Delphi DLL

Demonstrates how to Handle Large Integers in JSON

See more JSON Examples

Demonstrates how to handle large integers in JSON. (Integers larger than what can fit in a 32-bit signed integer.) Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
json: HCkJsonObject;
id: Integer;
accountId: PWideChar;

begin
success := False;

// Let's say your JSON has this:

// {
// 	"id": 20000000001234567
// }

json := CkJsonObject_Create();

success := CkJsonObject_LoadFile(json,'qa_data/json/large_int.json');
if (success = False) then
  begin
    Memo1.Lines.Add(CkJsonObject__lastErrorText(json));
    Exit;
  end;

// The integer is too large for a 32-bit signed integer that is returned by IntOf.
// The result will be something that wrapped around and could be negative.
// In this case it would be: -543893881
id := CkJsonObject_IntOf(json,'id');
Memo1.Lines.Add('id: ' + IntToStr(id));

// The solution is to read the integer value as a string, and then use the features in your programming language
// to convert from a string to a 64-bit integer.
// 
// Alternatively, you may wish to simply hold the value as a string.  If, for example, the integer simply references
// an order ID, an account ID, etc., then there's no need to convert to an integer value.  You're not going to be doing
// mathematical operations on it anyway.  This is usually the case for large integers -- they typically exist
// in JSON as an account ID.

// You can get any JSON value as a string:
accountId := CkJsonObject__stringOf(json,'id');
Memo1.Lines.Add('accountId: ' + accountId);

// Sample output:

// id: -543893881
// accountId: 20000000001234567

CkJsonObject_Dispose(json);

end;