Amir via fpc-pascal <fpc-pascal@lists.freepascal.org> schrieb am Sa., 30. Dez. 2023, 08:11:
> > > On Dec 29, 2023 9:50 PM, Adriaan van Os <adri...@adriaan.biz> wrote: > > Amir--- via fpc-pascal wrote: > > Hi all, > > > > I have a List of record, where the record has a WideString field. > > I have some code like the following: > > > > function check(constref v: TMyRecord; data: TListOfMyRecord): Boolean; > > var > > r: TMyRecord; > > > > begin > > Result := False; > > for r in data do > > if r.State = v.State then > > Exit(True); > > end; > > > > I call this method a lot and the CPU profiling shows a lot of cpu time > > spent on "fpc_copy_proc" (which I assume is doing the deep copy on > > records) from "TCustomListEnumerator.GetCurrent". > > I considered other alternatives like using enumerators but they all need > > a to return a record (and hence copying the widestring field). > > I can think of two solutions to get rid of the wasting(!) so much time > > on "fpc_copy_proc": > > 1) Changing the TMyRecord to TMyClass. But then I need to Create and > > Free a "lot" of objects. > > 2) Update TListOfMyRecord to TListOfPointerToMyRecord. This requires a > > "lot" of memory allocation/fragmentation. > > > > Is there a better solution? > > Pass the data parameter by reference. > > This means I need to have a ListOfMyRecord and a ListOfConstRefMyRecord, > right? > No, that's not a thing. You simply need to declare your "data" parameter as "constref" or "const" as well, just like your "v" parameter. Note: prefer the use of "const" instead of "constref" unless you really need a reference, because the compiler will then pick the optimal way to pass the value (e.g. small ones will be passed by register instead of as an address). Regards, Sven >
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