📄 ulist.pas
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unit UList;
interface
{$I types.inc}
type
PPListStruct = ^PListStruct;
PListStruct = ^TListStruct;
TListStruct = record
pNext: PListStruct;
pData: pointer;
ItemCount: dword;
end;
function IsAdded(List: PListStruct; Data: pointer): boolean;
procedure DelItem(var List: PListStruct; Data: pointer);
procedure DelItemAndFree(var List: PListStruct; Data: pointer);
procedure FreeList(var List: PListStruct);
procedure FreeListWidthData(var List: PListStruct);
procedure AddItem(var List: PListStruct; Data: pointer);
function GetItemData(List: PListStruct; ItemNum: dword): pointer;
implementation
function IsAdded(List: PListStruct; Data: pointer): boolean;
begin
Result := true;
while List <> nil do
begin
if Data = List^.pData then Exit;
List := List^.pNext
end;
Result := false;
end;
procedure DelItem(var List: PListStruct; Data: pointer);
var
Item, Prev: PListStruct;
Count: dword;
begin
Item := List;
if Item = nil then Exit;
Count := List^.ItemCount;
Prev := nil;
while Item <> nil do
begin
if Data = Item^.pData then
begin
if Prev <> nil then Prev^.pNext := Item^.pNext else List := Item^.pNext;
Exit;
end;
Prev := Item;
Item := Item^.pNext;
end;
List^.ItemCount := Count - 1;
end;
procedure DelItemAndFree(var List: PListStruct; Data: pointer);
begin
DelItem(List, Data);
FreeMem(Data);
end;
procedure FreeList(var List: PListStruct);
var
Mem: pointer;
begin
while List <> nil do
begin
Mem := List;
List := List^.pNext;
FreeMem(Mem);
end;
List := nil;
end;
procedure FreeListWidthData(var List: PListStruct);
var
Mem: pointer;
begin
while List <> nil do
begin
Mem := List;
FreeMem(List^.pData);
List := List^.pNext;
FreeMem(Mem);
end;
List := nil;
end;
procedure AddItem(var List: PListStruct; Data: pointer);
var
wNewItem: PListStruct;
begin
GetMem(wNewItem, SizeOf(TListStruct));
wNewItem^.pNext := List;
if List = nil then wNewItem^.ItemCount := 0
else wNewItem^.ItemCount := List^.ItemCount + 1;
wNewItem^.pData := Data;
List := wNewItem;
end;
function GetItemData(List: PListStruct; ItemNum: dword): pointer;
begin
Result := nil;
while List <> nil do
begin
if List^.ItemCount = ItemNum then
begin
Result := List^.pData;
Exit;
end;
List := List^.pNext;
end;
end;
end.
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