Description:
Moves the pointer to a given offset from the end of the layer, where the size of the offset is provided in another field. The first parameter is the field which contains the value of the offset and the second is the unit (see the Fixed Size Method). Thus (FromEndSizeFromField size_of_crc Bytes) would get the value stored in the field size_ of_crc and move the pointer that many bytes prior to the end of the layer. The second parameter is optional and, if omitted, will default to Bytes.
Parameters:
|
[Required] |
Filed |
"Field that contains offset" |
|
|
[Optional] |
List |
"Units" |
(Default value: Bytes) |
|
List values: |
Bit |
||
|
Bits |
|||
|
Times |
|||
|
Nibble |
|||
|
Nibbles |
|||
|
Byte |
|||
|
Bytes |
|||
|
Octet |
|||
|
Octets |
|||
|
Word |
|||
|
Words |
|||
|
Dword |
|||
|
Dwords |
|||
|
Qword |
|||
|
Qwords |
Example:
FIELD crc_value START_BIT (FromEndSizeFromField size_of_crc Bytes) (FromField Bytes size_of_ crc) "CRC"