libGDSII is a C++ library for working with GDSII binary data files,
intended primarily for use with the computational electromagnetism
codes scuff-em and meep but sufficiently general-purpose to allow
other uses as well.

The packages consists of

a C++ library (libGDSII) with API functions for reading, processing,
and exporting GDSII files

a command-line executable code (GDSIIConvert) for reporting statistics
on GDSII geometries and exporting them to other file formats, notably
including the GMSH geometry format.