dos_compilers/Borland Turbo Pascal v55/OBJECTS.PAS
2024-07-02 06:49:04 -07:00

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{ Turbo Objects }
{ Copyright (c) 1989 by Borland International, Inc. }
unit Objects;
{ Turbo Pascal 5.5 object-oriented example.
This unit defines some basic object types.
Refer to OOPDEMOS.DOC for an overview of this unit.
}
{$S-}
interface
const
{ Stream access modes }
SCreate = $3C00; { Create new file }
SOpenRead = $3D00; { Read access only }
SOpenWrite = $3D01; { Write access only }
SOpen = $3D02; { Read and write access }
{ SetPos positioning modes }
PosAbs = 0; { Relative to beginning }
PosCur = 1; { Relative to current position }
PosEnd = 2; { Relative to end }
type
{ General conversion types }
WordRec = record
Lo, Hi: Byte;
end;
LongRec = record
Lo, Hi: Word;
end;
PtrRec = record
Ofs, Seg: Word;
end;
{ Abstract base object type }
BasePtr = ^Base;
Base = object
destructor Done; virtual;
end;
{ Stream type list }
STypeListPtr = ^STypeList;
STypeList = array[1..256] of Word;
{ Stream I/O procedure record }
SProc = object
StoreProc: Pointer;
LoadProc: Pointer;
end;
{ Stream I/O procedure list }
SProcListPtr = ^SProcList;
SProcList = array[1..256] of SProc;
{ Abstract stream object type }
StreamPtr = ^Stream;
Stream = object(Base)
TypeCount: Word;
TypeList: STypeListPtr;
ProcList: SProcListPtr;
Status: Integer;
constructor Init;
destructor Done; virtual;
procedure Error(Code: Integer); virtual;
procedure Flush; virtual;
function GetPos: Longint; virtual;
procedure Read(var Buf; Count: Word); virtual;
procedure RegisterTypes; virtual;
procedure SetPos(Pos: Longint; Mode: Byte); virtual;
procedure Truncate; virtual;
procedure Write(var Buf; Count: Word); virtual;
function Get: BasePtr;
function GetSize: Longint;
procedure Put(B: BasePtr);
procedure Register(TypePtr, StorePtr, LoadPtr: Pointer);
procedure Seek(Pos: Longint);
end;
{ DOS file name string }
FNameStr = string[79];
{ Unbuffered DOS stream }
DosStreamPtr = ^DosStream;
DosStream = object(Stream)
Handle: Word;
constructor Init(FileName: FNameStr; Mode: Word);
destructor Done; virtual;
function GetPos: Longint; virtual;
procedure Read(var Buf; Count: Word); virtual;
procedure SetPos(Pos: Longint; Mode: Byte); virtual;
procedure Truncate; virtual;
procedure Write(var Buf; Count: Word); virtual;
procedure Close;
procedure Open(var Name; Mode: Word);
end;
{ Buffered DOS stream }
BufStreamPtr = ^BufStream;
BufStream = object(DosStream)
Buffer: Pointer;
BufSize: Word;
BufPtr: Word;
BufEnd: Word;
constructor Init(FileName: FNameStr; Mode, Size: Word);
destructor Done; virtual;
procedure Flush; virtual;
function GetPos: Longint; virtual;
procedure Read(var Buf; Count: Word); virtual;
procedure Write(var Buf; Count: Word); virtual;
end;
{ Abstract linked list node type }
NodePtr = ^Node;
Node = object(Base)
Next: NodePtr;
function Prev: NodePtr;
end;
{ Linked list type }
ListPtr = ^List;
List = object
Last: NodePtr;
procedure Append(N: NodePtr);
procedure Clear;
procedure Delete;
function Empty: Boolean;
function First: NodePtr;
procedure Insert(N: NodePtr);
procedure Load(var S: Stream);
function Next(N: NodePtr): NodePtr;
function Prev(N: NodePtr): NodePtr;
procedure Remove(N: NodePtr);
procedure Store(var S: Stream);
end;
{ Abstract notification procedure }
procedure Abstract;
implementation
{$L STREAM} { Stream externals }
{$L DOSSTM} { DosStream externals }
{$L BUFSTM} { BufStream externals }
procedure StreamError; external {STREAM};
{ Base }
destructor Base.Done;
begin
end;
{ Stream }
constructor Stream.Init;
begin
TypeCount := 0;
TypeList := nil;
ProcList := nil;
Status := 0;
RegisterTypes;
GetMem(TypeList, TypeCount * SizeOf(Word));
if TypeList = nil then Fail;
GetMem(ProcList, TypeCount * SizeOf(SProc));
if ProcList = nil then
begin
FreeMem(TypeList, TypeCount * SizeOf(Word));
Fail;
end;
TypeCount := 0;
RegisterTypes;
end;
destructor Stream.Done;
begin
FreeMem(ProcList, TypeCount * SizeOf(SProc));
FreeMem(TypeList, TypeCount * SizeOf(Word));
end;
procedure Stream.Error(Code: Integer);
begin
Status := Code;
end;
procedure Stream.Flush;
begin
end;
function Stream.GetPos: Longint;
begin
Abstract;
end;
procedure Stream.Read(var Buf; Count: Word);
begin
Abstract;
end;
procedure Stream.RegisterTypes;
begin
end;
procedure Stream.SetPos(Pos: Longint; Mode: Byte);
begin
Abstract;
end;
procedure Stream.Truncate;
begin
Abstract;
end;
procedure Stream.Write(var Buf; Count: Word);
begin
Abstract;
end;
function Stream.Get: BasePtr;
external {STREAM};
function Stream.GetSize: Longint;
var
P: Longint;
begin
P := GetPos;
SetPos(0, PosEnd);
GetSize := GetPos;
SetPos(P, PosAbs);
end;
procedure Stream.Put(B: BasePtr);
external {STREAM};
procedure Stream.Register(TypePtr, StorePtr, LoadPtr: Pointer);
begin
Inc(TypeCount);
if TypeList <> nil then
begin
TypeList^[TypeCount] := PtrRec(TypePtr).Ofs;
with ProcList^[TypeCount] do
begin
StoreProc := StorePtr;
LoadProc := LoadPtr;
end;
end;
end;
procedure Stream.Seek(Pos: Longint);
begin
SetPos(Pos, PosAbs);
end;
{ DosStream }
constructor DosStream.Init(FileName: FNameStr; Mode: Word);
var
L: Integer;
begin
if not Stream.Init then Fail;
L := Length(FileName);
Move(FileName[1], FileName[0], L);
FileName[L] := #0;
Open(FileName, Mode);
end;
destructor DosStream.Done;
begin
Close;
Stream.Done;
end;
function DosStream.GetPos: Longint;
external {DOSSTM};
procedure DosStream.Read(var Buf; Count: Word);
external {DOSSTM};
procedure DosStream.SetPos(Pos: Longint; Mode: Byte);
external {DOSSTM};
procedure DosStream.Truncate;
external {DOSSTM};
procedure DosStream.Write(var Buf; Count: Word);
external {DOSSTM};
procedure DosStream.Close;
external {DOSSTM};
procedure DosStream.Open(var Name; Mode: Word);
external {DOSSTM};
{ BufStream }
constructor BufStream.Init(FileName: FNameStr; Mode, Size: Word);
begin
GetMem(Buffer, Size);
if Buffer = nil then Fail;
if not DosStream.Init(FileName, Mode) then
begin
FreeMem(Buffer, Size);
Fail;
end;
BufSize := Size;
BufPtr := 0;
BufEnd := 0;
end;
destructor BufStream.Done;
begin
DosStream.Done;
FreeMem(Buffer, BufSize);
end;
procedure BufStream.Flush;
external {BUFSTM};
function BufStream.GetPos: Longint;
external {BUFSTM};
procedure BufStream.Read(var Buf; Count: Word);
external {BUFSTM};
procedure BufStream.Write(var Buf; Count: Word);
external {BUFSTM};
{ Node }
function Node.Prev: NodePtr;
var
P: NodePtr;
begin
P := @Self;
while P^.Next <> @Self do P := P^.Next;
Prev := P;
end;
{ List }
procedure List.Append(N: NodePtr);
begin
Insert(N);
Last := N;
end;
procedure List.Clear;
begin
Last := nil;
end;
procedure List.Delete;
var
P: NodePtr;
begin
while not Empty do
begin
P := First;
Remove(P);
Dispose(P, Done);
end;
end;
function List.Empty: Boolean;
begin
Empty := Last = nil;
end;
function List.First: NodePtr;
begin
if Last = nil then First := nil else First := Last^.Next;
end;
procedure List.Insert(N: NodePtr);
begin
if Last = nil then Last := N else N^.Next := Last^.Next;
Last^.Next := N;
end;
procedure List.Load(var S: Stream);
var
P: NodePtr;
begin
Clear;
P := NodePtr(S.Get);
while P <> nil do
begin
Append(P);
P := NodePtr(S.Get);
end;
end;
function List.Next(N: NodePtr): NodePtr;
begin
if N = Last then Next := nil else Next := N^.Next;
end;
function List.Prev(N: NodePtr): NodePtr;
begin
if N = First then Prev := nil else Prev := N^.Prev;
end;
procedure List.Remove(N: NodePtr);
var
P: NodePtr;
begin
if Last <> nil then
begin
P := Last;
while (P^.Next <> N) and (P^.Next <> Last) do P := P^.Next;
if P^.Next = N then
begin
P^.Next := N^.Next;
if Last = N then if P = N then Last := nil else Last := P;
end;
end;
end;
procedure List.Store(var S: Stream);
var
P: NodePtr;
begin
P := First;
while P <> nil do
begin
S.Put(P);
P := Next(P);
end;
S.Put(nil);
end;
procedure Abstract;
begin
RunError(211);
end;
end.