FreeRTOS/Source/portable/MemMang/heap_1.c

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*/


/*
 * The simplest possible implementation of pvPortMalloc().  Note that this
 * implementation does NOT allow allocated memory to be freed again.
 *
 * See heap_2.c, heap_3.c and heap_4.c for alternative implementations, and the
 * memory management pages of http://www.FreeRTOS.org for more information.
 */
#include <stdlib.h>

/* Defining MPU_WRAPPERS_INCLUDED_FROM_API_FILE prevents task.h from redefining
all the API functions to use the MPU wrappers.  That should only be done when
task.h is included from an application file. */
#define MPU_WRAPPERS_INCLUDED_FROM_API_FILE

#include "FreeRTOS.h"
#include "task.h"

#undef MPU_WRAPPERS_INCLUDED_FROM_API_FILE

/* A few bytes might be lost to byte aligning the heap start address. */
#define configADJUSTED_HEAP_SIZE	( configTOTAL_HEAP_SIZE - portBYTE_ALIGNMENT )

/* Allocate the memory for the heap. */
static unsigned char ucHeap[ configTOTAL_HEAP_SIZE ];
static size_t xNextFreeByte = ( size_t ) 0;

/*-----------------------------------------------------------*/

void *pvPortMalloc( size_t xWantedSize )
{
void *pvReturn = NULL;
static unsigned char *pucAlignedHeap = NULL;

	/* Ensure that blocks are always aligned to the required number of bytes. */
	#if portBYTE_ALIGNMENT != 1
		if( xWantedSize & portBYTE_ALIGNMENT_MASK )
		{
			/* Byte alignment required. */
			xWantedSize += ( portBYTE_ALIGNMENT - ( xWantedSize & portBYTE_ALIGNMENT_MASK ) );
		}
	#endif

	vTaskSuspendAll();
	{
		if( pucAlignedHeap == NULL )
		{
			/* Ensure the heap starts on a correctly aligned boundary. */
			pucAlignedHeap = ( unsigned char * ) ( ( ( portPOINTER_SIZE_TYPE ) &ucHeap[ portBYTE_ALIGNMENT ] ) & ( ( portPOINTER_SIZE_TYPE ) ~portBYTE_ALIGNMENT_MASK ) );
		}

		/* Check there is enough room left for the allocation. */
		if( ( ( xNextFreeByte + xWantedSize ) < configADJUSTED_HEAP_SIZE ) &&
			( ( xNextFreeByte + xWantedSize ) > xNextFreeByte )	)/* Check for overflow. */
		{
			/* Return the next free byte then increment the index past this
			block. */
			pvReturn = pucAlignedHeap + xNextFreeByte;
			xNextFreeByte += xWantedSize;
		}
	}
	xTaskResumeAll();

	#if( configUSE_MALLOC_FAILED_HOOK == 1 )
	{
		if( pvReturn == NULL )
		{
			extern void vApplicationMallocFailedHook( void );
			vApplicationMallocFailedHook();
		}
	}
	#endif

	return pvReturn;
}
/*-----------------------------------------------------------*/

void vPortFree( void *pv )
{
	/* Memory cannot be freed using this scheme.  See heap_2.c, heap_3.c and
	heap_4.c for alternative implementations, and the memory management pages of
	http://www.FreeRTOS.org for more information. */
	( void ) pv;

	/* Force an assert as it is invalid to call this function. */
	configASSERT( pv == NULL );
}
/*-----------------------------------------------------------*/

void vPortInitialiseBlocks( void )
{
	/* Only required when static memory is not cleared. */
	xNextFreeByte = ( size_t ) 0;
}
/*-----------------------------------------------------------*/

size_t xPortGetFreeHeapSize( void )
{
	return ( configADJUSTED_HEAP_SIZE - xNextFreeByte );
}