437 lines
14 KiB
C
437 lines
14 KiB
C
/*
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* FreeRTOS Kernel V10.0.1
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* Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*
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* A sample implementation of pvPortMalloc() and vPortFree() that combines
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* (coalescences) adjacent memory blocks as they are freed, and in so doing
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* limits memory fragmentation.
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*
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* See heap_1.c, heap_2.c and heap_3.c for alternative implementations, and the
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* memory management pages of http://www.FreeRTOS.org for more information.
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*/
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#include <stdlib.h>
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/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
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all the API functions to use the MPU wrappers. That should only be done when
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task.h is included from an application file. */
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#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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#include "FreeRTOS.h"
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#include "task.h"
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#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE
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#if( configSUPPORT_DYNAMIC_ALLOCATION == 0 )
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#error This file must not be used if configSUPPORT_DYNAMIC_ALLOCATION is 0
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#endif
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/* Block sizes must not get too small. */
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#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
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/* Assumes 8bit bytes! */
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#define heapBITS_PER_BYTE ( ( size_t ) 8 )
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/* Allocate the memory for the heap. */
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#if( configAPPLICATION_ALLOCATED_HEAP == 1 )
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/* The application writer has already defined the array used for the RTOS
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heap - probably so it can be placed in a special segment or address. */
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extern uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
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#else
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static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];
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#endif /* configAPPLICATION_ALLOCATED_HEAP */
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/* Define the linked list structure. This is used to link free blocks in order
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of their memory address. */
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typedef struct A_BLOCK_LINK
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{
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struct A_BLOCK_LINK *pxNextFreeBlock; /*<< The next free block in the list. */
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size_t xBlockSize; /*<< The size of the free block. */
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} BlockLink_t;
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/*-----------------------------------------------------------*/
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/*
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* Inserts a block of memory that is being freed into the correct position in
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* the list of free memory blocks. The block being freed will be merged with
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* the block in front it and/or the block behind it if the memory blocks are
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* adjacent to each other.
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*/
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static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert );
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/*
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* Called automatically to setup the required heap structures the first time
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* pvPortMalloc() is called.
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*/
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static void prvHeapInit( void );
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/*-----------------------------------------------------------*/
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/* The size of the structure placed at the beginning of each allocated memory
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block must by correctly byte aligned. */
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static const size_t xHeapStructSize = ( sizeof( BlockLink_t ) + ( ( size_t ) ( portBYTE_ALIGNMENT - 1 ) ) ) & ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
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/* Create a couple of list links to mark the start and end of the list. */
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static BlockLink_t xStart, *pxEnd = NULL;
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/* Keeps track of the number of free bytes remaining, but says nothing about
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fragmentation. */
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static size_t xFreeBytesRemaining = 0U;
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static size_t xMinimumEverFreeBytesRemaining = 0U;
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/* Gets set to the top bit of an size_t type. When this bit in the xBlockSize
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member of an BlockLink_t structure is set then the block belongs to the
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application. When the bit is free the block is still part of the free heap
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space. */
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static size_t xBlockAllocatedBit = 0;
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/*-----------------------------------------------------------*/
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void *pvPortMalloc( size_t xWantedSize )
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{
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BlockLink_t *pxBlock, *pxPreviousBlock, *pxNewBlockLink;
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void *pvReturn = NULL;
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vTaskSuspendAll();
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{
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/* If this is the first call to malloc then the heap will require
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initialisation to setup the list of free blocks. */
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if( pxEnd == NULL )
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{
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prvHeapInit();
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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/* Check the requested block size is not so large that the top bit is
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set. The top bit of the block size member of the BlockLink_t structure
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is used to determine who owns the block - the application or the
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kernel, so it must be free. */
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if( ( xWantedSize & xBlockAllocatedBit ) == 0 )
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{
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/* The wanted size is increased so it can contain a BlockLink_t
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structure in addition to the requested amount of bytes. */
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if( xWantedSize > 0 )
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{
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xWantedSize += xHeapStructSize;
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/* Ensure that blocks are always aligned to the required number
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of bytes. */
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if( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) != 0x00 )
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{
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/* Byte alignment required. */
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xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
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configASSERT( ( xWantedSize & portBYTE_ALIGNMENT_MASK ) == 0 );
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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if( ( xWantedSize > 0 ) && ( xWantedSize <= xFreeBytesRemaining ) )
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{
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/* Traverse the list from the start (lowest address) block until
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one of adequate size is found. */
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pxPreviousBlock = &xStart;
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pxBlock = xStart.pxNextFreeBlock;
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while( ( pxBlock->xBlockSize < xWantedSize ) && ( pxBlock->pxNextFreeBlock != NULL ) )
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{
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pxPreviousBlock = pxBlock;
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pxBlock = pxBlock->pxNextFreeBlock;
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}
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/* If the end marker was reached then a block of adequate size
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was not found. */
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if( pxBlock != pxEnd )
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{
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/* Return the memory space pointed to - jumping over the
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BlockLink_t structure at its start. */
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pvReturn = ( void * ) ( ( ( uint8_t * ) pxPreviousBlock->pxNextFreeBlock ) + xHeapStructSize );
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/* This block is being returned for use so must be taken out
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of the list of free blocks. */
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pxPreviousBlock->pxNextFreeBlock = pxBlock->pxNextFreeBlock;
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/* If the block is larger than required it can be split into
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two. */
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if( ( pxBlock->xBlockSize - xWantedSize ) > heapMINIMUM_BLOCK_SIZE )
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{
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/* This block is to be split into two. Create a new
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block following the number of bytes requested. The void
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cast is used to prevent byte alignment warnings from the
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compiler. */
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pxNewBlockLink = ( void * ) ( ( ( uint8_t * ) pxBlock ) + xWantedSize );
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configASSERT( ( ( ( size_t ) pxNewBlockLink ) & portBYTE_ALIGNMENT_MASK ) == 0 );
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/* Calculate the sizes of two blocks split from the
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single block. */
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pxNewBlockLink->xBlockSize = pxBlock->xBlockSize - xWantedSize;
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pxBlock->xBlockSize = xWantedSize;
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/* Insert the new block into the list of free blocks. */
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prvInsertBlockIntoFreeList( pxNewBlockLink );
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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xFreeBytesRemaining -= pxBlock->xBlockSize;
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if( xFreeBytesRemaining < xMinimumEverFreeBytesRemaining )
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{
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xMinimumEverFreeBytesRemaining = xFreeBytesRemaining;
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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/* The block is being returned - it is allocated and owned
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by the application and has no "next" block. */
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pxBlock->xBlockSize |= xBlockAllocatedBit;
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pxBlock->pxNextFreeBlock = NULL;
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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traceMALLOC( pvReturn, xWantedSize );
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}
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( void ) xTaskResumeAll();
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#if( configUSE_MALLOC_FAILED_HOOK == 1 )
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{
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if( pvReturn == NULL )
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{
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extern void vApplicationMallocFailedHook( void );
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vApplicationMallocFailedHook();
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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#endif
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configASSERT( ( ( ( size_t ) pvReturn ) & ( size_t ) portBYTE_ALIGNMENT_MASK ) == 0 );
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return pvReturn;
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}
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/*-----------------------------------------------------------*/
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void vPortFree( void *pv )
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{
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uint8_t *puc = ( uint8_t * ) pv;
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BlockLink_t *pxLink;
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if( pv != NULL )
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{
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/* The memory being freed will have an BlockLink_t structure immediately
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before it. */
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puc -= xHeapStructSize;
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/* This casting is to keep the compiler from issuing warnings. */
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pxLink = ( void * ) puc;
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/* Check the block is actually allocated. */
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configASSERT( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 );
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configASSERT( pxLink->pxNextFreeBlock == NULL );
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if( ( pxLink->xBlockSize & xBlockAllocatedBit ) != 0 )
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{
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if( pxLink->pxNextFreeBlock == NULL )
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{
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/* The block is being returned to the heap - it is no longer
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allocated. */
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pxLink->xBlockSize &= ~xBlockAllocatedBit;
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vTaskSuspendAll();
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{
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/* Add this block to the list of free blocks. */
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xFreeBytesRemaining += pxLink->xBlockSize;
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traceFREE( pv, pxLink->xBlockSize );
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prvInsertBlockIntoFreeList( ( ( BlockLink_t * ) pxLink ) );
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}
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( void ) xTaskResumeAll();
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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}
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/*-----------------------------------------------------------*/
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size_t xPortGetFreeHeapSize( void )
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{
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return xFreeBytesRemaining;
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}
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/*-----------------------------------------------------------*/
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size_t xPortGetMinimumEverFreeHeapSize( void )
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{
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return xMinimumEverFreeBytesRemaining;
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}
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/*-----------------------------------------------------------*/
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void vPortInitialiseBlocks( void )
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{
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/* This just exists to keep the linker quiet. */
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}
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/*-----------------------------------------------------------*/
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static void prvHeapInit( void )
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{
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BlockLink_t *pxFirstFreeBlock;
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uint8_t *pucAlignedHeap;
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size_t uxAddress;
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size_t xTotalHeapSize = configTOTAL_HEAP_SIZE;
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/* Ensure the heap starts on a correctly aligned boundary. */
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uxAddress = ( size_t ) ucHeap;
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if( ( uxAddress & portBYTE_ALIGNMENT_MASK ) != 0 )
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{
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uxAddress += ( portBYTE_ALIGNMENT - 1 );
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uxAddress &= ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
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xTotalHeapSize -= uxAddress - ( size_t ) ucHeap;
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}
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pucAlignedHeap = ( uint8_t * ) uxAddress;
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/* xStart is used to hold a pointer to the first item in the list of free
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blocks. The void cast is used to prevent compiler warnings. */
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xStart.pxNextFreeBlock = ( void * ) pucAlignedHeap;
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xStart.xBlockSize = ( size_t ) 0;
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/* pxEnd is used to mark the end of the list of free blocks and is inserted
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at the end of the heap space. */
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uxAddress = ( ( size_t ) pucAlignedHeap ) + xTotalHeapSize;
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uxAddress -= xHeapStructSize;
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uxAddress &= ~( ( size_t ) portBYTE_ALIGNMENT_MASK );
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pxEnd = ( void * ) uxAddress;
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pxEnd->xBlockSize = 0;
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pxEnd->pxNextFreeBlock = NULL;
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/* To start with there is a single free block that is sized to take up the
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entire heap space, minus the space taken by pxEnd. */
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pxFirstFreeBlock = ( void * ) pucAlignedHeap;
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pxFirstFreeBlock->xBlockSize = uxAddress - ( size_t ) pxFirstFreeBlock;
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pxFirstFreeBlock->pxNextFreeBlock = pxEnd;
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/* Only one block exists - and it covers the entire usable heap space. */
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xMinimumEverFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
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xFreeBytesRemaining = pxFirstFreeBlock->xBlockSize;
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/* Work out the position of the top bit in a size_t variable. */
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xBlockAllocatedBit = ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 );
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}
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/*-----------------------------------------------------------*/
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static void prvInsertBlockIntoFreeList( BlockLink_t *pxBlockToInsert )
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{
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BlockLink_t *pxIterator;
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uint8_t *puc;
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/* Iterate through the list until a block is found that has a higher address
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than the block being inserted. */
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for( pxIterator = &xStart; pxIterator->pxNextFreeBlock < pxBlockToInsert; pxIterator = pxIterator->pxNextFreeBlock )
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{
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/* Nothing to do here, just iterate to the right position. */
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}
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/* Do the block being inserted, and the block it is being inserted after
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make a contiguous block of memory? */
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puc = ( uint8_t * ) pxIterator;
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if( ( puc + pxIterator->xBlockSize ) == ( uint8_t * ) pxBlockToInsert )
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{
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pxIterator->xBlockSize += pxBlockToInsert->xBlockSize;
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pxBlockToInsert = pxIterator;
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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/* Do the block being inserted, and the block it is being inserted before
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make a contiguous block of memory? */
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puc = ( uint8_t * ) pxBlockToInsert;
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if( ( puc + pxBlockToInsert->xBlockSize ) == ( uint8_t * ) pxIterator->pxNextFreeBlock )
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{
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if( pxIterator->pxNextFreeBlock != pxEnd )
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{
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/* Form one big block from the two blocks. */
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pxBlockToInsert->xBlockSize += pxIterator->pxNextFreeBlock->xBlockSize;
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pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock->pxNextFreeBlock;
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}
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else
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{
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pxBlockToInsert->pxNextFreeBlock = pxEnd;
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}
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}
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else
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{
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pxBlockToInsert->pxNextFreeBlock = pxIterator->pxNextFreeBlock;
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}
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/* If the block being inserted plugged a gab, so was merged with the block
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before and the block after, then it's pxNextFreeBlock pointer will have
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already been set, and should not be set here as that would make it point
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to itself. */
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if( pxIterator != pxBlockToInsert )
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{
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pxIterator->pxNextFreeBlock = pxBlockToInsert;
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}
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else
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{
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mtCOVERAGE_TEST_MARKER();
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}
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}
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