Function _reverse_file

libCacheSim/bin/traceUtils/traceConvLCS.cpp:330–419

* @brief read the reverse trace and write to the output file * * @param ofilepath * @param stat * @param output_txt * @param lcs_ver */

 * @param lcs_ver
 */
static void _reverse_file(std::string ofilepath, lcs_trace_stat_t stat, bool output_txt, int64_t lcs_ver) {
  size_t file_size;
  char *mapped_file = reinterpret_cast<char *>(utils::setup_mmap(ofilepath + ".reverse", &file_size));
  size_t pos = file_size;

  std::ofstream ofile(ofilepath, std::ios::out | std::ios::binary | std::ios::trunc);
  _write_lcs_header(ofile, stat, lcs_ver);

  INFO("start to reverse the trace...\n");
  std::ofstream ofile_txt;
  if (output_txt) ofile_txt.open(ofilepath + ".txt", std::ios::out | std::ios::trunc);

  lcs_req_full_t lcs_req_full;
  size_t lcs_full_req_entry_size = sizeof(lcs_req_full_t);

  // for lcs version 4-8, we need to read the features
  size_t n_features = 0;
  if (lcs_ver >= 4 && lcs_ver <= 8) {
    n_features = LCS_VER_TO_N_FEATURES[lcs_ver];
  }

  size_t entry_size = lcs_full_req_entry_size + n_features * sizeof(int32_t);

  while (pos >= entry_size) {
    pos -= entry_size;
    memcpy(&lcs_req_full, mapped_file + pos, lcs_full_req_entry_size);
    if (lcs_req_full.next_access_vtime != INT64_MAX) {
      /* req.next_access_vtime is the vtime start from the end */
      lcs_req_full.next_access_vtime = stat.n_req - lcs_req_full.next_access_vtime;
    }

    if (lcs_ver == 1) {
      lcs_req_v1_t lcs_req_v1;
      lcs_req_v1.clock_time = lcs_req_full.clock_time;
      lcs_req_v1.obj_id = lcs_req_full.obj_id;
      lcs_req_v1.obj_size = lcs_req_full.obj_size;
      lcs_req_v1.next_access_vtime = lcs_req_full.next_access_vtime;

      ofile.write(reinterpret_cast<char *>(&lcs_req_v1), sizeof(lcs_req_v1));
    } else if (lcs_ver == 2) {
      lcs_req_v2_t lcs_req_v2;
      lcs_req_v2.clock_time = lcs_req_full.clock_time;
      lcs_req_v2.obj_id = lcs_req_full.obj_id;
      lcs_req_v2.obj_size = lcs_req_full.obj_size;
      lcs_req_v2.op = lcs_req_full.op;
      lcs_req_v2.tenant = lcs_req_full.tenant;
      lcs_req_v2.next_access_vtime = lcs_req_full.next_access_vtime;

      ofile.write(reinterpret_cast<char *>(&lcs_req_v2), sizeof(lcs_req_v2));
    } else if (lcs_ver == 3) {
      lcs_req_v3_t lcs_req_v3;
      lcs_req_v3.clock_time = lcs_req_full.clock_time;
      lcs_req_v3.obj_id = lcs_req_full.obj_id;
      lcs_req_v3.ttl = lcs_req_full.ttl;
      lcs_req_v3.obj_size = lcs_req_full.obj_size;
      lcs_req_v3.op = lcs_req_full.op;
      lcs_req_v3.tenant = lcs_req_full.tenant;
      lcs_req_v3.next_access_vtime = lcs_req_full.next_access_vtime;