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Jungfraujoch/reader/JFJochCBFReader.h
T
leonarski_fandClaude Opus 5 dc16a00271 reader: read a PILATUS miniCBF sweep natively, without libcbf
Most facilities still archive rotation data as a directory of miniCBF frames, which until now had
to be converted to HDF5 before rugnux could see it. Nothing in that format needs a CIF parser or a
library: it is an ASCII header, four separator bytes, then one byte-offset compressed image, and
every value the reader wants sits on a "# " comment line or a MIME line.

MiniCBF holds the format itself - header parse and the byte-offset decoder, which is a running
value with deltas stored smallest-container-first. Verified byte-exact against dxtbx on PILATUS 6M,
6M-F, 300K, silicon and CdTe sensors, and three sensor thicknesses.

JFJochCBFReader is a sibling of JFJochHDF5Reader under the JFJochReader base. NAMING ANY FRAME
READS ITS WHOLE SWEEP: the sweep is identified by the template (prefix + digit count) the named
frame belongs to, not by "every .cbf in the directory", so a directory holding two sweeps does not
splice two crystals together. Naming a directory takes the sweep with the most frames in it.

Images decode on demand, one per call, so any number of workers can read at once - there is no
global lock as there is on the HDF5 path, HDF5 not being thread-safe. A raw CBF carries no analysis
results, so the dataset it builds is the geometry, the mask and nothing else, exactly as a plain
DECTRIS file with no /entry/MX gives.

Two header quirks are handled because real files have them: the sensor material is written
"Silicon" where the rest of the code compares against "CdTe", and the thickness unit is sometimes
omitted. Headers are not a fixed size either - one set carries 6335 bytes - so the parse runs to
the binary separator rather than over a fixed prefix.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-28 20:12:36 +02:00

55 lines
2.3 KiB
C++

// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only
#pragma once
#include <string>
#include <vector>
#include "JFJochReader.h"
#include "MiniCBF.h"
// Reads a rotation sweep straight from a directory of PILATUS miniCBF files - the form most
// facilities still archive - with no conversion step and no libcbf.
//
// The sweep's geometry comes from the first file's header; the rotation angle of each image comes
// from its own header, which costs only the bytes up to the binary separator. Images are decoded on
// demand, one per call, so any number of workers can read at once - there is no global lock as there
// is on the HDF5 path, HDF5 not being thread-safe.
//
// A raw CBF carries no analysis results, so this reader has no spots, no reflections and no snapshots;
// the dataset it builds is the geometry, the mask and nothing else, exactly as a plain DECTRIS file
// with no /entry/MX would give.
class JFJochCBFReader : public JFJochReader {
std::vector<std::string> files_;
std::shared_ptr<JFJochReaderDataset> dataset_;
minicbf::Header header0_;
bool LoadImage_i(std::shared_ptr<JFJochReaderDataset> &dataset,
DataMessage &message,
std::vector<uint8_t> &buffer,
int64_t image_number,
bool update_dataset) override;
// Decodes one image into the caller's byte buffer (RawByteBuffer or std::vector<uint8_t>) and
// returns the image that points at it.
template <class Buffer>
CompressedImage DecodeInto(int64_t image_number, Buffer &buffer) const;
public:
~JFJochCBFReader() override = default;
// True if the path names something this reader can open: a miniCBF file, or a directory holding
// at least one. Cheap - it reads a few kB at most.
static bool CanRead(const std::string &path);
// path is a directory of *.cbf, or one *.cbf inside the sweep to take the whole directory from.
void ReadFiles(const std::string &path);
[[nodiscard]] uint64_t GetNumberOfImages() const override;
void Close() override;
std::shared_ptr<JFJochReaderRawImage> GetRawImage(int64_t image_number) override;
[[nodiscard]] std::vector<SpotToSave> ReadSpots(int64_t image) const override;
};