C++ c4_Column::InsertData方法代码示例

//.........这里部分代码省略.........
        mc->SetLocation(posVec.GetInt(r), sz);
      }
    }
  } else {
    pers_.FetchOldLocation(_data);

    if (type_ == 'B') {
      pers_.FetchOldLocation(sizes);

#if !q4_OLD_IS_ALWAYS_V2

      // WARNING - HUGE HACK AHEAD - THIS IS NOT 100% FULLPROOF!
      //
      // The above is correct for MK versions 2.0 and up, but *NOT*
      // for MK 1.8.6 datafiles, which store sizes first (OUCH!!!).
      // This means that there is not a 100% safe way to auto-convert
      // both 1.8.6 and 2.0 files - since there is no way to detect
      // unambiguously which version a datafile is.  All we can do,
      // is to carefully check both vectors, and *hope* that only one
      // of them is valid as sizes vector.  This problem applies to
      // the 'B' (bytes) property type only, and only pre 2.0 files.
      //
      // To build a version which *always* converts assuming 1.8.6,
      // add flag "-Dq4_OLD_IS_PRE_V2" to the compiler command line.
      // Conversely, "-Dq4_OLD_IS_ALWAYS_V2" forces 2.0 conversion.

      if (rows > 0) {
        t4_i32 s1 = sizes.ColSize();
        t4_i32 s2 = _data.ColSize();

#if !q4_OLD_IS_PRE_V2
        // if the size vector is clearly impossible, swap vectors
        bool fix = c4_ColOfInts::CalcAccessWidth(rows, s1) < 0;

        // if the other vector might be valid as well, check further
        if (!fix && c4_ColOfInts::CalcAccessWidth(rows, s2) >= 0) {
          sizes.SetRowCount(rows);
          t4_i32 total = 0;
          for (int i = 0; i < rows; ++i) {
            t4_i32 w = sizes.GetInt(i);
            if (w < 0 || total > s2) {
              total =  - 1;
              break;
            }
            total += w;
          }

          // if the sizes don't add up, swap vectors
          fix = total != s2;
        }

        if (fix)
#endif 
         {
          t4_i32 p1 = sizes.Position();
          t4_i32 p2 = _data.Position();
          _data.SetLocation(p1, s1);
          sizes.SetLocation(p2, s2);
        }
      }
#endif 
      InitOffsets(sizes);
    } else {
      d4_assert(type_ == 'S');

      sizes.SetRowCount(rows);

      t4_i32 pos = 0;
      t4_i32 lastEnd = 0;
      int k = 0;

      c4_ColIter iter(_data, 0, _data.ColSize());
      while (iter.Next()) {
        const t4_byte *p = iter.BufLoad();
        for (int j = 0; j < iter.BufLen(); ++j)
        if (!p[j]) {
          sizes.SetInt(k++, pos + j + 1-lastEnd);
          lastEnd = pos + j + 1;
        }

        pos += iter.BufLen();
      }

      d4_assert(pos == _data.ColSize());

      if (lastEnd < pos) {
        // last entry had no zero byte
        _data.InsertData(pos++, 1, true);
        sizes.SetInt(k, pos - lastEnd);
      }

      InitOffsets(sizes);

      // get rid of entries with just a null byte
      for (int r = 0; r < rows; ++r)
        if (c4_FormatB::ItemSize(r) == 1)
          SetOne(r, c4_Bytes());
    }
  }
}