/**
* \file
* <!--
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* it under the terms of the GNU General Public License as published by
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* 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.
*
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
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* templates or use macros or inline functions from this file, or you compile
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* file does not by itself cause the resulting executable to be covered by
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*
* Copyright 2004 Develer S.r.l. (http://www.develer.com/)
* Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
* -->
*
* \brief Heap subsystem (public interface).
*
* \author Bernie Innocenti <bernie@codewiz.org>
*/
#include "heap.h"
#include <cfg/debug.h> // ASSERT()
#include <string.h> // memset()
#define FREE_FILL_CODE 0xDEAD
#define ALLOC_FILL_CODE 0xBEEF
/*
* This function prototype is deprecated, will change in:
* void heap_init(struct Heap* h, heap_buf_t* memory, size_t size)
* in the next BeRTOS release.
*/
void heap_init(struct Heap* h, void* memory, size_t size)
{
#ifdef _DEBUG
memset(memory, FREE_FILL_CODE, size);
#endif
ASSERT2(((size_t)memory % alignof(heap_buf_t)) == 0,
"memory buffer is unaligned, please use the HEAP_DEFINE_BUF() macro to declare heap buffers!\n");
/* Initialize heap with a single big chunk */
h->FreeList = (MemChunk *)memory;
h->FreeList->next = NULL;
h->FreeList->size = size;
}
void *heap_allocmem(struct Heap* h, size_t size)
{
MemChunk *chunk, *prev;
/* Round size up to the allocation granularity */
size = ROUND_UP2(size, sizeof(MemChunk));
/* Handle allocations of 0 bytes */
if (!size)
size = sizeof(MemChunk);
/* Walk on the free list looking for any chunk big enough to
* fit the requested block size.
*/
for (prev = (MemChunk *)&h->FreeList, chunk = h->FreeList;
chunk;
prev = chunk, chunk = chunk->next)
{
if (chunk->size >= size)
{
if (chunk->size == size)
{
/* Just remove this chunk from the free list */
prev->next = chunk->next;
#ifdef _DEBUG
memset(chunk, ALLOC_FILL_CODE, size);
#endif
return (void *)chunk;
}
else
{
/* Allocate from the END of an existing chunk */
chunk->size -= size;
#ifdef _DEBUG
memset((uint8_t *)chunk + chunk->size, ALLOC_FILL_CODE, size);
#endif
return (void *)((uint8_t *)chunk + chunk->size);
}
}
}
return NULL; /* fail */
}
void heap_freemem(struct Heap* h, void *mem, size_t size)
{
MemChunk *prev;
ASSERT(mem);
#ifdef _DEBUG
memset(mem, FREE_FILL_CODE, size);
#endif
/* Round size up to the allocation granularity */
size = ROUND_UP2(size, sizeof(MemChunk));
/* Handle allocations of 0 bytes */
if (!size)
size = sizeof(MemChunk);
/* Special cases: first chunk in the free list or memory completely full */
ASSERT((uint8_t*)mem != (uint8_t*)h->FreeList);
if (((uint8_t *)mem) < ((uint8_t *)h->FreeList) || !h->FreeList)
{
/* Insert memory block before the current free list head */
prev = (MemChunk *)mem;
prev->next = h->FreeList;
prev->size = size;
h->FreeList = prev;
}
else /* Normal case: not the first chunk in the free list */
{
/*
* Walk on the free list. Stop at the insertion point (when mem
* is between prev and prev->next)
*/
prev = h->FreeList;
while (prev->next < (MemChunk *)mem && prev->next)
prev = prev->next;
/* Make sure mem is not *within* prev */
ASSERT((uint8_t*)mem >= (uint8_t*)prev + prev->size);
/* Should it be merged with previous block? */
if (((uint8_t *)prev) + prev->size == ((uint8_t *)mem))
{
/* Yes */
prev->size += size;
}
else /* not merged with previous chunk */
{
MemChunk *curr = (MemChunk*)mem;
/* insert it after the previous node
* and move the 'prev' pointer forward
* for the following operations
*/
curr->next = prev->next;
curr->size = size;
prev->next = curr;
/* Adjust for the following test */
prev = curr;
}
}
/* Also merge with next chunk? */
if (((uint8_t *)prev) + prev->size == ((uint8_t *)prev->next))
{
prev->size += prev->next->size;
prev->next = prev->next->next;
/* There should be only one merge opportunity, becuase we always merge on free */
ASSERT((uint8_t*)prev + prev->size != (uint8_t*)prev->next);
}
}
/**
* Returns the number of free bytes in a heap.
* \param h the heap to check.
*
* \note The returned value is the sum of all free memory regions
* in the heap.
* Those regions are likely to be *not* contiguous,
* so a successive allocation may fail even if the
* requested amount of memory is lower than the current free space.
*/
size_t heap_freeSpace(struct Heap *h)
{
size_t free_mem = 0;
for (MemChunk *chunk = h->FreeList; chunk; chunk = chunk->next)
free_mem += chunk->size;
return free_mem;
}
#if CONFIG_HEAP_MALLOC
/**
* Standard malloc interface
*/
void *heap_malloc(struct Heap* h, size_t size)
{
size_t *mem;
size += sizeof(size_t);
if ((mem = (size_t*)heap_allocmem(h, size)))
*mem++ = size;
return mem;
}
/**
* Standard calloc interface
*/
void *heap_calloc(struct Heap* h, size_t size)
{
void *mem;
if ((mem = heap_malloc(h, size)))
memset(mem, 0, size);
return mem;
}
/**
* Free a block of memory, determining its size automatically.
*
* \param h Heap from which the block was allocated.
* \param mem Pointer to a block of memory previously allocated with
* either heap_malloc() or heap_calloc().
*
* \note If \a mem is a NULL pointer, no operation is performed.
*
* \note Freeing the same memory block twice has undefined behavior.
*
* \note This function works like the ANSI C free().
*/
void heap_free(struct Heap *h, void *mem)
{
size_t *_mem = (size_t *)mem;
if (_mem)
{
--_mem;
heap_freemem(h, _mem, *_mem);
}
}
#endif /* CONFIG_HEAP_MALLOC */