Store1.pas

   1 UNIT Store1;
   2 {Take tracks of files in store}
   3 {just simple, no cleaning, etc}
   4 INTERFACE
   5 uses SysUtils;
   6
   7 type
   8 tfid=array [0..19] of byte;
   9 tStoreObjectInfo=object
  10  final:boolean;    {hash matched}
  11  rc:Word; {0=no error 1=not found, other}
  12  length:LongWord;  {the whole file}
  13  seglen:longword;  {from cur to end of segment}
  14
  15  procedure Open(const fid:tfid);
  16  procedure Close;
  17  procedure SegSeek(ofs:LongWord); unimplemented;
  18  procedure ReadAhead(cnt:Word; into:pointer);
  19  procedure WaitRead; {wait for read to finish, rc}
  20  private
  21  dh:tHandle; {handle to the data file}
  22  filename:string[80];
  23  procedure mkfilen(var d:string; flag:char; const fid:tfid);
  24 end;
  25
  26 IMPLEMENTATION
  27 const prefix='object';
  28
  29 procedure tStoreObjectInfo.mkfilen(var d:string; flag:char; const fid:tfid);
  30  function hc(b:byte):char;
  31   begin
  32   if b<10 then hc:=char(ord('0')+b)
  33           else hc:=char(ord('A')-10+b);
  34   end;
  35  var b,i:byte;
  36  begin
  37  d:=prefix+flag+'/';
  38  b:=system.length(d);
  39  SetLength(d,b+40);
  40  inc(b);
  41  for i:=0 to 19 do begin
  42   filename[b+(i*2)]:=hc(fid[i] shr 4);
  43   filename[b+(i*2)+1]:=hc(fid[i] and $F);
  44  end;
  45 end;
  46 procedure tStoreObjectInfo.Open(const fid:tfid);
  47  begin
  48  mkfilen(filename,'f',fid);
  49  dh:=FileOpen(filename,fmOpenRead or fmShareDenyWrite);
  50  if dh<>-1 then begin
  51   rc:=0;
  52   final:=true;
  53   length:=FileSeek(dh,0,fsFromEnd);
  54   FileSeek(dh,0,fsFromBeginning);
  55  end else begin
  56   Writeln('Store1: open failed for file ',filename,', ioresult=',IOResult);
  57   rc:=2;
  58  end;
  59 end;
  60 procedure tStoreObjectInfo.ReadAhead(cnt:Word; into:pointer);
  61  var red:LongWord;
  62  begin
  63  //todo, do real async read
  64  red:=FileRead(dh,into^,cnt);
  65  if red=cnt then rc:=0 else begin
  66   //todo
  67   writeln('Store1: read ',red,' out of ',cnt,' requested bytes');
  68   rc:=2;
  69  end;
  70 end;
  71 procedure tStoreObjectInfo.WaitRead; {wait for read to finish, rc}
  72  begin
  73  //todo
  74 end;
  75 procedure tStoreObjectInfo.Close;
  76  begin
  77  FileClose(dh);
  78 end;
  79 procedure tStoreObjectInfo.SegSeek(ofs:longword);
  80  begin
  81  if ofs=0 then begin
  82  rc:=0;
  83  seglen:=length;
  84  end else rc:=7;
  85 end;
  86
  87 END.
  88