/*
* Initializes the heap state variables
*/
PmReturn_t
heap_init(void)
{
pPmHeapDesc_t pchunk;
#if PM_HEAP_SIZE > 65535
uint32_t hs;
#else
uint16_t hs;
#endif
#if __DEBUG__
/* Fill the heap with a non-NULL value to bring out any heap bugs. */
sli_memset(pmHeap.base, 0xAA, sizeof(pmHeap.base));
#endif
/* Init heap globals */
pmHeap.pfreelist = C_NULL;
pmHeap.avail = 0;
#ifdef HAVE_GC
pmHeap.gcval = (uint8_t)0;
pmHeap.temp_root_index = (uint8_t)0;
heap_gcSetAuto(C_TRUE);
#endif /* HAVE_GC */
/* Create as many max-sized chunks as possible in the freelist */
for (pchunk = (pPmHeapDesc_t)pmHeap.base, hs = PM_HEAP_SIZE;
hs >= HEAP_MAX_FREE_CHUNK_SIZE; hs -= HEAP_MAX_FREE_CHUNK_SIZE)
{
OBJ_SET_FREE(pchunk, 1);
OBJ_SET_SIZE(pchunk, HEAP_MAX_FREE_CHUNK_SIZE);
heap_linkToFreelist(pchunk);
pchunk =
(pPmHeapDesc_t)((uint8_t *)pchunk + HEAP_MAX_FREE_CHUNK_SIZE);
}
/* Add any leftover memory to the freelist */
if (hs >= HEAP_MIN_CHUNK_SIZE)
{
/* Round down to a multiple of four */
hs = hs & ~3;
OBJ_SET_FREE(pchunk, 1);
OBJ_SET_SIZE(pchunk, hs);
heap_linkToFreelist(pchunk);
}
C_DEBUG_PRINT(VERBOSITY_LOW, "heap_init(), id=%p, s=%d\n",
pmHeap.base, pmHeap.avail);
string_cacheInit();
return PM_RET_OK;
}
/*
* Initializes the heap state variables
*/
PmReturn_t
heap_init(void)
{
pPmHeapDesc_t pchunk;
/* Create one big chunk */
pchunk = (pPmHeapDesc_t)pmHeap.base;
OBJ_SET_FREE(pchunk, 1);
OBJ_SET_SIZE(pchunk, HEAP_SIZE);
pchunk->next = C_NULL;
pchunk->prev = C_NULL;
/* Init heap globals */
pmHeap.pfreelist = pchunk;
pmHeap.avail = HEAP_SIZE;
pmHeap.gcval = (uint8_t)0;
pmHeap.auto_gc = C_TRUE;
C_DEBUG_PRINT(VERBOSITY_LOW, "heap_init(), id=%p, s=%d\n",
pmHeap.base, HEAP_SIZE);
string_cacheInit();
return PM_RET_OK;
}
/* Releases chunk to the free list */
PmReturn_t
heap_freeChunk(pPmObj_t ptr)
{
PmReturn_t retval;
C_DEBUG_PRINT(VERBOSITY_HIGH, "heap_freeChunk(), id=%p, s=%d\n",
ptr, OBJ_GET_SIZE(ptr));
/* Ensure the chunk falls within the heap */
C_ASSERT(((uint8_t *)ptr >= pmHeap.base)
&& ((uint8_t *)ptr < pmHeap.base + PM_HEAP_SIZE));
/* Insert the chunk into the freelist */
OBJ_SET_FREE(ptr, 1);
/* Clear type so that heap descriptor's size's upper byte is zero */
OBJ_SET_TYPE(ptr, 0);
retval = heap_linkToFreelist((pPmHeapDesc_t)ptr);
PM_RETURN_IF_ERROR(retval);
return retval;
}
/**
* Obtains a chunk of memory from the free list
*
* Performs the Best Fit algorithm.
* Iterates through the freelist to see if a chunk of suitable size exists.
* Shaves a chunk to perfect size iff the remainder is greater than
* the minimum chunk size.
*
* @param size Requested chunk size
* @param r_pchunk Return ptr to chunk
* @return Return status
*/
static PmReturn_t
heap_getChunkImpl(uint16_t size, uint8_t **r_pchunk)
{
PmReturn_t retval;
pPmHeapDesc_t pchunk;
pPmHeapDesc_t premainderChunk;
C_ASSERT(r_pchunk != C_NULL);
/* Skip to the first chunk that can hold the requested size */
pchunk = pmHeap.pfreelist;
while ((pchunk != C_NULL) && (OBJ_GET_SIZE(pchunk) < size))
{
pchunk = pchunk->next;
}
/* No chunk of appropriate size was found, raise OutOfMemory exception */
if (pchunk == C_NULL)
{
*r_pchunk = C_NULL;
PM_RAISE(retval, PM_RET_EX_MEM);
return retval;
}
/* Remove the chunk from the free list */
retval = heap_unlinkFromFreelist(pchunk);
PM_RETURN_IF_ERROR(retval);
/* Check if a chunk should be carved from what is available */
if (OBJ_GET_SIZE(pchunk) - size >= HEAP_MIN_CHUNK_SIZE)
{
/* Create the heap descriptor for the remainder chunk */
premainderChunk = (pPmHeapDesc_t)((uint8_t *)pchunk + size);
OBJ_SET_FREE(premainderChunk, 1);
OBJ_SET_SIZE(premainderChunk, OBJ_GET_SIZE(pchunk) - size);
/* Put the remainder chunk back in the free list */
retval = heap_linkToFreelist(premainderChunk);
PM_RETURN_IF_ERROR(retval);
/* Convert the chunk from a heap descriptor to an object descriptor */
OBJ_SET_SIZE(pchunk, 0);
OBJ_SET_FREE(pchunk, 0);
OBJ_SET_SIZE(pchunk, size);
C_DEBUG_PRINT(VERBOSITY_HIGH,
"heap_getChunkImpl()carved, id=%p, s=%d\n", pchunk,
size);
}
else
{
/* Set chunk's type to none (overwrites size field's high byte) */
OBJ_SET_TYPE((pPmObj_t)pchunk, OBJ_TYPE_NON);
OBJ_SET_FREE(pchunk, 0);
C_DEBUG_PRINT(VERBOSITY_HIGH,
"heap_getChunkImpl()exact, id=%p, s=%d\n", pchunk,
OBJ_GET_SIZE(pchunk));
}
/*
* Set the chunk's GC mark so it will be collected during the next GC cycle
* if it is not reachable
*/
OBJ_SET_GCVAL(pchunk, pmHeap.gcval);
/* Return the chunk */
*r_pchunk = (uint8_t *)pchunk;
return retval;
}
/*
* Reclaims any object that does not have a current mark.
* Puts it in the free list. Coalesces all contiguous free chunks.
*/
static PmReturn_t
heap_gcSweep(void)
{
PmReturn_t retval;
pPmObj_t pobj;
pPmHeapDesc_t pchunk;
uint16_t totalchunksize;
#if USE_STRING_CACHE
retval = heap_purgeStringCache(pmHeap.gcval);
#endif
/* Start at the base of the heap */
pobj = (pPmObj_t)pmHeap.base;
while ((uint8_t *)pobj < &pmHeap.base[PM_HEAP_SIZE])
{
/* Skip to the next unmarked or free chunk within the heap */
while (!OBJ_GET_FREE(pobj)
&& (OBJ_GET_GCVAL(pobj) == pmHeap.gcval)
&& ((uint8_t *)pobj < &pmHeap.base[PM_HEAP_SIZE]))
{
pobj = (pPmObj_t)((uint8_t *)pobj + OBJ_GET_SIZE(pobj));
}
/* Stop if reached the end of the heap */
if ((uint8_t *)pobj >= &pmHeap.base[PM_HEAP_SIZE])
{
break;
}
/* Accumulate the sizes of all consecutive unmarked or free chunks */
totalchunksize = 0;
/* Coalesce all contiguous free chunks */
pchunk = (pPmHeapDesc_t)pobj;
while (OBJ_GET_FREE(pchunk)
|| (!OBJ_GET_FREE(pchunk)
&& (OBJ_GET_GCVAL(pchunk) != pmHeap.gcval)))
{
if ((totalchunksize + OBJ_GET_SIZE(pchunk))
> HEAP_MAX_FREE_CHUNK_SIZE)
{
break;
}
totalchunksize = totalchunksize + OBJ_GET_SIZE(pchunk);
/*
* If the chunk is already free, unlink it because its size
* is about to change
*/
if (OBJ_GET_FREE(pchunk))
{
retval = heap_unlinkFromFreelist(pchunk);
PM_RETURN_IF_ERROR(retval);
}
/* Otherwise free and reclaim the unmarked chunk */
else
{
OBJ_SET_TYPE(pchunk, 0);
OBJ_SET_FREE(pchunk, 1);
}
C_DEBUG_PRINT(VERBOSITY_HIGH, "heap_gcSweep(), id=%p, s=%d\n",
pchunk, OBJ_GET_SIZE(pchunk));
/* Proceed to the next chunk */
pchunk = (pPmHeapDesc_t)
((uint8_t *)pchunk + OBJ_GET_SIZE(pchunk));
/* Stop if it's past the end of the heap */
if ((uint8_t *)pchunk >= &pmHeap.base[PM_HEAP_SIZE])
{
break;
}
}
/* Set the heap descriptor data */
OBJ_SET_FREE(pobj, 1);
OBJ_SET_SIZE(pobj, totalchunksize);
/* Insert chunk into free list */
retval = heap_linkToFreelist((pPmHeapDesc_t)pobj);
PM_RETURN_IF_ERROR(retval);
/* Continue to the next chunk */
pobj = (pPmObj_t)pchunk;
}
return PM_RET_OK;
}
/*
* Reclaims any object that doesn't have a current mark.
* Puts it in the free list. Coalesces all contiguous free chunks.
*/
static PmReturn_t
heap_gcSweep(void)
{
PmReturn_t retval;
pPmObj_t pobj;
pPmHeapDesc_t pchunk;
uint16_t totalchunksize;
uint16_t additionalheapsize;
/* Start at the base of the heap */
pobj = (pPmObj_t)pmHeap.base;
while ((uint8_t *)pobj < &pmHeap.base[HEAP_SIZE])
{
/* Skip to the next unmarked or free chunk within the heap */
while (!OBJ_GET_FREE(pobj)
&& (OBJ_GET_GCVAL(pobj) == pmHeap.gcval)
&& ((uint8_t *)pobj < &pmHeap.base[HEAP_SIZE]))
{
pobj = (pPmObj_t)((uint8_t *)pobj + OBJ_GET_SIZE(pobj));
/*printf("Object is at addr <%x>\n",(uint32_t)pobj);*/
#if 0
printf("pobj=");obj_print(pobj,0);printf("; type=%x; size=%x\n",OBJ_GET_TYPE(pobj),OBJ_GET_SIZE(pobj));
#endif
}
/* Stop if reached the end of the heap */
if ((uint8_t *)pobj >= &pmHeap.base[HEAP_SIZE])
{
break;
}
/* Accumulate the sizes of all consecutive unmarked or free chunks */
totalchunksize = 0;
additionalheapsize = 0;
/* Coalesce all contiguous free chunks */
pchunk = (pPmHeapDesc_t)pobj;
while (OBJ_GET_FREE(pchunk)
|| (!OBJ_GET_FREE(pchunk)
&& (OBJ_GET_GCVAL(pchunk) != pmHeap.gcval)))
{
totalchunksize += OBJ_GET_SIZE(pchunk);
/*
* If the chunk is already free, unlink it because its size
* is about to change
*/
if (OBJ_GET_FREE(pchunk))
{
retval = heap_unlinkFromFreelist(pchunk);
PM_RETURN_IF_ERROR(retval);
}
/* Otherwise free and reclaim the unmarked chunk */
else
{
OBJ_SET_TYPE(pchunk, 0);
OBJ_SET_FREE(pchunk, 1);
additionalheapsize += OBJ_GET_SIZE(pchunk);
}
C_DEBUG_PRINT(VERBOSITY_HIGH, "heap_gcSweep(), id=%p, s=%d\n",
pchunk, OBJ_GET_SIZE(pchunk));
#if 0
/* It's possible for 0-sized chunks to exist (which makes no sense) TODO:solve */
/* They result in infinite loops, so we must curtail them */
if (OBJ_GET_SIZE(pchunk) == 0)
{
break;
}
#endif
/* Proceed to the next chunk */
pchunk = (pPmHeapDesc_t)
((uint8_t *)pchunk + OBJ_GET_SIZE(pchunk));
/* Stop if it's past the end of the heap */
if ((uint8_t *)pchunk >= &pmHeap.base[HEAP_SIZE])
{
break;
}
}
/* Adjust the heap stats */
pmHeap.avail += additionalheapsize;
/* Set the heap descriptor data */
OBJ_SET_FREE(pobj, 1);
OBJ_SET_SIZE(pobj, totalchunksize);
#if 0
/* avoid loops by breaking on 0-size */
if (totalchunksize == 0)
{
break;
}
#endif
/* Insert chunk into free list */
retval = heap_linkToFreelist((pPmHeapDesc_t)pobj);
PM_RETURN_IF_ERROR(retval);
/* Continue to the next chunk */
pobj = (pPmObj_t)pchunk;
}
return PM_RET_OK;
}