static UCHAR XmsAlloc(WORD Size, PWORD Handle)
{
BYTE i;
PXMS_HANDLE HandleEntry;
DWORD CurrentIndex = 0;
ULONG RunStart;
ULONG RunSize;
if (Size > FreeBlocks) return XMS_STATUS_OUT_OF_MEMORY;
for (i = 0; i < XMS_MAX_HANDLES; i++)
{
HandleEntry = &HandleTable[i];
if (HandleEntry->Handle == 0)
{
*Handle = i + 1;
break;
}
}
if (i == XMS_MAX_HANDLES) return XMS_STATUS_OUT_OF_HANDLES;
/* Optimize blocks */
for (i = 0; i < XMS_MAX_HANDLES; i++)
{
/* Skip free and locked blocks */
if (HandleEntry->Handle == 0 || HandleEntry->LockCount > 0) continue;
CurrentIndex = (HandleEntry->Address - XMS_ADDRESS) / XMS_BLOCK_SIZE;
/* Check if there is any free space before this block */
RunSize = RtlFindLastBackwardRunClear(&AllocBitmap, CurrentIndex, &RunStart);
if (RunSize == 0) break;
/* Move this block back */
RtlMoveMemory((PVOID)REAL_TO_PHYS(HandleEntry->Address - RunSize * XMS_BLOCK_SIZE),
(PVOID)REAL_TO_PHYS(HandleEntry->Address),
RunSize * XMS_BLOCK_SIZE);
/* Update the address */
HandleEntry->Address -= RunSize * XMS_BLOCK_SIZE;
}
while (CurrentIndex < XMS_BLOCKS)
{
RunSize = RtlFindNextForwardRunClear(&AllocBitmap, CurrentIndex, &RunStart);
if (RunSize == 0) break;
if (RunSize >= HandleEntry->Size)
{
/* Allocate it here */
HandleEntry->Handle = i + 1;
HandleEntry->LockCount = 0;
HandleEntry->Size = Size;
HandleEntry->Address = XMS_ADDRESS + RunStart * XMS_BLOCK_SIZE;
FreeBlocks -= Size;
RtlSetBits(&AllocBitmap, RunStart, HandleEntry->Size);
return XMS_STATUS_SUCCESS;
}
/* Keep searching */
CurrentIndex = RunStart + RunSize;
}
return XMS_STATUS_OUT_OF_MEMORY;
}
ULONG NtdllBitmap::FindLastBackwardRunClear( ULONG from_index, PULONG starting_run_index )
{
assert(RtlFindLastBackwardRunClear != NULL);
return RtlFindLastBackwardRunClear(this, from_index, starting_run_index);
}
