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IDProjectCategoryView StatusLast Update
0006637JEDI Code LibraryJclQueuespublic2018-06-05 09:57
ReportervirgoparnaAssigned To 
Status newResolutionopen 
Product Version 
Target VersionFixed in Version 
Summary0006637: JclQueue classes can have maximum capacity - 1 elements.
DescriptionI noticed, that when I create TJclQueue with capacity 1, then I can't enqueue any objects. And debugging it I discovered, that actual problem is in all queue classes and is, that if queue size equal to capacity - 1, then it can't add any more elements because it fails to grow.
Additional InformationFollowing sample program demonstrates the problem (program output will be:
Enqueueing HELLO failed
Enqueueing WORLD failed

program queue;
  JclContainerIntf, JclQueues;
  SQ: IJclStrQueue;
  SQ := TJclStrQueue.Create(1);
  if not SQ.Enqueue('HELLO') then
    writeln('Enqueueing HELLO failed')
    writeln('Enqueueing HELLO succeeded');
  if not SQ.Enqueue('WORLD') then
    writeln('Enqueueing WORLD failed')
    writeln('Enqueueing WORLD succeeded');

Simplest solution would be to override AutoGrow for all Queue classes as:
  //+ 1 is needed, because queue must be 1 larger
  if FHead > FTail then
    SetCapacity(CalcGrowCapacity(FCapacity, FCapacity - FHead + FTail +
1)) // looped
    SetCapacity(CalcGrowCapacity(FCapacity, FTail - FHead + 1));

Actually, all AbstractContainer methods using FSize will need overriding
because Queue classes do not use FSize and it is always 0. That is
separate issue.
TagsNo tags attached.
Fixed in GIT commit
Fixed in SVN revision
IDE versionAll


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Issue History

Date Modified Username Field Change
2018-06-05 09:57 virgoparna New Issue
2018-06-05 09:57 virgoparna IDE version => All