RAR Archive Format(rar.rfh):
Class: Archive, Status: Headers only, Last change: 21.01.2022 13:02:46

include DosFTime.rfi

TRARMagic array[7] of Char


0 TRARMagic Magic

  Magic='Rar!'#0x1A#7#0; //In fact it can be considered as a
    //special marker block, but this way it looks more natural


TBlockType enum byte (
  marker=0x72, //marker block
  archive=0x73, //archive header
  file=0x74, //file header
  comment=0x75, //comment header
  extra=0x76, //extra information
  subblock=0x77, //subblock
  recovery=0x78  //recovery record

type bit

TBit num+(1)
TBit3 num+(3)

TBit14 num+(14)

TArchiveFlags set 14 of (
  Volume ^ 0x01, // Volume attribute (archive volume)
  comment ^ 0x02, // Archive comment present
  lock ^ 0x04, // Archive lock attribute
  Solid ^ 0x08, // Solid attribute (solid archive)
  Auth ^ 0x20  // Authenticity information present

TDictKind enum TBit3 (
  Dict64K, //dictionary size   64 Kb
  Dict128K, //dictionary size  128 Kb
  Dict256K, //dictionary size  256 Kb
  Dict512K, //dictionary size  512 Kb
  Dict1024K, //dictionary size 1024 Kb
  Dir // file is directory

TFileFlagsF set 5 of (
  prev ^ 0x01, // file continued from previous volume
  next ^ 0x02, // file continued in next volume
  encrypt ^ 0x04, // file encrypted with password
  comment ^ 0x08, // file comment present
  solid ^ 0x10 // information from previous files is used (solid flag)
               //  (for RAR 2.0 and later)

TFileFlags struc
  TFileFlagsF F
  TDictKind Kind
  set 6 of () rest

TRARFlags(TP) struc
  case TBlockType @:TP of
    archive: TArchiveFlags
    file: TFileFlags
  else TBit14
  endc Spec //Type-Specific flags
  TBit OldIgnore //if set, older RAR versions will ignore the block
            //and remove it when the archive is updated.
            //if clear, the block is copied to the new archive
            //file when the archive is updated;
  TBit HasADD_SIZE //ADD_SIZE field is present and the full block
                   //size is HEAD_SIZE+ADD_SIZE.


//TRARBlock forward

TComment(On) forward

TMainHead(WithComment) struc
  word Rsrv1
  ulong Rsrv2
  TComment(@:WithComment) Comment

TOsCode enum byte (
  DOS=0, //MS DOS
  OS2=1, //OS/2

TRARMethod enum byte (
  storing=0x30, // storing
  fastest=0x31, // fastest compression
  fast=0x32, // fast compression
  normal=0x33, // normal compression
  good=0x34, // good compression
  best=0x35  // best compression

TFileHead(DataSz,WithComment) struc
  ulong UNP_SIZE  //Uncompressed file size
  TOsCode HOST_OS //Operating system used for archiving
  ulong FILE_CRC
  TFileTime FTIME //Date and time in standard MS DOS format
  byte UNP_VER    //RAR version needed to extract file
  TRARMethod METHOD     //Packing method
  word NAME_SIZE  //File name size
  ulong ATTR      //File attributes
  array[@.NAME_SIZE] of char FILE_NAME //File name - string of NAME_SIZE bytes size
  TComment(@:WithComment) Comment
  raw[@:DataSz] D

TCommentHead struc
  word UNP_SIZE //Uncompressed comment size
  byte UNP_VER //RAR version needed to extract comment
  TRARMethod METHOD //Packing method
  word COMM_CRC //Comment CRC
  array of Char COMMENT //Comment text

TRARBlock struc
  word CRC       //CRC of total block or block part
  TBlockType TYPE      //Block type
  TRARFlags(@.TYPE) FLAGS //Block flags
  word SIZE      //Block size
  case @.FLAGS.HasADD_SIZE of
   1: ulong
  endc ADD_SIZE //Optional field - added block size
  case @.TYPE of
    marker: void
    archive: TMainHead(@@.FLAGS.Spec.archive and TArchiveFlags.comment<>0)
    file: TFileHead(@@.ADD_SIZE.1 /*PACK_SIZE*/,
      @@.FLAGS.Spec.file.F and TFileFlagsF.comment<>0)
    comment: TCommentHead
  // extra: raw[]
  // subblock:
  // recovery:
  else raw[]
  endc D
ends:[@:Size=@.Size+((@.ADD_SIZE.1) exc 0)]

TComment(On) case @:On of
  1: TRARBlock
endc :assert[not @:On or(@.1.TYPE = TBlockType.comment)]

Magic:Size TRARBlock Hdr
Magic:Size+Hdr:Size array of TRARBlock:
  [@:Size=FileSize-(Magic:Size+Hdr:Size)] Files

assert Hdr:assert;

descr ('RAR Archive File Format.',NL,
  'Info Source: RAR version 2.02 - Technical information',NL,
  '  (rar202.zip at www.wotsit.org)',NL)

Other specifications.

FlexT home page, Author`s home page.