Overall File Structure¶
All known files are little-endian. Seems to be what “Intel Format” at the top of the file is indicating.
The file is made up of a file header from bytes 0 through 4139, followed by 11 contiguous Data Blocks.
| File bytes | Numbers or ASCII | Description |
|---|---|---|
| 0-1 | Numbers | 0xAF, 0xAF (‘Magic Number’ 1sc file ID) |
| 2-31 | ASCII | Stable File Version 2.0\r\n<2 spaces>\r\n |
| 32-55 | ASCII | Intel Format<10 spaces>\r\n |
| 56-95 | ASCII | Bio-Rad Scan File - ID<space><17-digit number> |
| 96-135 | ASCII | <38 spaces>\r\n |
| 136-139 | Numbers | 0xC8, 0x00, 0x00, 0x00
(or uint32 0x000000C8 = 200)
|
| 140-143 | Numbers | 0x03, 0x00, 0x00, 0x00
(or uint32 0x00000003 = 3)
|
| 144-147 | Numbers | 0x00, 0x00, 0x00, 0x00
(or uint32 0x00000000 = 0)
|
| 148-151 | uint32 | Start of Data Block 0 (byte offset from start of file) |
| 152-155 | uint32 | <length of file after file header>
Number of bytes from start of Data
Block 0 to End Of File.
|
| 156-159 | Numbers | 0x00, 0x00, 0x01, 0x00 (or uint32 0x10000 = 4096) |
| 160-379 | Numbers | Data Fields describing Data Blocks
11x 20-byte Fields
|
| 380-4139 | Numbers | 3760 bytes of 0x00 |
| 4140- | Mixed | Start of Data Block 0 |
Within each Data Block are a series of Data Fields. (See Sections Field Structure and Field Types for descriptions)
Fields can contain references to other fields, by using a uint32 Data ID to refer to other fields. Each referenceable field has its own unique Data ID recorded in its Field Header.
The entire file can be parsed by reading a data format definition of a data Collection in each even-numbered Data Block, with the actual data in the following odd-numbered Data Block. The first Field in each odd-numbered Data Block is always (often?) the root Field of a hierarchical set of data based on references to other Data Fields inside the same Data Block.
Alternatively, after byte 4140, the entire file can be parsed as a series of contiguous Data Fields, with special parsing for Field Type 0 (End Of Data Block). If parsing the entire file at once, (and not each Data Block in isolation,) one can use the following method when encountering Field Type 0:
- Parse the End Of Data Block Field
- Field Type: 0
- Field Len: 8
- Field ID: 0
- Parse the Data Block Footer
- Keep reading groups of 7x uint16 values until the end of this Data Block, known from reading of the Data Block info fields in the File Header.
- Parse the next Data Block Header
- Read 2x uint32 values.