Setting a byte offset in a flat structure

Use a SetElementProperty and a GetElementProperty function to edit a byte offset in an element.

About this task

In this example, you have a flat file with a root element and three child elements named a, b and c, with the following sample data:

A1111B2222C00003333

Each child element has an initiator, A, B and C respectively. The goal is to configure the c element to ignore the 0000 part of the value.

1. Open the Util tab for the c element.
2. Drag and drop a SetElementProperty function in the Util tab.
3. Drag and drop an Add function on the Value argument.
4. Drag and drop a GetElementProperty function on the First Value argument.
5. Double-click the GetElementProperty function and select Byte offset in the Property drop-down list, then click OK.
6. Drag and drop the c element on the Element argument of the GetElementProperty function.
7. Drag and drop a Constant function on the Second Value argument.
8. Double-click the Constant function and enter 4 in the Value field, then click OK.

Results

The expression created indicates that the byte offset for the c elements should be calculated by adding the four bytes to ignore to the current offset of the c element, which is called by the GetElementProperty element.

If you want to check that the new offset is correct, you can create a map with this structure as both input and output.

When using the Test Run feature, you should get the following result:

A1111B2222C3333