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Dennis · Guest

Hi

Could somebody review this new validation function?

//Grow dynamic array with STEPSIZE from MIN to MAX and validate that it is 4
byte aligned

function TMMValidation.Validate22 : Boolean;
var
SomeArray : array of Byte;
MemoryStatus : TMemoryStatus;
BytesToAllocate, StartAddress, I2, I3, OldBytesToAllocate : Cardinal;
const
BYTESTOALLOCATESTEPSIZE : Cardinal = 2;
BYTESTOALLOCATEMIN : Cardinal = 5;//5 byte
BYTESTOALLOCATEMAX : Cardinal = 50*1024*1024;//50 Mbyte
FILLBYTE : Byte = 255;

begin
try
Result := True;
OldBytesToAllocate := 1;
//Allocate
SetLength(SomeArray, 1);
SomeArray[0] := FILLBYTE;
BytesToAllocate := BYTESTOALLOCATEMIN;
while BytesToAllocate <= BYTESTOALLOCATEMAX do
begin
GlobalMemoryStatus(MemoryStatus);
if MemoryStatus.dwAvailVirtual >= BytesToAllocate then
begin
//Reallocate
SetLength(SomeArray, BytesToAllocate);
//Old data preserved?
for I3 := 0 to OldBytesToAllocate-1 do
begin
if SomeArray[I3] <> FILLBYTE then
begin
Result := False;
Exit;
end;
end;
//4 byte alignment?
//Add 8 byte offset to compensate for refcount and size data
StartAddress := Cardinal(@SomeArray[8]);
if StartAddress mod 4 <> 0 then
begin
Result := False;
Exit;
end;
//Fill newly allocated space
for I2 := OldBytesToAllocate to BytesToAllocate-1 do
SomeArray[I2] := FILLBYTE;
OldBytesToAllocate := BytesToAllocate;
BytesToAllocate := BytesToAllocate * BYTESTOALLOCATESTEPSIZE;
end;
end;
//Free
SetLength(SomeArray, 0);
except
Result := False;
end;
end;

Regards
Dennis