void c4_FormatB::InitOffsets(c4_ColOfInts& sizes_)
{
  int rows = Owner().NumRows();

  if (sizes_.RowCount() != rows) {
    sizes_.SetRowCount(rows);
  }

  _memos.SetSize(rows);
  _offsets.SetSize(rows + 1);

  if (_data.ColSize() > 0) {
    t4_i32 total = 0;

    for (int r = 0; r < rows; ++r) {
      int n = sizes_.GetInt(r);
      d4_assert(n >= 0);
      total += n;
      _offsets.SetAt(r + 1, total);
    }

    d4_assert(total == _data.ColSize());
  }
  
}

void c4_FormatX::Define(int rows_, const t4_byte** ptr_)
{
  if (ptr_ != 0)
    _data.PullLocation(*ptr_);
    
  _data.SetRowCount(rows_);
}

void c4_FormatB::Define(int, const t4_byte **ptr_) {
  d4_assert(_memos.GetSize() == 0);

  if (ptr_ != 0) {
    _data.PullLocation(*ptr_);
    if (_data.ColSize() > 0)
      _sizeCol.PullLocation(*ptr_);
    _memoCol.PullLocation(*ptr_);
  }

  // everything below this point could be delayed until use
  // in that case, watch out that column space use is properly tracked

  InitOffsets(_sizeCol);

  if (_memoCol.ColSize() > 0) {
    c4_Bytes walk;
    _memoCol.FetchBytes(0, _memoCol.ColSize(), walk, true);

    const t4_byte *p = walk.Contents();

    for (int row = 0; p < walk.Contents() + walk.Size(); ++row) {
      row += c4_Column::PullValue(p);
      d4_assert(row < _memos.GetSize());

      c4_Column *mc = d4_new c4_Column(_data.Persist());
      d4_assert(mc != 0);
      _memos.SetAt(row, mc);

      mc->PullLocation(p);
    }

    d4_assert(p == walk.Contents() + walk.Size());
  }
}

void c4_FormatB::Unmapped() {
  _data.ReleaseAllSegments();
  _sizeCol.ReleaseAllSegments();
  _memoCol.ReleaseAllSegments();

  for (int i = 0; i < _memos.GetSize(); ++i) {
    c4_Column *cp = (c4_Column*)_memos.GetAt(i);
    if (cp != 0)
      cp->ReleaseAllSegments();
  }
}

void c4_FormatB::Commit(c4_SaveContext &ar_) {
  int rows = _memos.GetSize();
  d4_assert(rows > 0);

  bool full = _recalc || ar_.Serializing();

  if (!full)
  for (int i = 0; i < rows; ++i) {
    c4_Column *col = (c4_Column*)_memos.GetAt(i);
    if (col != 0) {
      full = true;
      break;
    }
  }
  d4_assert(_recalc || _sizeCol.RowCount() == rows);

  if (full) {
    _memoCol.SetBuffer(0);
    _sizeCol.SetBuffer(0);
    _sizeCol.SetAccessWidth(0);
    _sizeCol.SetRowCount(rows);

    int skip = 0;

    c4_Column *saved = ar_.SetWalkBuffer(&_memoCol);

    for (int r = 0; r < rows; ++r) {
      ++skip;

      t4_i32 start;
      c4_Column *col;
      int len = ItemLenOffCol(r, start, col);

      bool oldMemo = col !=  &_data;
      bool newMemo = ShouldBeMemo(len);

      if (!oldMemo && newMemo) {
        col = GetNthMemoCol(r, true);
        d4_assert(col !=  &_data);
        //? start = 0;
      }

      c4_Bytes temp;

      if (newMemo) {
        // it now is a memo, inlined data will be empty
        ar_.StoreValue(skip - 1);
        skip = 0;
        ar_.CommitColumn(*col);
      } else if (!oldMemo) {
        // it was no memo, done if it hasn't become one
        _sizeCol.SetInt(r, len);
        continue;
      } else {
        // it was a memo, but it no longer is
        d4_assert(start == 0);
        if (len > 0) {
          _sizeCol.SetInt(r, len);
          col->FetchBytes(start, len, temp, true);
          delete (c4_Column*)_memos.GetAt(r); // 28-11-2001: fix mem leak
          _memos.SetAt(r, 0); // 02-11-2001: fix for use after commit
        }
      }

      SetOne(r, temp, true); // bypass current memo pointer
    }

    ar_.SetWalkBuffer(saved);
  }

  ar_.CommitColumn(_data);

  if (_data.ColSize() > 0) {
    _sizeCol.FixSize(true);
    ar_.CommitColumn(_sizeCol);
    //_sizeCol.FixSize(false);
  }

  ar_.CommitColumn(_memoCol);

  // need a way to find out when the data has been committed (on 2nd pass)
  // both _sizeCol and _memoCol will be clean again when it has
  // but be careful because dirty flag is only useful if size is nonzero
  if (_recalc && !ar_.Serializing())
    _recalc = _sizeCol.ColSize() > 0 && _sizeCol.IsDirty() || _memoCol.ColSize()
      > 0 && _memoCol.IsDirty();
}