416 lines
18 KiB
C
416 lines
18 KiB
C
// Copyright 2015-2018 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef FREERTOS_RINGBUF_H
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#define FREERTOS_RINGBUF_H
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#ifndef INC_FREERTOS_H
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#error "include FreeRTOS.h" must appear in source files before "include ringbuf.h"
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <freertos/queue.h>
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/**
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* Type by which ring buffers are referenced. For example, a call to xRingbufferCreate()
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* returns a RingbufHandle_t variable that can then be used as a parameter to
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* xRingbufferSend(), xRingbufferReceive(), etc.
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*/
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typedef void * RingbufHandle_t;
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typedef enum {
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/**
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* No-split buffers will only store an item in contiguous memory and will
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* never split an item. Each item requires an 8 byte overhead for a header
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* and will always internally occupy a 32-bit aligned size of space.
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*/
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RINGBUF_TYPE_NOSPLIT = 0,
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/**
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* Allow-split buffers will split an item into two parts if necessary in
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* order to store it. Each item requires an 8 byte overhead for a header,
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* splitting incurs an extra header. Each item will always internally occupy
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* a 32-bit aligned size of space.
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*/
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RINGBUF_TYPE_ALLOWSPLIT,
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/**
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* Byte buffers store data as a sequence of bytes and do not maintain separate
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* items, therefore byte buffers have no overhead. All data is stored as a
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* sequence of byte and any number of bytes can be sent or retrieved each
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* time.
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*/
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RINGBUF_TYPE_BYTEBUF
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} ringbuf_type_t;
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/**
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* @brief Create a ring buffer
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*
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* @param[in] xBufferSize Size of the buffer in bytes. Note that items require
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* space for overhead in no-split/allow-split buffers
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* @param[in] xBufferType Type of ring buffer, see documentation.
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*
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* @note xBufferSize of no-split/allow-split buffers will be rounded up to the nearest 32-bit aligned size.
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*
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* @return A handle to the created ring buffer, or NULL in case of error.
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*/
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RingbufHandle_t xRingbufferCreate(size_t xBufferSize, ringbuf_type_t xBufferType);
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/**
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* @brief Create a ring buffer of type RINGBUF_TYPE_NOSPLIT for a fixed item_size
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*
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* This API is similar to xRingbufferCreate(), but it will internally allocate
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* additional space for the headers.
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*
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* @param[in] xItemSize Size of each item to be put into the ring buffer
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* @param[in] xItemNum Maximum number of items the buffer needs to hold simultaneously
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*
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* @return A RingbufHandle_t handle to the created ring buffer, or NULL in case of error.
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*/
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RingbufHandle_t xRingbufferCreateNoSplit(size_t xItemSize, size_t xItemNum);
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/**
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* @brief Insert an item into the ring buffer
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*
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* Attempt to insert an item into the ring buffer. This function will block until
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* enough free space is available or until it timesout.
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*
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* @param[in] xRingbuffer Ring buffer to insert the item into
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* @param[in] pvItem Pointer to data to insert. NULL is allowed if xItemSize is 0.
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* @param[in] xItemSize Size of data to insert.
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* @param[in] xTicksToWait Ticks to wait for room in the ring buffer.
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*
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* @note For no-split/allow-split ring buffers, the actual size of memory that
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* the item will occupy will be rounded up to the nearest 32-bit aligned
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* size. This is done to ensure all items are always stored in 32-bit
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* aligned fashion.
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*
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* @return
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* - pdTRUE if succeeded
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* - pdFALSE on time-out or when the data is larger than the maximum permissible size of the buffer
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*/
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BaseType_t xRingbufferSend(RingbufHandle_t xRingbuffer, const void *pvItem, size_t xItemSize, TickType_t xTicksToWait);
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/**
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* @brief Insert an item into the ring buffer in an ISR
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*
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* Attempt to insert an item into the ring buffer from an ISR. This function
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* will return immediately if there is insufficient free space in the buffer.
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*
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* @param[in] xRingbuffer Ring buffer to insert the item into
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* @param[in] pvItem Pointer to data to insert. NULL is allowed if xItemSize is 0.
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* @param[in] xItemSize Size of data to insert.
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* @param[out] pxHigherPriorityTaskWoken Value pointed to will be set to pdTRUE if the function woke up a higher priority task.
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*
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* @note For no-split/allow-split ring buffers, the actual size of memory that
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* the item will occupy will be rounded up to the nearest 32-bit aligned
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* size. This is done to ensure all items are always stored in 32-bit
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* aligned fashion.
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*
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* @return
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* - pdTRUE if succeeded
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* - pdFALSE when the ring buffer does not have space.
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*/
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BaseType_t xRingbufferSendFromISR(RingbufHandle_t xRingbuffer, const void *pvItem, size_t xItemSize, BaseType_t *pxHigherPriorityTaskWoken);
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/**
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* @brief Retrieve an item from the ring buffer
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*
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* Attempt to retrieve an item from the ring buffer. This function will block
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* until an item is available or until it timesout.
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
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* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
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*
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* @note A call to vRingbufferReturnItem() is required after this to free the item retrieved.
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*
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* @return
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* - Pointer to the retrieved item on success; *pxItemSize filled with the length of the item.
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* - NULL on timeout, *pxItemSize is untouched in that case.
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*/
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void *xRingbufferReceive(RingbufHandle_t xRingbuffer, size_t *pxItemSize, TickType_t xTicksToWait);
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/**
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* @brief Retrieve an item from the ring buffer in an ISR
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*
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* Attempt to retrieve an item from the ring buffer. This function returns immediately
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* if there are no items available for retrieval
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] pxItemSize Pointer to a variable to which the size of the
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* retrieved item will be written.
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*
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* @note A call to vRingbufferReturnItemFromISR() is required after this to free the item retrieved.
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* @note Byte buffers do not allow multiple retrievals before returning an item
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*
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* @return
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* - Pointer to the retrieved item on success; *pxItemSize filled with the length of the item.
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* - NULL when the ring buffer is empty, *pxItemSize is untouched in that case.
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*/
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void *xRingbufferReceiveFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize);
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/**
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* @brief Retrieve a split item from an allow-split ring buffer
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*
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* Attempt to retrieve a split item from an allow-split ring buffer. If the item
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* is not split, only a single item is retried. If the item is split, both parts
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* will be retrieved. This function will block until an item is available or
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* until it timesout.
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] ppvHeadItem Double pointer to first part (set to NULL if no items were retrieved)
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* @param[out] ppvTailItem Double pointer to second part (set to NULL if item is not split)
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* @param[out] pxHeadItemSize Pointer to size of first part (unmodified if no items were retrieved)
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* @param[out] pxTailItemSize Pointer to size of second part (unmodified if item is not split)
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* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
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*
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* @note Call(s) to vRingbufferReturnItem() is required after this to free up the item(s) retrieved.
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* @note This function should only be called on allow-split buffers
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*
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* @return
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* - pdTRUE if an item (split or unsplit) was retrieved
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* - pdFALSE when no item was retrieved
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*/
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BaseType_t xRingbufferReceiveSplit(RingbufHandle_t xRingbuffer, void **ppvHeadItem, void **ppvTailItem, size_t *pxHeadItemSize, size_t *pxTailItemSize, TickType_t xTicksToWait);
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/**
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* @brief Retrieve a split item from an allow-split ring buffer in an ISR
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*
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* Attempt to retrieve a split item from an allow-split ring buffer. If the item
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* is not split, only a single item is retried. If the item is split, both parts
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* will be retrieved. This function returns immediately if there are no items
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* available for retrieval
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] ppvHeadItem Double pointer to first part (set to NULL if no items were retrieved)
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* @param[out] ppvTailItem Double pointer to second part (set to NULL if item is not split)
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* @param[out] pxHeadItemSize Pointer to size of first part (unmodified if no items were retrieved)
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* @param[out] pxTailItemSize Pointer to size of second part (unmodified if item is not split)
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*
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* @note Calls to vRingbufferReturnItemFromISR() is required after this to free up the item(s) retrieved.
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* @note This function should only be called on allow-split buffers
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*
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* @return
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* - pdTRUE if an item (split or unsplit) was retrieved
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* - pdFALSE when no item was retrieved
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*/
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BaseType_t xRingbufferReceiveSplitFromISR(RingbufHandle_t xRingbuffer, void **ppvHeadItem, void **ppvTailItem, size_t *pxHeadItemSize, size_t *pxTailItemSize);
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/**
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* @brief Retrieve bytes from a byte buffer, specifying the maximum amount of bytes to retrieve
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*
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* Attempt to retrieve data from a byte buffer whilst specifying a maximum number
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* of bytes to retrieve. This function will block until there is data available
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* for retrieval or until it timesout.
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
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* @param[in] xTicksToWait Ticks to wait for items in the ring buffer.
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* @param[in] xMaxSize Maximum number of bytes to return.
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*
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* @note A call to vRingbufferReturnItem() is required after this to free up the data retrieved.
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* @note This function should only be called on byte buffers
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* @note Byte buffers do not allow multiple retrievals before returning an item
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*
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* @return
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* - Pointer to the retrieved item on success; *pxItemSize filled with
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* the length of the item.
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* - NULL on timeout, *pxItemSize is untouched in that case.
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*/
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void *xRingbufferReceiveUpTo(RingbufHandle_t xRingbuffer, size_t *pxItemSize, TickType_t xTicksToWait, size_t xMaxSize);
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/**
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* @brief Retrieve bytes from a byte buffer, specifying the maximum amount of
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* bytes to retrieve. Call this from an ISR.
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*
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* Attempt to retrieve bytes from a byte buffer whilst specifying a maximum number
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* of bytes to retrieve. This function will return immediately if there is no data
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* available for retrieval.
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*
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* @param[in] xRingbuffer Ring buffer to retrieve the item from
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* @param[out] pxItemSize Pointer to a variable to which the size of the retrieved item will be written.
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* @param[in] xMaxSize Maximum number of bytes to return.
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*
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* @note A call to vRingbufferReturnItemFromISR() is required after this to free up the data received.
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* @note This function should only be called on byte buffers
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* @note Byte buffers do not allow multiple retrievals before returning an item
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*
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* @return
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* - Pointer to the retrieved item on success; *pxItemSize filled with
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* the length of the item.
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* - NULL when the ring buffer is empty, *pxItemSize is untouched in that case.
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*/
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void *xRingbufferReceiveUpToFromISR(RingbufHandle_t xRingbuffer, size_t *pxItemSize, size_t xMaxSize);
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/**
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* @brief Return a previously-retrieved item to the ring buffer
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*
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* @param[in] xRingbuffer Ring buffer the item was retrieved from
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* @param[in] pvItem Item that was received earlier
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*
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* @note If a split item is retrieved, both parts should be returned by calling this function twice
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*/
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void vRingbufferReturnItem(RingbufHandle_t xRingbuffer, void *pvItem);
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/**
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* @brief Return a previously-retrieved item to the ring buffer from an ISR
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*
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* @param[in] xRingbuffer Ring buffer the item was retrieved from
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* @param[in] pvItem Item that was received earlier
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* @param[out] pxHigherPriorityTaskWoken Value pointed to will be set to pdTRUE
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* if the function woke up a higher priority task.
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*
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* @note If a split item is retrieved, both parts should be returned by calling this function twice
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*/
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void vRingbufferReturnItemFromISR(RingbufHandle_t xRingbuffer, void *pvItem, BaseType_t *pxHigherPriorityTaskWoken);
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/**
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* @brief Delete a ring buffer
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*
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* @param[in] xRingbuffer Ring buffer to delete
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*/
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void vRingbufferDelete(RingbufHandle_t xRingbuffer);
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/**
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* @brief Get maximum size of an item that can be placed in the ring buffer
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*
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* This function returns the maximum size an item can have if it was placed in
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* an empty ring buffer.
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*
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* @param[in] xRingbuffer Ring buffer to query
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*
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* @return Maximum size, in bytes, of an item that can be placed in a ring buffer.
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*/
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size_t xRingbufferGetMaxItemSize(RingbufHandle_t xRingbuffer);
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/**
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* @brief Get current free size available for an item/data in the buffer
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*
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* This gives the real time free space available for an item/data in the ring
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* buffer. This represents the maximum size an item/data can have if it was
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* currently sent to the ring buffer.
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*
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* @warning This API is not thread safe. So, if multiple threads are accessing
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* the same ring buffer, it is the application's responsibility to
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* ensure atomic access to this API and the subsequent Send
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*
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* @param[in] xRingbuffer Ring buffer to query
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*
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* @return Current free size, in bytes, available for an entry
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*/
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size_t xRingbufferGetCurFreeSize(RingbufHandle_t xRingbuffer);
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/**
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* @brief Add the ring buffer's read semaphore to a queue set.
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*
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* The ring buffer's read semaphore indicates that data has been written
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* to the ring buffer. This function adds the ring buffer's read semaphore to
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* a queue set.
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*
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* @param[in] xRingbuffer Ring buffer to add to the queue set
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* @param[in] xQueueSet Queue set to add the ring buffer's read semaphore to
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*
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* @return
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* - pdTRUE on success, pdFALSE otherwise
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*/
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BaseType_t xRingbufferAddToQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet);
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/**
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* @brief Check if the selected queue set member is the ring buffer's read semaphore
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*
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* This API checks if queue set member returned from xQueueSelectFromSet()
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* is the read semaphore of this ring buffer. If so, this indicates the ring buffer
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* has items waiting to be retrieved.
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*
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* @param[in] xRingbuffer Ring buffer which should be checked
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* @param[in] xMember Member returned from xQueueSelectFromSet
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*
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* @return
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* - pdTRUE when semaphore belongs to ring buffer
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* - pdFALSE otherwise.
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*/
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BaseType_t xRingbufferCanRead(RingbufHandle_t xRingbuffer, QueueSetMemberHandle_t xMember);
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/**
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* @brief Remove the ring buffer's read semaphore from a queue set.
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*
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* This specifically removes a ring buffer's read semaphore from a queue set. The
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* read semaphore is used to indicate when data has been written to the ring buffer
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*
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* @param[in] xRingbuffer Ring buffer to remove from the queue set
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* @param[in] xQueueSet Queue set to remove the ring buffer's read semaphore from
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*
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* @return
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* - pdTRUE on success
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* - pdFALSE otherwise
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*/
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BaseType_t xRingbufferRemoveFromQueueSetRead(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet);
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/**
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* @brief Get information about ring buffer status
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*
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* Get information of the a ring buffer's current status such as
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* free/read/write pointer positions, and number of items waiting to be retrieved.
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* Arguments can be set to NULL if they are not required.
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*
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* @param[in] xRingbuffer Ring buffer to remove from the queue set
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* @param[out] uxFree Pointer use to store free pointer position
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* @param[out] uxRead Pointer use to store read pointer position
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* @param[out] uxWrite Pointer use to store write pointer position
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* @param[out] uxItemsWaiting Pointer use to store number of items (bytes for byte buffer) waiting to be retrieved
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*/
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void vRingbufferGetInfo(RingbufHandle_t xRingbuffer, UBaseType_t *uxFree, UBaseType_t *uxRead, UBaseType_t *uxWrite, UBaseType_t *uxItemsWaiting);
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/**
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* @brief Debugging function to print the internal pointers in the ring buffer
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*
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* @param xRingbuffer Ring buffer to show
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*/
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void xRingbufferPrintInfo(RingbufHandle_t xRingbuffer);
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/* -------------------------------- Deprecated Functions --------------------------- */
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/** @cond */ //Doxygen command to hide deprecated function from API Reference
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/*
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* Deprecated as function is not thread safe and does not check if an item is
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* actually available for retrieval. Use xRingbufferReceiveSplit() instead for
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* thread safe method of retrieve a split item.
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*/
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bool xRingbufferIsNextItemWrapped(RingbufHandle_t xRingbuffer) __attribute__((deprecated));
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/*
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* Deprecated as queue sets are not meant to be used for writing to buffers. Adding
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* the ring buffer write semaphore to a queue set will break queue set usage rules,
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* as every read of a semaphore must be preceded by a call to xQueueSelectFromSet().
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* QueueSetWrite no longer supported.
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*/
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BaseType_t xRingbufferAddToQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet) __attribute__((deprecated));
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/*
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* Deprecated as queue sets are not meant to be used for writing to buffers.
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* QueueSetWrite no longer supported.
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*/
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BaseType_t xRingbufferRemoveFromQueueSetWrite(RingbufHandle_t xRingbuffer, QueueSetHandle_t xQueueSet) __attribute__((deprecated));
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/** @endcond */
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#ifdef __cplusplus
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}
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#endif
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#endif /* FREERTOS_RINGBUF_H */
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