leonarski_fandClaude Opus 5.5
ae4786d14f
Not yet compiled or tested: work stopped after the feasibility study. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
51 lines
2.5 KiB
C++
51 lines
2.5 KiB
C++
// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
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// SPDX-License-Identifier: GPL-3.0-only
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#pragma once
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#include <cstdint>
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#include <string>
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#include <vector>
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// The LCLS-I XTC container, as far as reading camera frames out of it needs: what the LCLS data
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// system (pdsdata) wrote at LCLS until 2023, and what serial-crystallography depositions from that
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// era (Rayonix at MFX and XPP) are archived as.
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//
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// A file is a sequence of datagrams. Each is a 40-byte header - the event's clock time and timestamp
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// (16 bytes, whose top bits name the transition: Configure, BeginRun, ..., L1Accept for an event),
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// an environment word, and the outermost Xtc header - followed by the Xtc's payload. An Xtc header is
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// five 32-bit words: damage, the source (two words), the type and version, and the extent, which
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// counts the header itself. A container (type Id_Xtc) holds further Xtcs one after another; anything
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// else is a leaf holding one data object. A camera image is a leaf of type Id_Frame (Camera::FrameV1):
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// width, height, bit depth and offset, 32 bits each, then the pixels row by row. Everything is
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// little-endian and uncompressed.
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//
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// A run is written as several streams (-s00, -s01, ...) by different recorders, each holding a
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// share of the events. Their order across streams is the event time, which this reader does not
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// reconstruct: stills are independent, so the streams are read one after another.
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namespace xtc {
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// One camera image: where its pixels start in which file.
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struct Frame {
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std::string file;
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uint64_t offset = 0; // of the first pixel
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uint32_t width = 0;
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uint32_t height = 0;
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};
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// True if the path is an XTC file (or a directory holding one) - by its first datagram, not its name.
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bool CanRead(const std::string &path);
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// The event streams of the path: the file itself, or every XTC file in a directory, by name. The
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// "smalldata" copies (.smd.xtc) carry the events without their images and are left out.
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std::vector<std::string> CollectStreams(const std::string &path);
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// Every L1Accept of the file that holds a 16-bit camera image, in file order. Where an event holds
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// images from more than one camera, the largest is taken - the diffraction detector.
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std::vector<Frame> IndexFrames(const std::string &file);
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// Reads one image as 32-bit pixels into out (width*height values), through scratch.
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void ReadFrame(const Frame &frame, int32_t *out, std::vector<uint8_t> &scratch);
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} // namespace xtc
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