begriffs open source - freertos/blob - stream_buffer.c

   1 /*
   2  * FreeRTOS Kernel <DEVELOPMENT BRANCH>
   3  * Copyright (C) 2021 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   4  *
   5  * SPDX-License-Identifier: MIT
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   8  * this software and associated documentation files (the "Software"), to deal in
   9  * the Software without restriction, including without limitation the rights to
  10  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  11  * the Software, and to permit persons to whom the Software is furnished to do so,
  12  * subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in all
  15  * copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  19  * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  20  * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  21  * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * https://www.FreeRTOS.org
  25  * https://github.com/FreeRTOS
  26  *
  27  */
  28
  29 /* Standard includes. */
  30 #include <string.h>
  31
  32 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
  33  * all the API functions to use the MPU wrappers.  That should only be done when
  34  * task.h is included from an application file. */
  35 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  36
  37 /* FreeRTOS includes. */
  38 #include "FreeRTOS.h"
  39 #include "task.h"
  40 #include "stream_buffer.h"
  41
  42 #if ( configUSE_TASK_NOTIFICATIONS != 1 )
  43     #error configUSE_TASK_NOTIFICATIONS must be set to 1 to build stream_buffer.c
  44 #endif
  45
  46 #if ( INCLUDE_xTaskGetCurrentTaskHandle != 1 )
  47     #error INCLUDE_xTaskGetCurrentTaskHandle must be set to 1 to build stream_buffer.c
  48 #endif
  49
  50 /* Lint e961, e9021 and e750 are suppressed as a MISRA exception justified
  51  * because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
  52  * for the header files above, but not in this file, in order to generate the
  53  * correct privileged Vs unprivileged linkage and placement. */
  54 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750 !e9021. */
  55
  56 /* If the user has not provided application specific Rx notification macros,
  57  * or #defined the notification macros away, then provide default implementations
  58  * that uses task notifications. */
  59 /*lint -save -e9026 Function like macros allowed and needed here so they can be overridden. */
  60 #ifndef sbRECEIVE_COMPLETED
  61     #define sbRECEIVE_COMPLETED( pxStreamBuffer )                         \
  62     vTaskSuspendAll();                                                    \
  63     {                                                                     \
  64         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )              \
  65         {                                                                 \
  66             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToSend, \
  67                                   ( uint32_t ) 0,                         \
  68                                   eNoAction );                            \
  69             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                \
  70         }                                                                 \
  71     }                                                                     \
  72     ( void ) xTaskResumeAll()
  73 #endif /* sbRECEIVE_COMPLETED */
  74
  75 /* If user has provided a per-instance receive complete callback, then
  76  * invoke the callback else use the receive complete macro which is provided by default for all instances.
  77  */
  78 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
  79     #define prvRECEIVE_COMPLETED( pxStreamBuffer )                                               \
  80     do {                                                                                         \
  81         if( ( pxStreamBuffer )->pxReceiveCompletedCallback != NULL )                             \
  82         {                                                                                        \
  83             ( pxStreamBuffer )->pxReceiveCompletedCallback( ( pxStreamBuffer ), pdFALSE, NULL ); \
  84         }                                                                                        \
  85         else                                                                                     \
  86         {                                                                                        \
  87             sbRECEIVE_COMPLETED( ( pxStreamBuffer ) );                                           \
  88         }                                                                                        \
  89     } while( 0 )
  90 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
  91     #define prvRECEIVE_COMPLETED( pxStreamBuffer )    sbRECEIVE_COMPLETED( ( pxStreamBuffer ) )
  92 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
  93
  94 #ifndef sbRECEIVE_COMPLETED_FROM_ISR
  95     #define sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer,                            \
  96                                           pxHigherPriorityTaskWoken )                \
  97     do {                                                                             \
  98         UBaseType_t uxSavedInterruptStatus;                                          \
  99                                                                                      \
 100         uxSavedInterruptStatus = taskENTER_CRITICAL_FROM_ISR();                      \
 101         {                                                                            \
 102             if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )                     \
 103             {                                                                        \
 104                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend, \
 105                                              ( uint32_t ) 0,                         \
 106                                              eNoAction,                              \
 107                                              ( pxHigherPriorityTaskWoken ) );        \
 108                 ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                       \
 109             }                                                                        \
 110         }                                                                            \
 111         taskEXIT_CRITICAL_FROM_ISR( uxSavedInterruptStatus );                        \
 112     } while( 0 )
 113 #endif /* sbRECEIVE_COMPLETED_FROM_ISR */
 114
 115 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 116     #define prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer,                                                               \
 117                                            pxHigherPriorityTaskWoken )                                                   \
 118     do {                                                                                                                 \
 119         if( ( pxStreamBuffer )->pxReceiveCompletedCallback != NULL )                                                     \
 120         {                                                                                                                \
 121             ( pxStreamBuffer )->pxReceiveCompletedCallback( ( pxStreamBuffer ), pdTRUE, ( pxHigherPriorityTaskWoken ) ); \
 122         }                                                                                                                \
 123         else                                                                                                             \
 124         {                                                                                                                \
 125             sbRECEIVE_COMPLETED_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) );                           \
 126         }                                                                                                                \
 127     } while( 0 )
 128 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 129     #define prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken ) \
 130     sbRECEIVE_COMPLETED_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) )
 131 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 132
 133 /* If the user has not provided an application specific Tx notification macro,
 134  * or #defined the notification macro away, then provide a default
 135  * implementation that uses task notifications.
 136  */
 137 #ifndef sbSEND_COMPLETED
 138     #define sbSEND_COMPLETED( pxStreamBuffer )                               \
 139     vTaskSuspendAll();                                                       \
 140     {                                                                        \
 141         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )              \
 142         {                                                                    \
 143             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 144                                   ( uint32_t ) 0,                            \
 145                                   eNoAction );                               \
 146             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                \
 147         }                                                                    \
 148     }                                                                        \
 149     ( void ) xTaskResumeAll()
 150 #endif /* sbSEND_COMPLETED */
 151
 152 /* If user has provided a per-instance send completed callback, then
 153  * invoke the callback else use the send complete macro which is provided by default for all instances.
 154  */
 155 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 156     #define prvSEND_COMPLETED( pxStreamBuffer )                                           \
 157     do {                                                                                  \
 158         if( ( pxStreamBuffer )->pxSendCompletedCallback != NULL )                         \
 159         {                                                                                 \
 160             pxStreamBuffer->pxSendCompletedCallback( ( pxStreamBuffer ), pdFALSE, NULL ); \
 161         }                                                                                 \
 162         else                                                                              \
 163         {                                                                                 \
 164             sbSEND_COMPLETED( ( pxStreamBuffer ) );                                       \
 165         }                                                                                 \
 166     } while( 0 )
 167 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 168     #define prvSEND_COMPLETED( pxStreamBuffer )    sbSEND_COMPLETED( ( pxStreamBuffer ) )
 169 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 170
 171
 172 #ifndef sbSEND_COMPLETE_FROM_ISR
 173     #define sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken )       \
 174     do {                                                                                \
 175         UBaseType_t uxSavedInterruptStatus;                                             \
 176                                                                                         \
 177         uxSavedInterruptStatus = taskENTER_CRITICAL_FROM_ISR();                         \
 178         {                                                                               \
 179             if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )                     \
 180             {                                                                           \
 181                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 182                                              ( uint32_t ) 0,                            \
 183                                              eNoAction,                                 \
 184                                              ( pxHigherPriorityTaskWoken ) );           \
 185                 ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                       \
 186             }                                                                           \
 187         }                                                                               \
 188         taskEXIT_CRITICAL_FROM_ISR( uxSavedInterruptStatus );                           \
 189     } while( 0 )
 190 #endif /* sbSEND_COMPLETE_FROM_ISR */
 191
 192
 193 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 194     #define prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken )                                    \
 195     do {                                                                                                              \
 196         if( ( pxStreamBuffer )->pxSendCompletedCallback != NULL )                                                     \
 197         {                                                                                                             \
 198             ( pxStreamBuffer )->pxSendCompletedCallback( ( pxStreamBuffer ), pdTRUE, ( pxHigherPriorityTaskWoken ) ); \
 199         }                                                                                                             \
 200         else                                                                                                          \
 201         {                                                                                                             \
 202             sbSEND_COMPLETE_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) );                            \
 203         }                                                                                                             \
 204     } while( 0 )
 205 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 206     #define prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken ) \
 207     sbSEND_COMPLETE_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) )
 208 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 209
 210 /*lint -restore (9026) */
 211
 212 /* The number of bytes used to hold the length of a message in the buffer. */
 213 #define sbBYTES_TO_STORE_MESSAGE_LENGTH    ( sizeof( configMESSAGE_BUFFER_LENGTH_TYPE ) )
 214
 215 /* Bits stored in the ucFlags field of the stream buffer. */
 216 #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. */
 217 #define sbFLAGS_IS_STATICALLY_ALLOCATED    ( ( uint8_t ) 2 ) /* Set if the stream buffer was created using statically allocated memory. */
 218
 219 /*-----------------------------------------------------------*/
 220
 221 /* Structure that hold state information on the buffer. */
 222 typedef struct StreamBufferDef_t                 /*lint !e9058 Style convention uses tag. */
 223 {
 224     volatile size_t xTail;                       /* Index to the next item to read within the buffer. */
 225     volatile size_t xHead;                       /* Index to the next item to write within the buffer. */
 226     size_t xLength;                              /* The length of the buffer pointed to by pucBuffer. */
 227     size_t xTriggerLevelBytes;                   /* The number of bytes that must be in the stream buffer before a task that is waiting for data is unblocked. */
 228     volatile TaskHandle_t xTaskWaitingToReceive; /* Holds the handle of a task waiting for data, or NULL if no tasks are waiting. */
 229     volatile TaskHandle_t xTaskWaitingToSend;    /* Holds the handle of a task waiting to send data to a message buffer that is full. */
 230     uint8_t * pucBuffer;                         /* Points to the buffer itself - that is - the RAM that stores the data passed through the buffer. */
 231     uint8_t ucFlags;
 232
 233     #if ( configUSE_TRACE_FACILITY == 1 )
 234         UBaseType_t uxStreamBufferNumber; /* Used for tracing purposes. */
 235     #endif
 236
 237     #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 238         StreamBufferCallbackFunction_t pxSendCompletedCallback;    /* Optional callback called on send complete. sbSEND_COMPLETED is called if this is NULL. */
 239         StreamBufferCallbackFunction_t pxReceiveCompletedCallback; /* Optional callback called on receive complete.  sbRECEIVE_COMPLETED is called if this is NULL. */
 240     #endif
 241 } StreamBuffer_t;
 242
 243 /*
 244  * The number of bytes available to be read from the buffer.
 245  */
 246 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer ) PRIVILEGED_FUNCTION;
 247
 248 /*
 249  * Add xCount bytes from pucData into the pxStreamBuffer's data storage area.
 250  * This function does not update the buffer's xHead pointer, so multiple writes
 251  * may be chained together "atomically". This is useful for Message Buffers where
 252  * the length and data bytes are written in two separate chunks, and we don't want
 253  * the reader to see the buffer as having grown until after all data is copied over.
 254  * This function takes a custom xHead value to indicate where to write to (necessary
 255  * for chaining) and returns the the resulting xHead position.
 256  * To mark the write as complete, manually set the buffer's xHead field with the
 257  * returned xHead from this function.
 258  */
 259 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
 260                                      const uint8_t * pucData,
 261                                      size_t xCount,
 262                                      size_t xHead ) PRIVILEGED_FUNCTION;
 263
 264 /*
 265  * If the stream buffer is being used as a message buffer, then reads an entire
 266  * message out of the buffer.  If the stream buffer is being used as a stream
 267  * buffer then read as many bytes as possible from the buffer.
 268  * prvReadBytesFromBuffer() is called to actually extract the bytes from the
 269  * buffer's data storage area.
 270  */
 271 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
 272                                         void * pvRxData,
 273                                         size_t xBufferLengthBytes,
 274                                         size_t xBytesAvailable ) PRIVILEGED_FUNCTION;
 275
 276 /*
 277  * If the stream buffer is being used as a message buffer, then writes an entire
 278  * message to the buffer.  If the stream buffer is being used as a stream
 279  * buffer then write as many bytes as possible to the buffer.
 280  * prvWriteBytestoBuffer() is called to actually send the bytes to the buffer's
 281  * data storage area.
 282  */
 283 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 284                                        const void * pvTxData,
 285                                        size_t xDataLengthBytes,
 286                                        size_t xSpace,
 287                                        size_t xRequiredSpace ) PRIVILEGED_FUNCTION;
 288
 289 /*
 290  * Copies xCount bytes from the pxStreamBuffer's data storage area to pucData.
 291  * This function does not update the buffer's xTail pointer, so multiple reads
 292  * may be chained together "atomically". This is useful for Message Buffers where
 293  * the length and data bytes are read in two separate chunks, and we don't want
 294  * the writer to see the buffer as having more free space until after all data is
 295  * copied over, especially if we have to abort the read due to insufficient receiving space.
 296  * This function takes a custom xTail value to indicate where to read from (necessary
 297  * for chaining) and returns the the resulting xTail position.
 298  * To mark the read as complete, manually set the buffer's xTail field with the
 299  * returned xTail from this function.
 300  */
 301 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
 302                                       uint8_t * pucData,
 303                                       size_t xCount,
 304                                       size_t xTail ) PRIVILEGED_FUNCTION;
 305
 306 /*
 307  * Called by both pxStreamBufferCreate() and pxStreamBufferCreateStatic() to
 308  * initialise the members of the newly created stream buffer structure.
 309  */
 310 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
 311                                           uint8_t * const pucBuffer,
 312                                           size_t xBufferSizeBytes,
 313                                           size_t xTriggerLevelBytes,
 314                                           uint8_t ucFlags,
 315                                           StreamBufferCallbackFunction_t pxSendCompletedCallback,
 316                                           StreamBufferCallbackFunction_t pxReceiveCompletedCallback ) PRIVILEGED_FUNCTION;
 317
 318 /*-----------------------------------------------------------*/
 319 #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 320     StreamBufferHandle_t xStreamBufferGenericCreate( size_t xBufferSizeBytes,
 321                                                      size_t xTriggerLevelBytes,
 322                                                      BaseType_t xIsMessageBuffer,
 323                                                      StreamBufferCallbackFunction_t pxSendCompletedCallback,
 324                                                      StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
 325     {
 326         void * pvAllocatedMemory;
 327         uint8_t ucFlags;
 328
 329         traceENTER_xStreamBufferGenericCreate( xBufferSizeBytes, xTriggerLevelBytes, xIsMessageBuffer, pxSendCompletedCallback, pxReceiveCompletedCallback );
 330
 331         /* In case the stream buffer is going to be used as a message buffer
 332          * (that is, it will hold discrete messages with a little meta data that
 333          * says how big the next message is) check the buffer will be large enough
 334          * to hold at least one message. */
 335         if( xIsMessageBuffer == pdTRUE )
 336         {
 337             /* Is a message buffer but not statically allocated. */
 338             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER;
 339             configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 340         }
 341         else
 342         {
 343             /* Not a message buffer and not statically allocated. */
 344             ucFlags = 0;
 345             configASSERT( xBufferSizeBytes > 0 );
 346         }
 347
 348         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 349
 350         /* A trigger level of 0 would cause a waiting task to unblock even when
 351          * the buffer was empty. */
 352         if( xTriggerLevelBytes == ( size_t ) 0 )
 353         {
 354             xTriggerLevelBytes = ( size_t ) 1;
 355         }
 356
 357         /* A stream buffer requires a StreamBuffer_t structure and a buffer.
 358          * Both are allocated in a single call to pvPortMalloc().  The
 359          * StreamBuffer_t structure is placed at the start of the allocated memory
 360          * and the buffer follows immediately after.  The requested size is
 361          * incremented so the free space is returned as the user would expect -
 362          * this is a quirk of the implementation that means otherwise the free
 363          * space would be reported as one byte smaller than would be logically
 364          * expected. */
 365         if( xBufferSizeBytes < ( xBufferSizeBytes + 1U + sizeof( StreamBuffer_t ) ) )
 366         {
 367             xBufferSizeBytes++;
 368             pvAllocatedMemory = pvPortMalloc( xBufferSizeBytes + sizeof( StreamBuffer_t ) );
 369         }
 370         else
 371         {
 372             pvAllocatedMemory = NULL;
 373         }
 374
 375         if( pvAllocatedMemory != NULL )
 376         {
 377             prvInitialiseNewStreamBuffer( ( StreamBuffer_t * ) pvAllocatedMemory,                         /* 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. */
 378                                           ( ( uint8_t * ) pvAllocatedMemory ) + sizeof( StreamBuffer_t ), /* Storage area follows. */ /*lint !e9016 Indexing past structure valid for uint8_t pointer, also storage area has no alignment requirement. */
 379                                           xBufferSizeBytes,
 380                                           xTriggerLevelBytes,
 381                                           ucFlags,
 382                                           pxSendCompletedCallback,
 383                                           pxReceiveCompletedCallback );
 384
 385             traceSTREAM_BUFFER_CREATE( ( ( StreamBuffer_t * ) pvAllocatedMemory ), xIsMessageBuffer );
 386         }
 387         else
 388         {
 389             traceSTREAM_BUFFER_CREATE_FAILED( xIsMessageBuffer );
 390         }
 391
 392         traceRETURN_xStreamBufferGenericCreate( pvAllocatedMemory );
 393
 394         return ( StreamBufferHandle_t ) pvAllocatedMemory; /*lint !e9087 !e826 Safe cast as allocated memory is aligned. */
 395     }
 396 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
 397 /*-----------------------------------------------------------*/
 398
 399 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
 400
 401     StreamBufferHandle_t xStreamBufferGenericCreateStatic( size_t xBufferSizeBytes,
 402                                                            size_t xTriggerLevelBytes,
 403                                                            BaseType_t xIsMessageBuffer,
 404                                                            uint8_t * const pucStreamBufferStorageArea,
 405                                                            StaticStreamBuffer_t * const pxStaticStreamBuffer,
 406                                                            StreamBufferCallbackFunction_t pxSendCompletedCallback,
 407                                                            StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
 408     {
 409         /* MISRA Ref 11.3.1 [Misaligned access] */
 410         /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
 411         /* coverity[misra_c_2012_rule_11_3_violation] */
 412         StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer;
 413         StreamBufferHandle_t xReturn;
 414         uint8_t ucFlags;
 415
 416         traceENTER_xStreamBufferGenericCreateStatic( xBufferSizeBytes, xTriggerLevelBytes, xIsMessageBuffer, pucStreamBufferStorageArea, pxStaticStreamBuffer, pxSendCompletedCallback, pxReceiveCompletedCallback );
 417
 418         configASSERT( pucStreamBufferStorageArea );
 419         configASSERT( pxStaticStreamBuffer );
 420         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 421
 422         /* A trigger level of 0 would cause a waiting task to unblock even when
 423          * the buffer was empty. */
 424         if( xTriggerLevelBytes == ( size_t ) 0 )
 425         {
 426             xTriggerLevelBytes = ( size_t ) 1;
 427         }
 428
 429         /* In case the stream buffer is going to be used as a message buffer
 430          * (that is, it will hold discrete messages with a little meta data that
 431          * says how big the next message is) check the buffer will be large enough
 432          * to hold at least one message. */
 433
 434         if( xIsMessageBuffer != pdFALSE )
 435         {
 436             /* Statically allocated message buffer. */
 437             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER | sbFLAGS_IS_STATICALLY_ALLOCATED;
 438             configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 439         }
 440         else
 441         {
 442             /* Statically allocated stream buffer. */
 443             ucFlags = sbFLAGS_IS_STATICALLY_ALLOCATED;
 444         }
 445
 446         #if ( configASSERT_DEFINED == 1 )
 447         {
 448             /* Sanity check that the size of the structure used to declare a
 449              * variable of type StaticStreamBuffer_t equals the size of the real
 450              * message buffer structure. */
 451             volatile size_t xSize = sizeof( StaticStreamBuffer_t );
 452             configASSERT( xSize == sizeof( StreamBuffer_t ) );
 453         } /*lint !e529 xSize is referenced is configASSERT() is defined. */
 454         #endif /* configASSERT_DEFINED */
 455
 456         if( ( pucStreamBufferStorageArea != NULL ) && ( pxStaticStreamBuffer != NULL ) )
 457         {
 458             prvInitialiseNewStreamBuffer( pxStreamBuffer,
 459                                           pucStreamBufferStorageArea,
 460                                           xBufferSizeBytes,
 461                                           xTriggerLevelBytes,
 462                                           ucFlags,
 463                                           pxSendCompletedCallback,
 464                                           pxReceiveCompletedCallback );
 465
 466             /* Remember this was statically allocated in case it is ever deleted
 467              * again. */
 468             pxStreamBuffer->ucFlags |= sbFLAGS_IS_STATICALLY_ALLOCATED;
 469
 470             traceSTREAM_BUFFER_CREATE( pxStreamBuffer, xIsMessageBuffer );
 471
 472             /* MISRA Ref 11.3.1 [Misaligned access] */
 473             /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
 474             /* coverity[misra_c_2012_rule_11_3_violation] */
 475             xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer;
 476         }
 477         else
 478         {
 479             xReturn = NULL;
 480             traceSTREAM_BUFFER_CREATE_STATIC_FAILED( xReturn, xIsMessageBuffer );
 481         }
 482
 483         traceRETURN_xStreamBufferGenericCreateStatic( xReturn );
 484
 485         return xReturn;
 486     }
 487 #endif /* ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
 488 /*-----------------------------------------------------------*/
 489
 490 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
 491     BaseType_t xStreamBufferGetStaticBuffers( StreamBufferHandle_t xStreamBuffer,
 492                                               uint8_t ** ppucStreamBufferStorageArea,
 493                                               StaticStreamBuffer_t ** ppxStaticStreamBuffer )
 494     {
 495         BaseType_t xReturn;
 496         StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 497
 498         traceENTER_xStreamBufferGetStaticBuffers( xStreamBuffer, ppucStreamBufferStorageArea, ppxStaticStreamBuffer );
 499
 500         configASSERT( pxStreamBuffer );
 501         configASSERT( ppucStreamBufferStorageArea );
 502         configASSERT( ppxStaticStreamBuffer );
 503
 504         if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) != ( uint8_t ) 0 )
 505         {
 506             *ppucStreamBufferStorageArea = pxStreamBuffer->pucBuffer;
 507             /* MISRA Ref 11.3.1 [Misaligned access] */
 508             /* More details at: https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/MISRA.md#rule-113 */
 509             /* coverity[misra_c_2012_rule_11_3_violation] */
 510             *ppxStaticStreamBuffer = ( StaticStreamBuffer_t * ) pxStreamBuffer;
 511             xReturn = pdTRUE;
 512         }
 513         else
 514         {
 515             xReturn = pdFALSE;
 516         }
 517
 518         traceRETURN_xStreamBufferGetStaticBuffers( xReturn );
 519
 520         return xReturn;
 521     }
 522 #endif /* configSUPPORT_STATIC_ALLOCATION */
 523 /*-----------------------------------------------------------*/
 524
 525 void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer )
 526 {
 527     StreamBuffer_t * pxStreamBuffer = xStreamBuffer;
 528
 529     traceENTER_vStreamBufferDelete( xStreamBuffer );
 530
 531     configASSERT( pxStreamBuffer );
 532
 533     traceSTREAM_BUFFER_DELETE( xStreamBuffer );
 534
 535     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) == ( uint8_t ) pdFALSE )
 536     {
 537         #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 538         {
 539             /* Both the structure and the buffer were allocated using a single call
 540             * to pvPortMalloc(), hence only one call to vPortFree() is required. */
 541             vPortFree( ( void * ) pxStreamBuffer ); /*lint !e9087 Standard free() semantics require void *, plus pxStreamBuffer was allocated by pvPortMalloc(). */
 542         }
 543         #else
 544         {
 545             /* Should not be possible to get here, ucFlags must be corrupt.
 546              * Force an assert. */
 547             configASSERT( xStreamBuffer == ( StreamBufferHandle_t ) ~0 );
 548         }
 549         #endif
 550     }
 551     else
 552     {
 553         /* The structure and buffer were not allocated dynamically and cannot be
 554          * freed - just scrub the structure so future use will assert. */
 555         ( void ) memset( pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) );
 556     }
 557
 558     traceRETURN_vStreamBufferDelete();
 559 }
 560 /*-----------------------------------------------------------*/
 561
 562 BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer )
 563 {
 564     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 565     BaseType_t xReturn = pdFAIL;
 566     StreamBufferCallbackFunction_t pxSendCallback = NULL, pxReceiveCallback = NULL;
 567
 568     #if ( configUSE_TRACE_FACILITY == 1 )
 569         UBaseType_t uxStreamBufferNumber;
 570     #endif
 571
 572     traceENTER_xStreamBufferReset( xStreamBuffer );
 573
 574     configASSERT( pxStreamBuffer );
 575
 576     #if ( configUSE_TRACE_FACILITY == 1 )
 577     {
 578         /* Store the stream buffer number so it can be restored after the
 579          * reset. */
 580         uxStreamBufferNumber = pxStreamBuffer->uxStreamBufferNumber;
 581     }
 582     #endif
 583
 584     /* Can only reset a message buffer if there are no tasks blocked on it. */
 585     taskENTER_CRITICAL();
 586     {
 587         if( ( pxStreamBuffer->xTaskWaitingToReceive == NULL ) && ( pxStreamBuffer->xTaskWaitingToSend == NULL ) )
 588         {
 589             #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 590             {
 591                 pxSendCallback = pxStreamBuffer->pxSendCompletedCallback;
 592                 pxReceiveCallback = pxStreamBuffer->pxReceiveCompletedCallback;
 593             }
 594             #endif
 595
 596             prvInitialiseNewStreamBuffer( pxStreamBuffer,
 597                                           pxStreamBuffer->pucBuffer,
 598                                           pxStreamBuffer->xLength,
 599                                           pxStreamBuffer->xTriggerLevelBytes,
 600                                           pxStreamBuffer->ucFlags,
 601                                           pxSendCallback,
 602                                           pxReceiveCallback );
 603
 604             #if ( configUSE_TRACE_FACILITY == 1 )
 605             {
 606                 pxStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
 607             }
 608             #endif
 609
 610             traceSTREAM_BUFFER_RESET( xStreamBuffer );
 611
 612             xReturn = pdPASS;
 613         }
 614     }
 615     taskEXIT_CRITICAL();
 616
 617     traceRETURN_xStreamBufferReset( xReturn );
 618
 619     return xReturn;
 620 }
 621 /*-----------------------------------------------------------*/
 622
 623 BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer,
 624                                          size_t xTriggerLevel )
 625 {
 626     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 627     BaseType_t xReturn;
 628
 629     traceENTER_xStreamBufferSetTriggerLevel( xStreamBuffer, xTriggerLevel );
 630
 631     configASSERT( pxStreamBuffer );
 632
 633     /* It is not valid for the trigger level to be 0. */
 634     if( xTriggerLevel == ( size_t ) 0 )
 635     {
 636         xTriggerLevel = ( size_t ) 1;
 637     }
 638
 639     /* The trigger level is the number of bytes that must be in the stream
 640      * buffer before a task that is waiting for data is unblocked. */
 641     if( xTriggerLevel < pxStreamBuffer->xLength )
 642     {
 643         pxStreamBuffer->xTriggerLevelBytes = xTriggerLevel;
 644         xReturn = pdPASS;
 645     }
 646     else
 647     {
 648         xReturn = pdFALSE;
 649     }
 650
 651     traceRETURN_xStreamBufferSetTriggerLevel( xReturn );
 652
 653     return xReturn;
 654 }
 655 /*-----------------------------------------------------------*/
 656
 657 size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer )
 658 {
 659     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 660     size_t xSpace;
 661     size_t xOriginalTail;
 662
 663     traceENTER_xStreamBufferSpacesAvailable( xStreamBuffer );
 664
 665     configASSERT( pxStreamBuffer );
 666
 667     /* The code below reads xTail and then xHead.  This is safe if the stream
 668      * buffer is updated once between the two reads - but not if the stream buffer
 669      * is updated more than once between the two reads - hence the loop. */
 670     do
 671     {
 672         xOriginalTail = pxStreamBuffer->xTail;
 673         xSpace = pxStreamBuffer->xLength + pxStreamBuffer->xTail;
 674         xSpace -= pxStreamBuffer->xHead;
 675     } while( xOriginalTail != pxStreamBuffer->xTail );
 676
 677     xSpace -= ( size_t ) 1;
 678
 679     if( xSpace >= pxStreamBuffer->xLength )
 680     {
 681         xSpace -= pxStreamBuffer->xLength;
 682     }
 683     else
 684     {
 685         mtCOVERAGE_TEST_MARKER();
 686     }
 687
 688     traceRETURN_xStreamBufferSpacesAvailable( xSpace );
 689
 690     return xSpace;
 691 }
 692 /*-----------------------------------------------------------*/
 693
 694 size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer )
 695 {
 696     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 697     size_t xReturn;
 698
 699     traceENTER_xStreamBufferBytesAvailable( xStreamBuffer );
 700
 701     configASSERT( pxStreamBuffer );
 702
 703     xReturn = prvBytesInBuffer( pxStreamBuffer );
 704
 705     traceRETURN_xStreamBufferBytesAvailable( xReturn );
 706
 707     return xReturn;
 708 }
 709 /*-----------------------------------------------------------*/
 710
 711 size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
 712                           const void * pvTxData,
 713                           size_t xDataLengthBytes,
 714                           TickType_t xTicksToWait )
 715 {
 716     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 717     size_t xReturn, xSpace = 0;
 718     size_t xRequiredSpace = xDataLengthBytes;
 719     TimeOut_t xTimeOut;
 720     size_t xMaxReportedSpace = 0;
 721
 722     traceENTER_xStreamBufferSend( xStreamBuffer, pvTxData, xDataLengthBytes, xTicksToWait );
 723
 724     configASSERT( pvTxData );
 725     configASSERT( pxStreamBuffer );
 726
 727     /* The maximum amount of space a stream buffer will ever report is its length
 728      * minus 1. */
 729     xMaxReportedSpace = pxStreamBuffer->xLength - ( size_t ) 1;
 730
 731     /* This send function is used to write to both message buffers and stream
 732      * buffers.  If this is a message buffer then the space needed must be
 733      * increased by the amount of bytes needed to store the length of the
 734      * message. */
 735     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 736     {
 737         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 738
 739         /* Overflow? */
 740         configASSERT( xRequiredSpace > xDataLengthBytes );
 741
 742         /* If this is a message buffer then it must be possible to write the
 743          * whole message. */
 744         if( xRequiredSpace > xMaxReportedSpace )
 745         {
 746             /* The message would not fit even if the entire buffer was empty,
 747              * so don't wait for space. */
 748             xTicksToWait = ( TickType_t ) 0;
 749         }
 750         else
 751         {
 752             mtCOVERAGE_TEST_MARKER();
 753         }
 754     }
 755     else
 756     {
 757         /* If this is a stream buffer then it is acceptable to write only part
 758          * of the message to the buffer.  Cap the length to the total length of
 759          * the buffer. */
 760         if( xRequiredSpace > xMaxReportedSpace )
 761         {
 762             xRequiredSpace = xMaxReportedSpace;
 763         }
 764         else
 765         {
 766             mtCOVERAGE_TEST_MARKER();
 767         }
 768     }
 769
 770     if( xTicksToWait != ( TickType_t ) 0 )
 771     {
 772         vTaskSetTimeOutState( &xTimeOut );
 773
 774         do
 775         {
 776             /* Wait until the required number of bytes are free in the message
 777              * buffer. */
 778             taskENTER_CRITICAL();
 779             {
 780                 xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 781
 782                 if( xSpace < xRequiredSpace )
 783                 {
 784                     /* Clear notification state as going to wait for space. */
 785                     ( void ) xTaskNotifyStateClear( NULL );
 786
 787                     /* Should only be one writer. */
 788                     configASSERT( pxStreamBuffer->xTaskWaitingToSend == NULL );
 789                     pxStreamBuffer->xTaskWaitingToSend = xTaskGetCurrentTaskHandle();
 790                 }
 791                 else
 792                 {
 793                     taskEXIT_CRITICAL();
 794                     break;
 795                 }
 796             }
 797             taskEXIT_CRITICAL();
 798
 799             traceBLOCKING_ON_STREAM_BUFFER_SEND( xStreamBuffer );
 800             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
 801             pxStreamBuffer->xTaskWaitingToSend = NULL;
 802         } while( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE );
 803     }
 804     else
 805     {
 806         mtCOVERAGE_TEST_MARKER();
 807     }
 808
 809     if( xSpace == ( size_t ) 0 )
 810     {
 811         xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 812     }
 813     else
 814     {
 815         mtCOVERAGE_TEST_MARKER();
 816     }
 817
 818     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 819
 820     if( xReturn > ( size_t ) 0 )
 821     {
 822         traceSTREAM_BUFFER_SEND( xStreamBuffer, xReturn );
 823
 824         /* Was a task waiting for the data? */
 825         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 826         {
 827             prvSEND_COMPLETED( pxStreamBuffer );
 828         }
 829         else
 830         {
 831             mtCOVERAGE_TEST_MARKER();
 832         }
 833     }
 834     else
 835     {
 836         mtCOVERAGE_TEST_MARKER();
 837         traceSTREAM_BUFFER_SEND_FAILED( xStreamBuffer );
 838     }
 839
 840     traceRETURN_xStreamBufferSend( xReturn );
 841
 842     return xReturn;
 843 }
 844 /*-----------------------------------------------------------*/
 845
 846 size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
 847                                  const void * pvTxData,
 848                                  size_t xDataLengthBytes,
 849                                  BaseType_t * const pxHigherPriorityTaskWoken )
 850 {
 851     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 852     size_t xReturn, xSpace;
 853     size_t xRequiredSpace = xDataLengthBytes;
 854
 855     traceENTER_xStreamBufferSendFromISR( xStreamBuffer, pvTxData, xDataLengthBytes, pxHigherPriorityTaskWoken );
 856
 857     configASSERT( pvTxData );
 858     configASSERT( pxStreamBuffer );
 859
 860     /* This send function is used to write to both message buffers and stream
 861      * buffers.  If this is a message buffer then the space needed must be
 862      * increased by the amount of bytes needed to store the length of the
 863      * message. */
 864     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 865     {
 866         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 867     }
 868     else
 869     {
 870         mtCOVERAGE_TEST_MARKER();
 871     }
 872
 873     xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 874     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 875
 876     if( xReturn > ( size_t ) 0 )
 877     {
 878         /* Was a task waiting for the data? */
 879         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 880         {
 881             prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
 882         }
 883         else
 884         {
 885             mtCOVERAGE_TEST_MARKER();
 886         }
 887     }
 888     else
 889     {
 890         mtCOVERAGE_TEST_MARKER();
 891     }
 892
 893     traceSTREAM_BUFFER_SEND_FROM_ISR( xStreamBuffer, xReturn );
 894     traceRETURN_xStreamBufferSendFromISR( xReturn );
 895
 896     return xReturn;
 897 }
 898 /*-----------------------------------------------------------*/
 899
 900 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 901                                        const void * pvTxData,
 902                                        size_t xDataLengthBytes,
 903                                        size_t xSpace,
 904                                        size_t xRequiredSpace )
 905 {
 906     size_t xNextHead = pxStreamBuffer->xHead;
 907     configMESSAGE_BUFFER_LENGTH_TYPE xMessageLength;
 908
 909     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 910     {
 911         /* This is a message buffer, as opposed to a stream buffer. */
 912
 913         /* Convert xDataLengthBytes to the message length type. */
 914         xMessageLength = ( configMESSAGE_BUFFER_LENGTH_TYPE ) xDataLengthBytes;
 915
 916         /* Ensure the data length given fits within configMESSAGE_BUFFER_LENGTH_TYPE. */
 917         configASSERT( ( size_t ) xMessageLength == xDataLengthBytes );
 918
 919         if( xSpace >= xRequiredSpace )
 920         {
 921             /* There is enough space to write both the message length and the message
 922              * itself into the buffer.  Start by writing the length of the data, the data
 923              * itself will be written later in this function. */
 924             xNextHead = prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) &( xMessageLength ), sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextHead );
 925         }
 926         else
 927         {
 928             /* Not enough space, so do not write data to the buffer. */
 929             xDataLengthBytes = 0;
 930         }
 931     }
 932     else
 933     {
 934         /* This is a stream buffer, as opposed to a message buffer, so writing a
 935          * stream of bytes rather than discrete messages.  Plan to write as many
 936          * bytes as possible. */
 937         xDataLengthBytes = configMIN( xDataLengthBytes, xSpace );
 938     }
 939
 940     if( xDataLengthBytes != ( size_t ) 0 )
 941     {
 942         /* Write the data to the buffer. */
 943         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. */
 944     }
 945
 946     return xDataLengthBytes;
 947 }
 948 /*-----------------------------------------------------------*/
 949
 950 size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
 951                              void * pvRxData,
 952                              size_t xBufferLengthBytes,
 953                              TickType_t xTicksToWait )
 954 {
 955     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 956     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
 957
 958     traceENTER_xStreamBufferReceive( xStreamBuffer, pvRxData, xBufferLengthBytes, xTicksToWait );
 959
 960     configASSERT( pvRxData );
 961     configASSERT( pxStreamBuffer );
 962
 963     /* This receive function is used by both message buffers, which store
 964      * discrete messages, and stream buffers, which store a continuous stream of
 965      * bytes.  Discrete messages include an additional
 966      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
 967      * message. */
 968     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 969     {
 970         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
 971     }
 972     else
 973     {
 974         xBytesToStoreMessageLength = 0;
 975     }
 976
 977     if( xTicksToWait != ( TickType_t ) 0 )
 978     {
 979         /* Checking if there is data and clearing the notification state must be
 980          * performed atomically. */
 981         taskENTER_CRITICAL();
 982         {
 983             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 984
 985             /* If this function was invoked by a message buffer read then
 986              * xBytesToStoreMessageLength holds the number of bytes used to hold
 987              * the length of the next discrete message.  If this function was
 988              * invoked by a stream buffer read then xBytesToStoreMessageLength will
 989              * be 0. */
 990             if( xBytesAvailable <= xBytesToStoreMessageLength )
 991             {
 992                 /* Clear notification state as going to wait for data. */
 993                 ( void ) xTaskNotifyStateClear( NULL );
 994
 995                 /* Should only be one reader. */
 996                 configASSERT( pxStreamBuffer->xTaskWaitingToReceive == NULL );
 997                 pxStreamBuffer->xTaskWaitingToReceive = xTaskGetCurrentTaskHandle();
 998             }
 999             else
1000             {
1001                 mtCOVERAGE_TEST_MARKER();
1002             }
1003         }
1004         taskEXIT_CRITICAL();
1005
1006         if( xBytesAvailable <= xBytesToStoreMessageLength )
1007         {
1008             /* Wait for data to be available. */
1009             traceBLOCKING_ON_STREAM_BUFFER_RECEIVE( xStreamBuffer );
1010             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
1011             pxStreamBuffer->xTaskWaitingToReceive = NULL;
1012
1013             /* Recheck the data available after blocking. */
1014             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1015         }
1016         else
1017         {
1018             mtCOVERAGE_TEST_MARKER();
1019         }
1020     }
1021     else
1022     {
1023         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1024     }
1025
1026     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
1027      * holds the number of bytes used to store the message length) or a stream of
1028      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
1029      * available must be greater than xBytesToStoreMessageLength to be able to
1030      * read bytes from the buffer. */
1031     if( xBytesAvailable > xBytesToStoreMessageLength )
1032     {
1033         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
1034
1035         /* Was a task waiting for space in the buffer? */
1036         if( xReceivedLength != ( size_t ) 0 )
1037         {
1038             traceSTREAM_BUFFER_RECEIVE( xStreamBuffer, xReceivedLength );
1039             prvRECEIVE_COMPLETED( xStreamBuffer );
1040         }
1041         else
1042         {
1043             mtCOVERAGE_TEST_MARKER();
1044         }
1045     }
1046     else
1047     {
1048         traceSTREAM_BUFFER_RECEIVE_FAILED( xStreamBuffer );
1049         mtCOVERAGE_TEST_MARKER();
1050     }
1051
1052     traceRETURN_xStreamBufferReceive( xReceivedLength );
1053
1054     return xReceivedLength;
1055 }
1056 /*-----------------------------------------------------------*/
1057
1058 size_t xStreamBufferNextMessageLengthBytes( StreamBufferHandle_t xStreamBuffer )
1059 {
1060     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1061     size_t xReturn, xBytesAvailable;
1062     configMESSAGE_BUFFER_LENGTH_TYPE xTempReturn;
1063
1064     traceENTER_xStreamBufferNextMessageLengthBytes( xStreamBuffer );
1065
1066     configASSERT( pxStreamBuffer );
1067
1068     /* Ensure the stream buffer is being used as a message buffer. */
1069     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1070     {
1071         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1072
1073         if( xBytesAvailable > sbBYTES_TO_STORE_MESSAGE_LENGTH )
1074         {
1075             /* The number of bytes available is greater than the number of bytes
1076              * required to hold the length of the next message, so another message
1077              * is available. */
1078             ( void ) prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempReturn, sbBYTES_TO_STORE_MESSAGE_LENGTH, pxStreamBuffer->xTail );
1079             xReturn = ( size_t ) xTempReturn;
1080         }
1081         else
1082         {
1083             /* The minimum amount of bytes in a message buffer is
1084              * ( sbBYTES_TO_STORE_MESSAGE_LENGTH + 1 ), so if xBytesAvailable is
1085              * less than sbBYTES_TO_STORE_MESSAGE_LENGTH the only other valid
1086              * value is 0. */
1087             configASSERT( xBytesAvailable == 0 );
1088             xReturn = 0;
1089         }
1090     }
1091     else
1092     {
1093         xReturn = 0;
1094     }
1095
1096     traceRETURN_xStreamBufferNextMessageLengthBytes( xReturn );
1097
1098     return xReturn;
1099 }
1100 /*-----------------------------------------------------------*/
1101
1102 size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
1103                                     void * pvRxData,
1104                                     size_t xBufferLengthBytes,
1105                                     BaseType_t * const pxHigherPriorityTaskWoken )
1106 {
1107     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1108     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
1109
1110     traceENTER_xStreamBufferReceiveFromISR( xStreamBuffer, pvRxData, xBufferLengthBytes, pxHigherPriorityTaskWoken );
1111
1112     configASSERT( pvRxData );
1113     configASSERT( pxStreamBuffer );
1114
1115     /* This receive function is used by both message buffers, which store
1116      * discrete messages, and stream buffers, which store a continuous stream of
1117      * bytes.  Discrete messages include an additional
1118      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
1119      * message. */
1120     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1121     {
1122         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
1123     }
1124     else
1125     {
1126         xBytesToStoreMessageLength = 0;
1127     }
1128
1129     xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1130
1131     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
1132      * holds the number of bytes used to store the message length) or a stream of
1133      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
1134      * available must be greater than xBytesToStoreMessageLength to be able to
1135      * read bytes from the buffer. */
1136     if( xBytesAvailable > xBytesToStoreMessageLength )
1137     {
1138         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
1139
1140         /* Was a task waiting for space in the buffer? */
1141         if( xReceivedLength != ( size_t ) 0 )
1142         {
1143             prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
1144         }
1145         else
1146         {
1147             mtCOVERAGE_TEST_MARKER();
1148         }
1149     }
1150     else
1151     {
1152         mtCOVERAGE_TEST_MARKER();
1153     }
1154
1155     traceSTREAM_BUFFER_RECEIVE_FROM_ISR( xStreamBuffer, xReceivedLength );
1156     traceRETURN_xStreamBufferReceiveFromISR( xReceivedLength );
1157
1158     return xReceivedLength;
1159 }
1160 /*-----------------------------------------------------------*/
1161
1162 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
1163                                         void * pvRxData,
1164                                         size_t xBufferLengthBytes,
1165                                         size_t xBytesAvailable )
1166 {
1167     size_t xCount, xNextMessageLength;
1168     configMESSAGE_BUFFER_LENGTH_TYPE xTempNextMessageLength;
1169     size_t xNextTail = pxStreamBuffer->xTail;
1170
1171     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1172     {
1173         /* A discrete message is being received.  First receive the length
1174          * of the message. */
1175         xNextTail = prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempNextMessageLength, sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextTail );
1176         xNextMessageLength = ( size_t ) xTempNextMessageLength;
1177
1178         /* Reduce the number of bytes available by the number of bytes just
1179          * read out. */
1180         xBytesAvailable -= sbBYTES_TO_STORE_MESSAGE_LENGTH;
1181
1182         /* Check there is enough space in the buffer provided by the
1183          * user. */
1184         if( xNextMessageLength > xBufferLengthBytes )
1185         {
1186             /* The user has provided insufficient space to read the message. */
1187             xNextMessageLength = 0;
1188         }
1189         else
1190         {
1191             mtCOVERAGE_TEST_MARKER();
1192         }
1193     }
1194     else
1195     {
1196         /* A stream of bytes is being received (as opposed to a discrete
1197          * message), so read as many bytes as possible. */
1198         xNextMessageLength = xBufferLengthBytes;
1199     }
1200
1201     /* Use the minimum of the wanted bytes and the available bytes. */
1202     xCount = configMIN( xNextMessageLength, xBytesAvailable );
1203
1204     if( xCount != ( size_t ) 0 )
1205     {
1206         /* Read the actual data and update the tail to mark the data as officially consumed. */
1207         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. */
1208     }
1209
1210     return xCount;
1211 }
1212 /*-----------------------------------------------------------*/
1213
1214 BaseType_t xStreamBufferIsEmpty( StreamBufferHandle_t xStreamBuffer )
1215 {
1216     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1217     BaseType_t xReturn;
1218     size_t xTail;
1219
1220     traceENTER_xStreamBufferIsEmpty( xStreamBuffer );
1221
1222     configASSERT( pxStreamBuffer );
1223
1224     /* True if no bytes are available. */
1225     xTail = pxStreamBuffer->xTail;
1226
1227     if( pxStreamBuffer->xHead == xTail )
1228     {
1229         xReturn = pdTRUE;
1230     }
1231     else
1232     {
1233         xReturn = pdFALSE;
1234     }
1235
1236     traceRETURN_xStreamBufferIsEmpty( xReturn );
1237
1238     return xReturn;
1239 }
1240 /*-----------------------------------------------------------*/
1241
1242 BaseType_t xStreamBufferIsFull( StreamBufferHandle_t xStreamBuffer )
1243 {
1244     BaseType_t xReturn;
1245     size_t xBytesToStoreMessageLength;
1246     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1247
1248     traceENTER_xStreamBufferIsFull( xStreamBuffer );
1249
1250     configASSERT( pxStreamBuffer );
1251
1252     /* This generic version of the receive function is used by both message
1253      * buffers, which store discrete messages, and stream buffers, which store a
1254      * continuous stream of bytes.  Discrete messages include an additional
1255      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the message. */
1256     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1257     {
1258         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
1259     }
1260     else
1261     {
1262         xBytesToStoreMessageLength = 0;
1263     }
1264
1265     /* True if the available space equals zero. */
1266     if( xStreamBufferSpacesAvailable( xStreamBuffer ) <= xBytesToStoreMessageLength )
1267     {
1268         xReturn = pdTRUE;
1269     }
1270     else
1271     {
1272         xReturn = pdFALSE;
1273     }
1274
1275     traceRETURN_xStreamBufferIsFull( xReturn );
1276
1277     return xReturn;
1278 }
1279 /*-----------------------------------------------------------*/
1280
1281 BaseType_t xStreamBufferSendCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1282                                               BaseType_t * pxHigherPriorityTaskWoken )
1283 {
1284     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1285     BaseType_t xReturn;
1286     UBaseType_t uxSavedInterruptStatus;
1287
1288     traceENTER_xStreamBufferSendCompletedFromISR( xStreamBuffer, pxHigherPriorityTaskWoken );
1289
1290     configASSERT( pxStreamBuffer );
1291
1292     uxSavedInterruptStatus = taskENTER_CRITICAL_FROM_ISR();
1293     {
1294         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )
1295         {
1296             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive,
1297                                          ( uint32_t ) 0,
1298                                          eNoAction,
1299                                          pxHigherPriorityTaskWoken );
1300             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;
1301             xReturn = pdTRUE;
1302         }
1303         else
1304         {
1305             xReturn = pdFALSE;
1306         }
1307     }
1308     taskEXIT_CRITICAL_FROM_ISR( uxSavedInterruptStatus );
1309
1310     traceRETURN_xStreamBufferSendCompletedFromISR( xReturn );
1311
1312     return xReturn;
1313 }
1314 /*-----------------------------------------------------------*/
1315
1316 BaseType_t xStreamBufferReceiveCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1317                                                  BaseType_t * pxHigherPriorityTaskWoken )
1318 {
1319     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1320     BaseType_t xReturn;
1321     UBaseType_t uxSavedInterruptStatus;
1322
1323     traceENTER_xStreamBufferReceiveCompletedFromISR( xStreamBuffer, pxHigherPriorityTaskWoken );
1324
1325     configASSERT( pxStreamBuffer );
1326
1327     uxSavedInterruptStatus = taskENTER_CRITICAL_FROM_ISR();
1328     {
1329         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )
1330         {
1331             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend,
1332                                          ( uint32_t ) 0,
1333                                          eNoAction,
1334                                          pxHigherPriorityTaskWoken );
1335             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;
1336             xReturn = pdTRUE;
1337         }
1338         else
1339         {
1340             xReturn = pdFALSE;
1341         }
1342     }
1343     taskEXIT_CRITICAL_FROM_ISR( uxSavedInterruptStatus );
1344
1345     traceRETURN_xStreamBufferReceiveCompletedFromISR( xReturn );
1346
1347     return xReturn;
1348 }
1349 /*-----------------------------------------------------------*/
1350
1351 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
1352                                      const uint8_t * pucData,
1353                                      size_t xCount,
1354                                      size_t xHead )
1355 {
1356     size_t xFirstLength;
1357
1358     configASSERT( xCount > ( size_t ) 0 );
1359
1360     /* Calculate the number of bytes that can be added in the first write -
1361      * which may be less than the total number of bytes that need to be added if
1362      * the buffer will wrap back to the beginning. */
1363     xFirstLength = configMIN( pxStreamBuffer->xLength - xHead, xCount );
1364
1365     /* Write as many bytes as can be written in the first write. */
1366     configASSERT( ( xHead + xFirstLength ) <= pxStreamBuffer->xLength );
1367     ( void ) memcpy( ( void * ) ( &( pxStreamBuffer->pucBuffer[ xHead ] ) ), ( const void * ) pucData, xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1368
1369     /* If the number of bytes written was less than the number that could be
1370      * written in the first write... */
1371     if( xCount > xFirstLength )
1372     {
1373         /* ...then write the remaining bytes to the start of the buffer. */
1374         configASSERT( ( xCount - xFirstLength ) <= pxStreamBuffer->xLength );
1375         ( void ) memcpy( ( void * ) pxStreamBuffer->pucBuffer, ( const void * ) &( pucData[ xFirstLength ] ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1376     }
1377     else
1378     {
1379         mtCOVERAGE_TEST_MARKER();
1380     }
1381
1382     xHead += xCount;
1383
1384     if( xHead >= pxStreamBuffer->xLength )
1385     {
1386         xHead -= pxStreamBuffer->xLength;
1387     }
1388     else
1389     {
1390         mtCOVERAGE_TEST_MARKER();
1391     }
1392
1393     return xHead;
1394 }
1395 /*-----------------------------------------------------------*/
1396
1397 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
1398                                       uint8_t * pucData,
1399                                       size_t xCount,
1400                                       size_t xTail )
1401 {
1402     size_t xFirstLength;
1403
1404     configASSERT( xCount != ( size_t ) 0 );
1405
1406     /* Calculate the number of bytes that can be read - which may be
1407      * less than the number wanted if the data wraps around to the start of
1408      * the buffer. */
1409     xFirstLength = configMIN( pxStreamBuffer->xLength - xTail, xCount );
1410
1411     /* Obtain the number of bytes it is possible to obtain in the first
1412      * read.  Asserts check bounds of read and write. */
1413     configASSERT( xFirstLength <= xCount );
1414     configASSERT( ( xTail + xFirstLength ) <= pxStreamBuffer->xLength );
1415     ( void ) memcpy( ( void * ) pucData, ( const void * ) &( pxStreamBuffer->pucBuffer[ xTail ] ), xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1416
1417     /* If the total number of wanted bytes is greater than the number
1418      * that could be read in the first read... */
1419     if( xCount > xFirstLength )
1420     {
1421         /* ...then read the remaining bytes from the start of the buffer. */
1422         ( void ) memcpy( ( void * ) &( pucData[ xFirstLength ] ), ( void * ) ( pxStreamBuffer->pucBuffer ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1423     }
1424     else
1425     {
1426         mtCOVERAGE_TEST_MARKER();
1427     }
1428
1429     /* Move the tail pointer to effectively remove the data read from the buffer. */
1430     xTail += xCount;
1431
1432     if( xTail >= pxStreamBuffer->xLength )
1433     {
1434         xTail -= pxStreamBuffer->xLength;
1435     }
1436
1437     return xTail;
1438 }
1439 /*-----------------------------------------------------------*/
1440
1441 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer )
1442 {
1443 /* Returns the distance between xTail and xHead. */
1444     size_t xCount;
1445
1446     xCount = pxStreamBuffer->xLength + pxStreamBuffer->xHead;
1447     xCount -= pxStreamBuffer->xTail;
1448
1449     if( xCount >= pxStreamBuffer->xLength )
1450     {
1451         xCount -= pxStreamBuffer->xLength;
1452     }
1453     else
1454     {
1455         mtCOVERAGE_TEST_MARKER();
1456     }
1457
1458     return xCount;
1459 }
1460 /*-----------------------------------------------------------*/
1461
1462 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
1463                                           uint8_t * const pucBuffer,
1464                                           size_t xBufferSizeBytes,
1465                                           size_t xTriggerLevelBytes,
1466                                           uint8_t ucFlags,
1467                                           StreamBufferCallbackFunction_t pxSendCompletedCallback,
1468                                           StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
1469 {
1470     /* Assert here is deliberately writing to the entire buffer to ensure it can
1471      * be written to without generating exceptions, and is setting the buffer to a
1472      * known value to assist in development/debugging. */
1473     #if ( configASSERT_DEFINED == 1 )
1474     {
1475         /* The value written just has to be identifiable when looking at the
1476          * memory.  Don't use 0xA5 as that is the stack fill value and could
1477          * result in confusion as to what is actually being observed. */
1478     #define STREAM_BUFFER_BUFFER_WRITE_VALUE    ( 0x55 )
1479         configASSERT( memset( pucBuffer, ( int ) STREAM_BUFFER_BUFFER_WRITE_VALUE, xBufferSizeBytes ) == pucBuffer );
1480     }
1481     #endif
1482
1483     ( void ) memset( ( void * ) pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) ); /*lint !e9087 memset() requires void *. */
1484     pxStreamBuffer->pucBuffer = pucBuffer;
1485     pxStreamBuffer->xLength = xBufferSizeBytes;
1486     pxStreamBuffer->xTriggerLevelBytes = xTriggerLevelBytes;
1487     pxStreamBuffer->ucFlags = ucFlags;
1488     #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
1489     {
1490         pxStreamBuffer->pxSendCompletedCallback = pxSendCompletedCallback;
1491         pxStreamBuffer->pxReceiveCompletedCallback = pxReceiveCompletedCallback;
1492     }
1493     #else
1494     {
1495         ( void ) pxSendCompletedCallback;
1496         ( void ) pxReceiveCompletedCallback;
1497     }
1498     #endif
1499 }
1500
1501 #if ( configUSE_TRACE_FACILITY == 1 )
1502
1503     UBaseType_t uxStreamBufferGetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer )
1504     {
1505         traceENTER_uxStreamBufferGetStreamBufferNumber( xStreamBuffer );
1506
1507         traceRETURN_uxStreamBufferGetStreamBufferNumber( xStreamBuffer->uxStreamBufferNumber );
1508
1509         return xStreamBuffer->uxStreamBufferNumber;
1510     }
1511
1512 #endif /* configUSE_TRACE_FACILITY */
1513 /*-----------------------------------------------------------*/
1514
1515 #if ( configUSE_TRACE_FACILITY == 1 )
1516
1517     void vStreamBufferSetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer,
1518                                              UBaseType_t uxStreamBufferNumber )
1519     {
1520         traceENTER_vStreamBufferSetStreamBufferNumber( xStreamBuffer, uxStreamBufferNumber );
1521
1522         xStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
1523
1524         traceRETURN_vStreamBufferSetStreamBufferNumber();
1525     }
1526
1527 #endif /* configUSE_TRACE_FACILITY */
1528 /*-----------------------------------------------------------*/
1529
1530 #if ( configUSE_TRACE_FACILITY == 1 )
1531
1532     uint8_t ucStreamBufferGetStreamBufferType( StreamBufferHandle_t xStreamBuffer )
1533     {
1534         traceENTER_ucStreamBufferGetStreamBufferType( xStreamBuffer );
1535
1536         traceRETURN_ucStreamBufferGetStreamBufferType( ( uint8_t ) ( xStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) );
1537
1538         return( ( uint8_t ) ( xStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) );
1539     }
1540
1541 #endif /* configUSE_TRACE_FACILITY */
1542 /*-----------------------------------------------------------*/