DXF processing: calculating absolute coordinates of LINEs inside blocks

I have a software that needs to process dxf files and I am having a
nightmare trying to find the absolute corrdinates of LINEs inside
blocks.

This is what I know about BLOCKS:

Each BLOCK (in the BLOCKS section) has a block name that is related to
an INSERT entity (In the ENTITIES section).
The INSERT entity defines the transformation parameters such as origin,
scale and rotation, to transform the BLOCK coordinates from relative to
absolute coordinates.
All coordinates in the BLOCK may be transformed using the parameters
defined in INSERT.
Each BLOCK ends with ENDBLK.

This is what I need to do:

I need to transform the relative coordinates of LINEs inside blocks (in
the BLOCKS section) to absolute coordinates.
What I do is search (using the block name) the corresponding INSERT
entity (in the ENTITIES section) which gives me the coordinates of the
block, so by adding the relative + block corrdinates I can obtain the
absolute coordinates for LINEs.

SO FAR THE EXPLANATION, NOW THE PROBLEM TO SOLVE:

What can I do if I find more than one INSERT entity with the same block
name ?
How do I know which one applies to each LINE, since for a given block
name there is only one BLOCK structure in the blocks SECTION but in
some cases there is more than one INSERT entity in the ENTITIES
section.

Thanks for your help
Jose Maria

 

Autodesk publishes a DXF reference. The 2002 version is available at

http://www.autodesk.com/techpubs/autocad/dxf/dxf2002.pdf

Henrik Vallgren
www.streamspace.com