingbuffer->pucWrite) {
//Free space does not wrap around
return (xItemSize <= pxRingbuffer->pucFree - pxRingbuffer->pucWrite) ? pdTRUE : pdFALSE;
}
//Free space wraps around
return (xItemSize <= pxRingbuffer->xSize - (pxRingbuffer->pucWrite - pxRingbuffer->pucFree)) ? pdTRUE : pdFALSE;
}
static void prvCopyItemNoSplit(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize)
{
//Check arguments and buffer state
size_t xAlignedItemSize = rbALIGN_SIZE(xItemSize); //Rounded up aligned item size
size_t xRemLen = pxRingbuffer->pucTail - pxRingbuffer->pucWrite; //Length from pucWrite until end of buffer
configASSERT(rbCHECK_ALIGNED(pxRingbuffer->pucWrite)); //pucWrite is always aligned in no-split ring buffers
configASSERT(pxRingbuffer->pucWrite >= pxRingbuffer->pucHead && pxRingbuffer->pucWrite < pxRingbuffer->pucTail); //Check write pointer is within bounds
configASSERT(xRemLen >= rbHEADER_SIZE); //Remaining length must be able to at least fit an item header
//If remaining length can't fit item, set as dummy data and wrap around
if (xRemLen < xAlignedItemSize + rbHEADER_SIZE) {
ItemHeader_t *pxDummy = (ItemHeader_t *)pxRingbuffer->pucWrite;
pxDummy->uxItemFlags = rbITEM_DUMMY_DATA_FLAG; //Set remaining length as dummy data
pxDummy->xItemLen = 0; //Dummy data should have no length
pxRingbuffer->pucWrite = pxRingbuffer->pucHead; //Reset write pointer to wrap around
}
//Item should be guaranteed to fit at this point. Set item header and copy data
ItemHeader_t *pxHeader = (ItemHeader_t *)pxRingbuffer->pucWrite;
pxHeader->xItemLen = xItemSize;
pxHeader->uxItemFlags = 0;
pxRingbuffer->pucWrite += rbHEADER_SIZE; //Advance pucWrite past header
memcpy(pxRingbuffer->pucWrite, pucItem, xItemSize);
pxRingbuffer->xItemsWaiting++;
pxRingbuffer->pucWrite += xAlignedItemSize; //Advance pucWrite past item to next aligned address
//If current remaining length can't fit a header, wrap around write pointer
if (pxRingbuffer->pucTail - pxRingbuffer->pucWrite < rbHEADER_SIZE) {
pxRingbuffer->pucWrite = pxRingbuffer->pucHead; //Wrap around pucWrite
}
//Check if buffer is full
if (pxRingbuffer->pucWrite == pxRingbuffer->pucFree) {
//Mark the buffer as full to distinguish with an empty buffer
pxRingbuffer->uxRingbufferFlags |= rbBUFFER_FULL_FLAG;
}
}
static void prvCopyItemAllowSplit(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize)
{
//Check arguments and buffer state
size_t xAlignedItemSize = rbALIGN_SIZE(xItemSize); //Rounded up aligned item size
size_t xRemLen = pxRingbuffer->pucTail - pxRingbuffer->pucWrite; //Length from pucWrite until end of buffer
configASSERT(rbCHECK_ALIGNED(pxRingbuffer->pucWrite)); //pucWrite is always aligned in split ring buffers
configASSERT(pxRingbuffer->pucWrite >= pxRingbuffer->pucHead && pxRingbuffer->pucWrite < pxRingbuffer->pucTail); //Check write pointer is within bounds
configASSERT(xRemLen >= rbHEADER_SIZE); //Remaining length must be able to at least fit an item header
//Split item if necessary
if (xRemLen < xAlignedItemSize + rbHEADER_SIZE) {
//Write first part of the item
ItemHeader_t *pxFirstHeader = (ItemHeader_t *)pxRingbuffer->pucWrite;
pxFirstHeader->uxItemFlags = 0;
pxFirstHeader->xItemLen = xRemLen - rbHEADER_SIZE; //Fill remaining length with first part
pxRingbuffer->pucWrite += rbHEADER_SIZE; //Advance pucWrite past header
xRemLen -= rbHEADER_SIZE;
if (xRemLen > 0) {
memcpy(pxRingbuffer->pucWrite, pucItem, xRemLen);
pxRingbuffer->xItemsWaiting++;
//Update item arguments to account for data already copied
pucItem += xRemLen;
xItemSize -= xRemLen;
xAlignedItemSize -= xRemLen;
pxFirstHeader->uxItemFlags |= rbITEM_SPLIT_FLAG; //There must be more data
} else {
//Remaining length was only large enough to fit header
pxFirstHeader->uxItemFlags |= rbITEM_DUMMY_DATA_FLAG; //Item will completely be stored in 2nd part
}
pxRingbuffer->pucWrite = pxRingbuffer->pucHead; //Reset write pointer to start of buffer
}
//Item (whole or second part) should be guaranteed to fit at this point
ItemHeader_t *pxSecondHeader = (ItemHeader_t *)pxRingbuffer->pucWrite;
pxSecondHeader->xItemLen = xItemSize;
pxSecondHeader->uxItemFlags = 0;
pxRingbuffer->pucWrite += rbHEADER_SIZE; //Advance write pointer past header
memcpy(pxRingbuffer->pucWrite, pucItem, xItemSize);
pxRingbuffer->xItemsWaiting++;
pxRingbuffer->pucWrite += xAlignedItemSize; //Advance pucWrite past item to next aligned address
//If current remaining length can't fit a header, wrap around write pointer
if (pxRingbuffer->pucTail - pxRingbuffer->pucWrite < rbHEADER_SIZE) {
pxRingbuffer->pucWrite = pxRingbuffer->pucHead; //Wrap around pucWrite
}
//Check if buffer is full
if (pxRingbuffer->pucWrite == pxRingbuffer->pucFree) {
//Mark the buffer as full to distinguish with an empty buffer
pxRingbuffer->uxRingbufferFlags |= rbBUFFER_FULL_FLAG;
}
}
static void prvCopyItemByteBuf(Ringbuffer_t *pxRingbuffer, const uint8_t *pucItem, size_t xItemSize)
{
//Check arguments and buffer state
configASSERT(pxRingbuffer->pucWrite >= pxRingbuffer->pucHead && pxRingbuffer->pucWrite < pxRingbuffer->pucTail); //Check write pointer is within bounds
size_t xRemLen = pxRingbuffer->pucTail - pxRingbuffer->pucWrite; //Length from pucWrite until end of buffer
if (xRemLen < xItemSize) {
//Copy as much as possible into remaining length
memcpy(pxRingbuffer->pucWrite, pucItem, xRemLen);
pxRingbuffer->xItemsWaiting += xRemLen;
//Update item arguments to account for data already written
pucItem += xRemLen;
xItemSize -= xRemLen;
pxRingbuffer->pucWrite = pxRingbuffer->pucHead; //Reset write pointer to start of buffer
}
//Copy all or remaining portion of the item
memcpy(pxRingbuffer->pucWrite, pucItem, xItemSize);
pxRingbuffer->xItemsWaiting += xItemSize;
pxRingbuffer->pucWrite += xItemSize;
//Wrap around pucWrite if it reaches the end
if (pxRingbuffer->pucWrite == pxRingbuffer->pucTail) {
pxRingbuffer->pucWrite = pxRingbuffer->pucHead;
}
//Check if buffer is full
if (pxRingbuffer->pucWrite == pxRingbuffer->pucFree) {
pxRingbuffer->uxRingbufferFlags |= rbBUFFER_FULL_FLAG; //Mark the buffer as full to avoid confusion with an empty buffer
}
}
static BaseType_t prvCheckItemAvail(Ringbuffer_t *pxRingbuffer)
{
if ((pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG) && pxRingbuffer->pucRead != pxRingbuffer->pucFree) {
return pdFALSE; //Byte buffers do not allow multiple retrievals before return
}
if ((pxRingbuffer->xItemsWaiting > 0) && ((pxRingbuffer->pucRead != pxRingbuffer->pucWrite) || (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG))) {
return pdTRUE; //Items/data available for retrieval
} else {
return pdFALSE; //No items/data available for retrieval
}
}
static void *prvGetItemDefault(Ringbuffer_t *pxRingbuffer, BaseType_t *pxIsSplit, size_t xUnusedParam, size_t *pxItemSize)
{
//Check arguments and buffer state
ItemHeader_t *pxHeader = (ItemHeader_t *)pxRingbuffer->pucRead;
configASSERT(pxIsSplit != NULL);
configASSERT((pxRingbuffer->xItemsWaiting > 0) && ((pxRingbuffer->pucRead != pxRingbuffer->pucWrite) || (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG))); //Check there are items to be read
configASSERT(rbCHECK_ALIGNED(pxRingbuffer->pucRead)); //pucRead is always aligned in split ring buffers
configASSERT(pxRingbuffer->pucRead >= pxRingbuffer->pucHead && pxRingbuffer->pucRead < pxRingbuffer->pucTail); //Check read pointer is within bounds
configASSERT((pxHeader->xItemLen <= pxRingbuffer->xMaxItemSize) || (pxHeader->uxItemFlags & rbITEM_DUMMY_DATA_FLAG));
uint8_t *pcReturn;
//Wrap around if dummy data (dummy data indicates wrap around in no-split buffers)
if (pxHeader->uxItemFlags & rbITEM_DUMMY_DATA_FLAG) {
pxRingbuffer->pucRead = pxRingbuffer->pucHead;
//Check for errors with the next item
pxHeader = (ItemHeader_t *)pxRingbuffer->pucRead;
configASSERT(pxHeader->xItemLen <= pxRingbuffer->xMaxItemSize);
}
pcReturn = pxRingbuffer->pucRead + rbHEADER_SIZE; //Get pointer to part of item containing data (point past the header)
if (pxHeader->xItemLen == 0) {
//Inclusive of pucTail for special case where item of zero length just fits at the end of the buffer
configASSERT(pcReturn >= pxRingbuffer->pucHead && pcReturn <= pxRingbuffer->pucTail);
} else {
//Exclusive of pucTali if length is larger than zero, pcReturn should never point to pucTail
configASSERT(pcReturn >= pxRingbuffer->pucHead && pcReturn < pxRingbuffer->pucTail);
}
*pxItemSize = pxHeader->xItemLen; //Get length of item
pxRingbuffer->xItemsWaiting --; //Update item count
*pxIsSplit = (pxHeader->uxItemFlags & rbITEM_SPLIT_FLAG) ? pdTRUE : pdFALSE;
pxRingbuffer->pucRead += rbHEADER_SIZE + rbALIGN_SIZE(pxHeader->xItemLen); //Update pucRead
//Check if pucRead requires wrap around
if ((pxRingbuffer->pucTail - pxRingbuffer->pucRead) < rbHEADER_SIZE) {
pxRingbuffer->pucRead = pxRingbuffer->pucHead;
}
return (void *)pcReturn;
}
static void *prvGetItemByteBuf(Ringbuffer_t *pxRingbuffer, BaseType_t *pxUnusedParam ,size_t xMaxSize, size_t *pxItemSize)
{
//Check arguments and buffer state
configASSERT((pxRingbuffer->xItemsWaiting > 0) && ((pxRingbuffer->pucRead != pxRingbuffer->pucWrite) || (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG))); //Check there are items to be read
configASSERT(pxRingbuffer->pucRead >= pxRingbuffer->pucHead && pxRingbuffer->pucRead < pxRingbuffer->pucTail); //Check read pointer is within bounds
configASSERT(pxRingbuffer->pucRead == pxRingbuffer->pucFree);
uint8_t *ret = pxRingbuffer->pucRead;
if ((pxRingbuffer->pucRead > pxRingbuffer->pucWrite) || (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG)) { //Available data wraps around
//Return contiguous piece from read pointer until buffer tail, or xMaxSize
if (xMaxSize == 0 || pxRingbuffer->pucTail - pxRingbuffer->pucRead <= xMaxSize) {
//All contiguous data from read pointer to tail
*pxItemSize = pxRingbuffer->pucTail - pxRingbuffer->pucRead;
pxRingbuffer->xItemsWaiting -= pxRingbuffer->pucTail - pxRingbuffer->pucRead;
pxRingbuffer->pucRead = pxRingbuffer->pucHead; //Wrap around read pointer
} else {
//Return xMaxSize amount of data
*pxItemSize = xMaxSize;
pxRingbuffer->xItemsWaiting -= xMaxSize;
pxRingbuffer->pucRead += xMaxSize; //Advance read pointer past retrieved data
}
} else { //Available data is contiguous between read and write pointer
if (xMaxSize == 0 || pxRingbuffer->pucWrite - pxRingbuffer->pucRead <= xMaxSize) {
//Return all contiguous data from read to write pointer
*pxItemSize = pxRingbuffer->pucWrite - pxRingbuffer->pucRead;
pxRingbuffer->xItemsWaiting -= pxRingbuffer->pucWrite - pxRingbuffer->pucRead;
pxRingbuffer->pucRead = pxRingbuffer->pucWrite;
} else {
//Return xMaxSize data from read pointer
*pxItemSize = xMaxSize;
pxRingbuffer->xItemsWaiting -= xMaxSize;
pxRingbuffer->pucRead += xMaxSize; //Advance read pointer past retrieved data
}
}
return (void *)ret;
}
static void prvReturnItemDefault(Ringbuffer_t *pxRingbuffer, uint8_t *pucItem)
{
//Check arguments and buffer state
configASSERT(rbCHECK_ALIGNED(pucItem));
configASSERT(pucItem >= pxRingbuffer->pucHead);
configASSERT(pucItem <= pxRingbuffer->pucTail); //Inclusive of pucTail in the case of zero length item at the very end
//Get and check header of the item
ItemHeader_t *pxCurHeader = (ItemHeader_t *)(pucItem - rbHEADER_SIZE);
configASSERT(pxCurHeader->xItemLen <= pxRingbuffer->xMaxItemSize);
configASSERT((pxCurHeader->uxItemFlags & rbITEM_DUMMY_DATA_FLAG) == 0); //Dummy items should never have been read
configASSERT((pxCurHeader->uxItemFlags & rbITEM_FREE_FLAG) == 0); //Indicates item has already been returned before
pxCurHeader->uxItemFlags &= ~rbITEM_SPLIT_FLAG; //Clear wrap flag if set (not strictly necessary)
pxCurHeader->uxItemFlags |= rbITEM_FREE_FLAG; //Mark as free
/*
* Items might not be returned in the order they were retrieved. Move the free pointer
* up to the next item that has not been marked as free (by free flag) or up
* till the read pointer. When advancing the free pointer, items that have already been
* freed or items with dummy data should be skipped over
*/
pxCurHeader = (ItemHeader_t *)pxRingbuffer->pucFree;
//Skip over Items that have already been freed or are dummy items
while (((pxCurHeader->uxItemFlags & rbITEM_FREE_FLAG) || (pxCurHeader->uxItemFlags & rbITEM_DUMMY_DATA_FLAG)) && pxRingbuffer->pucFree != pxRingbuffer->pucRead) {
if (pxCurHeader->uxItemFlags & rbITEM_DUMMY_DATA_FLAG) {
pxCurHeader->uxItemFlags |= rbITEM_FREE_FLAG; //Mark as freed (not strictly necessary but adds redundancy)
pxRingbuffer->pucFree = pxRingbuffer->pucHead; //Wrap around due to dummy data
} else {
//Item with data that has already been freed, advance free pointer past this item
size_t xAlignedItemSize = rbALIGN_SIZE(pxCurHeader->xItemLen);
pxRingbuffer->pucFree += xAlignedItemSize + rbHEADER_SIZE;
//Redundancy check to ensure free pointer has not overshot buffer bounds
configASSERT(pxRingbuffer->pucFree <= pxRingbuffer->pucHead + pxRingbuffer->xSize);
}
//Check if pucRead requires wrap around
if ((pxRingbuffer->pucTail - pxRingbuffer->pucFree) < rbHEADER_SIZE) {
pxRingbuffer->pucFree = pxRingbuffer->pucHead;
}
pxCurHeader = (ItemHeader_t *)pxRingbuffer->pucFree; //Update header to point to item
}
//Check if the buffer full flag should be reset
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
if (pxRingbuffer->pucFree != pxRingbuffer->pucWrite) {
pxRingbuffer->uxRingbufferFlags &= ~rbBUFFER_FULL_FLAG;
} else if (pxRingbuffer->pucFree == pxRingbuffer->pucWrite && pxRingbuffer->pucFree == pxRingbuffer->pucRead) {
//Special case where a full buffer is completely freed in one go
pxRingbuffer->uxRingbufferFlags &= ~rbBUFFER_FULL_FLAG;
}
}
}
static void prvReturnItemByteBuf(Ringbuffer_t *pxRingbuffer, uint8_t *pucItem)
{
//Check pointer points to address inside buffer
configASSERT((uint8_t *)pucItem >= pxRingbuffer->pucHead);
configASSERT((uint8_t *)pucItem < pxRingbuffer->pucTail);
//Free the read memory. Simply moves free pointer to read pointer as byte buffers do not allow multiple outstanding reads
pxRingbuffer->pucFree = pxRingbuffer->pucRead;
//If buffer was full before, reset full flag as free pointer has moved
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
pxRingbuffer->uxRingbufferFlags &= ~rbBUFFER_FULL_FLAG;
}
}
static size_t prvGetCurMaxSizeNoSplit(Ringbuffer_t *pxRingbuffer)
{
BaseType_t xFreeSize;
//Check if buffer is full
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
return 0;
}
if (pxRingbuffer->pucWrite < pxRingbuffer->pucFree) {
//Free space is contiguous between pucWrite and pucFree
xFreeSize = pxRingbuffer->pucFree - pxRingbuffer->pucWrite;
} else {
//Free space wraps around (or overlapped at pucHead), select largest
//contiguous free space as no-split items require contiguous space
size_t xSize1 = pxRingbuffer->pucTail - pxRingbuffer->pucWrite;
size_t xSize2 = pxRingbuffer->pucFree - pxRingbuffer->pucHead;
xFreeSize = (xSize1 > xSize2) ? xSize1 : xSize2;
}
//No-split ring buffer items need space for a header
xFreeSize -= rbHEADER_SIZE;
//Limit free size to be within bounds
if (xFreeSize > pxRingbuffer->xMaxItemSize) {
xFreeSize = pxRingbuffer->xMaxItemSize;
} else if (xFreeSize < 0) {
//Occurs when free space is less than header size
xFreeSize = 0;
}
return xFreeSize;
}
static size_t prvGetCurMaxSizeAllowSplit(Ringbuffer_t *pxRingbuffer)
{
BaseType_t xFreeSize;
//Check if buffer is full
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
return 0;
}
if (pxRingbuffer->pucWrite == pxRingbuffer->pucHead && pxRingbuffer->pucFree == pxRingbuffer->pucHead) {
//Check for special case where pucWrite and pucFree are both at pucHead
xFreeSize = pxRingbuffer->xSize - rbHEADER_SIZE;
} else if (pxRingbuffer->pucWrite < pxRingbuffer->pucFree) {
//Free space is contiguous between pucWrite and pucFree, requires single header
xFreeSize = (pxRingbuffer->pucFree - pxRingbuffer->pucWrite) - rbHEADER_SIZE;
} else {
//Free space wraps around, requires two headers
xFreeSize = (pxRingbuffer->pucFree - pxRingbuffer->pucHead) +
(pxRingbuffer->pucTail - pxRingbuffer->pucWrite) -
(rbHEADER_SIZE * 2);
}
//Limit free size to be within bounds
if (xFreeSize > pxRingbuffer->xMaxItemSize) {
xFreeSize = pxRingbuffer->xMaxItemSize;
} else if (xFreeSize < 0) {
xFreeSize = 0;
}
return xFreeSize;
}
static size_t prvGetCurMaxSizeByteBuf(Ringbuffer_t *pxRingbuffer)
{
BaseType_t xFreeSize;
//Check if buffer is full
if (pxRingbuffer->uxRingbufferFlags & rbBUFFER_FULL_FLAG) {
return 0;
}
/*
* Return whatever space is available depending on relative positions of the free
* pointer and write pointer. There is no overhead of headers in this mode
*/
xFreeSize = pxRingbuffer->pucFree - pxRingbuffer->pucWrite;
if (xFreeSize <= 0) {
xFreeSize += pxRingbuffer->xSize;
}
return xFreeSize;
}
static BaseType_t prvReceiveGeneric(Ringbuffer_t *pxRingbuffer, void **pvItem1, void **pvItem2, size_t *xItemSize1, size_t *xItemSize2, size_t xMaxSize, TickType_t xTicksToWait)
{
BaseType_t xReturn = pdFALSE;
BaseType_t xReturnSemaphore = pdFALSE;
TickType_t xTicksEnd = xTaskGetTickCount() + xTicksToWait;
TickType_t xTicksRemaining = xTicksToWait;
while (xTicksRemaining <= xTicksToWait) { //xTicksToWait will underflow once xTaskGetTickCount() > ticks_end
//Block until more free space becomes available or timeout
if (xSemaphoreTake(pxRingbuffer->xItemsBufferedSemaphore, xTicksRemaining) != pdTRUE) {
xReturn = pdFALSE; //Timed out attempting to get semaphore
break;
}
//Semaphore obtained, check if item can be retrieved
taskENTER_CRITICAL(&pxRingbuffer->mux);
if (prvCheckItemAvail(pxRingbuffer) == pdTRUE) {
//Item is available for retrieval
BaseType_t xIsSplit;
if (pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG) {
//Second argument (pxIsSplit) is unused for byte buffers
*pvItem1 = pxRingbuffer->pvGetItem(pxRingbuffer, NULL, xMaxSize, xItemSize1);
} else {
//Third argument (xMaxSize) is unused for no-split/allow-split buffers
*pvItem1 = pxRingbuffer->pvGetItem(pxRingbuffer, &xIsSplit, 0, xItemSize1);
}
//Check for item split if configured to do so
if ((pxRingbuffer->uxRingbufferFlags & rbALLOW_SPLIT_FLAG) && (pvItem2 != NULL) && (xItemSize2 != NULL)) {
if (xIsSplit == pdTRUE) {
*pvItem2 = pxRingbuffer->pvGetItem(pxRingbuffer, &xIsSplit, 0, xItemSize2);
configASSERT(*pvItem2 < *pvItem1); //Check wrap around has occurred
configASSERT(xIsSplit == pdFALSE); //Second part should not have wrapped flag
} else {
*pvItem2 = NULL;
}
}
xReturn = pdTRUE;
if (pxRingbuffer->xItemsWaiting > 0) {
xReturnSemaphore = pdTRUE;
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
break;
}
//No item available for retrieval, adjust ticks and take the semaphore again
if (xTicksToWait != portMAX_DELAY) {
xTicksRemaining = xTicksEnd - xTaskGetTickCount();
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
/*
* Gap between critical section and re-acquiring of the semaphore. If
* semaphore is given now, priority inversion might occur (see docs)
*/
}
if (xReturnSemaphore == pdTRUE) {
xSemaphoreGive(pxRingbuffer->xItemsBufferedSemaphore); //Give semaphore back so other tasks can retrieve
}
return xReturn;
}
static BaseType_t prvReceiveGenericFromISR(Ringbuffer_t *pxRingbuffer, void **pvItem1, void **pvItem2, size_t *xItemSize1, size_t *xItemSize2, size_t xMaxSize)
{
BaseType_t xReturn = pdFALSE;
BaseType_t xReturnSemaphore = pdFALSE;
taskENTER_CRITICAL_ISR(&pxRingbuffer->mux);
if(prvCheckItemAvail(pxRingbuffer) == pdTRUE) {
BaseType_t xIsSplit;
if (pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG) {
//Second argument (pxIsSplit) is unused for byte buffers
*pvItem1 = pxRingbuffer->pvGetItem(pxRingbuffer, NULL, xMaxSize, xItemSize1);
} else {
//Third argument (xMaxSize) is unused for no-split/allow-split buffers
*pvItem1 = pxRingbuffer->pvGetItem(pxRingbuffer, &xIsSplit, 0, xItemSize1);
}
//Check for item split if configured to do so
if ((pxRingbuffer->uxRingbufferFlags & rbALLOW_SPLIT_FLAG) && pvItem2 != NULL && xItemSize2 != NULL) {
if (xIsSplit == pdTRUE) {
*pvItem2 = pxRingbuffer->pvGetItem(pxRingbuffer, &xIsSplit, 0, xItemSize2);
configASSERT(*pvItem2 < *pvItem1); //Check wrap around has occurred
configASSERT(xIsSplit == pdFALSE); //Second part should not have wrapped flag
} else {
*pvItem2 = NULL;
}
}
xReturn = pdTRUE;
if (pxRingbuffer->xItemsWaiting > 0) {
xReturnSemaphore = pdTRUE;
}
}
taskEXIT_CRITICAL_ISR(&pxRingbuffer->mux);
if (xReturnSemaphore == pdTRUE) {
xSemaphoreGiveFromISR(pxRingbuffer->xItemsBufferedSemaphore, NULL); //Give semaphore back so other tasks can retrieve
}
return xReturn;
}
/* ------------------------------------------------- Public Definitions -------------------------------------------- */
RingbufHandle_t xRingbufferCreate(size_t xBufferSize, ringbuf_type_t xBufferType)
{
//Allocate memory
Ringbuffer_t *pxRingbuffer = calloc(1, sizeof(Ringbuffer_t));
if (pxRingbuffer == NULL) {
goto err;
}
if (xBufferType != RINGBUF_TYPE_BYTEBUF) {
xBufferSize = rbALIGN_SIZE(xBufferSize); //xBufferSize is rounded up for no-split/allow-split buffers
}
pxRingbuffer->pucHead = malloc(xBufferSize);
if (pxRingbuffer->pucHead == NULL) {
goto err;
}
//Initialize values
pxRingbuffer->xSize = xBufferSize;
pxRingbuffer->pucTail = pxRingbuffer->pucHead + xBufferSize;
pxRingbuffer->pucFree = pxRingbuffer->pucHead;
pxRingbuffer->pucRead = pxRingbuffer->pucHead;
pxRingbuffer->pucWrite = pxRingbuffer->pucHead;
pxRingbuffer->xItemsWaiting = 0;
pxRingbuffer->xFreeSpaceSemaphore = xSemaphoreCreateBinary();
pxRingbuffer->xItemsBufferedSemaphore = xSemaphoreCreateBinary();
pxRingbuffer->uxRingbufferFlags = 0;
//Initialize type dependent values and function pointers
if (xBufferType == RINGBUF_TYPE_NOSPLIT) {
pxRingbuffer->xCheckItemFits = prvCheckItemFitsDefault;
pxRingbuffer->vCopyItem = prvCopyItemNoSplit;
pxRingbuffer->pvGetItem = prvGetItemDefault;
pxRingbuffer->vReturnItem = prvReturnItemDefault;
/*
* Buffer lengths are always aligned. No-split buffer (read/write/free)
* pointers are also always aligned. Therefore worse case scenario is
* the write pointer is at the most aligned halfway point.
*/
pxRingbuffer->xMaxItemSize = rbALIGN_SIZE(pxRingbuffer->xSize / 2) - rbHEADER_SIZE;
pxRingbuffer->xGetCurMaxSize = prvGetCurMaxSizeNoSplit;
} else if (xBufferType == RINGBUF_TYPE_ALLOWSPLIT) {
pxRingbuffer->uxRingbufferFlags |= rbALLOW_SPLIT_FLAG;
pxRingbuffer->xCheckItemFits = prvCheckItemFitsDefault;
pxRingbuffer->vCopyItem = prvCopyItemAllowSplit;
pxRingbuffer->pvGetItem = prvGetItemDefault;
pxRingbuffer->vReturnItem = prvReturnItemDefault;
//Worst case an item is split into two, incurring two headers of overhead
pxRingbuffer->xMaxItemSize = pxRingbuffer->xSize - (sizeof(ItemHeader_t) * 2);
pxRingbuffer->xGetCurMaxSize = prvGetCurMaxSizeAllowSplit;
} else if (xBufferType == RINGBUF_TYPE_BYTEBUF) {
pxRingbuffer->uxRingbufferFlags |= rbBYTE_BUFFER_FLAG;
pxRingbuffer->xCheckItemFits = prvCheckItemFitsByteBuffer;
pxRingbuffer->vCopyItem = prvCopyItemByteBuf;
pxRingbuffer->pvGetItem = prvGetItemByteBuf;
pxRingbuffer->vReturnItem = prvReturnItemByteBuf;
//Byte buffers do not incur any overhead
pxRingbuffer->xMaxItemSize = pxRingbuffer->xSize;
pxRingbuffer->xGetCurMaxSize = prvGetCurMaxSizeByteBuf;
} else {
//Unsupported type
configASSERT(0);
}
if (pxRingbuffer->xFreeSpaceSemaphore == NULL || pxRingbuffer->xItemsBufferedSemaphore == NULL) {
goto err;
}
xSemaphoreGive(pxRingbuffer->xFreeSpaceSemaphore);
vPortCPUInitializeMutex(&pxRingbuffer->mux);
return (RingbufHandle_t)pxRingbuffer;
err:
//Some error has happened. Free/destroy all allocated things and return NULL.
if (pxRingbuffer) {
free(pxRingbuffer->pucHead);
if (pxRingbuffer->xFreeSpaceSemaphore) {
vSemaphoreDelete(pxRingbuffer->xFreeSpaceSemaphore);
}
if (pxRingbuffer->xItemsBufferedSemaphore) {
vSemaphoreDelete(pxRingbuffer->xItemsBufferedSemaphore);
}
}
free(pxRingbuffer);
return NULL;
}
RingbufHandle_t xRingbufferCreateNoSplit(size_t xItemSize, size_t xItemNum)
{
return xRingbufferCreate((rbALIGN_SIZE(xItemSize) + rbHEADER_SIZE) * xItemNum, RINGBUF_TYPE_NOSPLIT);
}
BaseType_t xRingbufferSend(RingbufHandle_t xRingbuffer, const void *pvItem, size_t xItemSize, TickType_t xTicksToWait)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pvItem != NULL || xItemSize == 0);
if (xItemSize > pxRingbuffer->xMaxItemSize) {
return pdFALSE; //Data will never ever fit in the queue.
}
if ((pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG) && xItemSize == 0) {
return pdTRUE; //Sending 0 bytes to byte buffer has no effect
}
//Attempt to send an item
BaseType_t xReturn = pdFALSE;
BaseType_t xReturnSemaphore = pdFALSE;
TickType_t xTicksEnd = xTaskGetTickCount() + xTicksToWait;
TickType_t xTicksRemaining = xTicksToWait;
while (xTicksRemaining <= xTicksToWait) { //xTicksToWait will underflow once xTaskGetTickCount() > ticks_end
//Block until more free space becomes available or timeout
if (xSemaphoreTake(pxRingbuffer->xFreeSpaceSemaphore, xTicksRemaining) != pdTRUE) {
xReturn = pdFALSE;
break;
}
//Semaphore obtained, check if item can fit
taskENTER_CRITICAL(&pxRingbuffer->mux);
if(pxRingbuffer->xCheckItemFits(pxRingbuffer, xItemSize) == pdTRUE) {
//Item will fit, copy item
pxRingbuffer->vCopyItem(pxRingbuffer, pvItem, xItemSize);
xReturn = pdTRUE;
//Check if the free semaphore should be returned to allow other tasks to send
if (prvGetFreeSize(pxRingbuffer) > 0) {
xReturnSemaphore = pdTRUE;
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
break;
}
//Item doesn't fit, adjust ticks and take the semaphore again
if (xTicksToWait != portMAX_DELAY) {
xTicksRemaining = xTicksEnd - xTaskGetTickCount();
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
/*
* Gap between critical section and re-acquiring of the semaphore. If
* semaphore is given now, priority inversion might occur (see docs)
*/
}
if (xReturn == pdTRUE) {
//Indicate item was successfully sent
xSemaphoreGive(pxRingbuffer->xItemsBufferedSemaphore);
}
if (xReturnSemaphore == pdTRUE) {
xSemaphoreGive(pxRingbuffer->xFreeSpaceSemaphore); //Give back semaphore so other tasks can send
}
return xReturn;
}
BaseType_t xRingbufferSendFromISR(RingbufHandle_t xRingbuffer, const void *pvItem, size_t xItemSize, BaseType_t *pxHigherPriorityTaskWoken)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pvItem != NULL || xItemSize == 0);
if (xItemSize > pxRingbuffer->xMaxItemSize) {
return pdFALSE; //Data will never ever fit in the queue.
}
if ((pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG) && xItemSize == 0) {
return pdTRUE; //Sending 0 bytes to byte buffer has no effect
}
//Attempt to send an item
BaseType_t xReturn;
BaseType_t xReturnSemaphore = pdFALSE;
taskENTER_CRITICAL_ISR(&pxRingbuffer->mux);
if (pxRingbuffer->xCheckItemFits(xRingbuffer, xItemSize) == pdTRUE) {
pxRingbuffer->vCopyItem(xRingbuffer, pvItem, xItemSize);
xReturn = pdTRUE;
//Check if the free semaphore should be returned to allow other tasks to send
if (prvGetFreeSize(pxRingbuffer) > 0) {
xReturnSemaphore = pdTRUE;
}
} else {
xReturn = pdFALSE;
}
taskEXIT_CRITICAL_ISR(&pxRingbuffer->mux);
if (xReturn == pdTRUE) {
//Indicate item was successfully sent
xSemaphoreGiveFromISR(pxRingbuffer->xItemsBufferedSemaphore, pxHigherPriorityTaskWoken);
}
if (xReturnSemaphore == pdTRUE) {
xSemaphoreGiveFromISR(pxRingbuffer->xFreeSpaceSemaphore, pxHigherPriorityTaskWoken); //Give back semaphore so other tasks can send
}
return xReturn;
}
void *xRingbufferReceive(RingbufHandle_t xRingbuffer, size_t *pxItemSize, TickType_t xTicksToWait)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
//Attempt to retrieve an item
void *pvTempItem;
size_t xTempSize;
if (prvReceiveGeneric(pxRingbuffer, &pvTempItem, NULL, &xTempSize, NULL, 0, xTicksToWait) == pdTRUE) {
if (pxItemSize != NULL) {
*pxItemSize = xTempSize;
}
return pvTempItem;
} else {
return NULL;
}
}
void *xRingbufferReceiveFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
//Attempt to retrieve an item
void *pvTempItem;
size_t xTempSize;
if (prvReceiveGenericFromISR(pxRingbuffer, &pvTempItem, NULL, &xTempSize, NULL, 0) == pdTRUE) {
if (pxItemSize != NULL) {
*pxItemSize = xTempSize;
}
return pvTempItem;
} else {
return NULL;
}
}
BaseType_t xRingbufferReceiveSplit(RingbufHandle_t xRingbuffer, void **ppvHeadItem, void **ppvTailItem, size_t *pxHeadItemSize, size_t *pxTailItemSize, TickType_t xTicksToWait)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pxRingbuffer->uxRingbufferFlags & rbALLOW_SPLIT_FLAG);
configASSERT(ppvHeadItem != NULL && ppvTailItem != NULL);
//Attempt to retrieve multiple items
void *pvTempHeadItem, *pvTempTailItem;
size_t xTempHeadSize, xTempTailSize;
if (prvReceiveGeneric(pxRingbuffer, &pvTempHeadItem, &pvTempTailItem, &xTempHeadSize, &xTempTailSize, 0, xTicksToWait) == pdTRUE) {
//At least one item was retrieved
*ppvHeadItem = pvTempHeadItem;
if(pxHeadItemSize != NULL){
*pxHeadItemSize = xTempHeadSize;
}
//Check to see if a second item was also retrieved
if (pvTempTailItem != NULL) {
*ppvTailItem = pvTempTailItem;
if (pxTailItemSize != NULL) {
*pxTailItemSize = xTempTailSize;
}
} else {
*ppvTailItem = NULL;
}
return pdTRUE;
} else {
//No items retrieved
*ppvHeadItem = NULL;
*ppvTailItem = NULL;
return pdFALSE;
}
}
BaseType_t xRingbufferReceiveSplitFromISR(RingbufHandle_t xRingbuffer, void **ppvHeadItem, void **ppvTailItem, size_t *pxHeadItemSize, size_t *pxTailItemSize)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pxRingbuffer->uxRingbufferFlags & rbALLOW_SPLIT_FLAG);
configASSERT(ppvHeadItem != NULL && ppvTailItem != NULL);
//Attempt to retrieve multiple items
void *pvTempHeadItem, *pvTempTailItem;
size_t xTempHeadSize, xTempTailSize;
if (prvReceiveGenericFromISR(pxRingbuffer, &pvTempHeadItem, &pvTempTailItem, &xTempHeadSize, &xTempTailSize, 0) == pdTRUE) {
//At least one item was received
*ppvHeadItem = pvTempHeadItem;
if (pxHeadItemSize != NULL) {
*pxHeadItemSize = xTempHeadSize;
}
//Check to see if a second item was also retrieved
if (pvTempTailItem != NULL) {
*ppvTailItem = pvTempTailItem;
if (pxTailItemSize != NULL) {
*pxTailItemSize = xTempTailSize;
}
} else {
*ppvTailItem = NULL;
}
return pdTRUE;
} else {
*ppvHeadItem = NULL;
*ppvTailItem = NULL;
return pdFALSE;
}
}
void *xRingbufferReceiveUpTo(RingbufHandle_t xRingbuffer, size_t *pxItemSize, TickType_t xTicksToWait, size_t xMaxSize)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG); //This function should only be called for byte buffers
if (xMaxSize == 0) {
return NULL;
}
//Attempt to retrieve up to xMaxSize bytes
void *pvTempItem;
size_t xTempSize;
if (prvReceiveGeneric(pxRingbuffer, &pvTempItem, NULL, &xTempSize, NULL, xMaxSize, xTicksToWait) == pdTRUE) {
if (pxItemSize != NULL) {
*pxItemSize = xTempSize;
}
return pvTempItem;
} else {
return NULL;
}
}
void *xRingbufferReceiveUpToFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize, size_t xMaxSize)
{
//Check arguments
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pxRingbuffer->uxRingbufferFlags & rbBYTE_BUFFER_FLAG); //This function should only be called for byte buffers
if (xMaxSize == 0) {
return NULL;
}
//Attempt to retrieve up to xMaxSize bytes
void *pvTempItem;
size_t xTempSize;
if (prvReceiveGenericFromISR(pxRingbuffer, &pvTempItem, NULL, &xTempSize, NULL, xMaxSize) == pdTRUE) {
if (pxItemSize != NULL) {
*pxItemSize = xTempSize;
}
return pvTempItem;
} else {
return NULL;
}
}
void vRingbufferReturnItem(RingbufHandle_t xRingbuffer, void *pvItem)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pvItem != NULL);
taskENTER_CRITICAL(&pxRingbuffer->mux);
pxRingbuffer->vReturnItem(pxRingbuffer, (uint8_t *)pvItem);
taskEXIT_CRITICAL(&pxRingbuffer->mux);
xSemaphoreGive(pxRingbuffer->xFreeSpaceSemaphore);
}
void vRingbufferReturnItemFromISR(RingbufHandle_t xRingbuffer, void *pvItem, BaseType_t *pxHigherPriorityTaskWoken)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
configASSERT(pvItem != NULL);
taskENTER_CRITICAL_ISR(&pxRingbuffer->mux);
pxRingbuffer->vReturnItem(pxRingbuffer, (uint8_t *)pvItem);
taskEXIT_CRITICAL_ISR(&pxRingbuffer->mux);
xSemaphoreGiveFromISR(pxRingbuffer->xFreeSpaceSemaphore, pxHigherPriorityTaskWoken);
}
void vRingbufferDelete(RingbufHandle_t xRingbuffer)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
if (pxRingbuffer) {
free(pxRingbuffer->pucHead);
if (pxRingbuffer->xFreeSpaceSemaphore) {
vSemaphoreDelete(pxRingbuffer->xFreeSpaceSemaphore);
}
if (pxRingbuffer->xItemsBufferedSemaphore) {
vSemaphoreDelete(pxRingbuffer->xItemsBufferedSemaphore);
}
}
free(pxRingbuffer);
}
size_t xRingbufferGetMaxItemSize(RingbufHandle_t xRingbuffer)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
return pxRingbuffer->xMaxItemSize;
}
size_t xRingbufferGetCurFreeSize(RingbufHandle_t xRingbuffer)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
size_t xFreeSize;
taskENTER_CRITICAL(&pxRingbuffer->mux);
xFreeSize = pxRingbuffer->xGetCurMaxSize(pxRingbuffer);
taskEXIT_CRITICAL(&pxRingbuffer->mux);
return xFreeSize;
}
BaseType_t xRingbufferAddToQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
BaseType_t xReturn;
taskENTER_CRITICAL(&pxRingbuffer->mux);
//Cannot add semaphore to queue set if semaphore is not empty. Temporarily hold semaphore
BaseType_t xHoldSemaphore = xSemaphoreTake(pxRingbuffer->xItemsBufferedSemaphore, 0);
xReturn = xQueueAddToSet(pxRingbuffer->xItemsBufferedSemaphore, xQueueSet);
if (xHoldSemaphore == pdTRUE) {
//Return semaphore if temporarily held
configASSERT(xSemaphoreGive(pxRingbuffer->xItemsBufferedSemaphore) == pdTRUE);
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
return xReturn;
}
BaseType_t xRingbufferCanRead(RingbufHandle_t xRingbuffer, QueueSetMemberHandle_t xMember)
{
//Check if the selected queue set member is the ring buffer's read semaphore
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
return (pxRingbuffer->xItemsBufferedSemaphore == xMember) ? pdTRUE : pdFALSE;
}
BaseType_t xRingbufferRemoveFromQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
BaseType_t xReturn;
taskENTER_CRITICAL(&pxRingbuffer->mux);
//Cannot remove semaphore from queue set if semaphore is not empty. Temporarily hold semaphore
BaseType_t xHoldSemaphore = xSemaphoreTake(pxRingbuffer->xItemsBufferedSemaphore, 0);
xReturn = xQueueRemoveFromSet(pxRingbuffer->xItemsBufferedSemaphore, xQueueSet);
if (xHoldSemaphore == pdTRUE) {
//Return semaphore if temporarily held
configASSERT(xSemaphoreGive(pxRingbuffer->xItemsBufferedSemaphore) == pdTRUE);
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
return xReturn;
}
void vRingbufferGetInfo(RingbufHandle_t xRingbuffer, UBaseType_t *uxFree, UBaseType_t *uxRead, UBaseType_t *uxWrite, UBaseType_t *uxItemsWaiting)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
taskENTER_CRITICAL(&pxRingbuffer->mux);
if (uxFree != NULL) {
*uxFree = (UBaseType_t)(pxRingbuffer->pucFree - pxRingbuffer->pucHead);
}
if (uxRead != NULL) {
*uxRead = (UBaseType_t)(pxRingbuffer->pucRead - pxRingbuffer->pucHead);
}
if (uxWrite != NULL) {
*uxWrite = (UBaseType_t)(pxRingbuffer->pucWrite - pxRingbuffer->pucHead);
}
if (uxItemsWaiting != NULL) {
*uxItemsWaiting = (UBaseType_t)(pxRingbuffer->xItemsWaiting);
}
taskEXIT_CRITICAL(&pxRingbuffer->mux);
}
void xRingbufferPrintInfo(RingbufHandle_t xRingbuffer)
{
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
printf("Rb size:%d\tfree: %d\trptr: %d\tfreeptr: %d\twptr: %d\n",
pxRingbuffer->xSize, prvGetFreeSize(pxRingbuffer),
pxRingbuffer->pucRead - pxRingbuffer->pucHead,
pxRingbuffer->pucFree - pxRingbuffer->pucHead,
pxRingbuffer->pucWrite - pxRingbuffer->pucHead);
}
/* --------------------------------- Deprecated Functions ------------------------------ */
//Todo: Remove the following deprecated functions in next release
bool xRingbufferIsNextItemWrapped(RingbufHandle_t xRingbuffer)
{
//This function is deprecated, use xRingbufferReceiveSplit() instead
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
bool is_wrapped;
portENTER_CRITICAL(&pxRingbuffer->mux);
ItemHeader_t *xHeader = (ItemHeader_t *)pxRingbuffer->pucRead;
is_wrapped = xHeader->uxItemFlags & rbITEM_SPLIT_FLAG;
portEXIT_CRITICAL(&pxRingbuffer->mux);
return is_wrapped;
}
BaseType_t xRingbufferAddToQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet)
{
//This function is deprecated. QueueSetWrite no longer supported
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
BaseType_t xReturn;
portENTER_CRITICAL(&pxRingbuffer->mux);
//Cannot add semaphore to queue set if semaphore is not empty. Temporary hold semaphore
BaseType_t xHoldSemaphore = xSemaphoreTake(pxRingbuffer->xFreeSpaceSemaphore, 0);
xReturn = xQueueAddToSet(pxRingbuffer->xFreeSpaceSemaphore, xQueueSet);
if (xHoldSemaphore == pdTRUE) {
//Return semaphore is temporarily held
configASSERT(xSemaphoreGive(pxRingbuffer->xFreeSpaceSemaphore) == pdTRUE);
}
portEXIT_CRITICAL(&pxRingbuffer->mux);
return xReturn;
}
BaseType_t xRingbufferRemoveFromQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet)
{
//This function is deprecated. QueueSetWrite no longer supported
Ringbuffer_t *pxRingbuffer = (Ringbuffer_t *)xRingbuffer;
configASSERT(pxRingbuffer);
BaseType_t xReturn;
portENTER_CRITICAL(&pxRingbuffer->mux);
//Cannot remove semaphore from queue set if semaphore is not empty. Temporary hold semaphore
BaseType_t xHoldSemaphore = xSemaphoreTake(pxRingbuffer->xFreeSpaceSemaphore, 0);
xReturn = xQueueRemoveFromSet(pxRingbuffer->xFreeSpaceSemaphore, xQueueSet);
if (xHoldSemaphore == pdTRUE) {
//Return semaphore is temporarily held
configASSERT(xSemaphoreGive(pxRingbuffer->xFreeSpaceSemaphore) == pdTRUE);
}
portEXIT_CRITICAL(&pxRingbuffer->mux);
return xReturn;
}
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