Module header 

VCF/BCF header representation and manipulation.

This module provides the Header struct, which wraps an htslib bcf_hdr_t pointer and provides safe access to header metadata including sample names, INFO/FORMAT field definitions, and header modification.

Ownership

Header owns its underlying bcf_hdr_t* via duplication. This ensures correct lifetime management and thread safety - the header can outlive the reader it was created from.

Caching

Sample names and tag ID-to-name mappings are cached at construction time for O(1) lookups during variant processing.

Example

use htsvcf_core::header::Header;
use rust_htslib::bcf::{self, Read};

let reader = bcf::Reader::from_path("input.vcf.gz").unwrap();
let header = unsafe { Header::new(reader.header().inner) };

// Access sample information
println!("Samples: {:?}", header.sample_names());

// Look up INFO field type
if let Some((ty, len)) = header.info_type(b"DP") {
    println!("DP is {:?} with length {:?}", ty, len);
}

Structs

Header

A VCF/BCF header with metadata and sample information.

HeaderField

Represents a field definition from the VCF header (INFO, FORMAT, or FILTER).