WIB2Frame.hpp

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#ifndef FDDETDATAFORMATS_INCLUDE_FDDETDATAFORMATS_WIB2FRAME_HPP_
#define FDDETDATAFORMATS_INCLUDE_FDDETDATAFORMATS_WIB2FRAME_HPP_
 
#include <algorithm> // For std::min
#include <cassert>   // For assert()
#include <cstdint>   // For uint32_t etc
#include <cstdio>
#include <cstdlib>
#include <stdexcept> // For std::out_of_range
 
namespace dunedaq::fddetdataformats {

class WIB2Frame
{
public:
  // ===============================================================
  // Preliminaries
  // ===============================================================
 
  // The definition of the format is in terms of 32-bit words
  using word_t = uint32_t; // NOLINT
 
  static constexpr int s_bits_per_adc = 14;
  static constexpr int s_bits_per_word = 8 * sizeof(word_t);
  static constexpr int s_u_channels_per_femb = 40;
  static constexpr int s_v_channels_per_femb = 40;
  static constexpr int s_x_channels_per_femb = 48;
  static constexpr int s_channels_per_femb = s_u_channels_per_femb + s_v_channels_per_femb + s_x_channels_per_femb;
  static constexpr int s_fembs_per_frame = 2;
  static constexpr int s_num_channels = s_fembs_per_frame * s_channels_per_femb;
  static constexpr int s_num_adc_words = s_num_channels * s_bits_per_adc / s_bits_per_word;
  static constexpr int s_num_ch_per_frame = s_channels_per_femb * s_fembs_per_frame;
 
  struct Header
  {
    word_t version : 6, detector_id : 6, crate : 10, slot : 3, unused : 1, link : 6;
    word_t timestamp_1 : 32;
    word_t timestamp_2 : 32;
    word_t tbd_1 : 13, colddata_timestamp_id : 3, femb_valid : 2, link_mask : 8, lock_output_status : 1, tbd_2 : 5;
    word_t femb_pulser_frame_bits : 8, femb_sync_flags : 8, colddata_timestamp : 15, tbd_3 : 1;
  };
 
  struct Trailer
  {
    word_t flex_bits : 16, tbd_1 : 1, tbd_2 : 1, ws : 1, psr_cal : 4, ready : 1, context_code : 8;
  };
 
  // ===============================================================
  // Data members
  // ===============================================================
  Header header;
  word_t adc_words[s_num_adc_words]; // NOLINT
  Trailer trailer;
 
  // ===============================================================
  // Accessors
  // ===============================================================

  uint16_t get_adc(int i) const // NOLINT(build/unsigned)
  {
    if (i < 0 || i >= s_num_channels)
      throw std::out_of_range("ADC index out of range");
 
    // The index of the first (and sometimes only) word containing the required ADC value
    int word_index = s_bits_per_adc * i / s_bits_per_word;
    assert(word_index < s_num_adc_words);
    // Where in the word the lowest bit of our ADC value is located
    int first_bit_position = (s_bits_per_adc * i) % s_bits_per_word;
    // How many bits of our desired ADC are located in the `word_index`th word
    int bits_from_first_word = std::min(s_bits_per_adc, s_bits_per_word - first_bit_position);
    uint16_t adc = adc_words[word_index] >> first_bit_position; // NOLINT(build/unsigned)
    // If we didn't get the full 14 bits from this word, we need the rest from the next word
    if (bits_from_first_word < s_bits_per_adc) {
      assert(word_index + 1 < s_num_adc_words);
      adc |= adc_words[word_index + 1] << bits_from_first_word;
    }
    // Mask out all but the lowest 14 bits;
    return adc & 0x3FFFu;
  }

  void set_adc(int i, uint16_t val) // NOLINT(build/unsigned)
  {
    if (i < 0 || i >= s_num_channels)
      throw std::out_of_range("ADC index out of range");
    if (val >= (1 << s_bits_per_adc))
      throw std::out_of_range("ADC value out of range");
 
    // The index of the first (and sometimes only) word containing the required ADC value
    int word_index = s_bits_per_adc * i / s_bits_per_word;
    assert(word_index < s_num_adc_words);
    // Where in the word the lowest bit of our ADC value is located
    int first_bit_position = (s_bits_per_adc * i) % s_bits_per_word;
    // How many bits of our desired ADC are located in the `word_index`th word
    int bits_in_first_word = std::min(s_bits_per_adc, s_bits_per_word - first_bit_position);
    uint32_t mask = (1 << (first_bit_position)) - 1;
    adc_words[word_index] = ((val << first_bit_position) & ~mask) | (adc_words[word_index] & mask);
    // If we didn't put the full 14 bits in this word, we need to put the rest in the next word
    if (bits_in_first_word < s_bits_per_adc) {
      assert(word_index + 1 < s_num_adc_words);
      mask = (1 << (s_bits_per_adc - bits_in_first_word)) - 1;
      adc_words[word_index + 1] = ((val >> bits_in_first_word) & mask) | (adc_words[word_index + 1] & ~mask);
    }
  }

  uint64_t get_timestamp() const // NOLINT(build/unsigned)
  {
    return (uint64_t)header.timestamp_1 | ((uint64_t)header.timestamp_2 << 32); // NOLINT(build/unsigned)
  }

  void set_timestamp(const uint64_t new_timestamp) // NOLINT(build/unsigned)
  {
    header.timestamp_1 = new_timestamp;
    header.timestamp_2 = new_timestamp >> 32;
  }
};
 
} // namespace dunedaq::fddetdataformats
 
#endif // FDDETDATAFORMATS_INCLUDE_FDDETDATAFORMATS_WIB2FRAME_HPP_
 
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