716 lines
17 KiB
C
716 lines
17 KiB
C
#include "mm.h"
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/*块不太小 */
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#define heapMINIMUM_BLOCK_SIZE ( ( size_t ) ( xHeapStructSize << 1 ) )
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/* Assumes 8bit bytes!假设为8位 */
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#define heapBITS_PER_BYTE ( ( size_t ) 8 )
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/* Max value that fits in a size_t type. size_t最大值 */
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#define heapSIZE_MAX ( ~( ( size_t ) 0 ) )
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/* Check if multiplying a and b will result in overflow. 检查a 和B 相乘是否会溢出*/
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#define heapMULTIPLY_WILL_OVERFLOW( a, b ) ( ( ( a ) > 0 ) && ( ( b ) > ( heapSIZE_MAX / ( a ) ) ) )
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/* Check if adding a and b will result in overflow. 检查a 和b相加是否会溢出*/
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#define heapADD_WILL_OVERFLOW( a, b ) ( ( a ) > ( heapSIZE_MAX - ( b ) ) )
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/* BlockLink_t结构中的xBlockSize成员的最高有效位（MSB）用于追踪块的分配状态。
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当设置了BlockLink_t结构中的xBlockSize成员的MSB时，该块被归属于应用程序。
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而当该位为空闲时，该块仍然是空闲堆空间的一部分。 */
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#define heapBLOCK_ALLOCATED_BITMASK ( ( ( size_t ) 1 ) << ( ( sizeof( size_t ) * heapBITS_PER_BYTE ) - 1 ) ) //内存对齐使用
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#define heapBLOCK_SIZE_IS_VALID( xBlockSize ) ( ( ( xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) == 0 )
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#define heapBLOCK_IS_ALLOCATED( pxBlock ) ( ( ( pxBlock->xBlockSize ) & heapBLOCK_ALLOCATED_BITMASK ) != 0 )
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#define heapALLOCATE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) |= heapBLOCK_ALLOCATED_BITMASK )
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#define heapFREE_BLOCK( pxBlock ) ( ( pxBlock->xBlockSize ) &= ~heapBLOCK_ALLOCATED_BITMASK )
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static uint8_t ucHeap[ configTOTAL_HEAP_SIZE ];//堆内存大小分配
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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. 下一个空闲块*/
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size_t xBlockSize; /*<< The size of the free block.空闲块的大小 */
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} BlockLink_t;
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/* 将正在释放的内存块插入到空闲内存块列表中的正确位置。
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如果内存块彼此相邻，被释放的块将与它前面的块和/或它后面的块合并。 */
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static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert );
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static void prvHeapInit( void );
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/* 位于每个分配的内存块开头的结构的大小必须按正确的字节对齐。 */
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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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/* 创建两个列表链接来标记列表的开始和结束。*/
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static BlockLink_t xStart;
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static BlockLink_t * pxEnd = NULL;//如果不是NULL就是已经初始化话内存了,这个很重要
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/* 跟踪分配和释放内存的调用数量以及剩余空闲字节数，但没有说明碎片。* / */
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static size_t xFreeBytesRemaining = 0U;
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static size_t xMinimumEverFreeBytesRemaining = 0U;
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static size_t xNumberOfSuccessfulAllocations = 0;
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static size_t xNumberOfSuccessfulFrees = 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;
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BlockLink_t * pxPreviousBlock;
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BlockLink_t * pxNewBlockLink;
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void * pvReturn = NULL;
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size_t xAdditionalRequiredSize;
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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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if( xWantedSize > 0 )
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{
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/* The wanted size must be increased so it can contain a BlockLink_t
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* structure in addition to the requested amount of bytes. Some
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* additional increment may also be needed for alignment. */
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xAdditionalRequiredSize = xHeapStructSize + portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK );
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if( heapADD_WILL_OVERFLOW( xWantedSize, xAdditionalRequiredSize ) == 0 )
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{
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xWantedSize += xAdditionalRequiredSize;
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}
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else
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{
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xWantedSize = 0;
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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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/* Check the block size we are trying to allocate is not so large that the
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* top bit is set. The top bit of the block size member of the BlockLink_t
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* structure is used to determine who owns the block - the application or
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* the kernel, so it must be free. */
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if( heapBLOCK_SIZE_IS_VALID( xWantedSize ) != 0 )
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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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heapALLOCATE_BLOCK( pxBlock );
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pxBlock->pxNextFreeBlock = NULL;
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xNumberOfSuccessfulAllocations++;
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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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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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configASSERT( heapBLOCK_IS_ALLOCATED( pxLink ) != 0 );
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configASSERT( pxLink->pxNextFreeBlock == NULL );
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if( heapBLOCK_IS_ALLOCATED( pxLink ) != 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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heapFREE_BLOCK( pxLink );
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#if ( configHEAP_CLEAR_MEMORY_ON_FREE == 1 )
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{
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( void ) memset( puc + xHeapStructSize, 0, pxLink->xBlockSize - xHeapStructSize );
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}
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#endif
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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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xNumberOfSuccessfulFrees++;
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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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}
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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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void * pvPortCalloc( size_t xNum,
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size_t xSize )
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{
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void * pv = NULL;
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if( heapMULTIPLY_WILL_OVERFLOW( xNum, xSize ) == 0 )
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{
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pv = pvPortMalloc( xNum * xSize );
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if( pv != NULL )
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{
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( void ) memset( pv, 0, xNum * xSize );
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}
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}
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return pv;
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}
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/*-----------------------------------------------------------*/
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static void prvHeapInit( void ) /* PRIVILEGED_FUNCTION */
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{
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BlockLink_t * pxFirstFreeBlock;
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uint8_t * pucAlignedHeap;
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portPOINTER_SIZE_TYPE 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 = ( portPOINTER_SIZE_TYPE ) 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 &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
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xTotalHeapSize -= uxAddress - ( portPOINTER_SIZE_TYPE ) 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 = ( ( portPOINTER_SIZE_TYPE ) pucAlignedHeap ) + xTotalHeapSize;
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uxAddress -= xHeapStructSize;
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uxAddress &= ~( ( portPOINTER_SIZE_TYPE ) portBYTE_ALIGNMENT_MASK );
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pxEnd = ( BlockLink_t * ) 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 = ( BlockLink_t * ) pucAlignedHeap;
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pxFirstFreeBlock->xBlockSize = ( size_t ) ( uxAddress - ( portPOINTER_SIZE_TYPE ) 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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}
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/*-----------------------------------------------------------*/
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static void prvInsertBlockIntoFreeList( BlockLink_t * pxBlockToInsert ) /* PRIVILEGED_FUNCTION */
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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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/*-----------------------------------------------------------*/
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void vPortGetHeapStats( HeapStats_t * pxHeapStats )
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{
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BlockLink_t * pxBlock;
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size_t xBlocks = 0, xMaxSize = 0, xMinSize = portMAX_DELAY; /* portMAX_DELAY used as a portable way of getting the maximum value. */
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{
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pxBlock = xStart.pxNextFreeBlock;
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/* pxBlock will be NULL if the heap has not been initialised. The heap
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* is initialised automatically when the first allocation is made. */
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if( pxBlock != NULL )
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{
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while( pxBlock != pxEnd )
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{
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/* Increment the number of blocks and record the largest block seen
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* so far. */
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xBlocks++;
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if( pxBlock->xBlockSize > xMaxSize )
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{
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xMaxSize = pxBlock->xBlockSize;
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}
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if( pxBlock->xBlockSize < xMinSize )
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{
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xMinSize = pxBlock->xBlockSize;
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}
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/* Move to the next block in the chain until the last block is
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* reached. */
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pxBlock = pxBlock->pxNextFreeBlock;
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}
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}
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}
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pxHeapStats->xSizeOfLargestFreeBlockInBytes = xMaxSize;
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pxHeapStats->xSizeOfSmallestFreeBlockInBytes = xMinSize;
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pxHeapStats->xNumberOfFreeBlocks = xBlocks;
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{
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pxHeapStats->xAvailableHeapSpaceInBytes = xFreeBytesRemaining;
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pxHeapStats->xNumberOfSuccessfulAllocations = xNumberOfSuccessfulAllocations;
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pxHeapStats->xNumberOfSuccessfulFrees = xNumberOfSuccessfulFrees;
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pxHeapStats->xMinimumEverFreeBytesRemaining = xMinimumEverFreeBytesRemaining;
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}
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}
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/*-----------------------------------------------------------*/
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/*-----------------------------------------------------------*/
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void* myRealloc(void* ptr, size_t newSize) {
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void* newPtr = pvPortMalloc(newSize);
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if (newPtr != NULL) {
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// 复制旧内存的数据到新内存
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size_t copySize = newSize; // 这里可以根据需要进行调整
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memcpy(newPtr, ptr, copySize);
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// 释放旧的内存
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vPortFree(ptr);
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}
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return newPtr;
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}
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/*-----------------------------------------------------------*/
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