Reader

Reader::open parses _HEADER.TXT, _extern.inf and _FUNCTNS.INF, and for every MS function its _FUNCnnn.IDX scan index and, when present, its _FUNCnnn.STS scan statistics. It does not read _CHROMS.INF or the _CHROnnn.DAT files. Spectrum data is read on demand from the corresponding _FUNCnnn.DAT files.

use openwraw::Reader;

let r = Reader::open("sample.raw")?;
println!("{} functions", r.functions.len());

Public types live under openwraw::raw:

Module	Purpose
`header`	`_HEADER.TXT` - metadata + calibration
`extern_inf`	`_extern.inf` - instrument geometry
`functions_inf`	`_FUNCTNS.INF` - function descriptors
`index`	`_FUNCnnn.IDX` - scan index (Variant A / B)
`data`	`_FUNCnnn.DAT` - spectrum decoders
`chroms`	`_CHROMS.INF` + `_CHROnnn.DAT`

Reader::ms_level(function) gives a function's MS level and Reader::precursor_mz(function, scan) a scan's precursor m/z (None for MS1 and MSe scans, and wherever the bundle stores none). The rules and their in-file evidence are in the format notes for _extern.inf and _FUNCnnn.STS.

The high-level Reader glues functions and their spectrum data together; chromatogram channels are a separate concern accessed directly through the chroms module (see Chromatograms). For byte-level access the parsers under openwraw::raw are also usable individually.

Note: the Python bindings expose this same reader as openwraw.RawReader (see Quickstart) - the "Raw" prefix is a Python-side naming choice, not the Rust type name.

Error handling

Public functions return openwraw::Result<T>. The error type (openwraw::Error) reports the failing file and the underlying cause. It is #[non_exhaustive], as are the public types under openwraw::raw; match them with a wildcard arm.

Reader::iter_spectra yields one Result per non-lock-mass scan. The openmassspec_core::SpectrumSource adapter, openwraw::mzml::WatersSource, does the same: a scan that cannot be decoded is an Err in its place, and so is a _CHROMS.INF or _CHROnnn.DAT that cannot be read. The mzML writers stop at the first such error. To write the readable records and count the rest:

use openmassspec_core::{write_mzml_with_options, RecordErrorPolicy, WriteOptions};
use openwraw::mzml::WatersSource;

let mut src = WatersSource::open("sample.raw")?;
let opts = WriteOptions::new().with_record_error_policy(RecordErrorPolicy::Skip);
let summary = write_mzml_with_options(&mut src, &mut out, &opts)?;
if summary.skipped() > 0 {
    eprintln!("{} records could not be decoded", summary.skipped());
}

In Python, RawReader.iter_records raises RuntimeError for a scan that cannot be decoded; calling next() again continues with the next scan.

Error handling​

Error handling