heap object

Peter Verkaik

Attached are a heap object and test program.
This provides dynamic memory use. Blocks can be allocated and freed in any order.
Support methods to check heap integrity,·retrieving length of allocated blocks,
retrieving length of largest free block.

regards peter

Post Edited (Peter Verkaik) : 1/2/2008 8:14:46 PM GMT

stevenmess2004

Now all that we need is the ability to dynamically load spin programs.

Steven

Peter Verkaik

Minor update to make it easier to support heaps in heap.
I added the method heap that returns the base address of the heap.

·* Example:
·* OBJ
·*·· hp1: "heap"
·*·· hp2: "heap"
·* VAR
·*·· byte heapArray[noparse][[/noparse]1024]·········· 'heapArray will be used to hold a heap
·*·· word block
·* PUB
·*·· hp1.create(@heapArray,1024)··· 'create heap with size 1024 bytes
·*·· if (hp1.available => 120)
·*···· block := hp1.allocate(120)·· 'allocate a block of 120 bytes
·*···· 'do something with block
·*···· hp1.free(block)
·*·· else
·*···· 'error No block allocated
·*
·* It is possible to create a heap inside a heap.
·* Example:
·*·· hp1.create(@heapArray,1024)
·*·· block := hp1.allocate(120)·········· 'allocate a block
·*·· hp2.create(block,hp1.length(block)) 'convert block to heap
·* This is useful if a task must keep track of multiple blocks (from heap hp2) but the task may be aborted.
·* In that case a single call to free will free all blocks allocated from heap hp2.
·*·· hp1.free(hp2.heap)
·*

regards peter

Nick Mueller

Oh, and today I thought about heaps.
But now ...

Thanks!

Nick

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stevenmess2004

Peter, is it alright if I use this in DOL?

Steven

Peter Verkaik

Sure. The heap object is·intended to be initialized from the top object.
(by calling create). By declaring it also in OBJ in other objects, these
objects can also allocate and free blocks of memory. Note that there
currently is no lock used in the heap object but that is easily added.
Point of concern: what if a dynamically loaded object also makes
use of the heap object? When unloading such an object it should free
its allocated blocks before it unloads, but I guess the stop method
of that object can do that (so unload calls stop first). The memory
used to store the object itself is of course freed by DOL.

regards peter

stevenmess2004

Thats the idea Peter. Thanks for permission.

Steven

Phil Pilgrim (PhiPi)

Steven,

Here is another heap manager object for you to try, if you need one with locking built-in. Also included in the zip is a dynamic strings object, which demostrates how to use the heap manager.

-Phil

stevenmess2004

Thanks Phil