lib,rlc_am_nr: merge NACKs across SN overflows

lib/include/srsran/rlc/rlc_am_nr_packing.h

@@ -90,6 +90,8 @@ class rlc_am_nr_status_pdu_t
 private:
   /// Stored SN size required to compute the packed size
   rlc_am_nr_sn_size_t sn_size = rlc_am_nr_sn_size_t::nulltype;
+  /// Stored modulus to determine continuous sequences across SN overflows
+  uint32_t mod_nr = cardinality(rlc_am_nr_sn_size_t::nulltype);
   /// Internal NACK container; keep in sync with packed_size_
   std::vector<rlc_status_nack_t> nacks_ = {};
   /// Stores the current packed size; sync on each change of nacks_
@@ -109,8 +111,9 @@ public:
   const uint32_t& packed_size = packed_size_;
 
   rlc_am_nr_status_pdu_t(rlc_am_nr_sn_size_t sn_size);
-  void                                  reset();
-  void                                  push_nack(const rlc_status_nack_t& nack);
+  void reset();
+  bool is_continuous_sequence(const rlc_status_nack_t& left, const rlc_status_nack_t& right) const;
+  void push_nack(const rlc_status_nack_t& nack);
   const std::vector<rlc_status_nack_t>& get_nacks() const { return nacks_; }
   uint32_t                              get_packed_size() const { return packed_size; }
   bool                                  trim(uint32_t max_packed_size);

lib/src/rlc/rlc_am_nr_packing.cc

@@ -19,7 +19,8 @@ namespace srsran {
  * Container implementation for pack/unpack functions
  ***************************************************************************/
 
-rlc_am_nr_status_pdu_t::rlc_am_nr_status_pdu_t(rlc_am_nr_sn_size_t sn_size) : sn_size(sn_size)
+rlc_am_nr_status_pdu_t::rlc_am_nr_status_pdu_t(rlc_am_nr_sn_size_t sn_size) :
+  sn_size(sn_size), mod_nr(cardinality(sn_size))
 {
   nacks_.reserve(RLC_AM_NR_TYP_NACKS);
 }
@@ -32,10 +33,10 @@ void rlc_am_nr_status_pdu_t::reset()
   packed_size_ = rlc_am_nr_status_pdu_sizeof_header_ack_sn;
 }
 
-static bool is_continuous_sequence(const rlc_status_nack_t& left, const rlc_status_nack_t& right)
+bool rlc_am_nr_status_pdu_t::is_continuous_sequence(const rlc_status_nack_t& left, const rlc_status_nack_t& right) const
 {
   // SN must be continuous
-  if (right.nack_sn != left.has_nack_range ? left.nack_sn + left.nack_range : left.nack_sn + 1) {
+  if (right.nack_sn != ((left.has_nack_range ? left.nack_sn + left.nack_range : (left.nack_sn + 1)) % mod_nr)) {
     return false;
   }