// Copyright 2015-2019 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.
#ifndef FREERTOS_RINGBUF_H
#define FREERTOS_RINGBUF_H
#ifndef INC_FREERTOS_H
#error "include FreeRTOS.h" must appear in source files before "include ringbuf.h"
#endif
#ifdef __cplusplus
extern "C" {
#endif
#include <freertos/queue.h>
/**
* Type by which ring buffers are referenced. For example, a call to xRingbufferCreate()
* returns a RingbufHandle_t variable that can then be used as a parameter to
* xRingbufferSend(), xRingbufferReceive(), etc.
*/
typedef void * RingbufHandle_t;
typedef enum {
/**
* No-split buffers will only store an item in contiguous memory and will
* never split an item. Each item requires an 8 byte overhead for a header
* and will always internally occupy a 32-bit aligned size of space.
*/
RINGBUF_TYPE_NOSPLIT = 0,
/**
* Allow-split buffers will split an item into two parts if necessary in
* order to store it. Each item requires an 8 byte overhead for a header,
* splitting incurs an extra header. Each item will always internally occupy
* a 32-bit aligned size of space.
*/
RINGBUF_TYPE_ALLOWSPLIT,
/**
* Byte buffers store data as a sequence of bytes and do not maintain separate
* items, therefore byte buffers have no overhead. All data is stored as a
* sequence of byte and any number of bytes can be sent or retrieved each
* time.
*/
RINGBUF_TYPE_BYTEBUF,
RINGBUF_TYPE_MAX,
} RingbufferType_t;
/**
* @brief Struct that is equivalent in size to the ring buffer's data structure
*
* The contents of this struct are not meant to be used directly. This
* structure is meant to be used when creating a statically allocated ring
* buffer where this struct is of the exact size required to store a ring
* buffer's control data structure.
*
* @note The CONFIG_FREERTOS_SUPPORT_STATIC_ALLOCATION option must be enabled for
* this structure to be available.
*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1)
typedef struct xSTATIC_RINGBUFFER {
/** @cond */ //Doxygen command to hide this structure from API Reference
size_t xDummy1[2];
UBaseType_t uxDummy2;
BaseType_t xDummy3;
void *pvDummy4[11];
StaticSemaphore_t xDummy5[2];
portMUX_TYPE muxDummy;
/** @endcond */
} StaticRingbuffer_t;
#endif
/**
* @brief Create a ring buffer
*
* @param[in] xBufferSize Size of the buffer in bytes. Note that items require
* space for overhead in no-split/allow-split buffers
* @param[in] xBufferType Type of ring buffer, see documentation.
*
* @note xBufferSize of no-split/allow-split buffers will be rounded up to the nearest 32-bit aligned size.
*
* @return A handle to the created ring buffer, or NULL in case of error.
*/
RingbufHandle_t xRingbufferCreate(size_t xBufferSize, RingbufferType_t xBufferType);
/**
* @brief Create a ring buffer of type RINGBUF_TYPE_NOSPLIT for a fixed item_size
*
* This API is similar to xRingbufferCreate(), but it will internally allocate
* additional space for the headers.
*
* @param[in] xItemSize Size of each item to be put into the ring buffer
* @param[in] xItemNum Maximum number of items the buffer needs to hold simultaneously
*
* @return A RingbufHandle_t handle to the created ring buffer, or NULL in case of error.
*/
RingbufHandle_t xRingbufferCreateNoSplit(size_t xItemSize, size_t xItemNum);
/**
* @brief Create a ring buffer but manually provide the required memory
*
* @param[in] xBufferSize Size of the buffer in bytes.
* @param[in] xBufferType Type of ring buffer, see documentation
* @param[in] pucRingbufferStorage Pointer to the ring buffer's storage area.
* Storage area must of the same size as specified by xBufferSize
* @param[in] pxStaticRingbuffer Pointed to a struct of type StaticRingbuffer_t
* which will be used to hold the ring buffer's data structure
*
* @note The CONFIG_FREERTOS_SUPPORT_STATIC_ALLOCATION option must be enabled
* for this to be available
*
* @note xBufferSize of no-split/allow-split buffers MUST be 32-bit aligned.
*
* @return A handle to the created ring buffer
*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1)
RingbufHandle_t xRingbufferCreateStatic(size_t xBufferSize,
RingbufferType_t xBufferType,
uint8_t *pucRingbufferStorage,
StaticRingbuffer_t *pxStaticRingbuffer);
#endif
/**
* @brief Insert an item into the ring buffer
*
* Attempt to insert an item into the ring buffer. This function will block until
* enough free space is available or until it times out.
*
* @param[in] xRingbuffer Ring buffer to insert the item into
* @param[in] pvItem Pointer to data to insert. NULL is allowed if xItemSize is 0.
* @param[in] xItemSize Size of data to insert.
* @param[in] xTicksToWait Ticks to wait for room in the ring buffer.
*
* @note For no-split/allow-split ring buffers, the actual size of memory that
* the item will occupy will be rounded up to the nearest 32-bit aligned
* size. This is done to ensure all items are always stored in 32-bit
* aligned fashion.
*
* @return
* - pdTRUE if succeeded
* - pdFALSE on time-out or when the data is larger than the maximum permissible size of the buffer
*/
BaseType_t xRingbufferSend(RingbufHandle_t xRingbuffer,
const void *pvItem,
size_t xItemSize,
TickType_t xTicksToWait);
/**
* @brief Insert an item into the ring buffer in an ISR
*
* Attempt to insert an item into the ring buffer from an ISR. This function
* will return immediately if there is insufficient free space in the buffer.
*
* @param[in] xRingbuffer Ring buffer to insert the item into
* @param[in] pvItem Pointer to data to insert. NULL is allowed if xItemSize is 0.
* @param[in] xItemSize Size of data to insert.
* @param[out] pxHigherPriorityTaskWoken Value pointed to will be set to pdTRUE if the function woke up a higher priority task.
*
* @note For no-split/allow-split ring buffers, the actual size of memory that
* the item will occupy will be rounded up to the nearest 32-bit aligned
* size. This is done to ensure all items are always stored in 32-bit
* aligned fashion.
*
* @return
* - pdTRUE if succeeded
* - pdFALSE when the ring buffer does not have space.
*/
BaseType_t xRingbufferSendFromISR(RingbufHandle_t xRingbuffer,
const void *pvItem,
size_t xItemSize,
BaseType_t *pxHigherPriorityTaskWoken);
/**
* @brief Acquire memory from the ring buffer to be written to by an external
* source and to be sent later.
*
* Attempt to allocate buffer for an item to be sent into the ring buffer. This
* function will block until enough free space is available or until it
* timesout.
*
* The item, as well as the following items ``SendAcquire`` or ``Send`` after it,
* will not be able to be read from the ring buffer until this item is actually
* sent into the ring buffer.
*
* @param[in] xRingbuffer Ring buffer to allocate the memory
* @param[out] ppvItem Double pointer to memory acquired (set to NULL if no memory were retrieved)
* @param[in] xItemSize Size of item to acquire.
* @param[in] xTicksToWait Ticks to wait for room in the ring buffer.
*
* @note Only applicable for no-split ring buffers now, the actual size of
* memory that the item will occupy will be rounded up to the nearest 32-bit
* aligned size. This is done to ensure all items are always stored in 32-bit
* aligned fashion.
*
* @return
* - pdTRUE if succeeded
* - pdFALSE on time-out or when the data is larger than the maximum permissible size of the buffer
*/
BaseType_t xRingbufferSendAcquire(RingbufHandle_t xRingbuffer, void **ppvItem, size_t xItemSize, TickType_t xTicksToWait);
/**
* @brief Actually send an item into the ring buffer allocated before by
* ``xRingbufferSendAcquire``.
*
* @param[in] xRingbuffer Ring buffer to insert the item into
* @param[in] pvItem Pointer to item in allocated memory to insert.
*
* @note Only applicable for no-split ring buffers. Only call for items
* allocated by ``xRingbufferSendAcquire``.
*
* @return
* - pdTRUE if succeeded
* - pdFALSE if fail for some reason.
*/
BaseType_t xRingbufferSendComplete(RingbufHandle_t xRingbuffer, void *pvItem);
/**
* @brief Retrieve an item from the ring buffer
*
* Attempt to retrieve an item from the ring buffer. This function will block
* until an item is available or until it times out.
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
*
* @note A call to vRingbufferReturnItem() is required after this to free the item retrieved.
*
* @return
* - Pointer to the retrieved item on success; *pxItemSize filled with the length of the item.
* - NULL on timeout, *pxItemSize is untouched in that case.
*/
void *xRingbufferReceive(RingbufHandle_t xRingbuffer, size_t *pxItemSize, TickType_t xTicksToWait);
/**
* @brief Retrieve an item from the ring buffer in an ISR
*
* Attempt to retrieve an item from the ring buffer. This function returns immediately
* if there are no items available for retrieval
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] pxItemSize Pointer to a variable to which the size of the
* retrieved item will be written.
*
* @note A call to vRingbufferReturnItemFromISR() is required after this to free the item retrieved.
* @note Byte buffers do not allow multiple retrievals before returning an item
*
* @return
* - Pointer to the retrieved item on success; *pxItemSize filled with the length of the item.
* - NULL when the ring buffer is empty, *pxItemSize is untouched in that case.
*/
void *xRingbufferReceiveFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize);
/**
* @brief Retrieve a split item from an allow-split ring buffer
*
* Attempt to retrieve a split item from an allow-split ring buffer. If the item
* is not split, only a single item is retried. If the item is split, both parts
* will be retrieved. This function will block until an item is available or
* until it times out.
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] ppvHeadItem Double pointer to first part (set to NULL if no items were retrieved)
* @param[out] ppvTailItem Double pointer to second part (set to NULL if item is not split)
* @param[out] pxHeadItemSize Pointer to size of first part (unmodified if no items were retrieved)
* @param[out] pxTailItemSize Pointer to size of second part (unmodified if item is not split)
* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
*
* @note Call(s) to vRingbufferReturnItem() is required after this to free up the item(s) retrieved.
* @note This function should only be called on allow-split buffers
*
* @return
* - pdTRUE if an item (split or unsplit) was retrieved
* - pdFALSE when no item was retrieved
*/
BaseType_t xRingbufferReceiveSplit(RingbufHandle_t xRingbuffer,
void **ppvHeadItem,
void **ppvTailItem,
size_t *pxHeadItemSize,
size_t *pxTailItemSize,
TickType_t xTicksToWait);
/**
* @brief Retrieve a split item from an allow-split ring buffer in an ISR
*
* Attempt to retrieve a split item from an allow-split ring buffer. If the item
* is not split, only a single item is retried. If the item is split, both parts
* will be retrieved. This function returns immediately if there are no items
* available for retrieval
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] ppvHeadItem Double pointer to first part (set to NULL if no items were retrieved)
* @param[out] ppvTailItem Double pointer to second part (set to NULL if item is not split)
* @param[out] pxHeadItemSize Pointer to size of first part (unmodified if no items were retrieved)
* @param[out] pxTailItemSize Pointer to size of second part (unmodified if item is not split)
*
* @note Calls to vRingbufferReturnItemFromISR() is required after this to free up the item(s) retrieved.
* @note This function should only be called on allow-split buffers
*
* @return
* - pdTRUE if an item (split or unsplit) was retrieved
* - pdFALSE when no item was retrieved
*/
BaseType_t xRingbufferReceiveSplitFromISR(RingbufHandle_t xRingbuffer,
void **ppvHeadItem,
void **ppvTailItem,
size_t *pxHeadItemSize,
size_t *pxTailItemSize);
/**
* @brief Retrieve bytes from a byte buffer, specifying the maximum amount of bytes to retrieve
*
* Attempt to retrieve data from a byte buffer whilst specifying a maximum number
* of bytes to retrieve. This function will block until there is data available
* for retrieval or until it times out.
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
* @param[in] xMaxSize Maximum number of bytes to return.
*
* @note A call to vRingbufferReturnItem() is required after this to free up the data retrieved.
* @note This function should only be called on byte buffers
* @note Byte buffers do not allow multiple retrievals before returning an item
*
* @return
* - Pointer to the retrieved item on success; *pxItemSize filled with
* the length of the item.
* - NULL on timeout, *pxItemSize is untouched in that case.
*/
void *xRingbufferReceiveUpTo(RingbufHandle_t xRingbuffer,
size_t *pxItemSize,
TickType_t xTicksToWait,
size_t xMaxSize);
/**
* @brief Retrieve bytes from a byte buffer, specifying the maximum amount of
* bytes to retrieve. Call this from an ISR.
*
* Attempt to retrieve bytes from a byte buffer whilst specifying a maximum number
* of bytes to retrieve. This function will return immediately if there is no data
* available for retrieval.
*
* @param[in] xRingbuffer Ring buffer to retrieve the item from
* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
* @param[in] xMaxSize Maximum number of bytes to return.
*
* @note A call to vRingbufferReturnItemFromISR() is required after this to free up the data received.
* @note This function should only be called on byte buffers
* @note Byte buffers do not allow multiple retrievals before returning an item
*
* @return
* - Pointer to the retrieved item on success; *pxItemSize filled with
* the length of the item.
* - NULL when the ring buffer is empty, *pxItemSize is untouched in that case.
*/
void *xRingbufferReceiveUpToFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize, size_t xMaxSize);
/**
* @brief Return a previously-retrieved item to the ring buffer
*
* @param[in] xRingbuffer Ring buffer the item was retrieved from
* @param[in] pvItem Item that was received earlier
*
* @note If a split item is retrieved, both parts should be returned by calling this function twice
*/
void vRingbufferReturnItem(RingbufHandle_t xRingbuffer, void *pvItem);
/**
* @brief Return a previously-retrieved item to the ring buffer from an ISR
*
* @param[in] xRingbuffer Ring buffer the item was retrieved from
* @param[in] pvItem Item that was received earlier
* @param[out] pxHigherPriorityTaskWoken Value pointed to will be set to pdTRUE
* if the function woke up a higher priority task.
*
* @note If a split item is retrieved, both parts should be returned by calling this function twice
*/
void vRingbufferReturnItemFromISR(RingbufHandle_t xRingbuffer, void *pvItem, BaseType_t *pxHigherPriorityTaskWoken);
/**
* @brief Delete a ring buffer
*
* @param[in] xRingbuffer Ring buffer to delete
*
* @note This function will not deallocate any memory if the ring buffer was
* created using xRingbufferCreateStatic(). Deallocation must be done
* manually be the user.
*/
void vRingbufferDelete(RingbufHandle_t xRingbuffer);
/**
* @brief Get maximum size of an item that can be placed in the ring buffer
*
* This function returns the maximum size an item can have if it was placed in
* an empty ring buffer.
*
* @param[in] xRingbuffer Ring buffer to query
*
* @note The max item size for a no-split buffer is limited to
* ((buffer_size/2)-header_size). This limit is imposed so that an item
* of max item size can always be sent to the an empty no-split buffer
* regardless of the internal positions of the buffer's read/write/free
* pointers.
*
* @return Maximum size, in bytes, of an item that can be placed in a ring buffer.
*/
size_t xRingbufferGetMaxItemSize(RingbufHandle_t xRingbuffer);
/**
* @brief Get current free size available for an item/data in the buffer
*
* This gives the real time free space available for an item/data in the ring
* buffer. This represents the maximum size an item/data can have if it was
* currently sent to the ring buffer.
*
* @warning This API is not thread safe. So, if multiple threads are accessing
* the same ring buffer, it is the application's responsibility to
* ensure atomic access to this API and the subsequent Send
*
* @note An empty no-split buffer has a max current free size for an item
* that is limited to ((buffer_size/2)-header_size). See API reference
* for xRingbufferGetMaxItemSize().
*
* @param[in] xRingbuffer Ring buffer to query
*
* @return Current free size, in bytes, available for an entry
*/
size_t xRingbufferGetCurFreeSize(RingbufHandle_t xRingbuffer);
/**
* @brief Add the ring buffer's read semaphore to a queue set.
*
* The ring buffer's read semaphore indicates that data has been written
* to the ring buffer. This function adds the ring buffer's read semaphore to
* a queue set.
*
* @param[in] xRingbuffer Ring buffer to add to the queue set
* @param[in] xQueueSet Queue set to add the ring buffer's read semaphore to
*
* @return
* - pdTRUE on success, pdFALSE otherwise
*/
BaseType_t xRingbufferAddToQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet);
/**
* @brief Check if the selected queue set member is the ring buffer's read semaphore
*
* This API checks if queue set member returned from xQueueSelectFromSet()
* is the read semaphore of this ring buffer. If so, this indicates the ring buffer
* has items waiting to be retrieved.
*
* @param[in] xRingbuffer Ring buffer which should be checked
* @param[in] xMember Member returned from xQueueSelectFromSet
*
* @return
* - pdTRUE when semaphore belongs to ring buffer
* - pdFALSE otherwise.
*/
BaseType_t xRingbufferCanRead(RingbufHandle_t xRingbuffer, QueueSetMemberHandle_t xMember);
/**
* @brief Remove the ring buffer's read semaphore from a queue set.
*
* This specifically removes a ring buffer's read semaphore from a queue set. The
* read semaphore is used to indicate when data has been written to the ring buffer
*
* @param[in] xRingbuffer Ring buffer to remove from the queue set
* @param[in] xQueueSet Queue set to remove the ring buffer's read semaphore from
*
* @return
* - pdTRUE on success
* - pdFALSE otherwise
*/
BaseType_t xRingbufferRemoveFromQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet);
/**
* @brief Get information about ring buffer status
*
* Get information of the a ring buffer's current status such as
* free/read/write pointer positions, and number of items waiting to be retrieved.
* Arguments can be set to NULL if they are not required.
*
* @param[in] xRingbuffer Ring buffer to remove from the queue set
* @param[out] uxFree Pointer use to store free pointer position
* @param[out] uxRead Pointer use to store read pointer position
* @param[out] uxWrite Pointer use to store write pointer position
* @param[out] uxAcquire Pointer use to store acquire pointer position
* @param[out] uxItemsWaiting Pointer use to store number of items (bytes for byte buffer) waiting to be retrieved
*/
void vRingbufferGetInfo(RingbufHandle_t xRingbuffer,
UBaseType_t *uxFree,
UBaseType_t *uxRead,
UBaseType_t *uxWrite,
UBaseType_t *uxAcquire,
UBaseType_t *uxItemsWaiting);
/**
* @brief Debugging function to print the internal pointers in the ring buffer
*
* @param xRingbuffer Ring buffer to show
*/
void xRingbufferPrintInfo(RingbufHandle_t xRingbuffer);
#ifdef __cplusplus
}
#endif
#endif /* FREERTOS_RINGBUF_H */