Delphi:用于大文件(100MB)的sha256的快速流

uses
  System.Classes, System.SysUtils, System.Hash;

function CalculateSHA256(const FileName: string): string;
var
  FileStream: TFileStream;
  SHA256: THashSHA2;
  Buffer: TBytes;
  BytesRead: Integer;
begin
  FileStream := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite);
  try
    SHA256 := THashSHA2.Create;
    try
      SetLength(Buffer, 8192); // 设置缓冲区大小
      repeat
        BytesRead := FileStream.Read(Buffer[0], Length(Buffer));
        SHA256.Update(Buffer, BytesRead);
      until BytesRead = 0;
      Result := SHA256.HashAsString;
    finally
      SHA256.Free;
    end;
  finally
    FileStream.Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  FileName: string;
  SHA256Hash: string;
begin
  FileName := 'path_to_large_file';
  SHA256Hash := CalculateSHA256(FileName);
  ShowMessage('SHA256 Hash: ' + SHA256Hash);
end;