static void CreatePage(Native aItemSize)
{
if (aItemSize == 0)
{
throw new Exception("ItemSize cannot be 0.");
}
else if (aItemSize % sizeof(Native) != 0)
{
throw new Exception("Item size must be word aligned.");
}
else if (mMaxItemSize == 0)
{
throw new Exception("SMT is not initialized.");
}
else if (aItemSize > mMaxItemSize)
{
throw new Exception("Cannot allocate more than MaxItemSize in SmallHeap.");
}
var xPtr = (Native *)RAT.Alloc(RAT.PageType.HeapSmall);
*xPtr = 0;
for (void **p = mSMT + aItemSize; ; p--)
{
// TODO - Make a free list, put a ptr in item header and first page header - how to keep compact?
}
// Header
// Ptr to next page of same size
// Each Item
//xPtr[0] = aSize; // Actual data size
//xPtr[1] = 0; // Ref count
//xPtr[2] = 0; // Ptr to first
}
static void InitSMT(Native aMaxItemSize)
{
mMaxItemSize = aMaxItemSize;
Native xPageCount = mMaxItemSize * (Native)sizeof(void *) / RAT.PageSize;
mSMT = (void **)RAT.Alloc(RAT.PageType.HeapSmall, xPageCount);
}
static public byte *Alloc(Native aSize)
{
Native xPages = (Native)((aSize + PrefixBytes) / RAT.PageSize) + 1;
var xPtr = (Native *)RAT.Alloc(RAT.PageType.HeapLarge, xPages);
xPtr[0] = xPages * RAT.PageSize - PrefixBytes; // Allocated data size
xPtr[1] = aSize; // Actual data size
xPtr[2] = 0; // Ref count
xPtr[3] = 0; // Ptr to first
return((byte *)xPtr + PrefixBytes);
}