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  • kbmmemtable sorton 报错 : List index out of bounds

    同一数据集,不同的排序条件,有的可以,但某一条件,却能100%重现报错。

    procedure TkbmIndex.InternalFastQuickSort(const L,R:Integer);
    var
       I,J:integer;
       P:PkbmRecord;
    begin
         if ((R-L)>4) then
    //     if ((R-L)>0) then
         begin
              I:=(R+L) div 2;
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[L]),PkbmRecord(FReferences[I]),true,false)>0 then
               InternalSwap(L,I);
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[L]),PkbmRecord(FReferences[R]),true,false)>0 then
               InternalSwap(L,R);
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[I]),PkbmRecord(FReferences[R]),true,false)>0 then
               InternalSwap(I,R);
    
              J:=R-1;
              InternalSwap(I,J);
              I:=L;
              P:=PkbmRecord(FReferences[J]);
              while true do
              begin
                   Inc(I);
                   Dec(J);
                   while CompareRecords(FIndexFieldList,PkbmRecord(FReferences[I]),P,true,false) < 0 do Inc(I);
                   while CompareRecords(FIndexFieldList,PkbmRecord(FReferences[J]),P,true,false) > 0 do Dec(J);
                   if (J<I) then break;
                   InternalSwap(I,J);
              end;
              InternalSwap(I,R-1);
              InternalFastQuickSort(L,J);
              InternalFastQuickSort(I+1,R);
         end;
    end;

     反复跟代码,发现在  kbmMemTable.PAS中,当J减至0时,FReferences[J] 下标越界

    试改为FIndexFieldList.Count>0前判断条件却未解决,说明并非是递减原因,改为大于J,未报错,是否有问题,待应用中再关注。

    procedure TkbmIndex.InternalFastQuickSort(const L,R:Integer);
    var
       I,J:integer;
       P:PkbmRecord;
    begin
         if ((R-L)>4) then
    //     if ((R-L)>0) then
         begin
              I:=(R+L) div 2;
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[L]),PkbmRecord(FReferences[I]),true,false)>0 then
               InternalSwap(L,I);
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[L]),PkbmRecord(FReferences[R]),true,false)>0 then
               InternalSwap(L,R);
              if CompareRecords(FIndexFieldList,PkbmRecord(FReferences[I]),PkbmRecord(FReferences[R]),true,false)>0 then
               InternalSwap(I,R);
    
              J:=R-1;
              InternalSwap(I,J);
              I:=L;
              P:=PkbmRecord(FReferences[J]);
              while true do
              begin
                   Inc(I);
                   Dec(J);
                   while CompareRecords(FIndexFieldList,PkbmRecord(FReferences[I]),P,true,false) < 0 do Inc(I);
                   while  (FIndexFieldList.Count>J )and (CompareRecords(FIndexFieldList,PkbmRecord(FReferences[J]),P,true,false) > 0) do Dec(J);
                   if (J<I) then break;
                   InternalSwap(I,J);
              end;
              InternalSwap(I,R-1);
              InternalFastQuickSort(L,J);
              InternalFastQuickSort(I+1,R);
         end;
    end;
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  • 原文地址:https://www.cnblogs.com/zhqian/p/10495329.html
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