begriffs open source - freertos/blob - stream_buffer.c

   1 /*
   2  * FreeRTOS Kernel V10.4.3
   3  * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   6  * this software and associated documentation files (the "Software"), to deal in
   7  * the Software without restriction, including without limitation the rights to
   8  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
   9  * the Software, and to permit persons to whom the Software is furnished to do so,
  10  * subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in all
  13  * copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  17  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  18  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  19  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  20  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  * https://www.FreeRTOS.org
  23  * https://github.com/FreeRTOS
  24  *
  25  */
  26
  27 /* Standard includes. */
  28 #include <stdint.h>
  29 #include <string.h>
  30
  31 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
  32  * all the API functions to use the MPU wrappers.  That should only be done when
  33  * task.h is included from an application file. */
  34 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  35
  36 /* FreeRTOS includes. */
  37 #include "FreeRTOS.h"
  38 #include "task.h"
  39 #include "stream_buffer.h"
  40
  41 #if ( configUSE_TASK_NOTIFICATIONS != 1 )
  42     #error configUSE_TASK_NOTIFICATIONS must be set to 1 to build stream_buffer.c
  43 #endif
  44
  45 /* Lint e961, e9021 and e750 are suppressed as a MISRA exception justified
  46  * because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
  47  * for the header files above, but not in this file, in order to generate the
  48  * correct privileged Vs unprivileged linkage and placement. */
  49 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750 !e9021. */
  50
  51 /* If the user has not provided application specific Rx notification macros,
  52  * or #defined the notification macros away, then provide default implementations
  53  * that uses task notifications. */
  54 /*lint -save -e9026 Function like macros allowed and needed here so they can be overridden. */
  55 #ifndef sbRECEIVE_COMPLETED
  56     #define sbRECEIVE_COMPLETED( pxStreamBuffer )                         \
  57     vTaskSuspendAll();                                                    \
  58     {                                                                     \
  59         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )              \
  60         {                                                                 \
  61             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToSend, \
  62                                   ( uint32_t ) 0,                         \
  63                                   eNoAction );                            \
  64             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                \
  65         }                                                                 \
  66     }                                                                     \
  67     ( void ) xTaskResumeAll();
  68 #endif /* sbRECEIVE_COMPLETED */
  69
  70 #ifndef sbRECEIVE_COMPLETED_FROM_ISR
  71     #define sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer,                            \
  72                                           pxHigherPriorityTaskWoken )                \
  73     {                                                                                \
  74         UBaseType_t uxSavedInterruptStatus;                                          \
  75                                                                                      \
  76         uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR();  \
  77         {                                                                            \
  78             if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )                     \
  79             {                                                                        \
  80                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend, \
  81                                              ( uint32_t ) 0,                         \
  82                                              eNoAction,                              \
  83                                              pxHigherPriorityTaskWoken );            \
  84                 ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                       \
  85             }                                                                        \
  86         }                                                                            \
  87         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );                 \
  88     }
  89 #endif /* sbRECEIVE_COMPLETED_FROM_ISR */
  90
  91 /* If the user has not provided an application specific Tx notification macro,
  92  * or #defined the notification macro away, them provide a default implementation
  93  * that uses task notifications. */
  94 #ifndef sbSEND_COMPLETED
  95     #define sbSEND_COMPLETED( pxStreamBuffer )                               \
  96     vTaskSuspendAll();                                                       \
  97     {                                                                        \
  98         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )              \
  99         {                                                                    \
 100             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 101                                   ( uint32_t ) 0,                            \
 102                                   eNoAction );                               \
 103             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                \
 104         }                                                                    \
 105     }                                                                        \
 106     ( void ) xTaskResumeAll();
 107 #endif /* sbSEND_COMPLETED */
 108
 109 #ifndef sbSEND_COMPLETE_FROM_ISR
 110     #define sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken )       \
 111     {                                                                                   \
 112         UBaseType_t uxSavedInterruptStatus;                                             \
 113                                                                                         \
 114         uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR();     \
 115         {                                                                               \
 116             if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )                     \
 117             {                                                                           \
 118                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 119                                              ( uint32_t ) 0,                            \
 120                                              eNoAction,                                 \
 121                                              pxHigherPriorityTaskWoken );               \
 122                 ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                       \
 123             }                                                                           \
 124         }                                                                               \
 125         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );                    \
 126     }
 127 #endif /* sbSEND_COMPLETE_FROM_ISR */
 128 /*lint -restore (9026) */
 129
 130 /* The number of bytes used to hold the length of a message in the buffer. */
 131 #define sbBYTES_TO_STORE_MESSAGE_LENGTH    ( sizeof( configMESSAGE_BUFFER_LENGTH_TYPE ) )
 132
 133 /* Bits stored in the ucFlags field of the stream buffer. */
 134 #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. */
 135 #define sbFLAGS_IS_STATICALLY_ALLOCATED    ( ( uint8_t ) 2 ) /* Set if the stream buffer was created using statically allocated memory. */
 136
 137 /*-----------------------------------------------------------*/
 138
 139 /* Structure that hold state information on the buffer. */
 140 typedef struct StreamBufferDef_t                 /*lint !e9058 Style convention uses tag. */
 141 {
 142     volatile size_t xTail;                       /* Index to the next item to read within the buffer. */
 143     volatile size_t xHead;                       /* Index to the next item to write within the buffer. */
 144     size_t xLength;                              /* The length of the buffer pointed to by pucBuffer. */
 145     size_t xTriggerLevelBytes;                   /* The number of bytes that must be in the stream buffer before a task that is waiting for data is unblocked. */
 146     volatile TaskHandle_t xTaskWaitingToReceive; /* Holds the handle of a task waiting for data, or NULL if no tasks are waiting. */
 147     volatile TaskHandle_t xTaskWaitingToSend;    /* Holds the handle of a task waiting to send data to a message buffer that is full. */
 148     uint8_t * pucBuffer;                         /* Points to the buffer itself - that is - the RAM that stores the data passed through the buffer. */
 149     uint8_t ucFlags;
 150
 151     #if ( configUSE_TRACE_FACILITY == 1 )
 152         UBaseType_t uxStreamBufferNumber; /* Used for tracing purposes. */
 153     #endif
 154 } StreamBuffer_t;
 155
 156 /*
 157  * The number of bytes available to be read from the buffer.
 158  */
 159 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer ) PRIVILEGED_FUNCTION;
 160
 161 /*
 162  * Add xCount bytes from pucData into the pxStreamBuffer's data storage area.
 163  * This function does not update the buffer's xHead pointer, so multiple writes
 164  * may be chained together "atomically". This is useful for Message Buffers where
 165  * the length and data bytes are written in two separate chunks, and we don't want
 166  * the reader to see the buffer as having grown until after all data is copied over.
 167  * This function takes a custom xHead value to indicate where to write to (necessary
 168  * for chaining) and returns the the resulting xHead position.
 169  * To mark the write as complete, manually set the buffer's xHead field with the
 170  * returned xHead from this function.
 171  */
 172 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
 173                                      const uint8_t * pucData,
 174                                      size_t xCount,
 175                                      size_t xHead ) PRIVILEGED_FUNCTION;
 176
 177 /*
 178  * If the stream buffer is being used as a message buffer, then reads an entire
 179  * message out of the buffer.  If the stream buffer is being used as a stream
 180  * buffer then read as many bytes as possible from the buffer.
 181  * prvReadBytesFromBuffer() is called to actually extract the bytes from the
 182  * buffer's data storage area.
 183  */
 184 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
 185                                         void * pvRxData,
 186                                         size_t xBufferLengthBytes,
 187                                         size_t xBytesAvailable ) PRIVILEGED_FUNCTION;
 188
 189 /*
 190  * If the stream buffer is being used as a message buffer, then writes an entire
 191  * message to the buffer.  If the stream buffer is being used as a stream
 192  * buffer then write as many bytes as possible to the buffer.
 193  * prvWriteBytestoBuffer() is called to actually send the bytes to the buffer's
 194  * data storage area.
 195  */
 196 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 197                                        const void * pvTxData,
 198                                        size_t xDataLengthBytes,
 199                                        size_t xSpace,
 200                                        size_t xRequiredSpace ) PRIVILEGED_FUNCTION;
 201
 202 /*
 203  * Copies xCount bytes from the pxStreamBuffer's data storage area to pucData.
 204  * This function does not update the buffer's xTail pointer, so multiple reads
 205  * may be chained together "atomically". This is useful for Message Buffers where
 206  * the length and data bytes are read in two separate chunks, and we don't want
 207  * the writer to see the buffer as having more free space until after all data is
 208  * copied over, especially if we have to abort the read due to insufficient receiving space.
 209  * This function takes a custom xTail value to indicate where to read from (necessary
 210  * for chaining) and returns the the resulting xTail position.
 211  * To mark the read as complete, manually set the buffer's xTail field with the
 212  * returned xTail from this function.
 213  */
 214 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
 215                                       uint8_t * pucData,
 216                                       size_t xCount,
 217                                       size_t xTail ) PRIVILEGED_FUNCTION;
 218
 219 /*
 220  * Called by both pxStreamBufferCreate() and pxStreamBufferCreateStatic() to
 221  * initialise the members of the newly created stream buffer structure.
 222  */
 223 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
 224                                           uint8_t * const pucBuffer,
 225                                           size_t xBufferSizeBytes,
 226                                           size_t xTriggerLevelBytes,
 227                                           uint8_t ucFlags ) PRIVILEGED_FUNCTION;
 228
 229 /*-----------------------------------------------------------*/
 230
 231 #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 232
 233     StreamBufferHandle_t xStreamBufferGenericCreate( size_t xBufferSizeBytes,
 234                                                      size_t xTriggerLevelBytes,
 235                                                      BaseType_t xIsMessageBuffer )
 236     {
 237         uint8_t * pucAllocatedMemory;
 238         uint8_t ucFlags;
 239
 240         /* In case the stream buffer is going to be used as a message buffer
 241          * (that is, it will hold discrete messages with a little meta data that
 242          * says how big the next message is) check the buffer will be large enough
 243          * to hold at least one message. */
 244         if( xIsMessageBuffer == pdTRUE )
 245         {
 246             /* Is a message buffer but not statically allocated. */
 247             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER;
 248             configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 249         }
 250         else
 251         {
 252             /* Not a message buffer and not statically allocated. */
 253             ucFlags = 0;
 254             configASSERT( xBufferSizeBytes > 0 );
 255         }
 256
 257         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 258
 259         /* A trigger level of 0 would cause a waiting task to unblock even when
 260          * the buffer was empty. */
 261         if( xTriggerLevelBytes == ( size_t ) 0 )
 262         {
 263             xTriggerLevelBytes = ( size_t ) 1;
 264         }
 265
 266         /* A stream buffer requires a StreamBuffer_t structure and a buffer.
 267          * Both are allocated in a single call to pvPortMalloc().  The
 268          * StreamBuffer_t structure is placed at the start of the allocated memory
 269          * and the buffer follows immediately after.  The requested size is
 270          * incremented so the free space is returned as the user would expect -
 271          * this is a quirk of the implementation that means otherwise the free
 272          * space would be reported as one byte smaller than would be logically
 273          * expected. */
 274         if( xBufferSizeBytes < ( xBufferSizeBytes + 1 + sizeof( StreamBuffer_t ) ) )
 275         {
 276             xBufferSizeBytes++;
 277             pucAllocatedMemory = ( uint8_t * ) pvPortMalloc( xBufferSizeBytes + sizeof( StreamBuffer_t ) ); /*lint !e9079 malloc() only returns void*. */
 278         }
 279         else
 280         {
 281             pucAllocatedMemory = NULL;
 282         }
 283
 284         if( pucAllocatedMemory != NULL )
 285         {
 286             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. */
 287                                           pucAllocatedMemory + sizeof( StreamBuffer_t ), /* Storage area follows. */ /*lint !e9016 Indexing past structure valid for uint8_t pointer, also storage area has no alignment requirement. */
 288                                           xBufferSizeBytes,
 289                                           xTriggerLevelBytes,
 290                                           ucFlags );
 291
 292             traceSTREAM_BUFFER_CREATE( ( ( StreamBuffer_t * ) pucAllocatedMemory ), xIsMessageBuffer );
 293         }
 294         else
 295         {
 296             traceSTREAM_BUFFER_CREATE_FAILED( xIsMessageBuffer );
 297         }
 298
 299         return ( StreamBufferHandle_t ) pucAllocatedMemory; /*lint !e9087 !e826 Safe cast as allocated memory is aligned. */
 300     }
 301
 302 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
 303 /*-----------------------------------------------------------*/
 304
 305 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
 306
 307     StreamBufferHandle_t xStreamBufferGenericCreateStatic( size_t xBufferSizeBytes,
 308                                                            size_t xTriggerLevelBytes,
 309                                                            BaseType_t xIsMessageBuffer,
 310                                                            uint8_t * const pucStreamBufferStorageArea,
 311                                                            StaticStreamBuffer_t * const pxStaticStreamBuffer )
 312     {
 313         StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer; /*lint !e740 !e9087 Safe cast as StaticStreamBuffer_t is opaque Streambuffer_t. */
 314         StreamBufferHandle_t xReturn;
 315         uint8_t ucFlags;
 316
 317         configASSERT( pucStreamBufferStorageArea );
 318         configASSERT( pxStaticStreamBuffer );
 319         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 320
 321         /* A trigger level of 0 would cause a waiting task to unblock even when
 322          * the buffer was empty. */
 323         if( xTriggerLevelBytes == ( size_t ) 0 )
 324         {
 325             xTriggerLevelBytes = ( size_t ) 1;
 326         }
 327
 328         if( xIsMessageBuffer != pdFALSE )
 329         {
 330             /* Statically allocated message buffer. */
 331             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER | sbFLAGS_IS_STATICALLY_ALLOCATED;
 332         }
 333         else
 334         {
 335             /* Statically allocated stream buffer. */
 336             ucFlags = sbFLAGS_IS_STATICALLY_ALLOCATED;
 337         }
 338
 339         /* In case the stream buffer is going to be used as a message buffer
 340          * (that is, it will hold discrete messages with a little meta data that
 341          * says how big the next message is) check the buffer will be large enough
 342          * to hold at least one message. */
 343         configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 344
 345         #if ( configASSERT_DEFINED == 1 )
 346             {
 347                 /* Sanity check that the size of the structure used to declare a
 348                  * variable of type StaticStreamBuffer_t equals the size of the real
 349                  * message buffer structure. */
 350                 volatile size_t xSize = sizeof( StaticStreamBuffer_t );
 351                 configASSERT( xSize == sizeof( StreamBuffer_t ) );
 352             } /*lint !e529 xSize is referenced is configASSERT() is defined. */
 353         #endif /* configASSERT_DEFINED */
 354
 355         if( ( pucStreamBufferStorageArea != NULL ) && ( pxStaticStreamBuffer != NULL ) )
 356         {
 357             prvInitialiseNewStreamBuffer( pxStreamBuffer,
 358                                           pucStreamBufferStorageArea,
 359                                           xBufferSizeBytes,
 360                                           xTriggerLevelBytes,
 361                                           ucFlags );
 362
 363             /* Remember this was statically allocated in case it is ever deleted
 364              * again. */
 365             pxStreamBuffer->ucFlags |= sbFLAGS_IS_STATICALLY_ALLOCATED;
 366
 367             traceSTREAM_BUFFER_CREATE( pxStreamBuffer, xIsMessageBuffer );
 368
 369             xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer; /*lint !e9087 Data hiding requires cast to opaque type. */
 370         }
 371         else
 372         {
 373             xReturn = NULL;
 374             traceSTREAM_BUFFER_CREATE_STATIC_FAILED( xReturn, xIsMessageBuffer );
 375         }
 376
 377         return xReturn;
 378     }
 379
 380 #endif /* ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
 381 /*-----------------------------------------------------------*/
 382
 383 void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer )
 384 {
 385     StreamBuffer_t * pxStreamBuffer = xStreamBuffer;
 386
 387     configASSERT( pxStreamBuffer );
 388
 389     traceSTREAM_BUFFER_DELETE( xStreamBuffer );
 390
 391     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) == ( uint8_t ) pdFALSE )
 392     {
 393         #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 394             {
 395                 /* Both the structure and the buffer were allocated using a single call
 396                 * to pvPortMalloc(), hence only one call to vPortFree() is required. */
 397                 vPortFree( ( void * ) pxStreamBuffer ); /*lint !e9087 Standard free() semantics require void *, plus pxStreamBuffer was allocated by pvPortMalloc(). */
 398             }
 399         #else
 400             {
 401                 /* Should not be possible to get here, ucFlags must be corrupt.
 402                  * Force an assert. */
 403                 configASSERT( xStreamBuffer == ( StreamBufferHandle_t ) ~0 );
 404             }
 405         #endif
 406     }
 407     else
 408     {
 409         /* The structure and buffer were not allocated dynamically and cannot be
 410          * freed - just scrub the structure so future use will assert. */
 411         ( void ) memset( pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) );
 412     }
 413 }
 414 /*-----------------------------------------------------------*/
 415
 416 BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer )
 417 {
 418     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 419     BaseType_t xReturn = pdFAIL;
 420
 421     #if ( configUSE_TRACE_FACILITY == 1 )
 422         UBaseType_t uxStreamBufferNumber;
 423     #endif
 424
 425     configASSERT( pxStreamBuffer );
 426
 427     #if ( configUSE_TRACE_FACILITY == 1 )
 428         {
 429             /* Store the stream buffer number so it can be restored after the
 430              * reset. */
 431             uxStreamBufferNumber = pxStreamBuffer->uxStreamBufferNumber;
 432         }
 433     #endif
 434
 435     /* Can only reset a message buffer if there are no tasks blocked on it. */
 436     taskENTER_CRITICAL();
 437     {
 438         if( pxStreamBuffer->xTaskWaitingToReceive == NULL )
 439         {
 440             if( pxStreamBuffer->xTaskWaitingToSend == NULL )
 441             {
 442                 prvInitialiseNewStreamBuffer( pxStreamBuffer,
 443                                               pxStreamBuffer->pucBuffer,
 444                                               pxStreamBuffer->xLength,
 445                                               pxStreamBuffer->xTriggerLevelBytes,
 446                                               pxStreamBuffer->ucFlags );
 447                 xReturn = pdPASS;
 448
 449                 #if ( configUSE_TRACE_FACILITY == 1 )
 450                     {
 451                         pxStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
 452                     }
 453                 #endif
 454
 455                 traceSTREAM_BUFFER_RESET( xStreamBuffer );
 456             }
 457         }
 458     }
 459     taskEXIT_CRITICAL();
 460
 461     return xReturn;
 462 }
 463 /*-----------------------------------------------------------*/
 464
 465 BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer,
 466                                          size_t xTriggerLevel )
 467 {
 468     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 469     BaseType_t xReturn;
 470
 471     configASSERT( pxStreamBuffer );
 472
 473     /* It is not valid for the trigger level to be 0. */
 474     if( xTriggerLevel == ( size_t ) 0 )
 475     {
 476         xTriggerLevel = ( size_t ) 1;
 477     }
 478
 479     /* The trigger level is the number of bytes that must be in the stream
 480      * buffer before a task that is waiting for data is unblocked. */
 481     if( xTriggerLevel < pxStreamBuffer->xLength )
 482     {
 483         pxStreamBuffer->xTriggerLevelBytes = xTriggerLevel;
 484         xReturn = pdPASS;
 485     }
 486     else
 487     {
 488         xReturn = pdFALSE;
 489     }
 490
 491     return xReturn;
 492 }
 493 /*-----------------------------------------------------------*/
 494
 495 size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer )
 496 {
 497     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 498     size_t xSpace;
 499     size_t xOriginalTail;
 500
 501     configASSERT( pxStreamBuffer );
 502
 503     /* The code below reads xTail and then xHead.  This is safe if the stream
 504     buffer is updated once between the two reads - but not if the stream buffer
 505     is updated more than once between the two reads - hence the loop. */
 506     do
 507     {
 508         xOriginalTail = pxStreamBuffer->xTail;
 509         xSpace = pxStreamBuffer->xLength + pxStreamBuffer->xTail;
 510         xSpace -= pxStreamBuffer->xHead;
 511     } while( xOriginalTail != pxStreamBuffer->xTail );
 512     xSpace -= ( size_t ) 1;
 513
 514     if( xSpace >= pxStreamBuffer->xLength )
 515     {
 516         xSpace -= pxStreamBuffer->xLength;
 517     }
 518     else
 519     {
 520         mtCOVERAGE_TEST_MARKER();
 521     }
 522
 523     return xSpace;
 524 }
 525 /*-----------------------------------------------------------*/
 526
 527 size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer )
 528 {
 529     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 530     size_t xReturn;
 531
 532     configASSERT( pxStreamBuffer );
 533
 534     xReturn = prvBytesInBuffer( pxStreamBuffer );
 535     return xReturn;
 536 }
 537 /*-----------------------------------------------------------*/
 538
 539 size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
 540                           const void * pvTxData,
 541                           size_t xDataLengthBytes,
 542                           TickType_t xTicksToWait )
 543 {
 544     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 545     size_t xReturn, xSpace = 0;
 546     size_t xRequiredSpace = xDataLengthBytes;
 547     TimeOut_t xTimeOut;
 548     size_t xMaxReportedSpace = 0;
 549
 550     configASSERT( pvTxData );
 551     configASSERT( pxStreamBuffer );
 552
 553     /* The maximum amount of space a stream buffer will ever report is its length
 554      * minus 1. */
 555     xMaxReportedSpace = pxStreamBuffer->xLength - ( size_t ) 1;
 556
 557     /* This send function is used to write to both message buffers and stream
 558      * buffers.  If this is a message buffer then the space needed must be
 559      * increased by the amount of bytes needed to store the length of the
 560      * message. */
 561     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 562     {
 563         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 564
 565         /* Overflow? */
 566         configASSERT( xRequiredSpace > xDataLengthBytes );
 567
 568         /* If this is a message buffer then it must be possible to write the
 569          * whole message. */
 570         if( xRequiredSpace > xMaxReportedSpace )
 571         {
 572             /* The message would not fit even if the entire buffer was empty,
 573              * so don't wait for space. */
 574             xTicksToWait = ( TickType_t ) 0;
 575         }
 576         else
 577         {
 578             mtCOVERAGE_TEST_MARKER();
 579         }
 580     }
 581     else
 582     {
 583         /* If this is a stream buffer then it is acceptable to write only part
 584          * of the message to the buffer.  Cap the length to the total length of
 585          * the buffer. */
 586         if( xRequiredSpace > xMaxReportedSpace )
 587         {
 588             xRequiredSpace = xMaxReportedSpace;
 589         }
 590         else
 591         {
 592             mtCOVERAGE_TEST_MARKER();
 593         }
 594     }
 595
 596     if( xTicksToWait != ( TickType_t ) 0 )
 597     {
 598         vTaskSetTimeOutState( &xTimeOut );
 599
 600         do
 601         {
 602             /* Wait until the required number of bytes are free in the message
 603              * buffer. */
 604             taskENTER_CRITICAL();
 605             {
 606                 xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 607
 608                 if( xSpace < xRequiredSpace )
 609                 {
 610                     /* Clear notification state as going to wait for space. */
 611                     ( void ) xTaskNotifyStateClear( NULL );
 612
 613                     /* Should only be one writer. */
 614                     configASSERT( pxStreamBuffer->xTaskWaitingToSend == NULL );
 615                     pxStreamBuffer->xTaskWaitingToSend = xTaskGetCurrentTaskHandle();
 616                 }
 617                 else
 618                 {
 619                     taskEXIT_CRITICAL();
 620                     break;
 621                 }
 622             }
 623             taskEXIT_CRITICAL();
 624
 625             traceBLOCKING_ON_STREAM_BUFFER_SEND( xStreamBuffer );
 626             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
 627             pxStreamBuffer->xTaskWaitingToSend = NULL;
 628         } while( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE );
 629     }
 630     else
 631     {
 632         mtCOVERAGE_TEST_MARKER();
 633     }
 634
 635     if( xSpace == ( size_t ) 0 )
 636     {
 637         xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 638     }
 639     else
 640     {
 641         mtCOVERAGE_TEST_MARKER();
 642     }
 643
 644     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 645
 646     if( xReturn > ( size_t ) 0 )
 647     {
 648         traceSTREAM_BUFFER_SEND( xStreamBuffer, xReturn );
 649
 650         /* Was a task waiting for the data? */
 651         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 652         {
 653             sbSEND_COMPLETED( pxStreamBuffer );
 654         }
 655         else
 656         {
 657             mtCOVERAGE_TEST_MARKER();
 658         }
 659     }
 660     else
 661     {
 662         mtCOVERAGE_TEST_MARKER();
 663         traceSTREAM_BUFFER_SEND_FAILED( xStreamBuffer );
 664     }
 665
 666     return xReturn;
 667 }
 668 /*-----------------------------------------------------------*/
 669
 670 size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
 671                                  const void * pvTxData,
 672                                  size_t xDataLengthBytes,
 673                                  BaseType_t * const pxHigherPriorityTaskWoken )
 674 {
 675     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 676     size_t xReturn, xSpace;
 677     size_t xRequiredSpace = xDataLengthBytes;
 678
 679     configASSERT( pvTxData );
 680     configASSERT( pxStreamBuffer );
 681
 682     /* This send function is used to write to both message buffers and stream
 683      * buffers.  If this is a message buffer then the space needed must be
 684      * increased by the amount of bytes needed to store the length of the
 685      * message. */
 686     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 687     {
 688         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 689     }
 690     else
 691     {
 692         mtCOVERAGE_TEST_MARKER();
 693     }
 694
 695     xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 696     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 697
 698     if( xReturn > ( size_t ) 0 )
 699     {
 700         /* Was a task waiting for the data? */
 701         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 702         {
 703             sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
 704         }
 705         else
 706         {
 707             mtCOVERAGE_TEST_MARKER();
 708         }
 709     }
 710     else
 711     {
 712         mtCOVERAGE_TEST_MARKER();
 713     }
 714
 715     traceSTREAM_BUFFER_SEND_FROM_ISR( xStreamBuffer, xReturn );
 716
 717     return xReturn;
 718 }
 719 /*-----------------------------------------------------------*/
 720
 721 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 722                                        const void * pvTxData,
 723                                        size_t xDataLengthBytes,
 724                                        size_t xSpace,
 725                                        size_t xRequiredSpace )
 726 {
 727     size_t xNextHead = pxStreamBuffer->xHead;
 728
 729     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 730     {
 731         /* This is a message buffer, as opposed to a stream buffer. */
 732
 733         if( xSpace >= xRequiredSpace )
 734         {
 735             /* There is enough space to write both the message length and the message
 736              * itself into the buffer.  Start by writing the length of the data, the data
 737              * itself will be written later in this function. */
 738             xNextHead = prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) &( xDataLengthBytes ), sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextHead );
 739         }
 740         else
 741         {
 742             /* Not enough space, so do not write data to the buffer. */
 743             xDataLengthBytes = 0;
 744         }
 745     }
 746     else
 747     {
 748         /* This is a stream buffer, as opposed to a message buffer, so writing a
 749          * stream of bytes rather than discrete messages.  Plan to write as many
 750          * bytes as possible. */
 751         xDataLengthBytes = configMIN( xDataLengthBytes, xSpace );
 752     }
 753
 754     if( xDataLengthBytes != ( size_t ) 0 )
 755     {
 756         /* Write the data to the buffer. */
 757         pxStreamBuffer->xHead = prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) pvTxData, xDataLengthBytes, xNextHead ); /*lint !e9079 Storage buffer is implemented as uint8_t for ease of sizing, alignment and access. */
 758     }
 759
 760     return xDataLengthBytes;
 761 }
 762 /*-----------------------------------------------------------*/
 763
 764 size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
 765                              void * pvRxData,
 766                              size_t xBufferLengthBytes,
 767                              TickType_t xTicksToWait )
 768 {
 769     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 770     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
 771
 772     configASSERT( pvRxData );
 773     configASSERT( pxStreamBuffer );
 774
 775     /* This receive function is used by both message buffers, which store
 776      * discrete messages, and stream buffers, which store a continuous stream of
 777      * bytes.  Discrete messages include an additional
 778      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
 779      * message. */
 780     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 781     {
 782         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
 783     }
 784     else
 785     {
 786         xBytesToStoreMessageLength = 0;
 787     }
 788
 789     if( xTicksToWait != ( TickType_t ) 0 )
 790     {
 791         /* Checking if there is data and clearing the notification state must be
 792          * performed atomically. */
 793         taskENTER_CRITICAL();
 794         {
 795             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 796
 797             /* If this function was invoked by a message buffer read then
 798              * xBytesToStoreMessageLength holds the number of bytes used to hold
 799              * the length of the next discrete message.  If this function was
 800              * invoked by a stream buffer read then xBytesToStoreMessageLength will
 801              * be 0. */
 802             if( xBytesAvailable <= xBytesToStoreMessageLength )
 803             {
 804                 /* Clear notification state as going to wait for data. */
 805                 ( void ) xTaskNotifyStateClear( NULL );
 806
 807                 /* Should only be one reader. */
 808                 configASSERT( pxStreamBuffer->xTaskWaitingToReceive == NULL );
 809                 pxStreamBuffer->xTaskWaitingToReceive = xTaskGetCurrentTaskHandle();
 810             }
 811             else
 812             {
 813                 mtCOVERAGE_TEST_MARKER();
 814             }
 815         }
 816         taskEXIT_CRITICAL();
 817
 818         if( xBytesAvailable <= xBytesToStoreMessageLength )
 819         {
 820             /* Wait for data to be available. */
 821             traceBLOCKING_ON_STREAM_BUFFER_RECEIVE( xStreamBuffer );
 822             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
 823             pxStreamBuffer->xTaskWaitingToReceive = NULL;
 824
 825             /* Recheck the data available after blocking. */
 826             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 827         }
 828         else
 829         {
 830             mtCOVERAGE_TEST_MARKER();
 831         }
 832     }
 833     else
 834     {
 835         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 836     }
 837
 838     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
 839      * holds the number of bytes used to store the message length) or a stream of
 840      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
 841      * available must be greater than xBytesToStoreMessageLength to be able to
 842      * read bytes from the buffer. */
 843     if( xBytesAvailable > xBytesToStoreMessageLength )
 844     {
 845         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
 846
 847         /* Was a task waiting for space in the buffer? */
 848         if( xReceivedLength != ( size_t ) 0 )
 849         {
 850             traceSTREAM_BUFFER_RECEIVE( xStreamBuffer, xReceivedLength );
 851             sbRECEIVE_COMPLETED( pxStreamBuffer );
 852         }
 853         else
 854         {
 855             mtCOVERAGE_TEST_MARKER();
 856         }
 857     }
 858     else
 859     {
 860         traceSTREAM_BUFFER_RECEIVE_FAILED( xStreamBuffer );
 861         mtCOVERAGE_TEST_MARKER();
 862     }
 863
 864     return xReceivedLength;
 865 }
 866 /*-----------------------------------------------------------*/
 867
 868 size_t xStreamBufferNextMessageLengthBytes( StreamBufferHandle_t xStreamBuffer )
 869 {
 870     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 871     size_t xReturn, xBytesAvailable;
 872     configMESSAGE_BUFFER_LENGTH_TYPE xTempReturn;
 873
 874     configASSERT( pxStreamBuffer );
 875
 876     /* Ensure the stream buffer is being used as a message buffer. */
 877     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 878     {
 879         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 880
 881         if( xBytesAvailable > sbBYTES_TO_STORE_MESSAGE_LENGTH )
 882         {
 883             /* The number of bytes available is greater than the number of bytes
 884              * required to hold the length of the next message, so another message
 885              * is available. */
 886              ( void ) prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempReturn, sbBYTES_TO_STORE_MESSAGE_LENGTH, pxStreamBuffer->xTail );
 887              xReturn = ( size_t ) xTempReturn;
 888         }
 889         else
 890         {
 891             /* The minimum amount of bytes in a message buffer is
 892              * ( sbBYTES_TO_STORE_MESSAGE_LENGTH + 1 ), so if xBytesAvailable is
 893              * less than sbBYTES_TO_STORE_MESSAGE_LENGTH the only other valid
 894              * value is 0. */
 895             configASSERT( xBytesAvailable == 0 );
 896             xReturn = 0;
 897         }
 898     }
 899     else
 900     {
 901         xReturn = 0;
 902     }
 903
 904     return xReturn;
 905 }
 906 /*-----------------------------------------------------------*/
 907
 908 size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
 909                                     void * pvRxData,
 910                                     size_t xBufferLengthBytes,
 911                                     BaseType_t * const pxHigherPriorityTaskWoken )
 912 {
 913     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 914     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
 915
 916     configASSERT( pvRxData );
 917     configASSERT( pxStreamBuffer );
 918
 919     /* This receive function is used by both message buffers, which store
 920      * discrete messages, and stream buffers, which store a continuous stream of
 921      * bytes.  Discrete messages include an additional
 922      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
 923      * message. */
 924     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 925     {
 926         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
 927     }
 928     else
 929     {
 930         xBytesToStoreMessageLength = 0;
 931     }
 932
 933     xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 934
 935     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
 936      * holds the number of bytes used to store the message length) or a stream of
 937      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
 938      * available must be greater than xBytesToStoreMessageLength to be able to
 939      * read bytes from the buffer. */
 940     if( xBytesAvailable > xBytesToStoreMessageLength )
 941     {
 942         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
 943
 944         /* Was a task waiting for space in the buffer? */
 945         if( xReceivedLength != ( size_t ) 0 )
 946         {
 947             sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
 948         }
 949         else
 950         {
 951             mtCOVERAGE_TEST_MARKER();
 952         }
 953     }
 954     else
 955     {
 956         mtCOVERAGE_TEST_MARKER();
 957     }
 958
 959     traceSTREAM_BUFFER_RECEIVE_FROM_ISR( xStreamBuffer, xReceivedLength );
 960
 961     return xReceivedLength;
 962 }
 963 /*-----------------------------------------------------------*/
 964
 965 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
 966                                         void * pvRxData,
 967                                         size_t xBufferLengthBytes,
 968                                         size_t xBytesAvailable )
 969 {
 970     size_t xCount, xNextMessageLength;
 971     configMESSAGE_BUFFER_LENGTH_TYPE xTempNextMessageLength;
 972     size_t xNextTail = pxStreamBuffer->xTail;
 973
 974     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 975     {
 976         /* A discrete message is being received.  First receive the length
 977          * of the message. */
 978         xNextTail = prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempNextMessageLength, sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextTail );
 979         xNextMessageLength = ( size_t ) xTempNextMessageLength;
 980
 981         /* Reduce the number of bytes available by the number of bytes just
 982          * read out. */
 983         xBytesAvailable -= sbBYTES_TO_STORE_MESSAGE_LENGTH;
 984
 985         /* Check there is enough space in the buffer provided by the
 986          * user. */
 987         if( xNextMessageLength > xBufferLengthBytes )
 988         {
 989             /* The user has provided insufficient space to read the message. */
 990             xNextMessageLength = 0;
 991         }
 992         else
 993         {
 994             mtCOVERAGE_TEST_MARKER();
 995         }
 996     }
 997     else
 998     {
 999         /* A stream of bytes is being received (as opposed to a discrete
1000          * message), so read as many bytes as possible. */
1001         xNextMessageLength = xBufferLengthBytes;
1002     }
1003
1004     /* Use the minimum of the wanted bytes and the available bytes. */
1005     xCount = configMIN( xNextMessageLength, xBytesAvailable );
1006
1007     if( xCount != ( size_t ) 0 )
1008     {
1009         /* Read the actual data and update the tail to mark the data as officially consumed. */
1010         pxStreamBuffer->xTail = prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) pvRxData, xCount, xNextTail); /*lint !e9079 Data storage area is implemented as uint8_t array for ease of sizing, indexing and alignment. */
1011     }
1012
1013     return xCount;
1014 }
1015 /*-----------------------------------------------------------*/
1016
1017 BaseType_t xStreamBufferIsEmpty( StreamBufferHandle_t xStreamBuffer )
1018 {
1019     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1020     BaseType_t xReturn;
1021     size_t xTail;
1022
1023     configASSERT( pxStreamBuffer );
1024
1025     /* True if no bytes are available. */
1026     xTail = pxStreamBuffer->xTail;
1027
1028     if( pxStreamBuffer->xHead == xTail )
1029     {
1030         xReturn = pdTRUE;
1031     }
1032     else
1033     {
1034         xReturn = pdFALSE;
1035     }
1036
1037     return xReturn;
1038 }
1039 /*-----------------------------------------------------------*/
1040
1041 BaseType_t xStreamBufferIsFull( StreamBufferHandle_t xStreamBuffer )
1042 {
1043     BaseType_t xReturn;
1044     size_t xBytesToStoreMessageLength;
1045     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1046
1047     configASSERT( pxStreamBuffer );
1048
1049     /* This generic version of the receive function is used by both message
1050      * buffers, which store discrete messages, and stream buffers, which store a
1051      * continuous stream of bytes.  Discrete messages include an additional
1052      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the message. */
1053     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1054     {
1055         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
1056     }
1057     else
1058     {
1059         xBytesToStoreMessageLength = 0;
1060     }
1061
1062     /* True if the available space equals zero. */
1063     if( xStreamBufferSpacesAvailable( xStreamBuffer ) <= xBytesToStoreMessageLength )
1064     {
1065         xReturn = pdTRUE;
1066     }
1067     else
1068     {
1069         xReturn = pdFALSE;
1070     }
1071
1072     return xReturn;
1073 }
1074 /*-----------------------------------------------------------*/
1075
1076 BaseType_t xStreamBufferSendCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1077                                               BaseType_t * pxHigherPriorityTaskWoken )
1078 {
1079     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1080     BaseType_t xReturn;
1081     UBaseType_t uxSavedInterruptStatus;
1082
1083     configASSERT( pxStreamBuffer );
1084
1085     uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR();
1086     {
1087         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )
1088         {
1089             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive,
1090                                          ( uint32_t ) 0,
1091                                          eNoAction,
1092                                          pxHigherPriorityTaskWoken );
1093             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;
1094             xReturn = pdTRUE;
1095         }
1096         else
1097         {
1098             xReturn = pdFALSE;
1099         }
1100     }
1101     portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );
1102
1103     return xReturn;
1104 }
1105 /*-----------------------------------------------------------*/
1106
1107 BaseType_t xStreamBufferReceiveCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1108                                                  BaseType_t * pxHigherPriorityTaskWoken )
1109 {
1110     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1111     BaseType_t xReturn;
1112     UBaseType_t uxSavedInterruptStatus;
1113
1114     configASSERT( pxStreamBuffer );
1115
1116     uxSavedInterruptStatus = ( UBaseType_t ) portSET_INTERRUPT_MASK_FROM_ISR();
1117     {
1118         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )
1119         {
1120             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend,
1121                                          ( uint32_t ) 0,
1122                                          eNoAction,
1123                                          pxHigherPriorityTaskWoken );
1124             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;
1125             xReturn = pdTRUE;
1126         }
1127         else
1128         {
1129             xReturn = pdFALSE;
1130         }
1131     }
1132     portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );
1133
1134     return xReturn;
1135 }
1136 /*-----------------------------------------------------------*/
1137
1138 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
1139                                      const uint8_t * pucData,
1140                                      size_t xCount,
1141                                      size_t xHead )
1142 {
1143     size_t xFirstLength;
1144
1145     configASSERT( xCount > ( size_t ) 0 );
1146
1147     /* Calculate the number of bytes that can be added in the first write -
1148      * which may be less than the total number of bytes that need to be added if
1149      * the buffer will wrap back to the beginning. */
1150     xFirstLength = configMIN( pxStreamBuffer->xLength - xHead, xCount );
1151
1152     /* Write as many bytes as can be written in the first write. */
1153     configASSERT( ( xHead + xFirstLength ) <= pxStreamBuffer->xLength );
1154     ( void ) memcpy( ( void * ) ( &( pxStreamBuffer->pucBuffer[ xHead ] ) ), ( const void * ) pucData, xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1155
1156     /* If the number of bytes written was less than the number that could be
1157      * written in the first write... */
1158     if( xCount > xFirstLength )
1159     {
1160         /* ...then write the remaining bytes to the start of the buffer. */
1161         configASSERT( ( xCount - xFirstLength ) <= pxStreamBuffer->xLength );
1162         ( void ) memcpy( ( void * ) pxStreamBuffer->pucBuffer, ( const void * ) &( pucData[ xFirstLength ] ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1163     }
1164     else
1165     {
1166         mtCOVERAGE_TEST_MARKER();
1167     }
1168
1169     xHead += xCount;
1170
1171     if( xHead >= pxStreamBuffer->xLength )
1172     {
1173         xHead -= pxStreamBuffer->xLength;
1174     }
1175     else
1176     {
1177         mtCOVERAGE_TEST_MARKER();
1178     }
1179
1180     return xHead;
1181 }
1182 /*-----------------------------------------------------------*/
1183
1184 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
1185                                       uint8_t * pucData,
1186                                       size_t xCount,
1187                                       size_t xTail )
1188 {
1189     size_t xFirstLength;
1190
1191     configASSERT( xCount != ( size_t ) 0 );
1192
1193     /* Calculate the number of bytes that can be read - which may be
1194      * less than the number wanted if the data wraps around to the start of
1195      * the buffer. */
1196     xFirstLength = configMIN( pxStreamBuffer->xLength - xTail, xCount );
1197
1198     /* Obtain the number of bytes it is possible to obtain in the first
1199      * read.  Asserts check bounds of read and write. */
1200     configASSERT( xFirstLength <= xCount );
1201     configASSERT( ( xTail + xFirstLength ) <= pxStreamBuffer->xLength );
1202     ( void ) memcpy( ( void * ) pucData, ( const void * ) &( pxStreamBuffer->pucBuffer[ xTail ] ), xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1203
1204     /* If the total number of wanted bytes is greater than the number
1205      * that could be read in the first read... */
1206     if( xCount > xFirstLength )
1207     {
1208         /* ...then read the remaining bytes from the start of the buffer. */
1209         configASSERT( xCount <= xCount );
1210         ( void ) memcpy( ( void * ) &( pucData[ xFirstLength ] ), ( void * ) ( pxStreamBuffer->pucBuffer ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1211     }
1212     else
1213     {
1214         mtCOVERAGE_TEST_MARKER();
1215     }
1216
1217     /* Move the tail pointer to effectively remove the data read from the buffer. */
1218     xTail += xCount;
1219
1220     if( xTail >= pxStreamBuffer->xLength )
1221     {
1222         xTail -= pxStreamBuffer->xLength;
1223     }
1224
1225     return xTail;
1226 }
1227 /*-----------------------------------------------------------*/
1228
1229 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer )
1230 {
1231 /* Returns the distance between xTail and xHead. */
1232     size_t xCount;
1233
1234     xCount = pxStreamBuffer->xLength + pxStreamBuffer->xHead;
1235     xCount -= pxStreamBuffer->xTail;
1236
1237     if( xCount >= pxStreamBuffer->xLength )
1238     {
1239         xCount -= pxStreamBuffer->xLength;
1240     }
1241     else
1242     {
1243         mtCOVERAGE_TEST_MARKER();
1244     }
1245
1246     return xCount;
1247 }
1248 /*-----------------------------------------------------------*/
1249
1250 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
1251                                           uint8_t * const pucBuffer,
1252                                           size_t xBufferSizeBytes,
1253                                           size_t xTriggerLevelBytes,
1254                                           uint8_t ucFlags )
1255 {
1256     /* Assert here is deliberately writing to the entire buffer to ensure it can
1257      * be written to without generating exceptions, and is setting the buffer to a
1258      * known value to assist in development/debugging. */
1259     #if ( configASSERT_DEFINED == 1 )
1260         {
1261             /* The value written just has to be identifiable when looking at the
1262              * memory.  Don't use 0xA5 as that is the stack fill value and could
1263              * result in confusion as to what is actually being observed. */
1264             const BaseType_t xWriteValue = 0x55;
1265             configASSERT( memset( pucBuffer, ( int ) xWriteValue, xBufferSizeBytes ) == pucBuffer );
1266         } /*lint !e529 !e438 xWriteValue is only used if configASSERT() is defined. */
1267     #endif
1268
1269     ( void ) memset( ( void * ) pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) ); /*lint !e9087 memset() requires void *. */
1270     pxStreamBuffer->pucBuffer = pucBuffer;
1271     pxStreamBuffer->xLength = xBufferSizeBytes;
1272     pxStreamBuffer->xTriggerLevelBytes = xTriggerLevelBytes;
1273     pxStreamBuffer->ucFlags = ucFlags;
1274 }
1275
1276 #if ( configUSE_TRACE_FACILITY == 1 )
1277
1278     UBaseType_t uxStreamBufferGetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer )
1279     {
1280         return xStreamBuffer->uxStreamBufferNumber;
1281     }
1282
1283 #endif /* configUSE_TRACE_FACILITY */
1284 /*-----------------------------------------------------------*/
1285
1286 #if ( configUSE_TRACE_FACILITY == 1 )
1287
1288     void vStreamBufferSetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer,
1289                                              UBaseType_t uxStreamBufferNumber )
1290     {
1291         xStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
1292     }
1293
1294 #endif /* configUSE_TRACE_FACILITY */
1295 /*-----------------------------------------------------------*/
1296
1297 #if ( configUSE_TRACE_FACILITY == 1 )
1298
1299     uint8_t ucStreamBufferGetStreamBufferType( StreamBufferHandle_t xStreamBuffer )
1300     {
1301         return( xStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER );
1302     }
1303
1304 #endif /* configUSE_TRACE_FACILITY */
1305 /*-----------------------------------------------------------*/