860 lines
38 KiB
C
860 lines
38 KiB
C
/*
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* FreeRTOS Kernel V10.3.1
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*
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* Stream buffers are used to send a continuous stream of data from one task or
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* interrupt to another. Their implementation is light weight, making them
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* particularly suited for interrupt to task and core to core communication
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* scenarios.
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*
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* ***NOTE***: Uniquely among FreeRTOS objects, the stream buffer
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* implementation (so also the message buffer implementation, as message buffers
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* are built on top of stream buffers) assumes there is only one task or
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* interrupt that will write to the buffer (the writer), and only one task or
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* interrupt that will read from the buffer (the reader). It is safe for the
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* writer and reader to be different tasks or interrupts, but, unlike other
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* FreeRTOS objects, it is not safe to have multiple different writers or
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* multiple different readers. If there are to be multiple different writers
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* then the application writer must place each call to a writing API function
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* (such as xStreamBufferSend()) inside a critical section and set the send
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* block time to 0. Likewise, if there are to be multiple different readers
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* then the application writer must place each call to a reading API function
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* (such as xStreamBufferReceive()) inside a critical section section and set the
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* receive block time to 0.
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*
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*/
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#ifndef STREAM_BUFFER_H
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#define STREAM_BUFFER_H
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#ifndef INC_FREERTOS_H
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#error "include FreeRTOS.h must appear in source files before include stream_buffer.h"
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#endif
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#if defined( __cplusplus )
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extern "C" {
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#endif
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/**
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* Type by which stream buffers are referenced. For example, a call to
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* xStreamBufferCreate() returns an StreamBufferHandle_t variable that can
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* then be used as a parameter to xStreamBufferSend(), xStreamBufferReceive(),
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* etc.
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*/
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struct StreamBufferDef_t;
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typedef struct StreamBufferDef_t * StreamBufferHandle_t;
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/**
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* message_buffer.h
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*
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<pre>
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StreamBufferHandle_t xStreamBufferCreate( size_t xBufferSizeBytes, size_t xTriggerLevelBytes );
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</pre>
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*
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* Creates a new stream buffer using dynamically allocated memory. See
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* xStreamBufferCreateStatic() for a version that uses statically allocated
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* memory (memory that is allocated at compile time).
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*
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* configSUPPORT_DYNAMIC_ALLOCATION must be set to 1 or left undefined in
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* FreeRTOSConfig.h for xStreamBufferCreate() to be available.
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*
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* @param xBufferSizeBytes The total number of bytes the stream buffer will be
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* able to hold at any one time.
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*
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* @param xTriggerLevelBytes The number of bytes that must be in the stream
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* buffer before a task that is blocked on the stream buffer to wait for data is
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* moved out of the blocked state. For example, if a task is blocked on a read
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* of an empty stream buffer that has a trigger level of 1 then the task will be
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* unblocked when a single byte is written to the buffer or the task's block
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* time expires. As another example, if a task is blocked on a read of an empty
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* stream buffer that has a trigger level of 10 then the task will not be
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* unblocked until the stream buffer contains at least 10 bytes or the task's
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* block time expires. If a reading task's block time expires before the
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* trigger level is reached then the task will still receive however many bytes
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* are actually available. Setting a trigger level of 0 will result in a
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* trigger level of 1 being used. It is not valid to specify a trigger level
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* that is greater than the buffer size.
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*
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* @return If NULL is returned, then the stream buffer cannot be created
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* because there is insufficient heap memory available for FreeRTOS to allocate
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* the stream buffer data structures and storage area. A non-NULL value being
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* returned indicates that the stream buffer has been created successfully -
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* the returned value should be stored as the handle to the created stream
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* buffer.
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*
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* Example use:
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<pre>
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void vAFunction( void )
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{
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StreamBufferHandle_t xStreamBuffer;
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const size_t xStreamBufferSizeBytes = 100, xTriggerLevel = 10;
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// Create a stream buffer that can hold 100 bytes. The memory used to hold
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// both the stream buffer structure and the data in the stream buffer is
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// allocated dynamically.
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xStreamBuffer = xStreamBufferCreate( xStreamBufferSizeBytes, xTriggerLevel );
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if( xStreamBuffer == NULL )
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{
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// There was not enough heap memory space available to create the
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// stream buffer.
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}
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else
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{
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// The stream buffer was created successfully and can now be used.
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}
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}
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</pre>
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* \defgroup xStreamBufferCreate xStreamBufferCreate
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* \ingroup StreamBufferManagement
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*/
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#define xStreamBufferCreate( xBufferSizeBytes, xTriggerLevelBytes ) xStreamBufferGenericCreate( xBufferSizeBytes, xTriggerLevelBytes, pdFALSE )
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/**
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* stream_buffer.h
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*
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<pre>
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StreamBufferHandle_t xStreamBufferCreateStatic( size_t xBufferSizeBytes,
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size_t xTriggerLevelBytes,
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uint8_t *pucStreamBufferStorageArea,
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StaticStreamBuffer_t *pxStaticStreamBuffer );
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</pre>
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* Creates a new stream buffer using statically allocated memory. See
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* xStreamBufferCreate() for a version that uses dynamically allocated memory.
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*
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* configSUPPORT_STATIC_ALLOCATION must be set to 1 in FreeRTOSConfig.h for
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* xStreamBufferCreateStatic() to be available.
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*
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* @param xBufferSizeBytes The size, in bytes, of the buffer pointed to by the
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* pucStreamBufferStorageArea parameter.
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*
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* @param xTriggerLevelBytes The number of bytes that must be in the stream
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* buffer before a task that is blocked on the stream buffer to wait for data is
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* moved out of the blocked state. For example, if a task is blocked on a read
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* of an empty stream buffer that has a trigger level of 1 then the task will be
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* unblocked when a single byte is written to the buffer or the task's block
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* time expires. As another example, if a task is blocked on a read of an empty
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* stream buffer that has a trigger level of 10 then the task will not be
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* unblocked until the stream buffer contains at least 10 bytes or the task's
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* block time expires. If a reading task's block time expires before the
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* trigger level is reached then the task will still receive however many bytes
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* are actually available. Setting a trigger level of 0 will result in a
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* trigger level of 1 being used. It is not valid to specify a trigger level
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* that is greater than the buffer size.
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*
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* @param pucStreamBufferStorageArea Must point to a uint8_t array that is at
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* least xBufferSizeBytes + 1 big. This is the array to which streams are
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* copied when they are written to the stream buffer.
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*
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* @param pxStaticStreamBuffer Must point to a variable of type
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* StaticStreamBuffer_t, which will be used to hold the stream buffer's data
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* structure.
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*
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* @return If the stream buffer is created successfully then a handle to the
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* created stream buffer is returned. If either pucStreamBufferStorageArea or
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* pxStaticstreamBuffer are NULL then NULL is returned.
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*
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* Example use:
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<pre>
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// Used to dimension the array used to hold the streams. The available space
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// will actually be one less than this, so 999.
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#define STORAGE_SIZE_BYTES 1000
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// Defines the memory that will actually hold the streams within the stream
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// buffer.
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static uint8_t ucStorageBuffer[ STORAGE_SIZE_BYTES ];
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// The variable used to hold the stream buffer structure.
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StaticStreamBuffer_t xStreamBufferStruct;
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void MyFunction( void )
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{
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StreamBufferHandle_t xStreamBuffer;
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const size_t xTriggerLevel = 1;
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xStreamBuffer = xStreamBufferCreateStatic( sizeof( ucBufferStorage ),
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xTriggerLevel,
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ucBufferStorage,
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&xStreamBufferStruct );
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// As neither the pucStreamBufferStorageArea or pxStaticStreamBuffer
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// parameters were NULL, xStreamBuffer will not be NULL, and can be used to
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// reference the created stream buffer in other stream buffer API calls.
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// Other code that uses the stream buffer can go here.
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}
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</pre>
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* \defgroup xStreamBufferCreateStatic xStreamBufferCreateStatic
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* \ingroup StreamBufferManagement
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*/
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#define xStreamBufferCreateStatic( xBufferSizeBytes, xTriggerLevelBytes, pucStreamBufferStorageArea, pxStaticStreamBuffer ) xStreamBufferGenericCreateStatic( xBufferSizeBytes, xTriggerLevelBytes, pdFALSE, pucStreamBufferStorageArea, pxStaticStreamBuffer )
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/**
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* stream_buffer.h
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*
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<pre>
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size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
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const void *pvTxData,
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size_t xDataLengthBytes,
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TickType_t xTicksToWait );
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</pre>
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*
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* Sends bytes to a stream buffer. The bytes are copied into the stream buffer.
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*
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* ***NOTE***: Uniquely among FreeRTOS objects, the stream buffer
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* implementation (so also the message buffer implementation, as message buffers
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* are built on top of stream buffers) assumes there is only one task or
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* interrupt that will write to the buffer (the writer), and only one task or
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* interrupt that will read from the buffer (the reader). It is safe for the
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* writer and reader to be different tasks or interrupts, but, unlike other
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* FreeRTOS objects, it is not safe to have multiple different writers or
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* multiple different readers. If there are to be multiple different writers
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* then the application writer must place each call to a writing API function
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* (such as xStreamBufferSend()) inside a critical section and set the send
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* block time to 0. Likewise, if there are to be multiple different readers
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* then the application writer must place each call to a reading API function
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* (such as xStreamBufferReceive()) inside a critical section and set the receive
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* block time to 0.
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*
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* Use xStreamBufferSend() to write to a stream buffer from a task. Use
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* xStreamBufferSendFromISR() to write to a stream buffer from an interrupt
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* service routine (ISR).
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*
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* @param xStreamBuffer The handle of the stream buffer to which a stream is
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* being sent.
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*
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* @param pvTxData A pointer to the buffer that holds the bytes to be copied
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* into the stream buffer.
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*
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* @param xDataLengthBytes The maximum number of bytes to copy from pvTxData
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* into the stream buffer.
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*
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* @param xTicksToWait The maximum amount of time the task should remain in the
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* Blocked state to wait for enough space to become available in the stream
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* buffer, should the stream buffer contain too little space to hold the
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* another xDataLengthBytes bytes. The block time is specified in tick periods,
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* so the absolute time it represents is dependent on the tick frequency. The
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* macro pdMS_TO_TICKS() can be used to convert a time specified in milliseconds
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* into a time specified in ticks. Setting xTicksToWait to portMAX_DELAY will
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* cause the task to wait indefinitely (without timing out), provided
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* INCLUDE_vTaskSuspend is set to 1 in FreeRTOSConfig.h. If a task times out
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* before it can write all xDataLengthBytes into the buffer it will still write
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* as many bytes as possible. A task does not use any CPU time when it is in
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* the blocked state.
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*
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* @return The number of bytes written to the stream buffer. If a task times
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* out before it can write all xDataLengthBytes into the buffer it will still
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* write as many bytes as possible.
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*
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* Example use:
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<pre>
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void vAFunction( StreamBufferHandle_t xStreamBuffer )
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{
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size_t xBytesSent;
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uint8_t ucArrayToSend[] = { 0, 1, 2, 3 };
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char *pcStringToSend = "String to send";
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const TickType_t x100ms = pdMS_TO_TICKS( 100 );
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// Send an array to the stream buffer, blocking for a maximum of 100ms to
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// wait for enough space to be available in the stream buffer.
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xBytesSent = xStreamBufferSend( xStreamBuffer, ( void * ) ucArrayToSend, sizeof( ucArrayToSend ), x100ms );
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if( xBytesSent != sizeof( ucArrayToSend ) )
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{
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// The call to xStreamBufferSend() times out before there was enough
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// space in the buffer for the data to be written, but it did
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// successfully write xBytesSent bytes.
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}
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// Send the string to the stream buffer. Return immediately if there is not
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// enough space in the buffer.
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xBytesSent = xStreamBufferSend( xStreamBuffer, ( void * ) pcStringToSend, strlen( pcStringToSend ), 0 );
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if( xBytesSent != strlen( pcStringToSend ) )
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{
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// The entire string could not be added to the stream buffer because
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// there was not enough free space in the buffer, but xBytesSent bytes
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// were sent. Could try again to send the remaining bytes.
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}
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}
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</pre>
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* \defgroup xStreamBufferSend xStreamBufferSend
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* \ingroup StreamBufferManagement
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*/
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size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
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const void *pvTxData,
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size_t xDataLengthBytes,
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TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
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/**
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* stream_buffer.h
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*
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<pre>
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size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
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const void *pvTxData,
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size_t xDataLengthBytes,
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BaseType_t *pxHigherPriorityTaskWoken );
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</pre>
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*
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* Interrupt safe version of the API function that sends a stream of bytes to
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* the stream buffer.
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*
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* ***NOTE***: Uniquely among FreeRTOS objects, the stream buffer
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* implementation (so also the message buffer implementation, as message buffers
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* are built on top of stream buffers) assumes there is only one task or
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* interrupt that will write to the buffer (the writer), and only one task or
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* interrupt that will read from the buffer (the reader). It is safe for the
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* writer and reader to be different tasks or interrupts, but, unlike other
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* FreeRTOS objects, it is not safe to have multiple different writers or
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* multiple different readers. If there are to be multiple different writers
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* then the application writer must place each call to a writing API function
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* (such as xStreamBufferSend()) inside a critical section and set the send
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* block time to 0. Likewise, if there are to be multiple different readers
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* then the application writer must place each call to a reading API function
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* (such as xStreamBufferReceive()) inside a critical section and set the receive
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* block time to 0.
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*
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* Use xStreamBufferSend() to write to a stream buffer from a task. Use
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* xStreamBufferSendFromISR() to write to a stream buffer from an interrupt
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* service routine (ISR).
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*
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* @param xStreamBuffer The handle of the stream buffer to which a stream is
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* being sent.
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*
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* @param pvTxData A pointer to the data that is to be copied into the stream
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* buffer.
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*
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* @param xDataLengthBytes The maximum number of bytes to copy from pvTxData
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* into the stream buffer.
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*
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* @param pxHigherPriorityTaskWoken It is possible that a stream buffer will
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* have a task blocked on it waiting for data. Calling
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* xStreamBufferSendFromISR() can make data available, and so cause a task that
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* was waiting for data to leave the Blocked state. If calling
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* xStreamBufferSendFromISR() causes a task to leave the Blocked state, and the
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* unblocked task has a priority higher than the currently executing task (the
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* task that was interrupted), then, internally, xStreamBufferSendFromISR()
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* will set *pxHigherPriorityTaskWoken to pdTRUE. If
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* xStreamBufferSendFromISR() sets this value to pdTRUE, then normally a
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* context switch should be performed before the interrupt is exited. This will
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* ensure that the interrupt returns directly to the highest priority Ready
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* state task. *pxHigherPriorityTaskWoken should be set to pdFALSE before it
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* is passed into the function. See the example code below for an example.
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*
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* @return The number of bytes actually written to the stream buffer, which will
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* be less than xDataLengthBytes if the stream buffer didn't have enough free
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* space for all the bytes to be written.
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*
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* Example use:
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<pre>
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// A stream buffer that has already been created.
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StreamBufferHandle_t xStreamBuffer;
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void vAnInterruptServiceRoutine( void )
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{
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size_t xBytesSent;
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char *pcStringToSend = "String to send";
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BaseType_t xHigherPriorityTaskWoken = pdFALSE; // Initialised to pdFALSE.
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// Attempt to send the string to the stream buffer.
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xBytesSent = xStreamBufferSendFromISR( xStreamBuffer,
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( void * ) pcStringToSend,
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strlen( pcStringToSend ),
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&xHigherPriorityTaskWoken );
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if( xBytesSent != strlen( pcStringToSend ) )
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{
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// There was not enough free space in the stream buffer for the entire
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// string to be written, ut xBytesSent bytes were written.
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}
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// If xHigherPriorityTaskWoken was set to pdTRUE inside
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// xStreamBufferSendFromISR() then a task that has a priority above the
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// priority of the currently executing task was unblocked and a context
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// switch should be performed to ensure the ISR returns to the unblocked
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// task. In most FreeRTOS ports this is done by simply passing
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// xHigherPriorityTaskWoken into taskYIELD_FROM_ISR(), which will test the
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// variables value, and perform the context switch if necessary. Check the
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// documentation for the port in use for port specific instructions.
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taskYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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}
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</pre>
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* \defgroup xStreamBufferSendFromISR xStreamBufferSendFromISR
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* \ingroup StreamBufferManagement
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*/
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size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
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const void *pvTxData,
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size_t xDataLengthBytes,
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BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
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/**
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* stream_buffer.h
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*
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<pre>
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size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
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void *pvRxData,
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size_t xBufferLengthBytes,
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TickType_t xTicksToWait );
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</pre>
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*
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* Receives bytes from a stream buffer.
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*
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* ***NOTE***: Uniquely among FreeRTOS objects, the stream buffer
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|
* implementation (so also the message buffer implementation, as message buffers
|
|
* are built on top of stream buffers) assumes there is only one task or
|
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* interrupt that will write to the buffer (the writer), and only one task or
|
|
* interrupt that will read from the buffer (the reader). It is safe for the
|
|
* writer and reader to be different tasks or interrupts, but, unlike other
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|
* FreeRTOS objects, it is not safe to have multiple different writers or
|
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* multiple different readers. If there are to be multiple different writers
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* then the application writer must place each call to a writing API function
|
|
* (such as xStreamBufferSend()) inside a critical section and set the send
|
|
* block time to 0. Likewise, if there are to be multiple different readers
|
|
* then the application writer must place each call to a reading API function
|
|
* (such as xStreamBufferReceive()) inside a critical section and set the receive
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|
* block time to 0.
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*
|
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* Use xStreamBufferReceive() to read from a stream buffer from a task. Use
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* xStreamBufferReceiveFromISR() to read from a stream buffer from an
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* interrupt service routine (ISR).
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*
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* @param xStreamBuffer The handle of the stream buffer from which bytes are to
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* be received.
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*
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* @param pvRxData A pointer to the buffer into which the received bytes will be
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* copied.
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|
*
|
|
* @param xBufferLengthBytes The length of the buffer pointed to by the
|
|
* pvRxData parameter. This sets the maximum number of bytes to receive in one
|
|
* call. xStreamBufferReceive will return as many bytes as possible up to a
|
|
* maximum set by xBufferLengthBytes.
|
|
*
|
|
* @param xTicksToWait The maximum amount of time the task should remain in the
|
|
* Blocked state to wait for data to become available if the stream buffer is
|
|
* empty. xStreamBufferReceive() will return immediately if xTicksToWait is
|
|
* zero. The block time is specified in tick periods, so the absolute time it
|
|
* represents is dependent on the tick frequency. The macro pdMS_TO_TICKS() can
|
|
* be used to convert a time specified in milliseconds into a time specified in
|
|
* ticks. Setting xTicksToWait to portMAX_DELAY will cause the task to wait
|
|
* indefinitely (without timing out), provided INCLUDE_vTaskSuspend is set to 1
|
|
* in FreeRTOSConfig.h. A task does not use any CPU time when it is in the
|
|
* Blocked state.
|
|
*
|
|
* @return The number of bytes actually read from the stream buffer, which will
|
|
* be less than xBufferLengthBytes if the call to xStreamBufferReceive() timed
|
|
* out before xBufferLengthBytes were available.
|
|
*
|
|
* Example use:
|
|
<pre>
|
|
void vAFunction( StreamBuffer_t xStreamBuffer )
|
|
{
|
|
uint8_t ucRxData[ 20 ];
|
|
size_t xReceivedBytes;
|
|
const TickType_t xBlockTime = pdMS_TO_TICKS( 20 );
|
|
|
|
// Receive up to another sizeof( ucRxData ) bytes from the stream buffer.
|
|
// Wait in the Blocked state (so not using any CPU processing time) for a
|
|
// maximum of 100ms for the full sizeof( ucRxData ) number of bytes to be
|
|
// available.
|
|
xReceivedBytes = xStreamBufferReceive( xStreamBuffer,
|
|
( void * ) ucRxData,
|
|
sizeof( ucRxData ),
|
|
xBlockTime );
|
|
|
|
if( xReceivedBytes > 0 )
|
|
{
|
|
// A ucRxData contains another xRecievedBytes bytes of data, which can
|
|
// be processed here....
|
|
}
|
|
}
|
|
</pre>
|
|
* \defgroup xStreamBufferReceive xStreamBufferReceive
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
|
|
void *pvRxData,
|
|
size_t xBufferLengthBytes,
|
|
TickType_t xTicksToWait ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
|
|
void *pvRxData,
|
|
size_t xBufferLengthBytes,
|
|
BaseType_t *pxHigherPriorityTaskWoken );
|
|
</pre>
|
|
*
|
|
* An interrupt safe version of the API function that receives bytes from a
|
|
* stream buffer.
|
|
*
|
|
* Use xStreamBufferReceive() to read bytes from a stream buffer from a task.
|
|
* Use xStreamBufferReceiveFromISR() to read bytes from a stream buffer from an
|
|
* interrupt service routine (ISR).
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer from which a stream
|
|
* is being received.
|
|
*
|
|
* @param pvRxData A pointer to the buffer into which the received bytes are
|
|
* copied.
|
|
*
|
|
* @param xBufferLengthBytes The length of the buffer pointed to by the
|
|
* pvRxData parameter. This sets the maximum number of bytes to receive in one
|
|
* call. xStreamBufferReceive will return as many bytes as possible up to a
|
|
* maximum set by xBufferLengthBytes.
|
|
*
|
|
* @param pxHigherPriorityTaskWoken It is possible that a stream buffer will
|
|
* have a task blocked on it waiting for space to become available. Calling
|
|
* xStreamBufferReceiveFromISR() can make space available, and so cause a task
|
|
* that is waiting for space to leave the Blocked state. If calling
|
|
* xStreamBufferReceiveFromISR() causes a task to leave the Blocked state, and
|
|
* the unblocked task has a priority higher than the currently executing task
|
|
* (the task that was interrupted), then, internally,
|
|
* xStreamBufferReceiveFromISR() will set *pxHigherPriorityTaskWoken to pdTRUE.
|
|
* If xStreamBufferReceiveFromISR() sets this value to pdTRUE, then normally a
|
|
* context switch should be performed before the interrupt is exited. That will
|
|
* ensure the interrupt returns directly to the highest priority Ready state
|
|
* task. *pxHigherPriorityTaskWoken should be set to pdFALSE before it is
|
|
* passed into the function. See the code example below for an example.
|
|
*
|
|
* @return The number of bytes read from the stream buffer, if any.
|
|
*
|
|
* Example use:
|
|
<pre>
|
|
// A stream buffer that has already been created.
|
|
StreamBuffer_t xStreamBuffer;
|
|
|
|
void vAnInterruptServiceRoutine( void )
|
|
{
|
|
uint8_t ucRxData[ 20 ];
|
|
size_t xReceivedBytes;
|
|
BaseType_t xHigherPriorityTaskWoken = pdFALSE; // Initialised to pdFALSE.
|
|
|
|
// Receive the next stream from the stream buffer.
|
|
xReceivedBytes = xStreamBufferReceiveFromISR( xStreamBuffer,
|
|
( void * ) ucRxData,
|
|
sizeof( ucRxData ),
|
|
&xHigherPriorityTaskWoken );
|
|
|
|
if( xReceivedBytes > 0 )
|
|
{
|
|
// ucRxData contains xReceivedBytes read from the stream buffer.
|
|
// Process the stream here....
|
|
}
|
|
|
|
// If xHigherPriorityTaskWoken was set to pdTRUE inside
|
|
// xStreamBufferReceiveFromISR() then a task that has a priority above the
|
|
// priority of the currently executing task was unblocked and a context
|
|
// switch should be performed to ensure the ISR returns to the unblocked
|
|
// task. In most FreeRTOS ports this is done by simply passing
|
|
// xHigherPriorityTaskWoken into taskYIELD_FROM_ISR(), which will test the
|
|
// variables value, and perform the context switch if necessary. Check the
|
|
// documentation for the port in use for port specific instructions.
|
|
taskYIELD_FROM_ISR( xHigherPriorityTaskWoken );
|
|
}
|
|
</pre>
|
|
* \defgroup xStreamBufferReceiveFromISR xStreamBufferReceiveFromISR
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
|
|
void *pvRxData,
|
|
size_t xBufferLengthBytes,
|
|
BaseType_t * const pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* Deletes a stream buffer that was previously created using a call to
|
|
* xStreamBufferCreate() or xStreamBufferCreateStatic(). If the stream
|
|
* buffer was created using dynamic memory (that is, by xStreamBufferCreate()),
|
|
* then the allocated memory is freed.
|
|
*
|
|
* A stream buffer handle must not be used after the stream buffer has been
|
|
* deleted.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer to be deleted.
|
|
*
|
|
* \defgroup vStreamBufferDelete vStreamBufferDelete
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferIsFull( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* 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.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being queried.
|
|
*
|
|
* @return If the stream buffer is full then pdTRUE is returned. Otherwise
|
|
* pdFALSE is returned.
|
|
*
|
|
* \defgroup xStreamBufferIsFull xStreamBufferIsFull
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferIsFull( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferIsEmpty( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* Queries a stream buffer to see if it is empty. A stream buffer is empty if
|
|
* it does not contain any data.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being queried.
|
|
*
|
|
* @return If the stream buffer is empty then pdTRUE is returned. Otherwise
|
|
* pdFALSE is returned.
|
|
*
|
|
* \defgroup xStreamBufferIsEmpty xStreamBufferIsEmpty
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferIsEmpty( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* 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.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being reset.
|
|
*
|
|
* @return If the stream buffer is reset then pdPASS is returned. If there was
|
|
* a task blocked waiting to send to or read from the stream buffer then the
|
|
* stream buffer is not reset and pdFAIL is returned.
|
|
*
|
|
* \defgroup xStreamBufferReset xStreamBufferReset
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* 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.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being queried.
|
|
*
|
|
* @return The number of bytes that can be written to the stream buffer before
|
|
* the stream buffer would be full.
|
|
*
|
|
* \defgroup xStreamBufferSpacesAvailable xStreamBufferSpacesAvailable
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer );
|
|
</pre>
|
|
*
|
|
* 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.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being queried.
|
|
*
|
|
* @return The number of bytes that can be read from the stream buffer before
|
|
* the stream buffer would be empty.
|
|
*
|
|
* \defgroup xStreamBufferBytesAvailable xStreamBufferBytesAvailable
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer, size_t xTriggerLevel );
|
|
</pre>
|
|
*
|
|
* 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.
|
|
*
|
|
* A trigger level is set when the stream buffer is created, and can be modified
|
|
* using xStreamBufferSetTriggerLevel().
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer being updated.
|
|
*
|
|
* @param xTriggerLevel The new trigger level for the stream buffer.
|
|
*
|
|
* @return If xTriggerLevel was less than or equal to the stream buffer's length
|
|
* then the trigger level will be updated and pdTRUE is returned. Otherwise
|
|
* pdFALSE is returned.
|
|
*
|
|
* \defgroup xStreamBufferSetTriggerLevel xStreamBufferSetTriggerLevel
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer, size_t xTriggerLevel ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferSendCompletedFromISR( StreamBufferHandle_t xStreamBuffer, BaseType_t *pxHigherPriorityTaskWoken );
|
|
</pre>
|
|
*
|
|
* For advanced users only.
|
|
*
|
|
* The sbSEND_COMPLETED() macro is called from within the FreeRTOS APIs when
|
|
* data is sent to a message buffer or stream buffer. If there was a task that
|
|
* was blocked on the message or stream buffer waiting for data to arrive then
|
|
* the sbSEND_COMPLETED() macro sends a notification to the task to remove it
|
|
* from the Blocked state. xStreamBufferSendCompletedFromISR() does the same
|
|
* thing. It is provided to enable application writers to implement their own
|
|
* version of sbSEND_COMPLETED(), and MUST NOT BE USED AT ANY OTHER TIME.
|
|
*
|
|
* See the example implemented in FreeRTOS/Demo/Minimal/MessageBufferAMP.c for
|
|
* additional information.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer to which data was
|
|
* written.
|
|
*
|
|
* @param pxHigherPriorityTaskWoken *pxHigherPriorityTaskWoken should be
|
|
* initialised to pdFALSE before it is passed into
|
|
* xStreamBufferSendCompletedFromISR(). If calling
|
|
* xStreamBufferSendCompletedFromISR() removes a task from the Blocked state,
|
|
* and the task has a priority above the priority of the currently running task,
|
|
* then *pxHigherPriorityTaskWoken will get set to pdTRUE indicating that a
|
|
* context switch should be performed before exiting the ISR.
|
|
*
|
|
* @return If a task was removed from the Blocked state then pdTRUE is returned.
|
|
* Otherwise pdFALSE is returned.
|
|
*
|
|
* \defgroup xStreamBufferSendCompletedFromISR xStreamBufferSendCompletedFromISR
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferSendCompletedFromISR( StreamBufferHandle_t xStreamBuffer, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
|
|
|
|
/**
|
|
* stream_buffer.h
|
|
*
|
|
<pre>
|
|
BaseType_t xStreamBufferReceiveCompletedFromISR( StreamBufferHandle_t xStreamBuffer, BaseType_t *pxHigherPriorityTaskWoken );
|
|
</pre>
|
|
*
|
|
* For advanced users only.
|
|
*
|
|
* The sbRECEIVE_COMPLETED() macro is called from within the FreeRTOS APIs when
|
|
* data is read out of a message buffer or stream buffer. If there was a task
|
|
* that was blocked on the message or stream buffer waiting for data to arrive
|
|
* then the sbRECEIVE_COMPLETED() macro sends a notification to the task to
|
|
* remove it from the Blocked state. xStreamBufferReceiveCompletedFromISR()
|
|
* does the same thing. It is provided to enable application writers to
|
|
* implement their own version of sbRECEIVE_COMPLETED(), and MUST NOT BE USED AT
|
|
* ANY OTHER TIME.
|
|
*
|
|
* See the example implemented in FreeRTOS/Demo/Minimal/MessageBufferAMP.c for
|
|
* additional information.
|
|
*
|
|
* @param xStreamBuffer The handle of the stream buffer from which data was
|
|
* read.
|
|
*
|
|
* @param pxHigherPriorityTaskWoken *pxHigherPriorityTaskWoken should be
|
|
* initialised to pdFALSE before it is passed into
|
|
* xStreamBufferReceiveCompletedFromISR(). If calling
|
|
* xStreamBufferReceiveCompletedFromISR() removes a task from the Blocked state,
|
|
* and the task has a priority above the priority of the currently running task,
|
|
* then *pxHigherPriorityTaskWoken will get set to pdTRUE indicating that a
|
|
* context switch should be performed before exiting the ISR.
|
|
*
|
|
* @return If a task was removed from the Blocked state then pdTRUE is returned.
|
|
* Otherwise pdFALSE is returned.
|
|
*
|
|
* \defgroup xStreamBufferReceiveCompletedFromISR xStreamBufferReceiveCompletedFromISR
|
|
* \ingroup StreamBufferManagement
|
|
*/
|
|
BaseType_t xStreamBufferReceiveCompletedFromISR( StreamBufferHandle_t xStreamBuffer, BaseType_t *pxHigherPriorityTaskWoken ) PRIVILEGED_FUNCTION;
|
|
|
|
/* Functions below here are not part of the public API. */
|
|
StreamBufferHandle_t xStreamBufferGenericCreate( size_t xBufferSizeBytes,
|
|
size_t xTriggerLevelBytes,
|
|
BaseType_t xIsMessageBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
StreamBufferHandle_t xStreamBufferGenericCreateStatic( size_t xBufferSizeBytes,
|
|
size_t xTriggerLevelBytes,
|
|
BaseType_t xIsMessageBuffer,
|
|
uint8_t * const pucStreamBufferStorageArea,
|
|
StaticStreamBuffer_t * const pxStaticStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
size_t xStreamBufferNextMessageLengthBytes( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
|
|
#if( configUSE_TRACE_FACILITY == 1 )
|
|
void vStreamBufferSetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer, UBaseType_t uxStreamBufferNumber ) PRIVILEGED_FUNCTION;
|
|
UBaseType_t uxStreamBufferGetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
uint8_t ucStreamBufferGetStreamBufferType( StreamBufferHandle_t xStreamBuffer ) PRIVILEGED_FUNCTION;
|
|
#endif
|
|
|
|
#if defined( __cplusplus )
|
|
}
|
|
#endif
|
|
|
|
#endif /* !defined( STREAM_BUFFER_H ) */
|