Header Section
Header Section
10 bytes header data. This section is guaranteed to be found at the very start of the file. It is the only section that starts at an unchanging offset.
The first long determines the layout of this section. The following values are found:
Value ID 1 Description
37 00 00 10 ID 10000037 File, with a Section Table Section
41 00 00 10 Clip Art File
50 00 00 10 ID 10000050 File, structured as a list of sections.
Files starting with ID 37 00 00 10 have a Section Table Offset Section with the offset of the Section Table Section directly after the Header Section. This is better described in the File Structure chapter.
Offset Data Description
0000 ID UID1: 37 00 00 10: Header Section layout
0004 ID UID2: File kind
0008 ID UID3: Application ID
000C L UID4: Checksum of UID1, UID2 and UID3
0010
UID2 tells what kind of file is found. The values below are known:
UID2 UID1 Desciption
6D 00 00 10 37 00 00 10 Data file
UID3 is the Application ID. It is the same as used in the Application ID Section.
UID4 is a checksum of UID1 to UID3. It is computed by taking the exclusive-or (xor) of the values found it the tables below. Each value is only used when the corresponding bit is set to one.
UID4 can also be computed by using OPL function CheckUID$.
UID1 bit Value
bit 0 0x000045A0
bit 1 0x00008B40
bit 2 0x000006A1
bit 3 0x00000D42
bit 4 0x00001A84
bit 5 0x00003508
bit 6 0x00006A10
bit 7 0x0000D420
bit 8 0x45A00000
bit 9 0x8B400000
bit 10 0x06A10000
bit 11 0x0D420000
bit 12 0x1A840000
bit 13 0x35080000
bit 14 0x6A100000
bit 15 0xD4200000
bit 16 0x0000AA51
bit 17 0x00004483
bit 18 0x00008906
bit 19 0x0000022D
bit 20 0x0000045A
bit 21 0x000008B4
bit 22 0x00001168
bit 23 0x000022D0
bit 24 0xAA510000
bit 25 0x44830000
bit 26 0x89060000
bit 27 0x022D0000
bit 28 0x045A0000
bit 29 0x08B40000
bit 30 0x11680000
bit 31 0x22D00000
UID2 bit Value
bit 0 0x000076B4
bit 1 0x0000ED68
bit 2 0x0000CAF1
bit 3 0x000085C3
bit 4 0x00001BA7
bit 5 0x0000374E
bit 6 0x00006E9C
bit 7 0x0000DD38
bit 8 0x76B40000
bit 9 0xED680000
bit 10 0xCAF10000
bit 11 0x85C30000
bit 12 0x1BA70000
bit 13 0x374E0000
bit 14 0x6E9C0000
bit 15 0xDD380000
bit 16 0x00003730
bit 17 0x00006E60
bit 18 0x0000DCC0
bit 19 0x0000A9A1
bit 20 0x00004363
bit 21 0x000086C6
bit 22 0x00001DAD
bit 23 0x00003B5A
bit 24 0x37300000
bit 25 0x6E600000
bit 26 0xDCC00000
bit 27 0xA9A10000
bit 28 0x43630000
bit 29 0x86C60000
bit 30 0x1DAD0000
bit 31 0x3B5A0000
UID3 bit Value
bit 0 0x00003331
bit 1 0x00006662
bit 2 0x0000CCC4
bit 3 0x000089A9
bit 4 0x00000373
bit 5 0x000006E6
bit 6 0x00000DCC
bit 7 0x00001B98
bit 8 0x33310000
bit 9 0x66620000
bit 10 0xCCC40000
bit 11 0x89A90000
bit 12 0x03730000
bit 13 0x06E60000
bit 14 0x0DCC0000
bit 15 0x1B980000
bit 16 0x00001021
bit 17 0x00002042
bit 18 0x00004084
bit 19 0x00008108
bit 20 0x00001231
bit 21 0x00002462
bit 22 0x000048C4
bit 23 0x00009188
bit 24 0x10210000
bit 25 0x20420000
bit 26 0x40840000
bit 27 0x81080000
bit 28 0x12310000
bit 29 0x24620000
bit 30 0x48C40000
bit 31 0x91880000
