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 <stdint.h>
  31 #include <string.h>
  32
  33 /* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
  34  * all the API functions to use the MPU wrappers.  That should only be done when
  35  * task.h is included from an application file. */
  36 #define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
  37
  38 /* FreeRTOS includes. */
  39 #include "FreeRTOS.h"
  40 #include "task.h"
  41 #include "stream_buffer.h"
  42
  43 #if ( configUSE_TASK_NOTIFICATIONS != 1 )
  44     #error configUSE_TASK_NOTIFICATIONS must be set to 1 to build stream_buffer.c
  45 #endif
  46
  47 #if ( INCLUDE_xTaskGetCurrentTaskHandle != 1 )
  48     #error INCLUDE_xTaskGetCurrentTaskHandle must be set to 1 to build stream_buffer.c
  49 #endif
  50
  51 /* Lint e961, e9021 and e750 are suppressed as a MISRA exception justified
  52  * because the MPU ports require MPU_WRAPPERS_INCLUDED_FROM_API_FILE to be defined
  53  * for the header files above, but not in this file, in order to generate the
  54  * correct privileged Vs unprivileged linkage and placement. */
  55 #undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE /*lint !e961 !e750 !e9021. */
  56
  57 /* If the user has not provided application specific Rx notification macros,
  58  * or #defined the notification macros away, then provide default implementations
  59  * that uses task notifications. */
  60 /*lint -save -e9026 Function like macros allowed and needed here so they can be overridden. */
  61 #ifndef sbRECEIVE_COMPLETED
  62     #define sbRECEIVE_COMPLETED( pxStreamBuffer )                         \
  63     vTaskSuspendAll();                                                    \
  64     {                                                                     \
  65         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )              \
  66         {                                                                 \
  67             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToSend, \
  68                                   ( uint32_t ) 0,                         \
  69                                   eNoAction );                            \
  70             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                \
  71         }                                                                 \
  72     }                                                                     \
  73     ( void ) xTaskResumeAll()
  74 #endif /* sbRECEIVE_COMPLETED */
  75
  76 /* If user has provided a per-instance receive complete callback, then
  77  * invoke the callback else use the receive complete macro which is provided by default for all instances.
  78  */
  79 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
  80     #define prvRECEIVE_COMPLETED( pxStreamBuffer )                                               \
  81     {                                                                                            \
  82         if( ( pxStreamBuffer )->pxReceiveCompletedCallback != NULL )                             \
  83         {                                                                                        \
  84             ( pxStreamBuffer )->pxReceiveCompletedCallback( ( pxStreamBuffer ), pdFALSE, NULL ); \
  85         }                                                                                        \
  86         else                                                                                     \
  87         {                                                                                        \
  88             sbRECEIVE_COMPLETED( ( pxStreamBuffer ) );                                           \
  89         }                                                                                        \
  90     }
  91 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
  92     #define prvRECEIVE_COMPLETED( pxStreamBuffer )    sbRECEIVE_COMPLETED( ( pxStreamBuffer ) )
  93 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
  94
  95 #ifndef sbRECEIVE_COMPLETED_FROM_ISR
  96     #define sbRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer,                            \
  97                                           pxHigherPriorityTaskWoken )                \
  98     do {                                                                             \
  99         UBaseType_t uxSavedInterruptStatus;                                          \
 100                                                                                      \
 101         uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();                  \
 102         {                                                                            \
 103             if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )                     \
 104             {                                                                        \
 105                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend, \
 106                                              ( uint32_t ) 0,                         \
 107                                              eNoAction,                              \
 108                                              ( pxHigherPriorityTaskWoken ) );        \
 109                 ( pxStreamBuffer )->xTaskWaitingToSend = NULL;                       \
 110             }                                                                        \
 111         }                                                                            \
 112         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );                 \
 113     } while( 0 )
 114 #endif /* sbRECEIVE_COMPLETED_FROM_ISR */
 115
 116 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 117     #define prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer,                                                               \
 118                                            pxHigherPriorityTaskWoken )                                                   \
 119     {                                                                                                                    \
 120         if( ( pxStreamBuffer )->pxReceiveCompletedCallback != NULL )                                                     \
 121         {                                                                                                                \
 122             ( pxStreamBuffer )->pxReceiveCompletedCallback( ( pxStreamBuffer ), pdTRUE, ( pxHigherPriorityTaskWoken ) ); \
 123         }                                                                                                                \
 124         else                                                                                                             \
 125         {                                                                                                                \
 126             sbRECEIVE_COMPLETED_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) );                           \
 127         }                                                                                                                \
 128     }
 129 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 130     #define prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken ) \
 131     sbRECEIVE_COMPLETED_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) )
 132 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 133
 134 /* If the user has not provided an application specific Tx notification macro,
 135  * or #defined the notification macro away, then provide a default
 136  * implementation that uses task notifications.
 137  */
 138 #ifndef sbSEND_COMPLETED
 139     #define sbSEND_COMPLETED( pxStreamBuffer )                               \
 140     vTaskSuspendAll();                                                       \
 141     {                                                                        \
 142         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )              \
 143         {                                                                    \
 144             ( void ) xTaskNotify( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 145                                   ( uint32_t ) 0,                            \
 146                                   eNoAction );                               \
 147             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                \
 148         }                                                                    \
 149     }                                                                        \
 150     ( void ) xTaskResumeAll()
 151 #endif /* sbSEND_COMPLETED */
 152
 153 /* If user has provided a per-instance send completed callback, then
 154  * invoke the callback else use the send complete macro which is provided by default for all instances.
 155  */
 156 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 157     #define prvSEND_COMPLETED( pxStreamBuffer )                                           \
 158     do {                                                                                  \
 159         if( ( pxStreamBuffer )->pxSendCompletedCallback != NULL )                         \
 160         {                                                                                 \
 161             pxStreamBuffer->pxSendCompletedCallback( ( pxStreamBuffer ), pdFALSE, NULL ); \
 162         }                                                                                 \
 163         else                                                                              \
 164         {                                                                                 \
 165             sbSEND_COMPLETED( ( pxStreamBuffer ) );                                       \
 166         }                                                                                 \
 167     } while( 0 )
 168 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 169     #define prvSEND_COMPLETED( pxStreamBuffer )    sbSEND_COMPLETED( ( pxStreamBuffer ) )
 170 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 171
 172
 173 #ifndef sbSEND_COMPLETE_FROM_ISR
 174     #define sbSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken )       \
 175     do {                                                                                \
 176         UBaseType_t uxSavedInterruptStatus;                                             \
 177                                                                                         \
 178         uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();                     \
 179         {                                                                               \
 180             if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )                     \
 181             {                                                                           \
 182                 ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive, \
 183                                              ( uint32_t ) 0,                            \
 184                                              eNoAction,                                 \
 185                                              ( pxHigherPriorityTaskWoken ) );           \
 186                 ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;                       \
 187             }                                                                           \
 188         }                                                                               \
 189         portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );                    \
 190     } while( 0 )
 191 #endif /* sbSEND_COMPLETE_FROM_ISR */
 192
 193
 194 #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 195     #define prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken )                                    \
 196     do {                                                                                                              \
 197         if( ( pxStreamBuffer )->pxSendCompletedCallback != NULL )                                                     \
 198         {                                                                                                             \
 199             ( pxStreamBuffer )->pxSendCompletedCallback( ( pxStreamBuffer ), pdTRUE, ( pxHigherPriorityTaskWoken ) ); \
 200         }                                                                                                             \
 201         else                                                                                                          \
 202         {                                                                                                             \
 203             sbSEND_COMPLETE_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) );                            \
 204         }                                                                                                             \
 205     } while( 0 )
 206 #else /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 207     #define prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken ) \
 208     sbSEND_COMPLETE_FROM_ISR( ( pxStreamBuffer ), ( pxHigherPriorityTaskWoken ) )
 209 #endif /* if ( configUSE_SB_COMPLETED_CALLBACK == 1 ) */
 210
 211 /*lint -restore (9026) */
 212
 213 /* The number of bytes used to hold the length of a message in the buffer. */
 214 #define sbBYTES_TO_STORE_MESSAGE_LENGTH    ( sizeof( configMESSAGE_BUFFER_LENGTH_TYPE ) )
 215
 216 /* Bits stored in the ucFlags field of the stream buffer. */
 217 #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. */
 218 #define sbFLAGS_IS_STATICALLY_ALLOCATED    ( ( uint8_t ) 2 ) /* Set if the stream buffer was created using statically allocated memory. */
 219
 220 /*-----------------------------------------------------------*/
 221
 222 /* Structure that hold state information on the buffer. */
 223 typedef struct StreamBufferDef_t                 /*lint !e9058 Style convention uses tag. */
 224 {
 225     volatile size_t xTail;                       /* Index to the next item to read within the buffer. */
 226     volatile size_t xHead;                       /* Index to the next item to write within the buffer. */
 227     size_t xLength;                              /* The length of the buffer pointed to by pucBuffer. */
 228     size_t xTriggerLevelBytes;                   /* The number of bytes that must be in the stream buffer before a task that is waiting for data is unblocked. */
 229     volatile TaskHandle_t xTaskWaitingToReceive; /* Holds the handle of a task waiting for data, or NULL if no tasks are waiting. */
 230     volatile TaskHandle_t xTaskWaitingToSend;    /* Holds the handle of a task waiting to send data to a message buffer that is full. */
 231     uint8_t * pucBuffer;                         /* Points to the buffer itself - that is - the RAM that stores the data passed through the buffer. */
 232     uint8_t ucFlags;
 233
 234     #if ( configUSE_TRACE_FACILITY == 1 )
 235         UBaseType_t uxStreamBufferNumber; /* Used for tracing purposes. */
 236     #endif
 237
 238     #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 239         StreamBufferCallbackFunction_t pxSendCompletedCallback;    /* Optional callback called on send complete. sbSEND_COMPLETED is called if this is NULL. */
 240         StreamBufferCallbackFunction_t pxReceiveCompletedCallback; /* Optional callback called on receive complete.  sbRECEIVE_COMPLETED is called if this is NULL. */
 241     #endif
 242 } StreamBuffer_t;
 243
 244 /*
 245  * The number of bytes available to be read from the buffer.
 246  */
 247 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer ) PRIVILEGED_FUNCTION;
 248
 249 /*
 250  * Add xCount bytes from pucData into the pxStreamBuffer's data storage area.
 251  * This function does not update the buffer's xHead pointer, so multiple writes
 252  * may be chained together "atomically". This is useful for Message Buffers where
 253  * the length and data bytes are written in two separate chunks, and we don't want
 254  * the reader to see the buffer as having grown until after all data is copied over.
 255  * This function takes a custom xHead value to indicate where to write to (necessary
 256  * for chaining) and returns the the resulting xHead position.
 257  * To mark the write as complete, manually set the buffer's xHead field with the
 258  * returned xHead from this function.
 259  */
 260 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
 261                                      const uint8_t * pucData,
 262                                      size_t xCount,
 263                                      size_t xHead ) PRIVILEGED_FUNCTION;
 264
 265 /*
 266  * If the stream buffer is being used as a message buffer, then reads an entire
 267  * message out of the buffer.  If the stream buffer is being used as a stream
 268  * buffer then read as many bytes as possible from the buffer.
 269  * prvReadBytesFromBuffer() is called to actually extract the bytes from the
 270  * buffer's data storage area.
 271  */
 272 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
 273                                         void * pvRxData,
 274                                         size_t xBufferLengthBytes,
 275                                         size_t xBytesAvailable ) PRIVILEGED_FUNCTION;
 276
 277 /*
 278  * If the stream buffer is being used as a message buffer, then writes an entire
 279  * message to the buffer.  If the stream buffer is being used as a stream
 280  * buffer then write as many bytes as possible to the buffer.
 281  * prvWriteBytestoBuffer() is called to actually send the bytes to the buffer's
 282  * data storage area.
 283  */
 284 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 285                                        const void * pvTxData,
 286                                        size_t xDataLengthBytes,
 287                                        size_t xSpace,
 288                                        size_t xRequiredSpace ) PRIVILEGED_FUNCTION;
 289
 290 /*
 291  * Copies xCount bytes from the pxStreamBuffer's data storage area to pucData.
 292  * This function does not update the buffer's xTail pointer, so multiple reads
 293  * may be chained together "atomically". This is useful for Message Buffers where
 294  * the length and data bytes are read in two separate chunks, and we don't want
 295  * the writer to see the buffer as having more free space until after all data is
 296  * copied over, especially if we have to abort the read due to insufficient receiving space.
 297  * This function takes a custom xTail value to indicate where to read from (necessary
 298  * for chaining) and returns the the resulting xTail position.
 299  * To mark the read as complete, manually set the buffer's xTail field with the
 300  * returned xTail from this function.
 301  */
 302 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
 303                                       uint8_t * pucData,
 304                                       size_t xCount,
 305                                       size_t xTail ) PRIVILEGED_FUNCTION;
 306
 307 /*
 308  * Called by both pxStreamBufferCreate() and pxStreamBufferCreateStatic() to
 309  * initialise the members of the newly created stream buffer structure.
 310  */
 311 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
 312                                           uint8_t * const pucBuffer,
 313                                           size_t xBufferSizeBytes,
 314                                           size_t xTriggerLevelBytes,
 315                                           uint8_t ucFlags,
 316                                           StreamBufferCallbackFunction_t pxSendCompletedCallback,
 317                                           StreamBufferCallbackFunction_t pxReceiveCompletedCallback ) PRIVILEGED_FUNCTION;
 318
 319 /*-----------------------------------------------------------*/
 320 #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 321     StreamBufferHandle_t xStreamBufferGenericCreate( size_t xBufferSizeBytes,
 322                                                      size_t xTriggerLevelBytes,
 323                                                      BaseType_t xIsMessageBuffer,
 324                                                      StreamBufferCallbackFunction_t pxSendCompletedCallback,
 325                                                      StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
 326     {
 327         void * pvAllocatedMemory;
 328         uint8_t ucFlags;
 329
 330         /* In case the stream buffer is going to be used as a message buffer
 331          * (that is, it will hold discrete messages with a little meta data that
 332          * says how big the next message is) check the buffer will be large enough
 333          * to hold at least one message. */
 334         if( xIsMessageBuffer == pdTRUE )
 335         {
 336             /* Is a message buffer but not statically allocated. */
 337             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER;
 338             configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 339         }
 340         else
 341         {
 342             /* Not a message buffer and not statically allocated. */
 343             ucFlags = 0;
 344             configASSERT( xBufferSizeBytes > 0 );
 345         }
 346
 347         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 348
 349         /* A trigger level of 0 would cause a waiting task to unblock even when
 350          * the buffer was empty. */
 351         if( xTriggerLevelBytes == ( size_t ) 0 )
 352         {
 353             xTriggerLevelBytes = ( size_t ) 1;
 354         }
 355
 356         /* A stream buffer requires a StreamBuffer_t structure and a buffer.
 357          * Both are allocated in a single call to pvPortMalloc().  The
 358          * StreamBuffer_t structure is placed at the start of the allocated memory
 359          * and the buffer follows immediately after.  The requested size is
 360          * incremented so the free space is returned as the user would expect -
 361          * this is a quirk of the implementation that means otherwise the free
 362          * space would be reported as one byte smaller than would be logically
 363          * expected. */
 364         if( xBufferSizeBytes < ( xBufferSizeBytes + 1 + sizeof( StreamBuffer_t ) ) )
 365         {
 366             xBufferSizeBytes++;
 367             pvAllocatedMemory = pvPortMalloc( xBufferSizeBytes + sizeof( StreamBuffer_t ) );
 368         }
 369         else
 370         {
 371             pvAllocatedMemory = NULL;
 372         }
 373
 374         if( pvAllocatedMemory != NULL )
 375         {
 376             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. */
 377                                           ( ( 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. */
 378                                           xBufferSizeBytes,
 379                                           xTriggerLevelBytes,
 380                                           ucFlags,
 381                                           pxSendCompletedCallback,
 382                                           pxReceiveCompletedCallback );
 383
 384             traceSTREAM_BUFFER_CREATE( ( ( StreamBuffer_t * ) pvAllocatedMemory ), xIsMessageBuffer );
 385         }
 386         else
 387         {
 388             traceSTREAM_BUFFER_CREATE_FAILED( xIsMessageBuffer );
 389         }
 390
 391         return ( StreamBufferHandle_t ) pvAllocatedMemory; /*lint !e9087 !e826 Safe cast as allocated memory is aligned. */
 392     }
 393 #endif /* configSUPPORT_DYNAMIC_ALLOCATION */
 394 /*-----------------------------------------------------------*/
 395
 396 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
 397
 398     StreamBufferHandle_t xStreamBufferGenericCreateStatic( size_t xBufferSizeBytes,
 399                                                            size_t xTriggerLevelBytes,
 400                                                            BaseType_t xIsMessageBuffer,
 401                                                            uint8_t * const pucStreamBufferStorageArea,
 402                                                            StaticStreamBuffer_t * const pxStaticStreamBuffer,
 403                                                            StreamBufferCallbackFunction_t pxSendCompletedCallback,
 404                                                            StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
 405     {
 406         StreamBuffer_t * const pxStreamBuffer = ( StreamBuffer_t * ) pxStaticStreamBuffer; /*lint !e740 !e9087 Safe cast as StaticStreamBuffer_t is opaque Streambuffer_t. */
 407         StreamBufferHandle_t xReturn;
 408         uint8_t ucFlags;
 409
 410         configASSERT( pucStreamBufferStorageArea );
 411         configASSERT( pxStaticStreamBuffer );
 412         configASSERT( xTriggerLevelBytes <= xBufferSizeBytes );
 413
 414         /* A trigger level of 0 would cause a waiting task to unblock even when
 415          * the buffer was empty. */
 416         if( xTriggerLevelBytes == ( size_t ) 0 )
 417         {
 418             xTriggerLevelBytes = ( size_t ) 1;
 419         }
 420
 421         if( xIsMessageBuffer != pdFALSE )
 422         {
 423             /* Statically allocated message buffer. */
 424             ucFlags = sbFLAGS_IS_MESSAGE_BUFFER | sbFLAGS_IS_STATICALLY_ALLOCATED;
 425         }
 426         else
 427         {
 428             /* Statically allocated stream buffer. */
 429             ucFlags = sbFLAGS_IS_STATICALLY_ALLOCATED;
 430         }
 431
 432         /* In case the stream buffer is going to be used as a message buffer
 433          * (that is, it will hold discrete messages with a little meta data that
 434          * says how big the next message is) check the buffer will be large enough
 435          * to hold at least one message. */
 436         configASSERT( xBufferSizeBytes > sbBYTES_TO_STORE_MESSAGE_LENGTH );
 437
 438         #if ( configASSERT_DEFINED == 1 )
 439
 440             /* Sanity check that the size of the structure used to declare a
 441              * variable of type StaticStreamBuffer_t equals the size of the real
 442              * message buffer structure. */
 443             configASSERT( sizeof( StaticStreamBuffer_t ) == sizeof( StreamBuffer_t ) );
 444         #endif /* configASSERT_DEFINED */
 445
 446         if( ( pucStreamBufferStorageArea != NULL ) && ( pxStaticStreamBuffer != NULL ) )
 447         {
 448             prvInitialiseNewStreamBuffer( pxStreamBuffer,
 449                                           pucStreamBufferStorageArea,
 450                                           xBufferSizeBytes,
 451                                           xTriggerLevelBytes,
 452                                           ucFlags,
 453                                           pxSendCompletedCallback,
 454                                           pxReceiveCompletedCallback );
 455
 456             /* Remember this was statically allocated in case it is ever deleted
 457              * again. */
 458             pxStreamBuffer->ucFlags |= sbFLAGS_IS_STATICALLY_ALLOCATED;
 459
 460             traceSTREAM_BUFFER_CREATE( pxStreamBuffer, xIsMessageBuffer );
 461
 462             xReturn = ( StreamBufferHandle_t ) pxStaticStreamBuffer; /*lint !e9087 Data hiding requires cast to opaque type. */
 463         }
 464         else
 465         {
 466             xReturn = NULL;
 467             traceSTREAM_BUFFER_CREATE_STATIC_FAILED( xReturn, xIsMessageBuffer );
 468         }
 469
 470         return xReturn;
 471     }
 472 #endif /* ( configSUPPORT_STATIC_ALLOCATION == 1 ) */
 473 /*-----------------------------------------------------------*/
 474
 475 #if ( configSUPPORT_STATIC_ALLOCATION == 1 )
 476     BaseType_t xStreamBufferGetStaticBuffers( StreamBufferHandle_t xStreamBuffer,
 477                                               uint8_t ** ppucStreamBufferStorageArea,
 478                                               StaticStreamBuffer_t ** ppxStaticStreamBuffer )
 479     {
 480         BaseType_t xReturn;
 481         const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 482
 483         configASSERT( pxStreamBuffer );
 484         configASSERT( ppucStreamBufferStorageArea );
 485         configASSERT( ppxStaticStreamBuffer );
 486
 487         if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) != ( uint8_t ) 0 )
 488         {
 489             *ppucStreamBufferStorageArea = pxStreamBuffer->pucBuffer;
 490             *ppxStaticStreamBuffer = ( StaticStreamBuffer_t * ) pxStreamBuffer;
 491             xReturn = pdTRUE;
 492         }
 493         else
 494         {
 495             xReturn = pdFALSE;
 496         }
 497
 498         return xReturn;
 499     }
 500 #endif /* configSUPPORT_STATIC_ALLOCATION */
 501 /*-----------------------------------------------------------*/
 502
 503 void vStreamBufferDelete( StreamBufferHandle_t xStreamBuffer )
 504 {
 505     StreamBuffer_t * pxStreamBuffer = xStreamBuffer;
 506
 507     configASSERT( pxStreamBuffer );
 508
 509     traceSTREAM_BUFFER_DELETE( xStreamBuffer );
 510
 511     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_STATICALLY_ALLOCATED ) == ( uint8_t ) pdFALSE )
 512     {
 513         #if ( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
 514         {
 515             /* Both the structure and the buffer were allocated using a single call
 516             * to pvPortMalloc(), hence only one call to vPortFree() is required. */
 517             vPortFree( ( void * ) pxStreamBuffer ); /*lint !e9087 Standard free() semantics require void *, plus pxStreamBuffer was allocated by pvPortMalloc(). */
 518         }
 519         #else
 520         {
 521             /* Should not be possible to get here, ucFlags must be corrupt.
 522              * Force an assert. */
 523             configASSERT( xStreamBuffer == ( StreamBufferHandle_t ) ~0 );
 524         }
 525         #endif
 526     }
 527     else
 528     {
 529         /* The structure and buffer were not allocated dynamically and cannot be
 530          * freed - just scrub the structure so future use will assert. */
 531         ( void ) memset( pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) );
 532     }
 533 }
 534 /*-----------------------------------------------------------*/
 535
 536 BaseType_t xStreamBufferReset( StreamBufferHandle_t xStreamBuffer )
 537 {
 538     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 539     BaseType_t xReturn = pdFAIL;
 540     StreamBufferCallbackFunction_t pxSendCallback = NULL, pxReceiveCallback = NULL;
 541
 542     #if ( configUSE_TRACE_FACILITY == 1 )
 543         UBaseType_t uxStreamBufferNumber;
 544     #endif
 545
 546     configASSERT( pxStreamBuffer );
 547
 548     #if ( configUSE_TRACE_FACILITY == 1 )
 549     {
 550         /* Store the stream buffer number so it can be restored after the
 551          * reset. */
 552         uxStreamBufferNumber = pxStreamBuffer->uxStreamBufferNumber;
 553     }
 554     #endif
 555
 556     /* Can only reset a message buffer if there are no tasks blocked on it. */
 557     taskENTER_CRITICAL();
 558     {
 559         if( ( pxStreamBuffer->xTaskWaitingToReceive == NULL ) && ( pxStreamBuffer->xTaskWaitingToSend == NULL ) )
 560         {
 561             #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
 562             {
 563                 pxSendCallback = pxStreamBuffer->pxSendCompletedCallback;
 564                 pxReceiveCallback = pxStreamBuffer->pxReceiveCompletedCallback;
 565             }
 566             #endif
 567
 568             prvInitialiseNewStreamBuffer( pxStreamBuffer,
 569                                           pxStreamBuffer->pucBuffer,
 570                                           pxStreamBuffer->xLength,
 571                                           pxStreamBuffer->xTriggerLevelBytes,
 572                                           pxStreamBuffer->ucFlags,
 573                                           pxSendCallback,
 574                                           pxReceiveCallback );
 575
 576             #if ( configUSE_TRACE_FACILITY == 1 )
 577             {
 578                 pxStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
 579             }
 580             #endif
 581
 582             traceSTREAM_BUFFER_RESET( xStreamBuffer );
 583
 584             xReturn = pdPASS;
 585         }
 586     }
 587     taskEXIT_CRITICAL();
 588
 589     return xReturn;
 590 }
 591 /*-----------------------------------------------------------*/
 592
 593 BaseType_t xStreamBufferSetTriggerLevel( StreamBufferHandle_t xStreamBuffer,
 594                                          size_t xTriggerLevel )
 595 {
 596     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 597     BaseType_t xReturn;
 598
 599     configASSERT( pxStreamBuffer );
 600
 601     /* It is not valid for the trigger level to be 0. */
 602     if( xTriggerLevel == ( size_t ) 0 )
 603     {
 604         xTriggerLevel = ( size_t ) 1;
 605     }
 606
 607     /* The trigger level is the number of bytes that must be in the stream
 608      * buffer before a task that is waiting for data is unblocked. */
 609     if( xTriggerLevel < pxStreamBuffer->xLength )
 610     {
 611         pxStreamBuffer->xTriggerLevelBytes = xTriggerLevel;
 612         xReturn = pdPASS;
 613     }
 614     else
 615     {
 616         xReturn = pdFALSE;
 617     }
 618
 619     return xReturn;
 620 }
 621 /*-----------------------------------------------------------*/
 622
 623 size_t xStreamBufferSpacesAvailable( StreamBufferHandle_t xStreamBuffer )
 624 {
 625     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 626     size_t xSpace;
 627     size_t xOriginalTail;
 628
 629     configASSERT( pxStreamBuffer );
 630
 631     /* The code below reads xTail and then xHead.  This is safe if the stream
 632      * buffer is updated once between the two reads - but not if the stream buffer
 633      * is updated more than once between the two reads - hence the loop. */
 634     do
 635     {
 636         xOriginalTail = pxStreamBuffer->xTail;
 637         xSpace = pxStreamBuffer->xLength + pxStreamBuffer->xTail;
 638         xSpace -= pxStreamBuffer->xHead;
 639     } while( xOriginalTail != pxStreamBuffer->xTail );
 640
 641     xSpace -= ( size_t ) 1;
 642
 643     if( xSpace >= pxStreamBuffer->xLength )
 644     {
 645         xSpace -= pxStreamBuffer->xLength;
 646     }
 647     else
 648     {
 649         mtCOVERAGE_TEST_MARKER();
 650     }
 651
 652     return xSpace;
 653 }
 654 /*-----------------------------------------------------------*/
 655
 656 size_t xStreamBufferBytesAvailable( StreamBufferHandle_t xStreamBuffer )
 657 {
 658     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 659     size_t xReturn;
 660
 661     configASSERT( pxStreamBuffer );
 662
 663     xReturn = prvBytesInBuffer( pxStreamBuffer );
 664     return xReturn;
 665 }
 666 /*-----------------------------------------------------------*/
 667
 668 size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
 669                           const void * pvTxData,
 670                           size_t xDataLengthBytes,
 671                           TickType_t xTicksToWait )
 672 {
 673     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 674     size_t xReturn, xSpace = 0;
 675     size_t xRequiredSpace = xDataLengthBytes;
 676     TimeOut_t xTimeOut;
 677     size_t xMaxReportedSpace = 0;
 678
 679     configASSERT( pvTxData );
 680     configASSERT( pxStreamBuffer );
 681
 682     /* The maximum amount of space a stream buffer will ever report is its length
 683      * minus 1. */
 684     xMaxReportedSpace = pxStreamBuffer->xLength - ( size_t ) 1;
 685
 686     /* This send function is used to write to both message buffers and stream
 687      * buffers.  If this is a message buffer then the space needed must be
 688      * increased by the amount of bytes needed to store the length of the
 689      * message. */
 690     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 691     {
 692         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 693
 694         /* Overflow? */
 695         configASSERT( xRequiredSpace > xDataLengthBytes );
 696
 697         /* If this is a message buffer then it must be possible to write the
 698          * whole message. */
 699         if( xRequiredSpace > xMaxReportedSpace )
 700         {
 701             /* The message would not fit even if the entire buffer was empty,
 702              * so don't wait for space. */
 703             xTicksToWait = ( TickType_t ) 0;
 704         }
 705         else
 706         {
 707             mtCOVERAGE_TEST_MARKER();
 708         }
 709     }
 710     else
 711     {
 712         /* If this is a stream buffer then it is acceptable to write only part
 713          * of the message to the buffer.  Cap the length to the total length of
 714          * the buffer. */
 715         if( xRequiredSpace > xMaxReportedSpace )
 716         {
 717             xRequiredSpace = xMaxReportedSpace;
 718         }
 719         else
 720         {
 721             mtCOVERAGE_TEST_MARKER();
 722         }
 723     }
 724
 725     if( xTicksToWait != ( TickType_t ) 0 )
 726     {
 727         vTaskSetTimeOutState( &xTimeOut );
 728
 729         do
 730         {
 731             /* Wait until the required number of bytes are free in the message
 732              * buffer. */
 733             taskENTER_CRITICAL();
 734             {
 735                 xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 736
 737                 if( xSpace < xRequiredSpace )
 738                 {
 739                     /* Clear notification state as going to wait for space. */
 740                     ( void ) xTaskNotifyStateClear( NULL );
 741
 742                     /* Should only be one writer. */
 743                     configASSERT( pxStreamBuffer->xTaskWaitingToSend == NULL );
 744                     pxStreamBuffer->xTaskWaitingToSend = xTaskGetCurrentTaskHandle();
 745                 }
 746                 else
 747                 {
 748                     taskEXIT_CRITICAL();
 749                     break;
 750                 }
 751             }
 752             taskEXIT_CRITICAL();
 753
 754             traceBLOCKING_ON_STREAM_BUFFER_SEND( xStreamBuffer );
 755             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
 756             pxStreamBuffer->xTaskWaitingToSend = NULL;
 757         } while( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE );
 758     }
 759     else
 760     {
 761         mtCOVERAGE_TEST_MARKER();
 762     }
 763
 764     if( xSpace == ( size_t ) 0 )
 765     {
 766         xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 767     }
 768     else
 769     {
 770         mtCOVERAGE_TEST_MARKER();
 771     }
 772
 773     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 774
 775     if( xReturn > ( size_t ) 0 )
 776     {
 777         traceSTREAM_BUFFER_SEND( xStreamBuffer, xReturn );
 778
 779         /* Was a task waiting for the data? */
 780         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 781         {
 782             prvSEND_COMPLETED( pxStreamBuffer );
 783         }
 784         else
 785         {
 786             mtCOVERAGE_TEST_MARKER();
 787         }
 788     }
 789     else
 790     {
 791         mtCOVERAGE_TEST_MARKER();
 792         traceSTREAM_BUFFER_SEND_FAILED( xStreamBuffer );
 793     }
 794
 795     return xReturn;
 796 }
 797 /*-----------------------------------------------------------*/
 798
 799 size_t xStreamBufferSendFromISR( StreamBufferHandle_t xStreamBuffer,
 800                                  const void * pvTxData,
 801                                  size_t xDataLengthBytes,
 802                                  BaseType_t * const pxHigherPriorityTaskWoken )
 803 {
 804     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 805     size_t xReturn, xSpace;
 806     size_t xRequiredSpace = xDataLengthBytes;
 807
 808     configASSERT( pvTxData );
 809     configASSERT( pxStreamBuffer );
 810
 811     /* This send function is used to write to both message buffers and stream
 812      * buffers.  If this is a message buffer then the space needed must be
 813      * increased by the amount of bytes needed to store the length of the
 814      * message. */
 815     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 816     {
 817         xRequiredSpace += sbBYTES_TO_STORE_MESSAGE_LENGTH;
 818     }
 819     else
 820     {
 821         mtCOVERAGE_TEST_MARKER();
 822     }
 823
 824     xSpace = xStreamBufferSpacesAvailable( pxStreamBuffer );
 825     xReturn = prvWriteMessageToBuffer( pxStreamBuffer, pvTxData, xDataLengthBytes, xSpace, xRequiredSpace );
 826
 827     if( xReturn > ( size_t ) 0 )
 828     {
 829         /* Was a task waiting for the data? */
 830         if( prvBytesInBuffer( pxStreamBuffer ) >= pxStreamBuffer->xTriggerLevelBytes )
 831         {
 832             prvSEND_COMPLETE_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
 833         }
 834         else
 835         {
 836             mtCOVERAGE_TEST_MARKER();
 837         }
 838     }
 839     else
 840     {
 841         mtCOVERAGE_TEST_MARKER();
 842     }
 843
 844     traceSTREAM_BUFFER_SEND_FROM_ISR( xStreamBuffer, xReturn );
 845
 846     return xReturn;
 847 }
 848 /*-----------------------------------------------------------*/
 849
 850 static size_t prvWriteMessageToBuffer( StreamBuffer_t * const pxStreamBuffer,
 851                                        const void * pvTxData,
 852                                        size_t xDataLengthBytes,
 853                                        size_t xSpace,
 854                                        size_t xRequiredSpace )
 855 {
 856     size_t xNextHead = pxStreamBuffer->xHead;
 857     configMESSAGE_BUFFER_LENGTH_TYPE xMessageLength;
 858
 859     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 860     {
 861         /* This is a message buffer, as opposed to a stream buffer. */
 862
 863         /* Convert xDataLengthBytes to the message length type. */
 864         xMessageLength = ( configMESSAGE_BUFFER_LENGTH_TYPE ) xDataLengthBytes;
 865
 866         /* Ensure the data length given fits within configMESSAGE_BUFFER_LENGTH_TYPE. */
 867         configASSERT( ( size_t ) xMessageLength == xDataLengthBytes );
 868
 869         if( xSpace >= xRequiredSpace )
 870         {
 871             /* There is enough space to write both the message length and the message
 872              * itself into the buffer.  Start by writing the length of the data, the data
 873              * itself will be written later in this function. */
 874             xNextHead = prvWriteBytesToBuffer( pxStreamBuffer, ( const uint8_t * ) &( xMessageLength ), sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextHead );
 875         }
 876         else
 877         {
 878             /* Not enough space, so do not write data to the buffer. */
 879             xDataLengthBytes = 0;
 880         }
 881     }
 882     else
 883     {
 884         /* This is a stream buffer, as opposed to a message buffer, so writing a
 885          * stream of bytes rather than discrete messages.  Plan to write as many
 886          * bytes as possible. */
 887         xDataLengthBytes = configMIN( xDataLengthBytes, xSpace );
 888     }
 889
 890     if( xDataLengthBytes != ( size_t ) 0 )
 891     {
 892         /* Write the data to the buffer. */
 893         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. */
 894     }
 895
 896     return xDataLengthBytes;
 897 }
 898 /*-----------------------------------------------------------*/
 899
 900 size_t xStreamBufferReceive( StreamBufferHandle_t xStreamBuffer,
 901                              void * pvRxData,
 902                              size_t xBufferLengthBytes,
 903                              TickType_t xTicksToWait )
 904 {
 905     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
 906     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
 907
 908     configASSERT( pvRxData );
 909     configASSERT( pxStreamBuffer );
 910
 911     /* This receive function is used by both message buffers, which store
 912      * discrete messages, and stream buffers, which store a continuous stream of
 913      * bytes.  Discrete messages include an additional
 914      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
 915      * message. */
 916     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
 917     {
 918         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
 919     }
 920     else
 921     {
 922         xBytesToStoreMessageLength = 0;
 923     }
 924
 925     if( xTicksToWait != ( TickType_t ) 0 )
 926     {
 927         /* Checking if there is data and clearing the notification state must be
 928          * performed atomically. */
 929         taskENTER_CRITICAL();
 930         {
 931             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 932
 933             /* If this function was invoked by a message buffer read then
 934              * xBytesToStoreMessageLength holds the number of bytes used to hold
 935              * the length of the next discrete message.  If this function was
 936              * invoked by a stream buffer read then xBytesToStoreMessageLength will
 937              * be 0. */
 938             if( xBytesAvailable <= xBytesToStoreMessageLength )
 939             {
 940                 /* Clear notification state as going to wait for data. */
 941                 ( void ) xTaskNotifyStateClear( NULL );
 942
 943                 /* Should only be one reader. */
 944                 configASSERT( pxStreamBuffer->xTaskWaitingToReceive == NULL );
 945                 pxStreamBuffer->xTaskWaitingToReceive = xTaskGetCurrentTaskHandle();
 946             }
 947             else
 948             {
 949                 mtCOVERAGE_TEST_MARKER();
 950             }
 951         }
 952         taskEXIT_CRITICAL();
 953
 954         if( xBytesAvailable <= xBytesToStoreMessageLength )
 955         {
 956             /* Wait for data to be available. */
 957             traceBLOCKING_ON_STREAM_BUFFER_RECEIVE( xStreamBuffer );
 958             ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait );
 959             pxStreamBuffer->xTaskWaitingToReceive = NULL;
 960
 961             /* Recheck the data available after blocking. */
 962             xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 963         }
 964         else
 965         {
 966             mtCOVERAGE_TEST_MARKER();
 967         }
 968     }
 969     else
 970     {
 971         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
 972     }
 973
 974     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
 975      * holds the number of bytes used to store the message length) or a stream of
 976      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
 977      * available must be greater than xBytesToStoreMessageLength to be able to
 978      * read bytes from the buffer. */
 979     if( xBytesAvailable > xBytesToStoreMessageLength )
 980     {
 981         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
 982
 983         /* Was a task waiting for space in the buffer? */
 984         if( xReceivedLength != ( size_t ) 0 )
 985         {
 986             traceSTREAM_BUFFER_RECEIVE( xStreamBuffer, xReceivedLength );
 987             prvRECEIVE_COMPLETED( xStreamBuffer );
 988         }
 989         else
 990         {
 991             mtCOVERAGE_TEST_MARKER();
 992         }
 993     }
 994     else
 995     {
 996         traceSTREAM_BUFFER_RECEIVE_FAILED( xStreamBuffer );
 997         mtCOVERAGE_TEST_MARKER();
 998     }
 999
1000     return xReceivedLength;
1001 }
1002 /*-----------------------------------------------------------*/
1003
1004 size_t xStreamBufferNextMessageLengthBytes( StreamBufferHandle_t xStreamBuffer )
1005 {
1006     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1007     size_t xReturn, xBytesAvailable;
1008     configMESSAGE_BUFFER_LENGTH_TYPE xTempReturn;
1009
1010     configASSERT( pxStreamBuffer );
1011
1012     /* Ensure the stream buffer is being used as a message buffer. */
1013     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1014     {
1015         xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1016
1017         if( xBytesAvailable > sbBYTES_TO_STORE_MESSAGE_LENGTH )
1018         {
1019             /* The number of bytes available is greater than the number of bytes
1020              * required to hold the length of the next message, so another message
1021              * is available. */
1022             ( void ) prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempReturn, sbBYTES_TO_STORE_MESSAGE_LENGTH, pxStreamBuffer->xTail );
1023             xReturn = ( size_t ) xTempReturn;
1024         }
1025         else
1026         {
1027             /* The minimum amount of bytes in a message buffer is
1028              * ( sbBYTES_TO_STORE_MESSAGE_LENGTH + 1 ), so if xBytesAvailable is
1029              * less than sbBYTES_TO_STORE_MESSAGE_LENGTH the only other valid
1030              * value is 0. */
1031             configASSERT( xBytesAvailable == 0 );
1032             xReturn = 0;
1033         }
1034     }
1035     else
1036     {
1037         xReturn = 0;
1038     }
1039
1040     return xReturn;
1041 }
1042 /*-----------------------------------------------------------*/
1043
1044 size_t xStreamBufferReceiveFromISR( StreamBufferHandle_t xStreamBuffer,
1045                                     void * pvRxData,
1046                                     size_t xBufferLengthBytes,
1047                                     BaseType_t * const pxHigherPriorityTaskWoken )
1048 {
1049     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1050     size_t xReceivedLength = 0, xBytesAvailable, xBytesToStoreMessageLength;
1051
1052     configASSERT( pvRxData );
1053     configASSERT( pxStreamBuffer );
1054
1055     /* This receive function is used by both message buffers, which store
1056      * discrete messages, and stream buffers, which store a continuous stream of
1057      * bytes.  Discrete messages include an additional
1058      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the
1059      * message. */
1060     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1061     {
1062         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
1063     }
1064     else
1065     {
1066         xBytesToStoreMessageLength = 0;
1067     }
1068
1069     xBytesAvailable = prvBytesInBuffer( pxStreamBuffer );
1070
1071     /* Whether receiving a discrete message (where xBytesToStoreMessageLength
1072      * holds the number of bytes used to store the message length) or a stream of
1073      * bytes (where xBytesToStoreMessageLength is zero), the number of bytes
1074      * available must be greater than xBytesToStoreMessageLength to be able to
1075      * read bytes from the buffer. */
1076     if( xBytesAvailable > xBytesToStoreMessageLength )
1077     {
1078         xReceivedLength = prvReadMessageFromBuffer( pxStreamBuffer, pvRxData, xBufferLengthBytes, xBytesAvailable );
1079
1080         /* Was a task waiting for space in the buffer? */
1081         if( xReceivedLength != ( size_t ) 0 )
1082         {
1083             prvRECEIVE_COMPLETED_FROM_ISR( pxStreamBuffer, pxHigherPriorityTaskWoken );
1084         }
1085         else
1086         {
1087             mtCOVERAGE_TEST_MARKER();
1088         }
1089     }
1090     else
1091     {
1092         mtCOVERAGE_TEST_MARKER();
1093     }
1094
1095     traceSTREAM_BUFFER_RECEIVE_FROM_ISR( xStreamBuffer, xReceivedLength );
1096
1097     return xReceivedLength;
1098 }
1099 /*-----------------------------------------------------------*/
1100
1101 static size_t prvReadMessageFromBuffer( StreamBuffer_t * pxStreamBuffer,
1102                                         void * pvRxData,
1103                                         size_t xBufferLengthBytes,
1104                                         size_t xBytesAvailable )
1105 {
1106     size_t xCount, xNextMessageLength;
1107     configMESSAGE_BUFFER_LENGTH_TYPE xTempNextMessageLength;
1108     size_t xNextTail = pxStreamBuffer->xTail;
1109
1110     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1111     {
1112         /* A discrete message is being received.  First receive the length
1113          * of the message. */
1114         xNextTail = prvReadBytesFromBuffer( pxStreamBuffer, ( uint8_t * ) &xTempNextMessageLength, sbBYTES_TO_STORE_MESSAGE_LENGTH, xNextTail );
1115         xNextMessageLength = ( size_t ) xTempNextMessageLength;
1116
1117         /* Reduce the number of bytes available by the number of bytes just
1118          * read out. */
1119         xBytesAvailable -= sbBYTES_TO_STORE_MESSAGE_LENGTH;
1120
1121         /* Check there is enough space in the buffer provided by the
1122          * user. */
1123         if( xNextMessageLength > xBufferLengthBytes )
1124         {
1125             /* The user has provided insufficient space to read the message. */
1126             xNextMessageLength = 0;
1127         }
1128         else
1129         {
1130             mtCOVERAGE_TEST_MARKER();
1131         }
1132     }
1133     else
1134     {
1135         /* A stream of bytes is being received (as opposed to a discrete
1136          * message), so read as many bytes as possible. */
1137         xNextMessageLength = xBufferLengthBytes;
1138     }
1139
1140     /* Use the minimum of the wanted bytes and the available bytes. */
1141     xCount = configMIN( xNextMessageLength, xBytesAvailable );
1142
1143     if( xCount != ( size_t ) 0 )
1144     {
1145         /* Read the actual data and update the tail to mark the data as officially consumed. */
1146         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. */
1147     }
1148
1149     return xCount;
1150 }
1151 /*-----------------------------------------------------------*/
1152
1153 BaseType_t xStreamBufferIsEmpty( StreamBufferHandle_t xStreamBuffer )
1154 {
1155     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1156     BaseType_t xReturn;
1157     size_t xTail;
1158
1159     configASSERT( pxStreamBuffer );
1160
1161     /* True if no bytes are available. */
1162     xTail = pxStreamBuffer->xTail;
1163
1164     if( pxStreamBuffer->xHead == xTail )
1165     {
1166         xReturn = pdTRUE;
1167     }
1168     else
1169     {
1170         xReturn = pdFALSE;
1171     }
1172
1173     return xReturn;
1174 }
1175 /*-----------------------------------------------------------*/
1176
1177 BaseType_t xStreamBufferIsFull( StreamBufferHandle_t xStreamBuffer )
1178 {
1179     BaseType_t xReturn;
1180     size_t xBytesToStoreMessageLength;
1181     const StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1182
1183     configASSERT( pxStreamBuffer );
1184
1185     /* This generic version of the receive function is used by both message
1186      * buffers, which store discrete messages, and stream buffers, which store a
1187      * continuous stream of bytes.  Discrete messages include an additional
1188      * sbBYTES_TO_STORE_MESSAGE_LENGTH bytes that hold the length of the message. */
1189     if( ( pxStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER ) != ( uint8_t ) 0 )
1190     {
1191         xBytesToStoreMessageLength = sbBYTES_TO_STORE_MESSAGE_LENGTH;
1192     }
1193     else
1194     {
1195         xBytesToStoreMessageLength = 0;
1196     }
1197
1198     /* True if the available space equals zero. */
1199     if( xStreamBufferSpacesAvailable( xStreamBuffer ) <= xBytesToStoreMessageLength )
1200     {
1201         xReturn = pdTRUE;
1202     }
1203     else
1204     {
1205         xReturn = pdFALSE;
1206     }
1207
1208     return xReturn;
1209 }
1210 /*-----------------------------------------------------------*/
1211
1212 BaseType_t xStreamBufferSendCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1213                                               BaseType_t * pxHigherPriorityTaskWoken )
1214 {
1215     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1216     BaseType_t xReturn;
1217     UBaseType_t uxSavedInterruptStatus;
1218
1219     configASSERT( pxStreamBuffer );
1220
1221     uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();
1222     {
1223         if( ( pxStreamBuffer )->xTaskWaitingToReceive != NULL )
1224         {
1225             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToReceive,
1226                                          ( uint32_t ) 0,
1227                                          eNoAction,
1228                                          pxHigherPriorityTaskWoken );
1229             ( pxStreamBuffer )->xTaskWaitingToReceive = NULL;
1230             xReturn = pdTRUE;
1231         }
1232         else
1233         {
1234             xReturn = pdFALSE;
1235         }
1236     }
1237     portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );
1238
1239     return xReturn;
1240 }
1241 /*-----------------------------------------------------------*/
1242
1243 BaseType_t xStreamBufferReceiveCompletedFromISR( StreamBufferHandle_t xStreamBuffer,
1244                                                  BaseType_t * pxHigherPriorityTaskWoken )
1245 {
1246     StreamBuffer_t * const pxStreamBuffer = xStreamBuffer;
1247     BaseType_t xReturn;
1248     UBaseType_t uxSavedInterruptStatus;
1249
1250     configASSERT( pxStreamBuffer );
1251
1252     uxSavedInterruptStatus = portSET_INTERRUPT_MASK_FROM_ISR();
1253     {
1254         if( ( pxStreamBuffer )->xTaskWaitingToSend != NULL )
1255         {
1256             ( void ) xTaskNotifyFromISR( ( pxStreamBuffer )->xTaskWaitingToSend,
1257                                          ( uint32_t ) 0,
1258                                          eNoAction,
1259                                          pxHigherPriorityTaskWoken );
1260             ( pxStreamBuffer )->xTaskWaitingToSend = NULL;
1261             xReturn = pdTRUE;
1262         }
1263         else
1264         {
1265             xReturn = pdFALSE;
1266         }
1267     }
1268     portCLEAR_INTERRUPT_MASK_FROM_ISR( uxSavedInterruptStatus );
1269
1270     return xReturn;
1271 }
1272 /*-----------------------------------------------------------*/
1273
1274 static size_t prvWriteBytesToBuffer( StreamBuffer_t * const pxStreamBuffer,
1275                                      const uint8_t * pucData,
1276                                      size_t xCount,
1277                                      size_t xHead )
1278 {
1279     size_t xFirstLength;
1280
1281     configASSERT( xCount > ( size_t ) 0 );
1282
1283     /* Calculate the number of bytes that can be added in the first write -
1284      * which may be less than the total number of bytes that need to be added if
1285      * the buffer will wrap back to the beginning. */
1286     xFirstLength = configMIN( pxStreamBuffer->xLength - xHead, xCount );
1287
1288     /* Write as many bytes as can be written in the first write. */
1289     configASSERT( ( xHead + xFirstLength ) <= pxStreamBuffer->xLength );
1290     ( void ) memcpy( ( void * ) ( &( pxStreamBuffer->pucBuffer[ xHead ] ) ), ( const void * ) pucData, xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1291
1292     /* If the number of bytes written was less than the number that could be
1293      * written in the first write... */
1294     if( xCount > xFirstLength )
1295     {
1296         /* ...then write the remaining bytes to the start of the buffer. */
1297         configASSERT( ( xCount - xFirstLength ) <= pxStreamBuffer->xLength );
1298         ( void ) memcpy( ( void * ) pxStreamBuffer->pucBuffer, ( const void * ) &( pucData[ xFirstLength ] ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1299     }
1300     else
1301     {
1302         mtCOVERAGE_TEST_MARKER();
1303     }
1304
1305     xHead += xCount;
1306
1307     if( xHead >= pxStreamBuffer->xLength )
1308     {
1309         xHead -= pxStreamBuffer->xLength;
1310     }
1311     else
1312     {
1313         mtCOVERAGE_TEST_MARKER();
1314     }
1315
1316     return xHead;
1317 }
1318 /*-----------------------------------------------------------*/
1319
1320 static size_t prvReadBytesFromBuffer( StreamBuffer_t * pxStreamBuffer,
1321                                       uint8_t * pucData,
1322                                       size_t xCount,
1323                                       size_t xTail )
1324 {
1325     size_t xFirstLength;
1326
1327     configASSERT( xCount != ( size_t ) 0 );
1328
1329     /* Calculate the number of bytes that can be read - which may be
1330      * less than the number wanted if the data wraps around to the start of
1331      * the buffer. */
1332     xFirstLength = configMIN( pxStreamBuffer->xLength - xTail, xCount );
1333
1334     /* Obtain the number of bytes it is possible to obtain in the first
1335      * read.  Asserts check bounds of read and write. */
1336     configASSERT( xFirstLength <= xCount );
1337     configASSERT( ( xTail + xFirstLength ) <= pxStreamBuffer->xLength );
1338     ( void ) memcpy( ( void * ) pucData, ( const void * ) &( pxStreamBuffer->pucBuffer[ xTail ] ), xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1339
1340     /* If the total number of wanted bytes is greater than the number
1341      * that could be read in the first read... */
1342     if( xCount > xFirstLength )
1343     {
1344         /* ...then read the remaining bytes from the start of the buffer. */
1345         ( void ) memcpy( ( void * ) &( pucData[ xFirstLength ] ), ( void * ) ( pxStreamBuffer->pucBuffer ), xCount - xFirstLength ); /*lint !e9087 memcpy() requires void *. */
1346     }
1347     else
1348     {
1349         mtCOVERAGE_TEST_MARKER();
1350     }
1351
1352     /* Move the tail pointer to effectively remove the data read from the buffer. */
1353     xTail += xCount;
1354
1355     if( xTail >= pxStreamBuffer->xLength )
1356     {
1357         xTail -= pxStreamBuffer->xLength;
1358     }
1359
1360     return xTail;
1361 }
1362 /*-----------------------------------------------------------*/
1363
1364 static size_t prvBytesInBuffer( const StreamBuffer_t * const pxStreamBuffer )
1365 {
1366 /* Returns the distance between xTail and xHead. */
1367     size_t xCount;
1368
1369     xCount = pxStreamBuffer->xLength + pxStreamBuffer->xHead;
1370     xCount -= pxStreamBuffer->xTail;
1371
1372     if( xCount >= pxStreamBuffer->xLength )
1373     {
1374         xCount -= pxStreamBuffer->xLength;
1375     }
1376     else
1377     {
1378         mtCOVERAGE_TEST_MARKER();
1379     }
1380
1381     return xCount;
1382 }
1383 /*-----------------------------------------------------------*/
1384
1385 static void prvInitialiseNewStreamBuffer( StreamBuffer_t * const pxStreamBuffer,
1386                                           uint8_t * const pucBuffer,
1387                                           size_t xBufferSizeBytes,
1388                                           size_t xTriggerLevelBytes,
1389                                           uint8_t ucFlags,
1390                                           StreamBufferCallbackFunction_t pxSendCompletedCallback,
1391                                           StreamBufferCallbackFunction_t pxReceiveCompletedCallback )
1392 {
1393     /* Assert here is deliberately writing to the entire buffer to ensure it can
1394      * be written to without generating exceptions, and is setting the buffer to a
1395      * known value to assist in development/debugging. */
1396     #if ( configASSERT_DEFINED == 1 )
1397     {
1398         /* The value written just has to be identifiable when looking at the
1399          * memory.  Don't use 0xA5 as that is the stack fill value and could
1400          * result in confusion as to what is actually being observed. */
1401     #define STREAM_BUFFER_BUFFER_WRITE_VALUE    ( 0x55 )
1402         configASSERT( memset( pucBuffer, ( int ) STREAM_BUFFER_BUFFER_WRITE_VALUE, xBufferSizeBytes ) == pucBuffer );
1403     }
1404     #endif
1405
1406     ( void ) memset( ( void * ) pxStreamBuffer, 0x00, sizeof( StreamBuffer_t ) ); /*lint !e9087 memset() requires void *. */
1407     pxStreamBuffer->pucBuffer = pucBuffer;
1408     pxStreamBuffer->xLength = xBufferSizeBytes;
1409     pxStreamBuffer->xTriggerLevelBytes = xTriggerLevelBytes;
1410     pxStreamBuffer->ucFlags = ucFlags;
1411     #if ( configUSE_SB_COMPLETED_CALLBACK == 1 )
1412     {
1413         pxStreamBuffer->pxSendCompletedCallback = pxSendCompletedCallback;
1414         pxStreamBuffer->pxReceiveCompletedCallback = pxReceiveCompletedCallback;
1415     }
1416     #else
1417     {
1418         ( void ) pxSendCompletedCallback;
1419         ( void ) pxReceiveCompletedCallback;
1420     }
1421     #endif
1422 }
1423
1424 #if ( configUSE_TRACE_FACILITY == 1 )
1425
1426     UBaseType_t uxStreamBufferGetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer )
1427     {
1428         return xStreamBuffer->uxStreamBufferNumber;
1429     }
1430
1431 #endif /* configUSE_TRACE_FACILITY */
1432 /*-----------------------------------------------------------*/
1433
1434 #if ( configUSE_TRACE_FACILITY == 1 )
1435
1436     void vStreamBufferSetStreamBufferNumber( StreamBufferHandle_t xStreamBuffer,
1437                                              UBaseType_t uxStreamBufferNumber )
1438     {
1439         xStreamBuffer->uxStreamBufferNumber = uxStreamBufferNumber;
1440     }
1441
1442 #endif /* configUSE_TRACE_FACILITY */
1443 /*-----------------------------------------------------------*/
1444
1445 #if ( configUSE_TRACE_FACILITY == 1 )
1446
1447     uint8_t ucStreamBufferGetStreamBufferType( StreamBufferHandle_t xStreamBuffer )
1448     {
1449         return( xStreamBuffer->ucFlags & sbFLAGS_IS_MESSAGE_BUFFER );
1450     }
1451
1452 #endif /* configUSE_TRACE_FACILITY */
1453 /*-----------------------------------------------------------*/