stream_buffer Struct Reference

Stream buffers are an RTOS task to RTOS task, and interrupt to task communication primitives. More...

#include <stream_buffer.hpp>

Public Types
using	size_type = etl::size_t

Public Member Functions
	stream_buffer (size_type size, size_type triggerLevel) noexcept
	Creates a new stream buffer using dynamically allocated memory.
	stream_buffer (stream_buffer &&other)=delete
	stream_buffer (stream_buffer const &other)=delete
	~stream_buffer () noexcept
	Deletes a stream buffer, then the allocated memory is freed.
auto	bytes_available () const noexcept -> size_type
	Queries a stream buffer to see how much data it contains, which is equal to the number of bytes that can be read from the stream buffer before the stream buffer would be empty.
auto	empty () const noexcept -> bool
	Queries a stream buffer to see if it is empty. A stream buffer is empty if it does not contain any data.
auto	full () const noexcept -> bool
	Queries a stream buffer to see if it is full. A stream buffer is full if it does not have any free space, and therefore cannot accept any more data.
auto	native_handle () const noexcept -> StreamBufferHandle_t
	Returns the native FreeRTOS handle to the stream_buffer.
auto	operator= (stream_buffer &&other) -> stream_buffer &=delete
auto	operator= (stream_buffer const &other) -> stream_buffer &=delete
auto	read (net::mutable_buffer data, TickType_t ticks) -> size_type
	Receives bytes from a stream buffer.
auto	read_from_isr (net::mutable_buffer data, BaseType_t *prio) -> size_type
	Receives bytes from a stream buffer.
auto	reset () noexcept -> void
	Resets a stream buffer to its initial, empty, state. Any data that was in the stream buffer is discarded. A stream buffer can only be reset if there are no tasks blocked waiting to either send to or receive from the stream buffer.
auto	space_available () const noexcept -> size_type
	Queries a stream buffer to see how much free space it contains, which is equal to the amount of data that can be sent to the stream buffer before it is full.
auto	trigger_level (size_type triggerLevel) noexcept -> void
	A stream buffer's trigger level is the number of bytes that must be in the stream buffer before a task that is blocked on the stream buffer to wait for data is moved out of the blocked state.
auto	write (net::const_buffer data, TickType_t ticks) -> size_type
	Sends bytes to a stream buffer. The bytes are copied into the stream buffer.
auto	write_from_isr (net::const_buffer data, BaseType_t *prio) -> size_type
	Interrupt safe version of the API function that sends a stream of bytes to the stream buffer.

Detailed Description

Stream buffers are an RTOS task to RTOS task, and interrupt to task communication primitives.

Unlike most other FreeRTOS communications primitives, they are optimised for single reader single writer scenarios, such as passing data from an interrupt service routine to a task, or from one microcontroller core to another on dual core CPUs. Data is passed by copy - the data is copied into the buffer by the sender and out of the buffer by the read.

https://www.freertos.org/RTOS-stream-buffer-API.html https://www.freertos.org/RTOS-stream-message-buffers.html

Member Typedef Documentation

size_type

using size_type = etl::size_t

Constructor & Destructor Documentation

stream_buffer() [1/3]

stream_buffer ( size_type size, size_type triggerLevel )

inlinenoexcept

Creates a new stream buffer using dynamically allocated memory.

https://www.freertos.org/xStreamBufferCreate.html

~stream_buffer()

~stream_buffer ( )

inlinenoexcept

Deletes a stream buffer, then the allocated memory is freed.

https://www.freertos.org/vStreamBufferDelete.html

stream_buffer() [2/3]

stream_buffer ( stream_buffer const & other )

delete

stream_buffer() [3/3]

stream_buffer ( stream_buffer && other )

delete

Member Function Documentation

bytes_available()

auto bytes_available ( ) const -> size_type

inlinenodiscardnoexcept

Queries a stream buffer to see how much data it contains, which is equal to the number of bytes that can be read from the stream buffer before the stream buffer would be empty.

https://www.freertos.org/xStreamBufferBytesAvailable.html

empty()

auto empty ( ) const -> bool

inlinenodiscardnoexcept

Queries a stream buffer to see if it is empty. A stream buffer is empty if it does not contain any data.

https://www.freertos.org/xStreamBufferIsEmpty.html

full()

auto full ( ) const -> bool

inlinenodiscardnoexcept

Queries a stream buffer to see if it is full. A stream buffer is full if it does not have any free space, and therefore cannot accept any more data.

https://www.freertos.org/xStreamBufferIsFull.html

native_handle()

auto native_handle ( ) const -> StreamBufferHandle_t

inlinenodiscardnoexcept

Returns the native FreeRTOS handle to the stream_buffer.

operator=() [1/2]

auto operator= ( stream_buffer && other ) -> stream_buffer &=delete

delete

operator=() [2/2]

auto operator= ( stream_buffer const & other ) -> stream_buffer &=delete

delete

read()

auto read ( net::mutable_buffer data, TickType_t ticks ) -> size_type

inline

Receives bytes from a stream buffer.

https://www.freertos.org/xStreamBufferReceive.html

read_from_isr()

auto read_from_isr ( net::mutable_buffer data, BaseType_t * prio ) -> size_type

inline

Receives bytes from a stream buffer.

https://www.freertos.org/xStreamBufferReceiveFromISR.html

reset()

auto reset ( ) -> void

inlinenoexcept

Resets a stream buffer to its initial, empty, state. Any data that was in the stream buffer is discarded. A stream buffer can only be reset if there are no tasks blocked waiting to either send to or receive from the stream buffer.

https://www.freertos.org/xStreamBufferReset.html

space_available()

auto space_available ( ) const -> size_type

inlinenodiscardnoexcept

Queries a stream buffer to see how much free space it contains, which is equal to the amount of data that can be sent to the stream buffer before it is full.

https://www.freertos.org/xStreamBufferSpacesAvailable.html

trigger_level()

auto trigger_level ( size_type triggerLevel ) -> void

inlinenoexcept

A stream buffer's trigger level is the number of bytes that must be in the stream buffer before a task that is blocked on the stream buffer to wait for data is moved out of the blocked state.

For example, if a task is blocked on a read of an empty stream buffer that has a trigger level of 1 then the task will be unblocked when a single byte is written to the buffer or the task's block time expires. As another example, if a task is blocked on a read of an empty stream buffer that has a trigger level of 10 then the task will not be unblocked until the stream buffer contains at least 10 bytes or the task's block time expires. If a reading task's block time expires before the trigger level is reached then the task will still receive however many bytes are actually available. Setting a trigger level of 0 will result in a trigger level of 1 being used. It is not valid to specify a trigger level that is greater than the buffer size.

https://www.freertos.org/xStreamBufferSetTriggerLevel.html

write()

auto write ( net::const_buffer data, TickType_t ticks ) -> size_type

inline

Sends bytes to a stream buffer. The bytes are copied into the stream buffer.

https://www.freertos.org/xStreamBufferSend.html

write_from_isr()

auto write_from_isr ( net::const_buffer data, BaseType_t * prio ) -> size_type

inline

Interrupt safe version of the API function that sends a stream of bytes to the stream buffer.

https://www.freertos.org/xStreamBufferSendFromISR.html

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The documentation for this struct was generated from the following file:

• include/etl/experimental/freertos/stream_buffer.hpp