Module codec 

The STEP codec: format detection, parse policy, and model I/O.

Two types rather than one configurable type. StepCodec is the strict reader and stays zero-sized, so it can be named as a value wherever a codec is needed. StepReader carries an explicit ParseOptions for consumers that opt into malformed-record recovery. Both implement Codec, so either can be stored in a Box<dyn Codec> alongside the other formats.

Lazy loading

A strict read validates every record and then decodes each entity on first access (see lazy.rs): opening a file costs a syntax pass instead of building every value, and memory holds the source plus what was touched. The model keeps its source, so Codec::read_bytes copies the input once; Codec::read_owned and Codec::read_path hand over or read a buffer without that copy. StepReader::eager restores decode-everything-now.

Structs

StepCodec

The STEP physical file codec.

StepReader

A STEP codec carrying an explicit parse policy.