internal static unsafe FreeNode *Create(PhysicalHeap *inHeap,
UIntPtr addr, UIntPtr pages)
{
DebugStub.Assert(addr >= inHeap->startAddr);
DebugStub.Assert((addr + (pages * MemoryManager.PageSize)) <= inHeap->heapLimit);
FreeNode *node = (FreeNode *)addr;
// This had better be a free page in the main table
DebugStub.Assert(inHeap->PageWord(inHeap->PageIndex(addr)) == FreePage,
"Creating a FreeNode for non-free page {0:x}",
__arglist(addr));
node->signature = FreeNode.Signature;
node->bytes = pages * MemoryManager.PageSize;
node->prev = null;
node->next = null;
node->last = null;
if (pages > 1)
{
node->last = LastNode.Create(inHeap, addr, node);
}
return(node);
}
internal static unsafe LastNode *Create(PhysicalHeap *inHeap,
UIntPtr addr, FreeNode *node)
{
LastNode *last = (LastNode *)(addr + node->bytes - MemoryManager.PageSize);
DebugStub.Assert((UIntPtr)last >= inHeap->startAddr);
DebugStub.Assert((UIntPtr)last <= inHeap->heapLimit);
DebugStub.Assert(MemoryManager.IsPageAligned((UIntPtr)last));
last->signature = LastNode.Signature;
last->node = node;
return(last);
}
internal unsafe void CreateAndInsert(PhysicalHeap *inHeap,
UIntPtr addr,
UIntPtr pages)
{
DebugStub.Assert(MemoryManager.IsPageAligned(addr),
"PhysicalHeap.CreateAndInsert non page-aligned addr={0:x}",
__arglist(addr));
FreeNode *node = FreeNode.Create(inHeap, addr, pages);
DebugStub.Assert(MemoryManager.IsPageAligned(node->bytes),
"PhysicalHeap.CreateAndInsert non page-sized node->bytes={0:x}",
__arglist(node->bytes));
InsertBySize(node);
}
internal static unsafe FreeNode *GetNodeFromLast(PhysicalHeap *inHeap,
UIntPtr addr)
{
UIntPtr idx = inHeap->PageIndex(addr);
// addr must specify a free page
if (inHeap->PageWord(idx) != FreePage)
{
// addr does not specify a LastNode
return(null);
}
// addr must specify a page such that the next page (if there
// is one) is not free
if ((idx != inHeap->pageCount - 1) &&
(inHeap->PageWord(idx + 1) == FreePage))
{
return(null);
}
if (idx == 0)
{
// This is a one-page block
DebugStub.Assert(((FreeNode *)addr)->signature == FreeNode.Signature);
return((FreeNode *)addr);
}
// If the preceding page is free, then addr specifies
// the last page in a multi-page block, otherwise it
// specifies the only page in a one-page block.
if (inHeap->PageWord(idx - 1) == FreePage)
{
DebugStub.Assert(((LastNode *)addr)->signature == Signature);
return(((LastNode *)addr)->node);
}
else
{
DebugStub.Assert(((FreeNode *)addr)->signature == FreeNode.Signature);
return((FreeNode *)addr);
}
}
internal static unsafe FreeNode *GetNodeAt(PhysicalHeap *inHeap,
UIntPtr addr)
{
UIntPtr idx = inHeap->PageIndex(addr);
if (inHeap->PageWord(idx) != FreePage)
{
// This address designates a page that is in use.
return(null);
}
if ((idx > 0) && (inHeap->PageWord(idx - 1) == FreePage))
{
// This address is in the middle of a free block; it does
// not designate the beginning of a free block.
return(null);
}
DebugStub.Assert(((FreeNode *)addr)->signature == Signature);
return((FreeNode *)addr);
}