// 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.
#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_t;
/**
* @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, ringbuf_type_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 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 timesout.
*
* @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 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 timesout.
*
* @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 timesout.
*
* @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 timesout.
*
* @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
*/
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
*
* @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
*
* @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] 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 *uxItemsWaiting);
/**
* @brief Debugging function to print the internal pointers in the ring buffer
*
* @param xRingbuffer Ring buffer to show
*/
void xRingbufferPrintInfo(RingbufHandle_t xRingbuffer);
/* -------------------------------- Deprecated Functions --------------------------- */
/** @cond */ //Doxygen command to hide deprecated function from API Reference
/*
* Deprecated as function is not thread safe and does not check if an item is
* actually available for retrieval. Use xRingbufferReceiveSplit() instead for
* thread safe method of retrieve a split item.
*/
bool xRingbufferIsNextItemWrapped(RingbufHandle_t xRingbuffer) __attribute__((deprecated));
/*
* Deprecated as queue sets are not meant to be used for writing to buffers. Adding
* the ring buffer write semaphore to a queue set will break queue set usage rules,
* as every read of a semaphore must be preceded by a call to xQueueSelectFromSet().
* QueueSetWrite no longer supported.
*/
BaseType_t xRingbufferAddToQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet) __attribute__((deprecated));
/*
* Deprecated as queue sets are not meant to be used for writing to buffers.
* QueueSetWrite no longer supported.
*/
BaseType_t xRingbufferRemoveFromQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet) __attribute__((deprecated));
/** @endcond */
#ifdef __cplusplus
}
#endif
#endif /* FREERTOS_RINGBUF_H */