Fragment.h

// Fragment.h
#ifndef EVENTBUILDER_FRAGMENT_H
#define EVENTBUILDER_FRAGMENT_H
 
#include <vector>
#include <cstdint>
 
namespace eventbuilder {
 
// Define a simple CRC32 implementation for checksum
inline uint32_t crc32(const std::vector<uint8_t>& data) {
    uint32_t crc = 0xFFFFFFFF;
    for (uint8_t c : data) {
        crc ^= static_cast<uint8_t>(c);
        for (int i = 0; i < 8; ++i) {
            if (crc & 1) {
                crc = (crc >> 1) ^ 0xEDB88320;
            } else {
                crc >>= 1;
            }
        }
    }
    return ~crc;
}
 
enum class ContributorId {
    Channel,
    Module
};
 
struct FragmentTrailer {
    uint32_t checksum; // For error detection
};
 
struct FragmentHeader {
    // Header Word 0
    uint64_t magic_number : 8;      // 0xA5
    uint64_t contributor_id : 8;
    uint64_t subsystem_id : 8;
    uint64_t version : 8;
    uint64_t padding : 32;          // Unused bits
 
    // Header Word 1
    uint64_t timestamp;
};
 
// Represents a single data fragment
struct DataFragment {
    FragmentHeader header;
    std::vector<uint8_t> payload; // Raw byte data from the readout
    FragmentTrailer trailer;
};
 
} // namespace eventbuilder
 
#endif