header.txt

   1 /*
   2  * Generic (MS-DOS style) time stamp format (localtime):
   3  *
   4  *  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
   5  * |<---- year-1980 --->|<- month ->|<--- day ---->|
   6  *
   7  *  15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
   8  * |<--- hour --->|<---- minute --->|<- second/2 ->|
   9  *
  10  */
  11
  12 /*
  13  * extended header
  14  *
  15  *             size  field name
  16  *  --------------------------------
  17  *  base header:         :
  18  *           2 or 4  next-header size  [*1]
  19  *  --------------------------------------
  20  *  ext header:   1  ext-type            ^
  21  *                ?  contents            | [*1] next-header size
  22  *           2 or 4  next-header size    v
  23  *  --------------------------------------
  24  *
  25  *  on level 1, 2 header:
  26  *    size field is 2 bytes
  27  *  on level 3 header:
  28  *    size field is 4 bytes
  29  */
  30
  31 /*
  32  * level 0 header
  33  *
  34  *
  35  * offset  size  field name
  36  * ----------------------------------
  37  *     0      1  header size    [*1]
  38  *     1      1  header sum
  39  *            ---------------------------------------
  40  *     2      5  method ID                         ^
  41  *     7      4  packed size    [*2]               |
  42  *    11      4  original size                     |
  43  *    15      2  time                              |
  44  *    17      2  date                              |
  45  *    19      1  attribute                         | [*1] header size (X+Y+22)
  46  *    20      1  level (0x00 fixed)                |
  47  *    21      1  name length                       |
  48  *    22      X  pathname                          |
  49  * X +22      2  file crc (CRC-16)                 |
  50  * X +24      Y  ext-header(old style)             v
  51  * -------------------------------------------------
  52  * X+Y+24        data                              ^
  53  *                 :                               | [*2] packed size
  54  *                 :                               v
  55  * -------------------------------------------------
  56  *
  57  * ext-header(old style)
  58  *     0      1  ext-type ('U')
  59  *     1      1  minor version
  60  *     2      4  UNIX time
  61  *     6      2  mode
  62  *     8      2  uid
  63  *    10      2  gid
  64  *
  65  * attribute (MS-DOS)
  66  *    bit1  read only
  67  *    bit2  hidden
  68  *    bit3  system
  69  *    bit4  volume label
  70  *    bit5  directory
  71  *    bit6  archive bit (need to backup)
  72  *
  73  */
  74
  75 /*
  76  * level 1 header
  77  *
  78  *
  79  * offset   size  field name
  80  * -----------------------------------
  81  *     0       1  header size   [*1]
  82  *     1       1  header sum
  83  *             -------------------------------------
  84  *     2       5  method ID                        ^
  85  *     7       4  skip size     [*2]               |
  86  *    11       4  original size                    |
  87  *    15       2  time                             |
  88  *    17       2  date                             |
  89  *    19       1  attribute (0x20 fixed)           | [*1] header size (X+Y+25)
  90  *    20       1  level (0x01 fixed)               |
  91  *    21       1  name length                      |
  92  *    22       X  filename                         |
  93  * X+ 22       2  file crc (CRC-16)                |
  94  * X+ 24       1  OS ID                            |
  95  * X +25       Y  ???                              |
  96  * X+Y+25      2  next-header size                 v
  97  * -------------------------------------------------
  98  * X+Y+27      Z  ext-header                       ^
  99  *                 :                               |
 100  * -----------------------------------             | [*2] skip size
 101  * X+Y+Z+27       data                             |
 102  *                 :                               v
 103  * -------------------------------------------------
 104  *
 105  */
 106
 107 /*
 108  * level 2 header
 109  *
 110  *
 111  * offset   size  field name
 112  * --------------------------------------------------
 113  *     0       2  total header size [*1]           ^
 114  *             -----------------------             |
 115  *     2       5  method ID                        |
 116  *     7       4  packed size       [*2]           |
 117  *    11       4  original size                    |
 118  *    15       4  time                             |
 119  *    19       1  RESERVED (0x20 fixed)            | [*1] total header size
 120  *    20       1  level (0x02 fixed)               |      (X+26+(1))
 121  *    21       2  file crc (CRC-16)                |
 122  *    23       1  OS ID                            |
 123  *    24       2  next-header size                 |
 124  * -----------------------------------             |
 125  *    26       X  ext-header                       |
 126  *                 :                               |
 127  * -----------------------------------             |
 128  * X +26      (1) padding                          v
 129  * -------------------------------------------------
 130  * X +26+(1)      data                             ^
 131  *                 :                               | [*2] packed size
 132  *                 :                               v
 133  * -------------------------------------------------
 134  *
 135  */
 136
 137 /*
 138  * level 3 header
 139  *
 140  *
 141  * offset   size  field name
 142  * --------------------------------------------------
 143  *     0       2  size field length (4 fixed)      ^
 144  *     2       5  method ID                        |
 145  *     7       4  packed size       [*2]           |
 146  *    11       4  original size                    |
 147  *    15       4  time                             |
 148  *    19       1  RESERVED (0x20 fixed)            | [*1] total header size
 149  *    20       1  level (0x03 fixed)               |      (X+32)
 150  *    21       2  file crc (CRC-16)                |
 151  *    23       1  OS ID                            |
 152  *    24       4  total header size [*1]           |
 153  *    28       4  next-header size                 |
 154  * -----------------------------------             |
 155  *    32       X  ext-header                       |
 156  *                 :                               v
 157  * -------------------------------------------------
 158  * X +32          data                             ^
 159  *                 :                               | [*2] packed size
 160  *                 :                               v
 161  * -------------------------------------------------
 162  *
 163  */