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stream_buffer.c
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/*
* FreeRTOS Kernel V10.3.1
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
*/
/* Standard includes. */
#include <stdint.h>
#include <string.h>
/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
* all the API functions to use the MPU wrappers. That should only be done when
* task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "stream_buffer.h"
#if ( configUSE_TASK_NOTIFICATIONS != 1 )
#error configUSE_TASK_NOTIFICATIONS must be set to 1 to build stream_buffer.c
#endif
/* Lint e961, e9021 and e750 are suppressed as a MISRA exception justified
* because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
* for the header files above, but not in this file, in order to generate the
* correct privileged Vs unprivileged linkage and placement. */
#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750 !e9021. */
/* If the user has not provided application specific Rx notification macros,
* or #defined the notification macros away, them provide default implementations
* that uses task notifications. */
/*lint -save -e9026 Function like macros allowed and needed here so they can be overidden. */
#ifndef sbRECEIVE_COMPLETED
#define sbRECEIVE_COMPLETED( pxStreamBuffer ) \
vTaskSuspendAll(); \
{ \
if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL ) \
{ \
( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToSend, \
( uint32_t ) 0, \
eNoAction ); \
( pxStreamBuffer )->xTaskWaitingToSend = NULL; \
} \
} \
( void ) xTaskResumeAll();
#endif /* sbRECEIVE_COMPLETED */
#ifndef sbRECEIVE_COMPLETED_FROM_ISR
#define sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, \
pxHigherPriorityTaskWoken ) \
{ \
UBaseType_t uxSavedInterruptStatus; \
\
uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR(); \
{ \
if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL ) \
{ \
( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend, \
( uint32_t ) 0, \
eNoAction, \
pxHigherPriorityTaskWoken ); \
( pxStreamBuffer )->xTaskWaitingToSend = NULL; \
} \
} \
portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus ); \
}
#endif /* sbRECEIVE_COMPLETED_FROM_ISR */
/* If the user has not provided an application specific Tx notification macro,
* or #defined the notification macro away, them provide a default implementation
* that uses task notifications. */
#ifndef sbSEND_COMPLETED
#define sbSEND_COMPLETED( pxStreamBuffer ) \
vTaskSuspendAll(); \
{ \
if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL ) \
{ \
( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToReceive, \
( uint32_t ) 0, \
eNoAction ); \
( pxStreamBuffer )->xTaskWaitingToReceive = NULL; \
} \
} \
( void ) xTaskResumeAll();
#endif /* sbSEND_COMPLETED */
#ifndef sbSEND_COMPLETE_FROM_ISR
#define sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken ) \
{ \
UBaseType_t uxSavedInterruptStatus; \
\
uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR(); \
{ \
if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL ) \
{ \
( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive, \
( uint32_t ) 0, \
eNoAction, \
pxHigherPriorityTaskWoken ); \
( pxStreamBuffer )->xTaskWaitingToReceive = NULL; \
} \
} \
portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus ); \
}
#endif /* sbSEND_COMPLETE_FROM_ISR */
/*lint -restore (9026) */
/* The number of bytes used to hold the length of a message in the buffer. */
#define sbBYTES_TO_STORE_MESSAGE_LENGTH ( sizeof( configMESSAGE_BUFFER_LENGTH_TYPE ) )
/* Bits stored in the ucFlags field of the stream buffer. */
#define sbFLAGS_IS_MESSAGE_BUFFER ( ( uint8_t ) 1 ) /* Set if the stream buffer was created as a message buffer, in which case it holds discrete messages rather than a stream. */
#define sbFLAGS_IS_STATICALLY_ALLOCATED ( ( uint8_t ) 2 ) /* Set if the stream buffer was created using statically allocated memory. */
/*-----------------------------------------------------------*/
/* Structure that hold state information on the buffer. */
typedef struct StreamBufferDef_t /*lint !e9058 Style convention uses tag. */
{
volatile size_t xTail; /* Index to the next item to read within the buffer. */
volatile size_t xHead; /* Index to the next item to write within the buffer. */
size_t xLength; /* The length of the buffer pointed to by pucBuffer. */
size_t xTriggerLevelBytes; /* The number of bytes that must be in the stream buffer before a task that is waiting for data is unblocked. */
volatile TaskHandle_t xTaskWaitingToReceive; /* Holds the handle of a task waiting for data, or NULL if no tasks are waiting. */
volatile TaskHandle_t xTaskWaitingToSend; /* Holds the handle of a task waiting to send data to a message buffer that is full. */
uint8_t * pucBuffer; /* Points to the buffer itself - that is - the RAM that stores the data passed through the buffer. */
uint8_t ucFlags;
#if ( configUSE_TRACE_FACILITY == 1 )
UBaseType_t uxStreamBufferNumber; /* Used for tracing purposes. */
#endif
} StreamBuffer_t;
/*
* The number of bytes available to be read from the buffer.
*/
static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer ) PRIVILEGED_FUNCTION;
/*
* Add xCount bytes from pucData into the pxStreamBuffer message buffer.
* Returns the number of bytes written, which will either equal xCount in the
* success case, or 0 if there was not enough space in the buffer (in which case
* no data is written into the buffer).
*/
static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
const uint8_t * pucData,
size_t xCount ) PRIVILEGED_FUNCTION;
/*
* If the stream buffer is being used as a message buffer, then reads an entire
* message out of the buffer. If the stream buffer is being used as a stream
* buffer then read as many bytes as possible from the buffer.
* prvReadBytesFromBuffer() is called to actually extract the bytes from the
* buffer's data storage area.
*/
static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
void * pvRxData,
size_t xBufferLengthBytes,
size_t xBytesAvailable,
size_t xBytesToStoreMessageLength ) PRIVILEGED_FUNCTION;
/*
* If the stream buffer is being used as a message buffer, then writes an entire
* message to the buffer. If the stream buffer is being used as a stream
* buffer then write as many bytes as possible to the buffer.
* prvWriteBytestoBuffer() is called to actually send the bytes to the buffer's
* data storage area.
*/
static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
const void * pvTxData,
size_t xDataLengthBytes,
size_t xSpace,
size_t xRequiredSpace ) PRIVILEGED_FUNCTION;
/*
* Read xMaxCount bytes from the pxStreamBuffer message buffer and write them
* to pucData.
*/
static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
uint8_t * pucData,
size_t xMaxCount,
size_t xBytesAvailable ) PRIVILEGED_FUNCTION;
/*
* Called by both pxStreamBufferCreate() and pxStreamBufferCreateStatic() to
* initialise the members of the newly created stream buffer structure.
*/
static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
uint8_t * const pucBuffer,
size_t xBufferSizeBytes,
size_t xTriggerLevelBytes,
uint8_t ucFlags ) PRIVILEGED_FUNCTION;
/*-----------------------------------------------------------*/
#if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
StreamBufferHandle_t xStreamBufferGenericCreate( size_t xBufferSizeBytes,
size_t xTriggerLevelBytes,
BaseType_t xIsMessageBuffer )
{
uint8_t * pucAllocatedMemory;
uint8_t ucFlags;
/* In case the stream buffer is going to be used as a message buffer
* (that is, it will hold discrete messages with a little meta data that
* says how big the next message is) check the buffer will be large enough
* to hold at least one message. */
if( xIsMessageBuffer == pdTRUE )
{
/* Is a message buffer but not statically allocated. */
ucFlags = sbFLAGS_IS_MESSAGE_BUFFER;
configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
}
else
{
/* Not a message buffer and not statically allocated. */
ucFlags = 0;
configASSERT( xBufferSizeBytes > 0 );
}
configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
/* A trigger level of 0 would cause a waiting task to unblock even when
* the buffer was empty. */
if( xTriggerLevelBytes == ( size_t ) 0 )
{
xTriggerLevelBytes = ( size_t ) 1;
}
/* A stream buffer requires a StreamBuffer_t structure and a buffer.
* Both are allocated in a single call to pvPortMalloc(). The
* StreamBuffer_t structure is placed at the start of the allocated memory
* and the buffer follows immediately after. The requested size is
* incremented so the free space is returned as the user would expect -
* this is a quirk of the implementation that means otherwise the free
* space would be reported as one byte smaller than would be logically
* expected. */
xBufferSizeBytes++;
pucAllocatedMemory = ( uint8_t * ) pvPortMalloc( xBufferSizeBytes + sizeof( StreamBuffer_t ) ); /*lint !e9079 malloc() only returns void*. */
if( pucAllocatedMemory != NULL )
{
prvInitialiseNewStreamBuffer( ( StreamBuffer_t * ) pucAllocatedMemory, /* Structure at the start of the allocated memory. */ /*lint !e9087 Safe cast as allocated memory is aligned. */ /*lint !e826 Area is not too small and alignment is guaranteed provided malloc() behaves as expected and returns aligned buffer. */
pucAllocatedMemory + sizeof( StreamBuffer_t ), /* Storage area follows. */ /*lint !e9016 Indexing past structure valid for uint8_t pointer, also storage area has no alignment requirement. */
xBufferSizeBytes,
xTriggerLevelBytes,
ucFlags );
traceSTREAM_BUFFER_CREATE( ( ( StreamBuffer_t * ) pucAllocatedMemory ), xIsMessageBuffer );
}
else
{
traceSTREAM_BUFFER_CREATE_FAILED( xIsMessageBuffer );
}
return ( StreamBufferHandle_t ) pucAllocatedMemory; /*lint !e9087 !e826 Safe cast as allocated memory is aligned. */
}
#endif /* configSUPPORT_DYNAMIC_ALLOCATION */
/*-----------------------------------------------------------*/
#if ( configSUPPORT_STATIC_ALLOCATION == 1 )
StreamBufferHandle_t xStreamBufferGenericCreateStatic( size_t xBufferSizeBytes,
size_t xTriggerLevelBytes,
BaseType_t xIsMessageBuffer,
uint8_t * const pucStreamBufferStorageArea,
StaticStreamBuffer_t * const pxStaticStreamBuffer )
{
StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer; /*lint !e740 !e9087 Safe cast as StaticStreamBuffer_t is opaque Streambuffer_t. */
StreamBufferHandle_t xReturn;
uint8_t ucFlags;
configASSERT( pucStreamBufferStorageArea );
configASSERT( pxStaticStreamBuffer );
configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
/* A trigger level of 0 would cause a waiting task to unblock even when
* the buffer was empty. */
if( xTriggerLevelBytes == ( size_t ) 0 )
{
xTriggerLevelBytes = ( size_t ) 1;
}
if( xIsMessageBuffer != pdFALSE )
{
/* Statically allocated message buffer. */
ucFlags = sbFLAGS_IS_MESSAGE_BUFFER | sbFLAGS_IS_STATICALLY_ALLOCATED;
}
else
{
/* Statically allocated stream buffer. */
ucFlags = sbFLAGS_IS_STATICALLY_ALLOCATED;
}
/* In case the stream buffer is going to be used as a message buffer
* (that is, it will hold discrete messages with a little meta data that
* says how big the next message is) check the buffer will be large enough
* to hold at least one message. */
configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
#if ( configASSERT_DEFINED == 1 )
{
/* Sanity check that the size of the structure used to declare a
* variable of type StaticStreamBuffer_t equals the size of the real
* message buffer structure. */
volatile size_t xSize = sizeof( StaticStreamBuffer_t );
configASSERT( xSize == sizeof( StreamBuffer_t ) );
} /*lint !e529 xSize is referenced is configASSERT() is defined. */
#endif /* configASSERT_DEFINED */
if( ( pucStreamBufferStorageArea != NULL ) && ( pxStaticStreamBuffer != NULL ) )
{
prvInitialiseNewStreamBuffer( pxStreamBuffer,
pucStreamBufferStorageArea,
xBufferSizeBytes,
xTriggerLevelBytes,
ucFlags );
/* Remember this was statically allocated in case it is ever deleted
* again. */
pxStreamBuffer->ucFlags |= sbFLAGS_IS_STATICALLY_ALLOCATED;
traceSTREAM_BUFFER_CREATE( pxStreamBuffer, xIsMessageBuffer );
xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer; /*lint !e9087 Data hiding requires cast to opaque type. */
}
else
{
xReturn = NULL;
traceSTREAM_BUFFER_CREATE_STATIC_FAILED( xReturn, xIsMessageBuffer );
}
return xReturn;
}
#endif /* ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
/*-----------------------------------------------------------*/
void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer )
{
StreamBuffer_t * pxStreamBuffer = xStreamBuffer;
configASSERT( pxStreamBuffer );
traceSTREAM_BUFFER_DELETE( xStreamBuffer );
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) == ( uint8_t ) pdFALSE )
{
#if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
{
/* Both the structure and the buffer were allocated using a single call
* to pvPortMalloc(), hence only one call to vPortFree() is required. */
vPortFree( ( void * ) pxStreamBuffer ); /*lint !e9087 Standard free() semantics require void *, plus pxStreamBuffer was allocated by pvPortMalloc(). */
}
#else
{
/* Should not be possible to get here, ucFlags must be corrupt.
* Force an assert. */
configASSERT( xStreamBuffer == ( StreamBufferHandle_t ) ~0 );
}
#endif
}
else
{
/* The structure and buffer were not allocated dynamically and cannot be
* freed - just scrub the structure so future use will assert. */
( void ) memset( pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) );
}
}
/*-----------------------------------------------------------*/
BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
BaseType_t xReturn = pdFAIL;
#if ( configUSE_TRACE_FACILITY == 1 )
UBaseType_t uxStreamBufferNumber;
#endif
configASSERT( pxStreamBuffer );
#if ( configUSE_TRACE_FACILITY == 1 )
{
/* Store the stream buffer number so it can be restored after the
* reset. */
uxStreamBufferNumber = pxStreamBuffer->uxStreamBufferNumber;
}
#endif
/* Can only reset a message buffer if there are no tasks blocked on it. */
taskENTER_CRITICAL();
{
if( pxStreamBuffer->xTaskWaitingToReceive == NULL )
{
if( pxStreamBuffer->xTaskWaitingToSend == NULL )
{
prvInitialiseNewStreamBuffer( pxStreamBuffer,
pxStreamBuffer->pucBuffer,
pxStreamBuffer->xLength,
pxStreamBuffer->xTriggerLevelBytes,
pxStreamBuffer->ucFlags );
xReturn = pdPASS;
#if ( configUSE_TRACE_FACILITY == 1 )
{
pxStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
}
#endif
traceSTREAM_BUFFER_RESET( xStreamBuffer );
}
}
}
taskEXIT_CRITICAL();
return xReturn;
}
/*-----------------------------------------------------------*/
BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer,
size_t xTriggerLevel )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
BaseType_t xReturn;
configASSERT( pxStreamBuffer );
/* It is not valid for the trigger level to be 0. */
if( xTriggerLevel == ( size_t ) 0 )
{
xTriggerLevel = ( size_t ) 1;
}
/* The trigger level is the number of bytes that must be in the stream
* buffer before a task that is waiting for data is unblocked. */
if( xTriggerLevel <= pxStreamBuffer->xLength )
{
pxStreamBuffer->xTriggerLevelBytes = xTriggerLevel;
xReturn = pdPASS;
}
else
{
xReturn = pdFALSE;
}
return xReturn;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer )
{
const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xSpace;
configASSERT( pxStreamBuffer );
xSpace = pxStreamBuffer->xLength + pxStreamBuffer->xTail;
xSpace -= pxStreamBuffer->xHead;
xSpace -= ( size_t ) 1;
if( xSpace >= pxStreamBuffer->xLength )
{
xSpace -= pxStreamBuffer->xLength;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
return xSpace;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer )
{
const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReturn;
configASSERT( pxStreamBuffer );
xReturn = prvBytesInBuffer( pxStreamBuffer );
return xReturn;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
const void * pvTxData,
size_t xDataLengthBytes,
TickType_t xTicksToWait )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReturn, xSpace = 0;
size_t xRequiredSpace = xDataLengthBytes;
TimeOut_t xTimeOut;
/* Having a 'isFeasible' variable allows to respect the convention that there is only a return statement at the end. Othewise, return
* could be done as soon as we realise the send cannot happen. We will let the call to 'prvWriteMessageToBuffer' dealing with this scenario. */
BaseType_t xIsFeasible;
configASSERT( pvTxData );
configASSERT( pxStreamBuffer );
/* This send function is used to write to both message buffers and stream
* buffers. If this is a message buffer then the space needed must be
* increased by the amount of bytes needed to store the length of the
* message. */
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
{
xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
/* Overflow? */
configASSERT( xRequiredSpace > xDataLengthBytes );
/* In the case of the message buffer, one has to be able to write the complete message as opposed to
* a stream buffer for semantic reasons. Check if it is physically possible to write the message given
* the length of the buffer. */
if( xRequiredSpace > pxStreamBuffer->xLength )
{
/* The message could never be written because it is greater than the buffer length.
* By setting xIsFeasable to FALSE, we skip over the following do..while loop, thus avoiding
* a deadlock. The call to 'prvWriteMessageToBuffer' toward the end of this function with
* xRequiredSpace greater than xSpace will suffice in not writing anything to the internal buffer.
* Now, the function will return 0 because the message could not be written. Should an error code be
* returned instead ??? In my opinion, probably.. But the return type doesn't allow for negative
* values to be returned. A confusion could exist to the caller. Returning 0 because a timeout occurred
* and a subsequent send attempts could eventually succeed, and returning 0 because a write could never
* happen because of the size are two scenarios to me :/ */
xIsFeasible = pdFALSE;
}
else
{
/* It is possible to write the message completely in the buffer. This is the intended route.
* Let's continue with the regular timeout logic. */
xIsFeasible = pdTRUE;
}
}
else
{
/* In the case of the stream buffer, not being able to completely write the message in the buffer
* is an acceptable scenario, but it has to be dealt with properly */
if( xRequiredSpace > pxStreamBuffer->xLength )
{
/* Not enough buffer space. We will attempt to write as much as we can in this run
* so that the caller can send the remaining in subsequent calls. We avoid a deadlock by
* offering the possibility to take the 'else' branch in the 'if( xSpace < xRequiredSpace )'
* condition inside the following do..while loop */
xRequiredSpace = pxStreamBuffer->xLength;
/* TODO FIXME: Is there a check we should do with the xTriggerLevelBytes value ? */
/* With the adjustment to 'xRequiredSpace', the deadlock is avoided, thus it's now feasible. */
xIsFeasible = pdTRUE;
}
else
{
/* It is possible to write the message completely in the buffer. */
xIsFeasible = pdTRUE;
}
}
/* Added check against xIsFeasible. If it's not feasible, don't even wait for notification, let the call to 'prvWriteMessageToBuffer' do nothing and return 0 */
if( ( xTicksToWait != ( TickType_t ) 0 ) && ( xIsFeasible == pdTRUE ) )
{
vTaskSetTimeOutState( &xTimeOut );
do
{
/* Wait until the required number of bytes are free in the message
* buffer. */
taskENTER_CRITICAL();
{
xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
if( xSpace < xRequiredSpace )
{
/* Clear notification state as going to wait for space. */
( void ) xTaskNotifyStateClear( NULL );
/* Should only be one writer. */
configASSERT( pxStreamBuffer->xTaskWaitingToSend == NULL );
pxStreamBuffer->xTaskWaitingToSend = xTaskGetCurrentTaskHandle();
}
else
{
taskEXIT_CRITICAL();
break;
}
}
taskEXIT_CRITICAL();
traceBLOCKING_ON_STREAM_BUFFER_SEND( xStreamBuffer );
( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
pxStreamBuffer->xTaskWaitingToSend = NULL;
} while( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
if( xSpace == ( size_t ) 0 )
{
xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
if( xReturn > ( size_t ) 0 )
{
traceSTREAM_BUFFER_SEND( xStreamBuffer, xReturn );
/* Was a task waiting for the data? */
if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
{
sbSEND_COMPLETED( pxStreamBuffer );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
traceSTREAM_BUFFER_SEND_FAILED( xStreamBuffer );
}
return xReturn;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
const void * pvTxData,
size_t xDataLengthBytes,
BaseType_t * const pxHigherPriorityTaskWoken )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReturn, xSpace;
size_t xRequiredSpace = xDataLengthBytes;
configASSERT( pvTxData );
configASSERT( pxStreamBuffer );
/* This send function is used to write to both message buffers and stream
* buffers. If this is a message buffer then the space needed must be
* increased by the amount of bytes needed to store the length of the
* message. */
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
{
xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
}
else
{
mtCOVERAGE_TEST_MARKER();
}
xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
if( xReturn > ( size_t ) 0 )
{
/* Was a task waiting for the data? */
if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
{
sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
traceSTREAM_BUFFER_SEND_FROM_ISR( xStreamBuffer, xReturn );
return xReturn;
}
/*-----------------------------------------------------------*/
static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
const void * pvTxData,
size_t xDataLengthBytes,
size_t xSpace,
size_t xRequiredSpace )
{
BaseType_t xShouldWrite;
size_t xReturn;
if( xSpace == ( size_t ) 0 )
{
/* Doesn't matter if this is a stream buffer or a message buffer, there
* is no space to write. */
xShouldWrite = pdFALSE;
}
else if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) == ( uint8_t ) 0 )
{
/* This is a stream buffer, as opposed to a message buffer, so writing a
* stream of bytes rather than discrete messages. Write as many bytes as
* possible. */
xShouldWrite = pdTRUE;
xDataLengthBytes = configMIN( xDataLengthBytes, xSpace );
}
else if( xSpace >= xRequiredSpace )
{
/* This is a message buffer, as opposed to a stream buffer, and there
* is enough space to write both the message length and the message itself
* into the buffer. Start by writing the length of the data, the data
* itself will be written later in this function. */
xShouldWrite = pdTRUE;
( void ) prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) &( xDataLengthBytes ), sbBYTES_TO_STORE_MESSAGE_LENGTH );
}
else
{
/* There is space available, but not enough space. */
xShouldWrite = pdFALSE;
}
if( xShouldWrite != pdFALSE )
{
/* Writes the data itself. */
xReturn = prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) pvTxData, xDataLengthBytes ); /*lint !e9079 Storage buffer is implemented as uint8_t for ease of sizing, alighment and access. */
}
else
{
xReturn = 0;
}
return xReturn;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
void * pvRxData,
size_t xBufferLengthBytes,
TickType_t xTicksToWait )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
configASSERT( pvRxData );
configASSERT( pxStreamBuffer );
/* This receive function is used by both message buffers, which store
* discrete messages, and stream buffers, which store a continuous stream of
* bytes. Discrete messages include an additional
* sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
* message. */
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
{
xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
}
else
{
xBytesToStoreMessageLength = 0;
}
if( xTicksToWait != ( TickType_t ) 0 )
{
/* Checking if there is data and clearing the notification state must be
* performed atomically. */
taskENTER_CRITICAL();
{
xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
/* If this function was invoked by a message buffer read then
* xBytesToStoreMessageLength holds the number of bytes used to hold
* the length of the next discrete message. If this function was
* invoked by a stream buffer read then xBytesToStoreMessageLength will
* be 0. */
if( xBytesAvailable <= xBytesToStoreMessageLength )
{
/* Clear notification state as going to wait for data. */
( void ) xTaskNotifyStateClear( NULL );
/* Should only be one reader. */
configASSERT( pxStreamBuffer->xTaskWaitingToReceive == NULL );
pxStreamBuffer->xTaskWaitingToReceive = xTaskGetCurrentTaskHandle();
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
taskEXIT_CRITICAL();
if( xBytesAvailable <= xBytesToStoreMessageLength )
{
/* Wait for data to be available. */
traceBLOCKING_ON_STREAM_BUFFER_RECEIVE( xStreamBuffer );
( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
pxStreamBuffer->xTaskWaitingToReceive = NULL;
/* Recheck the data available after blocking. */
xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
}
/* Whether receiving a discrete message (where xBytesToStoreMessageLength
* holds the number of bytes used to store the message length) or a stream of
* bytes (where xBytesToStoreMessageLength is zero), the number of bytes
* available must be greater than xBytesToStoreMessageLength to be able to
* read bytes from the buffer. */
if( xBytesAvailable > xBytesToStoreMessageLength )
{
xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable, xBytesToStoreMessageLength );
/* Was a task waiting for space in the buffer? */
if( xReceivedLength != ( size_t ) 0 )
{
traceSTREAM_BUFFER_RECEIVE( xStreamBuffer, xReceivedLength );
sbRECEIVE_COMPLETED( pxStreamBuffer );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
traceSTREAM_BUFFER_RECEIVE_FAILED( xStreamBuffer );
mtCOVERAGE_TEST_MARKER();
}
return xReceivedLength;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferNextMessageLengthBytes( StreamBufferHandle_t xStreamBuffer )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReturn, xBytesAvailable, xOriginalTail;
configMESSAGE_BUFFER_LENGTH_TYPE xTempReturn;
configASSERT( pxStreamBuffer );
/* Ensure the stream buffer is being used as a message buffer. */
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
{
xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
if( xBytesAvailable > sbBYTES_TO_STORE_MESSAGE_LENGTH )
{
/* The number of bytes available is greater than the number of bytes
* required to hold the length of the next message, so another message
* is available. Return its length without removing the length bytes
* from the buffer. A copy of the tail is stored so the buffer can be
* returned to its prior state as the message is not actually being
* removed from the buffer. */
xOriginalTail = pxStreamBuffer->xTail;
( void ) prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempReturn, sbBYTES_TO_STORE_MESSAGE_LENGTH, xBytesAvailable );
xReturn = ( size_t ) xTempReturn;
pxStreamBuffer->xTail = xOriginalTail;
}
else
{
/* The minimum amount of bytes in a message buffer is
* ( sbBYTES_TO_STORE_MESSAGE_LENGTH + 1 ), so if xBytesAvailable is
* less than sbBYTES_TO_STORE_MESSAGE_LENGTH the only other valid
* value is 0. */
configASSERT( xBytesAvailable == 0 );
xReturn = 0;
}
}
else
{
xReturn = 0;
}
return xReturn;
}
/*-----------------------------------------------------------*/
size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
void * pvRxData,
size_t xBufferLengthBytes,
BaseType_t * const pxHigherPriorityTaskWoken )
{
StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
configASSERT( pvRxData );
configASSERT( pxStreamBuffer );
/* This receive function is used by both message buffers, which store
* discrete messages, and stream buffers, which store a continuous stream of
* bytes. Discrete messages include an additional
* sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
* message. */
if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
{
xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
}
else
{
xBytesToStoreMessageLength = 0;
}
xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
/* Whether receiving a discrete message (where xBytesToStoreMessageLength
* holds the number of bytes used to store the message length) or a stream of
* bytes (where xBytesToStoreMessageLength is zero), the number of bytes
* available must be greater than xBytesToStoreMessageLength to be able to
* read bytes from the buffer. */
if( xBytesAvailable > xBytesToStoreMessageLength )
{
xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable, xBytesToStoreMessageLength );
/* Was a task waiting for space in the buffer? */
if( xReceivedLength != ( size_t ) 0 )
{
sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
}
else
{
mtCOVERAGE_TEST_MARKER();
}
}
else
{
mtCOVERAGE_TEST_MARKER();
}
traceSTREAM_BUFFER_RECEIVE_FROM_ISR( xStreamBuffer, xReceivedLength );
return xReceivedLength;
}
/*-----------------------------------------------------------*/
static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
void * pvRxData,
size_t xBufferLengthBytes,
size_t xBytesAvailable,
size_t xBytesToStoreMessageLength )
{
size_t xOriginalTail, xReceivedLength, xNextMessageLength;
configMESSAGE_BUFFER_LENGTH_TYPE xTempNextMessageLength;
if( xBytesToStoreMessageLength != ( size_t ) 0 )
{
/* A discrete message is being received. First receive the length
* of the message. A copy of the tail is stored so the buffer can be
* returned to its prior state if the length of the message is too
* large for the provided buffer. */
xOriginalTail = pxStreamBuffer->xTail;
( void ) prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempNextMessageLength, xBytesToStoreMessageLength, xBytesAvailable );
xNextMessageLength = ( size_t ) xTempNextMessageLength;
/* Reduce the number of bytes available by the number of bytes just
* read out. */
xBytesAvailable -= xBytesToStoreMessageLength;
/* Check there is enough space in the buffer provided by the
* user. */
if( xNextMessageLength > xBufferLengthBytes )
{
/* The user has provided insufficient space to read the message
* so return the buffer to its previous state (so the length of
* the message is in the buffer again). */
pxStreamBuffer->xTail = xOriginalTail;