折半查找

function GetNodeUseXxh(const List: TList; const XXH: Integer): pCommonXXHandListNode;
//使用折半法查找节点
var
  Low, High, Mid: Integer;
  pnode: pCommonXXHandListNode;
begin
  Result := nil;
  Low := 0;
  High := List.count - 1;
  while (Low <= High) do begin
    Mid := (Low + High) div 2;
    pnode := pCommonXXHandListNode(List.Items[Mid]);
    if pnode^.XXH = XXH then begin
      Result := pnode;
      Break;
    end
    else if pnode^.XXH > XXH then begin
      High := Mid - 1;
    end
    else
      Low := Mid + 1;
  end;
end;