root/webserver/example/freeRTOSexample/Source/portable/MemMang/heap_1.c

/*
        FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd.

        This file is part of the FreeRTOS distribution.

        FreeRTOS is free software; you can redistribute it and/or modify it     under 
        the terms of the GNU General Public License (version 2) as published by the 
        Free Software Foundation and modified by the FreeRTOS exception.
        **NOTE** The exception to the GPL is included to allow you to distribute a
        combined work that includes FreeRTOS without being obliged to provide the 
        source code for proprietary components outside of the FreeRTOS kernel.  
        Alternative commercial license and support terms are also available upon 
        request.  See the licensing section of http://www.FreeRTOS.org for full 
        license details.

        FreeRTOS is distributed in the hope that it will be useful,     but WITHOUT
        ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
        FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
        more details.

        You should have received a copy of the GNU General Public License along
        with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
        Temple Place, Suite 330, Boston, MA  02111-1307  USA.


        ***************************************************************************
        *                                                                         *
        * Looking for a quick start?  Then check out the FreeRTOS eBook!          *
        * See http://www.FreeRTOS.org/Documentation for details                   *
        *                                                                         *
        ***************************************************************************

        1 tab == 4 spaces!

        Please ensure to read the configuration and relevant port sections of the
        online documentation.

        http://www.FreeRTOS.org - Documentation, latest information, license and
        contact details.

        http://www.SafeRTOS.com - A version that is certified for use in safety
        critical systems.

        http://www.OpenRTOS.com - Commercial support, development, porting,
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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 and heap_3.c for alternative implementations, and the memory
 * management pages of http://www.FreeRTOS.org for more information.
 */
#include <stdlib.h>
#include "FreeRTOS.h"
#include "task.h"

/* Setup the correct byte alignment mask for the defined byte alignment. */

#if portBYTE_ALIGNMENT == 8
        #define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0007 )
#endif

#if portBYTE_ALIGNMENT == 4
        #define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0003 )
#endif

#if portBYTE_ALIGNMENT == 2
        #define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0001 )
#endif

#if portBYTE_ALIGNMENT == 1 
        #define heapBYTE_ALIGNMENT_MASK ( ( size_t ) 0x0000 )
#endif

#ifndef heapBYTE_ALIGNMENT_MASK
        #error "Invalid portBYTE_ALIGNMENT definition"
#endif

/* Allocate the memory for the heap.  The struct is used to force byte
alignment without using any non-portable code. */
static union xRTOS_HEAP
{
        #if portBYTE_ALIGNMENT == 8
                volatile portDOUBLE dDummy;
        #else
                volatile unsigned portLONG ulDummy;
        #endif  
        unsigned portCHAR ucHeap[ configTOTAL_HEAP_SIZE ];
} xHeap;

static size_t xNextFreeByte = ( size_t ) 0;
/*-----------------------------------------------------------*/

void *pvPortMalloc( size_t xWantedSize )
{
void *pvReturn = NULL; 

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

        vTaskSuspendAll();
        {
                /* Check there is enough room left for the allocation. */
                if( ( ( xNextFreeByte + xWantedSize ) < configTOTAL_HEAP_SIZE ) &&
                        ( ( xNextFreeByte + xWantedSize ) > xNextFreeByte )     )/* Check for overflow. */
                {
                        /* Return the next free byte then increment the index past this
                        block. */
                        pvReturn = &( xHeap.ucHeap[ 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 and heap_3.c 
        for alternative implementations, and the memory management pages of 
        http://www.FreeRTOS.org for more information. */
        ( void ) pv;
}
/*-----------------------------------------------------------*/

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