This is a small library that attempts to allow efficient reading of VCF and BCF files that are either compressed or uncompressed and indexed or not. rust_htslib is used for the parsing, this unifies handling above that.
Even when not indexed, it allows "skipping" via iterating until the requested region is reached. This is useful for bedder-rs but might also be useful elsewhere.
The skipping will be most efficient when the files are compressed and indexed.
This currently will may work as expected when there are multiple variants with the same position. That will depend on how it is called. This will be fixed in the future.
As implemented, only compressed, indexed VCF or BCF will have the absolute highest performance.
Others will require skipping via iterating over the file until the given region is reached.
This assumes that any indexed file will also support Seek.