#1 2024-06-27 03:07:55

idigger
Member
Registered: 2022-11-05
Posts: 6

DynArrayLoadJson does not work like Delphi in FPC

System Information
- Operating system: Windows
- Processor architecture: x86-64
- Device: Computer
- FPC version: 3.3.1 [2024/06/26] for i386, Trunk 0c745fb257
- mORMot2 version: master 70e2e9ce

Example Project

program project1;

{$ifdef FPC}
{$mode delphi}
{$else}
{$APPTYPE CONSOLE}
{$endif}

{$I mormot.defines.inc}

uses
  {$I mormot.uses.inc}
  {$IFDEF DCC}System.{$ENDIF}Classes, {$IFDEF DCC}System.{$ENDIF}SysUtils,
  mormot.core.base,
  mormot.core.rtti,
  mormot.core.variants,
  mormot.core.json;

type

  {$RTTI EXPLICIT PROPERTIES([vcPublished]) FIELDS([vcPublic]) METHODS([])}

  TEFloor = packed record
    el: WORD;
    fl: array of Byte;
  end;

  TECtrl = packed record
    ecid: WORD;
    expd: array of Byte;
    efl: array of TEFloor;
    icod: UTF8String;
    pt: array of Integer;
    adv: BYTE;
  end;
  TECtrls = Array of TECtrl;

var
  tmp1, tmp2: UTf8String;
  ec: TECtrls;
begin
  tmp1 := '[{"ecid":12,"expd":[80,17,18],"efl":[{"el":0,"fl":[1,2]},{"el":1,"fl":[4,5]}],"icod":"123456","pt":[1,2,3],"adv":5}]';
  DynArrayLoadJson(ec, tmp1, TypeInfo(TECtrls));
  WriteLn(tmp1);

  tmp2 := DynArraySaveJson(ec, TypeInfo(TECtrls));
  WriteLn(tmp2);

  if tmp1 = tmp2 then WriteLn('ok')
  else                WriteLn('failed');

end.

The above programs are compiled with fpc and run as follows.

# fpc project1.pas -Fic:\mORMot2\src -Fuc:\mORMot2\src\core;c:\mORMot2\src\lib -Flc:\mORMot2\static\i386-win32
Free Pascal Compiler version 3.3.1 [2024/06/26] for i386
Copyright (c) 1993-2024 by Florian Klaempfl and others
Target OS: Win32 for i386
Compiling project1.pas
Linking project1.exe
895 lines compiled, 0.3 sec, 563504 bytes code, 20004 bytes data

# project1
[{"ecid":12,"expd":[80,17,18],"efl":[{"el":0,"fl":[1,2]},{"el":1,"fl":[4,5]}],"icod":"123456","pt":[1,2,3],"adv":5}]
[]
failed

Relevant 3rd party information

The above program is compiled by delphi and the results are as follows

# dcc32 project1.pas -Ic:\mORMot2\src;c:\mORMot2\static\i386-win32 -Uc:\mORMot2\src\core;c:\mORMot2\src\lib -NSSystem;Winapi
Embarcadero Delphi for Win32 compiler version 36.0
Copyright (c) 1983,2024 Embarcadero Technologies, Inc.
c:\mORMot2\src\mormot.defines.inc(792)
c:\mORMot2\src\mormot.uses.inc(50)
project1.pas(56)
897 lines, 0.11 seconds, 1439256 bytes code, 103032 bytes data.

# project1.exe
[{"ecid":12,"expd":[80,17,18],"efl":[{"el":0,"fl":[1,2]},{"el":1,"fl":[4,5]}],"icod":"123456","pt":[1,2,3],"adv":5}]
[{"ecid":12,"expd":[80,17,18],"efl":[{"el":0,"fl":[1,2]},{"el":1,"fl":[4,5]}],"icod":"123456","pt":[1,2,3],"adv":5}]
ok

I know that using RegisterType and RegisterFromText can solve this problem,

But the latest FPC has supported RTTI record (https://gitlab.com/freepascal.org/fpc/s … sues/40798)

Just request improvements to mORMot2 DynArrayLoadJson in FPC.
May mORMot2 get better and better!

Last edited by idigger (2024-06-27 16:01:04)

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#2 2024-06-27 07:44:56

ab
Administrator
From: France
Registered: 2010-06-21
Posts: 14,371
Website

Re: DynArrayLoadJson does not work like Delphi in FPC

I have just added experimental support for this trunk feature.
Feedback is welcome!

See your https://github.com/synopse/mORMot2/issues/266 entry.

No need to copy everything from github in this forum if you already have enough information there.

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#3 2024-06-27 10:26:52

idigger
Member
Registered: 2022-11-05
Posts: 6

Re: DynArrayLoadJson does not work like Delphi in FPC

project1.pas adds the following statement before TEFloor = packed record.

{$RTTI EXPLICIT
PROPERTIES([vcPublished])
FIELDS([vcPublic])
METHODS([])}

Recompile and run, everything is fine.

You were amazing.

Thank you for your quick response and quick repair.

Last edited by idigger (2024-06-27 10:37:22)

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#4 2024-06-27 11:57:50

ab
Administrator
From: France
Registered: 2010-06-21
Posts: 14,371
Website

Re: DynArrayLoadJson does not work like Delphi in FPC

This is weird that we need an $RTTI EXPLICIT on FPC, because on Delphi, we don't need this statement.
My guess is that it should be reported to the FPC compiler team.

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#5 2024-06-27 14:21:54

idigger
Member
Registered: 2022-11-05
Posts: 6

Re: DynArrayLoadJson does not work like Delphi in FPC

After testing, delphi enables rtti record by default, and fpc is off by default.
Replace {$RTTI EXPLICIT PROPERTIES([vcPublished]) FIELDS([]) PROPERTIES([])} with {$RTTI EXPLICIT METHODS([]) FIELDS([vcPublic]) METHODS([])},
project.pas compiled by delphi and the results also failed.

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#6 2024-06-27 15:40:40

ab
Administrator
From: France
Registered: 2010-06-21
Posts: 14,371
Website

Re: DynArrayLoadJson does not work like Delphi in FPC

I also guess that {$modeswitch advancedrecords} is not needed for having extended RTTI available.

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#7 2024-06-27 16:00:00

idigger
Member
Registered: 2022-11-05
Posts: 6

Re: DynArrayLoadJson does not work like Delphi in FPC

yes, {$modeswitch advancedrecords} is not needed.

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