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source: tos.interfaces.MemAlloc.nc

Interface: MemAlloc

Interface for dynamic memory allocators.

Components providing this interface:: tos.lib.TinyAlloc

Components requiring this interface:: tos.lib.TinyDB.AggOperator
tos.lib.TinyDB.DBBufferC
tos.lib.TinyDB.QueryResult
tos.lib.TinyDB.TupleRouterM

Commands

result_t allocate (HandlePtr handle, int16_t size) Allocate a memory region.
result_t reallocate (Handle handle, int16_t size) Reallocate a region to a new size, copying data over.
result_t lock (Handle handle) Lock a memory region from being compacted.
result_t unlock (Handle handle) Unlock a memory region to allow its compaction.
int16_t free (Handle handle) Deallocate a memory region and return it to allocatable memory.
result_t compact (void) Compact the allocated regions to prevent fragmentation.
int16_t size (Handle handle) Get the size of a memory region.
bool isLocked (Handle handle) Get whether a region is locked from compaction.
uint16_t freeBytes (void) Return the number of free bytes available in the heap.

Events

result_t allocComplete (HandlePtr handle, result_t success) Signals when an allocation request has completed.
result_t reallocComplete (Handle handle, result_t success) Signals when an reallocation request has completed.
result_t compactComplete (void) Signals when a compaction request has completed.

Commands - Details

allocate

result_t allocate(HandlePtr handle, int16_t size)

Allocate a memory region.

Parameters:	handle - Handle to memory region (to be filled in). size - Size of region in bytes.
Returns:	SUCCESS if allocated, FAIL otherwise.

reallocate

result_t reallocate(Handle handle, int16_t size)

Reallocate a region to a new size, copying data over.

Parameters:	handle - Region to resize. size - New size.
Returns:	SUCCESS if reallocated, FAIL otherwise.

lock

result_t lock(Handle handle)

Lock a memory region from being compacted. This is needed if pointers within it are passed around.

Parameters:	handle - Handle to region to lock.
Returns:	SUCCESS if locked successfuly, FAIL otherwise.

unlock

result_t unlock(Handle handle)

Unlock a memory region to allow its compaction.

Parameters:	handle - Handle to region to unlock.
Returns:	SUCCESS if unlocked successfuly, FAIL otherwise.

free

int16_t free(Handle handle)

Deallocate a memory region and return it to allocatable memory.

Parameters:	handle - Handle to region to free.
Returns:	Size of freed region.

compact

result_t compact(void)

Compact the allocated regions to prevent fragmentation.

Returns:

Whether the request to compact was accepted.

size

int16_t size(Handle handle)

Get the size of a memory region.

Parameters:	A - memory region.
Returns:	The region's size.

isLocked

bool isLocked(Handle handle)

Get whether a region is locked from compaction.

Parameters:	handle - The region to check.
Returns:	Whether the region is locked.

freeBytes

uint16_t freeBytes(void)

Return the number of free bytes available in the heap. This is the sum of all free blocks; even after compaction, a single block of this size may not be available if there are locked handles in the heap.

Returns:

The number of free bytes.

Events - Details

allocComplete

result_t allocComplete(HandlePtr handle, result_t success)

Signals when an allocation request has completed.

Parameters:	handle - The handle to the requested region. success - Whether the allocation was successful.
Returns:	Should always return SUCCESS.

reallocComplete

result_t reallocComplete(Handle handle, result_t success)

Signals when an reallocation request has completed.

Parameters:	handle - The handle to the requested region. success - Whether the reallocation was successful.
Returns:	Should always return SUCCESS.

compactComplete

result_t compactComplete(void)

Signals when a compaction request has completed.

Returns:

Should always return SUCCESS.